Upper-bound Stability Analysis Of Three-dimensional Slopes Subjected To Seepage Forces Based On Discretization Method

Slopes are common structures in geotechnical engineering and a large amount of groundwater is often stored inside slopes.The groundwater in the slope often flows under the conditions of some external factors like rainfall and external water level fluctuation.The flow of underground water results in seepage force in the slope,reducing the stability of the slope and even causing slope failure.Therefore,it is of great engineering significance to study the stability of slope under seepage forces.Based on limit analysis theory,this thesis presents a method to study the stability of three-dimensional slope under seepage forces.The main work and results of this thesis are as follows:1.The stability of three-dimensional rock slope subjected to seepage forces is studied.This thesis introduces the three-dimensional rotational failure mechanism and its discretization method.A method to calculate the seepage force by combining numerical simulation with discrete method is presented herein.Safety factors of three-dimensional slopes are obtained by optimizing the work rate balance equation.The effects of slope geometric parameters and strength parameters on slope safety are analyzed based on these charts.2.The stability analysis of three-dimensional slope under the condition of water level fluctuation is carried out,and four different types of water level fluctuation conditions are considered.Obtained safety factors are drawn in a series of stability charts and the influence of water level fluctuation on slope stability is analyzed.At the same time,the influence of geometric and strength parameters of three-dimensional slope on slope stability is discussed.3.The numerical simulation method is used to analyze the stability of three-dimensional slope subjected to seepage forces and the numerical simulation results are used to verify the correctness of the method proposed in this thesis.The seepage calculation module of FLAC 3D is used to calculate the seepage inside the three-dimensional slope.The characteristics of the pore pressure field are analyzed and the method of deriving the pore water pressure field by FISH program language is introduced.4.Using the three-dimensional slope stability analysis method proposed in this thesis,the stability of two slopes in practical engineering is evaluated.By comparing safety factors obtained from this method and those from the limit equilibrium method,the applicability of this method in the analysis of practical problems is verified.This thesis contains 50 figures,10 tables and 121 references.