ISSN 2096-4498
CN 44-1745/U
ISSN 2096-4498
CN 44-1745/U
Numerical Analysis of Face Stability of LargeDiameter Slurry Shield Used in Mawan Subsea Tunnel in Complex Strata
(1.China Railway Southern Investment Group Co., Ltd., Shenzhen 518000, Guangdong, China; 2. Department of Geotechnical Engineering College of Civil Engineering, Tongji University, Shanghai 200092, China)
Online published: 2021-08-27
A largediameter slurry shield used in Mawan subsea tunnel continuously crosses through fullface soft stratum, uppersoft and lowerhard strata, and fullface slightlyweathered rock stratum. To investigate the influence of slurry pressure of slurry shield on face stability under complex strata conditions, 3D numerical simulation models under different strata are established to obtain corresponding displacement distribution laws and ultimate minimum supportstress ratio of tunnel face. In addition, the rectangular load mode is often used to simplify the slurry pressure in previous researches, the differences between the actual trapezoidal load mode and the simplified rectangular load mode in the stability analysis of tunnel face are compared and analyzed. The results show the following. (1) In the case of fullface soft stratum, the displacement of the tunnel face is relatively uniform in the middle of tunnel face, while it is quite different at both ends, whereas in the uppersoft and lowerhard strata, the displacement decreases linearly from the arch crown to the bottom. (2) The maximum supportstress ratio of the tunnel face obtained by tangent intersection method is the largest in the fullface soft stratum, followed by that in uppersoft and lowerhard strata, and that in the fullface slightlyweathered rock stratum is the smallest. (3) In the case of trapezoidal load distribution, both the upper soil displacement and the obtained ultimate minimum support stress ratio are far larger than that of rectangular load distribution, indicating that it is unreasonable to ignore the influence of unit weight of slurry in calculation.
LIU Jiqiang, CHEN Xiaoqing, ZHANG Xiaodong, QIAO Yafei
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Numerical Analysis of Face Stability of LargeDiameter
Slurry Shield Used in
Mawan Subsea Tunnel in Complex Strata
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