软弱缓倾层状岩层隧道围岩结构变形与失稳机制试验研究  

The deformation and unstability mechanism of surrounding rock of tunnel in the soft and gently dipping layered strata

作　　者：李元海[1,2] 赵万勇 朱茂国 刘德柱 于恒 LI Yuanhai;ZHAO Wanyong;ZHU Maoguo;LIU Dezhu;YU Heng(State Key Laboratory of Intelligent Construction and Healthy Operation&Maintenance of Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;China Railway Liuyuan Group Co,Tianjin 300308,China)

机构地区：[1]中国矿业大学深地工程智能建造与健康运维全国重点实验室,江苏徐州221116 [2]中国矿业大学力学与土木工程学院,江苏徐州221116 [3]中铁第六勘察设计院集团有限公司,天津300308

出　　处：《采矿与安全工程学报》2024年第6期1148-1157,共10页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(52274141);国家重点研发计划项目(2022YFC3003304)。

摘　　要：为探究软弱缓倾层状岩层隧道围岩结构变形与失稳机制,通过大比例相似模型试验,采用自主开发的岩土计算机视觉量测系统PhotoInfor进行围岩变形时空演变过程观测分析,并通过建立围岩结构力学模型探讨围岩失稳机制。研究结果表明:软弱缓倾层状隧道围岩变形的空间分布特征是首先在拱顶处产生裂纹,随着围岩荷载增加,左右拱肩出现垂直于层理面方向的裂纹并与层理面及拱顶裂纹贯通,进而形成剪切楔并最终塌落导致围岩失稳;缓倾层状岩体存在顺层偏压现象,在荷载作用下围岩结构变形明显左右不对称,在时间演变特征上表现为经历顶板断裂、拱肩失稳和隧道坍塌3个阶段;根据试验现象观测,提出可将隧道围岩顶板与拱肩岩层处分别简化为受均布荷载的简支梁、悬臂梁和受非均布荷载的简支梁力学模型,以此揭示了软弱缓倾层状隧道的围岩结构变形与失稳机制。In order to explore deformation and instability mechanism of surrounding rock structure of tunnel in gently dipping layered soft rock,a large-scale similar model test was conducted,and the self-developed computer vision measurement system PhotoInfor was used to observe and analyze the spatiotemporal evolution process of the surrounding rock deformation,and instability mechanism of surrounding rock was discussed by established a mechanical model of the surrounding rock structure.The results show that the spatial distribution characteristics of surrounding rock deformation of tunnel in gently dipping layered soft rocks show initial crack formation at the vault.With the load of surrounding rock increases,cracks appear in the left and right spandrels perpendicular to the bedding plane and connect with the bedding plane and vault cracks,leading to the formation of shear wedges and eventually slumping,causing surrounding rock instability.The gently dipping layered rock mass exhibits bedding lateral pressure,and the deformation of surrounding rock structure is clearly left-right asymmetrical under load.In terms of time evolution characteristics,it goes through three stages:roof fracture,spandrel instability and tunnel collapse.According to the experimental observation,at roof strata and spandrels strata,the surrounding rock structure of tunnel can be simplified into the mechanical model of simply supported beam under uniform load,cantilever beam and simply supported beam under heterogeneous load,respectively,which reveals the deformation and instability mechanism of surrounding rock structure of tunnel in gently dipping layered soft rock.

关 键 词：隧道工程 层状岩层 围岩结构 模型试验 力学模型 

分 类 号：U451[建筑科学—桥梁与隧道工程]