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| Disturbing effect of excavation process of shield tunnel with extremely closed side piles |
| LIU Tao1, YANG Kexing2*, JIANG Lei1, HUANG Xufeng1, GAO Rui1, LIU Shiqi1
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1. The Third Engineering Co., Ltd., China Railway Seventh Group, Xian 710043, Shaanxi, China;
2. Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou 310012, Zhejiang, China |
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Abstract The security problems such as misalignment of the pile foundation and excessive deformation of the bridge are existed during the excavation of the shield tunnel of the Hangzhou Metro Line 3 at a very close distance to cross the viaduct pile foundation shield. The theoretical calculation method of soil movement model and the numerical simulation method of Midas GTS soft were used to calculate the construction of shield tunnels, and the ground settlement and pile foundation inclination during shield construction were analyzed. The results showed that, when the left or right line tunnels were excavated separately, the maximum settlement occurred at the tunnel vault and above the ground surface,and the settlement would gradually decrease to both sides. The theoretical calculation of the settlement was similar to the numerical simulation; after the completion of the excavation of the two-line tunnel, the maximum settlement occurred at the surface position between the two tunnels;the excavation of the left and right line tunnels caused the left and right swing excursion of the middle row pile foundation; the cutter parameters and the distance between the tunnel face and the pile foundation were the main factors affecting the deviation of the pile foundation; in addition, the shield and rock mass gap, the strength of the secondary grouting material after the segment affect the ground deformation to a certain extent, and indirectly affect the gradient of the pile foundation.
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Published: 07 July 2020
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