Time-history Analysis On Seismic Absorbing And Isolating Performance Of The Lining For A Highway Tunnel

With the rapid development of our country transportation enterprise,highway tunnel seismic performance in seismic region get more attention of people.In addition to relying on tunnel its structural material performance.It is an important way to use all kinds of reducing vibration isolation technology measures to improve the seismic performance of modern tunnel of promoting the progress of science and technology of tunnel engineering,the scientific and reasonable evaluation of the technical measures,which has great realistic significance for practical engineering.This dissertation rely on a highway tunnel project in the east of guangdong area as the research object,based on the finite element analysis method of tunnel engineering,using material elastoplastic constitutive relation,aiming at the mouth of the shallow buried and fault zone to build three-dimensional finite element model,considering the basis of a variety of analyzing the working condition of the seismic response time history analysis,obtained the corresponding research results,main research contents and results of this article are as follows:(1)On the basis of summary of earthquake damage,principle and design method of tunnel engineering in China and abroad,seismic analysis,,discusses the tunnel engineering seismic isolation technique and its characteristics;Based on the finite element method of tunnel engineering,in the use of materials elastic-plastic constitutive relation,aiming at the mouth of the shallow buried sets up a three-dimensional finite element analysis model,which takes into account the reduction of isolation layer and different material mechanics parameters,etc.,to carry out in this dissertation,based on engineering seismic response analysis provides the basis.(2)Uing the finite element model and tunnel engineering finite element analysis software MIDAS/GTS,by entering a horizontal and vertical seismic time history analysis,in view of the object in this dissertation,we study the seismic performance of and reduce isolation characteristics are studied,isolation material properties and different isolation layer thickness compares the effects on seismic response of the lining of calculation and analysis,the reasonable isolation materials and relatively reasonable isolation layer thickness.(3)Tnnel lining system which never set the isolation layer of seismic response time history analysis results can be seen that the hole location of the lining of the deformation and stress results is larger,with the increase of tunnel buried depth,the deformation and stress relative decline,description of tunnel lining has a certain seismic capacity,the seismic fortification location should focus on the mouth of the cave.When setting isolation layer,under horizontal seismic action and the vertical seismic action,the displacement and acceleration distribution of tunnel lining has no obvious change,but the normal stress,Mises stress and maximum shear stress are significantly reduced,it set the isolation layer is a very effective tunnel damping technical measures.(4)The analysis results show that no matter reduce isolation layer material elastic modulus,or increase the thickness of the isolation layer,can significantly reduce the lining of the seismic stress level;In terms of the research object in this dissertation,it is most good to selecting isolation layer thickness of 20 cm of damping control of the tunnel.This article research results can be used for reference in the practical engineering.