Study on Face Stability of EPB Shield Tunnels in Granular Materials

被引：0
|
作者：
Wang J. [1 ,2 ]
Nie L. [1 ]
Xiang L. [1 ]
He C. [2 ]
机构：
[1] Sichuan Provincial Transportation Department Highway Planning, Survey, Design and Research Institute, Chengdu
[2] Key Laboratory of Transportation Tunnel Engineering, Ministry of Education, Southwest Jiaotong University, Chengdu
来源：
He, Chuan (chuanhe21@163.com) | 2018年 / Science Press卷 / 40期
关键词：
3D DEM; EPB shield; Face stability; Granular material; Shield tunneling;
D O I：
10.3969/j.issn.1001-8360.2018.07.019
中图分类号：
学科分类号：
摘要：
Three dimensional discrete element method (3D DEM) was used to study the face stability of earth pressure balance (EPB) shield tunnel in granular materials incorporating the dynamic shield tunneling process. The study was finished in two steps: (1) The DEM model reproducing the laboratory test conducted by Fan and Zhang[14] was first established. The rationality of the numerical method was verified by comparison of the results between the two models. (2) The validated numerical method was used to model the prototype EPB shield tunneling in typical granular materials to study the influence of buried depth, soil properties and tunneling process on face stability and to observe the tunnel failure process microscopically. The results indicate that the shield construction process weakens the stability of the face, causing the increase of the limit support pressure pf. The degree of influence is related to the opening ratio of cutter disc and the tunneling excavation state. The pf decreases with the increase of frictional angle in granular materials. For dry sand and sandy cobble stratum, pf grows almost linearly with the buried depth of the tunnel, while in dense sandy cobble, pf stabilizes with greater buried depth. When the tunnel is shallow, the failure zone develops to the surface, while with larger buried depth, stable soil arch exists above the tunnel crown. The distribution range of the instability zone decreases with the increase of the internal friction angle. The research results may serve as certain guidance to guarantee the stabilization of excavation face of shield tunnels in granular material. © 2018, Department of Journal of the China Railway Society. All right reserved.
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页码：128 / 135
页数：7
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