Numerical Simulation Of Tunnel Surrounding Rock Stability At Fault Zone

Faults in the underground engineering result in lots of mechanical and geological troubles, bringing rock mass instability and geological hazard at times. However, faults problems, especially the deformation and damage effect of fractured zone of tunnels, do not have been studied and solved by mechanical methods; and the special toppling deformation and mechanisms of the surrounding rock stability of tunnel with fault zones have not been researched systematically and professionally.This paper takes the Huan Shan ping tunnel of round-the-city expressway in Chongqing city as example, to discuss and study the surrounding rock stability affected by fault. The main achievements are presented as follows:â‘ Based on the research of surrounding rock stability by predecessors, the stress distribution, the influencing factors and criterions of surrounding rock stability during the tunnel excavation and supporting processes,and the surrounding rock stability in self-weight stress field have been analyzed. It can provide a technical guarantee and prophase preparation for tunnel excavation and monitoring.â‘¡The mechanical behavior of tunnel excavation and support based on FLAC3D are simulated and studied, the distributing law of displacement, stress and strain in rock mass during the tunnel construction have bee analyzed, to puts forward stress-strain response characteristics, making great sense of guiding instruction and advice in engineering for evaluation of stability and security in surrounding rock during tunnel construction.â‘¢By founding the three dimensional finite difference simulating program based on FLAC3D , the affected distance of fault fracture zone is analyzed. Then, three-dimensional finite element method is used to analyze systematically the distribution of stress and strain field in the surrounding rock mass of the underground cavities after excavation. Finally, deformation and failure of surrounding rock have been affected close to the fault in the process of excavation and supporting.â‘£Compared with the value of excavation and support without fault, it can be concluded that fault affects the continuity of stress distribution to a certain extent, and the displacement and horizontal convergence of the vault is much larger, bringing some impacts to the construction and monitoring .Study on the stability of tunnel surrounding rock affected by fault is of great practical significance to optimize design parameter and to advance construction quality.