Construction Stage Analysis for Tunnelling

8/12/2019 Construction Stage Analysis for Tunnelling

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10thMIDAS International Technical Seminar

JaeSeok Yang MIDAS Information Technology

2013. 11. 05

Construction Stage Analysis forTunnelling


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Part 1. Introduction

Part 2. Tunnel construction

Part 3. Simulation of the construction process

Part 4. Project Applications

Part 5. Conclusion

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Geotechnical & Tunnel analysis SystemIntroduction

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Why use numerical methods to analyse tunnel construction?

Simulate the construction sequence

Deal with complex ground conditions

Model realistic soil behaviour

Handle complex hydraulic conditions

Deal with ground treatment (e.g. compensation grouting)

Account for adjacent services and structures

Simulate intermediate and long term conditions

Deal with multiple tunnels


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Can unconventional Tunnel Intersections be modeled?

Yes, tunnels with unconventional connection galleries can be modeled with the esse

ntial tools provided.

All types of T-type/Y-type intercon

nections, curved tunnels, shaft-lat

eral-main tunnel connections, tunnel entrances, even subway station

s can be easily modeled in detail.

Why midas GTS?


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Can Shield TBM be modeled?

Yes, TBM modeling, considering excavation sequences, is available.

Automated and realistic construction st

age definition for sequential activation

and deactivation of excavation segmen

ts, structural parts, loads and boundary

conditions.

Why midas GTS?


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Tunnel Section

B-Spline

Polyline

TunnelSection

Line

3C 3C+I

5C 5C+I

LineArcCircleEllipseParabola

Hyperbola

B-SplinePoylineRectanglePolygonProfile

Tunnel Section

Curve Types

Curve Modeling


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Data Exchange

Import (Geometry)

Export (Geometry) Standards for Data Exchange STEP (STandardfor theExchange ofProduct Model Data)

IGES(InitialGraphicsExchangeSpecification)

STL (STereoLithography)De facto standard for RP

Neutral Format FileASCII (American Standard Code for

Information Interchange)

IGES Geometry

Generated Mesh


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Advanced Geometry Modeling


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Tunnel Modeling Wizard

GTS provides Tunnel Modeling Wizard for simple and regular-type 3D tunnel models.

Tunnel Modeling Wizard automatically generates full analysis data, mesh, loads,

boundary conditionsand construction stages, from the user-defined parameters.

Tunnel Modeling Wizard also provides its own file I/O service to help users

accelerate modeling works for similar models and build their own tunnel templates.

Tunnel modeling Wizard Generated Analysis Model (Mesh, LBC, CS, etc.)


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Tunnel Modeling Wizard

Complete Model Generated by Tunnel Wizard

Front View

Iso View

Core + S/C + R/B

Analysis Data

Result Summary


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Part 5. Conclusion

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Geotechnical & Tunnel analysis SystemTunnel construction

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Open faced shield tunnelling

Schematic view of shielding during tunnel excavation


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Tunnel Boring Machines (TBM)

Schematic view of the TBM


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The sprayed concrete lining (SCL) method

Schematic view of SCL method


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Ground response to tunnel construction

Sources of volume loss (example of the TBM)


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Part 5. Conclusion

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Geotechnical & Tunnel analysis System

Simulation of theconstruction process

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Introduction

Plane strain geometry

Axi-symmetric geometry


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Setting up the initial conditions

If it is known:

Modelling the complete geological history of the site

If it is not known:

Input the conditions appropriate to a greenfield site

(by means of the material unit weight, the pore water pressure

profile and the coefficient of earth pressure at rest, K0)

Simulating any previous construction activities that have occurred

at the site


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Important boundary conditions

The boundary displacement conditions, required to represent the

far field conditions or any symmetry of the problem

Any surface traction

The excavation of solid soil elements

The construction of structural shell elements

The hydraulic conditions at the far field boundaries, the soil strata

interfaces (if an interface is between consolidating and

non-consolidating elements) and the tunnel lining itself


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The 'gap' method

Modelling tunnel excavation

The gap method for modelling tunnel excavation


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The 'convergence-confinement' method


Convergence-confinement method


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ExcavationInitial & Embanking

Drag & Drop

Transient Seepage

Analysis Control

Load Distribution Factors

Tree Structure



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The 'volume loss control' method


Volume loss method


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The use of solid elements

Allows the analyst a very wide range of constitutive models

Maintain an acceptable element shape (defined by the aspect

ratio of length to width)

The use of shell elements

Removes the problem of aspect ratio control

Allows more flexibility in the mesh definition

A structural nature (i.e. shear force, hoop force, and bending

moment)

Modelling the tunnel lining


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Gauging Element Generation

Gauging Element Results

Gauging element

l f h


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Modelling the connections between lining segments

Modelling segment connectionas a moment-free joint


Unrolled and rolled tunnel lining

Si l i f h


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Shell interface element

Input properties of the shell interface element


Input dialog foruser-defined shell interface behavior

Si l i f h


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Shell interface element


Example of shell interface element creation


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Part 5. Conclusion

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Geotechnical & Tunnel analysis SystemProject Applications

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Kings Cross Station

(UK)


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Trans-Hudson

Express & StationCavern(USA)


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Trans-Hudson

Express Dyer AvenueFan Plant (USA)


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Helsinki Subway

Western Expansion(Finland)


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Final Disposal

Facility PosivasONKALO (Finland)


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Part 5. Conclusion

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Geotechnical & Tunnel analysis SystemConclusion

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Summary

A three dimensional engineering processMethods of simulating tunnel construction in plane strain:

the volume loss to be expected; the percentage of load removal

prior to lining construction; or the actual displacement of the

tunnel boundarySegmental linings to open or rotate at their joints, or

sprayed concrete linings to crack

View any prediction of intermediate and long term behaviour

Select constitutive models capable of reproducing field behaviour

FEM can be used to quickly assess the impact of different

influences on tunnelling-induced ground movements

Numerical analysis can incorporate adjacent influences


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Thank you!

Documents

Construction Stage Analysis for Tunnelling