Slope Stability Analysis And Dynamic Response Earthquake Research

The earthquake triggered slope failure has brought huge damage, not only the bigeconomic losses and death, but also environment problem. It has been one of theimportant and topic for many decades in geotechnical and earthquake engineering howto reliably assess the slope stability and predict its instability under earthquake. Thereare many factors to influence the slope stability; it makes it very difficult to explore themechanism of slope failure or instability. However, some researches had made greatprogresses in modeling the dynamic response of some kinds of slopes failure based onthe advanced numerical analysis and shaking table test and in-situ experiments. Thegeneral idea of the nowadays popular dynamic analysis for slope stability ispseudo-static or static analysis instead of the dynamic response modeling. But, in recentdecade, the advanced numerical analysis methods and geotechnical experiments make itpossible to do dynamic time-history analysis. In this thesis, one new method forsimulating the dynamic response of clay slope under seismic load was done based onFEA and shaking table test. In this model, some important factors to affect the slopestability were analyzed, and the characteristics of seismic parameters including the inputdirection, strong earthquake amplitude etc had been discussed how to impact the slopestability. This new method and model had also been tested in stability assessment of anactual slope, and some valuable conclusions had been got.1)Illustrating a typical clay slope in southwest region of China, the traditional limitequilibrium method and strength reduction factor methods of finite element and finitedifference were used to assess its instability before and after the earthquake invadingrespectively. It has been proven that the strength reduction method based on FEA ismore rational to analysis the slope stability than the other methods. The parametersensitivity related to slope stability in finite element strength reduction method isstudied. The Correlation among these parameters and slope safety in differentgeological condition were systematically discussed, some reliable results could be usedto reduce the slope failure risk and instability prevention. 2)To study the effect seismic wave input direction and earthquake magnitude onslope dynamic response analysis the earthquake invading direction in the horizontal,vertical and two-way coupling and different seismic acceleration, velocity were selectedto model the dynamic response of the above clay slope, the results show that the seismicinput has a particular effect in certain kinds of slope, but in most of cases, the horizontalseismic input is the most unfavorable direction for slope safety. Both seismicacceleration and velocity have huge effect on slope stability.3)In order to estimate the effect of slope angle on its stability, the safety factors inthree slope gradient with1:2,1:1,1:0.5for a homogeneous clay were calculated underhorizontal seismic waves input. Comparing the numerical analysis with the shakingtable test of slope failure, it has been found that the seismic acceleration, displacement,and velocity have obviously different effect on slope failure, which is useful fordifferent types of slope treatment.4)The dynamic response of one clay slope with no steps, one step and two-step inslope surface were analyzed, the distribution characteristics of response velocity,acceleration, displacement in slope were explored, and the weakest surface in differentslope topologies were found, which could be given a reliable suggestion for slopereinforcement.