Research On The Influence Of Geological Defects On Earthquake Damage Of Deep Underground Engineering

Earthquake,which is a serious threat to human life and property safety,is one of the natural disasters?The "5.12 " Wenchuan Earthquake extremely rare earthquake in the Chinese history, the earthquake caused seriously casualties and property loss. This article summarized the domestic and foreign representative instances of tunnel damage?damage types?characteristics and the present situation and method of tunnel and underground engineering seismic research, then, by finite element numerical simulation simulated the influence of geological structure defects, such as fault and fracture zone, on tunnel lining and simulated the vibration isolation effect of isolation layer which was set in the fracture zone between The surrounding rock and lining.The underground engineering that this paper studies is located in the Longmen Mountain Fault Zone, and in the Wenchuan earthquake zone, which was seriously damaged in the 5.12 Wenchuan earthquake. Therefore, with Dr. pan's guidance, the research team went to the project location of Chengdu to investigate several times, and we made numerical simulation analysis on this project.At first, this paper expounded the research status of underground engineering and geological defects, and then in the second chapter made a systematic exposition of the finite element theory related to the research. The third chapter introduced the project background, mainly about regional tectonic environment, the Longmen Mountain fault at the project and some background information of the 5.12 Wenchuan earthquake is introduced. The fourth chapter introduces the modeling process with the finite element analysis software of MIDAS/GTS. The fifth chapter is the analyze of the calculated results, then draw a conclusion.Secondly combining actual engineering, by way of applying displacement field to simulate the dislocation of fault zone (which means F1 fault) and the way to set weak layer to simulate the secondary fracture zone and between the lining and surrounding rock foam concrete isolation layer was set up.By the numerical simulation of the effect of fracture zone and isolation layer on the project, we can draw the conclusion concluded that the fracture zone increased the maximum displacement of the structure, and makes the structure local large deformation displacement mutation and stress concentration, but at the same time, fracture zone has a certain energy damping effect, after the displacement mutation of structure displacement will be reduced. The isolation layer between fracture zone and the lining can relieve stress concentration, and it does not change the rest of the structure stress a great many, at the same time the maximum displacement of the structure basically stayed the same.Finally, this paper summarized some problems and the insufficiencies in the research, put forward the direction of further research and the problems need to be solved. With the far-reaching practical significance of underground engineering seismic research, hope that the follow-up research work further to get effective seismic shock absorption measures of underground projects, and that can be more powerful to protect people's lives and property.