Study On Cumulative Dynamic Damage Mechanism Of High-Speed Railway Tunnels

With the development of high-speed railway construction in our country,the problem of long-term dynamic stability of high-speed railway tunnel has been paid more and more attention in engineering and academe.It is very important to study the dynamic response characteristics and cumulative damage law of the lining structure of tunnel under the dynamic loadings of high-speed train.In this thesis,the Jinshazhou tunnel of the high-speed railway from Wuhan to Guangzhou is taken as the research object,and supported by the project of National Natural Science Foundation of China(No:51278121),the mechanism of dynamic cumulative damage and fatigue life of the lining structure of high speed railway's tunnel are analyzed under high speed train loadings,by means of theoretical analysis,finite element simulation and model test.The main research contents and results are as follows:(1)The plastic damage constitutive models of Lee-Fenves and Guo-Zhang are introduced into analysis of dynamic cumulative damage for the lining structure of high speed railway's tunnel.And based on the software of ABAQUS about the nonlinear dynamic finite element,the program model is developed for the plastic damage constitutive model of concrete.(2)By using the research results on the vibration loadings of high-speed train and the vehicle design parameters of high speed train,a method of dynamic analysis is established,which can be used to analyze the superposition effect of moving loadings of train,and based on the software of ABAQUS,the subroutine is developed to simulate the moving load of high-speed train.(3)By introducing the boundary conditions of infinite elements,the FEM of dynamic is established to used to analyze the interaction between the tunnel and surrounding rock of high speed railway.And based on the plastic damage constitutive model of concrete,the dynamic damage characteristics about the lining structure of high-speed railway's tunnel are studied under the vibration loadings of high speed train.And then,the dynamic cumulative damage law about the lining structure of high-speed railway tunnel is obtained and the fatigue life of the lining structure is analyzed.(4)Based on the principle of similar material model test and the experimental results of micro-concrete,the whole section test model of high speed railway's tunnel is constructed.and based on the hydraulic servo loading system of MTS,a set of conversion device for dynamic loading is designed out.(5)The vibration load of high speed train is applied to the whole section test model of tunnel,and so as to carry out the test of dynamic cumulative damage for the lining structure of high-speed railway's tunnel.And then,the law of dynamic cumulative damage about the lining structure of tunnel is obtained.Finally,compared with the results of model test and finite element simulation,the research conclusion is proved to be reasonable.The research results of this thesis has important theoretical and engineering application value for perfecting the theory of long term dynamic stability analysis for high-speed railway's tunnel and improving the design and operation management level of high-speed railway in china.