Laboratory Model Tests and DEM Simulations of Unloading-Induced Tunnel Failure Mechanism

作     者：Abierdi Yuzhou Xiang Haiyi Zhong Xin Gu Hanlong Liu Wengang Zhang 

作者机构：School of HehaiChongqing Jiaotong UniversityChongqing400074China School of Civil EngineeringChongqing UniversityChongqing400045China Key Laboratory of New Technology for Construction of Cities in Mountain AreaChongqing UniversityChongqing400045China 

出 版 物：《Computers, Materials & Continua》 (计算机、材料和连续体（英文）)

年 卷 期：2020年第63卷第5期

页      面：825-844页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：the support by the National Natural Science Foundation of China(No.51608071) Natural Science Foundation of Chongqing,China(cstc2018jcyjAX0632) General Financial Grant from the China Postdoctoral Science Foundation(Grant No.2017M620414) the Special Funding for Post-doctoral Researchers in Chongqing(No.Xm2017007) 

主　　题：Tunnel unloading model testing particle flow model force chain 

摘      要：Tunnel excavation is a complicated loading-unloading-reloading process characterized by decreased radial stresses and increased axial *** approach that considers only loading,is generally used in tunnel model ***,this approach is incapable of characterizing the unloading effects induced by excavation on surrounding rocks and hence presents radial and tangential stress paths during the failure process that are different from the actual stress state of *** paper carried out a comparative analysis using laboratory model testing and particle flow code(PFC2D)-based numerical simulation,and shed light upon the crack propagation process and,microscopic stress and force chain variations during the loading-unloading *** failure mode observed in the unloading model test is shear *** force chains are strongly correlated with the concrete fracture *** addition,the change patterns of the radial and tangential stresses of surrounding rocks in the broken region,as well as the influence of the initial stress on failure loads are *** surrounding soil of tunnel failure evolution as well as extent and shape of the damage zone during the excavation-induced unloading were also studied.