Seismic Response Of Loess Tunnel Under The Coupling Action Of Rain Seepage And Vehicle

With the western development as well as the further promotion and implementation of the Twelfth Five-Year Guideline and other important strategies, the construction of highway tunnel is developing at high speed. The traffic network has extended to the high mountains and deep water area nearshore. The rapid development of the traffic network in the west has become a platform of the western economy. The traffic network in the west has become the link among the coastal cities in the developed areas. It will contribute to strengthening the economic and cultural exchanges between the west and the outside world. The total amount and construction scale will increase because of the importance of highway tunnel. But it is difficult to construct and maintain the tunnel in the west region whose large area is covered by loess. The main reason is based on the undesirable characteristics of loess, the special topography, hydrology, climate environment and other complex conditions in the western region of China, all above these will result in loess tunnel collapse, lining crack,leakage of water and other engineering diseases all of which endanger traffic and personal safety.This paper analyzes the curved wall section loess tunnel considering the influence of weight, earthquake, vehicle, rain water seepage and other factors. Vehicle dynamic model, structural field model and fluid field model are established by using ADINA. The coupling interaction of the rain water seepage and the vehicle load under three kinds of conditions which includes near field pulse, no pulse near field and far field earthquake. The change law of stress, strain, displacement, pore water pressure,etc. of loess tunnel structure under different buried depth, different rainfall and other factors is analyzed quantitatively. In this paper, following aspects of the works have been done:(1) The coupling effect of vehicle load and seismic dynamic load in loess tunnel structure is studied. Two-dimensional finite element model of vehicle dynamic structure is established under viscoelastic boundary by using ADINA. Vehicle loads are calculated by using MATLAB. The coupling effect of loess tunnel structure under the action of near field pulse earthquake, no pulse near field earthquake and the far field earthquake with vehicle load. The coupling effect of loess tunnel under different buried depth with near field pulse earthquake action and vehicle load is studied. The change law of displacement and stress in loess tunnel structure is obtained.(2) Two-dimensional finite element rain water seepage and structure field calculation model are established under viscoelastic boundary by using ADINA.Coupling solution of two models is done by using FSI. The change law of stress,strain, etc. of curved wall section loess tunnel structure with 30 m buried depth is studied under different earthquake and different rainfall.The loess tunnel structure with 140 mm rainfall is studied under near field pulse earthquake and different buried depths. The law of lining deformation of loess tunnel structure is obtained under the action of complicated load coupling.(3) The coupling effect of loess tunnel structure under the action of rain water seepage, vehicle load and seismic dynamic is studied. Two-dimensional finite element vehicle dynamic structure and rain water seepage calculation model are established under viscoelastic boundary by using ADINA. Coupling solution of two models is done by using FSI. The change law of stress, strain, displacement, pore water pressure,etc. of loess tunnel structure under near field pulse earthquake, different rainfall and different buried depth is studied. The law of lining deformation of loess tunnel structure is obtained under the action of complicated load coupling.By analyzing the stress, strain, displacement of loess tunnel structure with 30 m buried depth under different seismic dynamic and vehicle load, it is found that the influence of near field pulse earthquake on structure is the largest. The coupling effect of loess tunnel structure with different buried depths is studied under near field pulse earthquake and vehicle load. The stress, strain, displacement and acceleration of the loess tunnel show an increasing trend with the increase of buried depth. The coupling effect of curved wall section loess tunnel structure with 30 m buried depth is studied under different seismic dynamic and rain water seepage. The results indicate that the stress, pore water pressure etc. show an increasing trend with the increase of rainfall.The pore water pressure of the nodes around the tunnel shows an increasing trend with the increase of buried depth under the action of near field pulse when rainfall is140 mm. The coupling effect of loess tunnel structure with different rainfall is studied under near field pulse earthquake and vehicle load. The stress, displacement and pore water pressure of the loess tunnel show an increasing trend with the increase of rainfall.