Tunnel Failure

up to cto er

Catalogue of Notable Tunnel Failure Case Histories

( O b 2012)

Civil Engineering and Development Department

The Government of the Hong Kong Special Administrative Region

(up to October 2012)

Prepared by Mainland East Division Geotechnical Engineering Office

ublic attention. Even for the cases re orted, usuall onl

p p y y

Foreword

This catalogue of notable tunnel failures is primarily based on published information. Both overseas and local cases involving collapse or excessive deformation of the ground are included. For contractual and other reasons, there are relatively few cases reported in technical publications, and those reported are usually of such scale or seriousness that they have received public attention. Even for the cases reported, usually only limited information is available. Apart from the cases included, readers can find other information on tunnel failure in the list of General References given at the end of this catalogue.

This catalogue is a live document that will be updated from time to time as further information becomes available.

details. Clients and works a ents are advised to im lement

Foreword

The main purpose of the catalogue is to disseminate information and promote awareness on tunnel failures which could pose a danger to life and property. The possible causes of the failures, the geotechnical problems and the lessons learnt, where these are known, are outlined in the catalogue. Readers should refer to the source reference documents quoted for details. Clients and works agents are advised to implement effective geotechnical risk management measures in the planning, investigation, design and construction of their tunnel projects.

Division Workin Grou on Cavern and Tunnel En ineerin and

g p g g

Foreword

The first edition of the catalogue was issued in February 2007 and was put together by Mr W Lee, supervised by Mr K J Roberts. The second edition issued in March 2009 was prepared by Ms L Y Pau, supervised by Mr L P Ho. This third edition was prepared by Ms L Y Pau, supervised by Mr K S Chau. GEO staff, members of the Hong Kong Institution of Engineers Geotechnical Division Working Group on Cavern and Tunnel Engineering and other individuals have contributed to this Catalogue. All contributions are gratefully acknowledged.

Foreword

If any information in this catalogue is found to be inaccurate or out-of-date, please contact the Chief Geotechnical Engineer/Mainland East of the Geotechnical Engineering Office, Civil Engineering and Development Department, 101 Princess Margaret Road, Ho Man Tin, Kowloon, Hong Kong.

N F Chan Chief Geotechnical Engineer/Mainland East

Geotechnical Engineering Office Civil Engineering and Development Department

October 2012

. un c n ergroun , ermany,

6 M i h U d d G 1980

Tunnel Failures – List of Overseas Cases

1. Green Park, London, UK, 1964

2. Victoria Line Underground, London, UK, 1965

3. Southend-on-sea Sewage Tunnel, UK, 1966

4. Rørvikskaret Road Tunnel on Highway 19, Norway, 18 March 1970

5. Orange-fish Tunnel, South Africa, 1970

6. Munich Underground, Germany, 1980

7. Holmestrand Road Tunnel, Norway, 16 Dec. 1981

8. Gibei Railway Tunnel, Romania, 1985

9. Moda Collector Tunnel, Istanbul Sewerage Scheme, Turkey, 1989

10. Seoul Metro Line 5 - Phase 2, Korea, 17 Nov. 1991

11. Seoul Metro Line 5 - Phase 2, Korea, 27 Nov. 1991

12. Seoul Metro Line 5 - Phase 2, Korea, 11 Feb. 1992

13. Seoul Metro Line 5 - Phase 2, Korea, 7 Jan. 1993

14. Seoul Metro Line 5 - Phase 2, Korea, 1 Feb. 1993

15. Munich Underground, Germany, 27 Sept. 1994

16. Heathrow Express, UK, 21 Oct. 1994

17. Los Angeles Metro, USA, 22 June 1995

18. Motorway Tunnels, Austria, 1993 - 1995

19. Docklands Light Rail, UK, 23 Feb. 1998

20. Athens Metro, Greece, 1991-1998

21. Lærdal Road Tunnel on European Highway E 16, Norway, 15 June 1999

27. Shanghai Metro, China, 2003

22. Sewage Tunnel, Hull, UK, 1999

23. Taegu Metro, South Korea, 1 Jan. 2000

24. Channel Tunnel Rail Link, UK, Feb. 2003

25. Météor Metro Tunnel, France, 14 Feb. 2003

26. Oslofjord Subsea Tunnel, Norway, 28 Dec. 2003

27. Shanghai Metro, China, 2003

28. Tunnel Failure, Japan, 2003

29. Guangzhou Metro Line 3, China, 1 April 2004

30. Singapore MRT, 20 April 2004

31. Kaoshiung Rapid Transit, Taiwan, 29 May 2004

32. Oslo Metro Tunnel, Norway, 17 June 2004

. , , .

aos ung ap rans t a wan ec

33. Kaoshiung Rapid Transit, Taiwan, 10 Aug. 2004

34. Hsuehshan Tunnel, Taiwan, 1991-2004

35. Barcelona Metro, Spain, 27 Jan. 2005

36. Lausanne M2 Metro, Switzerland, 22 Feb. 2005

37. Lane Cove Tunnel, Australia, 2 Nov. 2005

38 K hi R id T i T i 4 D 2005 38. Kaoshiung Rapid Transit, Taiwan, 4 Dec. 2005

39. Nedre Romerike Water Treatment Plant Crude Water and Potable Water Tunnels, Norway, 2005

40. Hanekleiv Road Tunnel, Norway, 25 Dec. 2006

41. Stormwater Management and Road Tunnel (SMART), Malaysia, 2003 – 2006

42. Sao Paulo Metro Station, Brazil, 15 Jan. 2007

43. Guangzhou Metro Line 5, China, 17 Jan. 2008

44. Langstaff Road Trunk Sewer, Canada, 2 May 2008

45. Circle Line 4 Tunnel, Singapore, 23 May 2008

46. Hangzhou Metro Tunnel, China, 15 Nov. 2008

47. Cologne North-South Metro Tram Line, German, 3 March 2009

48. Brightwater Tunnel, USA, 8 March 2009

49. Seattle’s Beacon Hill Light Rail, USA, July 2009

50. Cairo Metro Tunnel, Egypt, 3 Sept. 2009

51. Shenzhen Express Rail Link, 27 March 2011, 4 May 2011 and 10 May 2011

52. Hengqin Tunnel, Macau, 19 July 2012

Tunnel Failures – List of Hong Kong Cases

1. MTR Modified Initial System, Prince Edward Station, Nathan Road, 12 Sept. 1977

2. MTR Island Line, 22 Hennessy Road, 1 Jan. 1983

3. MTR Island Line, Shing On Street, Shau Kei Wan, 23 July 1983

4. MTR Island Line, 140-168 Shau Kei Wan Road, 16 Dec. 1983

5. 5. Kowloon Southern Link Contract KDB 200, Canton Road, 21 Oct. Kowloon Southern Link Contract KDB 200, Canton Road, 21 Oct. 2006

6. Kowloon Southern Link Contract KDB 200, Salisbury Road, 3 June 2007

Overseas Cases

Green Park, London, UK, 1964

• Background • Tunnel (Green Park to Victoria) driven through London Clay

using drum-digger shield

• The failure • Inflow of sand and gravel, burying most of the shield

Clay & Takacs (1997)

• Possible cause of failure • The crown of the shield penetrated through the London Clay

layer into sand and gravel

• Source • Clay & Takacs (1997)

Green Park, London, UK, 1964

• Clay & Takacs (1997)

n ow o san an grave

Victoria Line Underground, London, UK, 1965

• Background • Tunnel (300m long and 3.7m internal diameter) driven through

London Clay using hand-shield and lined with cast-iron segments under a disused railway marshalling yard

• The failure •• IInflow of sand and gravel f d lfl d

Clay & Takacs (1997) Civil Engineering and Development Department

• Possible cause of failure • The shield was ineffective in supporting the overlying ground

Victoria Line Underground, London, UK, 1965

SouthendonSea Sewage Tunnel, UK, 1966

• Background • Tunnel driven through London Clay (40m long and 1.35m in

diameter)

• The failure • Water inflow into the tunnel

• Possible cause of failure • The tunnel intersected the bottom of an abandoned 600mm

diameter well

SouthendonSea Sewage Tunnel, UK, 1966

• The to of the shaft on the round surface

Rørvikskaret Road Tunnel on Highway 19, Norway, 18 March 1970

• Background • Road tunnel 726m long and 8m wide constructed by the drill-and-blast

method • The failure

• Tunnel face collapsed and a 100m high cave-in shaft from the tunnel up to the ground surface was created

• The top p of the shaft on the ground g surface had a dimension of about 25m x 50m

• Although soft material was hauled out from the tunnel during the spring in 1971, cave-in continued from the shaft until autumn 1972.

• The cave-in zone extended 30m along the tunnel and the total volume of material hauled out from the tunnel was about 75,000m3

Karlsrud (2010)

• Pro ramme dela ed for more than 3 ears

• Possible cause of failure • Preliminary investigation carried out without any drilling • Probe drilling was not performed during tunnelling • No stabilization measures to support a large swelling clay section

before blasting

• Consequences • Programme delayed for more than 3 years • Double the cost of the tunnel compared to the estimated cost

• Emergency and remedial measures • Installation of corrugated steel vault, steel tubes and 500mm thick

concrete lining was not successful • The cave-in ceased after filling of about 3,000m3 concrete into the

shaft to form a plug from the tunnel up to 10m above the crown and another 4,000m3 of sand and stone from the top of the shaft above the concrete plug

ar sru

• Lessons learnt • The importance of the adequate ground investigation to identify if

weak ground is present and to provide measures to support the weak ground before tunnel excavation

• Source • K l d (2010) • Karlsrud (2010)

Orangefish Tunnel, South Africa, 1970

• Background • Tunnel designed to carry irrigation water from the Orange River

(80km long and 5.3m in diameter, 1,200m above sea level) • Tunnelling using the rail-mounted drill and blast method and lined

with insitu concrete

• First failure – Heavy water inflow • Water inflow of about 55,000 litres/min into the tunnel at 14 bars • Entire 1.6km tunnel section flooded within 24 hours

• Possible cause of failure • The tunnel passed through a shallow anticline and intersected a

fissure, about 75mm wide, almost perpendicularly

Orangefish Tunnel, South Africa, 1970

• Second failure – Fire • Methane gas ignited by a blast • No explosion occurred as the gas did not reach the explosive

concentration • The fire burnt for about 6 month

• Possible cause of failure • Methane gas from a methane bearing fissure entered the tunnel

during excavation

Munich Underground, Germany, 1980

Construction Today (1994b)

• Background • New Austrian Tunnelling Method (NATM) construction of twin 6m

diameter tunnels

• The failure • 10m wide, 14m deep sinkhole • 10m wide, 14m deep sinkhole

• Possible causes of failure • Local variation in geology with reduction in marl cover to 1-1.5m

and led to overstressing of the sprayed concrete temporary lining

• Consequences • Delay to works

• Remedial Measures • Void was backfilled with crushed rock and cement and pressure

grouted grouted

Source • Construction Today (1994b)

Holmestrand Road Tunnel, Norway, 16 Dec. 1981 • Background

• Road tunnel 1.78km long and 10m wide tunnel constructed by the drilland-blast method

• The failure • A minor cave-in from the face and

partly from the crown occurred during the the process of moving the steel process of moving the steel formwork for cast concrete lining forward to the face

• Possible cause of failure • A weak fault zone was encountered • No spiling bolts ahead of the face to

support the weak ground

Karlsrud (2010)

combination with fibre reinforced

Holmestrand Road Tunnel, Norway, 16 Dec. 1981 • Consequences

• More time (5 hours extended to 25 hours) required for hauling out and concreting the foundation for the mould

• Lessons learnt • Spiling bolts ahead of the face in

combination with fibre reinforced sprayed concrete, rock bolts, and reinforced ribs of sprayed concrete are required at the fault zones with extremely poor rock mass quality

• Source • Karlsrud (2010)

Karlsrud (2010)

Gibei Railway Tunnel, Romania, 1985

• Background • Railway tunnel 2.21km long and 9m in diameter

• The failure • “Compact” fissured clay layer failed suddenly, allowing water

inflow >600 litres/min into the tunnel

• Possible cause of failure • The tunnel penetrated a lens of waterlogged fine-grained sand

just above the crown

Gibei Railway Tunnel, Romania, 1985

Moda Collector Tunnel, Istanbul Sewerage Scheme, Turkey, 1989

• Background • Tunnel constructed by Tunnel Boring Machine (TBM)

• The failure • Fine soil flowed into the tunnel forming a hole in the road as the

TBM went through the rock into the soft ground

• Possible cause of failure • The tunnel intersected a hidden area of soft clay

Moda Collector Tunnel, Istanbul Sewerage Scheme, Turkey, 1989

Seoul Metro Line 5 Phase 2, Korea, 17 Nov. 1991

Lee & Cho (2008)

• Background • Construction of Seoul Metro tunnel near Majang by drill and blast

method

• The failure • After blasting : daylight collapse up to ground surface involving • After blasting : daylight collapse up to ground surface, involving

the embankment of a river • 20m x 15m and 4m deep crater at the ground surface • Water from river flowed into the tunnel

• Possible cause of failure • Thin weathered rock cover • Inflow of soil and groundwater

chemical grouting

• Consequences • Roads collapse and gas mains

fractured

• Remedial measures • Backfilling the crater with soil

followed by cement grouting and chemical grouting

• Lessons learnt • Insufficient ground investigation • Unexpected groundwater inflow • No tunnel face stability analysis • No consideration of blasting effects

closed to weathered zone with shallow cover

Lee & Cho (2008) Civil Engineering and Development Department

• Source • Lee & Cho (2008) • Madrid (1996) • Shin et al (2006)

Lee & Cho (2008)

am as ng

10:40 : bl ti

• Background • Construction of Seoul Metro tunnel near Dangsan by drill and

blast method

• The failure • 27 November 1991

10:40am : blasting 4:00pm : rock falls at the tunnel face

10:00pm : soil and groundwater inflow into the tunnel

• 28 November 1991 3:20am : substantial daylight collapse up to ground surface forming a 25m diameter crater

Seoul Metro Line 5 Phase 2, Korea,

27 Nov. 1991

• Possible cause of failure • Weathered granite at the face

and high permeability soil

• Consequences • Three buildings collapsed • Several water mains gas • Several water mains, gas

pipes and sewerage were broken

The Government of the Hong Kong Special Administrative Region Lee & Cho (2008)

zone w s a ow cover

• Lessons learnt • Insufficient ground investigation • Unexpected groundwater inflow • No tunnel face stability analysis • No consideration of blasting effects closed to weathered

ith h ll zone with shallow cover

Seoul Metro Line 5 Phase 2, Korea, 11 Feb. 1992

Lee & Cho (2008)

• Background • Construction of Seoul Metro tunnel near Youido by road header

• The failure • Significant inflow of groundwater • About 4.5 tonnes of soil flowed into tunnel • 38m wide x 6m deep crater at the ground surface

o owe y cement grout ng an

• Possible cause of failure • Weathered granite at the tunnel

face and high permeability soil

f ll d b i dfollowed by cement grouting and chemical grouting

• Lessons learnt • Insufficient ground investigation • Unexpected groundwater inflow • No tunnel face stability analysis

Seoul Metro Line 5 Phase 2, Korea, 7 Jan. 1993

Lee & Cho (2008)

• The failure

• Background • Construction of Seoul Metro tunnel near Yongdungpo by drill and

blast method

• The failure • Tunnel collapsed after removing spoil • Tunnel collapsed starting from the left side of the crown • 900m3 of loose material flowed into the tunnel and water inflow of

up to 300 litres/min recorded

eme a measures

R di l

• Possible cause of failure • Weathered granite at the tunnel

face • High groundwater pressure

•• Remedial measures • Backfilling the crater with soil

• Lessons learnt • Insufficient ground investigation • Unexpected groundwater inflow • No tunnel face stability analysis • No consideration of blasting effects closed to weathered zone

with shallow cover

Lee & Cho (2008)

• The failure

• Background • Construction of Seoul Metro tunnel near Anyangcheon by road

header

• The failure • Daylight collapse when weathered granite found at the tunnel

face • Groundwater flowed into the tunnel • 60m wide oval shaped area subsided

onsequences

• Possible cause of failure • Weathered granite and alluvium

at the tunnel face • High groundwater pressure

• C• Consequences • Six heavy plants buried

Lee & Cho (2008)

• Lessons learnt • Insufficient ground investigation • Unexpected groundwater inflow • No tunnel face stability analysis

Munich Underground, Germany, 27 Sept. 1994

• Background • 7m diameter tunnel supported by

sprayed concrete lining • The tunnel was assumed to be

beneath a clay layer overlying water-bearing gravel and groundwater would not be drawn down

• The failure • Quick inflow of water and ground

materials • Large subsidence crater quickly

filled with groundwater

Construction Today (1994a) • 20m wide, 18.5m deep crater Civil Engineering and Development Department

Consequences

• Possible causes of failure • Layer of marl separating groundwater bearing layers was

much thinner than originally assumed • Sand-infilled cracks in the marl layer acted as preferential

pathways for water

• Consequences • Bus fell into the crater • Three passengers killed • 30 people injured

Civil Engineering and Development Department Construction Today (1994a)

• Remedial measures • Bored-pile wall to form a shaft • Excavation inside the shaft for rescue • Tunnel driven again using compressed air

• Sources • Sources • Boos et al (2004) • Construction Today (1994a) • Ground Engineering (1994)

Heathrow Express Tunnel, UK, 21 Oct. 1994

Ground Engineering (2008) ICE (1998b)

• The failure

• Background • NATM in London Clay

• The failure

• 10m diameter crater formed

ICE (1998b)

• Differential settlement induced at ad acent buildin s

• Possible cause of failure • A series of design and management errors combined with

poor workmanship and quality control

• Consequences • Differential settlement induced at adjacent buildings • Services Terminal 4 halted for one month • Remedial measures caused chaos at Heathrow Airport • Recovery cost £150M (3 times original contract sum)

0 to +0.5m

0 to -1m

-1 to -2m

-2 to -3m

GROUND SURFACE CONTOURS LEGENDS

Central Terminal Area Settlement Contours

• Remedial measures • Backfilled with 13,000m3 concrete

However much en ineers are ressured to build uickl and

• Lessons learnt • Measures to ensure safety must be planned • Do not lose sight of critical technical issues in the pursuit of time

and cost reduction • Whilst a number of factors contributed to the collapse, half of them

were matters of management • However much engineers are pressured to build quickly and • g p q y

cheaply, the industry will be judged by its own failures

• Sources • Ground Engineering (2000) • HSE (1996, 2000) • ICE (1998b, 1999)

1996 report 2000 report

e ow sur ace

Los Angeles Metro, USA, 22 June 1995

• Background • Re-mining/remedial works to

realign an existing TBM tunnel (6.7m diameter, 25m deep), which had been bored off line

• Hard siltstone overlain by alluvium with groundwater level 10-12m below surface

• The failure • 25m deep sinkhole caused by

collapse of south bore • Serious cracking observed in

temporary lining of north bore Civil Engineer International (1995)

onsequences

• Possible causes of failure • Failure occurred during removal of segmental lining in tunnel

roof and relining of tunnel to correct the horizontal alignment • Unexpected ground conditions in the alluvium • Fractured water mains (unconfirmed)

•• Consequences • 30m length of a four lane road (Hollywood Boulevard) affected

leading to road closure • Collapsed 250mm water main possibly contributing to failure • Broken gas pipe • Evacuation of local residents

• Remedial measures • Steel rings installed in tunnel either side of the collapse • 3,300m3 of grout to fill void and stabilise area • Road resurfacing

• Source • Civil Engineer International (1995)

Motorway Tunnels, Austria, 1993 1995

• Background • Tunnel constructed in sandstone and shale with fault zones

by the drill & blast method • Tunnel divided into 4 sections, namely T1 – T4 • T1 - 376m long; T2 - 562m; T3 – 2,760m and T4 – 1,230m

• Failures at T4 in 1993 • About 130 overbreak incidents with total volume of 1,461m3,

maximum deformation of 120mm measured in the tunnel • 200m3 of loose material collapsed after a blast, resulting in

water inflow of up to 450 litres/min

Motorway Tunnels, Austria, 1993 1995

• Two failures at T3 in 1995 • 650m3 of loose material flowed into the tunnel, water inflow of up

to 1,500 litres/min recorded • Radial movement of rib of about 300mm occurred and water

inflow of up to 1,500 litres/min recorded

Docklands Light Rail, UK, 23 Feb. 1998

ICE (2004) ICE (1998a)

• Background • Tunnel constructed for Docklands Light Rail (diameter 5.2m) by

earth pressure balance TBM

• The failure • 22m wide and 7m deep crater formed in the grounds of George

Green School

ICE (1998a)

n ows up o m away ro en y e s ower o mu an

Wi d t 100 b k b th h f d d

• Possible causes of failure • Insufficient overburden above the tunnel • High pressure within tunnel causing blow out failure

• Consequence •• Windows up to 100m away broken by the shower of mud and

stones released

• Lesson learnt • To require specific assessments / calculations to demonstrate

the adequacy of factor of safety against blow out failure

• Sources • ICE (1998a)

• ICE (1998a) • ICE (2004)

Athens Metro, Greece, 19911998

IMS IMIA

rate ran in from 1.6m to 18m er da based on 18-hour- er-da

• Background • Construction of the Olympic Metro under a turnkey contract

(estimated cost about 2 billion ECUs) • Construction started in November 1991 and operation in 1998 • TBM (by Mitsubishi) used for construction of 11.7km long, 9.5m

diameter tunnels located at a depth of 15-20m (with penetration rate ranging from 1.6m to 18m per day based on 18g g p y -hour-perp -day y shift, depending on the ground conditions)

• Cut and cover, supported by soldier piles, struts and prestressed anchor tiebacks for 6.3km long tunnels and stations

• NATM for other short auxiliary tunnels and oval-shaped stations where existence of buried antiquities precluded open excavation

e n ense y wea ere an g y ec on se zones o en an

• The failures • Roof collapses of appreciable size often occurred • Large and occasionally uncontrollable overbreaks for TBM

• Possible causes of failure • Ravelling of the ground seems to be due to insufficient strength in

th i t l th d d hi hl t t i d f Ath ithe intensely weathered and highly tectonised zones of Athenian schist (which is a flysch-type sediment consisting of thinly bedded clayey and calcareous sandstones with alterations and subjected to intense folding, thrusting, faulting and fracturing)

• Large muck openings of the TBM cutterhead which cannot adequately control muck-flow (the cutterhead operates in the open air, i.e. under atmospheric pressure)

• Consequence • Major delay in TBM tunnelling

• Remedial measures • Cavities caused by the TBM overbreaks was backfilled by grout

(which sometimes reached the ground surface)

• Source • IMIA • IMS • Kavvadas et al (1996) • Mihalis & Kavvadas (1999)

• Background • Road tunnel at 1,100m depth,

24.5km long and 9m wide constructed by the drill-and-blast method

Lærdal Road Tunnel on European Highway E 16, Norway, 15 June 1999

• The failure • A cave-in involving 17m length of

tunnel and extending up to about 11-12m above the crown

• The volume of the failed rock mass was estimated to be 1,2001,500m3

The Lærdal Tunnel

Ch.11080

CAVE IN

DEBRIS

1200-1500m3

Karlsrud (2010)

• Possible cause of failure • Poor communication : the driller did not inform the engineer about

abnormal drilling rate encountered

• Expansion of the swelling clay under high stress to water during drilling of the rock bolts

• The combination of the swelling of the clay and high stress produced a squeezing effect, which resulted in gradual weakening of the rock mass in the tunnel

• Consequences • The crew was evacuated in time and no one was hurt • About 10 days delay in the excavation works and cost increased for

the remedial works

• Emergency and remedial measures

• Reinforced ribs of sprayed concrete in addition to layers of sprayed concrete and rock bolts were installed just behind the cave-in zone

The Lærdal Tunnel Cave in zone

700 m3 concrete

• Rock material was hauled into the tunnel building up a barrier up to 2m below the crown and concrete was pumped through a steel pipe to fill the void above the debris

• Debris was gradually hauled out with step wise installation of rock anchors and sprayed fibre reinforced concrete

Debris

1200-1500 m3Concrete Debris hauled out

Karlsrud (2010)

• Swelling of clay in condition of high stress could provide a

• Lessons learnt • The importance of good communication between the driller and the

engineer • Importance of having good understanding of the geological

conditions and their influence on the stability • Swelling of clay in condition of high stress could provide a

squeezing effect and result in weaking of the rock mass in a tunnel

• Source • Karlsrud (2010)

Sewage Tunnel, Hull, UK, 1999

Boos et al (2004)

• Water and sand ingress

• Background • Construction of a 10.5km long underground sewer by earth

pressure balance TBM (diameter 3.85m) supported by reinforced concrete segmental lining

• The failure • Water and sand ingress • Tunnel subsided by 1.2m causing serious subsidence at surface

• Possible cause of failure • Fluctuation of groundwater level caused by tidal effects resulting in

vertical movement of the tunnel tube causing opening of joints

• Reconstruction of tunnel using sprayed concrete

• Consequences • Damage to buildings, roads and utility lines • TBM had to be abandoned

• Emergency and remedial measures • Ground freezing • Reconstruction of tunnel using sprayed concrete

• Source • Boos et al (2004)

Taegu Metro, South Korea, 1 Jan. 2000

Boos et al (2004)

• Background • Construction of underground Taegu Metro

• The failure • Failure of diaphragm wall • Excavation pit caved in • Excavation pit caved in

• Possible causes of failure • Rapid fluctuation of groundwater level caused movement of

unidentified gravel and sand strata • Additional loading on diaphragm wall was not considered in design

• xcavat on p t ac e

E i i b kfill d

• Consequences • Bus buried and bus driver seriously injured • Three passengers killed • Neighbouring buildings suffered considerable damage

• Remedial measures • Excavation pit backfilled • Subsoil grouted and diaphragm wall strengthened

Channel Tunnel Rail Link, UK, Feb. 2003

ICE (2003)

orme n e groun e n a row o

• Background • Tunnelling using TBM (diameter 8.2m) • Boring at a depth of 21m

• The failure • 10m diameter and 20m deep void

f d i h d b hi dformed in the ground behind a row of f houses

• Possible cause of failure • The vibration from the TBM may have

caused the nearby wells (30m deep and 1.8m diameter) to collapse

ICE (2003) Civil Engineering and Development Department

• Consequence • Three uncharted wells collapsed

• Remedial measures • The voids were backfilled with grout

• Source • ICE (2003)

Météor Metro Tunnel, France, 14 Feb. 2003

Dubois & Rat (2003)

• Background • Construction of Météor

Metro Tunnel in Paris

• The failure

• The failure • About 3,000m3 of

sedimentary deposits collapsed underneath a school, occupying an area of 400m2 on plan

Dubois & Rat (2003)

• The school had to be closed for a ear affectin 900 students

• Possible cause of failure • Not known

• Consequences • No casualty • The school had to be closed for a year affecting 900 students

• Source • Dubois & Rat (2003)

Oslofjord Subsea Tunnel, Norway, 28 Dec. 2003

• Background • Three major failures and many minor failures occurred at a road

tunnel during in service

• The failure • First failure occurred on 28 December 2003: about 20m3 of crushed

and weathered rock involving with clay, which came down from the and weathered rock involving with clay, which came down from the crown went through the frost insulated water shielding vault and down to the carriageway

• Second failure involved about 3m3 of heavily weathered rock, which came down from the springline and fell down to the invert

• Third failure involved 2-3m3 of completely weathered rock, which fell down from the crown and rested on top of the water shielding vault

Third failure

First failure

Karlsrud (2010)

• Possible cause of failure• The humidity behind the vault constructed for frost insulated

water shielding was high and the high content of swelling clay inthe weathered rock started sucking water and expandedgradually over a long period of time

• Consequences

• Consequences• Closure of the tunnel for more than 3 months for extensive

repairs and upgrading of the tunnel support

• Emergency and remedial measures• Complete removal of the vault before installing additional rock

support including fiber reinforced shotcrete, rock bolts andreinforced ribs of sprayed concrete

• Lessons learnt• The importance of proper geological mapping and rock mass

classification• The need to identify swelling minerals and the potential of

deterioration of strength in weathered rock• The importance of adequate support design for long-term

• The importance of adequate support design for long-termstability in weathered rock

• Source• Karlsrud (2010)

Shanghai Metro, China, 2003

Boos et al (2004)

• Background• Expansion of the Shanghai Metro (上海地鉄) Line 4 crossing

beneath the Huangpu River (黃埔江)• Two parallel tunnel tubes constructed by earth pressure balance

• The failure• Failure occurred during construction of a cross passage• Massive ingress of water and material at the face at a depth of 35m• Several metres ground subsidence

• Possible cause of failure • Failure of ground freezing unit

• Consequences• High rise office buildings seriously damaged• Flood protection dyke on the river badly damaged

Tunnel Failure in Japan, 2003

Takahashi (2010)

• The failure• Ground collapse of an avalanche type containing cobbles, gravels

and water took place at the point 900m away from the tunnel portal• A large crater was observed at the ground surface about 130m

above the tunnel

The Government of the Hong Kong Special Administrative RegionTakahashi (2010)

• Possible cause of failure• Existence of high groundwater

pressure• Decrease in cover of the mud-

stone layer• Water path created by the

investigation drillhole

Filling with foam concrete

• Consequence• Programme delayed for about 2

• Emergency and remedial measures• Filling the cave-in area by foam

concrete• Grouting under the collapse area• Boring for drainage from the tunnel

Takahashi (2010)

• Lessons learnt• The importance of adequate ground investigation before

tunnelling• The importance of investigations and observations during

construction for adopting appropriate support measures

• Source

• Source• Takahashi (2010)

Guangzhou Metro Line 3, China, 1 April 2004

ChinaDaily (2004)

• Background• Construction of a 58.5km long underground metro in which

45.6km is a single-tube shield TBM

• The failure• Failure of a diaphragm wall

• Failure of a diaphragm wall

• Possible cause of failure• Rapid fluctuation of groundwater level due to the heavy rainfall• Complicated geology including a layer of swelling soil

• Consequences• A three-storey building collapsed and sunk into the ground• Collapse of nearby underground water mains

• Remedial measures• Backfilled with crushed rock and cement

• Source• ChinaDaily (2004) • Soufun (2004) • Longhoo (2004)

Singapore MRT, 20 April 2004

Government of Singapore (2005)

• Background• An open cut tunnel excavated for Singapore MRT’s new Circle Line • Design and build• Excavated trench of 15m wide and 33m deep mainly in marine clay

with some fluvial clay supported by 0.8-1.0m thick diaphragm wall which is 35-45m deep without rock socket

• Steel struts: 4-5m horizontal and 3m vertical spacing

• Steel struts: 4-5m horizontal and 3m vertical spacing• Bottom-up construction • Jet grouted base slabs

• Layer 1-1.5m thick at 28.5m below ground• Layer 2-3m thick at 33.5m below ground (Layer 2 not yet

constructed when collapse occurred)

• The failure• 9th level of struts being installed when

collapse took place• Unusual cracking and groaning noises heard

early in the morning (6 hours)• Loud cracking noise heard in the afternoon, 15

minutes before collapse

minutes before collapse• Collapse plan area was 100m by 130m• Settlement up to 15m• Diaphragm walls displaced• Steel struts mangled

Government of Singapore (2005)

• Possible causes of failure• Under-design of the strut-waler connection in the strutting system• Incorrect use of Finite Element Method• No proper design reviews• Disregard of different warnings, for example, excessive wall

deflections and surging inclinometer readings

deflections and surging inclinometer readings• Poor construction quality• Ineffective instrumentation and monitoring system• Failure to implement risk management

• Consequences • Part of Nicoll Highway, Singapore’s major east-west harbour-front

road, destroyed• Four workers killed• Several others injured • 15,000 people and 700 businesses affected

• 15,000 people and 700 businesses affected• Three offices and retail towers at risk from further ground movement• Damage of a gas service line, resulting in an explosion and fire• A storm drain damaged

• Remedial measures• Rescue and backfilling• Structurally disconnected the Merdeka Bridge• All contracts of the Circle Line put on hold• All contracts to carry out checks and review of design and

construction of temporary works• All Professional Engineers to confirm in writing the adequacy of

• All Professional Engineers to confirm in writing the adequacy of their designs

• All designs to be independently checked by the Building & Construction Authority

• Lessons learnt• This is a need for robust design, risk management, design review

and independent checking, purposeful back analysis, an effective instrumentation, monitoring and interpretation regime, an effective system of management of uncertainties and quality during construction, corporate competencies and safety management

• The safety of temporary works is as important as that of

permanent works and should be designed according to established codes and checked by competent persons

• Main Source• Government of Singapore (2005)

Kaohsiung Rapid Transit , Taiwan, 29 May 2004

Lee & Ishihara (2010)

• Background• Chemical Churning Piles (CCP) of

350mm diameter installed as guide wallsfor the diaphragm wall construction

• Soil improvement works by the use ofSuper Jet Grouting (SJG) method at thereception area for break-out operations

• The diaphragm wall panels were first

• The diaphragm wall panels were firstcored through by chain saw according tothe face-shape of the shield tunnelmachine and manual power tool wasused to disassemble the reinforcedconcrete residual inside the coring holes

• EPB Tunnel Boring Machine 500mmaway from the wall face awaiting forbreak-out and invert leakage started

• The failure• Sinkhole of about 10m in diameter formed at the ground surface• Ground settlement influence zone ranging from 40m to 50m in

diameter with maximum settlement from 500mm to 1,500mm.• Several rings of tunnel segmental linings were damaged

Settled Area of Ground Surface

The Government of the Hong Kong Special Administrative Region Lee & Ishihara (2010)

Chemical Churning Pile (CCP)

Soil Improvement Zone

Diaphragm Wall

Possible Collapse Zone

Soil Improvement Zone

Leakage spot

Tunnel Boring Machine

Path of Leakage

• Possible causes of failure • Progressive development of unexpected cracks inside the soil

improvement zone resulting in groundwater leakages in the reception area as a result of piping and/or hydraulic fracturing

• Leakage paths at the interfaces between Chemical Churning Pile (CCP) and the diaphragm wall, CCP and Super Jet Grout (JSG) materials, or inside the lower portion of the JSG body

(JSG) materials, or inside the lower portion of the JSG body

• Chloride assault and deterioration of CCP, which were installed two years before the wall breaking process, had significant effects on the integrity and water tightness at the interfaces

• The highly sensitive and erodible soil dispersed around the SJG might have been disturbed due to the application of highly pressured water jet in the grouting process

• Possible causes of failure • Mechanical and/or vibration disturbances occurred during the wall

breaking process leading to serious cracks and fissure development inside the deteriorated CCP and defective SJG blocks

• Unfavourable sub-surface conditions which consisted of silty sands and sandy silts with water contents almost reaching their liquid limits

• Consequences

• Consequences • Adjacent buildings were damaged

• Emergency and remedial measures• Stabilizing the ground by piling-up

sand bags in front of the tunnelface to reduce leakage, backfillingthe sinkhole and grouting thetunnel crown and invert

• Advancing the TBM further toreduce the gap between the D-wall

reduce the gap between the D-walland the tunnel

• Installation of steel frames toreinforce the damaged ringsegments

• Source• Lee & Ishihara (2010)

• Background• Metro line tunnel 1.3km long and 7m wide connecting with an old tunnel

Oslo Metro Tunnel, Norway, 17 June 2004

Karlsrud (2010)

Planned concrete wall

Cave in area

• The failure• At the junction where the two tunnels met in an acute angle, tunnel

cave-in after removal of most part of the rock pillar between thetunnels

Karlsrud (2010)

m iljo\d iv\2000\ah-1.pp t

Removed pillar

New tunnel Old tunnel

Span 18-20m after cave-in

• Possible cause of failure• Unfavourable direction of the bedding planes in relation to the

geometry and span of the tunnels• Over excavation of the rock pillar and the removal of the

remaining rock pillar and old concrete wall before the plannedconcrete pillar was constructed

• Consequence• Programme delayed for about 3 months

• Programme delayed for about 3 months• Cost implication: extra cost of the remedial works

• Emergency and remedial measures• Filling up the whole opening by concrete above the fallen debris• Installation of 10m long cable anchors together with permanent

support of 200mm thick lining of reinforced sprayed concrete,reinforced ribs of sprayed concrete and additional 6m long rockbolts

• Lessons learnt• The importance of adequate ground investigation• The need to follow the sequence of rock support installation in

accordance with the design plans during construction

• Source

Kaohsiung Rapid Transit, Taiwan, 10 Aug. 2004

• Background• Construction of the Kaohsiung Rapid

Transit Blue & Orange Lines in Kaohsiung City

• The failures

• First collapse on 29 May 2004 underneath a street

• Second collapse in mid June 2004• Third collapse on 13 July 2004 with

formation of a large sinkhole• Fourth collapse on 10 Aug 2004

Taiwan Info (2004)

• Possible cause of failure• Possible adverse ground and groundwater conditions

• Consequences• First collapse - Several buildings affected and 100 people

evacuated • Third collapse - Three residential buildings evacuated and

Kaohsiung Rapid Transit, Taiwan, 10 Aug. 2004

• Third collapse - Three residential buildings evacuated and significant disruption to water/electricity supply

• Fourth collapse - No casualty, one building affected and part of the works suspended

• Source• Taiwan Info (2004)

Hsuehshan Tunnel, Taiwan, 1991-2004

TANEEB (2005)

• Background• Construction of 12.9km long and 4.8m diameter Hsuehshan

Tunnel in Taiwan (雪山隧道) • Works commenced in 1991 and completed in 2004• Comprised 2 main tunnels (East & Westbound) and a pilot tunnel• Eastbound by TBM method (July 1993 to Sept. 2004)• Westbound by TBM method (July 1993 to April 2004)

• Westbound by TBM method (July 1993 to April 2004)• Pilot tunnel by drill & blast method (July 1991 to Oct. 2003)

Westbound Eastbound

Pilot TunnelTANEEB (2005)

• The failures• Eastbound

• 28 collapses occurred• Westbound

• TBM badly damaged due to tunnel collapse and groundwater inflow of 45,000 litres/min into the tunnel

• Pilot Tunnel

• Pilot Tunnel• 8 collapses occurred

• Possible causes of failure• Unexpected difficult geology with fractured rock and massive

inflows of water• 6 major faults found along the tunnel alignment

• Consequences• Eastbound

• Failure in May 1993 affected 56 buildings and 73 families• Westbound

• 11 men died• Pilot Tunnel

• 13 stoppages

• Source• TANEEB (2005)

Barcelona Metro, Spain, 27 Jan. 2005

European Foundations (2005)

• Background• Tunnel for Barcelona Line Five Metro Extension• Tunnelling using NATM

• The failure• 30m wide and 32m deep crater formed

• 30m wide and 32m deep crater formed

• Possible cause of failure• A “hidden” vertical fault located 1m behind the sprayed concrete

lining

• Consequences• 2 five-storey buildings and a smaller one demolished• More than 50 families made homeless

• Remedial measures• The void was backfilled with grout of about 2,000m3

• The void was backfilled with grout of about 2,000m3

• Source• European Foundations (2005)

Lausanne M2 Metro, Switzerland, 22 Feb. 2005

Tunnels & Tunnelling (2005)

• Background• Tunnel (6km long, approximately 10m wide x 7m high) for

Lausanne Metro M2 Project (cost US$472M) in Switzerland• Tunnelling using an Eickhoff ET 380-L roadheader

• The failure

• Collapse in area of soft ground (lake deposits)• 50m3 of material displaced into the tunnel at a depth of 12m,

leading to a crater at the surface

• Possible cause of failure• Tunnel driven through a pocket in the glacial moraine, causing

sudden inflow of groundwater

• Consequences• People in two buildings, a supermarket and a food outlet in

commercial district evacuated when their cellars collapsed• No injuries reported

• Remedial measures• A curtain of 11 piles constructed ahead of the collapsed face with

• A curtain of 11 piles constructed ahead of the collapsed face with grouting to strengthen the ground and limit further flow of material into the tunnel

• The void was backfilled with 800m3 of glass-sand (recycled glass)

• Source• Tunnels & Tunnelling (2005)

Lane Cove Tunnel, Australia, 2 Nov. 2005

• Background• Twin NATM tunnels (7m high, 8.1 wide and 3.6km long)

constructed under Lane Cove Tunnel Project in Sydney

• The failure• Collapse occurred during breakout for a ventilation tunnel from

• Collapse occurred during breakout for a ventilation tunnel from the running tunnel

• A 10m by 10m, 25m deep crater formed in the ground between a 3-storey high residential building and a highway exit ramp

• Possible causes of failure• Possible “rock slippage”• Ground investigation did not identify dyke at the tunnel

intersection• Under designed rock bolts due to increased effective span at

intersection of adit and tunnel

• Consequences• A 3-storey building partially collapsed and 47 residents

evacuated• A water main burst• Citybound road closed

• Remedial measures• The void was backfilled with

1,400m3 of concrete• Continual monitoring

• Sources

• Sources• Golder (2005)• Ground Engineering (2005)• Ground Engineering (2006a)• Ground Engineering (2006b)• ICE (2006)• NNN (2005)• SMH (2005)

ICE (2006)

Kaohsiung Rapid Transit, Taiwan, 4 Dec. 2005

TT (2005)

• Background• Construction of Kaohsiung Rapid Transit (KRT) Orange Line at

the junction of Chungcheng Road and Tashun Road in Kaohsiung City

• The failure• Failure occurred during excavation of an underground sump pit at

• Failure occurred during excavation of an underground sump pit at a cross passage (33m below ground) underneath an existing reservoir

• A 30m by 20m, 4m deep trench initially formed on 4 Dec. 2005 and was collapsed to form a 50m by 30m, 10m deep crater at the road surface

• This was the 10th reported failure of the KRT project• Another crater (10m diameter, 7m deep) formed at another

location on 10 Dec. 2005

• Possible cause of failure• Massive water seepage from a reservoir

• Consequences• Chungcheng Road (a major trunk road) closed for a week• The nearby Linkang railway line temporarily suspended• A 100m long section of tunnels and utilities damaged• Cracks found at 20 nearby residential buildings

• Remedial measures• The crater was backfilled with about 2,800m3 of soil/rock and

concrete 20 hours after the accident• The damaged sections of the KRT tunnels needed to be re-

constructed• Cost of the remedial measures estimated to be up to NT$500M

(US$15M) excluding reconstruction of the damaged sections of the KRT tunnels

• Sources• TVB News (2005)• TT (2005)• SP (2005)• ST (2005)• Sun (2005)• WWP (2005)

• WWP (2005)• OD (2005)• TKP (2005)• MP (2005)

TVB News (2005)

• Background• The tunnel works were completed in

1980. Two tunnels of 3m width forcrude water and potable watersupply were constructed inPrecambrian highly metamorphicgneisses

Nedre Romerike Water Treatment Plant, Crude

Water and Potable Water Tunnels, Norway, 2005

gneisses• In some areas, the gneiss is highly

weathered and is partly transformedto clay

Karlsrud (2010)

• The failure• The failure was progressive for more than 25 years resulting in

blockage of the crude water tunnel• A major failure occurred in the crude water tunnel in winter 2005 and

the weathered rock failed• Two major progressive failures occurred in 2007 and about 200m3 and

30-40m3 rocks fell each time

Section A-A

Karlsrud (2010)

Open joint which released a large block

• Possible cause of failure• Lack of mapping of weakness zones containing swelling clay

resulting in insufficient rock support

• The humidity in the water tunnel probably causing a gradualexpansion of the swelling clay which resulted in detachment of the

expansion of the swelling clay which resulted in detachment of therock

• Consequences• About 150, 000 people affected by disruption in water supply

• Emergency and remedial measures

• Due to the limited access in the crude water tunnel, only manuallyreplacement and redistribution of the debris downstream from thecave-in areas could be carried out by divers when the water levelwas lowered

Lessons learnt

• Lessons learnt• The importance of proper rock mass classification, detailed

mapping of weakness zones and weathered rock, andimplementation of adequate rock support

• Background• The tunnel was supported with a

combination of rock bolts and steelfiber reinforced concrete

• The failure• A section of tunnel caved in10-11

years after excavation

Hanekleiv Road Tunnel, Norway, 25 December

years after excavation

• Possible cause of failure • Unfavourable geometry with joints

almost parallel to the tunnel axis.• The rock bolts installed mainly

parallel to the rock joints and with limited influence on the stability

Karlsrud (2010)

• Consequences• About 200m3 of debris fell down from the crown and the tunnel

was closed for about 6.5 months

• Emergency and remedial measures• Casting concrete lining and installing about 4,000 rock bolts

Hanekleiv Road Tunnel, Norway, 25 December

• Lessons learnt• Lack of qualified engineering geologist at the site to carry out

mapping and design during the tunnel construction

Stormwater Management and Road Tunnel

(SMART), Malaysia, 2003 - 2006

Limestone

Siow, M. T. (2006)

• Background• 9.7km long and 13.26m diameter tunnel driven through karst

formation by slurry shield TBM

• The failure

• The failure• 37 incidents within 8 km of tunnel excavation

• Possible cause of failure• Adverse geology and karst conditions

Siow, M. T. (2006)

McFeat-Smith (2008)

• Source• Siow, M. T. (2006)• McFeat-Smith (2008)

Sao Paulo Metro Station, Brazil,

15 Jan. 2007

Gulp (2007)

15 Jan. 2007

• Background• New Austrian Tunnelling Method (NATM) was used to excavate a

18.5m diameter 45m long section station tunnel• The tunnel failure occurred close to a junction with a 40m

diameter, 40m deep access shaft

• The failure• Collapse of the station tunnel and partial damage to the access

shaft• The rate of settlement at the tunnel crown increased rapidly and

reached 15mm to 20mm two to three days before the failure

• Possible cause of failure• Failed to account for the geology of the site; fractured rock

located over the excavation • The lack of sufficient supports in the roof and side walls of the

excavation

• Consequences

15 Jan. 2007

• Consequences• Several vehicles dropped into the 30m-deep hole• Seven persons killed

• Remedial measures• Stabilized the section of tunnel with extensive reinforcement• A system of anchors extending 32m into the soil was put in place

and the excavation through the section was performed after pre-grouting

• Source• ICE (2008)• Gulp (2007)

15 Jan. 2007

Guangzhou Metro Line 5, China,

17 Jan. 2008

Sina (2008a)

AD (2008)

17 Jan. 2008

• Background• Construction of a cross passage between two tunnel boring

machine tunnels

• The failure• Collapse of the cross passage tunnel

• Collapse of the cross passage tunnel

• Possible cause of failure• Groundwater flowed into the tunnel

• Consequences• Cave-in at the road, about 100m2 on plan• No injury

• Remedial measures• Crater backfilled with concrete

• Source• AD (2008a)• Sina (2008a, 2008b)

17 Jan. 2008

• Sina (2008a, 2008b)

Langstaff Road Trunk Sewer, Toronto, Canada

2 May 2008

Wallis, P (2009) Discharge through the screw conveyor of the EPBM

• Background• Tunnelling by EPBM for the construction of the sewer tunnel

• The failure• About 1,800 m3 of liquefied mud flowed into the tunnel over a 48-

hour period through the tail brushes causing the tunnel and the TBM to sink by more than 3m and collapse

2 May 2008

TBM to sink by more than 3m and collapse• A deep sinkhole formed at the ground surface

• Possible causes of failure • Damaged wire brushes of the tailseal of the EPBM were the

catalyst for initiating the whole sequence of the failure events • Highly saturated very fine sands and silts under 1.5 bars of

groundwater pressure

• Consequences• The road above the excavated area closed• Major delay to the project • The TBM was buried

• Emergency and remedial measures• Filling the sinkhole with unshrinkable fill (low strength concrete)

2 May 2008

• Filling the sinkhole with unshrinkable fill (low strength concrete)• Areas of continuing subsidence were stabilized with sand infill• Bulkhead was built about 300m behind the TBM to control the

infow• Water main repaired and road repaved

• Source• Wallis, P (2009)• Wallis, S (2008)

Circle Line 4 Tunnel, Singapore, 23 May 2008

Property Highlights of Singapore (2008)

• Background• Construction of Circle Line 4

tunnel by 6m diameter slurry mixshield TBM

• The failure

• The failure• Cave-in at Holland Road

approximately 8m diameter x 3m deep

• Possible cause of failure• Loose ground

Property Highlights of Singapore (2008)

• Consequences• Temporary suspension of water supply

• Remedial measures• Crater backfilled with concrete

• Source• Property Highlights of Singapore (2008)

Hangzhou Metro Tunnel, China, 15 Nov. 2008

AD (2008b)

• Background• Construction of Hangzhou Metro

• The Failure• Failure of a series of continuous walls of 800mm thick

constructed by cut-and-cover method forming a 21m wide x 16m deep excavated area

deep excavated area

• Consequences• A 75m long section of road collapsed and 11 vehicles fell into the

16m deep excavation• A 600mm diameter water main was broken • Water from the nearby river flowed into the collapsed area

• Consequences• Three 3-storey buildings seriously damaged and needed to be

demolished• Two 110kV cables were damaged • 8 persons died, 13 persons missing (as of 19 Nov. 2008) and 11

persons injured

The Government of the Hong Kong Special Administrative Region CNS (2008)

CNS (2008)

XINHUANET (2008)

• Source• AD (2008b)• Beijing Review (2008) • CNS (2008)• NCE (2008)

• XINHUANET (2008)

Cologne North-South Metro Tram Line,

Germany, 3 March 2009

Wallis, S (2009)

• Background• Construction of a shaft using diaphragm walls

• The failure• Collapse of the diaphragm walls

• Possible causes of failure

• Possible causes of failure • ‘Boiling’ of the shaft’s invert under high pressures, loss of ground

due to inflow of groundwater, and creating a void outside the diaphragm walls into which the archive building collapsed

• Protective measures such as compensation grouting not carried out for protection of the buildings adjacent to the excavation

• Consequences• Collapse of the city’s historical archive building • Partial collapse of two apartment buildings• Evacuation of local residents (80 families in 10 buildings)• Two people killed

• Source

• Source• Wallis, S (2009)

Wallis, S (2009)

Brightwater Tunnel, Seattle, U. S. A.,

8 March 2009

Wallis, P (2009a)

• Background• Tunnelling by Mixshield slurry TBM

• The Failure• 4.5m x 9m sinkhole formed at a driveway of a house

• Possible cause of failure • The inexperience TBM operator with the closed slurry system

8 March 2009

• The inexperience TBM operator with the closed slurry system making it difficult to judge the amount of material being excavated during a shove

• The presence of a large boulder in the face that stalled penetration without slowing extraction of material and caused over excavation

• The high artesian water pressure and its influence on the excavation cycle

• Consequences• The driveway of a house damaged

• Emergency and remedial measures• Filling the sinkhole with crushed rock and sand

• Source

8 March 2009

• Source• Wallis, P (2009a)

Seattle’s Beacon Hill Light Rail, U. S. A.,

July 2009

Wallis, P (2009b)

• Background• Tunnelling by EPBM

• The failure• A 6.4m deep sinkhole formed at the ground surface• Six other large voids were found 6m to 18m below the ground

surface and behind the segmental lining of the bored TBM running tunnels

July 2009

tunnels

• Possible cause of failure • Over excavation when the EPBM hit pockets of sand in the stable

clay stratum

• Consequences• Sinkhole in the front yard of a house near its foundation

• Remedial measures• Filling the voids with 200 to 400 cubic yards of controlled density fill • Compaction grouting beneath the voids and the top of the running

July 2009

• Compaction grouting beneath the voids and the top of the running tunnels

• Source• Wallis, P (2009b)

Cairo Metro Tunnel, Egypt, 3 Sept. 2009

Wallis, S (2009a)

• Background• Tunnelling by 9.4m diameter Mixshield slurry TBM

• First failure• A segment fallen out of a ring subsequently forming a sinkhole on

the ground surface

• Second failure

• Second failure• Second ground collapse occurred after the pouring of concrete to

attempt to arrest the first collapse

• Possible cause of failure • First failure - a segment of the recently installed ring just leaving

the tail shield fell and allowed water and soil to flow to the tunnel, filling the interior of the TBM and the tunnel.

• Possible cause of failure • Second failure – More than 1,000 m3 of concrete was used to fill

the first sinkhole. The weight of the concrete acting on soft ground under a high groundwater table caused a second groundcollapse

• Consequences• TBM buried• A parked car slid into the 15m-20m diameter x 20m deep

sinkhole• Evacuation of local residents (80 families in 10 buildings)

• Remedial measures• First failure – Backfilled the sinkhole with concrete • Second failure – Injection of chemical grout, vertically and on

inclines, to strengthen the soil around the TBM and the tunnel to support the recovery excavation to uncover the TBM

• Source

• Source• Wallis, S (2009a)

Shenzhen Express Rail Link, China, 27 March

2011, 4 May 2011 and 10 May 2011

• Background• Tunnelling by TBM at about

22m to 26m below ground • Several ground failures

occurred in Xiameilin, Futian District (福田區上梅林)

OD (2011)

Shenzhen Express Rail Link, China, 27

March 2011, 4 May 2011 and 10 May 2011• First failure (World Journal (2011))

• A sinkhole of about 7m diameter and 10m deep was formed at a football pitch on 27 March 2011

• The sinkhole was full of muddy water and air bubbles

• Consequence• Evacuation of nearby residents

• Evacuation of nearby residents

• Possible cause of failure• Unexpected change in sub-surface

materials encountered, from slight decomposed rock to completely decomposed rock

• Remedial Measures• Backfill of the sinkhole with concrete

World Journal (2011)

2011, 4 May 2011 and 10 May 2011

• Second failure (21CN (2011))• A sinkhole of about 10m in diameter was formed near the

location of the first failure on 4 May 2011

• Possible cause of failure

• Heavy rainfall and the ground at the location of the previous failure had not been fully stabilized

• Third failure (TKP (2011))• A sinkhole of about 7m deep was formed at the ground surface

during the changing of cutter discs on 10 May 2011

• Possible cause of failure• Loose fill layers with high water infiltration • Existence of a sub-layer drainage channel

2011, 4 May 2011 and 10 May 2011• Fourth failure ((SD(2011))

• A sinkhole of about 1.5m in diameter and 7m deep formed atfootball pitch where previous three ground collapses occurredon 18 May 2011

SD (2011)

2011, 4 May 2011 and 10 May 2011

• Fifth failure (21CN (2011))• A sinkhole of about 5m deep in plan area of 100m2 was formed

on a road on 30 October 2011

• Possible causes of failure

• Existence of soft and hard lens of soil above the tunnel

• Leakage of compressed air

• Remedial Measures• Backfill of the sinkhole with soil

2011, 4 May 2011 and 10 May 2011

2home (2011)

2011, 4 May 2011 and 10 May 2011

• Source• 2home (2011)• 21CN (2011)• OD (2011)• SD (2011)• TKP (2011)

• TKP (2011)• World Journal (2011)

Hengqin Tunnel, Macau, 19 July 2012

MD (2012)

• Background• Four-lane 1.57km long road tunnel constructed by the cut-and-

cover method

• Failure• The lateral support wall collapsed resulting in caving of the

• The lateral support wall collapsed resulting in caving of the surrounding ground surface

• Possible cause of failure • Existence of a weak geological structure in the sub-surface • Rising of groundwater levels due to heavy rainfall causing the weak

soil between the interlayer to slip • Failure of the construction of support structures to keep pace with

the excavation

• Possible cause of failure • Weak ground with high groundwater levels increasing pressure

acting on the foundation pit pile

• Consequences

• Five heavy machines buried• Programme delayed

• Source• MD (2012)• MDT (2012) • OD (2012)

Hong Kong Cases

MTR Modified Initial System, Prince Edward

Station, Nathan Road, 12 Sept. 1977

• Background• A running tunnel (5m in diameter) being constructed from Prince

Edward Station by the drill and blast method• Ground above the tunnel strengthened

• The failure

• The failure• A wall section of the running tunnel under Nathan Road

collapsed• The subsidence did not affect the road surface

• Possible causes of failure• Gap existed between the ground treatment above the station

tunnel and that above the running tunnel allowing the soil to flow into the tunnel

Nathan RoadWater table

Station Tunnel RunningTunnel

Annular GroundTreatment

after Clay & Takas (1997)

• Consequences• Nathan Road between Argyle Street and Arran Street closed as

a safety measure• Three buildings (Nos. 745, 745A and 745B Nathan Road)

involving 100 people evacuated• Closure Order issued for nearby shops and a petrol station

• Source• Clay & Takacs (1997)• SCMP (1977)

MTR Island Line, 22 Hennessy Road, 1 Jan. 1983

• Background • Tunnelling from Admiralty to Causeway Bay for MTR Island Line

using the drill and blast method• Tunnel formed by the drill and blast method

• The failure

• The failure• Water-bearing fill flowed into the tunnel, opening a hole at the

road above• 1,500m3 of material flowed into the tunnel creating a void of an

area of 100m2 and 30m deep beneath the road surface

• Possible cause of failure• Misinterpretation of the geology by the Contractor• Blasting went too far, resulting in the tunnel penetrating the

rock into soft ground

Hennessy RoadWater

Soft Ground

after Clay & Takas (1997)

Shield Chamber

Water table

• Consequences• Cracks found in the granite masonry of the outside wall of a

building at 22 Hennessy Road• At least 21 timber piles beneath an adjacent building of 22

Hennessy Road exposed• More than 150 people in 18-22 Hennessy Road evacuated

• More than 150 people in 18-22 Hennessy Road evacuated• The building at 18-20 Hennessy Road reopened 3 hours after

the incident and the building at 22 Hennessy Road 6 days later

• Remedial measures• The void was backfilled by grout• The floor slab of the building at 22

Hennessy Road pushed up by the grouting works by 50-75mm

• Sources• Clay & Takacs (1997)• SCMP (1983)

SCMP (1983)

MTR Island Line, Shing On Street,

Shau Kei Wan, 23 July 1983

MP (1983a)

• Background • Tunnelling from Tai Koo Station to Sai Wan Ho Station for

MTR Island Line

• The failure

• 13m x 1m void formed

• Consequences• Section of Shau Kei Wan Road closed• Building at 122-124 Shau Kei Wan Road settled more than

100mm and tilting observed• More than 80 families (400 people) evacuated & a woman injured• Water main damaged due to the settlement

• Water main damaged due to the settlement• Water and gas supplies stopped

• Source• MP (1983a)

MTR Island Line, 140-168 Shau Kei Wan Road

16 Dec. 1983

MP (1983a)

16 Dec. 1983

• Background• Construction of Sai Wan Ho Station for MTR Island Line

• The failure• More than 40mm of ground settlement• About 150m3 of soil flowed into the tunnel leaving a void

• About 150m3 of soil flowed into the tunnel leaving a void between Shau Kei Wan Road and the tunnel

• Consequences• Section of Shau Kei Wan Road closed• Water supply stopped

• Source• MP (1983b)

16 Dec. 1983

• MP (1983b)

Kowloon Southern Link Contract KDB 200,

Canton Road, 21 Oct. 2006

GEO File Information

• Background• Twin railway tunnels between Jordan Road and East Tsim Sha

Tsui Station constructed by a slurry TBM• Incident of ground loss occurred at TBM launch area

• The failure• 3m(W) x 3.5m(L) x 3m(D) sinkhole formed reaching the ground

surface

• Possible cause of failure• Slurry leakage and loss of slurry support pressure

• Consequences • Crater formed at the ground surface closed to a busy road and a

gas main

• Remedial measures

• Remedial measures• Backfilling of the sinkhole with stockpile materials and sub-base

materials

• Source• GEO File Information

Salisbury Road, 3 June 2007

• Background• Twin railway tunnels between Jordan Road and East Tsim Sha

Tsui Station constructed by a slurry TBM

• The failure

• The failure• 2m x 3m sinkhole reaching the ground surface

• Possible cause of failure• Sudden air pressure loss through the interface between

CDG/HDG and overlying marine sand during a compressed air intervention, resulting in loss of face support and subsequent formation of sinkhole

• Consequences• Crater formed at the ground surface, with associated settlement• Temporary closure of a busy road lane• A low pressure gas main and a 1200 mm stormwater drain were

affected

• Remedial measures• Backfilling of sinkhole with granular fill

• Source• GEO File Information

References

2home (2011). <www.2home.com.cn/article/article_4190.html> (31 October 2011).

21cn (2011). <http://house.21cn.com/collect/2011/10/31/9615710.shtml> (31 October 2011).

AD (2008a). 珠江橋口塌半邊馬路. Apple Daily Newspaper. 19 January 2008, Hong Kong, pp A22.

AD (2008b). 杭州地鐵地盤塌陷增至2死19傷<http://www.appleactionews.com/site/art_main.php?&iss_id=20081116&sec_id=10793096&art_id=11853290&dis_type=ss&media_id=1>.

Beijing Review website (2008). Death Toll Could Reach 21 in Tunnel Collapse. <http://www.bjreview.com.cn/headline/txt/2008-11/19/content_165283.htm> (19 Nov 2008).

References

Boos, R., Braun, M., Hangen, P., Hoch, C., Popp, R., Reiner, H., Schmid, G., & Wannick, H. (2004). Underground Transportation Systems, Chances and Risks from the Re-insurer’s Point of View.Munich Re Group, Germany, pp 58-62. <http://www.munichre.com/> (31 Jan. 2007).

China Daily (2004). 100 homeless after metro site collapse. <http://www.chinadaily.com.cn/english/doc/2004-04/02/content_320246.htm> (2 April 2004).

04/02/content_320246.htm> (2 April 2004).

Civil Engineer International (1995). Tunnel lining removal prompts LA Metro cave in. Institution of Civil Engineers, July Issue, p10.

CNS (2008). <http://www.chinanews.com/>.

Clay, R.B. & Takacs, A.P. (1997). Anticipating the unexpected – Flood, fire overbreak, inrush, collapse. Proceedings of the International Conference on Tunnelling Under Difficult Ground and Rock Mass Conditions, Basel, Switzerland, pp 223-242.

Construction Today (1994a). Police probe repeat Munich tunnel breach. Construction Today, October Issue, pp 4-5.

Construction Today (1994b). Unstable ground triggers Munich tunnel collapse. Construction Today, October Issue, p 5.

Dubois, P. & Rat, M. (2003). Effondrement sur le chantier "Météor“. Conseil Général des Ponts et Chaussées, France, 22p. <http://www2.equipement.gouv.fr/actualites/Rapports/Meteor.pdf>

References

<http://www2.equipement.gouv.fr/actualites/Rapports/Meteor.pdf> (31 Jan. 2007).

European Foundations (2005). Tighter NATM rules follow Barcelona failure. European Foundations, Spring Issue, No. 26, p 3.

GEO File Information. GEO File Reference: GCME 3/5/7989/05, KSL Southern Link – C/No. KDB200, West Kln Station & Ancillary Bldg & Tunnel.

Golder (2005). Causes of Subsidence, 2 November 2005, Lane Cove Tunnel Project. Sydney NSW, 52p.

Government of Singapore (2005). Report of the Committee of Inquiry into the Incident at the MRT Circle Line Worksite That Led to the Collapse of Nicoll Highway on 20 April 2004. Government of Singapore, Land Transport Authority. <http://www.lta.gov.sg/home/index_home_nicoll.htm> (31 Jan.

References

<http://www.lta.gov.sg/home/index_home_nicoll.htm> (31 Jan. 2007).

Ground Engineering (1994). London NATM controversy. Ground Engineering, November Issue, p 6.

Ground Engineering (2000). Catalogue of disaster. Ground Engineering, August Issue, pp 10-11.

Ground Engineering (2005). Australian tunnel collapse raises doubts over NATM. Ground Engineering, December Issue, p 6.

Ground Engineering (2006a). Sydney tunnel collapse triggered by under-designed rock bolts. Ground Engineering, February Issue, p 4.

Ground Engineering (2006b). Rock bolts used instead of steel girders may have contributed to Lane Cove collapse. Ground Engineering, May Issue, p 4.

Gulp (2007). Desenvolvimento e diversão. <http://gulp.com.br/imagem/acidente-no-metro-de-sao-paulo> (17

References

<http://gulp.com.br/imagem/acidente-no-metro-de-sao-paulo> (17 January 2007).

HSE (1996). Safety of New Austrian Tunnelling Method (NATM) Tunnels. Health & Safety Executive, UK, 86p.

HSE (2000). The Collapse of NATM Tunnels at Heathrow Airport. Health & Safety Executive, UK, 116p.

ICE (1998a). Bulkhead location blamed for DLR blast. New Civil Engineer, Institution of Civil Engineers, February Issue, pp 3-4.

ICE (1998b). HSE signs up QC Carlisle for HEX prosecution. New Civil Engineer, Institution of Civil Engineers, March Issue, pp 4-5.

ICE (1999). Heathrow Express court cases kicks off. New Civil Engineer, Institution of Civil Engineers, January Issue, p 6.

ICE (2003). Ground failure linked to well collapses. New Civil Engineer, Institution of Civil Engineers, February Issue, pp 6-7.

ICE (2004). Docklands tunnel blowout down to “elementary error”, says

References

judge. New Civil Engineer, Institution of Civil Engineers, January Issue, pp 8-9.

ICE (2006). Australian tunnel collapse raises new NATM doubts. New Civil Engineer, Institution of Civil Engineers, January Issue, pp 6-7.

ICE (2008). Heart of darkness, New Civil Engineer, Institution of Civil Engineers, September Issue, pp 14-15.

IMIA. <http://www.imia.com>.

IMS. <http://www.imstunnel.com/index2.htm>.

Karlsrud Kjell (2010). Technical Note : Experience with tunnel failures in Norwegian tunnels. The Government of the Hong Kong Civil Engineering and Development Department. (Unpublished).

Kavvadas, M., Hewison, L.R., Laskaratos, P.G., Seferoglou, C. & Michalis, I. (1996). Experiences from the construction of the Athens Metro. Proceedings of International Symposium on the

References

Metro. Proceedings of International Symposium on the Geotechnical Aspects of Underground Construction in Soft Ground, City University, London, April.

Lee, I. M. & Cho, G. C. (2008). Underground construction in decomposed residual soils (presentation slides). The 6th

International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground (IS-Shanghai 2008), Tongji University, Shanghai, April.

Lee, W. F. & Ishihara, K. (2011) Forensic diagnosis of a shield tunnel failure. Engineering Structures. Volume 32, Issue 7, July 2010, Pages 1830-1837.

Longhoo (2004). 廣州地鐵3號線工地塌方﹐附近居民樓傾斜.<http://www.longhoo.net/big5/longhoo/news/civil/node107/userobject1ai172577.html> (2 April 2004).

Madrid (1996). Informe sobre el NATM del Health & Safety Executive,

References

Madrid (1996). Informe sobre el NATM del Health & Safety Executive, de Inglaterra, 1996. <http://www.madrid.org/metro/infonatm.html> (1996).

McFeat-Smith, I. M. (2008). Personal communications. GEO File Reference: GCME 6/8/6-1, Newspaper Articles for Tunnels/Media Reports.

MD (2012). 橫琴澳大塌河隧. Macao Daily, 21 July 2012, Macau.

MDT (2012). Report : four causes account for Hengqin tunnel collapsed. Macau Daily Times. 14 August, 2012.

Mihalis, I. & Kavvadas, M. (1999). Ground movements caused by TBM tunnelling in the Athens Metro Project. Proceedings of International Symposium on the Geotechnical Aspects of Underground Construction in Soft Ground, Japan, July, pp 229-234.

MP (1983a). 筲箕灣路陷傳真. Ming Pao Newspaper. 24 July 1983,

References

MP (1983a). 筲箕灣路陷傳真. Ming Pao Newspaper. 24 July 1983, Hong Kong.

MP (1983b). 西灣河站塌泥墜道情況已穩定. Ｍing Pao Newspaper. 17 Dec. 1983, Hong Kong.

NNN (2005). National Nine News. 2 Nov. 2005, Australia.

OD (2011). 深圳屋苑地陷居民逃命. Oriental Daily, 29 March, 2011, Hong Kong.

OD (2005). 高捷洞陷. Oriental Daily. 7 Dec. 2005, Hong Kong.

OD (2012). 橫琴澳大新校區隧道坍塌. Oriental Daily, 21 July, 2012, Hong Kong.

Property Highlights of Singapore (2008). <http://propertyhighlights.blogspot.com/2008/05/circle-line-work-causes-cave-in-off.html> (25 May 2008).

References

SCMP (1977). MTR tunnel collapses. South China Morning Post. 13 Sept. 1977, Hong Kong.

SCMP (1983). MTR tunnelling may be to blame. South China Morning Post. 2 Jan. 1983, Hong Kong.

SD (2011). Fourth land collapse in Xiameilin. Shenzhen Daily, 20 May 2011, Shenzhen.

Shin, J.H., Lee, I.K., Lee, Y.H. & Shin, H.S. (2006). Lessons from serial tunnel collapses during construction of the Seoul subway Line 5. Tunnel and Underground Space Techonology, Issue no. 21, pp 296-297.

Sina (2008a). <http://news.sina.com/ch/phoenixtv/102-101-101-102/2008-01-17/15232606535.html> (17 Jan 2008).

Sina (2008b). <http://news.sina.com.hk/cgi-

References

Sina (2008b). <http://news.sina.com.hk/cgi-bin/nw/show.cgi/9/1/1/613096/> (18 Jan 2008).

Siow, M. T. (2006). Geotechnical aspects of the SMART tunnel. International Conference and Exhibition on Trenchless Technology and Tunnelling, 7-9 March 2006, Malaysia.

SMH (2005). The Sydney Morning Herald. 2 Nov. 2005, Australia.

Soufun (2004).追踪报道::::广州地铁3333号线工地塌方险情受控. <http://news.gz.soufun.com/2004-04-04/259585.htm> (4 April 2004).

SP (2005). Sing Pao Newspaper. 6 Dec. 2005, Hong Kong.

ST (2005). Sing Tao Newspaper. 6 Dec. 2005, Hong Kong.

Sun (2005). Sun Newspaper. 6 Dec. 2005, Hong Kong.

TANEEB (2005). Hsuehshan Tunnel. Taiwan Area National Expressway Engineering Bureau (台灣國工局), Taiwan. <http://egip.taneeb.gov.tw> (31 Jan. 2007).

Taiwan Info (2004). Nouvel incident sur le chantier du métro de

References

Taiwan Info (2004). Nouvel incident sur le chantier du métro de Kaohsiung. Taiwan. <http://taiwaninfo.nat.gov.tw/Societe/1092119498.html> (31 Jan. 2007).

Takahashi, Hiroshi (2010). Huge collapse leading to ground surface caving in 130m earth thickness.

TT (2005). Cave-in at KRTC site snarls up Kaohsiung traffic. Taipei Times. 5 Dec. 2005, Taiwan.

TKP (2005). Ta Kung Pao Newspaper. 7 Dec. 2005, Hong Kong.

TKP (2011). 深圳一小區三次地陷居民撤離. Ta Kung Pao Newspaper, 11 May 2011, Shenzhen .

TVB News (2005). TVB News. 4 Dec. 2005, Taiwan.

Tunnels & Tunnelling (2005). Lausanne Metro Tunnel collapse. Tunnels & Tunnelling International, April Issue, p 6.

References

Tunnels & Tunnelling International, April Issue, p 6.

Wallis, P. (2009). EPBM recovery reveals the unexpected. TunnelTalk. <http://www.tunneltalk.com/YorkSewer-Aug-09-TBM-recovery-reveals-the-unexpected.php> (August 2009).

Wallis, P. (2009a). Sinkhole bothers Brightwater. TunnelTalk. <http://www.tunneltalk.com/Brightwater-Mar09-Brightwater-sinkhole.php> (March 2009).

References

Wallis, P. (2009b). Beacon Hill celebration and investigation. TunnelTalk.<http://www.tunneltalk.com/BeaconHill-Jul09-Celebration-and-Investigation.php> (July 2009).

Wallis, S. (2008). Buried EPBM recovery in Toronto. TunnelTalk<http://www.tunneltalk.com/Buried-EPBM-recovery-in-Toronto.php>(August 2008).

Wallis, S. (2009). Köln - speculation and anger in aftermath. TunnelTalk.<http://tunneltalk.com/Cologne-collapse-Mar09-Deadly-collapse-in-Cologne.php> (March 2009).

Wallis, S. (2009a). Cairo Metro tunnel collapse. TunnelTalk. http://www.tunneltalk.com/Cairo-Metro-Sep09-tunnel-collapse.php>(September 2009).

References

World Journal (2011). 高鐵惹禍？深圳地陷驚現10米深坑<http://www.worldjournal.com/view/full_news/12536326/article-

%E9%AB%98%E9%90%B5%E6%83%B9%E7%A6%8D%EF%BC%9F-%E6%B7%B1%E5%9C%B3%E5%9C%B0%E9%99%B7-%E9%A9%9A%E7%8F%BE10%E7%B1%B3%E6%B7%B1%E5%9D%91?instance=news_pics> (29 March 2011).

WWP (2005). Wen Wei Po Newspaper. 6 Dec. 2005, Hong Kong.

XINHUANET. <http://www.xinhuanet.com/> (4 April 2004).

General References

Brand, E.W. (1996c). Bibliography on Settlements Caused by Tunnelling to March 1996 (GEO Report No. 51). Geotechnical Engineering Office, Hong Kong, 70 p.

Health and Safety Executive (HSE) 1996. Safety of New Austrian Tunnelling Method (NATM) Tunnels, A review of sprayed concrete tunnels with particular reference to London Clay, (HSE) Books, Sudbury, 80 p.

Sudbury, 80 p.

Jacobs J. D. (1975). Some tunnel failures and what they have taught. Hazards in Tunnelling and on Falsework, Institution of Civil Engineers, London, pp 37-46.

Moh, Z.C. & Hwang, R.N. (2007). Lessons learned from recent MRT construction failures in Asia Pacific. Journal of the Southeast Asian Geotechnical Society, December 2009, pp 121-137.

cases already included in the catalogue?

General References

Seidenfub, T. (2006). Masters Degree in Foundation Engineering and Tunnelling: Collapse in Tunnelling. Stuttgart University of Applied Sciences, Germany, 194 p. (Note: 109 numbers of failures of all types of tunnels). <http://www.ita-aites.org/cms/fileadmin/filemounts/general/pdf/ItaAssociation/ProductAndPublication/Thesis/ThesisSeidenfuss.pdf>some the failure cases already included in the catalogue?

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