The Response Analysis Of Fill Slope Under Seismic Excitation

With the launching of the national economy, more and more projects have been related to the stability of fill slope. According to statistics, most failure of slopes is induced by the earthquake and rainfall, due to seismic excitation, a large number of slopes fail. Slope stability under earthquake is very complicated, it is affected by the earthquake, slope topography, rainfall, groundwater and the physical properties of the slope, and many other factors. Studies of slope stability under earthquake involve many disciplines, not only seismology, engineering geology are closely related, but also mathematics, computational mechanics and other disciplines are also closely linked. The study of slope stability under seismic excitation is always a major and difficult problem in the Geo-Engineering,, with great practical and economic significance. On the basis of previous research, using a high fill slope in the Nuclear Power Plant of Dafan Hubei as example, following work has been done:(1) Using limit equilibrium method, which is commonly used in the analysis of slope stability, we can't get the slope displacement due to seismic excitation. While the non-linear method in dynamic analysis is time-consuming and can't be easily applied by general engineers, this article attempts to involve quasi-static assumptions to the numerical simulation analysis, pointing out in this method, the side boundary should parallel with the composition of force s applied to the model, and the bottom boundary should set perpendicular to force;(2) Comparing results from the numerical simulation analysis with quasi-static assumption to those from limit equilibrium method, the safety factors are similar, and the numerical simulation analysis with quasi-static assumption can make up the limitation that with the ordinary limit equilibrium method we can't calculate the slope displacement, which is induced by the earthquake;(3) Introduced the the response spectrum method which is commonly used in structural analysis to the stability analysis of the slope under seismic excitation. Then point out that the side boundaries in the slope model with response spectrum method should be viscous boundary, rather than the commonly used fixed or free boundaries. By comparing results from the response spectrum method to results from the numerical pseudo-static analysis method, this article prove that the use of viscous boundary in the stability analysis of the slope with the response spectrum method is appropriate;(4) Using the commonly used non-linear method to analyse the stability of the fill slope under seismic excitation, I get the relationships of acceleration and displacement to the height of the history point. Comparing the displacement results to those form the response spectrum method and the numerical pseudo-static analysis method, it proves that the latter two methods have not involve the energy dissipation which is practical;(5) For the first time, the stability analysis with non-linear method involves the travelling wave effect in this article. And results prove that it is necessary to involve the traveling wave effect in the stability analysis with non-linear method.