Analysis Of Slope Reliability Based On Stochastic Response Surface Method And Stochastic Field Model

The study of slope stability is very important for the prevention and treatment of landslide disaster,in order to solve the slope stability problem more accurately,it is necessary to consider the uncertainty caused by environment,statistics,model and other factors in the process of slope stability analysis.At present,most of the research on slope reliability only considers the uncertainty of stochastic parameter distribution,but mostly ignores the uncertainty factor of spatial anisotropy of soil parameters,so there is a certain error in the results obtained.In this paper,the safety factor of slope stability is analyzed by strength reduction and subtraction,the stochastic response surface method of slope reliability based on Hermite polynomial expansion is established,and the influence degree of shear strength parameter correlation of different rock and soil layers on the mean and standard deviation of slope safety coefficient and the probability of stable failure is studied.The calculation model of slope with airport is further put forward,and the influence of spatial anisotropy of soil parameters on slope reliability is analyzed.The main research contents are as follows:(1)In order to calculate and analyze the safety factor of slope stability,the calculation principle of strength reduction and subtraction of slope stability analysis is expounded,and the finite difference calculation model of slope stability Analysis FLAC3 D is established,and compared with the limit equilibrium method.The results of slope stability Analysis show that the calculation results of strength reduction and limit equilibrium method are close,which shows the reliability of slope stability Analysis FLAC3 D finite difference calculation model.(2)Combined with the Latin Super cube sampling and Nataf transform,a stochastic response surface method analysis model of slope reliability based on Hermite polynomial expansion is established,and the slope reliability problem of three layers of rock and soil slope is analyzed,which can not only meet the calculation accuracy,but also improve the calculation efficiency effectively.Based on this model,the influence degree of shear strength parameters of different rock and soil layers on slope safety coefficient and standard deviation and stability failure probability is studied.The results show that the correlation between shear strength parameters of different rock and soil layers has a small influence on the mean value of slope safety coefficient,and the influence degree of slope safety coefficient standard difference and failure probability is quite different,and with the enhancement of correlation,the overall downward trend is decreasing.(3)In order to study the influence of spatial anisotropy of soil parameters on slope reliability,the C + + language is used to discretize two-dimensional with the airport by local average method,and the covariance matrix is obtained,and the calculation model of slope with airport is established by the mean and standard deviation of input parameters.Combined with strength reduction and stochastic response surface method and Monte-Carlo method,the influence law of correlation distance,soil adhesion force and internal friction angle variation coefficient on slope reliability under stochastic field model is compared and analyzed.The results show that with the increase of the correlation distance of the model,the failure probability of the slope increases with the increasing variation of the relative coefficient of the same soil and the variation coefficient of the internal friction angle.At the same time as the relevant distance of the airport calculation model,The failure probability of slope shows an upward trend with the increase of the coefficient of variation of soil adhesion force or the coefficient of variation of internal friction angle,and the influence of the correlation distance change of vertical direction in the airport calculation model is more obvious than that in the horizontal direction.