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SEVENTH FRAMEWORK PROGRAMME Capacities Specific Programme
Research Infrastructures
Project No.: 227887
SERIES SEISMIC ENGINEERING RESEARCH INFRASTRUCTURES FOR
EUROPEAN SYNERGIES
Workpackage [WP10/TA6 – IFSTTAR Centrifuge]
DRESBUS II Investigation of the Seismic Behaviour of Shallow Rectangular
Underground Structures in Soft Soils Using Centrifuge Experiments
User Group Leader: Dr. E. Rovithis Revision: Final
May, 2013
SERIES 227887 TA Project: DRESBUS II
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ABSTRACT
This report contains centrifuge recordings and data interpretation as the outcome of the
Transnational Access project DRESBUS II “Investigation of the seismic behavior of shallow
rectangular underground structures in soft soils using centrifuge experiments” that was
performed under SERIES Research Program. DRESBUS II was designed, compiled and
completed on December 2012, as a collaborative project between the Institut Français des
Sciences et Technologie des Transports, de l'Amménagement et des Réseaux, France (IFSTTAR)
(acting as the Access Provider), the Earthquake Planning and Protection Organization, Greece
(EPPO-ITSAK) and the Laboratory of Soil Mechanics, Foundations and Geotechnical
Earthquake Engineering of Aristotle University of Thessaloniki, Greece (AUTH), both of them
acting as the main Transnational Access Users.
Seven centrifuge test sequences were carried out in total referring to flexible or rigid tunnel
sections, smooth or rough soil-tunnel interface (smoothed aluminium surface and grooved
aluminium with depth equivalent to sand D50) and dry or saturated Fontainebleau sand N34 with
ID = 70%. Novel techniques for the sand pluvation, models saturation and waterproofing of the
tunnel sections were used during centrifuge tests set-up. Each soil-tunnel system was excited by
the same input sequence: a real recording from Northridge earthquake scaled to three levels of
peak acceleration (0.1g, 0.2g and 0.3g) followed by a sine wave at 0.3g. A dense monitoring
scheme was employed to record soil-tunnel response comprising of miniature piezoelectric
accelerometers within the soil or attached to the tunnel section and the ESB container,
displacement sensors to record the surface ground settlement and pore pressure sensors to
measure pore pressure dissipation, for the saturated cases. Furthermore, specially designed
extensometers were used to record the racking deformations of the tunnel section and diagonal
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“blade” extensometers were installed along the longitudinal axis of the tunnel to verify the
homogeneity of deformation and control out of plane response of the structure.
Experimental recordings obtained from each test are reported herein in detail followed by a
preliminary interpretation of the experimental data. Seismic response of the tunnel sections is
commented as affected by the model parameters under investigation. In this regard, the acquired
datasets offer valuable experimental evidence on fundamental aspects of seismic behaviour of
soil-tunnel systems, providing a well-documented basis for validating numerical models and
design methods that are commonly employed in practice.
Keywords: Dynamic centrifuge tests, Rectangular tunnels, Racking deformations
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ACKNOWLEDGMENTS
The research leading to these results has received funding from the European Community’s
Seventh Framework Programme [FP7/2007-2013] under grant agreement n° 227887.
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REPORT CONTRIBUTORS
AUTH (Greece) Grigorios Tsinidis
EPPO (Greece) Emmanouil Rovithis
AUTH (Greece) Kyriazis Pitilakis
IFSTTAR (France) Jean-Luis Chazelas
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CONTENTS
List of Figures ............................................................................................................................... viii
List of Tables .................................................................................................................................. xv
1 Introduction .............................................................................................................................1
2 DRESBUS II experimental program..........................................................................................3
2.1 IFSTTAR Centrifuge facility ...........................................................................................3
2.2 Centrifuge Scaling laws..................................................................................................4
2.3 Fontainebleau sand properties ......................................................................................4
2.4 Tunnel models ................................................................................................................5
2.4.1 Models dimensions ............................................................................................5
2.4.2 Soil‐tunnel interface rugosity............................................................................6
2.4.3 Aluminium mechanical properties ....................................................................7
2.4.4 Flexibility ratios..................................................................................................8
2.5 Models preparation ........................................................................................................9
2.5.1 Sand pouring......................................................................................................9
2.5.2 Saturation procedure.......................................................................................10
2.5.3 Treatment of model tunnels boundaries ........................................................12
2.6 Model layout ‐ Instrumentation scheme .....................................................................14
2.6.1 Miniature accelerometers ...............................................................................15
2.6.2 Displacement sensors......................................................................................16
2.6.3 Pore pressure cells ...........................................................................................17
2.6.4 Walls deformations extensometers ................................................................17
2.6.5 Diagonal extensometers .................................................................................20
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2.7 Testing program...........................................................................................................22
2.8 Experimental procedure ..............................................................................................22
2.9 Input motion characteristics ........................................................................................24
3 Data processing .....................................................................................................................25
3.1 Accelerations ................................................................................................................25
3.2 Effect of filtering technique on tunnel distortion recordings .....................................27
3.3 Water Pore pressures ...................................................................................................27
4 Experimental data..................................................................................................................28
4.1 Test DRESBUS_2_1_1 ..................................................................................................28
4.2 Test DRESBUS_2_2_1..................................................................................................50
4.3 Test DRESBUS_2_3_1 ..................................................................................................65
4.4 Test DRESBUS_2_4_1..................................................................................................80
4.5 Test DRESBUS_2_4_2 .................................................................................................81
4.6 Test DRESBUS_2_5_1 ..................................................................................................99
4.7 Test DRESBUS_2_6_1................................................................................................113
4.8 Test DRESBUS_2_7_1 ................................................................................................129
5 Interpretation of experimental data.....................................................................................145
5.1 CPT data during test sequence ..................................................................................145
5.2 Recorded soil amplification .......................................................................................145
5.3 Tunnels racking deformations ...................................................................................147
5.3.1 Input motion amplitude effect ......................................................................147
5.3.2 Tunnel stiffness effect ...................................................................................151
5.3.3 Soil‐tunnel interface effect............................................................................151
5.3.4 Soil saturation effect .....................................................................................154
6 Conclusions ..........................................................................................................................155
References ....................................................................................................................................156
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List of Figures
Fig. 1.1 Daikai Station. (a) Settlements of the overlaying roadway caused by the subway collapse, (b) Collapse of the central columns of the station (Special Issue of Soil and Foundations, 1996) ......................................................................................................................... 2 Fig.2.1 (a) Geotechnical Centrifuge at IFSTTAR, (b) Earthquake Actidyn QS 80 actuator, (c) ESB container ................................................................................................................................. 3 Fig. 2.2 Tunnels sections ................................................................................................................ 5 Fig. 2.3 Definition of roughness ..................................................................................................... 6 Fig. 2.4 Relation between the sand grain size and the grooves dimensions ................................... 6 Fig. 2.5 Device for the deformation tests of the tunnel specimens................................................. 7 Fig. 2.6 Small strain shear wave velocity profiles according to Hardin and Drenvich model ....... 8 Fig. 2.7 Model preparation.............................................................................................................. 9 Fig. 2.8 Installation of the waterproof rubber membrane on the ESB container .......................... 11 Fig. 2.9 Schematic representation of the saturation system setup ................................................ 12 Fig. 2.10 Saturation system setup ................................................................................................. 12 Fig. 2.11 Typical connection of the tunnel with the ESB box for the dry sand tests.................... 13 Fig. 2.12 Details of the tunnels – ESB box connections (a) Dry sand tests, (b) Saturated sand tests; first solution, (c) Saturated sand tests; final solution........................................................... 13 Fig. 2.13 Typical model layout for a dry test................................................................................ 15 Fig. 2.14 Typical model layout for a saturated test....................................................................... 16 Fig. 2.15 “Fork” system extensometer.......................................................................................... 18 Fig. 2.16 Design sheet of the fork extensometers......................................................................... 19 Fig. 2.17 Calibration device for the fork extensometers - Representative calibration curves of a fork system.................................................................................................................................... 20 Fig. 2.18 Diagonal extensometers................................................................................................. 20 Fig. 2.19 Design sheet for the diagonal extensometers ................................................................ 21 Fig. 2.20 Calibration device for the diagonal extensometers........................................................ 21 Fig. 2.21 Shaking table base configuration................................................................................... 23 Fig. 2.22 Relative position of the CPT with respect to the tunnel (top view) .............................. 23 Fig. 2.23 Nominal input motions .................................................................................................. 24 Fig. 4.1 Test DRESBUS_2_1_1 model set up and instrumentation scheme ................................ 28 Fig. 4.2 Accelerometers vertical arrays ........................................................................................ 30 Fig. 4.3 Processed acceleration time histories – EQ1................................................................... 33 Fig. 4.4 Processed acceleration time histories – EQ2................................................................... 34 Fig. 4.5 Processed acceleration time histories – EQ3................................................................... 35 Fig. 4.6 Processed acceleration time histories – EQ4................................................................... 36
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Fig. 4.7 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1......................................................................................................... 37 Fig. 4.8 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2......................................................................................................... 37 Fig. 4.9 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3......................................................................................................... 38 Fig. 4.10 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4......................................................................................................... 38 Fig. 4.11 Typical transfer functions along vertical accelerometers arrays – EQ1........................ 39 Fig. 4.12 Vertical accelerations – EQ2 ......................................................................................... 39 Fig. 4.13 Stress-strain loops – EQ1 .............................................................................................. 40 Fig. 4.14 Stress-strain loops – EQ4 .............................................................................................. 40 Fig. 4.15 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation.............. 41 Fig. 4.16 Walls deformations obtained using a low pass filter – EQ1.......................................... 42 Fig. 4.17 Walls deformations obtained using a low pass filter – EQ4.......................................... 43 Fig. 4.18 Walls maximum deformations obtained using a low pass filter.................................... 44 Fig. 4.19 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1.................................................................................................................. 45 Fig. 4.20 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ4.................................................................................................................. 45 Fig. 4.21 Walls deformations obtained using a band pass filter – EQ4........................................ 46 Fig. 4.22 Walls maximum deformations obtained using a band pass filter.................................. 47 Fig. 4.23 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ3................................................................................................................ 48 Fig. 4.24 CPT test results.............................................................................................................. 48 Fig. 4.25 Soil surface settlements ................................................................................................. 49 Fig. 4.26 Test DRESBUS_2_2_1 model set up and instrumentation scheme.............................. 50 Fig. 4.27 Processed acceleration time histories – EQ1................................................................. 53 Fig. 4.28 Processed acceleration time histories – EQ2................................................................. 54 Fig. 4.29 Processed acceleration time histories – EQ3................................................................. 55 Fig. 4.30 Processed acceleration time histories – EQ4................................................................. 56 Fig. 4.31 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1......................................................................................................... 57 Fig. 4.32 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2......................................................................................................... 57 Fig. 4.33 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. – EQ3................................................................................................................ 58 Fig. 4.34 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4......................................................................................................... 58 Fig. 4.35 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation.............. 59 Fig. 4.36 Walls deformations obtained using a low pass filter – EQ2.......................................... 60 Fig. 4.37 Walls maximum deformations obtained using a low pass filter.................................... 61 Fig. 4.38 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ3.................................................................................................................. 62 Fig. 4.39 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ4................................................................................................................ 62
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Fig. 4.40 Walls maximum deformations obtained using a band pass filter.................................. 63 Fig. 4.41 CPT test results.............................................................................................................. 64 Fig. 4.42 Soil surface settlements ................................................................................................. 64 Fig. 4.43 Test DRESBUS_2_3_1 model set up and instrumentation scheme.............................. 65 Fig. 4.44 Processed acceleration time histories – EQ1................................................................. 68 Fig. 4.45 Processed acceleration time histories – EQ2................................................................. 69 Fig. 4.46 Processed acceleration time histories – EQ3................................................................. 70 Fig. 4.47 Processed acceleration time histories – EQ4................................................................. 71 Fig. 4.48 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1......................................................................................................... 72 Fig. 4.49 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2......................................................................................................... 72 Fig. 4.50 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3......................................................................................................... 73 Fig. 4.51 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4......................................................................................................... 73 Fig. 4.52 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation ............ 74 Fig. 4.53 Walls deformations obtained using a low pass filter – EQ1.......................................... 75 Fig. 4.54 Walls deformations obtained using a low pass filter – EQ4.......................................... 76 Fig. 4.55 Walls maximum deformations obtained using a low pass filter.................................... 77 Fig. 4.56 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ2.................................................................................................................. 78 Fig. 4.57 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ4................................................................................................................ 78 Fig. 4.58 Walls maximum deformations obtained using a band pass filter.................................. 79 Fig. 4.59 CPT test results.............................................................................................................. 80 Fig. 4.60 Soil surface settlements ................................................................................................. 80 Fig. 4.61 Test DRESBUS_2_4_2 model set up and instrumentation scheme.............................. 81 Fig. 4.62 Processed acceleration time histories – EQ1................................................................. 85 Fig. 4.63 Processed acceleration time histories – EQ2................................................................. 86 Fig. 4.64 Processed acceleration time histories – EQ3................................................................. 87 Fig. 4.65 Processed acceleration time histories – EQ4................................................................. 88 Fig. 4.66 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1......................................................................................................... 89 Fig. 4.67 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2......................................................................................................... 89 Fig. 4.68 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3......................................................................................................... 90 Fig. 4.69 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4......................................................................................................... 90 Fig. 4.70 Walls deformations obtained using a low pass filter – EQ2.......................................... 91 Fig. 4.71 Walls deformations obtained using a low pass filter – EQ4.......................................... 92 Fig. 4.72 Walls maximum deformations obtained using a low pass filter.................................... 93 Fig. 4.73 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1.................................................................................................................. 94 Fig. 4.74 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ1................................................................................................................ 94
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Fig. 4.75 Walls maximum deformations recorded by fork extensometers; low pass filter .......... 95 Fig. 4.76 Water pore pressures during and after shaking – EQ1 .................................................. 96 Fig. 4.77 Water pore pressures during and after shaking – EQ2 .................................................. 96 Fig. 4.78 Water pore pressures during and after shaking – EQ3 .................................................. 97 Fig. 4.79 Water pore pressures during and after shaking – EQ4 .................................................. 97 Fig. 4.80 CPT test results.............................................................................................................. 98 Fig. 4.81 Test DRESBUS_2_5_1 model set up and instrumentation scheme.............................. 99 Fig. 4.82 Processed acceleration time histories – EQ1............................................................... 102 Fig. 4.83 Processed acceleration time histories – EQ2............................................................... 103 Fig. 4.84 Processed acceleration time histories – EQ3............................................................... 104 Fig. 4.85 Processed acceleration time histories – EQ4............................................................... 105 Fig. 4.86 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1....................................................................................................... 106 Fig. 4.87 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2....................................................................................................... 106 Fig. 4.88 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3....................................................................................................... 107 Fig. 4.89 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4....................................................................................................... 107 Fig. 4.90 Walls deformations obtained using a low pass filter – EQ1........................................ 108 Fig. 4.91 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1................................................................................................................ 109 Fig. 4.92 Walls maximum deformations obtained using a low pass filter.................................. 110 Fig. 4.93 Walls maximum deformations obtained using a band pass filter................................ 111 Fig. 4.94 CPT test results............................................................................................................ 112 Fig. 4.95 Soil surface settlements ............................................................................................... 112 Fig. 4.96 Test DRESBUS_2_6_1 model set up and instrumentation scheme............................ 113 Fig. 4.97 Maximum Processed acceleration time histories – EQ1 ............................................. 116 Fig. 4.98 Processed acceleration time histories – EQ2............................................................... 117 Fig. 4.99 Processed acceleration time histories – EQ3............................................................... 118 Fig. 4.100 Processed acceleration time histories – EQ4............................................................. 119 Fig. 4.101 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1....................................................................................................... 120 Fig. 4.102 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2....................................................................................................... 120 Fig. 4.103 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3....................................................................................................... 121 Fig. 4.104 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4....................................................................................................... 121 Fig. 4.105 Walls deformations obtained using a low pass filter – EQ1...................................... 122 Fig. 4.106 Walls maximum deformations obtained using a low pass filter................................ 123 Fig. 4.107 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1................................................................................................................ 124 Fig. 4.108 Walls maximum deformations obtained using a band pass filter.............................. 125 Fig. 4.109 Water pore pressures during and after shaking – EQ1 .............................................. 126 Fig. 4.110 Water pore pressures during and after shaking – EQ2 .............................................. 126 Fig. 4.111 Water pore pressures during and after shaking – EQ3 .............................................. 127 Fig. 4.112 Water pore pressures during and after shaking – EQ4 .............................................. 127
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Fig. 4.113 Soil surface settlements ............................................................................................. 128 Fig. 4.114 Test DRESBUS_2_7_1 model set up and instrumentation scheme.......................... 129 Fig. 4.115 Processed acceleration time histories – EQ1............................................................. 132 Fig. 4.116 Processed acceleration time histories – EQ2............................................................. 133 Fig. 4.117 Processed acceleration time histories – EQ3............................................................. 134 Fig. 4.118 Processed acceleration time histories – EQ4............................................................. 135 Fig. 4.119 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1....................................................................................................... 136 Fig. 4.120 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2....................................................................................................... 136 Fig. 4.121 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3....................................................................................................... 137 Fig. 4.122 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4....................................................................................................... 137 Fig. 4.123 Walls deformations obtained using a low pass filter – EQ1...................................... 138 Fig. 4.124 Walls maximum deformations obtained using a low pass filter................................ 139 Fig. 4.125 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1................................................................................................................ 140 Fig. 4.126 Walls maximum deformations obtained using a band pass filter.............................. 141 Fig. 4.127 Water pore pressures during and after shaking – EQ1 .............................................. 141 Fig. 4.128 Water pore pressures during and after shaking – EQ2 .............................................. 142 Fig. 4.129 Water pore pressures during and after shaking – EQ3 .............................................. 142 Fig. 4.130 Water pore pressures during and after shaking – EQ4 .............................................. 143 Fig. 4.131 Soil surface settlements during swing up .................................................................. 143 Fig. 4.132 Soil surface settlements during shaking .................................................................... 144 Fig. 5.1 CPT test results for the dry sand tests............................................................................ 145 Fig. 5.2 Maximum horizontal acceleration at the soil free field (Array 2) for the dry tests....... 146 Fig. 5.3 Maximum horizontal acceleration at the soil free field (Array 2) for the saturated tests..................................................................................................................................................... 147 Fig. 5.4 Maximum racking deformations for different input motion amplitudes – rough flexible tunnel in dry sand (DRESBUS2_1_1) ........................................................................................ 148 Fig. 5.5 Maximum racking deformations for different input motion amplitudes – smooth flexible tunnel in dry sand (DRESBUS2_2_1) ........................................................................................ 148 Fig. 5.6 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in dry sand (DRESBUS2_3_1) ........................................................................................ 149 Fig. 5.7 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in saturated sand (DRESBUS2_4_2) ............................................................................... 149 Fig. 5.8 Maximum racking deformations for different input motion amplitudes – smooth rigid tunnel in dry sand (DRESBUS2_5_1) ........................................................................................ 150 Fig. 5.9 Maximum racking deformations for different input motion amplitudes – smooth rigid tunnel in saturated sand (DRESBUS2_6_1) ............................................................................... 150 Fig. 5.10 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in saturated sand (DRESBUS2_7_1) ............................................................................... 151 Fig. 5.11 Maximum racking deformations for different input motion amplitudes – rough vs. smooth flexible tunnel in dry sand (DRESBUS2_1_1 vs. DRESBUS2_2_1)............................ 152 Fig. 5.12 Maximum racking deformations for different input motion amplitudes – rough vs. smooth rigid tunnel in saturated sand (DRESBUS2_6_1 vs. DRESBUS2_7_1) ....................... 153
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Fig. 5.13 Maximum racking deformations for different input motion amplitudes – effect of sand saturation (DRESBUS2_3_1 vs. DRESBUS2_7_1)................................................................... 154
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List of Tables
Table 2.1 Scaling laws for geotechnical centrifuge tests (Schofield, 1980)................................... 4 Table 2.2 Fontainebleau sand NE 34 physical properties.............................................................. 4 Table 2.3 Mechanical properties of the aluminum alloy used ........................................................ 7 Table 2.4 Tunnels flexibility ratios based on Wang (1993) method............................................... 8 Table 2.5 Pouring parameters ....................................................................................................... 10 Table 2.6 Calibration parameters of the fork systems .................................................................. 18 Table 2.7 Calibration curves for the diagonal extensometers....................................................... 22 Table 2.8 DRESBUS II testing program....................................................................................... 22 Table 2.9 Extensometer systems used during each test ................................................................ 23 Table 2.10 Input motions characteristics (bracketed values: values in prototype scale) .............. 24 Table 4.1 Sensors numbering and exact positions ........................................................................ 29 Table 4.2 Extensometers numbering............................................................................................. 30 Table 4.3 Sensors numbering and exact positions ........................................................................ 51 Table 4.4 Extensometers numbering............................................................................................. 52 Table 4.5 Sensors numbering and exact positions ........................................................................ 66 Table 4.6 Extensometers numbering............................................................................................. 67 Table 4.7 Sensors numbering and exact positions ........................................................................ 82 Table 4.8 Extensometers numbering............................................................................................. 83 Table 4.9 Measured vs. theoretical water pore pressure at P1...................................................... 84 Table 4.10 Sensors numbering and exact positions .................................................................... 100 Table 4.11 Extensometers numbering......................................................................................... 101 Table 4.13 Sensors numbering and exact positions .................................................................... 114 Table 4.14 Extensometers numbering......................................................................................... 115 Table 4.12 Sensors numbering and exact positions .................................................................... 130 Table 4.13 Extensometers numbering......................................................................................... 131
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1 Introduction
Large underground structures such as tunnels and metro stations possess a vital socio-economic
role being a crucial part of the transportation and utility networks in an urban area. The
associated impact in case of earthquake induced damages denotes the paramount importance of a
safe seismic design, especially in seismically active areas.
Although recent earthquake events (Kobe 1995, Duzce 1999, Chi-Chi 1999 and Wenchuan 2008)
have demonstrated that underground structures may undergo extensive deformations or even
collapse (Sharma and Judd, 1991, Wang, 1993, Iida et al., 1996 among others), their seismic
response has been little explored compared to aboveground structures due to lack of
experimental data and well-documented field evidence (Cilingir and Madabhushi, 2011). In this
regard, design specifications for underground structures in modern seismic codes are based
primarily on simplified methods (Wang, 1993, Penzien, 2000, Hashash et al., 2001, ISO 23469,
2005, FWHA, 2009), the implementation of which may lead to a substantially different seismic
design for this type of structures (Pitilakis and Tsinidis, 2012).
A substantial contribution to the knowledge of seismic behavior of underground structures may
be accomplished by means of well-focused experimental data, allowing investigation of crucial
response parameters such as seismic earth pressures distribution on the side walls of the
structure, seismic shear stresses distribution around the perimeter of the structure and definition
of impedance functions to be implemented in simplified Winkler models for underground
structures.
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(a)
(b)
Fig. 1.1 Daikai Station. (a) Settlements of the overlaying roadway caused by the subway collapse, (b) Collapse of the central columns of the station (Special Issue of Soil and
Foundations, 1996)
The above research objectives motivated the realization of the collaborative experimental
Transnational Access project DRESBUS II “Investigation of the seismic behavior of shallow
rectangular underground structures in soft soils using centrifuge experiments” offered by the
SERIES research project. More specifically, DRESBUS II TA project dealt with the
investigation of shallow rectangular tunnels seismic response by means of dynamic centrifuge
testing. The experimental study was elaborated in the geotechnical centrifuge facility of
IFSTTAR under a centrifuge acceleration of 40g. Well-documented experimental data was
recorded for a wide set of soil-tunnel systems allowing a better understanding of the seismic
behavior of underground structures, as affected by salient parameters such as soil-structure
relative flexibility, soil-tunnel interface properties, soil saturation and amplitude of excitation.
Following a detailed description of DRESBUS II project set up, the herein report provides (a) a
representative set of experimental recordings obtained from each centrifuge test case and (b)
comparisons between selected soil-tunnel systems to highlight important aspects of the physical
problem within a preliminary interpretation of the recorded data.
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2 DRESBUS II experimental program
2.1 IFSTTAR CENTRIFUGE FACILITY
DREBSUS II TA project was hosted by the centrifuge facility of IFSTTAR in Nantes, France.
IFSTTAR centrifuge has a radius of 5.5m and a capacity of two tonnes under a centrifugal
acceleration of 100g. The dimensions of the swinging basket supporting the model are 1.4m ×
1.1m.
Earthquake input motions were applied at the base of the soil-tunnel model, using the specially
designed actuator Actidyn QS 80 (Chazelas et al., 2008) being able to impose both sinusoidal
and real record input motions up to 400kg of payload mass. It is designed to work under a
centrifugal acceleration up to 80g, while it can apply input motions of peak acceleration at 0.5g,
allowing modeling of a wide frequency range (30-300Hz for real earthquakes).
A large Equivalent Shear Box (ESB) was employed to mount the models, having inner
dimensions 800mm in length, 340mm in width and 409mm in depth. The box is designed to
match the shear stiffness of the contained soil for the range of shear strains of interest, in order to
minimize spurious boundary effects arising from soil-container interactions.
Fig.2.1 (a) Geotechnical Centrifuge at IFSTTAR, (b) Earthquake Actidyn QS 80 actuator, (c) ESB container
(a) (b) (c)
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2.2 CENTRIFUGE SCALING LAWS
The tests were performed under a centrifuge acceleration of 40g, implying a scaling factor at
1/40 (N = 40). As the centrifuge gravity is not constant with depth, the reference level for the
tuning of the centrifuge acceleration (40 g) was defined at the bottom soil-tunnel interface. The
relevant parameters are scaled down to the model level following standard scaling laws for
centrifuge testing (Table 2.1).
Table 2.1 Scaling laws for geotechnical centrifuge tests (Schofield, 1980)
Parameter Dimensions (*) Model / Prototype Length L 1/N Mass M 1/N3 Stress ML-1T-2 1 Strain 1 1 Force MLT-2 1/N2
Time (dynamic loading) T 1/N Time (Seepage) T 1/N2
Frequency 1/T N Acceleration LT-2 N
Velocity LT-1 1 Seepage Velocity LT-1 N
Displacement L 1/N *where: L is the length, T is the time, M is the mass and N is the scaling factor
2.3 FONTAINEBLEAU SAND PROPERTIES
Soil deposit was composed by Fontainebleau sand NE34 D50 = 200 μm, with a relative density at
70%. The main physical properties of the sand are summarized in Table 2.2.
Table 2.2 Fontainebleau sand NE 34 physical properties
ρs (g/cm3) emax emin d50 (mm)
Fontainebleau sand NE34 2.64 0.86 0.55 0.200
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2.4 TUNNEL MODELS
2.4.1 Models dimensions
Models dimensions were specifically chosen on the basis of reflecting desirable soil-to-tunnel
relative flexibility and interface characteristics. Four model sections were manufactured and
tested referring to a rigid section with a rough interface, a rigid section with a smooth interface, a
flexible section with a rough interface and a flexible section with a smooth interface,
respectively.
Models sections are shown in Fig. 2.2. The inside dimensions of the models were kept constant
allowing use of identical extensometers (described in the ensuing). Based on the scaling factor
employed (N=40), the flexible tunnel models correspond to 1.88 × 2 (m) sections having an
equivalent concrete thickness equal to 8 cm for the walls and 32 cm for the slabs in prototype
scale (assuming E = 30 GPa for the concrete). Accordingly, the rigid tunnel models correspond
to 2.16 × 2 (m) sections having an equivalent concrete thickness equal to 27 cm for the walls and
30 cm for the slabs.
6mm
6mm 1.5mm
1.5mm50mm
47mm
Model 1
50mm
Model 2
54mm
6mm
5mm
6mm
5mm
Fig. 2.2 Tunnels sections
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2.4.2 Soil‐tunnel interface rugosity
The tunnel sections were manufactured from 2017 A aluminum alloy (equivalent to old reference
AU4G T4), by implementing an electro-erosion technique to avoid any manufacturing or
assembly pre-stressing.
Referring to soil-tunnel interface rugosity two cases were investigated: (i) a smooth interface and
(ii) a rough interface, by changing the models external face roughness. Roughness is defined by
(Figs. 2.3 and 2.4):
0
1( )
L
aR f x dxL
(2.1)
0
1²( )
L
qR f x dxL
(2.2)
where Ra refers to an algebraic mean of the relief height around a mean line (grooves height) and
Rq, stands for a quadratic mean of the relief height around a mean line. Referring to the tunnel
sections with a rough soil-tunnel interface, (R) and (AR) were set at 100μm and 200μm,
respectively.
Fig. 2.3 Definition of roughness
Fig. 2.4 Relation between the sand grain size and the grooves dimensions
AR
R
AR
R
AR
R
Rt
L
f(x)
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2.4.3 Aluminium mechanical properties
The elastic modulus of the specific fraction of aluminum was back-calculated from a series of
deformation tests performed on small length pieces of the tunnel models (3 cm). A specially
designed device was employed for these tests (Fig. 2.5), consisting of two brackets, connected
with each other, through the tunnel specimen. The top bracket was fixed, while the bottom was
supporting a plate to introduce the masses producing a tensional load to the model. The diagonal
deformation of the model was measured by two LVDTs (black cylinders in Fig. 2.5). The loads
(masses) were incrementally increased, reaching to a diagonal deformation equal to 1 mm.
Several circles of loading and uploading were conducted to examine the reversibility of the
phenomenon and to make sure that no hysteresis loops were observed. For the back analysis the
system was numerically modeled implementing an elastoplastic constitutive law, assuming a
yield stress at 400 MPa. The elastic modulus was calibrated based on the recorded deformations.
The metal stirrups were considered to be elastic (E=200 GPa), while the friction coefficient
between the stirrups and the model was assumed equal to 0.3. The comparisons indicated an
elastic modulus equal to 71 GPa. Table 2.3 summarizes the mechanical properties of the
aluminum alloy.
Fig. 2.5 Device for the deformation tests of the tunnel specimens
Table 2.3 Mechanical properties of the aluminum alloy used
Elastic modulus (GPa) 71 Poisson v 0.33
Yield stress (MPa) 400 Density (t/m3) 2.7
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2.4.4 Flexibility ratios
Mention has already been made to the variable of tunnel stiffness employed in the centrifuge
experiments. The above parameter was quantified by means of the soil-tunnel flexibility ratio as
reported in Wang (1993). According to this simplified procedure, the flexibility ratio for
rectangular tunnels is estimated as:
mG WF
S H
(2.3)
where, Gm is the soil shear modulus, W is the width of the structure, H is the height of the
structure and S is the required force to impose a unit racking deflection of the structure. The
latter can be estimated through a simple static frame analysis of the tunnel. Soil shear modulus
was estimated herein, according to the Hardin and Drenvich (1972) model (Fig. 2.6), leading to
the flexibility ratio values that are summarized in Table 2.4.
‐14.4
‐10.8
‐7.2
‐3.6
0
0 100 200 300 400Vs (m/s)
z(m)
Saturated sand Dry sand
Fig. 2.6 Small strain shear wave velocity profiles according to Hardin and Drenvich model
Table 2.4 Tunnels flexibility ratios based on Wang (1993) method
Tunnel model Saturated sand Dry sand model-1 (flexible tunnel) 14.7 11.6
model-2 (rigid tunnel) 0.72 0.55
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2.5 MODELS PREPARATION
An automatic hopper system was employed to form the sandy soil deposit of the centrifuge
models in a piecewise manner. During model formation, tunnel section and recording devices
were embedded at the desirable locations (Fig. 2.7).
2.5.1 Sand pouring
The device implemented for sand pouring is a linear curtain hopper that moves automatically
back and forth over the experimental container. A slot at the bottom of the hopper is actually
forming the sand curtain. The tuning parameters for a given (desirable) density are:
the width of the slot,
the falling height (distance between the sand layer and the hopper slot)
the movement velocity of the device and
the number of back and forth journeys over the container before changing the hoppers
height.
These tuning parameters were accordingly selected (Table 2.5) to achieve the desirable soil
density at 70%.
Fig. 2.7 Model preparation
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Table 2.5 Pouring parameters
Sand type
Slot (mm)
Falling height (cm)
Horizontal frequency
(Hz)
Height tuning
ID (%)
γd
(kN/m3)
Fontainebleau sand NE34
4 60 32 Every two back
and forth journeys 70 15.82
2.5.2 Saturation procedure
During shaking, the water pore pressures in a granular soil increase. These pore pressures will
slowly decrease after the earthquake as water will dissipate within the soil from high- to low-
pressure subsoil regions. The above dissipation mechanism is governed by the Darcy’s law. To
respect the similitude laws for both the fundamental equation of the dynamics and the Darcy’s
law, viscous liquid is preferred rather than water. In centrifuge experiments it is common to add
Hydroxy-methyl-propylcellulose (HPMC) into water to obtain a liquid of viscosity N times
higher than water, with N being the reduction factor of the experiment (.e.g. N = 40). The HPMC
quantity is usually negligible (around 2%) so that the density of water is not changing. The above
technique is quite efficient as it can easily be implemented and has a low cost. However, the
water-HPMC mixture has some drawbacks. The viscosity of the mixture is temperature-
depended and it is affected by the development of bacteria. Moreover, the mixture is not
completely Newtonian as the viscosity is slightly depending on the velocity of the flux. To avoid
the development of bacteria, an antiseptic additive (2 to 4 % of the HPMC) is used. As the
preparation of a soil bed can take 10 to 15 days (pluvation, saturation, delay for centrifuge
availability, final set up) the weather conditions must be accounted. Although the liquid viscosity
may not affect the soil behavior during shaking (undrained conditions), it affects the time of the
pore pressures dissipation and should therefore be taken into account.
To avoid any water leakage from the sides of the ESB container, a waterproof rubber membrane
was installed on the container walls. In order to flatten the membrane against the box walls an
additional jacket was added at the external face of the container and a partial void was applied
between jackets. During the saturation phase, a lid was added on top of the box, over the jackets,
and the liquid (water of increased viscosity) was injected by the bottom plate of the box. The
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saturation of the whole soil deposit was made under a partial vacuum. The whole procedure was
controlled by specially designed software. The saturation process is summarized in the following
steps:
The liquid mixture for the saturation is prepared diluting about 2% of Hydroxy – Propyl –
Methyl – Cellulose (HPMC) into water. The mixture is then sterilized with antiseptic (~6%
of HPMC) and de-aired for 8 hours in a tank under a partial vacuum decreased progressively
to 0.2 bars.
The sand deposit in the ESB container is put under 0.3 bar vacuum for 3 hours.
Then the atmospheric pressure is restored by injection of CO2 for 10 minutes and
subsequently the vacuum is restored.
The bottom level of the tank is set 30 cm higher than the bottom plate of the ESB container
to fill the capillarity layer with the liquid. This procedure takes about 12 hours.
To fill the whole sand model, the level of the tank is consecutively adjusted so that the water
level in the tank is 30 cm over the water level in the ESB container. This difference is
maintained by a control system. Approaching the sand surface, the height difference is
reduced progressively to avoid under-pressure on the surface sand grains.
The saturation procedure continues until the water table reaches 2 cm over sand surface.
Fig. 2.8 Installation of the waterproof rubber membrane on the ESB container
Jacket vacuum pump
1 bar
Metallic flanges
1 bar
0.2 bar Wooden protection of membrane
External jacket Internal jacket
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Fig. 2.9 Schematic representation of the saturation system setup
Fig. 2.10 Saturation system setup
2.5.3 Treatment of model tunnels boundaries
The tunnels ends were properly designed to ensure a plain strain model behavior. For this reason,
low friction Teflon plates were glued on the ESB container in the case of dry sand (Fig. 2.12a).
The tunnel ends were equipped with knobs made of soft rubber foam. An aluminum plate was
stuck on the external face of the knob being in contact with the Teflon plate. In this manner the
foam knob could be compressed without limiting the in plane deformation of the tunnel near its
ends.
Jacket vacuum pump
1 bar
0.2 bar
Box & Tank Vacuum Pump
Float and magnetic water level gauge
Table height gauge
CO2
Sand saturation set up
Table height motor
0.3 bar
Float and magnetic water level gauge
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Fig. 2.11 Typical connection of the tunnel with the ESB box for the dry sand tests
Tunnel
Soft rubberfoam
Aluminum plate
Teflon plate
ESB container aluminum frame
ESB containerrubber layer
Tunnel
Soft rubberfoam
Aluminum plate
Teflon plate
ESB container aluminum frame
ESB containerrubber layer
Soft rubberplate
Waterproof rubbermembrane
Tunnel
Soft rubberfoam
Aluminum plate
Teflon plate
ESB container aluminum frame
ESB containerrubber layer
PVC cap
Waterproof rubbermembrane
Soft silicon joint
(a) (b)
(c)
Fig. 2.12 Details of the tunnels – ESB box connections (a) Dry sand tests, (b) Saturated sand tests; first solution, (c) Saturated sand tests; final solution
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For the test cases with saturated sand a thin rubber membrane covering the inside of the ESB
container was employed to waterproof the box. The Teflon plates were glued on this membrane
using double face tape. The foam cap was modified to glue a soft rubber plate on the tunnel slabs
and walls ends. The principle of the compressible foam was kept to contribute to the link
between this rubber layer and the aluminum of the tunnel (Fig. 2.12b). Unfortunately, this set up
did not manage to resist the water pressure, leading to water leakage inside the tunnel for a test
case (DRESBUS2_4_1). The connection was then redesigned to resist both positive and negative
relative pressures, since at those locations the pressures were significantly changing during
model construction and experiment. A stronger PVC cap was stuck on the tunnel using a thick
soft silicone joint resisting positive and negative pressures, thus limiting slightly the tunnel
deformations (Fig. 2.12c). The effect of this limitation was checked by diagonal extensometers
installed at the middle and the end sections of the tunnel-models.
All the strain gauges wires were settled inside the tunnel model and exited near the extremity of
the model through the top slab.
2.6 MODEL LAYOUT ‐ INSTRUMENTATION SCHEME
Fig. 2.13 and 2.14 present typical model layouts of the centrifuge tests referring to a dry and a
saturated sand case, respectively. A particularly dense instrumentation scheme was designed and
installed to record soil-tunnel response comprising of miniature piezoelectric accelerometers in
vertical arrays within the soil or attached to the tunnel section and the ESB container,
displacement sensors to record the surface ground settlement and pore pressure sensors to
measure pore pressure dissipation, for the saturated cases. Furthermore, specially designed
extensometers were used to record the racking deformations of the tunnel section and diagonal
“blade” extensometers were installed along the longitudinal axis of the tunnel to verify the
homogeneity of deformation and control out of plane response of the structure.
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250mm
400mm240mm
360mm
180mm326mm
355mm
A2
A1
A3
A4
A20
A12
A9 A6 A13A7
A10A11
A8 A5
130mm
125mm
A14A15
20mm
100mm
A23
A24
A21
A22
A25A26F5
F1F5
F10
D1 D2D3
D4
S1 S3
800mm
Dry Fontainebleau Sand(Dr=70%)
50mm
47mm
Model
14mm
y
x
z
S2
Accelerometer Laser displacementsensor
Diagonal extensiometer Transversal "fork"extensiometer
1.5mm6.0mm
A16
A17
A18A19
Fig. 2.13 Typical model layout for a dry test
2.6.1 Miniature accelerometers
Miniature piezoelectric accelerometers were used to measure the acceleration in the soil, on the
tunnel and on the ESB box. The transducers were installed in vertical arrays within the soil to
capture base-to-surface amplification of soil response in the horizontal direction and the tunnel
effect on the induced wave field.
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250mm
400mm240mm
360mm
180mm326mm
360mm
A2
A1
A3
A4
A20
A12
A9 A6 A13A7
A10A11
A8 A5
130mm
130mm
A14A15
20mm
100mm
F5
F1F6
F10
D1 D2D3
D4
S1 S3
800mm
Dry Fontainebleau Sand(Dr=70%)
Model
14mm
y
x
z
S2
Accelerometer Laser displacement sensor
Diagonal extensiometer
Transversal "fork"extensiometer
50mm
5.0mm6.0mm54mm
A23
A24
A21
A22
A25A26
A16
A17
A18A19
Pore pressuresensor
A27
P3P1
P2 P4 P5
P6
Fig. 2.14 Typical model layout for a saturated test
2.6.2 Displacement sensors
Soil surface settlements were measured by displacement sensors installed at three locations along
the ground surface. Laser sensors were used for the dry sand tests, while potentiometer sensors
were used for the saturated tests, as the water table was set above the soil surface (2cm above).
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2.6.3 Pore pressure cells
For the saturated tests pore pressure cells were utilized, to measure the water pore pressures at
several locations near the tunnel and at the free field during and after shaking.
The final positions of the instruments (accelerometers, pore pressure cells) were defined during
installation as well as after the test to measure the actual soil settlement caused by the centrifuge
spin up and the subsequent shaking.
2.6.4 Walls deformations extensometers
The tunnel-models deformations were measured in terms of side-walls deformations at the
middle section and diagonal deformations of the model at several locations. For this purpose,
special designed extensometers were installed.
To determine and measure the racking deformations of the tunnels side-walls a special device
was designed, comprising of 2x5 “teeth”, capable of measuring, independently, the deformations
of the walls relatively to the bottom slab. The device was fixed at the middle section of the invert
slab of the tunnel. Fig. 2.15 displays one of these extensometer devices. Each “tooth” is equipped
with two strain gauges mounted in half-bridge, forming a bending deformation sensor. These
sensors can measure deformations up to 1 mm, and withstand a force up to 10N, without
yielding. The design sheet with the main characteristics of this system is given in Fig. 2.16.
A special mechanical system was used for the calibration of these sensors (Fig. 2.17). During the
calibration procedure, each tooth was plugged to the system and subjected to 2 mm
displacement, controlled be a micrometer. The calibration curves denote linear response, with a
different offset. Table 3.5 summarizes the corresponding calibration factors.
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Fig. 2.15 “Fork” system extensometer
Table 2.6 Calibration parameters of the fork systems
Fork system 1
a mm/mmV
b mm/mmV
Fork system 2
a mm/mmV
b mm/mmV
Fork system 3
a mm/mmV
b mm/mmV
Fork 1-1 0.352 0.1754 Fork 2-1 0.345 -0.189 Fork 3-1 0.361 -0.115 Fork 1-2 0.348 0.187 Fork 2-2 0.347 -0.138 Fork 3-2 0.367 -0.197 Fork 1-3 0.355 0.116 Fork 2-3 0.347 -0.167 Fork 3-3 0.364 -0.028 Fork 1-4 0.349 0.083 Fork 2-4 0.348 -0.182 Fork 3-4 0.363 -0.283 Fork 1-5 0.358 -0.164 Fork 2-5 0.347 0.062 Fork 3-5 0.368 -0.178 Fork 1-6 0.358 -0.112 Fork 2-6 0.346 -0.131 Fork 3-6 0.389 -0.220 Fork 1-7 0.353 -0.232 Fork 2-7 0.351 -0.204 Fork 3-7 0.366 -0.264 Fork 1-8 0.363 -0.050 Fork 2-8 0.350 0.017 Fork 3-8 0.367 -0.156 Fork 1-9 0.355 -0.416 Fork 2-9 0.349 -0.089 Fork 3-9 0.369 -0.357
Fork 1-10 0.351 -0.142 Fork 2-10 0.347 -0.316 Fork 3-10 0.369 -0.041
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Fig. 2.16 Design sheet of the fork extensometers
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Fig. 2.17 Calibration device for the fork extensometers - Representative calibration curves of a fork system
2.6.5 Diagonal extensometers
To measure diagonal deformations and control the plain strain behavior of the tunnel, diagonal
extensometers were installed at several locations along the longitudinal axis of the models. These
sensors are made of a pre-stressed steel blade, forming an arch in the diagonal of the rectangular
section of the tubes. They are equipped with strain gauges mounted in half bridges placed at mid
span to evaluate the deformation of the arch. The main design characteristics of the sensors are
conforming to the following limitations:
the lateral walls can have a displacement equal to 1 mm, so the diagonal can range from
58.14 mm to 59.67 mm.
the force applied by the extremities of the extensometers to the tubes should be limited to
10N.
Fig. 2.18 Diagonal extensometers
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Fig. 2.19 Design sheet for the diagonal extensometers
For the calibration of these sensors, a specific device was designed (Fig. 2.20). During the
calibration the extensometer is stressed until the cord length is equal to the diagonal of the tunnel
at rest. Displacement steps are then imposed with a micrometer to obtain ± 1.25 mm around the
original position. Although the response shown in Fig. 2.20 is not linear, a similar trend is
obvious between the different extensometers tested. To this end, it was concluded that a fourth
degree polynomial fits better the specific calibration curves.
Fig. 2.20 Calibration device for the diagonal extensometers
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Table 2.7 Calibration curves for the diagonal extensometers
Regression law – Chord length = f(x in mV) CL 1 to 4 4 3 2y 0.1231x 0.2434x 0.3237x 2.6624x 8.637
CL 5 to 8 4 3 2y 0.0784x 0.2153x 0.4352x 2.6842x 9.3893
CL 9 to 12 4 3 2y 0.0965x 0.2222x 0.4134x 2.68x 8.9683
2.7 TESTING PROGRAM
Seven centrifuge tests were carried out in total, by combining flexible or rigid tunnel sections,
smooth or rough soil-tunnel interface and dry or saturated sand. The test cases are tabulated in
Table 2.8. It is noted that Dresbus_2_4_1 test failed due to water leakage inside the tunnel. Table
2.9 summarizes the extensometer systems used for each test.
Table 2.8 DRESBUS II testing program
Test case
# Test name
Structure flexibility
Soil Dr (%)
Soil saturation
Culvert surface
Test month
1 Dresbus_2_1_1 Flexible Dry Rough April 2012 2 Dresbus_2_2_1 Flexible Dry Smooth May 2012 3 Dresbus_2_3_1 Rigid Dry Rough July 2012 4* Dresbus_2_4_1 Rigid Saturated Rough July 2012 5** Dresbus_2_4_2 Rigid Saturated Rough December 2012 6 Dresbus_2_5_1 Rigid Dry Smooth August 2012 7 Dresbus_2_6_1 Rigid Saturated Smooth October 2012 8 Dresbus_2_7_1 Rigid
70
Saturated Rough October 2012 * failed
** repetition test of Dresbus_2_7_1 to check the repeatability
2.8 EXPERIMENTAL PROCEDURE
During each flight, the centrifuge was spun up to 40g and swing down to 1g three times
(consolidation – stabilization circles) to check the proper function of the monitoring scheme.
Once the consolidation cycles completed, a CPT test was conducted at a surface location away
from the tunnel (Fig. 2.22). During the main dynamic tests, acceleration, tunnel deformations and
pore pressures data were firstly recorded at a sampling frequency of 51 kHz and were then re-
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sampled at 12.8 kHz by means of a fast acquisition system that is available at IFSTTAR (DAS).
Soil surface settlements were recorded at a lower sampling frequency.
Table 2.9 Extensometer systems used during each test
Test case
# Test name
Fork system
Diagonal extensometers
1 Dresbus_2_1_1 F3 CL5-8 2 Dresbus_2_2_1 F3 CL5-8 3 Dresbus_2_3_1 F3 CL5-8 4 Dresbus_2_4_1 F2 CL9-12 5 Dresbus_2_4_2 F2 CL9-12 6 Dresbus_2_5_1 F2 CL9-12 7 Dresbus_2_6_1 F2 CL9-12 8 Dresbus_2_7_1 F2 CL9-12
Fig. 2.21 Shaking table base configuration
Fig. 2.22 Relative position of the CPT with respect to the tunnel (top view)
Tunnel
CPT
~ 37 cm
22 cm
13 cm
Tunnel
Sand
Container
Centrifuge pivot side
Shaking table
Centrifuge room door side
DAS
X
Y
Z
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2.9 INPUT MOTION CHARACTERISTICS
Four input motions were successively introduced at the base of the model referring to a record
from the Northridge earthquake (1994) scaled to 0.1 g, 0.2 g and 0.3 g peak acceleration
followed by sine wavelet having a frequency equal to 85 Hz and an amplitude equal to 0.3 g
(Table 2.10 and Fig. 2.23).
0 0.25 0.5 0.75 1−0.35
−0.175
0
0.175
0.35
t(s)
A/4
0g
EQ1
0 0.25 0.5 0.75 1−0.35
−0.175
0
0.175
0.35
t(s)
A/4
0gEQ2
0 0.25 0.5 0.75 1−0.35
−0.175
0
0.175
0.35
t(s)A
/40g
EQ3
0 0.16 0.32 0.48 0.64−0.35
−0.175
0
0.175
0.35
t(s)
A/4
0g
EQ4
Fig. 2.23 Nominal input motions
Table 2.10 Input motions characteristics (bracketed values: values in prototype scale)
Nominal amplitude (g) Nominal Duration (s)
Input type Model scale Prototype scale Model scale Prototype scale
EQ1 4.0 0.10 1.0 40 EQ2 8.0 0.20 1.0 40 EQ3
Northridge record 12.0 0.30 1.0 40
EQ4 Pseudo-Harmonic
(85Hz) 12.0 0.30 0.64 25.6
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3 Data processing
3.1 ACCELERATIONS
Filtering – Displacements computation
The acceleration-time histories were band-pass filtered between 20 to 400 Hz (model scale),
before double integrating them to obtain the corresponding displacement signals. Using the
filtered data, the maximum horizontal acceleration was computed for all the locations and plotted
along vertical acceleration arrays (i.e. free field array, tunnel array etc).
Transfer functions
To identify possible soil-structure interaction and wave field effects, pertinent transfer functions
were computed by utilizing available recordings along vertical arrays within the centrifuge
apparatus. Based on the corresponding Fourier spectra soil amplification is defined by the ratio:
1
2
TF
(3.1)
where 1 and 2 refer to the Fourier spectra of the two recordings.
Shear strain-stress loops
Having computed the displacement time histories, shear strains may be evaluated by means of
the procedure proposed by Zeghal and Elgamal (1994) as reported in Brennan et al. (2005) for
centrifuge testing. More specifically, using a first order approximation, shear strain between two
instruments in the same vertical array is:
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2 1
2 1
u u
z z
(3.2)
According to the above procedure, the shear stress τ may be computed from the integration of the
acceleration time histories with respect to depth z:
0
zz a z dz (3.3)
Alternatively, the following simplified formulation may be adopted:
10
2z z u u z (3.4)
For surface acceleration, a linear fit was performed, using the adjacent pair of instruments
(Brennan et al., 2005).
2 1
1 12 1
u uu z u z z
z z
(3.5)
Having the shear strain and the shear stress, soil shear stiffness was estimated for each τ-γ loop
by means of (Brennan et al., 2005):
max min
max min
G
(3.6)
where τmax, τmin, γmax, γmin correspond to the maximum and minimum shear stress and strain,
respectively, in each loop. Shear wave propagation velocity may then be estimated through
standard elastodynamic considerations.
sV G (3.7)
with ρ being the sand density.
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3.2 EFFECT OF FILTERING TECHNIQUE ON TUNNEL DISTORTION RECORDINGS
Residual values of deformation recorded in some tests should be attributed to sensor drifts during
shaking and to some minor extend to permanent response due to the soil yielding and
densification. Using a band pass filter those permanent values are vanished. However, if a low
pass filter is adopted, these residual values are not minimized. For this reason, both a band pass
(20-400 Hz) and a low pass filters (400Hz) were used to obtain relevant comparisons with the
numerical analyses. An 8th order Butterworth type was employed for both filtering schemes.
3.3 WATER PORE PRESSURES
The pore pressures time histories were filtered using a 8th order Butterworth type low pass filter
for frequencies up to 400 Hz (in model scale).
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4 Experimental data
4.1 TEST DRESBUS_2_1_1
Fig. 4.1 presents the model set up along with instrumentation scheme.
DRESBUS2_1_1: Flexible tunnel ‐Rough surface ‐ Dry Sand
250mm
400mm240mm
360mm
180mm326mm
355mm
A2
A1
A3
A4
A20
A12
A9 A6 A13A7
A10A11
A8 A5
130mm
125mm
A14A15
20mm
100mm
A23
A24
A21
A22
A25A26F5
F1F5
F10
D1 D2D3
D4
S1 S3
800mm
Dry Fontainebleau Sand(Dr=70%)
50mm
47mm
Model14mm
y
x
z
S2
Accelerometer Laser displacementsensors
Diagonal extensiometer Transversal "fork"extensiometer
1.5mm6.0mm
A16
A17
A18A19
Fig. 4.1 Test DRESBUS_2_1_1 model set up and instrumentation scheme
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Tables 4.1 and 4.2 summarize channels and sensors locations before and after the main test. The
coordinates refer to the reference system presented in Fig. 2.21. The settlements estimated for
each instrument by the direct measurements are also reported.
Table 4.1 Sensors numbering and exact positions
Real coordinates at set-up
Real Position after shocksA/A
DAS Channel
Sensor #
Position Positive Direct X
cm Y
cm Z / top box
cm Z / surface
cm Z / top box
cm Settlement
cm A1 1 68 End table + pivot A2 2 69 Bottom plate + pivot 17 40 A20 3 79 Bottom plate +top A3 4 73 Above plate + pivot 16.5** 40 39.6 34.1 39.6 0 A4 5 96 +13 cm/bottom + pivot 16.5** 40 28.1 22.6 28.1 0 A12 6 74 +13 cm/bottom + pivot 16.3 17.5 28.0 22.5 28.1 0.1 A9 7 101 + pivot 16.5** 16.5 15.5 10 15.9 0.4 A6 8 97 + pivot 17.6** 35.1 15.5 10 15.9 0.4 A13 9 75 + pivot 17.6 32 15.5 10 15.9 0.4 A7 10 98 + pivot 16.8** 36 12.7 7.2 13.6 0.9 A10 11 102 + pivot 16.5** 33 10.5 5 11.1 0.6 A8 12 99 + pivot 16.5** 35.7 10.5 5 11.1 0.6 A14 13 76 + pivot 17.3 17.5 10.5 5 10.9 0.4 A11 14 93 + pivot 16.7** 31.9 7.5 5.2 8.2 0.7 A5 15 100 + pivot 16.5** 35.3 7.5 5 8.1 0.6 A15 16 80 + pivot 17.0 17.5 7.5 22.5 8.4 0.9 A21 17 84 On tunnel lateral + door 9.5 A22 18 85 On tunnel lateral + door 4.5 A23 19 86 On tunnel lateral + door 2.5 A24 20 87 On tunnel lateral + door
A26 21 88 On tunnel top +top
A25 22 90 On tunnel top +top
A16 23 91 External box + door
A17 24 92 External box + door
A18 25 106 External box + door
A19 26 108 External box + door ** Measurement in X direction taken from the Teflon plate surface: 1 cm should be added to compare to others
SERIES 227887 TA Project: DRESBUS II
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Table 4.2 Extensometers numbering
A/A DAS Channel Column in data file Strain gauge F1 27 27 F3.1 F2 28 28 F3.2 F3 29 29 F3.3 F4 31 30 F3.4 F5 32 31 F3.5 F6 49 32 F3.6 F7 50 33 F3.7 F8 51 34 F3.8 F9 52 35 F3.9
F10 53 36 F3.10 D3 54 37 CL5 D4 55 38 CL6 D1 56 39 CL7 D2 57 40 CL8
The accelerometers were installed in vertical arrays (Fig. 4.2). Figs. 4.3-4.6 show filtered
acceleration time histories. Figs. 4.7-4.10 summarize the distribution of the maximum horizontal
accelerations with depth indicating soil amplification effects.
A2A3
A4
A20
A12
A9 A6 A13A7
A10A11
A8 A5
A14A15
Array 1
Array 2
Array 3
Array 4
Array 5
A16
A17
A18A19
A1
Fig. 4.2 Accelerometers vertical arrays
Fig. 4.11 presents representative transfer functions computed along the free field, the tunnel and
the reference array (ESB container) for EQ1. The results do not clearly show the predominant
frequencies of the soil-tunnel system.
SERIES 227887 TA Project: DRESBUS II
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Fig. 4.12 presents vertical acceleration time histories near the soil base and on the tunnel’s roof
slab sides during EQ2 (control points 25 and 26 in Fig. 4.1), indicating a yawing movement of
the ESB container. The in-phase response of the tunnel roof corners denotes a racking-type of
deformation. However, further investigation is needed to comment on a possible mobilization of
a “rocking-motion component”.
Typical stress-strain loops based on Zeghal and Elgamal procedure (Zeghal and Elgamal, 1994)
between sets of accelerometers are presented in Figs. 4.13-4.14. In Fig. 4.15 the shear wave
velocities, estimated according to the mobilized shear moduli, derived from the stress-strain
loops, are compared to the small strain shear wave velocity (Vso). The latter is estimated
according to the Hardin and Drenvich (1976) model. The results indicate reduction of the
velocities with increasing amplitude of the input motion. Moreover, Vs seem to be lower close to
the tunnel section compared to free-field values.
Figs. 4.16-4.17 present filtered deformation time histories recorded on the tunnels wall. In the
third column the recorded at each level signals are compared, inverting the polarity of one of the
compared signals. The results referring to EQ1 and EQ4, indicate an out of phase response for
the sensors located at the same level, while similar results are reported for the other shakes. As
expected the walls deformations are increased towards the roof slab. The maximum wall
deformations, as recorded for both the walls are compared for all the shakes in Fig. 4.18. The
walls deformations are increased with the increase of the amplitude input motion. Moreover, the
results indicated minor differences between the walls distributions, revealing an almost
symmetric response of the walls.
Figs. 4.19-4.20 present typical time histories of the tunnel diagonal deformations recorded by the
diagonal blades, indicating an in plane response of the tunnels.
Similar results were reported using the band pass filter for the tunnel deformation signals (Figs.
4.21 - 4.23). The maximum walls deformations were slightly smaller than the values observed by
the low pass filter results, due to the preclusion of the small residual values in this case.
SERIES 227887 TA Project: DRESBUS II
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CPT tests results obtained before and after the main test are summarized in Fig. 4.24. The results
indicate soil densification during shaking, as reflected in Fig. 4.25.
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A2
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A3
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A4
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A5
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A6
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A7
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A8
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A9
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A10
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A11
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A12
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A13
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A14
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A15
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A16
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A17
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A18
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A19
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A20
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A21
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A22
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A23
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A24
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A26
Fig. 4.3 Processed acceleration time histories – EQ1
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0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A2
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A3
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A4
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A5
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A6
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A7
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A8
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A9
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A10
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A11
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A12
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A13
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A14
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A15
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A16
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A17
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A18
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A19
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A20
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A21
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A22
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A23
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A24
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A26
Fig. 4.4 Processed acceleration time histories – EQ2
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A2
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A3
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A4
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A5
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A6
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A7
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A8
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A9
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A10
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A11
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A12
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A13
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A14
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A15
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A16
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A17
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A18
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A19
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A20
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A21
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A22
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A23
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A24
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A26
Fig. 4.5 Processed acceleration time histories – EQ3
SERIES 227887 TA Project: DRESBUS II
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0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A/4
0g
A1 − Input
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A2
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A3
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A4
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A5
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A6
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A/4
0g
A7
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A8
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A9
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A10
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A11
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A12
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A/4
0g
A13
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A14
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A15
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A16
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A17
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A18
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A/4
0g
A19
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A20
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A21
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A22
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A23
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A24
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A/4
0g
A25
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A26
Fig. 4.6 Processed acceleration time histories – EQ4
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0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.15 0.2 0.250.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.7 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.2 0.25 0.3 0.35 0.40.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.8 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2
SERIES 227887 TA Project: DRESBUS II
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0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.25 0.3 0.35 0.4 0.45 0.50.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.9 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.4 0.45 0.5 0.55 0.60.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.10 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4
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0 50 100 150 200 250 300 350 4000
5
10
15
20
f(Hz)
Am
plit
ud
e
Transfer functions
Reference arrayFree Field arrayTunnel array
Fig. 4.11 Typical transfer functions along vertical accelerometers arrays – EQ1
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
A/4
0g
A20
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
A25
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
A26
0.2 0.4 0.6−0.1
−0.05
0
0.05
0.1
t(s)
A/4
0g
A25 vs A26
Fig. 4.12 Vertical accelerations – EQ2
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−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20
stre
ss (
kPa)
A12−A13
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20A13−A14
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20A14−A15
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20
strain (%)
A6−A7
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20
strain (%)
stre
ss (
kPa)
A7−A8
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20
strain (%)
A9−A10
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20
strain (%)
A10−A11
Fig. 4.13 Stress-strain loops – EQ1
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60
stre
ss (
kPa)
A12−A13
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60A13−A14
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60A14−A15
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60
strain (%)
A6−A7
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60
strain (%)
stre
ss (
kPa)
A7−A8
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60
strain (%)
A9−A10
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60
strain (%)
A10−A11
Fig. 4.14 Stress-strain loops – EQ4
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0 100 200 3000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Dep
th(m
)Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ1
0 100 200 3000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ2
0 100 200 3000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ3
0 100 200 3000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ4
Fig. 4.15 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
D(m
m)
F1
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05F6
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05F1−F6
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
D(m
m)
F2
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05F7
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05F2−F7
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
D(m
m)
F3
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05F8
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05F3−F8
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
D(m
m)
F4
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05F9
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05F4−F9
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
D(m
m)
F5
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
F10
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05
t(s)
F5−F10
Fig. 4.16 Walls deformations obtained using a low pass filter – EQ1
SERIES 227887 TA Project: DRESBUS II
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0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F1
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F6
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F1−F6
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F2
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F7
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F2−F7
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F3
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F8
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F3−F8
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F4
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F9
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F4−F9
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
F5
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
F10
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15
t(s)
F5−F10
Fig. 4.17 Walls deformations obtained using a low pass filter – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ1
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.18 Walls maximum deformations obtained using a low pass filter
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D2
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D3
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D4
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.19 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
D1
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D2
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D3
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D4
0.2 0.25 0.3−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.20 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F1
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F6
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F1−F6
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F2
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F7
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F2−F7
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F3
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F8
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F3−F8
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F4
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F9
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F4−F9
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
F5
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
F10
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15
t(s)
F5−F10
Fig. 4.21 Walls deformations obtained using a band pass filter – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.22 Walls maximum deformations obtained using a band pass filter
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
D2
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
D3
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
D4
0.25 0.3 0.35−0.1
−0.05
0
0.05
0.1
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.23 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ3
0 100 200 3000
50
100
150
200
250
300
350
Dep
th(m
m)
Force (daN)
Before testAfter test
Fig. 4.24 CPT test results
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0 100 200 300 400 500 600 700 800 900 1000 11000
1
2
3
4
5
6
Sampling point
Set
tlem
ent(
mm
)
S1S2
Fig. 4.25 Soil surface settlements
Stabilization circles
Northridge 0.1g to 0.3g
Sine wavelet
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4.2 TEST DRESBUS_2_2_1
Fig 4.26 presents the model set up along with instrumentation scheme. Tables 4.3 and 4.4
summarize channels and sensors locations before and after the main test. The coordinates refer to
the reference system presented in Fig. 2.21. The settlements estimated for each instrument by the
direct measurements are also reported.
DRESBUS2_2_1: Flexible tunnel ‐ Smooth surface ‐ Dry Sand
250mm
400mm240mm
360mm
180mm326mm
360mm
A2
A1
A3
A4
A20
A12
A9 A6 A13A7
A10A11
A8 A5
130mm
130mm
A14A15
20mm
100mm
A23
A24
A21
A22
A25A26F5
F1F5
F10
D1 D2D3
D4
S1 S3
800mm
Dry Fontainebleau Sand(Dr=70%)
50mm
47mm
Model
14mm
y
x
z
S2
Accelerometer Laser displacementssensor
Diagonal extensiometer Transversal "fork"extensiometer
1.5mm6.0mm
A16
A17
A18A19
Fig. 4.26 Test DRESBUS_2_2_1 model set up and instrumentation scheme
SERIES 227887 TA Project: DRESBUS II
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Table 4.3 Sensors numbering and exact positions
Real coordinates at set-up
Real Position after shocksA/A
DAS Channel
Sensor #
Position Positive Direct X
cm Y
cm Z / top box
cm Z / surface
cm Z / top box
cm Settlement
cm A1 1 68 End table + pivot A2 2 69 Bottom plate + pivot A20 3 77 Bottom plate +top A3 4 95 Above plate + pivot 16.3** 39 39.2 34.2 39.2 0 A4 5 96 +13 cm/bottom + pivot 17.5** 40.3 27.8 22.8 28 0.2 A12 6 74 +13 cm/bottom + pivot 17.5 17.7 27.6 22.6 27.7 0.1 A9 7 100 + pivot 17.5 48.5** 14.5 9.5 14.9 0.4 A6 8 97 + pivot 17.5 44.5** 14.5 9.5 14.85 0.35 A13 9 75 + pivot 17.2 18 14.5 9.5 14.9 0.4 A7 10 98 + pivot 17.2 44.5** 12.2 7.2 12.35 0.15 A10 11 102 + pivot 17 47.7** 9.5 4.5 9.85 0.35 A8 12 99 + pivot 17 44.5** 9.5 4.5 9.85 0.35 A14 13 76 + pivot 17.3 17.3 9.5 4.5 10 0.5 A11 14 93 + pivot 17.8 48 6.8 1.8 6.9 0.1 A5 15 101 + pivot 17.5** 40 6.8 1.8 7.3 0.5 A15 16 80 + pivot 17.8 17.4 6.5 1.5 7.1 0.6 A23 17 84 On tunnel lateral + door A24 18 85 On tunnel lateral + door A22 19 86 On tunnel lateral + door A21 20 87 On tunnel lateral + door
A25 21 88 On tunnel top +top
A16 22 90 External box +door
A26 23 89 On tunnel top +top
A17 24 92 External box + door
A18 25 106 External box + door
A19 26 108 External box + door
** Measurement in X direction taken from the Teflon plate surface: 1 cm should be added to compare to others
SERIES 227887 TA Project: DRESBUS II
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Table 4.4 Extensometers numbering
A/A DAS Channel Column in data file Strain gauge F5 27 27 F3.1 F4 28 28 F3.2 F3 29 29 F3.3 F2 30 30 F3.4 F1 31 31 F3.5 F10 32 32 F3.6 F9 33 33 F3.7 F8 34 34 F3.8 F7 35 35 F3.9 F6 36 36 F3.10 D3 37 37 CL5 D4 38 38 CL6 D1 39 39 CL7 D2 40 40 CL8
Figs. 4.27-4.30 show filtered acceleration time histories, while in the Figs. 4.31-4.34 the
maximum horizontal accelerations, obtained along the vertical accelerometer arrays for all
shakes are summarized.
Similar to the first test case, the computed transfer functions did not clearly show the
predominant frequencies of the soil-tunnel system. Moreover, the yawing movement of the ESB
container on the shaking table and the in phase response of the vertical acceleration records on
the tunnel’s roof slab edges were also observed. Similar conclusions are also drawn regarding the
computed shear wave velocity profiles, estimated based to the Zeghal and Elgamal procedure
(Fig. 4.35). Finally, the tunnel deformed in a similar manner with the previous test (Figs. 4.36-
4.40).
CPT tests results obtained before and after the main test are summarized in Fig. 4.41. The results
indicate soil densification during shaking, as reflected in Fig. 4.42. The settlements above the
tunnel were slightly larger compared to the free field, during the stabilization circles, while the
opposite observed during shaking.
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A2
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A3
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A4
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A5
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A6
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A7
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A8
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A9
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A10
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A11
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A12
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A13
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A14
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A15
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A16
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A17
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A18
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A19
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A20
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A21
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A22
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A23
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A24
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A26
Fig. 4.27 Processed acceleration time histories – EQ1
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0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A2
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A3
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A4
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A5
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A6
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A7
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A8
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A9
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A10
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A11
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A12
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A13
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A14
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A15
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A16
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A17
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A18
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A19
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A20
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A21
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A22
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A23
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A24
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A26
Fig. 4.28 Processed acceleration time histories – EQ2
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A2
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A3
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A4
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A5
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A6
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A7
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A8
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A9
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A10
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A11
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A12
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A13
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A14
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A15
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A16
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A17
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A18
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A19
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A20
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A21
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A22
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A23
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A24
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A26
Fig. 4.29 Processed acceleration time histories – EQ3
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0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A1 − Input
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A2
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A3
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A4
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A5
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A6
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A7
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A8
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A9
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A10
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A11
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A12
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A13
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A14
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A15
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A16
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A17
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A18
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A19
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A20
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A21
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A22
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A23
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A24
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A/4
0g
A25
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A26
Fig. 4.30 Processed acceleration time histories – EQ4
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0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.05 0.1 0.15 0.2 0.30.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.31 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.15 0.2 0.25 0.3 0.35 0.40.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.32 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2
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0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.25 0.3 0.35 0.4 0.45 0.50.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.33 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. – EQ3
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.3 0.4 0.5 0.6 0.7 0.80.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.34 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4
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0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ1
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ2
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ3
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ4
Fig. 4.35 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
D(m
m)
F1
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08F6
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08F1−F6
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
D(m
m)
F2
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08F7
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08F2−F7
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
D(m
m)
F3
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08F8
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08F3−F8
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
D(m
m)
F4
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08F9
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08F4−F9
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
t(s)
D(m
m)
F5
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
t(s)
F10
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08
t(s)
F5−F10
Fig. 4.36 Walls deformations obtained using a low pass filter – EQ2
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0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ4
Fig. 4.37 Walls maximum deformations obtained using a low pass filter
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0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D2
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D3
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D4
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.38 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ3
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
D1
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D2
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D3
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D4
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.39 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ4
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0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ4
Fig. 4.40 Walls maximum deformations obtained using a band pass filter
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0 100 200 3000
50
100
150
200
250
300
350
Dep
th(m
m)
Force (daN)
Before test
Fig. 4.41 CPT test results
0 100 200 300 400 500 600 700 800 9000
1
2
3
4
5
6
7
8
Sampling point
Set
tlem
ent(
mm
)
S1S2S3
Fig. 4.42 Soil surface settlements
Stabilization circles
Northridge 0.1g to 0.3g
Sine wavelet
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4.3 TEST DRESBUS_2_3_1
Fig 4.43 presents the model set up along with instrumentation scheme, while Tables 4.5 and 4.6
summarize channels and sensors locations before and after the main test.
DRESBUS2_3_1: Rigid tunnel ‐Rough surface ‐ Dry Sand
250mm
400mm240mm
360mm
180mm326mm
360mm
A2
A1
A3
A4
A20
A12
A9 A6 A13A7
A10A11
A8 A5
130mm
130mm
A14A15
20mm
100mm
F5
F1F6
F10
D1 D2D3
D4
S1 S3
800mm
Dry Fontainebleau Sand(Dr=70%)
Model
14mm
y
x
z
S2
Accelerometer Laser displacement sensor
Diagonal extensiometer Transversal "fork"extensiometer
50mm
5.0mm6.0mm54mm
A23
A24
A21
A22
A25A26
A16
A17
A18A19
Fig. 4.43 Test DRESBUS_2_3_1 model set up and instrumentation scheme
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Table 4.5 Sensors numbering and exact positions
Real coordinates at set-up
Real Position after shocksA/A
DAS Channel
Sensor #
Position Positive Direct X
cm Y
cm Z / top box
cm Z / surface
cm Z / top box
cm Settlement
cm A1 1 68 End table + pivot A2 2 69 Bottom plate + pivot A20 3 79 Bottom plate +top A3 4 95 Above plate + pivot 17.5 40 39.5 34.4 39.7 A4 5 96 +13 cm/bottom + pivot 17 39.5 27.5 22.4 27.7 A12 6 74 +13 cm/bottom + pivot 17 24.5 27.5 22.4 27.7 A9 7 101 + pivot 17 32.3 15 9.9 15 A6 8 91 + pivot 17 35.2 15 9.9 15.1 A13 9 75 + pivot 17.3 24.2 15 9.9 15.2 A7 10 99 + pivot 17.5 35.5 12.5 7.4 12.5 A10 11 102 + pivot 17.1 32.3 10 4.9 10.3 A8 12 93 + pivot 17.2 35 10 4.9 10.2 A14 13 76 + pivot 17.5 24.1 10 4.9 10.55 A11 14 97 + pivot 17.5 32 7.8** 7.8 A5 15 100 + pivot 17 40 7.8** 7.8 A15 16 80 + pivot 17.5 24.1 7.8** 7.8 A23 17 84 On tunnel lateral + door A24 18 85 On tunnel lateral + door A22 19 86 On tunnel lateral + door A21 20 87 On tunnel lateral + door
A25 21 88 On tunnel top +top
A26 22 89 On tunnel top +top
A16 23 90 External box + door
A17 24 92 External box + door
A18 25 106 External box + door
A19 26 108 External box + door
** Erroneous measurements Figs. 4.44-4.47 show filtered acceleration time histories obtained for this test, while in the Figs.
4.48-4.51 the maximum horizontal accelerations, obtained along the vertical accelerometer
arrays for all shakes are summarized. The horizontal acceleration was slightly amplified towards
the soil surface. The acceleration recorded at the invert slab was found to be larger than the
acceleration on the roof. It is noted that the maximum acceleration is estimated as the absolute
maximum value of the time history. To this end, the values may biased by signal spikes that are
not eliminated by the filter. Further study, using also the numerical simulation results is needed
to better understand this behavior.
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Table 4.6 Extensometers numbering
A/A DAS
Channel Column in data file Strain gauge
D1 27 37 CL5 D2 28 38 CL6 D4 29 39 CL7 D3 30 40 CL8 F10 31 27 F3.1 F9 32 28 F3.2 F8 33 29 F3.3 F7 34 30 F3.4 F6 35 31 F3.5 F5 36 32 F3.6 F4 37 33 F3.7 F3 38 34 F3.8 F2 39 35 F3.9 F1 40 36 F3.10
Similar observations with the previous tests are made regarding the transfer functions, the
vertical acceleration and the Vs profiles. Although the rigid tunnel deformed less than the flexible
tunnels, similar observations were made for the tunnel deformations, namely: increase of the
walls deformations reaching the roof slab, increase of the tunnel deformations with the increase
of the input motion amplitude and in phase response of the diagonal deformations (Figs. 4.53-
4.58).
CPT tests results obtained before and after the main test are summarized in Fig. 4.59. The results
indicate soil densification during shaking, as reflected in Fig. 4.60.
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0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A2
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A3
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A4
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A5
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A6
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A7
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A8
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A9
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A10
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A11
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A12
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A13
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A14
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A15
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A16
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A17
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A18
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A19
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A20
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A21
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A22
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A23
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A24
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A26
Fig. 4.44 Processed acceleration time histories – EQ1
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0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A2
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A3
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A4
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A5
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A6
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A7
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A8
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A9
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A10
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A11
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A12
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A13
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A14
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A15
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A16
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A17
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A18
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A19
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A20
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A21
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A22
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A23
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A24
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A26
Fig. 4.45 Processed acceleration time histories – EQ2
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0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A2
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A3
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A4
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A5
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A6
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A7
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A8
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A9
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A10
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A11
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A12
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A13
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A14
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A15
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A16
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A17
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A18
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A19
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A20
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A21
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A22
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A23
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A24
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A26
Fig. 4.46 Processed acceleration time histories – EQ3
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0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A1 − Input
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A2
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A3
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A4
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A5
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A6
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A7
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A8
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A9
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A10
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A11
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A12
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A13
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A14
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A15
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A16
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A17
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A18
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A19
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A20
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A21
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A22
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A23
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A24
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A/4
0g
A25
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A26
Fig. 4.47 Processed acceleration time histories – EQ4
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0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.3 0.40.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.48 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.15 0.25 0.35 0.450.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.49 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2
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0 0.125 0.25 0.375 0.50
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.125 0.25 0.375 0.50
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.125 0.25 0.375 0.5
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.125 0.25 0.375 0.5
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.125 0.25 0.375 0.50
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.25 0.35 0.45 0.550.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.50 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.35 0.45 0.55 0.650.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.51 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4
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0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ1
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ2
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ3
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ4
Fig. 4.52 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation
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0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F1
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F6
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F1−F6
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F2
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F7
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F2−F7
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F3
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F8
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F3−F8
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F4
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F9
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F4−F9
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D(m
m)
F5
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
F10
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01
t(s)
F5−F10
Fig. 4.53 Walls deformations obtained using a low pass filter – EQ1
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0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
D(m
m)
F1
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03F6
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03F1−F6
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
D(m
m)
F2
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03F7
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03F2−F7
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
D(m
m)
F3
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03F8
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03F3−F8
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
D(m
m)
F4
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03F9
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03F4−F9
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
t(s)
D(m
m)
F5
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
t(s)
F10
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03
t(s)
F5−F10
Fig. 4.54 Walls deformations obtained using a low pass filter – EQ4
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0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ1
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.55 Walls maximum deformations obtained using a low pass filter
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0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
D2
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
D3
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
D4
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.56 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ2
0 0.16 0.32 0.48 0.64−0.08
−0.04
0
0.04
0.08
t(s)
D(m
m)
D1
0 0.16 0.32 0.48 0.64−0.08
−0.04
0
0.04
0.08
t(s)
D2
0 0.16 0.32 0.48 0.64−0.08
−0.04
0
0.04
0.08
t(s)
D3
0 0.16 0.32 0.48 0.64−0.08
−0.04
0
0.04
0.08
t(s)
D4
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.57 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ4
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0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.58 Walls maximum deformations obtained using a band pass filter
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0 100 200 3000
50
100
150
200
250
300
350
Dep
th(m
m)
Force (daN)
Before test
Fig. 4.59 CPT test results
0 200 400 600 800 1000 12000
1
2
3
4
5
6
7
8
Sampling point
Set
tlem
ent(
mm
)
S1S2S3
Fig. 4.60 Soil surface settlements
4.4 TEST DRESBUS_2_4_1
This test was the first in saturated sand. The tunnel ends were formed following the configuration
presented in Fig 2.12b. This configuration did not manage to withstand the water pressures
during the tests, leading to water leakage inside the tunnel and subsequently to problems to the
extensometers that did not work properly.
Stabilization circles
Northridge 0.1g to 0.3g
Sine wavelet
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4.5 TEST DRESBUS_2_4_2
This test was a repetition of the test DRESBUS_2_4_1. Fig 4.61 presents the model set up along
with instrumentation scheme. The viscosity of the saturation fluid was formulated for a
temperature of 14°C which was verified to be consistent with the temperature in the centrifuge
room. The resulting viscosity was controlled just before the test to be between 39 and 40 cSt.
DRESBUS2_4_2: Rigid tunnel ‐ Rough surface ‐ Saturated Sand
250mm
400mm240mm
360mm
180mm326mm
360mm
A2
A1
A3
A4
A20
A12
A9 A6 A13A7
A10A11
A8 A5
130mm
130mm
A14A15
20mm
100mm
F5
F1F6
F10
D1 D2D3
D4
S1 S3
800mm
Dry Fontainebleau Sand(Dr=70%)
Model
14mm
y
x
z
S2
Accelerometer Displacementsensor
Diagonal extensiometer
Transversal "fork"extensiometers
50mm
5.0mm6.0mm54mm
A23
A24
A21
A22
A25A26
A16
A17
A18A19
Pore pressuresensors
A27
P3P1
P2 P4 P5
P6
Fig. 4.61 Test DRESBUS_2_4_2 model set up and instrumentation scheme
Tables 4.7 and 4.8 summarize channels and sensors locations before and after the main test. The
coordinates refer to the reference system presented in Fig. 2.21. The settlements estimated for
each instrument by the direct measurements are also reported.
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Table 4.7 Sensors numbering and exact positions
Real coordinates at set-up
Real Position after shocksA/A
DAS Channel
Sensor #
Positive Direct X
cm Y
cm Z / top box
cm Z / surface
cm Z / top box
cm Settlement
mm A1 1 68 + pivot A2 2 109 + pivot 17 41 46.6 36 A20 3 111 + top 17 34 46.6 36 A3 4 106 + pivot 16** 39 44.8 34.2 40.8 0 A27 5 97 +top 14.5 39 33.6 22.7 29.5 2 A4 6 99 + pivot 15.5 42 33.3 22.7 29.5 2 A12 7 98 + pivot 16 18 33.4 22.82 30 6 A9 8 101 + pivot 16 49 24 13.4 17.4 26*** A6 9 95 + pivot 15.8** 44.5 24.5 13.9 17.0 35*** A13 10 103 + pivot 16.6 19 27 16.4 18.2 48*** A7 11 96 + pivot 14.2** 55.5 18 7.4 14.6 6 A14 12 92 + pivot 17.7 18.4 15.1 4.5 13.1 20 A8 13 108 + pivot 15.6** 45.1 15.4 4.9 12.3 9 A10 14 102 + pivot 17 50 15.4 4.9 12.9 15 A15 15 104 + pivot 17 19 12.9 2.3 10.7 6 A5 16 105 + pivot 16** 38 13 2.4 9.6 6 A11 17 100 + pivot 17 46 13 2.4 10.4 14 A16 18 85 + door A17 19 86 + door A18 20 87 + door A19 21 88 + door A25 22 125 + top A26 23 126 + top A21 24 127 + door A22 25 128 + door A24 26 129 + door A23 27 130 + door P1 28 5798 15** 39 -21.5 -10.9 -17.7 2 P3 29 5796 17 56 -21 -10.4 -17.5 5 P5 30 5799 13.4** 36 -18.4 -7.8 -15.0 6
P2 31 5805 17 59 -14.9 -4.3 Non
Measured
P4 32 5801 18.5 41.5 -13 -2.4 -10.6 16
P6 33 5803 Non
Measured
** Measurement in X direction taken from the Teflon plate surface: 1 cm should be added to compare to others *** Erroneous measurements
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Table 4.8 Extensometers numbering
A/A DAS
Channel Strain gauge
F6 34 F2.1 F7 35 F2.2 F8 36 F2.3 F9 37 F2.4 F10 38 F2.5 F5 39 F2.6 F4 40 F2.7 F3 41 F2.8 F2 42 F2.9 F1 43 F2.10 D4 44 CL9 D3 45 CL10 D2 46 CL11 D1 47 CL12
Due to a problem with the acquisition system, the tunnel deformations were not recorded during
shaking. Upon repairing of the problem the shaking program renewed. To this end, the shakes
were re-fired in an already modified soil-tunnel system.
Figs. 4.62-4.65 present the obtained filtered acceleration time histories for this test, while in the
Figs. 4.66-4.69 the maximum horizontal accelerations, obtained along the vertical accelerometer
arrays for all shakes, are summarized. Some of the acceleration time histories were highly
"decreased" during shaking. This observation explains the de-amplification of the maximum
horizontal acceleration from the soil base to the soil surface, as presented along the vertical
accelerometers arrays. This response is also observed to the tunnel distortion time histories.
Further investigation of the data in needed to conclude on whether this response is attributed to
recording issues or liquefaction of the sand deposit.
To capture the water pore pressures during and after shaking, pore pressure cells were used
(Figs. 4.76-4.79). The specific sensors were used for first time by the facility. Although the
sensors seemed to worked properly, a problem with their calibration exists. Table 4.9
summarizes the calibration procedure for the pore pressure cell P1 (left side), while the expected
initial pore pressure at the specific location is also presented for comparison (right side). The
differences are significant even if the settlement of the sensor is accounted. To this end the pore
SERIES 227887 TA Project: DRESBUS II
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pressure signals may have a consistent shape but their actual values are not reasonably
exploitable. Further investigation regarding this aspect is needed.
Table 4.9 Measured vs. theoretical water pore pressure at P1
Computation of the initial (static) pore pressures at the beginning of the test
Calculation of the hydrostatic Pore Pressure
Calibration coefficients Model sensor depth -10.9 cm Slope -4.3507 kPa/mV Water table (over sand
surface) 1.5 cm
Offset 191.11 kPa Prototype depth 4.36 m Measurement 14.66 mV Prototype Water table 0.60 m Computed absolute pore pressure
127.33 kPa Total water height 4.96 m
Atmospheric pressure 101.20 kPa Water density 1000 kg/m3 Computed relative pore pressure
26.13 kPa Static Theoretical Pore Pressure
48.7 kPa
Generally, the pore pressures were increased during shaking. After shaking pore pressures
recorded at P1, P3 and P5 continue to increase, while at P2 and P4 the pore pressures tend to
decrease indicating a possible flow from higher levels to the tunnel foundation level.
Fig. 4.80 presents the results of the CPT test performed prior the main test. The curve appears to
be concave rather than convex toward the top and not completely monotonous, meaning
probably a default of regularity in the pluvation. However, this default is of reduced amplitude.
SERIES 227887 TA Project: DRESBUS II
85
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A2
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A3
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A4
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A5
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A6
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A7
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A8
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A9
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A10
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A11
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A12
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A13
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A14
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A15
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A16
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A17
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A18
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A19
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A20
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A21
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A22
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A23
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A24
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A26
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A27
Fig. 4.62 Processed acceleration time histories – EQ1
SERIES 227887 TA Project: DRESBUS II
86
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A2
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A3
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A4
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A5
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A6
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A7
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A8
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A9
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A10
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A11
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A12
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A13
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A14
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A15
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A16
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A17
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A18
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A19
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A20
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A21
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A22
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A23
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A24
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A26
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A27
Fig. 4.63 Processed acceleration time histories – EQ2
SERIES 227887 TA Project: DRESBUS II
87
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A2
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A3
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A4
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A5
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A6
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A7
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A8
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A9
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A10
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A11
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A12
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A13
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A14
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A15
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A16
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A17
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A18
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A19
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A20
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A21
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A22
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A23
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A24
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A26
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A27
Fig. 4.64 Processed acceleration time histories – EQ3
SERIES 227887 TA Project: DRESBUS II
88
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A2
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A3
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A4
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A5
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A6
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A/4
0g
A7
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A8
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A9
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A10
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A11
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A12
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A/4
0g
A13
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A14
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A15
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A16
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A17
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A18
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A/4
0g
A19
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
A20
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
t(s)
A21
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
t(s)
A22
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
t(s)
A23
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
t(s)
A24
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
t(s)
A26
0 0.16 0.32 0.48 0.64−0.4−0.2
00.20.4
t(s)
A27
Fig. 4.65 Processed acceleration time histories – EQ4
SERIES 227887 TA Project: DRESBUS II
89
0 0.05 0.1 0.15 0.20
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.05 0.1 0.15 0.20
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.05 0.1 0.15 0.2
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.05 0.1 0.15 0.2
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.05 0.1 0.15 0.20
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.05 0.1 0.15 0.20.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.66 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1
0 0.075 0.15 0.225 0.30
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.075 0.15 0.225 0.30
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.3 0.40.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.67 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2
SERIES 227887 TA Project: DRESBUS II
90
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.3 0.4 0.50.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.68 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.3 0.4 0.50.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.69 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4
SERIES 227887 TA Project: DRESBUS II
91
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F1
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F6
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F1−F6
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F2
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F7
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F2−F7
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F3
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F8
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F3−F8
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F4
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F9
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F4−F9
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D(m
m)
F5
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
F10
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01
t(s)
F5−F10
Fig. 4.70 Walls deformations obtained using a low pass filter – EQ2
SERIES 227887 TA Project: DRESBUS II
92
0 0.16 0.32 0.48 0.64−0.01
−0.005
0
0.005
0.01
D(m
m)
F1
0 0.16 0.32 0.48 0.64−0.01
−0.005
0
0.005
0.01F6
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F1−F6
0 0.16 0.32 0.48 0.64−0.01
−0.005
0
0.005
0.01
D(m
m)
F2
0 0.16 0.32 0.48 0.64−0.01
−0.005
0
0.005
0.01F7
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F2−F7
0 0.16 0.32 0.48 0.64−0.01
−0.005
0
0.005
0.01
D(m
m)
F3
0 0.16 0.32 0.48 0.64−0.01
−0.005
0
0.005
0.01F8
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F3−F8
0 0.16 0.32 0.48 0.64−0.01
−0.005
0
0.005
0.01
D(m
m)
F4
0 0.16 0.32 0.48 0.64−0.01
−0.005
0
0.005
0.01F9
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F4−F9
0 0.16 0.32 0.48 0.64−0.01
−0.005
0
0.005
0.01
t(s)
D(m
m)
F5
0 0.16 0.32 0.48 0.64−0.01
−0.005
0
0.005
0.01
t(s)
F10
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01
t(s)
F5−F10
Fig. 4.71 Walls deformations obtained using a low pass filter – EQ4
SERIES 227887 TA Project: DRESBUS II
93
0 0.005 0.010
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ1
0 0.005 0.010
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.005 0.010
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.005 0.010
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.72 Walls maximum deformations obtained using a low pass filter
SERIES 227887 TA Project: DRESBUS II
94
0 0.25 0.5 0.75 1−1
−0.5
0
0.5
1x 10
−5
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−1
−0.5
0
0.5
1x 10
−5
t(s)
D2
0 0.25 0.5 0.75 1−1
−0.5
0
0.5
1x 10
−5
t(s)
D3
0 0.25 0.5 0.75 1−1
−0.5
0
0.5
1x 10
−5
t(s)
D4
0.25 0.3 0.35−1
−0.5
0
0.5
1x 10
−5
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.73 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1
0 0.25 0.5 0.75 1−1
−0.5
0
0.5
1x 10
−5
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−1
−0.5
0
0.5
1x 10
−5
t(s)
D2
0 0.25 0.5 0.75 1−1
−0.5
0
0.5
1x 10
−5
t(s)
D3
0 0.25 0.5 0.75 1−1
−0.5
0
0.5
1x 10
−5
t(s)
D4
0.25 0.3 0.35−1
−0.5
0
0.5
1x 10
−5
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.74 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ1
SERIES 227887 TA Project: DRESBUS II
95
0 0.005 0.010
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.005 0.010
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.005 0.010
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.005 0.010
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.75 Walls maximum deformations recorded by fork extensometers; low pass filter
SERIES 227887 TA Project: DRESBUS II
96
0 0.75 1.5 2.25 3127.3
127.4
127.5
127.6
t(s)
Po
re p
ress
ure
s(kP
a)P1
0 0.75 1.5 2.25 3113.5
114
114.5
115
t(s)
P2
0 0.75 1.5 2.25 3129.4
129.6
129.8
130
t(s)
P3
0 0.75 1.5 2.25 3253.3
253.35
253.4
253.45
253.5
t(s)
P4
0 0.75 1.5 2.25 3103.3
103.4
103.5
103.6
t(s)
Po
re p
ress
ure
s(kP
a)
P5
0 0.75 1.5 2.25 3112.9
113
113.1
113.2
t(s)
P6
Fig. 4.76 Water pore pressures during and after shaking – EQ1
0 0.75 1.5 2.25 3127.8
128
128.2
128.4
t(s)
Po
re p
ress
ure
s(kP
a)
P1
0 0.75 1.5 2.25 3113.5
114
114.5
115
t(s)
P2
0 0.75 1.5 2.25 3130
130.2
130.4
130.6
t(s)
P3
0 0.75 1.5 2.25 3253.1
253.2
253.3
253.4
253.5
t(s)
P4
0 0.75 1.5 2.25 3103.6
103.8
104
104.2
t(s)
Po
re p
ress
ure
s(kP
a)
P5
0 0.75 1.5 2.25 3113
113.1
113.2
113.3
t(s)
P6
Fig. 4.77 Water pore pressures during and after shaking – EQ2
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0 0.75 1.5 2.25 3128.8
128.9
129
129.1
129.2
t(s)
Po
re p
ress
ure
s(kP
a)P1
0 0.75 1.5 2.25 3114
114.5
115
115.5
116
t(s)
P2
0 0.75 1.5 2.25 3130.8
131
131.2
131.4
t(s)
P3
0 0.75 1.5 2.25 3252.9
252.95
253
253.05
253.1
t(s)
P4
0 0.75 1.5 2.25 3104.3
104.4
104.5
104.6
t(s)
Po
re p
ress
ure
s(kP
a)
P5
0 0.75 1.5 2.25 3113.2
113.3
113.4
113.5
t(s)
P6
Fig. 4.78 Water pore pressures during and after shaking – EQ3
0 0.75 1.5 2.25 3129.7
129.8
129.9
130
130.1
t(s)
Po
re p
ress
ure
s(kP
a)
P1
0 0.75 1.5 2.25 3114.5
115
115.5
116
116.5
t(s)
P2
0 0.75 1.5 2.25 3131.4
131.6
131.8
132
t(s)
P3
0 0.75 1.5 2.25 3252.7
252.75
252.8
252.85
252.9
t(s)
P4
0 0.75 1.5 2.25 3104.9
105
105.1
105.2
t(s)
Po
re p
ress
ure
s(kP
a)
P5
0 0.75 1.5 2.25 3113.4
113.5
113.6
113.7
t(s)
P6
Fig. 4.79 Water pore pressures during and after shaking – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 100 200 3000
50
100
150
200
250
300
350
Dep
th(m
m)
Force (daN)
Before test
Fig. 4.80 CPT test results
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4.6 TEST DRESBUS_2_5_1
Fig 4.81 presents the model set up along with instrumentation scheme. Tables 4.10 and 4.11
summarize channels and sensors locations before and after the main test.
DRESBUS2_5_1: Rigid tunnel ‐ Smooth surface ‐ Dry Sand
250mm
400mm240mm
360mm
180mm326mm
360mm
A2
A1
A3
A4
A20
A12
A9 A6 A13A7
A10A11
A8 A5
130mm
130mm
A14A15
20mm
100mm
F5
F1F6
F10
D1 D2D3
D4
S1 S3
800mm
Dry Fontainebleau Sand(Dr=70%)
Model
19mm
y
x
z
S2
Accelerometer Laser displacementssensors
Diagonal extensiometers Transversal "fork"extensiometers
50mm
5.0mm6.0mm54mm
A23
A24
A21
A22
A25A26
A16
A17
A18A19
Fig. 4.81 Test DRESBUS_2_5_1 model set up and instrumentation scheme
SERIES 227887 TA Project: DRESBUS II
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Table 4.10 Sensors numbering and exact positions
Real coordinates at set-up
Real Position after shocksA/A
DAS Channel
Sensor #
Position Positive Direct X
cm Y
cm Z / top box
cm Z / surface
cm Z / top box
cm Settlement
cm A1 1 68 + pivot A2 2 69 + pivot 16* 40 41.2 41.2 0 A20 3 79 +top 16* 41 41.2 41.2 0 A3 4 97 + pivot 16.5* 40 39.3 39.2 0.1 A4 5 98 + pivot 16.5* 39.7 27.7 27.8 0.1 A12 6 99 + pivot 17 19 27.8 27.8 0.1 A13 7 91 + pivot 17.5 16.5 14.9 15.1 0.2
8 No sensor – clear
channel + pivot
A14 9 100 + pivot 18.5 15 9.5 9.9 0.4 A6 10 80 + pivot 16* 43.7 15 15.4 0.4 A9 11 82 + pivot 16* 46.5 15.3 15.6 0.3 A7 12 93 + pivot 16.5* 44 11.8 12.1 0.3 A10 13 76 + pivot 16.5* 47.4 9.85 10.1 0.2 A8 14 101 + pivot 16* 44.2 9.6 9.8 0.2 A15 15 75 + pivot 17 17.5 6.7 7.1 0.3 A5 16 74 + pivot 16.5* 39.8 6.8 7.1 0.3 A16 17 84 + door A17 18 85 + door A18 19 86 + door A19 20 87 + door
A24 21 102 + door
A21 22 103 + door
A23 23 104 + door
A22 24 105 + door
A25 25 106 +top
A26 26 108 +top
* Measurement in X direction taken from the Teflon plate surface: 1 cm should be added to compare to others
SERIES 227887 TA Project: DRESBUS II
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Table 4.11 Extensometers numbering
A/A DAS
Channel Strain gauge
F5 27 F2.1 F4 28 F2.2 F3 29 F2.3 F2 30 F2.4 F1 31 F2.5 F6 32 F2.6 F7 33 F2.7 F8 34 F2.8 F9 35 F2.9 F10 36 F2.10 D1 37 CL9 D2 38 CL10 D3 39 CL11 D4 40 CL12
Figs. 4.82-4.85 summarize filtered acceleration time histories obtained for this test, while in the
Figs. 4.86-4.89 the maximum horizontal accelerations are summarized. The horizontal
acceleration was generally amplified towards the soil surface.
The recorded tunnel deformations (Figs. 4.90- 4.93) indicated unrealistically large deformations
for the tunnel (deformations larger than for the flexible tunnels), probably due to a recoding
problem.
CPT test results, obtained before the main test, are summarized in Fig. 4.94, while Fig. 4.95
summarizes the recorded soil surface settlements.
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0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A2
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A3
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A4
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A5
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A6
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A7
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A8
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A9
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A10
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A11
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A12
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A13
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A14
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A15
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A16
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A17
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A18
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A19
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A20
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A21
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A22
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A23
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A24
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A26
Fig. 4.82 Processed acceleration time histories – EQ1
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0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A2
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A3
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A4
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A5
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A6
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A7
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A8
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A9
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A10
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A11
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A12
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A13
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A14
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A15
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A16
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A17
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A18
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A19
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A20
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A21
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A22
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A23
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A24
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A26
Fig. 4.83 Processed acceleration time histories – EQ2
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0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A2
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A3
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A4
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A5
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A6
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A/4
0g
A7
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A8
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A9
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A10
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A11
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A12
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A/4
0g
A13
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A14
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A15
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A16
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A17
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A18
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A/4
0g
A19
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
A20
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
t(s)
A21
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
t(s)
A22
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
t(s)
A23
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
t(s)
A24
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.6−0.3
00.30.6
t(s)
A26
Fig. 4.84 Processed acceleration time histories – EQ3
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0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A1 − Input
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A2
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A3
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A4
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A5
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A6
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A7
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A8
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A9
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A10
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A11
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A12
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A13
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A14
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A15
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A16
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A17
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A18
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A19
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A20
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A21
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A22
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A23
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A24
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A/4
0g
A25
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A26
Fig. 4.85 Processed acceleration time histories – EQ4
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0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.30.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.86 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.15 0.25 0.35 0.450.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.87 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2
SERIES 227887 TA Project: DRESBUS II
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0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.25 0.35 0.45 0.550.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.88 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.35 0.45 0.55 0.650.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.89 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2
D(m
m)
F1
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2F6
0.25 0.3 0.35−0.2
−0.1
0
0.1
0.2F1−F6
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2
D(m
m)
F2
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2F7
0.25 0.3 0.35−0.2
−0.1
0
0.1
0.2F2−F7
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2
D(m
m)
F3
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2F8
0.25 0.3 0.35−0.2
−0.1
0
0.1
0.2F3−F8
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2
D(m
m)
F4
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2F9
0.25 0.3 0.35−0.2
−0.1
0
0.1
0.2F4−F9
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2
t(s)
D(m
m)
F5
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2
t(s)
F10
0.25 0.3 0.35−0.2
−0.1
0
0.1
0.2
t(s)
F5−F10
Fig. 4.90 Walls deformations obtained using a low pass filter – EQ1
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2
t(s)
D2
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2
t(s)
D3
0 0.25 0.5 0.75 1−0.2
−0.1
0
0.1
0.2
t(s)
D4
0.25 0.3 0.35−0.2
−0.1
0
0.1
0.2
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.91 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1
SERIES 227887 TA Project: DRESBUS II
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0 0.3 0.60
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ1
0 0.3 0.60
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.3 0.60
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.4 0.80
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.92 Walls maximum deformations obtained using a low pass filter
SERIES 227887 TA Project: DRESBUS II
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0 0.3 0.60
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.3 0.60
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.3 0.60
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.4 0.80
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.93 Walls maximum deformations obtained using a band pass filter
SERIES 227887 TA Project: DRESBUS II
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0 100 200 3000
50
100
150
200
250
300
350
Dep
th(m
m)
Force (daN)
Before test
Fig. 4.94 CPT test results
0 100 200 300 400 500 600 7000
1
2
3
4
5
6
Sampling point
Set
tlem
ent(
mm
)
S1S2S3
Fig. 4.95 Soil surface settlements
Stabilization circles Northridge
0.1g to 0.3g
Sine wavelet
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4.7 TEST DRESBUS_2_6_1
Fig 4.96 presents the model setup along with instrumentation scheme. Tables 4.12 and 4.13
summarize channels and sensors locations before and after the main test.
DRESBUS2_6_1: Rigid tunnel ‐ Smooth surface ‐ Saturated Sand
250mm
400mm240mm
360mm
180mm326mm
360mm
A2
A1
A3
A4
A20
A12
A9 A6 A13A7
A10 A8 A5
130mm
130mm
A14A15
20mm
100mm
F5
F1F6
F10
D1 D2D3
D4
S1 S3
800mm
Dry Fontainebleau Sand(Dr=70%)
Model
14mm
y
x
z
S2
Accelerometer Laser displacementssensor
Diagonal extensiometer
Transversal "fork"extensiometers
50mm
5.0mm6.0mm54mm
A23
A24
A21
A22
A25A26
A16
A17
A18A19
Pore pressuresensors
A27
P1
P2 P4 P3
A28 A29
Fig. 4.96 Test DRESBUS_2_6_1 model set up and instrumentation scheme
The viscosity of the saturation fluid was formulated for a temperature of 18°C which was
verified to be consistent with the temperature in the centrifuge room. The resulted viscosity was
checked one day before the test to be around 32 cSt.
SERIES 227887 TA Project: DRESBUS II
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Table 4.13 Sensors numbering and exact positions
Real coordinates at set-up
Real Position after shocksA/A
DAS Channel
Sensor #
Positive Direct X
cm Y
cm Z / top box
cm Z / surface
cm Z / top box
cm Settlement
mm A1 1 68 + pivot A2 2 90 + pivot 16 39 46.2 36 A20 3 108 + top 16 41 46.2 36 A3 4 91 + pivot 16.5 40.5 44.7 34.5 40.8 3.9 A4 5 101 + pivot 16 39.5 32.7 22.5 29.1 3.6 A27 6 96 +top 16* 42.5 32.6 22.4 29.1 3.5 A12 7 104 + pivot 16.5 19 32.7 22.5 29.1 3.6 A6 8 103 + pivot 14.5* 43.5 20.4 10.2 16.5 3.9 A9 9 106 + pivot 14* 47 20.1 9.9 16.4 3.7 A13 10 105 + pivot 16 18 20.3 10.1 17.2 3.1 A7 11 95 + pivot 16* 44.5 17.4 7.2 A10 12 100 + pivot 16.2 48 15.1 4.9 11.6 3.5 A8 13 99 + pivot 15.6* 44.3 15.3 5.1 11.5 3.8 A14 14 98 + pivot 17.7 18.3 14.6 4.4 11.6 3 A5 15 97 + pivot 14.5* 43.5 12.2 2 8.6 3.6 A15 16 102 + pivot 15.7 21.4 11.5 1.3 8.6 2.9 A28 17 124 + top 15.7* 40.2 11.9 1.7 A29 18 92 + top 15.5 18.5 11.3 1.1 8.05 3.25 A26 19 125 + top A25 20 126 + top A21 21 127 + door A22 22 128 + door A24 23 129 + door A23 24 130 + door A16 25 83 + door A17 26 84 + door A18 27 85 + door A17 86 + door P1 28 5802 18.5 59 20.5 10.3 17.2 3.3 P3 29 5805 17* 35 17.4 7.2 14.4 3 P2 30 5804 17.8 55.2 14.4 4.2 11.3 3.1 P4 31 5796 16.5 40 14.5 4.3
* Measurement in X direction taken from the Teflon plate surface: 1 cm should be added to compare to others
SERIES 227887 TA Project: DRESBUS II
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Table 4.14 Extensometers numbering
A/A DAS
Channel Strain gauge
F10 33 F2.1 F9 34 F2.2 F8 35 F2.3 F7 36 F2.4 F6 37 F2.5 F5 38 F2.6 F4 39 F2.7 F3 40 F2.8 F2 41 F2.9 F1 42 F2.10 D4 43 CL9 D3 44 CL10 D2 45 CL11 D1 46 CL12
Figs. 4.97-4.100 show filtered acceleration time histories, while in the Figs. 4.101-4.104 the
maximum horizontal accelerations, obtained along the vertical accelerometer arrays for all
shakes are summarized. The maximum horizontal acceleration recorded on the tunnel was
generally found to be larger than the free field.
Similar to the dry tests observations were made from the tunnel deformations, namely: increase
of the walls deformations reaching the roof slab, increase of the tunnel deformations with the
increase of the input motion amplitude and in phase response of the diagonal deformations (Figs.
4.105-4.108).
The pore pressures were generally increased during shaking (except P3, middle of tunnel's wall).
After shaking pore pressures recorded at P1, P3 continue to increase, while at P2 the pore
pressure tend to decrease indicating a possible flow from higher levels to the tunnel foundation
level.
Fig. 4.113 presents the soil surface settlements, as recorded at three locations by the
displacement sensors. The sensor above the tunnel was probably shifted during EQ4 (reduction
of the settlement).
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A2
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A3
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A4
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A5
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A6
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A7
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A8
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A9
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A10
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A11
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A12
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A13
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A14
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A15
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A16
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A17
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A18
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A19
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A20
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A21
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A22
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A23
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A24
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A26
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A27
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A28
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A29
Fig. 4.97 Maximum Processed acceleration time histories – EQ1
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A2
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A3
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A4
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A5
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A6
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A7
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A8
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A9
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A10
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A11
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A12
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A13
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A14
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A15
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A16
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A17
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A18
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A19
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A20
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A21
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A22
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A23
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A24
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A26
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A27
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A28
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A29
Fig. 4.98 Processed acceleration time histories – EQ2
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0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A2
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A3
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A4
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A5
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A6
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A7
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A8
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A9
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A10
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A11
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A12
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A13
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A14
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A15
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A16
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A17
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A18
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A19
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A20
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A21
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A22
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A23
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A24
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A26
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A27
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A28
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A29
Fig. 4.99 Processed acceleration time histories – EQ3
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0 0.160.320.480.64−0.5
−0.250
0.250.5
A/4
0g
A1 − Input
0 0.160.320.480.64−0.5
−0.250
0.250.5
A2
0 0.160.320.480.64−0.5
−0.250
0.250.5
A3
0 0.160.320.480.64−0.5
−0.250
0.250.5
A4
0 0.160.320.480.64−0.5
−0.250
0.250.5
A5
0 0.160.320.480.64−0.5
−0.250
0.250.5
A6
0 0.160.320.480.64−0.5
−0.250
0.250.5
A/4
0g
A7
0 0.160.320.480.64−0.5
−0.250
0.250.5
A8
0 0.160.320.480.64−0.5
−0.250
0.250.5
A9
0 0.160.320.480.64−0.5
−0.250
0.250.5
A10
0 0.160.320.480.64−0.5
−0.250
0.250.5
A11
0 0.160.320.480.64−0.5
−0.250
0.250.5
A12
0 0.160.320.480.64−0.5
−0.250
0.250.5
A/4
0g
A13
0 0.160.320.480.64−0.5
−0.250
0.250.5
A14
0 0.160.320.480.64−0.5
−0.250
0.250.5
A15
0 0.160.320.480.64−0.5
−0.250
0.250.5
A16
0 0.160.320.480.64−0.5
−0.250
0.250.5
A17
0 0.160.320.480.64−0.5
−0.250
0.250.5
A18
0 0.160.320.480.64−0.5
−0.250
0.250.5
A/4
0g
A19
0 0.160.320.480.64−0.5
−0.250
0.250.5
A20
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A21
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A22
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A23
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A24
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A/4
0g
A25
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A26
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A27
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A28
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A29
Fig. 4.100 Processed acceleration time histories – EQ4
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0 0.075 0.15 0.225 0.30
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.075 0.15 0.225 0.30
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.30.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.101 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.3 0.40.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.102 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2
SERIES 227887 TA Project: DRESBUS II
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0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.2 0.3 0.40.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.103 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3
0 0.125 0.25 0.375 0.50
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.125 0.25 0.375 0.5
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.125 0.25 0.375 0.5
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.125 0.25 0.375 0.5
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.125 0.25 0.375 0.50
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.30.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.104 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F1
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F6
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F1−F6
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F2
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F7
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F2−F7
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F3
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F8
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F3−F8
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F4
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F9
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F4−F9
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D(m
m)
F5
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
F10
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01
t(s)
F5−F10
Fig. 4.105 Walls deformations obtained using a low pass filter – EQ1
SERIES 227887 TA Project: DRESBUS II
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0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.106 Walls maximum deformations obtained using a low pass filter
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D2
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D3
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D4
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.107 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1
SERIES 227887 TA Project: DRESBUS II
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0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.108 Walls maximum deformations obtained using a band pass filter
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0 0.5 1 1.5 2120.36
120.38
120.4
120.42
120.44
t(s)
Po
re p
ress
ure
s(kP
a)
P1
0 0.5 1 1.5 2111.1
111.15
111.2
111.25
111.3
111.35
t(s)
P2
0 0.5 1 1.5 2117.2
117.3
117.4
117.5
117.6
117.7
t(s)
Po
re p
ress
ure
s(kP
a)
P3
0 0.5 1 1.5 2130.38
130.4
130.42
130.44
130.46
130.48
t(s)
P4
Fig. 4.109 Water pore pressures during and after shaking – EQ1
0 0.5 1 1.5 2109.8
109.85
109.9
109.95
110
110.05
t(s)
Po
re p
ress
ure
s(kP
a)
P1
0 0.5 1 1.5 2100.1
100.2
100.3
100.4
t(s)
P2
0 0.5 1 1.5 2109.2
109.4
109.6
109.8
110
t(s)
Po
re p
ress
ure
s(kP
a)
P3
0 0.5 1 1.5 2117.65
117.7
117.75
117.8
117.85
117.9
t(s)
P4
Fig. 4.110 Water pore pressures during and after shaking – EQ2
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0 0.5 1 1.5 2111.35
111.4
111.45
111.5
111.55
111.6
t(s)
Po
re p
ress
ure
s(kP
a)
P1
0 0.5 1 1.5 2102.1
102.2
102.3
102.4
102.5
102.6
t(s)
P2
0 0.5 1 1.5 2110.95
111
111.05
111.1
111.15
111.2
t(s)
Po
re p
ress
ure
s(kP
a)
P3
0 0.5 1 1.5 2120.2
120.25
120.3
120.35
120.4
120.45
t(s)
P4
Fig. 4.111 Water pore pressures during and after shaking – EQ3
0 0.5 1 1.5 2117.6
117.65
117.7
117.75
117.8
117.85
t(s)
Po
re p
ress
ure
s(kP
a)
P1
0 0.5 1 1.5 2107.4
107.6
107.8
108
108.2
t(s)
P2
0 0.5 1 1.5 2115.2
115.4
115.6
115.8
116
t(s)
Po
re p
ress
ure
s(kP
a)
P3
0 0.5 1 1.5 2126.45
126.5
126.55
126.6
126.65
126.7
t(s)
P4
Fig. 4.112 Water pore pressures during and after shaking – EQ4
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0 100 200 300 400 500 600 700 800 9000
2
4
6
8
10
12
14
Sampling point
Set
tlem
ent(
mm
)
S1S2S3
Fig. 4.113 Soil surface settlements
Stabilization circles Northridge
0.1g to 0.3g
Sine wavelet
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4.8 TEST DRESBUS_2_7_1
Fig 4.114 presents the model set up along with instrumentation scheme. The saturation was
scheduled to be performed the week before the test for an anticipated temperature of 16°C in the
centrifuge room. The real temperature in the command room during the test was 18°C leading to
a viscosity between 35 and 39 cSt. The level of the water table was 2 cm over the sand level.
DRESBUS2_7_1: Rigid tunnel ‐Rough surface ‐ Saturated Sand
250mm
400mm240mm
360mm
180mm326mm
360mm
A2
A1
A3
A4
A20
A12
A9 A6 A13A7
A10A11
A8 A5
130mm
130mm
A14A15
20mm
100mm
F5
F1F6
F10
D1 D2D3
D4
S1 S3
800mm
Dry Fontainebleau Sand(Dr=70%)
Model
14mm
y
x
z
S2
Accelerometer Laser displacementssensor
Diagonal extensiometer
Transversal "fork"extensiometers
50mm
5.0mm6.0mm54mm
A23
A24
A21
A22
A25A26
A16
A17
A18A19
Pore pressuresensors
A27
P1
P2 P4 P3
A28 A29
Fig. 4.114 Test DRESBUS_2_7_1 model set up and instrumentation scheme
The test was interrupted by a centrifuge shut down due to a default of the cooling system. The
test stopped before the main shakings.
SERIES 227887 TA Project: DRESBUS II
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Tables 4.12 and 4.13 summarize channels and sensors locations before and after the main test.
The coordinates refer to the reference system presented in Fig. 2.21.
Table 4.12 Sensors numbering and exact positions
Real coordinates at set-up
Real Position after shocksA/A
DAS Channel
Sensor #
Positive Direct X
cm Y
cm Z / top box
cm Z / surface
cm Z / top box
cm Settlement
mm A1 1 68 + pivot A2 2 122 + pivot 17 39 46.2 36 A20 3 123 + top 17 41 46.6 36 A3 4 108 + pivot 16* 40 44.6 34.4 A12 5 104 + pivot 16.5 18.2 32.9 22.7 A4 6 101 + pivot 16* 40.5 33.4 23.2 A27 7 96 + top 16.5* 43.4 33.2 23 A6 8 103 + pivot 16* 45 20.2 10 A9 9 106 + pivot 17 48.5 20 9.8 A13 10 105 + pivot 16.5 19 20.1 9.9 A7 11 95 + pivot 16* 44.5 17.4 7.2 A11 12 100 + pivot 16.8 47.5 12.2 2 A5 13 99 + pivot 16 41 12.4 2.2 A15 14 98 + pivot 16.8 17 12.3 2.1 A8 15 97 + pivot 16 44 14.9 4.7 A14 16 102 + pivot 17 17.5 14.8 4.6 A28 17 124 + top 17* 38.3 12.2 2 A29 18 92 + top 17.5 20.5 12.3 2.1 A26 19 125 + top A25 20 126 + top A21 21 127 + door A22 22 128 + door A24 23 129 + door A23 24 130 + door A16 25 83 + door A17 26 84 + door A18 27 85 + door A19 28 86 + door P1 29 5799 17 52.5 19.1 8.9 P3 30 5798 16* 35.5 17.4 7.2 P2 31 5797 16.5 50 14.5 4.3 P4 32 5801 17.5 40 12.2 2 P5 33 5802 In the air
A10 34 119 + pivot 17 47.2 14.8 4.6
* Measurement in X direction taken from the Teflon plate surface: 1 cm should be added to compare to others
SERIES 227887 TA Project: DRESBUS II
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Table 4.13 Extensometers numbering
A/A DAS
Channel Strain gauge
F10 35 F2.1 F9 36 F2.2 F8 37 F2.3 F7 38 F2.4 F6 39 F2.5 F5 40 F2.6 F4 41 F2.7 F3 42 F2.8 F2 43 F2.9 F1 44 F2.10 D4 45 CL9 D3 46 CL10 D2 47 CL11 D1 48 CL12
Figs. 4.115-4.118 present the obtained filtered acceleration time histories, while in the Figs.
4.119-4.122 the maximum horizontal accelerations are summarized. Some of the acceleration
time histories were “decreasing” during shaking. This observation explains the de-amplification
of the maximum horizontal acceleration from the soil base to the soil surface, as presented along
the vertical accelerometers arrays. Similar with the previous tests observations were made from
the tunnel deformations records, namely: increase of the walls deformations reaching the roof
slab, increase of the tunnel deformations with the increase of the input motion amplitude and in
plane response of the diagonal deformations (Figs. 4.123-4.126).
Figs. 4.127-4.130 summarize the pore pressures records, while Fig. 4.131-4.132 summarize the
recorded soil surface settlements.
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0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A2
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A3
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A4
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A5
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A6
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A7
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A8
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A9
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A10
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A11
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A12
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A13
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A14
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A15
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A16
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A17
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A18
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A19
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A20
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A21
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A22
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A23
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A24
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A26
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A27
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A28
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A29
Fig. 4.115 Processed acceleration time histories – EQ1
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A2
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A3
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A4
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A5
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A6
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A7
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A8
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A9
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A10
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A11
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A12
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A13
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A14
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A15
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A16
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A17
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A18
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A19
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A20
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A21
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A22
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A23
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A24
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A26
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A27
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A28
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A29
Fig. 4.116 Processed acceleration time histories – EQ2
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A2
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A3
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A4
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A5
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A6
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A7
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A8
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A9
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A10
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A11
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A12
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A13
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A14
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A15
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A16
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A17
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A18
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A19
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A20
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A21
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A22
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A23
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A24
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A26
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A27
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A28
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A29
Fig. 4.117 Processed acceleration time histories – EQ3
SERIES 227887 TA Project: DRESBUS II
135
0 0.160.320.480.64−0.5
−0.250
0.250.5
A/4
0g
A1 − Input
0 0.160.320.480.64−0.5
−0.250
0.250.5
A2
0 0.160.320.480.64−0.5
−0.250
0.250.5
A3
0 0.160.320.480.64−0.5
−0.250
0.250.5
A4
0 0.160.320.480.64−0.5
−0.250
0.250.5
A5
0 0.160.320.480.64−0.5
−0.250
0.250.5
A6
0 0.160.320.480.64−0.5
−0.250
0.250.5
A/4
0g
A7
0 0.160.320.480.64−0.5
−0.250
0.250.5
A8
0 0.160.320.480.64−0.5
−0.250
0.250.5
A9
0 0.160.320.480.64−0.5
−0.250
0.250.5
A10
0 0.160.320.480.64−0.5
−0.250
0.250.5
A11
0 0.160.320.480.64−0.5
−0.250
0.250.5
A12
0 0.160.320.480.64−0.5
−0.250
0.250.5
A/4
0g
A13
0 0.160.320.480.64−0.5
−0.250
0.250.5
A14
0 0.160.320.480.64−0.5
−0.250
0.250.5
A15
0 0.160.320.480.64−0.5
−0.250
0.250.5
A16
0 0.160.320.480.64−0.5
−0.250
0.250.5
A17
0 0.160.320.480.64−0.5
−0.250
0.250.5
A18
0 0.160.320.480.64−0.5
−0.250
0.250.5
A/4
0g
A19
0 0.160.320.480.64−0.5
−0.250
0.250.5
A20
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A21
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A22
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A23
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A24
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A/4
0g
A25
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A26
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A27
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A28
0 0.160.320.480.64−0.5
−0.250
0.250.5
t(s)
A29
Fig. 4.118 Processed acceleration time histories – EQ4
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0 0.075 0.15 0.225 0.30
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.075 0.15 0.225 0.30
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.30.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.119 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1
0 0.075 0.15 0.225 0.30
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.075 0.15 0.225 0.3
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.075 0.15 0.225 0.30
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.3 0.40.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.120 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2
SERIES 227887 TA Project: DRESBUS II
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0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.2 0.3 0.4 0.50.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.121 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.3 0.40.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.122 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4
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0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F1
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F6
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F1−F6
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F2
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F7
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F2−F7
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F3
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F8
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F3−F8
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F4
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F9
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F4−F9
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D(m
m)
F5
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
F10
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01
t(s)
F5−F10
Fig. 4.123 Walls deformations obtained using a low pass filter – EQ1
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0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.124 Walls maximum deformations obtained using a low pass filter
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0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D2
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D3
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D4
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.125 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ1
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
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0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ3
0 0.0075 0.0150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.126 Walls maximum deformations obtained using a band pass filter
0 0.5 1 1.5 2110.6
110.8
111
t(s)
Po
re p
ress
ure
s(kP
a) P1
0 0.5 1 1.5 2117.2
117.4
117.6
t(s)
P2
0 0.5 1 1.5 297.1
97.15
t(s)
P3
0 0.5 1 1.5 2258.2
258.3
258.4
t(s)
Po
re p
ress
ure
s(kP
a) P4
0 0.5 1 1.5 2104.5
105
105.5
t(s)
P5
Fig. 4.127 Water pore pressures during and after shaking – EQ1
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0 0.5 1 1.5 2112.6
112.8
113
t(s)
Po
re p
ress
ure
s(kP
a) P1
0 0.5 1 1.5 2117
117.5
118
t(s)
P2
0 0.5 1 1.5 297.6
97.8
98
t(s)
P3
0 0.5 1 1.5 2257.3
257.4
257.5
t(s)
Po
re p
ress
ure
s(kP
a) P4
0 0.5 1 1.5 2104
105
106
t(s)
P5
Fig. 4.128 Water pore pressures during and after shaking – EQ2
0 0.5 1 1.5 2115.5
116
116.5
t(s)
Po
re p
ress
ure
s(kP
a) P1
0 0.5 1 1.5 2117.5
118
118.5
t(s)
P2
0 0.5 1 1.5 298.6
98.8
99
t(s)
P3
0 0.5 1 1.5 2256
256.1
256.2
t(s)
Po
re p
ress
ure
s(kP
a) P4
0 0.5 1 1.5 2104
105
106
t(s)
P5
Fig. 4.129 Water pore pressures during and after shaking – EQ3
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0 0.5 1 1.5 2117.5
118
118.5
t(s)
Po
re p
ress
ure
s(kP
a) P1
0 0.5 1 1.5 2118
118.5
119
t(s)
P2
0 0.5 1 1.5 299.2
99.4
99.6
t(s)
P3
0 0.5 1 1.5 2255.3
255.4
255.5
t(s)
Po
re p
ress
ure
s(kP
a) P4
0 0.5 1 1.5 2104
105
106
t(s)
P5
Fig. 4.130 Water pore pressures during and after shaking – EQ4
0 50 100 150 200 2500
0.5
1
1.5
2
2.5
3
3.5
4
Sampling point
Set
tlem
ent(
mm
)
S1S2S3
Fig. 4.131 Soil surface settlements during swing up
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0 20 40 60 80 100 120 140 160 180 2000
2
4
6
8
10
Sampling point
Set
tlem
ent(
mm
)
S1S2S3
Fig. 4.132 Soil surface settlements during shaking
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5 Interpretation of experimental data
Representative comparisons of recorded soil-tunnel system response are reported in this section.
To this end, soil response is compared in terms of horizontal acceleration amplification, whereas
tunnels response is compared in terms of walls racking deformations.
5.1 CPT DATA DURING TEST SEQUENCE
The results of the CPT tests performed before shaking for all the dry tests are compared in Fig.
5.1. The results variation is within 10% with respect to the mean value, indicating the
repeatability of the soil deposits properties.
0 100 200 3000
50
100
150
200
250
300
Dep
th(m
m)
Force (daN)
DRESBUS2 1 1DRESBUS2 2 1DRESBUS2 3 1DRESBUS2 5 1
Fig. 5.1 CPT test results for the dry sand tests
5.2 RECORDED SOIL AMPLIFICATION
Fig. 5.2 depicts maximum horizontal acceleration, recorded along the free field Array 2 for the
dry test cases, denoting a slight amplification within the soil deposit.
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The corresponding results for the saturated sand are given in Fig. 5.3 showing a considerably
higher scatter with respect to the dry cases.
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ10 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ2
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ3
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ4
DRESBUS 2 1 1DRESBUS 2 2 1DRESBUS 2 3 1DRESBUS 2 5 1
Fig. 5.2 Maximum horizontal acceleration at the soil free field (Array 2) for the dry tests
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0 0.1125 0.225 0.3375 0.450
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ10 0.1125 0.225 0.3375 0.45
0
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ2
0 0.1125 0.225 0.3375 0.450
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ3
0 0.1125 0.225 0.3375 0.450
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ4
DRESBUS 2 4 2DRESBUS 2 6 1DRESBUS 2 7 1
Fig. 5.3 Maximum horizontal acceleration at the soil free field (Array 2) for the saturated tests
5.3 TUNNELS RACKING DEFORMATIONS
The following paragraphs present comparisons of the maximum deformations recorded on the
tunnels walls as affected by (i) the input motion amplitude, (ii) the rigidity of the tunnel and (iii)
the roughness of the tunnel’s external face.
5.3.1 Input motion amplitude effect
Figs. 5.4-5.10 show maximum racking deformations imposed on the tunnels side walls (lsw: left
side wall, rsw: right side wall) for each test case. EQ1, EQ2 and EQ3 refer to the Northridge
record scaled to 0.1 g, 0.2 g and 0.3 g, respectively, whereas EQ4 refers to the sine wavelet (0.3
g, 85 Hz). Generally, the racking deformations are increased with increasing amplitude of the
base excitation in a symmetrical manner between the two side walls of the tunnel section. It is
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noted that the tunnel response recorded during tests DRESBUS_4_2_2 and DRESBUS_2_5_1
was partially corrupted.
0 0.05 0.1 0.150
9.5
19
28.5
38
Dep
th(m
m)
0 0.05 0.1 0.15 0.2
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.4 Maximum racking deformations for different input motion amplitudes – rough flexible tunnel in dry sand (DRESBUS2_1_1)
0 0.05 0.1 0.150
9.5
19
28.5
38
Dep
th(m
m)
0 0.05 0.1 0.15 0.2
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.5 Maximum racking deformations for different input motion amplitudes – smooth flexible tunnel in dry sand (DRESBUS2_2_1)
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0 0.0063 0.0125 0.01880
9.5
19
28.5
38
Dep
th(m
m)
0 0.0063 0.0125 0.0188 0.025
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.6 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in dry sand (DRESBUS2_3_1)
0 0.0063 0.0125 0.01880
9.5
19
28.5
38
Dep
th(m
m)
0 0.0063 0.0125 0.0188 0.025
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.7 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in saturated sand (DRESBUS2_4_2)
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0 0.15 0.3 0.450
9.5
19
28.5
38
Dep
th(m
m)
0 0.15 0.3 0.45 0.6
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.8 Maximum racking deformations for different input motion amplitudes – smooth rigid tunnel in dry sand (DRESBUS2_5_1)
0 0.0063 0.0125 0.01880
9.5
19
28.5
38
Dep
th(m
m)
0 0.0063 0.0125 0.0188 0.025
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.9 Maximum racking deformations for different input motion amplitudes – smooth rigid tunnel in saturated sand (DRESBUS2_6_1)
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0 0.0063 0.0125 0.01880
9.5
19
28.5
38
Dep
th(m
m)
0 0.0063 0.0125 0.0188 0.025
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.10 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in saturated sand (DRESBUS2_7_1)
5.3.2 Tunnel stiffness effect
Notwithstanding the similar deformation pattern, the flexible tunnel sections showed higher
deformation amplitudes compared to the rigid ones.
5.3.3 Soil‐tunnel interface effect
Fig 5.11 compares wall deformations for smooth and rough soil-tunnel interface. The results
refer to the flexible tunnel case embedded in dry sand (tests DRESBUS2_1_1,
DRESBUS2_2_1). A similar deformation pattern is revealed, while larger deformation amplitude
is observed for the smooth surface tunnel under the low-amplitude base excitations (EQ1 and
EQ2). The opposite trend is observed for the high-amplitude motions (EQ3 and EQ4) were the
deformations of the rough surface tunnel are generally larger than the smooth interface tunnel.
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0 0.0375 0.075 0.11250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0375 0.075 0.1125 0.15
0 0.0375 0.075 0.11250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0375 0.075 0.1125 0.15
0 0.0375 0.075 0.11250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0375 0.075 0.1125 0.15
0 0.0375 0.075 0.11250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0375 0.075 0.1125 0.15
RoughSmooth
EQ1 − D(mm)
EQ2 − D(mm)
EQ3 − D(mm)
EQ4 − D(mm)
lsw rsw
Fig. 5.11 Maximum racking deformations for different input motion amplitudes – rough vs. smooth flexible tunnel in dry sand (DRESBUS2_1_1 vs. DRESBUS2_2_1)
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Comparisons of the walls deformations as recorded for the rigid tunnels embedded in saturated
sands are summarized in Fig. 5.12 (test case DRESBUS_2_6_1: smooth tunnel,
DRESBUS_2_7_1: rough tunnel). The wall deformations were generally larger for the rough
tunnel, with the difference being increased with the increase of the input motion amplitude.
0 0.005 0.01 0.0150
9.5
19
28.5
38
Dep
th(m
m)
0 0.005 0.01 0.015 0.02
0 0.005 0.01 0.0150
9.5
19
28.5
38
Dep
th(m
m)
0 0.005 0.01 0.015 0.02
0 0.005 0.01 0.0150
9.5
19
28.5
38
Dep
th(m
m)
0 0.005 0.01 0.015 0.02
0 0.005 0.01 0.0150
9.5
19
28.5
38
Dep
th(m
m)
0 0.005 0.01 0.015 0.02
RoughSmooth
EQ1 − D(mm)
EQ2 − D(mm)
EQ3 − D(mm)
EQ4 − D(mm)
lsw rsw
Fig. 5.12 Maximum racking deformations for different input motion amplitudes – rough vs. smooth rigid tunnel in saturated sand (DRESBUS2_6_1 vs. DRESBUS2_7_1)
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5.3.4 Soil saturation effect
Fig 5.13 presents the effect of the sand saturation on the wall deformations as recorded for the
rigid tunnel having a rough external face (tests DRESBUS2_3_1: dry sand, DRESBUS2_2_1:
saturated sand). The walls deformations found to be systematically larger for the dry sand case.
This observation may be attributed to some extend to the higher sand stiffness of the dry sand
compared to the saturated case.
0 0.0075 0.015 0.02250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0075 0.015 0.0225 0.03
0 0.0075 0.015 0.02250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0075 0.015 0.0225 0.03
0 0.0075 0.015 0.02250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0075 0.015 0.0225 0.03
0 0.0075 0.015 0.02250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0075 0.015 0.0225 0.03
DrySaturated
EQ1 − D(mm)
EQ2 − D(mm)
EQ3 − D(mm)
EQ4 − D(mm)
lsw rsw
Fig. 5.13 Maximum racking deformations for different input motion amplitudes – effect of sand saturation (DRESBUS2_3_1 vs. DRESBUS2_7_1)
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6 Conclusions
This report included a detailed description of the centrifuge tests performed within the SERIES
TA Project: DRESBUS II: Investigation of the seismic behaviour of shallow rectangular
underground structures in soft soils using centrifuge experiments. Experimental procedures and
data processing methods were described followed by a detailed presentation of the complete set
of the recorded data. The preliminary interpretation of the results revealed the following issues:
Maximum soil horizontal accelerations were increased within the soil deposit indicating
base-to-surface soil amplification effects.
In some test cases, maximum tunnel acceleration recorded on the base slab was larger
than the corresponding value recorded on the roof slab. This counterintuitive behavior
may be associated with recording spikes that were observed after filtering.
The horizontal deformations along the tunnels side walls developed in a symmetrical
manner proving the theoretical assumption of racking distortion mode.
The diagonal extensometers recordings showed in-phase diagonal deformations along the
longitudinal axis of the tunnel denoting the plane strain behavior of the model sections.
Rigid tunnels were understandably less deformed during shaking compared to the flexible
sections.
For the specific soil-tunnel systems under investigation, the external face rugosity seems
to have a minor effect on the tunnels deformation, probably due to the small dimensions
of the test models.
Tunnel walls deformations were generally larger for the dry test case compared to the
saturated case. This observation may be attributed to some extend to the higher sand
stiffness of the dry sand compared to the saturated case.
SERIES 227887 TA Project: DRESBUS II
156
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