Analysis Of Seismic Dynamic Response Of Subway Shield Tunnel

With the rapid development of urban traffic,underground rail transit has become the fundamental ways to solve large and medium-sized cities and urban transportation,it is great significance for the urban sustainable development of the 21 st century.China is a multi-earthquake country.After the Wenchuan earthquake,a large number of underground structures were severely damaged.Large-scale rail transit construction will inevitably result in the combination of the underground structure of subway and the combination of spatial structure.The increasingly complex underground structure of underground railway has put forward higher requirements for the seismic performance of metro rail transit.Therefore,it is necessary to analyze the seismic response of subway shield tunnel under different combinations.This paper systematically studies the seismic performance of complex subway tunnels,such as near underground parallel tunneling and cross tunneling in urban subway tunnels,Based on the basic principles of seismic response analysis of underground structures,the earthquake damage mechanism of underground structures is summarized.Based on the theory of viscoelastic artificial boundary and dynamic finite element theory of underground structure,the seismic response characteristics of subway tunnel are discussed.In this paper,the dynamic response analysis of double-hole parallel tunnel,cross tunnel and spatial combination tunnel is studied.The specific research content is as follows:(1)Comprehensively explain the research background and research status,summarize the characteristics of seismic damage of underground structures,analyze and clarify the seismic analysis methods and calculation procedures of existing underground structures,and compare the advantages of various methods.The shortcomings and applicability provide a theoretical basis for the design of underground structures.(2)Based on the theory of viscoelastic artificial boundary and the input method of exogenous waves,the plane interior method is derived to the artificial boundary,the plane internal tangent to the artificial boundary and the plane to the artificial boundary.Based on the viscoelastic artificial boundary and wave input method,vertical incident plane p waves is deduced the calculation formula of equivalent load,viscoelastic artificial boundary is verified by numerical examples and the precision and accuracy of the ground motion input.(3)The system introduces the basic theory of dynamic finite element,including soil dynamic constitutive relation,the establishment of dynamic finite element equation and solving,soil-structure dynamic interaction,the selection of seismic wave,for subway shield tunnel structure thus laid a foundation for the numerical analysis of earthquake response.(4)Based on the theory of viscoelastic artificial boundary,the seismic dynamic response of subway tunnel is studied by numerical simulation.Under the seismic p wave vertical incidence,according to different channel spacing,different tunnel embedment depth,different lining stiffness and different earthquake intensity of double hole systematically research on seismic response of the tunnel structure.(5)Using ADINA to establish a finite element model for tunnels with different combinations.Seismic dynamic response analysis of subway tunnels with different spacings and seismic response analysis of two-line parallel tunnels with different combinations are studied,and the dynamic characteristics of the subway underground complex combination structure regularity systematically summarized.This paper studies the seismic response of subway shield tunnel,and obtains the general rule of shield tunnel structure under earthquake excitation,which can provide reference for the seismic design of shield tunnel structure.