Factors Influencing the Longitudinal Deformation of Metro Tunnel in Soft Deposit: an Overview

(Jack) Shui-Long Shen

Shanghai Jiao Tong University

August 4, 2015

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 Outline  Introduction: situation of Shanghai  Influencing Factors  Land subsidence  tunnel construction  Construction of nearby engineering  Groundwater leakage  Dynamic loading of trains  Conclusions

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 2 Introduction

 Shanghai Metro Baoshan District Jiangding District Line 3 Line 1 Line 7 Line 11 Line 10 Line 6 Line 8 Outer Ring Road Chongming Jiangsu Island Urban Area Province Pudong New Development Area HIA Line 4 Line 2 Estuary of Line 2 Qingpu District Line 10 PIA Yangtze Maglev River Line 3 Line 1 Nanhui District N Line 5 Songjiang District Shanghai administrative region Minhang District 0 10 20 km Line 9 Line 5 East China Line Opened Length(km) Line Opened Length(km) Sea 1 1995 36.4 7 2009 44.2 2 1999 63.8 8 2007 37.5 Zhejiang 3 2000 40.3 9 2007 45.2 Hangzhou Province 4 2005 33.7 10 2010 35.4 Bay 5 2003 17.2 11 2009 45.8 6 2007 31.1 Total: 410

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 3 Introduction

 Urban Railway Transportation in Shanghai

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 4  Geological and Geotechnical Conditions

Power Cable Water Steam 3 m Gas ②3 Silt, Silty sand

③ Soft Silty Clay Metro Tunnel ④ Soft Clay 15 m ⑤1 Clay

⑤2 Sandy silt Sewerage ⑤3Clay ⑥ Clay

⑦1 Silt, Silty sand

Deep water pumping ⑦2 Silty Sand 40 m

Data from MLSMPG (2006)

Buried depth of the city facilities for Shanghai  Geological and Geotechnical Conditions

Grain-size distribution 3 Soil layers  ( kN/m ) w ,w , w (%) e c k ,k (cm/s) S , S (kPa) t n L P 0 c v h u ur (%) 0 50 100 18 2120 40 600.6 1.2 0.0 0.4 1E-8 1E-5 0.01 30 60 0 ② ② 1 2 ② 3 10 ③ ④ 20 ⑤ ⑥ 1

30 ⑥

Depth (m) ⑦ w 1 n w 40 L ⑦ w 2 P S ⑧ u <0.005mm 1 S 50 k ur 0.05~0.005mm v k ⑧ >0.05mm h 2 60 Note:  =unit weight; w = natural water content; w = liquid limit; w = plastic limit; e =void ratio; t n L P 0 c = compression index; k =vertical permeability; k = horizontal permeability; S = undrained shear c v h u strength; S = remoulded undrained shear strength. ur An illustration of geotechnical profile and soil properties in Shanghai Introduction

 Large cumulative settlement and substantial differential settlement

50 (St.=Station; Data from Chen 2000 &SMMR 2007) Cumulative settlement from 1995 to 1999 0 Cumulative settlement from 1995 to 2007 -50 -100 -150

-200

-250 Settlement (mm) Settlement -300

-350

Xujiahui St. Xujiahui

Caobao Road St. Road Caobao

Shanghai Indoor Stadium St. Stadium Indoor Shanghai St. Road Henshan

Changshu Road St. Road Changshu

South huangpi Road St. Road huangpi South

Xinzha Road St. Road Xinzha

South Shanxi Road St. Road Shanxi South St. Road Hanzhong People Square St. Square People -400 St. Railway Shanghai 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000 Distance (m) Cumulative settlement in up line of Metro Line 1

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 7  Long-term settlement of metro tunnels in soft ground

漕宝路站徐家汇站衡山路站常熟路站新闸路站汉中路站陕西南路站黄陂南路站人民广场站上海火车站 0 上海体育馆站 -50 1995 1997 ) -100 1998

mm 1999

( 2004 -150 2001

2007

-200 2003 2010 沉降量 -250 车站 -300 -350 2000 4000 6000 8000 10000 12000 14000 里程(m)

Observed cumulative settlement of ML No.1 since construction  Long-term settlement of metro tunnels in soft ground

Lujiazui Stn. Jiangsu Rd. Stn. LongyangCentury Rd. Stn. Park Stn. CenturyDongchang Avenue Stn. Rd.East Stn. NanjingPeople's Rd.West Square Stn. NanjingJing'an Stn. Rd. Temple Stn.Zhongshan Stn. Park Stn. 0Zhangjiang Hi-Tech Stn. Sci. &From Tech. 1999Museum to 2010Stn.

-50

-100 Ramp section Note: Rd.= Road, Stn.= Station -150 station cross passage

Cumulative settlement (mm) settlement Cumulative Data from SSMRC (2012) Crossing below Huangpu River 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 Mileage (m)

Observed cumulative settlement of ML No.2 since construction Influencing Factors

Construction of nearby engineering Tunnel Groundwater construction leakage

Dynamic Land Longitudinal loading of subsidence Deformation trains

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 10 Influencing Factors

Influencing factor Mechanism Time Foundation settlement due to Regional land subsidence Long-term regional land subsidence Consolidation and secondary consolidation of the soft clay Shield tunnel construction Short-term induced by the increase of excess pore water pressure Variation of stress and displacement caused by Deep pit excavation； excavation Consolidation of the soft clay Construction induced by dewatering Accidental of nearby Soil squeezed by pile Construction of short-term construction construction；Shear stress is piles induced after loading Soil squeezed by shield tunneling Construction of machine ; Unloading after tunnel bypass tunnels excavation Pore pressure dissipation; soil Accidental Groundwater leakage consolidation settlement long-term The cumulative deformation of Cyclic loading of trains Long-term soft soil under cyclic loading

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 11 Land subsidence (Influencing factors)

 Land subsidence in Shanghai & Causes 0

) -500

(

-1000

200mm -1500

-2000 Causes of land subsidence

 Dense urban construction Accumulated land subsidence land Accumulated rapid stable increasing  Excessive pumping of the -2500 groundwater 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year Development of land subsidence in Shanghai

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 12 Regional land subsidence (Influencing factors)

 Comparison between tunnel settlement and land subsidence.

0 Measured Point near Zhongshan Park Station. of Line No.2

-20

-40 Tunnel Settlement

-60 Land subsidence Settlement (mm)

-80 Data from SSMRC(2012) -100 0 300 600 900 1200 1500 1800 2100 2400 2700 (Mar., 2000) (Nov., 2008) Elapsed time (day)

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 13 .  Correlation and difference between tunnel settlement and land subsidence

Caobao Rd. Stn. People's Square Stn. Railway Stn. 月份 0 2009-6 2009-9 2009-12 2010-3 2010-6 2010-9 2010-12 Average speed in urban area v =16.1 mm/a ⑤层 ⑥层 ⑦ 层 ⑦ 层 ⑨层 + 1 + 2 + -50 0

②1层+部分③层 -100 -5

Cumulative settlement of tunnel ) -150 Ground surface subsidence mm 部分③层+④层

( -10

Rd.= Road, Stn.=Station Cumulative Settlement (mm) a) 1995~2000 -200

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 沉降量 -15 地面

People's Square Stn. Railway Stn. 0 Caobao Rd. Stn. -20 福山路浅式分层标组(FS7) -50 -25 0 90 180 270 360 450 540 时间(天) Average speed in urban area v =10.8 mm/a

-100 Cumulative settlement of tunnel Layered ground settlements near Pudian Road Station -150 Ground surface subsidence on ML 4 Rd.= Road, Stn.=Station b) 2001~2005 Cumulative Settlement (mm) -200 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 Tunnel settlement is correlated to sublayer Comparison between tunnel settlement of ML1 and land settlement under the tunnel rather than ground subsidence in time periods surface settlement  A method to evaluate the tunnel settlement caused by land subsidence

车站1 车站2 车站3 车站4 区间1 区间2 区间3

0.8~1.2 km 0.8~1.2 km 0.8~1.2 km 三次样条插值拟合

S1 S3 隧道沿线下方地层沉降量 S4 注：Si=车站i的沉降量 S2

Assumption: The stations are almost entirely caused by the local land subsidence Step: 1. Taking the stations as the layer-wise mark at the depth of tunnel 2. Using a cubic spline function to fit the line of the station points

 Tunnel settlement caused by land subsidence: ML1 in Shanghai

徐家汇站衡山路站常熟路站陕西南路站黄陂南路站新闸路站汉中路站漕宝路站人民广场站上海火车站上海体育馆站

0 50 100

) 150 mm

( 200

250

沉降量 settlement(mm)

300 隧道总沉降量地面沉降引起的隧道沉降量 350 1995-2010地面累积沉降量车站位置 400

Tunnel 2000 4000 6000 8000 10000 12000 14000 Mileage里程(m (m)) Cumulative tunnel settlement of ML1 caused by land subsidence (2010)  Tunnel settlement caused by land subsidence: ML2 in Shanghai

中山公园江苏路站静安寺站南京西路站人民广场站南京东路站陆家嘴站世纪大道站世纪公园站 -30 东昌路站上海科技馆站龙阳路站

30 )

mm 60 ( 90

沉降量 120 隧道总沉降量地面沉降引起的隧道沉降量 150 车站

180 12000 14000 16000 18000 20000 22000 24000 26000 28000 里程 (m) Cumulative tunnel settlement of ML2 caused by land subsidence (2010)  Tunnel settlement caused by land subsidence

300

线性拟合 2010年

2号线 ) 250

1号线

( Tunnel 200

(mm) 2 y =0.625x,R =0.8697

150

Induced

100

subs.

settlement

Land 地面沉降引起的隧道沉降量

0 0 50 100 150 200 250 300

Total tunnel隧道总沉降量 settlement(mm )(mm)

RelationshipEquation betweeny = a + b*x tunnel settlement caused by land subsidence and the Weight No Weighting Residual Sum of 9574.96864 total settlement Squares Adj. R-Square 0.94303 Value Standard Error B Intercept 0 -- B Slope 0.64472 0.03837 Tunnel settlement caused by other factors

徐家汇站衡山路站常熟路站陕西南路站黄陂南路站人民广场站新闸路站汉中路站漕宝路站上海火车站上海体育馆站 150 车站位置Station (mm) 100 其他因素引起的隧道沉降量Other factor setl. (mm)

) 50 mm

( 0

settlement

沉降量 -50

-100 P1 P4 P3 P2 Tunnel -150 2000 4000 6000 8000 10000 12000 14000 里程(m) Mileage (m)

Shanghai Metro Line No. 1 (2010)  Tunnel settlement caused by other factors

中山公园江苏路站静安寺站南京西路站人民广场站南京东路站陆家嘴站东昌路站世纪大道站上海科技馆站世纪公园站龙阳路站 150

100

(mm)

) mm

( 0

-50 沉降量

settlement 车站 Station -100 其他因素引起的隧道沉降量Other factor setl. (mm) -150 Tunnel 12000 14000 16000 18000 20000 22000 24000 26000 28000

里程(m)

Shanghai Metro Line No. 2 (2010)  Tunnel settlement versus time (P1~P4)

年份年份 1995 1997 1999 2001 2003 2005 2007 2009 1995 1997 1999 2001 2003 2005 2007 2009 0 0 20 50 40

) 60

) 100

mm 80

(

mm (

100 150

沉降量 120 位置：P1 沉降量位置： 200 P4 140 隧道沉降量隧道沉降量 160 地面沉降引起的隧道沉降量地面沉降引起的隧道沉降量其他因素引起的隧道沉降量 250 其他因素引起的隧道沉降量 180 拟合值拟合值 200 0 2 4 6 8 10 12 14 300 0 2 4 6 8 10 12 14 时间(年) 时间(年) Tunnel construction (Influencing factors)

 Settlement profiles during tunneling

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 22 Construction of nearby engineering

Pit Excavation of Tunnel foundation pit

Construction and of piles Piles

Construction of bypass Tunnel tunnels

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 23 Groundwater leakage (Influencing factors)

 Characteristics of leakage

Local groundwater leakage: (a) at joints between rings; (b) at cross joints; (c) at grouting holes

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 24 Groundwater leakage (Influencing factors)

 Leakage phenomenon

-5 0 k =3.310 m/s j -6 150 330 30 k =3.310 m/s j Origin -7 k =3.310 m/s j -5 -8 k =3.310 m/s 100 k =3.310 m/s j 300 60 j -9 -8 k =3.310 m/s

j k =3.310 m/s ) -10 j 50 k =3.310 m/s kPa j -9

( -11 k =3.310 m/s k =3.310 m/s j j 0 270 90

1 mm

50 Pore water pressure water Pore 240 120 100 Scale =1:1000

150 210 150 Inclined ellipse 180 Angle () Pore water pressure around tunnel Diametrical distortion of (steady state) segmental lining due to leakage

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 25 Dynamic loading of trains (Influencing factors)

45  Dynamic finite/infinite element method 40

• Dynamic constitutive model ) 35

kPa ( • Too time-consuming 30

 Empirical equations 20 Deviatoricstress • Monismith et al. (1975) 15 • Li and Selig(1996) 10 0.00 0.05 0.10 0.15 0.20 • Chai and Miura(2002)  (%) P Permanent plastic strain of soil under cyclic load

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 26 Dynamic loading of trains (Influencing factors)

 Rail-fastener-roadbed & lining-foundation model (Wu et al. 2014)

2.5 m 13.2 m 2.5 m 4.6 m 2.5 m 13.2 m 2.5 m 4.6 m 2.5 m 13.2 m 2.5 m

Pd11 Pd12 Pd13 Pd14Pd21 Pd22 Pd23 Pd24 Pd31Pd32 Pd33 Pd34

0 1 2 Rail n-1 n Fastener k1 0.595 m Roadbed and lining

k2 Elastic foundation

A simplified mechanical model

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 27  Calculation results (Wu et al., 2015)

Vertical strain  (%) p 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0 0

5 10

)

) m

( CL

mm 20

10 (

15 30 v=10 km/h

2 month v=20 km/h 1 year v=30 km/h 20 10 years 40 v=40 km/h 50 years 7~12 mm after 1 year Depth below tunnel below Depth v=50 km/h 100 years settlement Tunnel 12~18mm after 10 years 25 50 v=60 km/h running speed v=60km/h v=70 km/h v=80 km/h 30 60 0 10 20 30 40 50 60 70 80 90 100 Time (year) Vertical plastic strain with depth under train load (v=60 km/h) Predicted settlement varied with the elapsed time

Wu, HN, Shen, SL., Zhang, DM et al. (2015). Geotechnical Engineering, ICE Proc. Conclusions

(1) In order to control the long-term deformation of metro tunnel and to ensure the safety of tunnel structure, it is very important to understand the causes of tunnel deformation. The main factors influencing the longitudinal deformation of metro tunnel are: (i) regional land subsidence, (ii) shield tunnel construction, (iii) construction of nearby engineering, (iv) groundwater leakage, and (v) dynamic loading of trains.

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 29 Conclusions

(2) The influence of regional land subsidence and dynamic loading of trains is throughout the operation duration. Effect of shield tunnel construction is small on the tunnel long-term settlement. Groundwater leakage is stochastic, however, if the leakage is not blocked in time, the influence of the leakage will be long-term. Disturbance from adjacent projects construction is also stochastic, and the influence is short-term.

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 30 Conclusions

(3) Based on the assumption of station settlement is main induced by land subsidence. Land subsidence induced settlement of tunnel was identified with the amount of about 62% of total tunnel settlement. The settlement induced by other reasons, e.g. train vibration, groundwater leakage, etc. was only 38% for the metro tunnels in Shanghai.

(4) However, it is difficult to identify all of the reasons for the tunnel settlement, because these influencing factors interact with one another.

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 31 Thank you!

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015 32