Method For Determining Multiple Failure Modes Of Complex Slope And Its Engineering Application

As a main source of geological disaster,landslides bring more losses to our country and people.It is therefore,of great importance to evaluate and reinforce the slope stability level.The failure modes exhibit diversity in slope failure process especially for multiple stage,multiple layer based slopes.Different failure modes lead to different failure consequences and failure probabilities.The research on the determination of multiple failure modes will provide much insight into geotechnical engineering and provides an efficient tool for geotechnical practitioners to evaluate the level of slope stability,and to make decisions on rehabilitating slopes.The main findings are as follows:(1)Comprehensive comparison between limit equilibrium method and strength reduction method was made and it was noted that both methods can yield an effective factor of safety and failure mode for deterministic slope stability problem.They can be appropriately extended for slope reliability analysis;(2)The inherent variation in soil properties was considered by simulation in random variables.Monte Carlo simulation(MCs)was performed in order to locate the distribution of surrogate slip surfaces based on the fact that for each of sample in MCs,the slip surface with the minimum factor of safety can be regarded as a surrogate slip surface;(3)Case studies for simple,multiple stage,and multiple layer based slopes were conducted and the results show that the deterministic critical slip surface can not control the performance of slope system in terms of failure probability especially for complicated slopes such as multiple stage based or multiple layer based slopes.Besides the deterministic critical slip surface,those surrogate slip surfaces with relatively larger volume of sliding masses deserve more attention;(4)Tailings dam in Zhaoyuan and a brown coal open mines slope were studied using the proposed methodology to locate the surrogate slip surfaces and to compare the failure probability and also the volume of sliding masses with the aim to provide much insight into decision making.