(1. Key Laboratory of Road and Traffic Engineering of Ministry of Education，Tongji University，Shanghai 201804，China；2. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education，Tongji University，Shanghai 200092，China；3. The Second Engineering Co.，Ltd. of China Railway Seventh Group，Xian，Shaanxi 710032，China)
Abstract：In order to study the failure characteristics of weak rock mass and the anchoring effect of rock bolts，a series of geomechanical model experiments were carried out to simulate tunnel excavation in rock mass of grade Ⅳ，which includes two modes，unsupported and supported with bolts. Subsequently，the evaluation laws of displacement，stress and the macroscopic failure forms of the surrounding rock mass were analyzed through a comprehensive comparison. According to the experiment results，the following conclusions can be drawn. (1)The damage of surrounding rock induced by tunnel excavation starts from tunnel arch foot，extending upwards gradually and collapsing into arch eventually. (2) Due to the anchor suspension and extrusion effect of bolts combined with the rock beam effect，the rock collapse zone can be reduced significantly. (3) The bolts can improve the strength and toughness of rock mass owning to the applied anchor force，which is conducive to enhance the bearing capacity and the deformation resistance ability of surrounding rock. (4) The bolts can make the surrounding rock obtain a stable equilibrium with high energy，which not only makes the stress distribution in rock mass more balanced，but also delays the rock entering into the “softening” stage. The conclusions gained can provide references for the stability evaluation of soft rock mass during tunnel construction as well as the design and construction of the supporting structures.
程盼盼1，徐前卫1，朱合华2，丁文其2，陈国中3，吴永波3. 软弱隧道围岩拱顶塌方及锚杆支护效应试验研究[J]. 岩石力学与工程学报, 2016, 35(S2): 3561-3569.
CHENG Panpan1，XU Qianwei1，ZHU Hehua2，DING Wenqi2，CHEN Guozhong3，WU Yongbo3. Model experiment study on the failure characteristics of weak surrounding rock mass above tunnel arch and the anchoring effect of bolts. , 2016, 35(S2): 3561-3569.
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2016, Vol. 35 
