【作者】 徐前卫； 朱合华； 丁文其； 李志厚； 罗云； 朱道建；

【Author】 Xu Qianwei;Zhu Hehua;Ding Wenqi;Li Zhihou;Luo Yun;Zhu Daojian;Key Laboratory of Road and Traffic Engineering of the State Ministry of Education,Tongji University;Key Laboratory of Geotechnical and Underground Engineering,Ministry of Education,Tongji University;Yunnan Broadvision Engineering Consultants;Shenzhen Traffic Utilities Construction Center;Shanghai Municipal Engineering Design Institute Group Co.Ltd.;

【机构】 同济大学道路与交通工程教育部重点实验室； 同济大学岩土及地下工程教育部重点实验室； 云南省交通规划设计研究院； 深圳市交通公用设施建设中心； 上海市政工程设计研究总院(集团)有限公司；

【摘要】 在软弱围岩中进行隧道开挖,往往因岩体变形过分或局部应力集中而导致围岩失稳破坏,在实际工程中大多采用锚杆作早期支护。文章以Ⅳ级软弱围岩为参照对象,利用相似模型试验进行了锚杆支护条件下的隧道施工过程模拟,对开挖过程中围岩的渐进破坏特征、破坏模式以及锚杆的支护效应进行了研究。试验结果表明,隧道开挖将会在隧道周边形成一应力扰动区,而真正塌落成拱的只是该扰动区的一部分;由于有锚杆的支承作用,拱顶岩体的破坏呈分区破坏模式;岩体的破坏范围主要集中在隧道两侧与水平面成45°+φ/2的扇形区域内;在隧道开挖后,拱顶上方岩体的切向应力升高形成承载压力拱,主要位于距拱顶约1.0~1.25B处(B为隧道跨度)。更多还原

【Abstract】 Instability and even failure of surrounding rock are often caused by excessive rock deformation or local stress concentration when tunneling in soft surrounding rocks,and the anchor bolt is mainly used in practical engineering for initial support.Based on soft surrounding rock of grade Ⅳ,tunnel construction with bolt support was simulated by a similarity model test,and the progressive failure feature,failure mode of the surrounding rock,and supporting effects of an anchor bolt were studied.The results show that a stress disturbance area will be formed around the tunnel by excavation,but only a part of the disturbance area really will be damaged.Because of the support of the anchor bolt,rock damage on the crown presents a partitional failure mode,and the failure area of the rock is mainly concentrated in the sector formed by two tunnel sides with an angle of 45° +(?)/2 to the horizontal plane.After excavation,a pressure-bearing arch,which is mainly located approximately 1.0-1.25B(B= tunnel span) away from the crown,is formed with increasing tangential stress of the rock mass above the crown.更多还原