标题：Numerical investigation on the stability of deforming fractured rocks using discrete fracture networks: a case study of underground excavation
作者：Wang, Luyu; Chen, Weizhong; Tan, Xuyan; Tan, Xianjun; Yang, Jianping; Yang, Diansen; Zhang, Xi
作者机构：[Wang, Luyu; Chen, Weizhong; Tan, Xuyan; Tan, Xianjun; Yang, Jianping; Yang, Diansen] Chinese Acad Sci, State Key Lab Geomech & Geotech Engn, Inst Roc 更多
通讯作者：Chen, Weizhong;Chen, WZ;Chen, WZ
通讯作者地址：[Chen, WZ]Chinese Acad Sci, State Key Lab Geomech & Geotech Engn, Inst Rock & Soil Mech, Wuhan 430071, Peoples R China;[Chen, WZ]Shandong Univ, Res Ct 更多
来源：BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
关键词：Fractured rocks; Discrete fractures; Underground excavation; Stability; analysis; Hybrid finite element method
摘要：The stability of a fractured rock mass around a subsurface opening is critical to tunnel excavation. The traditional underground excavation analysis is based on a continuum description of randomly distributed discrete pre-existing fractures. In contrast to this, we have developed an improved hybrid finite element method (FEM) to investigate the stability of fractured rocks around an excavation by incorporating the outputs into the FEM codes. The proposed model consists of a discrete fracture network (DFN) model and cohesive zone model (CZM). The DFN model automatically generates a fracture network with a given fracture opening distribution and provides grid generation strategy to the FEM. The CZM captures material failure and intersection and surface contacts through the fracture element with different constitutive laws. As a case study, a DFN model was formulated for the underground excavation at Jinping Hydropower Station, in light of the input requirements of our model, and its deformation analysis was performed. The comparison analysis of rock deformation was made for excavation in both intact rock mass and fractured rock mass under the same boundary conditions. The numerical results show that two different modes of rock failure exist in these two rock masses and that intense deformation at the fractures intersected by the tunnel is responsible for fractured rock mass instability. The proposed approach was verified using data from field investigations. A larger displacement can be produced if the rock mass is weakened by a key block. A sensitivity analysis was carried out to investigate the effects of different model parameters on deformation variations. This study provides an insightful understanding of the deformation of fractured rock mass during tunnel excavation.