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Transbay Transit Center ProjectSh i W ll d E ti C t ti
301 Mission Buttress Shoring Wall and Excavation Construction
Structural Assessment
June 8 2010
1
June 8, 2010
• Subsurface conditions and Transit Centre box
• Excavation process
• Movement analyses
• Movement monitoringMovement monitoring
• Summary
1852 Shoreline and Site ConditionsRelative to the DTX and the TerminalRelative to the DTX and the Terminal
3
Borehole Locations and Adjacent 3rd Party Geotechnical Data
Train Box and Superstructure:Transverse Section
Underside of base mat: -41 ft NAVD88
Vertical Section Along Minna Street
Water Level Contours
• Subsurface conditions and Transit Centre box
• Excavation process
• Movement analyses
• Movement monitoringMovement monitoring
• Summary
Construction of train box inside temporary braced shoring wall
40
20
0
Bracing C@ Depth 28ft
Bracing B@ Depth 16.5ft
Bracing A@ Depth 5.5ft
FILL
Bracing C@ Depth 28ft
Bracing B@ Depth 16.5ft
Bracing A@ Depth 5.5ft
Bracing C@ Depth 28ft
Bracing B@ Depth 16.5ft
Bracing A@ Depth 5.5ft
Typical SoilProfileCL-17 (3 ft) CL-18 (20 ft) CL-33 (40 ft)
43ft 43ft 43ft
80
60
40
Dep
th, f
t BAYMUD
43ft 43ft 43ft
-1 0 1 2
Cumulative Lateral
140
120
100
-1 0 1 2
Cumulative Lateral-1 0 1 2
Cumulative Lateral
COLMASAND
Exca
vatio
n
0 20 40 60Distance from Excavation, ft
CL-20 CL-21 CL-35 CL-36
CL-17 CL-18 CL-33 CL-34
SPTCWall
Line 23
Line 22
Displacement, in Displacement, in Displacement, in
MMTProject
BARTProject
1994j
1969/70
Photo courtesy of San Francisco Public Library
Soil-Cement Walls – Sequence of Installationq1) Mixing of First
Primary Panel
2) Mixing of Second Primary Panel
3) Mixing of Secondary Panel Between TwoPanel Between Two Primary Panels
10
DMM Rig during constructability trials Installation of Beamconstructability trials
111111
Typical Cross Lot BracingDeep Excavation Along The EmbarcaderoMuni Metro Turnback Project
Typical Diagonal Bracing of Deep ExcavationsGap Building and EBMUD Wet Weather BuildingGap Building and EBMUD Wet Weather Building
13 13
Many ways of providing internal support t d tito deep excavations
• Subsurface conditions and Transit Centre box
• Excavation process
• Movement analyses
• Movement monitoringMovement monitoring
• Summary
West Base Case I
East Base Case I
• Subsurface conditions and Transit Centre box
• Excavation process
• Movement analyses
• Movement monitoringMovement monitoring
• Summary
Ground and Wall Monitoring Instrumentation
Monitoring ground movements
Extensometer Real time extensometer & inclinometer installationte so ete
Inclinometers and extensometers(sub surfacedisplacements).
Can be real time or manualInclinometer (x, y, 0.002 in/ft)Extensometer (z, +/- 0.01 inch)
Inclinometer and logging deviceInclinometer and logging device
Deep settlement marker and levelling points
Summary
•Established ground and groundwater conditionsS f l t t bilit t i l f h i ll•Successful constructability trials of shoring walls
•Excavation processes identified•Calibrated soil models using numerical analysis g ymethods•Predicted ground movements•General ground and water movement controlsGeneral ground and water movement controls established for general conditions•Shoring wall package is ready for market.
