Deformation Behavior of Topographic Unsymmetrical Loaded Tunnels and Their Pre-reinforcements after Excavation
YANG Chao1, ZHANG Yong-xing1,2, HUANG Da1,2, ZHU Qian3
1. College of Civil Engineering, Chongqing University, Chongqing 400045, China;
2. Key Laboratory of New Technology for Construction of China in Mountainous Area, Chongqing University, Chongqing 400030, China;
3. Changjiang Institute of Survey Planning Design and Research, Changjiang Water Resources Commission, Wuhan Hubei 430072, China
Abstract This study used FLAC to simulate the excavation of unsymmetrical loaded tunnels with various transversal gradients, surrounding rock grades, and thicknesses of side covering soil by considering all factors that affect these unsymmetrical loaded tunnels. The deformation behavior and displacements of key points were analyzed. The effects of unsymmetrical loading are negligible when the thickness of the side covering soil exceeds 21 m, and pre-reinforcement is needed prior to excavation when the thickness of the side covering soil is less than 15 m. These data were used in simulating tunnel pre-reinforcement in different conditions. Results indicate that in the condition of surrounding rocks V, a main problem is insufficient counter pressure in the shallow buried side when the thickness of the side covering soil is less than 7 m. By contrast, overpressure in the deep buried side needs to be addressed when the thickness of the side covering soil is more than 7 m. These findings were verified in actual practice. The conclusions of this study can be used as references to design and construct similar engineering projects.
Fund:Supported by the National Natural Science Foundation of China (No.41172243);the China Postdoctoral Science Foundation (No.201003315);and the Program for Changjiang Scholars and Innovative Research Team in University (No.IRT1045)
Corresponding Authors:
YANG Chao, vanni1010@yahoo.com.cn
E-mail: vanni1010@yahoo.com.cn
YANG Chao,ZHANG Yong-xing,HUANG Da, et al. Deformation Behavior of Topographic Unsymmetrical Loaded Tunnels and Their Pre-reinforcements after Excavation[J]. Journal of Highway and Transportation Research and Development, 2013, 7(3): 69-75.
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2013, Vol. 7 
