Presentación HW

El espacio subterrneo opcin del futuro WTC CIUDAD DE MXICO, 8 10 OCTUBRE 2014

SESION 4 Metodos Convencionales

Harald Wagner, ITA EXCO Expert 8 Octubre, 2014 17:30 18:10

CTM Structures Strategic Approach

Introduction

Geotechnical Principles

Conceptual Design Phase

Preliminary Design Phase

Tender Design Phase

Final Design Phase

Geotechnical Design

Geotechnical Construction

Geotechnical Report

Baseline Construction Plan

Safety Management Plan

Monitoring

Risk Management

Extraordinary Support

Conclusions

1. Introduction

Classical CTM construction stages for infrastructure tunnel (1998)

WDC - CTM Station (10.000 trees to the future)

CTM Technology

Ground surrounding the Tunnel is considered to be a load bearing structure as full or part of support.

Ground has to be kept in its integrity.

Ground and Ground Behaviour determine basic and additional Support.

Geotechnical Baselines

Baseline 1 Equilibrium Shortly after excavation and

installation of support, the new ground

Equilibrium shall be achieved!

Baseline 2 Safety

Tunnel lining Safety during and after construction needs to be defined until

the end of design life !

Geotechnical Model

Soil

Rock

0

20

60

40

80

100

100

80

60

40

20

str

ess

r0/1

00

tim

eT

4 5 6 7 8 9 10 deformationr20 50

Scheme of r r Curve(after Fenner and Pacher)

Soil

Rock

Radial deformation governing size of excavation section

CTM Metro Stations

Specific advantages of Conventional Mining for Station Design near sensitive and valuable historical Structures

Mined Method allows limitation of number of stress shifts, as every stress shift reduces natural bearing capacity of ground.

Evaluation of different Design Alternatives leads to decision for Station Configuration.

Mined Station Advantages

Virtually unlimited space in the configuration and design of the underground station.

Minimize settlements and deformation of surrounding ground.

Technology to monitor and to limit deformations within calculated prediction.

Metro Station Evolution Phase I 1974 - 1993

1974 - 1976 Subway Bochum, Germany

1975 - 1977 Subway Nuremberg, Germany

1977 - 1982 Subway Munich, Germany

1981 - 1985 Metro Mexico, Mexico

1991 - 1995 Subway Munich, Germany

1986 - 1991 Station Washington, USA

1992 - 1993 Subway Milano, Italy

1991 - 1992 Metro Los Angeles, USA

1993 - 1995 Subway Paris, France

Metro Station Evolution Phase II 1994 - 2005

1992 - 1995 Metro Washington, USA

1994 - 1995 Metro Lille, France

1998 - 2000 Subway San Juan, Puerto Rico

2000 - 2000 Metro New Delhi, India

2000 - 2001 Sound Transit Seattle, USA

1998 - 2001 Subway Stuttgart, Germany

1999 - 2002 East Side Access New York, USA

1998 - 2004 Metro Budapest, Hungary

Metro Bochum Germany 1976

Metro Station Berliner Platz worldwide 1st NATM Metro Station

Metro Nuremberg Germany 1977

Metro Station Lorenz Church - separated tubes near historic towers

Metro Munich Germany 1981

Theresienwiese Station Prototype Multiple Drift NATM Excavation

Metro Mexico Mexico D.F. 1982

Linea 3 Sur - Estacion San Joaquin

Metro Washington DC USA 1991

Fort Totten Station - 1st soft ground NATM Station in North America

Metro Budapest Hungary 2004

Combination of Station Concepts CTM/NATM, C+ C, TBM

BLE CONTRACT 1- Bangkok 2008

Wang Burapha Station (CTM Staked Station)

C&C

TBM

NATM

PHASE 2

PHASE 1

PHASE 3

TRIPLE PHASE

RISK CONTROL

Sanam Chai Station (CTM Binocular Station )

NATM

PHASE 2

PHASE 1

PHASE 3

TBM

C&C

TRIPLE PHASE

RISK CONTROL

Bangkok BLE Elementary Lessons

Wang Burapha and Sanam Chai Stations were designed using

Conventional Tunnelling (CTM/NATM) and constructed using hybrid

solutions.

Experience Contractors proposed to use Roof Piping due to lack

of technological experience and claiming equivalency.

Screening Contractors shall be screened upon implemen- tation of

Qualification Criteria for capabilities in Tender Documents.

Cost Comparing Environmental Impact between different

underground structures, conventional based concepts prevail in urban

infrastructures.

2. Geotechnical Principles

Base theory of CTM/NATM is to view the ground around and on top of the tunnel not only as a load, but also as a load-bearing element of support.

Ground reactions as lining deformations and lining pressures are measured. The stability of the excavation is confirmed by frequent monitoring.

Depending on project conditions (e.g. shallow soft ground tunnel, deep rock tunnel) and results of geotechnical measurements, requirement for Rapid rigid Support or Slim deformable Support is identified.

Contractual Principles

Contractual arrangement requires the most economical type

and amount of support installation in the tunnel.

Ground Classification related to stand-up time of an

unsupported section of the tunnel was the original approach

to conventional tunnel construction.

On base of experience and contractual framework, applicable

ground class needs to be agreed between Contractor and

Engineer at excavation face.

Strategic Development

Project Development of a tunnel shall be subdivided into following stages

conceptual design

preliminary design

tender design (detail design, phase 1)

construction design (detail design, phase 2).

3. Conceptual Design Phase

Scope and verification of design

Selection of preferred alignment from several

alignment studies

Geological and hydrological information to develop

geotechnical characteristics

Validation of anticipated construction method

including environmental aspects

Conceptual cost estimate

Conceptual construction schedule

Conceptual ventilation scheme

4. Preliminary Design Phase

Target to receive approval from the client

Evaluation of site investigation and lab test results

Identification of portal locations and structure

Development of typical cross sections

Decision on tunnel advance methods

Tunnel waterproofing and drainage concepts

Construction concepts, water and power supply,

location of construction roads and muck depots

Detailed construction programme

Revised cost estimate

5. Tender Design Phase

Tender design includes:

Detail design of all structures and incorporation of latest project developments, results of additional site investigations and requirements by the authority.

Update of geotechnical prognosis, support measures drawings, distribution of support classes, detailing of auxiliary construction methods and provision of information as required by the national standards and guidelines.

Scope of tender design includes details of works in order to make exact pricing of each work item feasible.

6. Final/Construction Design Phase

Construction design includes:

The adaptation of the detail design to the particular requirements of the excavation and support methods selected for construction and to the geological/geotechnical conditions encountered in situ is a particular aim of conventional tunnelling contracts conditions found on site.

The production of design drawings used for the construction (e.g. formwork drawings, reinforcement drawings and schedules, fabrication drawings etc.).

Scope of construction design requires detailing of works described in the tender stages in order to make construction feasible.

7. Geotechnical Design

Design has to contain BCP (Baseline Construction Plan. It shall describe expected ground conditions, assumptions, and boundary conditions the design is based on.

BCP shall contain Statements describing which measures cannot be modified during construction

BCP shall contain Criteria for possible modifications and adjustments during construction.

Results of all phases of geotechnical design have to be summarized in a Geotechnical Report.

Steps in Design

Step 1: Determination of Ground Types

Step 2: Determination of Ground Behavior Types

Step 3: Determination of Excavation & Support

Step 4: Geotechnical Report BCP - Plan

Step 5: Determination of Excavation Classes

8. Geotechnical Construction

Geotechnical rock mass parameters have to be collected, recorded, and evaluated to determine the Rock Mass Type.

Monitoring data together with the rock mass type shall determine the Rock Behaviour Type to be determined.

Geotechnical Design and Baseline Construction Plan have to be continuously updated based on findings on site.

Excavation & Support have to be determined based on criteria laid out in BCP

(Baseline Construction Plan) and SFP (Safety Management Plan).

Steps in Construction

Step 1 Verification of Ground Type

Step 2 Verification of Ground Behaviour Type

Step 3 Verification of Excavation and Support

Step 4 Verification of System Behaviour

9. Geotechnical Report

Summary of Results of geologic/geotechnical investigations, interpretation

Rock Mass Types description, associated key parameters

Rock Mass Behaviour Types description, influencing factors, analyses performed, geotechnical model as base for Behaviour Type

Excavation & Support determination, scenarios, analyses applied, results

BCP (Baseline Construction Plan), excavation class determination, distribution along the alignment

Detailed Specifications to the BCP, System Behaviour, measures on site, warning criteria and limits, etc.

10. Baseline Construction Plan

BCP summarizes Geotechnical Design to following information

Geological model, distribution of Rock Mass Types and Behaviour Types

Sections, where specific requirements for construction have to be observed

Fixed excavation and support types (round length, excavation sequence, overexcavation, invert distance, support quality and quantity, ground improvements, etc.)

Measures to be determined on site (presupport, face, face support, ground improvement, drainage, etc.)

Description of System Behavior (behavior during excavation, deformation characteristics, utilization of supports, etc.)

Warning criteria and levels, as well as remedial measures according to the safety management plan

11. Safety Management Plan

SMP shall contain following topics

Design Concept for determination of excavation & support

Criteria for Assessment of Stability based on the knowledge of ground conditions during design

Monitoring Concept with all technical and organizational provisions to allow a continuous comparison between the expected and actual conditions

Safe Crown Excavation & Face Support

BEG Tunnel - Lot 5, Austria

Safe staggered Bench Excavation


Full Cross Section Excavation

BEG Tunnel - Lot 2-1, Austria

Installation Waterproofing Membrane


Invert Arch Reinforcement


Inner Lining Reinforcement


Arch & Invert Final Lining


12. Monitoring

Routine tunnelling shall monitor following State of the Art of Data Evaluation

Tunnelling through Poor Ground shall provide experience from monitoring of problems and solutions.

Proper modelling in design, continuous & adequate monitoring of ground/support interaction forms base for on site decisions.

Monitoring in Construction

Deflection Monitoring

Displacement History Plots

Value of Information from plots

Assuming continuous face advance, displacement rate over

time has to decrease

Displacement acceleration indicates destabilisation, unless

there are ongoing construction activities in the monitored

tunnel section (e.g. bench and invert excavation, or shaping

activities)

Stabilisation is reached after bench and invert excavation

Displacement History

Typical displacement history diagram, showing expected behaviour and indication of destabilisation

Final Displacement

Final displacements extrapolated from few readings, using

previous experience and including the actual geological situation

Deflection Curve

Value of Information of deflection curves

When showing several deflection curves on the same plot,

comparison of displacements along tunnel is possible

Information on the longitudinal extent of tunnel

deformation behaviour is provided

Trends of relative decreasing or increasing ground

behaviour can be verified

Deflection Curve Extrapolation

The extrapolation of deflection curves to the tunnel face and the addition of the resulting

difference ("pre-displacements") to the measured values

Deflection Curve Plot

Typical plot of deflection curves when excavation approaches a "weak" zone

(schematically)

Trend Lines

Value of Information

Trend lines provide an overview of displacement development along tunnel axis, used for extrapolation beyond face

Trend lines used to determine appropriate support type and quantity for comparison of similar deformation behaviour.

Trend lines with increasing displacement tendency can indicate critical situations and must be analysed

Trend line shows settlement beyond face.

Trend Line of Settlement

Trend line of settlement when tunnelling in homogeneous rock mass and

when passing a fault zone (schematically)

13. Risk Management

Risk Register serves for Risk Identification

Different Risks in Design & Construction, e.g.

inadequate design, unforseen ground conditions

Risks are to be prioritized and quantified

Risk Analysis

RA takes measures to avoid double risk counting

RA takes account of correlation between risk types

Quantification of potential cost overruns reflects possibility of increased staff costs

Correlation between unforseen ground condition cost and risk of contractual claims should be estimated

Risk Management Steps

Step 1 Establish objectives and risk appetite

Step 2 Risk identification

Step 3 Risk classification

Step 4 Risk allocation

Step 5 Risk assessment, impact & quantification

Step 6 Identification of mitigation procedures

Step 7 Preparation and update of risk register

14. Extraordinary Support - Samples

Standard Support

Measures are contractually to be installed all along

the length of the tunnel.

Means & Methods should be specified and

designed.

It should be demonstrated when and how

additional support measures respectively

contingency support measures shall be installed.

Additional Support

Designed and specified ground conditions are requiring

standard support measures, in order not to exceed

1.0 x dcrit.

It dcrit represents a threshold value, which is on the very

safe side, for the purpose of defining the value requiring

additional support measures.

Deformation related Support

RE

LE

VA

NT

CR

OS

S S

EC

TIO

N

FO

R M

EA

SU

RE

ME

NT

ACTUAL

DEFORMATION

STRESS RELIEVE

1.0

d =

100%

1.4

d

70%

D/2AL

90%80%

LONGITUDINAL SECTION

0%

4'

Dcrit.

50%60% c

rit.

crit. SS

M

1.8

d

CA

SM

CIG

MA

SM

crit.

- FOR SUPPORT MEASURES SEE INDIVIDUAL DRAWINGS

LIT: ICONMIG 1988 (PAGE 1,531 ff)

ADDITIONAL SUPPORT MEASURE INSTALLATION

-d TRESHOLD DEFORMATION DEFINED TO START

- AL ADVANCED LENGTH

- CIGM CONTINGENCY IMPROVEMENT OF GROUND

- CASM CONTINGENCY APPLICATION OF SUPPORT MEASURES

- ASM ADDITIONAL SUPPORT MEASURES

NOTE: - SSM STANDARD SUPPORT MEASURES

crit.

SUPPORT MEASURES BEYOND GBR

EXAMPLE OF RELATED DEFORMATION

Time & location related deformations with support categories

Decision Matrix

1.81.71.5 1.61.41.2 1.31.1d0.90.7 0.8No. SUPPORT TYPE

SOIL NAILING 21 (Standard)

SHOTCRETE: (10 cm) 4"

ADVANCE LENGTH (AL) 4'

VACUUM LANCES IN INVERT

DEWATERING / PROBE HOLES: 5 WELL POINTS IN TOP HEADING,

PIPE ROOF: 29 pcs, L=50' e=10'

FACE BOLTING: 9 pcs, fibre glass, L=28', in top heading

FACE SEALING: 2" (Total) fibre shotcrete

SPILING: Bar size 9, (1.0 sqin)

LATTICE GIRDERS: on 3' spacing, Type PS 95/20/30

ADDITIONAL SHOTCRETE

ADDITIONAL SOIL NAILS: for AL + 30%

ADDITIONAL SOIL NAILS: 21 (Add.) /3' for 100 % AL

REDUCED ADVANCE LENGTH (AL) 3'

SUPPORT TYPE

ADDITIONAL SOIL NAILS: For 100 % AL as required

SUPPORT TYPE

DIVIDED FACE EXCAVATION

ADDITIONAL SOIL NAILS: for AL + 50% as required

ADDITIONAL SHOTCRETE

PIPE ROOFING

FACE SEALING: 2" (Total) fibre shotcrete

FACE BOLTING: Fibre glass, L=28', in top heading

GROUTING

4b

5

4a

SUPPORT

MEASURES

CONTINGENCY2

3

1b

No.

0

1a

5

SUPPORT

MEASURES

ADDITIONAL

4a

4b

3b

3a

2

0

1b

1a

No.

MEASURES

3

2

STANDARD

SUPPORT1

0

0.80.7 1.41.2 1.3d 1.10.9 crit 1.81.71.5 1.6

0.80.7 0.9 1.1d crit 1.31.2 1.4 1.61.5 1.7 1.8

crit

CROSS SECTION

6 JET GROUTING: improvement of Qpnl

NOTES: - TUNNEL WALKER HAS AUTHORITY TO ADDITIONAL MEASURES AT ANY TIME AS REQUIRED BY FACE CONDITIONS.

- MEASURES CANNOT BE REDUCED WITHOUT CONSENSUS.

DECISION MATRIX

Soft Ground Metro Station

Anchors Shotcrete Observational Approach Sequential Excavation Timely Ring Closure

Flexibel vs. Stiff Approach

Flexible Approach - Ground Arch using

Anchors - Thin SF Shotcrete - Flat Dome - Top Heading Stiff Approach - Steel Ribs & Wire

Meshes - Thick Shotcrete - Tear Drop

Excavation

Classical Binocular Soft Ground Station

Estacion San Joaquin Mexico & Fort Totten Station Washington DC

Station Excavation Phase 3

Metro Washington Fort Totten Station

Side Drift Excavation Phase 4


Multiple Drift Excavation


Penetrating Soldier Pile Portal Wall


Presupporting Steel Pipes


Penetrated Shotcrete Shaft


Heavy anchored, multiple drift X-Section

Sound Transit Seattle Monocular Cross Section

Narrow Tunnels with prestressed Pillar

Parramatta Tunnel, Sydney, Australia

Anchor Support & Multiple Drift

Ia

IIIa

IIIb

Ib

IIa IIb

Metro Budapest, Hungary

15. CTM Conclusions

Ground is viewed as integrated element of support

Ground reactions are measured to confirm stability

Ground should be kept undisturbed

Type of support to allow most economical design

Construction decisions based on Ground Behaviour

Disclaimer

Disclaimer a) The speakers are presenting their own personal views and are not expressing the view of any Organization. b) Papers and documents displayed or handed out during the Event are copyrighted. The participants must observe and comply with all applicable law regulations concerning the copyright.

Underground Space Option of the Future

Ciudad de Mexico, Octubre 8 10, 2014