Developed countries require a modern infrastructure Roads Railways Power Communications Water Wastewater

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1 Introduction to Soft Ground Tunnelling in Urban Environment Dr. Noppadol Phienwej Geotechnical and Geo-environmental environmental Engineering School of Engineering and Technology Asian Institute of Technology

2 ITA- Why Tunnel? A country s infrastructure is one of its main assets Developed countries require a modern infrastructure Roads Railways Power Communications Water Wastewater Gas Congestion above and at surface level in urban metropolis, where space is at a premium, means going under the ground is the only viable option

3 Infrastructures in Modern Urban Area

4 Underground Space Utilization in Urban Business Area For Better Environment

5 Characteristics and Constraints of Urban Tunnelling Tunnelling at shallow depth Mostly soft ground tunnelling High risk due to soft ground and groundwater Construction in congestion area Traffic disturbance Tunnelling at close proximity to existing buildings and utilities- space constraints Need to minimize damages to existing structures and third parties Need to control minimize movements Many parties involving- Work coordination

6 TUNNEL GROUNDS ROCK TUNNEL SOFT GROUND TUNNEL

7 Rock Tunnelling

8 Rock Tunnelling

9 Rock Tunnelling Investigation, Design & Construction W Geotechnical Longitudinal Section E 0 G+ G F E D C B A ,40-0,30-0,20-0,10 0, Station [m] Egnatia Motorway, Anilio Tunnel (Greece)

10 Rock Tunnel Excavation Drill & Blast

11 Rock Tunnel Boring Machine

12 Rock Tunnel Boring Machine

13 Soft Ground Tunnelling

14 Soft Ground Tunnelling What is soft ground? Soft ground consists of various mixtures of sand, silt and clay. It can be described as firm, raveling, squeezing, running flowing or swelling. In all types of tunnelling, face stability is the primary goal, this is followed by ground movement control.

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16 Ground Movement Soft Ground Tunnelling Face Stability

17 Tunnel Collapse

18 M4 metroline crossing Huangpu River in Shanghai

19 Methods of Tunnel Construction in Soft Ground Cut & Cover Construction Tunnelling Shield Tunnelling Non-Shield Tunnelling Shotcrete & steel arch Pipe Jacking (Micro Tunnelling)

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21 Methods of Tunnel Construction ti in Soft Ground

22 Cut and Cover for MRT Singapore Hong Kong

23 Stuttgart, Germany

24 CUT AND COVER TUNNEL DIAPHRAGM WALL

25 BANGKOK MRT PILE SUPPORTED STRUCTURE

26 SHIELD TUNNELING

27 Shield Tunnelling

28 Shield Tunnelling

29 Reinforced Concrete Segmental Lining

30 RC Segmental Rings

31 Pipe Jacking (Micro Tunnelling)

32 Thrust Shaft S I T E L A Y O U T E Control Container TBM Lubricant Preparation Plant Entrance Ring (Soft Eye) Jacking Pipe Jacking Frame Thrust Wall Base Slab

33 P I P E J A C K I N G TBM and first pipe placed on jacking frame and ready to commence excavation through the soft eye

34 P I P E J A C K I N G TBM commences excavation and both, pipe and machine together are pushed through the soft eye into the ground by the jacking cylinders

35 P I P E J A C K I N G Excavation is stopped, jacking pp, j g cylinders are moved backward so that the next pipe can be placed behind the string

36 P I P E J A C K I N G Then the jacking cylinders are again pressed dtightly against the pipe end, ready to push the whole line forward

37 P I P E J A C K I N G

38 P I P E J A C K I N G

39 P I P E J A C K I N G

40 P I P E J A C K I N G

41 P I P E J A C K I N G Jacking Operation - EPB 1500, 2600 and AVN 1200

42 Shields for Pipe Jacking

43 World Record Breaking Pipe Jacking Works in Bangkok

44 Shield Tunnelling

45 Shield Types

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50 Slurry Shield

51 EPB Shield

52 General arrangement EPB Shield Machine

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55 Non-Shield Tunnelling Conventional Method

56 Non-Shield Tunnelling Shotcrete + Steel lattice Soil Improvement NATM

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59 FIRST ROAD TUNNEL BETONG, YALA

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62 TUNNEL WITH SHOTCRETE AND STEEL ARCH

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64 Invert Shotcreting

65 SEQUENTIAL EXCAVATION

66 SEQUENTIAL EXCAVATION

67 UNSTABLE GROUND

68 ROOF SPILING FOREPOLING

69 When there are stability problem of ground Umbrella Roof Method

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72 PIPE JACKED ROOF

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77 Freezing method was used to remove the old structure and build new structure Freezing pipes needed to freeze the ground under the pre- existing tunnel. It could not be installed from the road. Therefore, the curve boring method was adopted. New structure Old structure Extent of frozen ground

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84 INTERVENTION SHAFT EXCAVATION Soft Clay Stiff Clay Sand

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90 TUNNEL PORTALS AND SHAFTS

91 TUNNEL PORTAL Slope Stability

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93 Permanent Shaft Sinking

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95 Completed Shaft from tunnel level

96 Irregular Shape Shaft

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99 TUNNEL SUPPORT

100 Cross section showing primary and secondary Cross section showing primary and secondary lining, after Hughes (1987)

101 DESIGN PRINCIPLES PRIMARY LINING OF SHOTCRETE INSTALLED CLOSE BEHIND FACE AS EXCAVATION PROCEEDS TO MINIMISE GROUND RELAXATION thin shell design approach ( limited moment capacity) applied loads less than full overburden due to negative pore pressure leading to arching support time dependent build up of loads allow for stress concentrations from nearby tunnels limited duration of use before secondary lining cast includes load factor of 1.4 structural analysis using bedded beam model

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103 Installed Segmented Rings Behind Shield Tail Skin

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105 Segmental Lining

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107 Primary Grouting After Segment Erection Cement / Bentonite Sodium Silicate Grouting Material gels within 8 Sec.

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110 Ring Deformation+Pressure

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112 OBSTRUCTION

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114 Difficulties in Tunnelling and Effects on Building Foundation

115 BUILDING PROTECTION PRINCIPLES DESIGN & CONSTRUCTION METHODS TO MINIMISE GROUND MOVEMENTS PREDICTION OF MOVEMENTS REQUIRED BUILDING CONDITION SURVEY 2nd & 3rd STAGE ASSESSMENT IF REQUIRED ALERT LEVELS IDENTIFIED BEFOREHAND BUILDING PROTECTION IF REQUIRED INSTRUMENTATION & MONITORING

116 BUILDING DAMAGE

117 Building response to ground movement

118 6.3 m outer-diameter Single Track

119 TUNNEL PILE RELATIVE POSITION SUMMARY Existing superstructure Angel Underground Station, London MRT North-East Line C704, Singapore MTR Island Line, Hong Kong MRTA Subway, Bangkok Electric Power Tunnel, Japan Tunnel Type 1 45 o Type 4 Type 2 Type 3 MRT Circle Line C825, Singapore Cable Tunnel, London Tokyo Subway Line 7, Japan Jubilee Line Extension, London Channel Tunnel Rail Link 2, London MRT Circle Line C825, Singapore North/South Metroline, Amsterdam

120 TUNNELLING NEAR TO PILE FOUNDATION Columns Building Negative skin friction (NSF) Downdrag Tunnelling in progress NSF Soil movement Pile cap Resisting force Lateral deflection Piles

121 Transverse Settlement Trough due to Tunnel Boring Location:Settlement Array, CS-9A (SS-9-1A-T ) Underground South Structures : Petchaburi Station to Rama IX Station F I 9-1-J L T t, mm Settlement Instrumentation or Reading Error Peck NB i-factor = 9.22 m SB i-factor = 9.62 m Vs = 2% 1st NB 2nd SB Distance, m -8m(NB) 0m(NB) +8m(NB) +38m(NB) +79m(NB)/0m(SB) (SB) +90m(NB)/+30m(SB) (SB) +122m(NB)/+67m(SB) (SB) +172m(NB)/+125m(SB) 125 (SB) +688m(NB)/+430m(SB) +715m(NB/SB) Peck's Figure 5.18: Transverse Settlement Trough due to Tunnel Boring (Parallel Running)

122 Vertical Movement Contour for Twin Tunnels (Case 3) Loganathan and Poulos (1998) s method

123 E=5,000 knlm^2 E=4,300 knlm^2 E=5,000 knlm^2 E=4,300 knlm^2 E=68,170 knlm^2 E=400,000 knlm^2 Plastic Point Yield Point

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125 RESPONSE OF PILE FOUNDATION TO TUNNELLING Pile lateral deflection and bending moment Transversely (Perpendicular to tunnel advancing direction) Longitudinally (Parallel to tunnel advancing direction) Tensile force in pile Possible near pile head depending on the type of restraint Dragload (additional axial force) in pile Above tunnel springline or invert level Pile settlement Due to downdrag The type of response depends on the tunnel-pile relative position

126 Bangkok Tunnelling Experiences

127 RISK IN TUNNEL CONSTRUCTION

128 Causes of Soft Ground Tunnel Collapses

129 RISK IN TUNNEL CONSTRUCTION Considerably High Inherent Uncertainty in Geological Condition (Variability in Ground Type & Groundwater) Potential of Large-scale accidents D t Thi d P t (U b Damages to Third Party (Urban tunnelling)

130 Thank You