顶部隐伏溶洞对深埋隧道围岩稳定性影响的离散元数值研究  

Discrete element numerical study on the influence of hidden karst cave on the stability of surrounding rock of deep tunnel

作　　者：张晓景 雷晓丹 ZHANG Xiao-jing;LEI Xiao-dan(The Communication Planning Surveying and Designing Institute of Shanxi Province,Taiyuan 030012,Shanxi,China;Department of Architecture and Civil Engineering,Taiyuan University,Taiyuan 030032,Shanxi,China)

机构地区：[1]山西省交通规划勘察设计院有限公司,山西太原030032 [2]太原学院建筑工程系,山西太原030032

出　　处：《黑龙江交通科技》2020年第10期119-121,123,共4页Communications Science and Technology Heilongjiang

摘　　要：我国西南地区岩溶区的广泛分布大大增加了隧道设计施工及后期运营的难度和风险。为研究顶部隐伏溶洞对隧道围岩稳定性的影响,通过构建PFC2D离散元数值模型,对无溶洞环境和顶部溶洞环境隧道开挖过程中围岩变形及破坏的最终形态进行了对比研究,并剖析了顶部溶洞环境下围岩破坏的演化过程。结果表明:顶部溶洞的存在对隧道围岩位移场分布有明显影响,溶洞引起的围岩位移场和隧道开挖引起的围岩位移场整体向外扩散,围岩变形的范围较无溶洞环境明显扩大。隧道和溶洞间的围岩受力复杂,容易产生应力集中,导致隧道围岩坍塌。隧道开挖后,裂纹首先出现在溶洞底部和隧道拱顶,后逐渐向中间发展,发展为“X”形裂纹,最终贯通,围岩发生压剪破坏。The wide distribution of karst areas in Southwest China greatly increases the difficulty and risk of tunnel design and construction and later operation.The PFC2D discrete element numerical models are constructed to study the influence of the top hidden karst cave on the stability of the surrounding rock of the tunnel.The final shape of the deformation and failure of the surrounding rock in the environment of no karst cave and top karst cave are compared,and the evolution process of the failure in the top karst cave environment is analyzed.The results show that the existence of the top karst cave has a significant impact on the distribution of the displacement field of the surrounding rock of the tunnel.The displacement field of the surrounding rock caused by the karst cave and the excavation of the tunnel all spread out,and the scope of the deformation of the surrounding rock is significantly expanded compared with the no karst cave environment.The stress of the surrounding rock between the tunnel and the karst cave are complex,which is easy to produce stress concentration,leading to the collapse of the surrounding rock.After the excavation of the tunnel,the cracks appear at the bottom of the cave and the vault of the tunnel firstly,and then gradually develop to the middle,developing into"X"shaped cracks,and finally forming through cracks,resulting in the compression shear failure of surrounding rock.

关 键 词：顶部溶洞 位移场 压剪破坏 

分 类 号：U433[交通运输工程—道路与铁道工程]