Study On Coupling Dynamic Response And Failure Mechanism Of Embankment And Abutment Under Strong Earthquake

China is an earthquake-prone country. The earthquakes bring about the serious destruction for transportation infrastructure, resulting in significant economic loss. Meanwhile, it seriously affects the disaster relief. The transition of embankment and bridge, one of the weakest section, is often subjected to serious damage during quake, and it is characterized by the permanent displacement most significantly. To explored failure mechanism and dynamic response law of embankment and abutment under the action of earthquake, the studies including its dynamic analysis, the calculation theory of abutment's displacement, and seismic design are conducted by using the methods of field investigation, theory and simulation. The conclusions are obtained as follows.Firstly, the damage features and failure mechanism are preliminarily presented. Based on the field investigation method after the earthquake, the failure types of embankment and abutment and their failure mechanisms are preliminarily investigated. The failure types are summed up as follow, dislocation induced by uneven subsidence of embankment, longitudinal and lateral crack, uplift, collapse, unstability of slope, movement of abutment, inclination, lateral displacement, shear crack of abutment, diagonal cracks, breakdown of abutment. It is meaningful to supply the researchers with important datas.Secondly, the calculation model of displacement is established, which could reflect the failure features of soil-abutment. Meanwhile, the calculation theory of displacement considering the strength degradation of soil is preliminarily presented. Based on the analysis of failural characteristiscs of soil-abutment from the field investigation, thesimplified failure mode is presented. Then, combined the dynamic response analysis with Newmark finite sliding block method, the coupling calculation method is presented, which could simplify the calculation. Therefore, it is easy to be appl ied to practice.Thirdly, the 3D-dimension coupling dynamic model of soil-abutment is established by using the simulation method, and dynamic response law and its influence factors of soil-abutment are investigated.Considering the nonlinear and strength degradation of soil and the sliding and rotation of abutment, the the 3D-dimension coupling dynamic model is established. The dynamic responses, including the distribution of dynamic stress and deformation, variation law of abutment displacement with strength of ground motion, are conducted. Then, the relationships of abutment displacement between the strength of ground motion and height of abutment and the amplification effect are obtained in this paper. It is helpful to establish the calculation theoty of abutment displacement.Fourthly, the seismic design based on the displacement is preliminarily presented adopting the calculation theoty presented in this paper.The displacement-based seismic designs are presented, which could be according to different criteria including standard of soil yield behind abutment, standard of soil yield of foundation, standard of noncollision between abutment and beam, and standard of engineering experience. Preliminary results show that the displacement obtained from criteria standard of soil yield of foundation is more reasonable because it is able to reflect the dynamic response law more truly.