Dynamic Response And Stability Analysis Of Slope Under Strong Earthquake

The research of slope stability under strong earthquake is always the hot issue inthe field of geotechnical engineering. Therefore it has very important practicalsignificance to do more in-depth research. The median safety coefficient calculatedfrom the traditional limit equilibrium method used by some scholars can not reflectvarious uncertainties during slope engineering. The other scholars put forward thatevaluate the stability of the slope under dynamic conditions by the minimum safetyfactor and the average minimum safety factor. The minimum safety factor is the safest.The instantaneous instability of the slope didn’t necessarily make the slope destroycompletely. The minimum average safety factor is lack of clear physical meaning andproject risk decision meaning. In view of this situation, the author proposed a newevaluation method of dynamic slope stability, and validated that the obtained results metaccuracy requirements in all aspects. First, this paper analyzed and compared highearth-rock dam models under three different operating conditions. Dynamic safetyfactor then was obtained. Apply the iterative calculation to the obtained dynamic safetycoefficient, which was combined with the JC method in reliability calculation method.The final dynamic reliability safety factor and reliability index could be obtained.Finally, comprehensive evaluation can be applied. JC method is a method which isapplicable to solve engineering structure reliability index under arbitrary distributionand is easy to understand. The precision can satisfy the need of engineering practice.The slope stability analysis method combined with reliability theory underrandom-probability analysis can fully consider various uncertainties, which makes itmore importantly practically significant. The main research contents and achievementsof this paper are as follows.①.The author analyzed the current situation and the developing trend of theearthquake slope and the reliability of slope stability under earthquake. Seismic load isloaded on the model according to the dynamical analysis of the slope under strongearthquake. Use ANSYS General post processor that is the POST1General processor for programming. The distribution cloud map of dynamical safety coefficient wasgained. Then dynamical safety coefficient was gained on the base of the distributingcloud map.②.Establish three different kinds of earth-rock dam model. Then Input twodifferent seismic intensity kinds of seismic waves. Model conditions of six kinds ofearth-rock dam would be obtained. Analyze the dynamic response under the action ofstrong vibration. The stress diagram、shift diagram and the time history curve of thedisplacement、velocity and acceleration of the crest、the bottom and the toe of the slopewould be obtained. Contrast the variations under different slope ratio and differentseismic intensity.③.On the basis of comparison of dynamic response, analyze the reliability changerule of the slope under the action of the earthquake. At the same time, rock materialparameters and the randomness of the seismic load should be taken into account. Safetyfactor of the slope and reliability index were obtained by the normal distribution. Fit thelaw relationship figure between the safety coefficient、reliability index and the height ofthe dam.④.Make the JC iterative computations to the results in every model conditioncombined with the JC method in the reliability theory analysis method. The JC iterativecalculations just need the simple Excel program. Finally, the dynamic reliability safetycoefficient and the reliability index were calculated. The results revealed that safetycoefficient of six different operating conditions under strong earthquake were largerthan1. The tendency was steady. The bigger the slope ratio was, the bigger the dynamicreliability safety coefficient was. However, the larger the earthquake intensity was, thesmaller the dynamic reliability safety coefficient was and the more unstable theearth-rock dam was. Through verification, this evaluation method could meet theengineering accuracy.