Reliability Analysis Of The Slope Based On The Finite Element Limit Equilibrium Method

As one of the fundamental problems in soil mechanics,slope stability has been paid attention in geotechnical engineering.Certain safety factor method and uncertain reliability evaluation method play important roles in slope stability analysis.Experienced with complicatedly temporal and spatial procedures,geotechnical structure is investigated in slope stability and its formation history,existing environment,composition structure and physical and mechanical characteristics are uncertain.Existing methods of reliability analysis cannot accurately evaluate the slope reliability,because typically they only consider the single uncertainty factor,ignoring the characteristic of spatial variability featuring the randomness of soil parameters.However,the random field theory model is able to consider the spatial variability.In order to evaluate the reliability of slope stability,a random field model is built to capture the spatial variability of soil,based on the finite element limit equilibrium method.The main work of the thesis is as follows:1.This paper introduces several kinds of uncertain factors and classifies them,compares the common methods of reliability calculation,and through the introduction of local averaging method,combs the related concepts of stochastic field theory,and expounds the theoretical Foundation,the definition of safety factor and the calculation method of the finite element limit equilibrium method around the limit equilibrium condition.The reliability analysis framework of stochastic field slope based on finite element limit equilibrium method is established,and the relevant examples are analyzed.2.Considering the spatial variability of soil parameters and the influence of different autocorrelation coefficients on slope reliability,the following conclusions are obtained:(1)The results of soil reliability analysis are related to the autocorrelation distance of soil,the failure probability of slope is positively correlated with the autocorrelation distance of soil,and the reliability index is more sensitive to vertical fluctuation distance.(2)through the relevant examples,it is shown that reasonable estimation of equivalent correlation distance has a very important influence on the calculation of the final reliability analysis.(3)The existence of the critical coefficient of variation is verified,so that when the variation coefficient is less than the critical coefficient of variation,ignoring the spatial variability of the soil will lead to an overestimation of the slope failure probability.Conversely,when the variation coefficient is greater than the critical coefficient of variation,ignoring the existence of spatial variability will underestimateBy constructing the method of slope reliability analysis based on finite element limit equilibrium method,this paper studies several factors affecting the reliability analysis and calculation of soil slope under the condition of spatial variation,which can provide theoretical reference and calculation ideas for future slope engineering reliability analysis and calculation.