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Angel Francisco MartinezApplication Engineer
MIDAS NY
Diamond Engineer: Tunnel Series
Training 2
01 Introduction
02 Construction Stages
03 Demo
04 Post -Processing
Content
Introduction
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About MIDAS
2D vs 3D tunnels with soil springs
Structural analysis gives importance to the uncertainty of load, acting on the structure. Hence, it conducts the member design for the largest member force obtained by combining various results systematically
2D vs 3D tunnels w/ ground elements
Ground analysis focuses more on the uncertainty of construction step and material itself, it is important to understand physical state inside the ground. As a result, solid elements need to be used in modeling to reflect the ground shape and construction situation; and non-linear anisotropic materials and in-situ stress states need to be considered to reflect the actual on-site conditions as much as possible.
Ground displacements associated with tunnel excavations occur in vector directions X-Y-Z,
thus to accurately represent ground behavior during tunnel excavation processes, detailed 3D numerical analysis is vital.
WHY model Tunnels in 3D FEM?
Modeling tunnels in 3D is becoming more attractive because of
limitations of the 2D modeling and because it captures the response of tunnel excavations more accurately.
1-8
Define analysis conditions and
run the high performance analysis
자동요소망생성
Modeling Analysis section
Automatic generation of shared
surfaces function
Check shared surfaces
Hybrid Mesh generationCheck results
Work flow for FEM analysis
[Import or automatically generate 3D
layers through actual field data]
Construction stage analysis
Section
Construction Stages
Stage1 Original ground
Stage2 Excavation
Stage3 SIG placing
Stage4 Box Construction
Stage5 Banking
Stage6 Additional Load
Analysis Results
Y-dir. Displacement diagram
Failure Diagram
Vertical Stress Diagram
Axial Force Diagram
3D Analysis considering construction stages when constructing Open Cut Tunnel
Stability during construction stages applying SIG placing method for reviewing the appropriateness and stability of foundation
Model from Training 1
Static to Sequential Excavations
Open static model
Terrain and strata
w/tunnel
4 tunnel lining segments
and rock bolts
1-12
Static Results for ground and support structures
Total Ground Displacements Total Tunnel Displacements
Axial forces on liningAxial forces on rock bolts
Show CS stages of model
Show CS stages of model
The LDF keeps track of the Internal Forces of a deactivated element and loads it in stages according to the factor assigned for each construction stage, rather than loading it all at once.
Show CS stages of model
The ground stress from the non-linear analysis results in the previous stage is coupled and slope stability analysis is conducted.
CS Analysis Case
Construction stage analysis
Excavation 1
Excavation 1
Excavation 2
Excavation 2 Final Stage
Final Stage
Wizards
(Modeling Assistants)
Wizard for easy construction stages set up
Wizard
Wizard
• Use CS wizard to efficiently define the construction stages. • Remove and Activate sets in sequence.
1
2
Wizard
Stage Simulator
Wizard
Check the defined construction stage as a video. It can be used in analyses that incorporate construction stages (Static/Slope analysis, Seepage/Consolidation analysis).
Tunnel Wizard
Tunnel Wizard
Input Mesh Size and soil properties.
Tunnel Wizard
Results
Tunnel Wizard
Demo
3D tunnel connection
Post-Processing
Results
Total Ground Displacements
Total Tunnel Displacements
Mirror Image
Results
Axial forces on liningStresses on lining
Iso- Volume- Max Displacements
Material Status• Plastic Status of Ground Element• Safety Result (Mohr-Coulomb) Calculate Factor of Safety for each element based on MC
failure criteria. In case that Safety Factor is less than 1.2, it can be identical with plastic
failure region.
Results
Results
Results
Results
3D-2D WizardWhen checking the results after 3D analysis, use the cut section & clipping function to check the arbitrary section result contours.
Multi-Stage Animation
Flight Simulation
Results
The Perspective view function from the View toolset below can be used to check the interior information and results of a 3D model.
Time History Probe
Dynamic Report
Results
Save the model information before analysis and the result information after analysis as a 3-dimensional
PDF document. Adjusting the 3D view on the PDF document and checking the cross-section information,
similar to the operations in the program, is possible. Hence, the 3D model/analysis result information can
all be checked on one PDF document without the model/result files.
Conclusions
• Tunnels have wide range of analysis and excavation methods.
• FEM allows for more accurate representation of all local conditions and coupling of multiple types
of analysis.
• 2D is advantageous when terrain is simple and tunnel segment is straight only.
• The 3D FEM allows for accurate simulation of terrain and sequential construction process.
• Modeling in 3D can be more time consuming and should be carried out after it was determined 2D
model has hit limit.
Assignment 2
Tunnel Wizard
Start File
Tunnel Wizard
General
Tunnel Wizard
Shotcrete and Rock Bolts
Tunnel Wizard
Excavation
Tunnel Wizard
Mesh
Tunnel Wizard
Mesh
Tunnel Wizard
Analysis Case
Tunnel Wizard
Results
Review for training 2:
Post Processor & Wizards
http://northamerica.midasuser.com
Send to: [email protected]
3D CS Tunnel
Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
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