Study On Infinite Slope Stability Based On Random Field Method

With the further deepening of China's infrastructure construction and China's vast territory,slope stability problem is inevitably involved in civil engineering,transportation,water conservancy and other engineering construction.Therefore,how to scientifically and efficiently assess slope safety has always been a hot issue in the field of geotechnical engineering.The deterministic analysis method of slope stability combined with reliability analysis method can comprehensively and reasonably evaluate the slope safety.Based on the random field theory,a reliability analysis method for infinite slope stability considering the spatial variability of parameters is established.At the same time,the deterministic analysis method is used to verify and study the infinite slope stability.The main work and achievements are as follows:(1)This paper introduces the common slope stability analysis methods briefly.Based on the random field theory,a 1D non-stationary random field model which is suitable for the soil parameters of infinite slope is proposed.Based on this model,a reliability analysis method for infinite slope considering the spatial variability and non-stationary of soil parameters is established.At the same time,based on the random field theory,the seismic stability analysis method of infinite slope is established.(2)Taking the infinite undrained slope as an example,the effect of the spatial variability and non-stationary of undrained strength on the reliability of the infinite slope is explored:It is found that the probability of infinite slope failure decreases with increasing gradient of mean undrained shear strength;Not all failure surfaces occur at the base of the soil layer,as greater values of the gradient of mean shear strength lead to higher values of undrained shear strength on the average across the entire soil layer,the frequency of the critical depth occurring at the base decreases.Based on the deterministic analysis method,the effect of seismic force on the critical slope angle is analyzed:The critical slope angle decreases from 450 as the horizontal seismic coefficient is increased when the infinite slope is subjected to horizontal seismic loading;For the infinite slope subjected to horizontal and vertical seismic loading,the effect of vertical seismic loading on the critical slope angle is gradually significant as the horizontal seismic coefficient is increased.(3)Taking the infinite frictional/cohesive slope as an example,horizontal seismic loading and combined horizontal and vertical seismic loading are both considered.Based on the deterministic analysis method,the effect of seismic force on the critical slope angle is analyzed:It is found that different from the undrained slope,the critical slope angle of the infinite frictional/cohesive slope is not only affected by horizontal and vertical seismic loading,but also affected by the height of the slope,the weight of soil,the effective cohesion and effective internal friction angle of soil.Based on the random field theory,the effect of the seismic force on the reliability of the infinite frictional/cohesive slope is explored:It is found that the probability of infinite frictional/cohesive slope failure increases significantly as the horizontal seismic coefficient is increased;When the horizontal seismic coefficient is small,the effect of vertical seismic loading on the reliability of the infinite frictional/cohesive slope is not significant.