超载作用下浅埋硬岩隧洞破坏模式模型试验研究  

Study on Model Test of Shallow Hard-rock Tunnel Failure Mode by the Action of Overload

作　　者：刘泉维 蔺文豪 李为腾[1] 秦哲[1] 冯强[1] 杨旭旭 LIU Quanwei;LIN Wenhao;LI Weiteng;QIN Zhe;FENG Qiang;YANG Xuxu(Shandong University of Science and Technology,Qingdao 266000;Qingdao Metro Line 6 Co.,Ltd.,Qingdao 266000)

机构地区：[1]山东科技大学,青岛266000 [2]青岛市地铁六号线有限公司,青岛266000

出　　处：《现代隧道技术》2022年第6期125-131,161,共8页Modern Tunnelling Technology

摘　　要：为研究超载作用下浅埋硬岩隧洞的破坏模式,依托青岛地铁6号线青医西院区站QY-7+177监测断面开展大型相似模型试验研究,以容重、抗压强度、抗拉强度、内摩擦角为材料主控参数真实还原模拟断面岩体的物理力学特性,采用非接触式应变测量系统观测裂隙演化过程。超载过程中隧洞围岩拱部出现一系列与拱顶法线夹角在25°~40°之间的正“八”字型剪切破坏裂隙,结合格里菲斯强度准则计算最先出现在拱顶正上方裂隙的起裂最大主应力为0.409 MPa,为相似材料单轴抗压强度的21.6%。试验结果表明,隧洞围岩拱顶上方在较低应力水平下已开始出现裂隙,为围岩的起裂危险区。隧洞围岩的破坏形式为拱部剪切破坏和拱脚处岩体破碎挤出破坏相耦合的剪切-挤出破坏模式。To research the failure mode of the shallow hard-rock tunnel by the action of overload, the study on a large similar model test is conducted on the basis of QY-7+177 monitoring section of The Affiliated Hospital of Qingdao University West Coast District Station of Qingdao Metro Line 6. Unit weight, compressive strength, tensile strength and angle of internal friction are used as the main control parameters of the material to truly reproduce and simulate the physical and mechanical properties of cross-sectional rock mass, and the non-contact strain measurement system is used to observe the process of fissure evolution. A series of inverted V-shaped shear fissures with an included angle of 25°~40° with the crown normal appears during the process of overload, and combined with the Griffith theory of brittle strength, the maximum principal initiation stress of the fissure that first appeared directly above the vault is calculated to be 0.409 MPa, which is 21.6% of the uniaxial compressive strength of similar materials.Test results show that fissures begin to appear on the crown of the surrounding rock of the tunnel even if the stress is relatively low, indicating that it is a hazardous area prone to fissure initiation of the surrounding rock. The failure mode of the surrounding rock of the tunnel is the shear-extrusion failure mode: the arch is subject to shear failure and the rock mass is broken and extruded at the foot of the arch to damage phase coupling.

关 键 词：浅埋硬岩隧洞 超载试验 裂隙演化 破坏模式 

分 类 号：TU91[建筑科学—建筑理论] U451[建筑科学—桥梁与隧道工程]