Prepared by example ITA/AITESmaboushook.kau.edu.sa/Files/0053019/files/7097_421-4-BTM.pdf · The example of Alp Transit Project Loetschberg base tunnel ITA/AITES – Training Course

TheThe exampleexample of Alp of Alp TransitTransit ProjectProjectLoetschberg base tunnelLoetschberg base tunnel

ITA/AITES ITA/AITES –– Training Training CourseCourseTUNNEL ENGINEERING TUNNEL ENGINEERING

ITA/AITESITA/AITES

May 6, 2005 11//4040

Prepared by Prepared by ““F.F. VuilleumierVuilleumier and G.and G. SeingreSeingre””

Istanbul Istanbul -- 20052005

5Conclusions Conclusions and and referencesreferences

Chapter 1 :Chapter 1 : Rockburst by TBM excavation

Chapter 2 : Chapter 2 : Face instability with block formation

IntroductionIntroduction : : Loetschberg-Base-Tunnel

ChapterChapter 3 : 3 : On site comparison between TBM and drill-and-blast

Index

2

3

4

1

22//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Introduction

Loetschberg-Base-Tunnelshort presentation

TheThe exampleexample of Alp of Alp TransitTransit ProjectProject 33//4040

22

33

44

55

11

Switzerland builds now 2 new alpine base tunnels

• GothardL = 57 km2015

• LoetschbergL = 34.7 km2007connection withSimplon-tunnel

44//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Functions of the new rail alpine routes

• Integration of Switzerland in european high-speed railway network

• Transfer of alpine freight traffic from road to rail

55//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Loetschberg - Project overview

- Length : 34,7 km- 2 tubes, 65-70 m2

- Total length of all galeries : 88 km

- Altitude max. : 828 m- Construction period :

1995 - 2006- Coming into operation :

2007

66//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Geology

77//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Construction concept

• 10 simultaneous tunnel drives

• Reducing time construction

• Risk management : max. length 10 km

88//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Construction concept : D + B

99//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Construction concept : TBM

1010//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Overall construction programme

1111//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Chapter 1

Spalling during TBM excavation

22

33

44

55

11

1212//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Condition for stress-driven spalling

• Massive Rockmass• Brittle rock• High stress level

(high overburden)• Low confinement

(ratio σ3 / σ1)• Crack damage

initiationσtan max = 0. 3…0.5 σc

Doc. Diederichs

1313//4040The example of Alp Transit ProjectThe example of Alp Transit Project

Stresses on tunnel walls

• Kirsch (1898)• σr = 0• σtan max = 3 σ1 - σ3

• σtan min = 3 σ3 - σ1

- Doc. Hoek, Kaiser and Bawden

1414//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Spalling : stresses orientation

Loestchberg TBM drives• overburden up to

1700 m• σv~ σ1 > σh

• max. stresses on the tunnel wall

- Doc. Martin, Kaiser and Mc Creath

1515//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Stress-driven spalling : example

1616//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Stress-driven spalling : example

1717//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Stress-driven spalling : example

1818//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Problem for TBMGripper pads cannot

be seated on the side wall

1919//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Problem for TBM excavation

the 4 m TBM shield protects the workers

2020//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Support choice by spalling

Spalling• Standard support :

– Swellex-Bolts– Wire mesh (TBM)– Fiber-shotcrete (D+B)

• Bolts on tunnel wall (and on tunnel face by drill-and-blast)

Rockburst• Stored Energy => support

– Yiellding-Swellex orSplitset-Bolts

– Fiber-shotcrete or wire mesh and shotcrete

• High density of bolts on tunnel wall (and on tunnel face by drill- and-blast)

2121//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Support choice by spallingLearning from the first drive

2222//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Chapter 2

Face instability with block formation

22

33

44

55

11

2323//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Face instability with block formation

2424//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Block formation before cutter head

Doc. ARGEMaTrans, TBM drive Raron

Damage at :-Mucking buckets-Disc-cutters-Band-conveyors

Abrasion of cutter-head

2525//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Face instability with blocks formation

• Claim of the contractor

• Influence of stress level and orientation

• Influence of tunnel radius (Kaiser)

• Influence ofschistosity and fractures

2626//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Chapter 3

On site comparison between TBM and drill-

and-blast

22

33

44

55

11

2727//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Choice between TBM – D+B

2828//****TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

First difficulty : Trias zone Raron

•• 10 km OK 10 km OK forfor TBM TBM

•• 150 m Trias 150 m Trias zone too zone too difficult fordifficult for TBMTBM

2929//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

First difficulty : Trias zone Raron

3030//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

First difficulty : Trias zone Raron

>> small exploratory small exploratory gallerygallery onon western western tunneltunnel

>170 m >170 m conventionnal conventionnal prepre--excavationexcavation ofofeasterneastern tubetube

3131//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Choice of excavation’s type

PoliticsPolitics

•• Steg Steg drive readydrive ready to to gogoin 2000in 2000

•• Raron drive ready onlyRaron drive ready onlyin 2001in 2001

> TBM > TBM forfor Steg lateral Steg lateral aditadit

3232//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Other reasons• too short for economic

TBM excavation

• limited place at Portal Raron

=> east tunnel : TBM west tunnel : D + B

Choice of excavation’s type

3333//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

On site comparison between TBM and drill-and-blast

Length 3‘400 m

3434//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

� Lias-limestone, 750 m (22%)� Dogger (Aalenian) - marlschist

and limestone, 850 m (25%)� Quinten (Malm) - hard limestone,

470 m (14%)� Granodiorite, 780 m (23%)� Central Aar-Granite, 570 m

(17%)

Comparison of advance rates

Rock Type TBM (m/d) D+B (m/d)

Lias 6.5 5.6

Dogger (Aalenian) 17.8 7.3

Quinten Limestone 18.5 10

Granodiorite 22.2 8.7

Granite 13.7 10.2

unstableunstable layer in crownlayer in crown

very abrasive rock very abrasive rock and blocksand blocks

3535//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Lias limestone : unstable layer in crown

• Very schistose• Flatly dipping in the

direction of tunnel drive

• Convergence until 60 cm in TBM drive

• Few problems for drill and blast drive (unstable layer fell during blasting)

3636//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Central Aar granite : abrasivity and blocks

• TBM-head had to be repaired 4 times

• Protection of disc-cutters against blocks

3737//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Central Aar granite : abrasivity and blocks

3838//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

Conclusions and references

• Hard rock TBM can drive under moderate spalling conditions=> orientation of grippers ?

• Stress-driven block formation can occur at TBM face under high overburden

• Orientation of schistosity and fractures

22

33

44

55

11

3939//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject

ITA/AITESITA/AITES

Clause de non-responsabilité pour les rapports des groupes de travail de l'AITESL’Association Internationale des Travaux en Souterrain (AITES) publie ce rapport, conformément à ses Statuts, pour faciliter les échanges d’informations afin :

d’encourager l’utilisation du sous-sol au profit du grand public, de l’environnement et du développement durable;

de promouvoir les progrès dans la planification, le projet, la construction, l’entretien, la réhabilitation et la sécurité des tunnels et de l’espace souterrain en rassemblant et confrontant les informations, ainsi qu’en étudiant les questions qui s’y rapportent.

Cependant, l’AITES décline toute responsabilité en ce qui concerne les informations publiées dans ce rapport.

Ces informations :

sont exclusivement de nature générale et ne visent pas la situation particulière d’une personne physique ou morale;

ne sont pas nécessairement complètes, exhaustives, exactes ou à jour ;

proviennent parfois de sources extérieures sue lesquelles les services de l’AITES n’ont aucun contrôle et pour lesquelles l’AITES décline toute responsabilité ;

ne constituent pas un avis professionnel or juridique (si vous avez besoin d’avis spécifiques, consultez toujours un professionnel dûment qualifié).

Disclaimer for the reports of ITA working groups The International Tunnelling Association (ITA) publishes this report to, in accordance with its statutes, facilitate the exchange of information, in order:

to encourage planning of the subsurface for the benefit of the public, environment and sustainable development

to promote advances in planning, design, construction, maintenance and safety of tunnels and underground space, by bringing together information thereon and by studying questions related thereto.

However ITA accepts no responsibility or liability whatsoever with regard to the material published in this report.

This material is:

information of a general nature only, which is not intended to address the specific circumstances of any particular individual or entity;

not necessarily comprehensive, complete, accurate or up to date;

sometimes collected from external sources over which ITA services have no control and for which ITA assumes no responsibility;

not professional or legal advice (if you need specific advice, you should always consult a suitably qualified professional).

4040//4040TheThe exampleexample of Alp of Alp TransitTransit ProjectProject