1、EM M SEGEOTEC MERGIN MODELI ELECTED GE Geo- P C HNICAL GEO NG TECH ING, DE PAPERS EO-CHINA Shando Chine -Institute o J ShPublished b L SPECI O-CH HNOLOGI ESIGN, C REHAB FROM TH A INTERN July 2 Shan SPON Shando ong Depar Universi ese Nation of the Ame ED James C. Junsheng Y hong-loong Tong Q by the A
2、mer IAL PUB HINA IES IN T CONSTRU BILITATI HE PROCE NATIONA 2527, 201 dong, ChinNSORED BYong Univer rtment of T ty of Oklah nal Science rican SocieDITED BY . Ni, Ph.D. Yang, Ph.D g Chen, Ph Qiu, Ph.D., rican Society B LICATIO A 20 TUNNEL E UCTION, TION EEDINGS AL CONFE 16 na Y rsity Transportat homa
3、 e Foundatio ety of Civi ., P.E. D., P.E. h.D., P.E. P.E. y of Civil En ON NO. 16 ENGINEREPAIR OF THE F ERENCE tion on il Engineer ngineers 260 EERING, R, AND FOURTH rs Published by American Society of Civil Engineers 1801 Alexander Bell Drive Reston, Virginia, 20191-4382 www.asce.org/publications |
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10、 United States of America. Preface This Geotechnical Special Publication contains 34 peer-reviewed technical papers presented at the 4th GeoChina International Conference: Sustainable Civil Infrastructures: Innovative Technologies for Severe Weathers and Climate Changes, which took place in Shandong
11、, China, from July 25 to 27, 2016. This proceeding examines topics such as: - Tunnel Management and Inventory, Monitoring and Settlement Control - Emerging Technologies, Lining Design Junsheng Yang 2 ; and Shuangting Zhu 31 Postdoctoral Researcher, School of Civil Engineering, Central South Univ., C
12、hangsha 410075, China. E-mail: 2 Professor, School of Civil Engineering, Central South Univ., Changsha 410075, China. E-mail: 3 Power China Huadong Engineering Corporation Limited, HangZhou 310014. E-mail: Abstract: Technical measures, such as underground partition wall, could sever as recourse t
13、o mitigate the ground movements induced by excavation. In this paper field monitoring and numerical analysis were used to examine the performance of underground jet-grouted partition wall in mitigating the effects of shield tunnel construction on existing pier of Xin-Zhong-Road viaduct in the projec
14、t of Changsha Subway Line 1 in China. The performance of the jet-grouted partition wall was calibrated by the reasonable agreement found between the observed field measurements and the numerical results. Underground jet-grouted-column partition wall was testified to serve as an effective measure in
15、ground movement control given the need of tunnelling nearby piled structures. 1 INTRODUCTION Tunnelling in urban areas may cause damage to buildings founded adjacent. Underground partition wall installed between the buildings and the tunnel was expected to cut off the displacement induced by tunnell
16、ing so that the nearby buildings can be protected. Some researches have been carried out to study the mechanism of underground partition wall in reducing the damage impact of tunnelling to adjacent structures. Harris et al. (1994) presented that the compensation grouting could effectively reduce the
17、 ground settlement and nearby building distortion. Bilotta and Taylor (2005) carried out centrifuge tests to study how the diaphragm wall reduces the tunnelling induced movements at the two side of the wall. Kirsch and Piazzi (2009) also identified the influential parameters of bored pile wall to pr
18、otect sensitive buildings from settlement resulting from tunnelling using numerical simulations. They concluded fully mobilized friction between soil and wall leads to no significant reduction of settlement on the far side of the wall. Bilotta (2008) performed a series of centrifuge tests and Geo-Ch
19、ina 2016 GSP 260 1 ASCE numerical analyses to investigate the effects of a diaphragm wall. They found length and thickness of the wall, and the roughness of the soil-wall interface, the length of the wall plays the main role in the effectiveness of reducing ground movements. Wu et al. (2012) studied
20、 the pile wall in controlling the tunnelling effects on the nearby wood piles of a church through a numerical analysis. Zou and Xu (2013) carried out three-dimensional numerical simulation to investigate the mitigation effects of the separation pile and diaphragm wall to tunnel induced ground moveme
21、nts, considering the effects of soil at small strain stiffness. In this paper, the performance of underground jet-grouted partition wall in mitigating the effects of shield tunnel construction on existing pier of Xin-Zhong road viaduct in the project of Changsha Subway Line 1 was examined based on f
22、ield measurements and numerical analysis. The performance of the jet-grouted partition wall in reducing the tunnelling influence on the adjacent pier is illustrated by a comparison between the field measurement and numerical results. The effectiveness of using jet-grouted underground partition wall
23、in reducing tunnelling induced displacement was testified and discussed. 2 PROJECT OVERVIEW 2.1 Construction techniques The tunnelling project referred to is located closely on the east side of L-off-ramp of Xinzhong-road viaduct in the project of Changsha Subway Line 1, as shown in Figure 1. The co
24、nstruction consists of two parallel tunnels. The two tunnels are circular and their axes are 21.5 m below the ground surface level while there is a central line separation of 17.3 m between them. The studied tunnel section is about 155 m long from the distance mark DK24+245 to DK24+400. Composite EP
25、B shield tunnel boring machine of 6.25 m diameter was used to construct the tunnels. Each construction cycle involved an excavation in advance of the shield 1.5 m to install the segment lining before shoving the shield forward. The precast concrete segments were each 0.3 m thick. Each segment ring w
26、as formed from 6 precast concrete segments and has an internal diameter of 5.4 m. Six piers of the L-off-ramp of Xinzhong Road viaduct are situated on the east side of the east bound tunnel, and their marks vary from L01# to L06#. Each pier was founded by four piles except L01# was supported by a si
27、ngle pile. The distances from the piles to the tunnel central line vary between 6.7 to 9.9 m, which was no more than 1.5 times of the tunnel diameter. The pier L04# is located at DK24+330 founded by four friction-cum-end bearing piles. Each pile has a diameter of 1.2 m enlarging to 1.8 m at the end
28、and is separated by a spacing of 3 m to the other piles. The distance of the nearest pile to the tunnel profile was 6.9 m. In order to minimize the tunnelling effect on the pier, three rows of jet-grouted piles were installed to form a at least 4 m wide underground partition wall to protect the pier
29、 from tunnelling induced deformation. The jet-grouted columns have a diameter of 0.8 m while their axis spacing is 0.5 m. That means there is always about 0.3 m jet-grouted Geo-China 2016 GSP 260 2 ASCE column body interlocked with the adjacent one. As a result, the jet-grouted columns can act as an
30、 underground wall to partition the soil movements off. Since the piles of pier L04# are founding above the tunnel invert level, this paper focuses on the analysis of using jet-grouted column wall to mitigate the influence of tunnelling on the piled-pier L04#. Figure 1 plane view and geologic profile
31、 of the Changsha Subway Line 1 pass through the L-off-ramp of Xinzhong-Road viaduct 2.2 Geological condition The shield tunnel drove in the clayey sandy gravel with pebble ground which is overlain by silty clay followed by plain fill up to the ground surface. The typical geological condition at the
32、transverse section of pier L04# was also shown in Figure 1. The clayey sandy gravel with pebble consists of silty clay, silica sand, gravel and pebble, among which the silica sand is the main content mixed with mud. Site investigation shows that the soil contains 50.7% to 62.7% grain coarser than 20
33、 mm while it contains 20% sand grain finer than 2 mm, and the fines are less than 10%. This manifests that the tunnel is tunnel ground surface 52.41 silty clay conglomerate pebble plain fill clayey sandy grevel with pebble pier L04# 1.2/1.8m L14m 36 . 0 0 29.00 pier L03# 1.2/1.7m L21m 31.00 pier L02
34、# 1.2/1.7m L19m pier L05# 1.2/1.6m L20m 34.00 pier L06# 1.2/1.6m L20m 34.00 pier L01# 1.2/1.8m L19m 29.00 L06# L02# L03# L04# L05# L01# East bound tunnel DK24+400 DK24+330 North mileage mileage centreline of L-off-ramp of Xinzhong Road viaduct Tunnelling direction West bound tunnel DK24+340 mileage scale 10 m Geo-China 2016 GSP 260 3 ASCE
