Random Response Analysis Of Underwater Shield Tunnel Subjected To Earthquake

The convenience of transportation has a direct effect on the development of urban economy.In recent years,the saturation of the traffic on the ground is becoming more and more obvious,the development and utilization of underground space is particularly urgent.However,China has a special geographical position,most of the region is in a high incidence area of earthquake,so it is very important to study how to ensure the normal work of the underground structure in the earthquake.The research of this paper is based on the tunnel project in the National 973 Qiongzhou Strait Project,introducing the concept of cycle substructure to shield tunnel longitudinal seismic design and combining with the pseudo-excitation method,to do the seismic response and reliability analysis.This paper has done the following works.First of all,full investigation of the research method of tunnel structure and seismic had been done,then the seismic data of the tunnel,systematic and detailed stating the failure form,damage status and mechanism,influencing factors and development trend of tunnel damage were arranged.Secondly,fully studied the wave propagation theory of random vibration response analysis of applicability analysis problem for longitudinal seismic long span tunnel,established the longitudinal seismic response of shield tunnel model analysis,applied harmonic load under different excitation direction.Through the period of sub structure method of pseudo excitation method,the spectrum and displacement response variance were get.The seismic behavior of shield tunnel under different geological conditions was analyzed.In addition,the response of shield tunnel under non-stationary excitation was researched.Then this article discussed the variance trend of structure under different viscous damping,different section number.Thirdly,the virtual excitation method was used to analyze the single degree of freedom system in ANSYS and MATLAB respectively.So the feasibility of the virtual excitation method was verified in ANSYS.Furthermore,the seismic response of tunnel cross-section was analyzed in ANSYS,and the displacement and stress spectrum of tunnel were obtained.The reliability analysis of lining was carried by using the reliability calculation formula of Davenport.Finally,by using the dynamic time history method and ANSYS command stream,a finite element model of cross section of shield tunnel was modeled.Then the EL-CENTRO seismic wave was applied to the model to analyze the internal force variation law of shield tunnel lining structure,discussed the internal force variation of tunnel lining structure under different buried depth,different lining types,different lining thickness and several parallel tunnels.