Effects of tunnel construction on nearby pile foundations 4

a b Figure 2.14 Pilot test carried out at Second Heinenoord tunnel site a Test layout b Zone of influence Kaalberg et al., 2005 Legend: Zone A: Pile head settlement > Soil surface settl

Piled-raft

Piles

Pile cap Soil movement

Lateral deflection

Figure 1.1 An illustration of pile responses caused by tunnel construction (a) Tunnelling

under pile foundation (b) Tunnelling adjacent to pile foundation

Type 1

Type 3

Type 4

Type 2

Angel Underground Station, London MRT North-East Line C704, Singapore MTR Island Line, Hong Kong

MRTA Subway, Bangkok Electric Power Tunnel, Japan

Tokyo Subway Line 7, Japan Jubilee Line Extension, London Channel Tunnel Rail Link 2, London MRT Circle Line C825, Singapore

North/South Metroline, Amsterdam

Existing super- structure

Current design and assessment approach for pile responses subjected to tunnelling

* Broms & Pandey (1987)

* Sawatparnich & Kulhawy (2004)

2-D finite element method

* Vermeer & Bonnier (1991)

* Lee et al (1994)

3-D finite element method

* Mroueh & Shahrour (2002)

Figure 2.3 Angel Underground Development in London (Mair, 1993; Lee et al., 1994)

(a)

(b)

Figure 2.4 Tunnelling for the Jubilee Line Extension in London (a) Under building

(Powderham et al., 1999) (b) Adjacent to building (Selemetas et al., 2002)

(a)

(b)

(c)

Figure 2.5 Tunnelling for the Channel Tunnel Rail Link 2 (a) Renwick Road bridge (b)

Ripple Road Flyover (c) A406 viaduct (Jacobsz et al., 2005)

Figure 2.6 Tunnelling adjacent to bridge pier in Japan (Moroto et al., 1995)

Figure 2.7 Tunnelling under various constraints from pile foundations (Nakajima et al.,

1992)

Figure 2.8 Tunnelling under large dome stadium supported by pile foundations (Inose et

Higashi-Figure 2.10 1-g model set up to simulate tunnelling effect on pile foundation (Morton &

King, 1979)

Figure 2.11 Centrifuge test set up to simulate tunnelling effect on pile foundation

(Hergarden et al., 1996)

Figure 2.12 Zone of influence around tunnel in which potential for large pile settlement

exists (Jacobsz et al., 2002)

(a)

(b) Figure 2.13 Load transfer mechanism for (a) long pile (b) mid-length pile (Lee & Chiang,

Piles that underwent "large" settlements Piles that underwent "small" settlements Area where "large" settlements might be expected

(a)

(b)

Figure 2.14 Pilot test carried out at Second Heinenoord tunnel site (a) Test layout (b)

Zone of influence (Kaalberg et al., 2005)

Legend:

Zone A: Pile head settlement > Soil surface settlement Zone B: Pile head settlement = Soil surface settlement Zone C: Pile head settlement < Soil surface settlement

Figure 2.15 Zone of influence around EPB tunnel in London Clay (Selemetas et al., 2005)

Legend:

Zone A: Pile head settlement > Soil surface settlement Zone B: Pile head settlement = Soil surface settlement Zone C: Pile head settlement < Soil surface settlement

Zone A

Zone C

Check on pile settlement (Jacobsz et al., 2005)

Assumptions:

1) Reduction of pile base load during

volume loss not possible to mobilise

significant shaft friction loads

2) Pile settlement = Pile base settlement

Calculate greenfield settlement at pile base using empirical models such as:

* New & Bowers (1994)

* Mair et al (1993)

Assumptions:

1) Reduction of pile base load during volume loss is transferred to pile shaft 2) Pile settlement = Pile surface settlement

Convert vertical and horizontal displacement to strains

Compare and check strains to be less than

ultimate strain of pile's material

Check on pile bearing capacity during shield advancement (Nakajima et al., 1992)

pile base and vertical soil loading with resistance

pressure above tail void for width of 1 segment ring) and Pr (i.e face pressure entering tail section + total skin friction due to soil mass) with FOS

Check on pile bearing capacity (Inose et al., 1992)

A cone is imagined below a pile Punching shear

resistance acting on the cone is assumed to be the

bearing capacity Compare the bearing capacity with

the loading (Q) acting on the pile

Mitigation works required (such as grouting between tunnel and pile base) Safe

(e)

Figure 2.16 Empirical method of assessment for (a) pile settlement (b) pile overstress (c) pile bearing capacity during shield advancement (d) pile bearing capacity due to tail void grouting (e) pile bearing capacity assuming an imaginative cone (continue)

Figure 2.17 Load-settlement curve from FE simulation of pile load test (Lee & Ng, 2005)

Legend

Pf = Face pressure

Pw = Pore water pressure

τ = Friction force

MRT NORTH-EAST LINE

Serangoon Station Woodleigh Station

Contract 704

LEGEND

MRT STATION

Figure 3.1 Location of the MRT North East Line in Singapore

TUNNEL ADVANCING DIRECTION

Piers 32,

37 & 38 Pile foundation

Figure 3.2 Location of piled foundation supporting bridge viaducts and tunnels

SEA SEA

SENTOSA ISLAND

Old Alluvium

Bkt Timah Granite

Kallang Formation

Jurong Formation

(a)

(b)

Figure 3.3 Geological profile along MRT North East Line (a) plan view (b) cross section

Shirlaw et al (2003)

MX6006

& I6006 MX6005

NB Tunnel

SB Tunnel

1.6m 3.3m

South bound tunnel

North bound tunnel

1.5m 1.5m

-800 -700 -600 -500 -400 -300 -200 -100 0

Serangoon

Station

Woodleigh Station Tunnelling direction

Figure 3.7 Maximum surface settlement measured at tunnel axis from Serangoon Station

Final immediate settlement

Face loss

Tail void closure

Figure 3.8 Surface settlement due to (a) SB tunnel advancement (b) NB tunnel

advancement at Pier 20

SB tunnel passed

NB tunnel passed

Figure 3.9 Development of surface settlement with time above SB and NB tunnel axes at

NB

Figure 3.10 Surface settlements due to twin tunnels at Pier 20 section

SB tunnel passed

NB tunnel passed 2m

29m

16.4m

SB NB

SB tunnel passed

NB tunnel passed 2m

29m

16.4m

SB NB

2m

(b)

Figure 3.11 Subsurface vertical soil movements at Pier 20 (a) MX6006 (b) MX6005

0 0.01

0 0.01

Tunnel

s pringline

EPBM

(b)

Figure 3.12 Lateral soil deflection measured in inclinometer I6006 at Pier 20 (a) due to

SB tunnel (b) due to SB + NB tunnels

Tunnel springline

2m 29m

0 0.01

Tunnel springline

0 0.01

Tunnel springline

EPBM

(b)

Figure 3.13 Lateral soil deflection measured in inclinometer I6005 at Pier 20 (a) due to SB

tunnel (b) due to SB + NB tunnels

NB tunnel passed Pier 20

A B

1.7m 3.3m

16.4m A B

SB NB

NB Tunnel passed Pier 20

NB

E

H G F SB

A B C D

Figure 3.15 Development of axial force in pile P1 at Pier 20 due to EPBMs advancement

-6000 -4000

-2000 0

H G F SB

A B C D

Pie r 20 P2 P1

Figure 3.16 Maximum measured axial force in piles at Pier 20 due to both SB and NB

tunnels

Average pile axial force for Pile P6 (Pier 11)

G

E F

H

SB Tunnel passed Pier 11

NB Tunnel passed Pier 11

NB

E

H G F SB

A B C D

Average pile axial force for Pile P3 (Pier 14)

C

A B

D

SB Tunnel passed Pier 14

NB Tunnel passed Pier 14

NB

E

H G F SB

A B C D

(b)

Figure 3.17 Development of axial force in (a) pile P6 at Pier 11 (b) pile P3 at Pier 14 due

to EPBMs advancement

Figure 3.19 Measured bending moment in piles P1 and P2 at Pier 20 (a) transverse

direction (b) longitudinal direction

-30000 -25000 -20000 -15000 -10000 -5000 0 5000

Transverse bending moment, Mxx (kNm)

Transverse bending moment, Mxx (kNm)

Longitudinal bending moment

M yy in pile P1 (Pier 20)

C A B D

SB tunnel passed Pier 20

NB tunnel passed Pier 20

-30000 -25000 -20000 -15000 -10000 -5000 0 5000

Longitudinal bending moment, Myy (kNm)

Longitudinal bending moment, Myy (kNm)

Axial force in pile P1 (Pier 20)

NB tunnel passed Pier 20

Approximately 1 year later

Entire stem pour

Flare head casting

Diaphragm casting

Box girder and deck slab casting

Figure 3.23 Post-tunnelling measurement of the development of axial force in pile P1 at

-6000 -4000

-6000 -4000 -2000

Tunnel springline

Figure 3.25 Effect of post-tunnelling loading on the bending moment response of pile P2

(a) transverse direction (b) longitudinal direction

-10000 -9000 -8000 -7000 -6000 -5000 -4000 -3000 -2000 -1000 0

Figure 3.27 Relationship between axial force and volume loss due to SB tunnel

advancement (a) 1.2m diameter pile (b) 1.8m diameter pile

Figure 3.28 Relationship between axial force and volume loss due to SB and SB+NB

tunnels advancement

(a)

(b)

v er se b en din

g m om

v er se b en din

g m om

al be nd in

g m om en

t, M

yy

(k Nm )

al be nd in

g m om en

t, M

yy

(k Nm )

0 200 400 600 800 1000 1200 1400

P5/P6 Pier 11

P3/P4 Pier 14

P1/P2 Pier 20

P7/P8 Pier 32

P9/P10 Pier 37

P11/P12 Pier 38

Positive effect

Figure 3.32 Ratio of front pile to rear pile response due to SB tunnel advancement

0 1000 2000 3000 4000 5000 6000 7000 8000

Estimated (Front pile) Estimated (Rear pile)

(a)

0 250 500 750 1000 1250 1500

Measured (Rear pile)

P3 P4 P1 P2 P11 P12 Pier 14 Pier 20 Pier 38

Estimated (Front pile) Estimated (Rear pile)

(b)

Figure 3.33 Comparison of estimated and measured pile responses (a) dragload (b)

transverse bending moment

(1) Face intrusion

(2) Over-excavation (3) Tail void closure

(4) Lining deformation /

Consolidation

Figure 4.1 Idealised steps in shield tunnelling

Figure 4.2 Gap approximation technique in 3-D finite element analysis (Lee & Rowe,

1991) Advancing direction Advancing direction

Figure 4.3 Full shield tunnel advancement technique (Komiya et al., 1999)

Figure 4.4 Lining shrinkage technique (Augarde et al., 1998)

Figure 4.5 Modelling of EPB shield tunnel advancement (Lim, 2003)

Figure 4.6 Grout pressure model (Plaxis, 2004)

Stage A

Stage B

Advancing direction

Advancing direction

(a)

Figure 4.7 Typical finite element mesh used to simulate the pile group subjected to (a)

single tunnel advancement (b) twin tunnels advancement

1.5m

60.5m

5.3m 5.3m

Lining Shield machine

Over-cut

Grouting

Soil

(b)

Figure 4.7 Typical finite element mesh used to simulate the pile group subjected to (a)

single tunnel advancement (b) twin tunnels advancement (continue)

105m

140m

G4a G4b G4c

72m

33m

TUNNEL ADVANCE DIRECTION

Soil element

Over-cut element Shield element Liquid grout element

Lining element

Face pressure

Face pressure

Step i+2

Hardened grout element

Figure 4.8 Finite element simulation procedure for shield tunnel advancement

Pier 20

NB

Figure 4.9 Typical soil profile simulated in the FE analysis

Figure 4.10 State boundary surface in SDMCC model

S

Critical state line

Roscoe surface

M M = Critical state ratio

H = Slope of Hvorslev surface

S = Slope of no-tension cut-off line

εqp

2 2 2

P B

(Anand et al., 2001)

Figure 4.12 Degradation of normalised shear modulus with shear strain derived from

Figure 4.13 Measured maximum shear modulus from CSWS (Anand et al., 2001)

(Site 1)

Lab test

SBPM &

Geophysic method (Site 2)

Geophysic method (Site 1)

Ng & Wang (2001)

(b)

Figure 4.14 Variation of (a) shear modulus (b) bulk modulus with strain in granites

residual soil in Hong Kong

No of r ings built/day

No of r ings built (ac c umulated)

SB tunnel pas s ed Pier 11, 14 & 20

Figure 4.15 Progress for South bound tunnel drive from Serangoon Station to Woodleigh

(a)

Figure 4.16 Effect of tunnel advancement rate on (a) transverse surface settlement (b)

longitudinal surface settlement (c) excess pore pressure

-20 -10

0 10

20 30

Node 21243

(c)

Figure 4.16 Effect of tunnel advancement rate on (a) transverse surface settlement (b)

longitudinal surface settlement (c) excess pore pressure (continue)

Figure 4.17 Surface settlement troughs at different face pressure

Soil element

Over-cut element Shield element

Face pressure

Face pressure

Grouting pressure

Face pressure

6.5m

Grouting pressure

Grout element Lining element

advancing section (b) cross-section

GP model (Pgrout.upp=150kPa, Pgrout.bott=350kPa, 6m slice) Measured

Figure 4.21 Effect of grout pressure length on the surface settlement trough

Figure 4.22 Settlement troughs for varying lining stiffness

(Ng et al., 1998, 2000) (Anand et al., 2001)

Figure 4.23 Surface settlement troughs predicted by various soil models

-20 -10

0 10

20 30

At x=0m, y=33m, z=0m

SB

Figure 4.24 Longitudinal surface settlement profile using SDMCC model

Figure 4.25 Earth pressure at-rest of the Bukit Timah Granite residual soil from

pressuremeter test (Lim, 2003)

(b)

Figure 4.26 Surface settlement troughs for varying Ko parameter (a) MC model (b) MCC

(c) SDMCC model

(c)

Figure 4.26 Surface settlement troughs for varying Ko parameter (a) MC model (b) MCC

(c) SDMCC model (continue)

-15 -10

Figure 4.27 Subsurface horizontal soil movement for varying Ko parameter (a) Transverse

direction (b) Longitudinal direction

21m Monitoring array

Figure 4.29 Surface settlement troughs for varying artificial boundary fixity

Case 4 (e) Case 5

-20 -10

0 10

20 30

-30 -20

-10 0

10 20

30 40

SB

Figure 4.34 Development of excess pore pressure due to SB tunnel

Greenfield analysis Tunnel-pile analysis Measured data (Greenfield)

Greenfield analysis Tunnel-pile analysis Measured data (Greenfield)

-10 -5

0 Lateral deflection - transverse (mm)

(a)

+18m +6m 0m -6m -18m -27m (+3D) (+1D) (0D) (-1D) (-3D) (-4.5D)

Tunnel

advancement

Tunnel springline

Tunnel

face

position

-2000 -1000

-3000 -2000 -1000

-3000 -2000 -1000

Tunnnel springline

Pile P2

0 D SB

-3000 -2000 -1000

Tunnnel springline

Pile P2

-1.5D SB

Figure 4.37 Predicted and measured axial force in pile P2 at different distance of tunnel advancement (a) +3Dtun (b) +1.5Dtun (c) 0Dtun (d) -1.5Dtun (e) -3Dtun (f) -4.5Dtun

-2000 -1000

Tunnnel springline

Pile P2

-3D SB

-3000 -2000 -1000

Tunnnel springline

Pile P2

-4.5D SB

Figure 4.37 Predicted and measured axial force in pile P2 at different distance of tunnel advancement (a) +3Dtun (b) +1.5Dtun (c) 0Dtun (d) -1.5Dtun (e) -3Dtun (f) -4.5Dtun (continue)

-5000 -4500 -4000 -3500 -3000 -2500 -2000 -1500 -1000 -500 0

1

3

Figure 4.38 Force-moment interaction curves at different stages of tunnel advancement

-5000 -4500 -4000 -3500 -3000 -2500 -2000 -1500 -1000 -500 0

Figure 4.39 Variation of face pressure on pile maximum axial force and pile head

Figure 4.40 Variation of face pressure on pile maximum lateral deflection

-2000 0

Figure 4.41 Axial responses of pile P1 for varying pile head condition (a) Pile axial

force (b) Pile settlement

SB

Figure 4.42 Lateral responses of pile P1 for varying pile head condition (a) Transverse

direction (b) Longitudinal direction

-3000 -2000 -1000

-3 -2

-1 0

SB

Figure 4.43 Effect of varying pile stiffness on pile response (a) axial force (b) settlement

(c) transverse lateral deflection (d) longitudinal lateral deflection

Tunnel springline

SB

(a) (b) Figure 4.44 Effect of Ko variation on bending moment of pile P1 (a) Transverse direction

-2000 -1000

Tunnel springline

(a) (b)

Figure 4.45 Effect of Ko variation on pile axial force (a) Pile P1 (b) Pile P2

-5000 0

Final load transfer (WL+tunnelling)

Load transfer due

-5000 0

Final load transfer (WL+tunnelling)

Load transfer due

-10 -5

-15 -10

SB

Figure 4.46 Effect of pre-tunnelling loading on pile responses (a) Axial force (b) Settlement (c) Transverse lateral deflection (d) Longitudinal lateral deflection