Diamond Engineer: Tunnel Series Training 2northamerica.midasuser.com/web/...2_1521752588.pdf ·...

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

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