Effects of tunnel construction on nearby pile foundations c

Table 2.1 Summary of reported case histories Reference Jacobsz et al. (2005) Takahashi et al. (2004) Development / CTRL 2, London Rinkai Line, Tokyo New London Bridge (2002) House, London (2000) Tunnel Type Project Selemetas et al. Coutts & Wang Soil Type MRT North-East Line C704, Singapore LC EPB shield tunnel Very dense Slurry shield sand tunnel LC Weathered Granite Pile Type Driven pile & bored pile N/A In-pile Xpile / Lp / Xpile Htun Dtun Dpile Lp VL monitoring Dtun Htun (m) (m) (m) (m) (m) (%) No N/A < 1.0 Varied 8.15 Varied Varied No N/A 0.51 33.2 7.1 0.6 17 0.5 No 1.23 0.91 10.7 22 8.7 1.4 20 N/A 0.85 > 1.0 5.3 6.2 1.2 N/A N/A 5.2 14 6.3 0.45 15 0.4 30 8.7 N/A 20 N/A 26 7.9 2.0 41 to 1.0 to 64 1.4 15 7.35 0.25 N/A Sprayed concrete Bored pile lining tunnel (under-reamed) EPB shield tunnel Bored pile EPB shield tunnel Bored RC pile No 0.83 1.07 Bored pile No N/A 0.67 Yes Above tunnel Above tunnel 16 to 20 0.28 to 1.0 Tham & MRT North-East Deutscher Line C705, (2000) Singapore Powderham et Jubilee Line al. (1999) Extension, London Forth & Thorley MTR Island Line, Weathered Compressed air (1996) Hong Kong Granite shield tunnel Ikeda et al. Underground (1996) Railway, Japan Soft clay EPB shield tunnel Timber pile No N/A 0.33 Moroto et al. Electric power Very soft silty (1995) tunnel, Japan clay EPB shield tunnel N/A No > 2.18 2.23 > 8.5 18.8 3.9 N/A 42 N/A Mair (1993), Angel Underground Lee et al. (1994) Station, London Yes 0.69 > 1.0 5.75 Varied 8.25 1.2 28 2.0 Nakajima et al. 1.2 Varied N/A N/A N/A N/A Old Alluvium LC Sprayed concrete lining tunnel LC Hand-dug tunnel Nanboku Line, Alluvial and Slurry shield (1992) Tokyo Diluvial tunnel Inose et al. Nanboku Line, Soft silt & Slurry shield (1992) Tokyo sandy gravel tunnel N/A = Not reported, LC = London Clay Above tunnel 1.58 Bored pile No 1.01 to 8.0 2.46 Bored pile (under-reamed) Bored pile No Bored pile No 0.74 & 0.66 N/A N/A N/A Above tunnel 4.9 & 6.5 Above tunnel N/A N/A 6.6 & 9.8 10 164 Table 2.2 Summary of reported centrifuge tests (in prototype unit) Reference Soil Type In-pile measurement Xpile / Dtun Pile head Lee & Chiang Dense settlement, pile (2004) saturated sand axial force & pile (2003) Soft clay Pile axial force & bending moment (1994), and Hergarden et al. (1996) 0.96 27.0 Up to No Yes No influence 9, 15, 4.98 21 & 27 1.6 9.00 16 6.0 1.26 25.0 N/A No No No 21.45 4.5 0.9 Up to 20 Yes & No Yes No Yes 2x2 Yes No & 4.77 Schrier 6.0 Pile group 1.50 axial force Bezuijen & 1.3 & Preloading zone of No 3.10, 3.93 bending moment (%) No settlement & axial force & pile (m) No sand Test (m) 28.2 1.43, 2.27, Test (m) 23.5 Pile head (1999) (m) 1.26 Dense dry settlement, pile (m) * Within 6.0 bending moment Test VL 15 sand Loganathan Lp 6.00 (2002) Pile head Dpile 1.6 Pile axial force & Stiff clay Dtun 1.00 Dense dry (2002) Htun 1.0 Feng et al. Jacobsz et al. xpile 3.0, 1.8, 0.83 bending moment Ran et al. Lp / Htun 0.92 0.7 & 0.9 6.45, 10.20, 13.95, 17.70 & 21.45 1.2, 1.0 & 0.9 15.0 & 18.75 15 5.50 18 No 6.0 0.8 18.0 Up to 10 21 No Yes Clay overlying dense sand Test Test Test Settlement and axial force at pile head 0.70, 0.93, 1.39 & 1.84 4.90, 6.50, 1.0 9.70 & 18.0 0.8 12.90 23.0 1.2 7.0 0.4 18.0 Up to 10 Yes & No 14.5 * Zone of influence – defined as the zone within 45o from tunnel springline 165 Table 2.3 Summary of reported prediction and design methods Method Descriptions Soil model Advantages / disadvantages Pertinent findings Reference 1) Pile response cannot be computed and unknown. Only Risk of damage to a piled building was assessed using method by Mair et al. (1996). The method categorises the damage according to the tensile overall building damage can be - assessed. Tham & - 2) The method was derived for strain computed at the building. Deutscher (2000) building supported on shallow foundation. 1) Simple & less time consuming. Empirical method for calculating greenfield soil 2) Can be used for pile with its movement was translated into pile settlement and pile stresses according to some assumptions - made through observations in centrifuge tests Empirical base within zone of influence. 3) Only pile axial response particularly settlement can be and field study. At small volume loss, end bearing pile settles equally to greenfield settlement at Jacobsz et pile base. Friction pile settles equally to al. (2005) Greenfield surface settlement. assessed. 1) Bearing capacity was checked via the comparison of pile base moment with resistance 1) Simple hand calculation. moment due to face pressure from shield 2) Only pile bearing capacity can machine. - be assessed. Nakajima - 3) Can be used for pile with its 2) Bearing capacity was checked via the et al. (1992) base above tunnel. comparison of reaction force at pile base with grouting or face pressure in tail void. Bearing capacity of pile during the shield advancement was investigated through assumption of an imaginative cone around pile base and compared to the face pressure from shield machine. 1) Simple hand calculation to determine the need for - mitigation work at pile base. 2) Can be used for pile with its - Inose et al. (1992) base above tunnel. 166 Table 2.3 Summary of reported prediction and design methods (continue) Method Descriptions Soil model FE analysis was used to compute pile settlement. A row of piles was modelled as a 2-D finite element sheet pile wall with reduced properties. 1) Less time consuming. Mohr-Coulomb (Drained) FE analysis was used to predict the piles reduction method adopted is 1) Less time consuming. lateral deflections at Angel Underground Linear elastic Development. Piles were not modelled and (Undrained) 2) Pile stiffness was not considered. assumed to deform with soil. 3) Soil model used is too simple. A 3-D model to simulate shield tunnel 1) More time consuming pile group. Pile-soil-tunnel interaction was taken into account. No physical data was Mohr Coulomb (Drained) back-analysed to verify the model’s reliability. element 2) Accuracy of pile properties unknown. advancement on adjacent single pile and 2x2 3-D finite Advantages / disadvantages A 3-D model to simulate open face tunnel advancement on adjacent single compared to 2-D analysis. Pertinent findings Reference Pile settlement followed the settlement of Vermeer & bearing layer where the pile base was Bonnier founded (1991) Pile lateral deflection was well predicted and provided an upper bound value compared to measured data. Significant axial force and deflection were induced lateral pile Mroueh & Shahrour study of pile axial and bending tunnel invert. Positive pile group effect (2002) responses. was observed. 1) More time consuming. FOS in pile was reduced significantly pile. Drucker-Prager 2) Unified approach. from 3.0 to 1.5. Centrifuge test results from Loganathan (Consolidation) 3) The simulation not represent were not significant. Transverse BM was (1999) was compared. A 3-D model to simulate plane strain tunnel adjacent to single pile. Parametric studies were carried out. The data from MRT NEL C704 was also briefly back-analysed. any type of tunnelling system. Non-linear elastic (Undrained) (1994) particularly when the pile base was below 2) Unified approach towards the in Lee et al. 1) Tunnel advancement was not simulated. 2) Unified approach. Axial force and BM Lee & Ng (2005) three times longitudinal BM. BM in pile is negligible when Xpile/Dtun>2. Cracking moment exceeded Cheng et when Xpile/Dtun Htun+R, BM in triple curvature. (2004) [R = pile radius] Single pile analysis can be used to Kitiyodom et represent piles in a group for BM, al. (2004), lateral deflection and settlement only. Matsumoto et Hence, no pile group effect. induced BM, al. (2005) 1) Only hand calculation required. Tunnelling lateral Chen et al. 2) Allow only single pile analysis. deflection, settlement and axial forces (1999), Chen 2) Limited to some assumptions. can be computed. et al. (2000) 168 Table 3.1 Weathering classification for Granite in Singapore (Dames and Moore, 1983) Grade Equivalent BS General description weathering grade G1 I and II Fresh to slightly weathered Granite G2 III and IV Moderately to highly weathered Granite G3 - G4 V and VI Bouldery soil : Boulders of Granite of variable weathering within completely weathered rock or residual soil Completely weathered Granite or residual soil Table 3.2 Details of instrumented pile foundation for bridge viaducts Pier No. Pile Pile Tunnel Pile length to XSB XNB XSB XNB no. of diameter length, depth, tunnel depth (m) (m) /Dtun /Dtun pile , Dpile Lp H tun ratio, Lp/Htun (m) (m.b.g.l.) (m.b.g.l.) 11 1.2 61.4 28.5 2.15 7.79 8.13 1.20 1.25 14 1.2 59.8 26.0 2.30 7.12 8.14 1.10 1.25 20 1.2 61.8 21.0 2.94 5.44 7.11 0.84 1.09 32 1.2 35.9 16.6 2.17 5.88 8.22 0.90 1.26 37 1.8 30.8 22.7 1.35 7.60 7.45 1.17 1.15 38 1.8 29.8 23.3 1.28 7.30 4.30 1.12 1.12 XSB = Distance between South bound tunnel axis and the nearest pile centre XNB = Distance between North bound tunnel axis and the nearest pile centre 169 Table 3.3 Construction stages of viaduct bridge and tunnels advancement Day (Reference) Year / Month Activities -151 -121 -90 -59 -31 30 61 91 122 153 183 214 244 275 306 335 366 396 427 457 1998 1999 2000 Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Pier 11 Piling work Pile cap construction Plinth casting Entire stem pour Flare head casting Casting of diaphragm Starting stub casting Casting of box girder web and bottom slab - Span P10/P11 Casting of deck slab - Span P10/P11 Casting of box girder web and bottom slab - Span P11/P12 Casting of deck slab - Span P11/P12 Casting of inner console slab - P9-P11 SB tunnel at Pier 11 NB tunnel at Pier 11 VWSG reading taken Pier 14 Piling work Pile cap construction Plinth casting Entire stem pour Flare head casting Casting of diaphragm Starting stub casting Casting of box girder web and bottom slab - Span P13/P14 Casting of deck slab - Span P13/P14 Casting of box girder web and bottom slab - Span P14/P15 Casting of deck slab - Span P14/P15 Casting of inner console slab - P13-P15 SB tunnel at Pier 14 NB tunnel at Pier 14 VWSG reading taken Pier 20 Piling work Pile cap construction Plinth casting Entire stem pour Flare head casting Diaphragm casting Starting stub casting Casting of box girder web and bottom slab - Span P19/P20 Casting of deck slab - Span P19/P20 Casting of box girder web and bottom slab - Span P20/P21 Casting of deck slab - Span P20/P21 Casting of inner console slab - P19-P21 SB tunnel at Pier 20 NB tunnel at Pier 20 VWSG reading taken Day (Reference) Year / Month Activities Apr 30 61 91 122 153 183 214 244 275 306 335 366 396 427 457 488 519 549 580 610 1999 2000 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec May Jun Jul Pier 32 Piling work Pile cap construction Plinth casting Entire stem pour SB tunnel at Pier 32 NB tunnel at Pier 32 VWSG reading taken Pier 37 Piling work Pile cap construction Plinth casting Entire stem pour SB tunnel at Pier 37 NB tunnel at Pier 37 VWSG reading taken Pier 38 Piling work Pile cap construction Plinth casting Entire stem pour SB tunnel at Pier 38 NB tunnel at Pier 38 VWSG reading taken LEGEND : DAY (REFERENCE) YEAR MONTH 275 2000 Jan Day 275 = no. of days from January 2000 compared to April 1999 (Day = April 1999 = Start of tunnelling work) 170 Table 3.4 Volume loss for SB and NB tunnels advancement Volume loss, VL (%) Pier no. SB tunnel NB tunnel 11 0.76 1.23 14 1.45 1.43 20 1.38 1.67 32 0.35 0.32 37 0.34 0.71 38 1.17 0.88 Table 3.5 Maximum dragload measured in piles due to tunnel advancement Due to southbound Due to southbound + Tunnel northbound tunnels Pier (Pile) kN % kN % 11 (P5) -2241 19 -6489 54 11 (P6) -2269 19 -7883 66 14 (P3) -5098 42 -7593 63 14 (P4) -2700 23 -6761 56 20 (P1) -3411 28 -5272 44 20 (P2) -2633 22 -6101 51 32 (P7) -1540 13 -1976 16 32 (P8) -1014 -2193 18 37 (P9) -2171 -3219 11 37 (P10) -2692 10 -4375 16 38 (P11) -4547 16 -5686 20 38 (P12) -2344 -3178 11 Note: % of the structural capacity -ve : compressive force (dragload) 171 Table 3.6 Maximum transverse bending moment measured in piles due to tunnels advancement SB SB + NB kNm kNm 11 (P5) 84 148 11 (P6) 14 (P3) 14 (P4) 20 (P1) 20 (P2) 142 464 219 401 163 569 267 227 395 253 32 (P7) 167 142 32 (P8) 37 (P9) 41 1040 95 1293 37 (P10) 577 841 38 (P11) 38 (P12) 1008 392 1163 798 Pier (Pile) Table 3.7 Maximum longitudinal bending moment measured in piles due to tunnels advancement SB SB + NB kNm kNm 11 (P5) 158 408 11 (P6) 14 (P3) 14 (P4) 20 (P1) 20 (P2) 32 (P7) 32 (P8) 37 (P9) 37 (P10) 38 (P11) 38 (P12) 51 30 87 131 49 97 33 536 555 991 304 452 43 166 129 180 50 66 710 648 1151 915 Pier (Pile) 172 Table 3.8 Comparison of the assumptions made in the design charts with C704 problem Pile configuration Pile head condition Design chart (Chen & et al., 1999) Single pile Free pile head Pile loading condition No load (Stress free) Limiting skin friction, fs Limiting end bearing pressure, fb Limiting lateral pile-soil pressure Pile stiffness, Epile Soil model Soil Young’s modulus, Esoil Tunnel diameter, Dtun Tunnel depth, Htun 48kPa 540kPa 30MPa Linear elastic 400Cu 6m 20m Construction time Undrained analysis Details MRT NEL C704 problem Pile group Pilecap exists (Pier 20 & 38) / No pilecap (Pier 14) No load (Pier 14, 20, 38) or partially loaded (i.e. Pier 11) 40 to 200kPa 540kPa 28MPa 30 to 300Cu 6.5m 26m (Pier 14) 21m (Pier 20) 23.3m (Pier 38) Time dependent problem 173 Table 4.1 Consideration of various physical factors in 3-D finite element modelling of shield tunnel Simulation considerations in numerical model Author Plaxis (2004) Software Lining element Back-up loading Grout element Grout pressure Shield element Overcut Shield jacking Disturbed face element Face pressure PLAXIS3D Lim (2003) CRISP3D Mroueh & Shahrour (2002) PECPLAS Lin et al. (2002) FLAC3D Melis et al. (2002) FLAC3D Augarde & Burd (2001) OXFEM Sousa et al. (2001) FLAC3D Guedes et al. (2000) ABAQUS Dias et al. (2000) FLAC3D Komiya et al. (1999) Unknown Swoboda & Krisha (1999) FINAL Lee & Rowe (1991) FEM3D Maranha & Neve (2000) FLAC3D Not considered in analysis Considered in analysis 174 Table 4.2 Soil parameters adopted for Mohr-Coulomb model Soil layer Eu (MPa) E' (MPa) φ' (o) c’ (kPa) G4a 10 8.7 28 20 G4b 43.3 40.0 30 30 G4c 75 65.0 30 30 G4d 150 86.7 30 30 G4e 200 86.7 30 30 Note: Please see section 4.3.3 for definition of soil layering Table 4.3 Critical state parameters adopted for MCC and SDMCC models Soil layer κ λ Γ M G4a 0.018 0.113 1.8 1.113 G4b 0.023 0.104 1.9 1.200 G4c 0.007 0.070 2.0 1.200 G4d 0.007 0.070 2.0 1.200 G4e 0.007 0.070 2.0 1.200 Note: Please see section 4.3.3 for definition of soil layering Table 4.4 Parameters for shear modulus in SDMCC model Soil Granite residual soil (Ng et al., 1998; Ng et al., 2000) Granite residual soil (Anand et al., 2001) A n1 m1 B n2 m2 b2 4500 0.7 0.2 0.71 1.0 0.2 -0.62 11500 0.7 0.2 2.0 1.0 0.2 -0.62 Table 4.5 Parameters for bulk modulus in SDMCC model C n3 m3 D n4 m4 b4 800 1.0 0.2 1.2 1.0 0.2 -0.61 175 Table 4.6 Summary of EPBM advance rate Average progress rate (m/day) Tunnel drive Serangoon to Woodleigh Serangoon to Kovan SB NB SB NB 3.9 8.25 10.65 Maximum progress rate (m/day) 18 21 176 [...]...Table 4.1 Consideration of various physical factors in 3-D finite element modelling of shield tunnel Simulation considerations in numerical model Author Plaxis (2004) Software Lining element Back-up loading Grout element Grout pressure Shield element Overcut Shield jacking Disturbed face element Face pressure PLAXIS3D Lim (2003) CRISP3D Mroueh & Shahrour (2002) PECPLAS Lin et al (2002) FLAC3D Melis... 40.0 30 30 G 4c 75 65.0 30 30 G4d 150 86.7 30 30 G4e 200 86.7 30 30 Note: Please see section 4.3.3 for definition of soil layering Table 4.3 Critical state parameters adopted for MCC and SDMCC models Soil layer κ λ Γ M G4a 0.018 0.113 1.8 1.113 G4b 0.023 0.104 1.9 1.200 G 4c 0.007 0.070 2.0 1.200 G4d 0.007 0.070 2.0 1.200 G4e 0.007 0.070 2.0 1.200 Note: Please see section 4.3.3 for definition of soil layering... et al (2002) FLAC3D Augarde & Burd (2001) OXFEM Sousa et al (2001) FLAC3D Guedes et al (2000) ABAQUS Dias et al (2000) FLAC3D Komiya et al (1999) Unknown Swoboda & Krisha (1999) FINAL Lee & Rowe (1991) FEM3D Maranha & Neve (2000) FLAC3D Not considered in analysis Considered in analysis 174 Table 4.2 Soil parameters adopted for Mohr-Coulomb model Soil layer Eu (MPa) E' (MPa) φ' (o) c (kPa) G4a 10 8.7... in SDMCC model Soil Granite residual soil (Ng et al., 1998; Ng et al., 2000) Granite residual soil (Anand et al., 2001) A n1 m1 B n2 m2 b2 4500 0.7 0.2 0.71 1.0 0.2 -0.62 11500 0.7 0.2 2.0 1.0 0.2 -0.62 Table 4.5 Parameters for bulk modulus in SDMCC model C n3 m3 D n4 m4 b4 800 1.0 0.2 1.2 1.0 0.2 -0.61 175 Table 4.6 Summary of EPBM advance rate Average progress rate (m/day) Tunnel drive Serangoon to... Parameters for bulk modulus in SDMCC model C n3 m3 D n4 m4 b4 800 1.0 0.2 1.2 1.0 0.2 -0.61 175 Table 4.6 Summary of EPBM advance rate Average progress rate (m/day) Tunnel drive Serangoon to Woodleigh Serangoon to Kovan SB NB SB NB 3.9 8.25 10.65 Maximum progress rate (m/day) 18 21 176 . Sep Oct Nov Dec Pier 32 Pilin g wor k Pile ca p construction Plinth castin g Entire stem p ou r SB tunnel at Pier 32 NB tunnel at Pier 32 VWSG readin g taken Pier 37 Piling work Pile cap construction Plinth. Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Pier 11 Piling work Pile cap construction Plinth casting Entire stem pour Flare head casting Casting of diaphragm Starting stub casting Casting of box. face pressure from shield machine. 2) Bearing capacity was checked via the comparison of reaction force at pile base with grouting or face pressure in tail void. - 1) Simple hand calculation.