Monitoring of Tunnels in Urban Areas › files › WTC2007 › W-shop › 10.pdf1/32 The 3rd Training course TUNNELLING IN URBAN AREA Prague, 4-5th May 2007 Monitoring of Tunnels in

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The 3rd Training courseTUNNELLING IN URBAN AREA

Prague, 4-5th May 2007

MonitoringMonitoring of Tunnels in Urban of Tunnels in Urban AreasAreas

MScMSc. Felix. Felix AmbergAmberg(Amberg Engineering(Amberg Engineering LtdLtd.., , SwitzerlandSwitzerland))

ITA - AITES WORLD TUNNEL CONGRESS 2007 PRAGUE

TRAINING MATERIAL PREPARED BY

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5ConclusionsConclusions

RiskRisk ManagementManagement

MonitoringMonitoring

IntroductionIntroduction

MonitoringMonitoring of of UrbanUrban TunnelsTunnels, , ExamplesExamples

Index

2

3

4

1

Monitoring of Tunnels in Urban AreasMonitoring of Tunnels in Urban Areas

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Systematic Monitoring as Part of Risk Management

Can Prevent Catastrophic Failures


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Risk Management


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Technical monitoring of tunnels provides methods and applications of measurements to control and observe entire construction projects.

The monitoring measurements are defined within the risk management process.

Therefore the following slides describe first the process of risk management and then the monitoring of tunnels in urban areas.

Monitoring and Risk Management

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Risk Management


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Risk management is the systematic process of identifying, analyzing and responding to project risks.

Risk management is

• not only a single event

• a continuous process during the entire project.

Therefore the risk control is part of the project life cycle from project initiation to project completion.

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Risk Management


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11 Steps

•Risk Identification

Risk management consists of:

•Risk Responding

•Risk Control

•Risk Management Planning

•Risk Analysis

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Risk Management


Flowchart

Risk Identification

Risk Responding

Risk Management Planning

Risk Analysis

Riskacceptable

New Risks

Risk Monitoring and Control

yes

yes

no

no

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Risk Management


Classifications According to ITA Guidelines

(Quelle: Guidelines for tunnelling risk management: International Tunnelling Association, Working Group No. 2, Eskesen, S.D., Tengborg, P. et al, Tunnelling and Underground Space Technology 19 (2004)

Probability of Occurance

(Frequency)

• Very unlikely

• Unlikely

• Occasional

• Lokely

• Very likely

Impact

(Consequence)

• Insignificant

• Considerable

• Serious

• Severe

• Disastrous

The classifications can be defined according to the specific project.

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Risk Management


Risk Analysis Matrix According to ITA Guidelines

Conse-quency

Fre-quency

insignificant considerably serious severe disastrous

very likely


unwanted unwanted unacceptable unacceptable unacceptable

likely acceptable unwanted unwanted unacceptable unacceptable

occasional acceptable acceptable unwanted unwanted unacceptable

unlikely negligible acceptable acceptable unwanted unwanted

very unlikely negligible negligible acceptable acceptableunwanted

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Risk Mangement


Risk Analysis According to ITA Guidelines

Unwanted: Risk mitigation measures shall be identified. The measures shall be implemented as long as the costs of the measures are not disproportionate with the risk reduction obtained.

Acceptable: The hazard shall be managed throughout th project. Consideration of risk mitigation is not required.

Negligible: No further consideration of the hazard is needed.

Unacceptable: The risk shall be reduced as least to Unwantedregardless of the cost risk mitigation.


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Risk Management


Risk Responding, Possible Strategies

Transfer:

transfer the risk to another party which is then responsible to handle the impact

Mitigate:

reduce the risk to make it more acceptable to the project by reducing the probability and/or the impact

Accept:

accept the risk (normally done for project risk which have a low priority or a low impact)

Avoid:

eliminate the uncertainty or execute the project in a different way 22

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Risk Management


Risk Responding, Mitigation

(Quelle: Int. Tunnelling Association (ITA) and Risk; Parker, H.W.; George Fox Seminar; New York, 2005

Consequences, Impact

Likelihood, Probability, Frequency

Initial risk

Residual risk

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Monitoring


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Technical monitoring consists of measurements and their continuous assessment to control a construction project .

-Technical monitoring is defined as part of the risk responding. The kind of measurements and the locations are defined.

-The measurement results are continuously recorded and assessed during the project as part of the risk control.

The following slides focus on the technical monitoring and describe methods and applications.

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Monitoring


Monitoring by

Investigations and Measurements

• Settlement control by levelling

• Vibration measurements

• Measurements by crackmeters and inclination sensors

• Investigations (geophysicalPrediction, Exploratory Drillings)

• 3D-Reflector survey

• Extensometer-, inclinometermeasurements

• Control of ground water table by piezometers

Monitoring of tunnelstructure and ground Monitoring of the surface

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5ConclusionsConclusions

Risk ManagementRisk Management

MonitoringMonitoring

IntroductionIntroduction

Monitoring of UrbanMonitoring of Urban Tunnels, ExamplesTunnels, Examples

Index

2

3

4

1


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Example Uetliberg Road Tunnel


Overview

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2 tubes (each 4.4 km)Cross-cut with pedestrian access every 300 mCross-cut with vehicular access every 900 mSOS niches every 150 m

2 tubes (each 4.4 km)Cross-cut with pedestrian access every 300 mCross-cut with vehicular access every 900 mSOS niches every 150 m

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Selected Excavation Method: Core Method

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Section under Landikontunnel

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Section under Landikontunnel

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Extensometer

Vibration measurements Convergency measurements

Tube Chur Tube Basel

Prisms (3D Optical Survey)

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Example PTS-Tunnel Zurich Airport


Overview

PTS Tunnel

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PTS and Road Tunnels

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Defined Risk Areas

ApronsRunway Bravo

(planned)

Runway 10/28Apron (planned)

Terminal Midfield

Cut and Cover Midfield Tunnel Construction ø 5.40 m

Undercrossing Terminal A

PTS-Station

Terminal A

PTS-Station

Airside Center

Tube 1

100 m

0 m

2 00 m

3 00 m

400 m

5 00 m

600 m

70 0 m

800 m

88 2 m

Legend :

Starting Pit, Exit

TBM-Heading, general

Aircontrol Infrastructurcanal

Taxiways, Aprons

Undercrossing Terminal A

Exit Pit

Runway 10/28

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Excavation in Soft Ground with Hydroshield

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Defined Risk Areas, Undercrossing Terminal A

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Construction Pit

Foundation of existingTerminal

Auxiliary Gallery (yellow)

PTS Tunnel

PTS Tunnel

Wells, Pillars

PTS Tunnel

PTS Tunnel

Wells, Pillars

PTS Tunnel

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Example Circle Line, Stage 4+5, Singapore


Top View

Service lines(electricity, gas, water

Cut and coversection

Tunnels

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Outer Tunnel

Inner Tunnel

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Predicted Ground Settlements

Predictedgroundsettlements in [mm]

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4550

2520

40

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Monitoring of Settlements by Levelling

Settlement marker(electrical cables)Settlement marker(electrical cables)

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Monitoring of the Tunnel under Construction

Optical prism

Strain gauge

Load cell

Inner tunnelOuter tunnel22

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Example Dobrovskeho Road Tunnel, Brno, CZ


DobrovskehoTunnel

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Tunnel

Westportal

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West Portal

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Cross section 10

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Documents

Monitoring of Tunnels in Urban Areas › files › WTC2007 › W-shop › 10.pdf1/32 The 3rd Training course TUNNELLING IN URBAN AREA Prague, 4-5th May 2007 Monitoring of Tunnels in