Analysis Of Slope Stability Under The Condition Of Slone Surface Flow And Fracture Priority Flow Coupling

The existence and characteristics of fissures are the internal causes of a series of problems in fissured soil slope engineering,preferential flow refers to the phenomenon of rapid movement of water bypassing the soil matrix through preferential paths in the medium with fissures,It is an external factor that causes the instability of fissured soil slopes.Therefore,it is of academic significance and practical value to study the preferential flow of fissured soil slopes and the slope stability caused by the preferential flow.Preferential flow refers to the phenomenon that water bypasses the soil matrix through a preferential path in a medium with cracks,and it is an external factor that causes the instability of cracked soil slopes.Therefore,it is of academic significance and practical value to study the preferential flow of fissured soil slopes and the slope stability caused by the preferential flow.This thesis draws on the research results of preferential soil flow from many scholars at home and abroad,introduces the concepts of preferential flow and slope runoff into the seepage and stability analysis of fractured soil slopes,and establishes a two-dimensional fractured soil slope surface by numerical analysis.The runoff-preferential flow coupling model,numerical simulation reveals the effect of the preferential flow of fissured soil on the saturated-unsaturated seepage movement law and stability of the fissured soil slope.The main research works and results of this thesis are as follows:(1)Firstly,this thesis introduces the classic theory of slope runoff and the current status of slope runoff research.Motion wave equation and momentum equation are introduced to describe the slope runoff process.Then,the Preissmann implicit format is used to discretize the slope runoff equation and MATLAB is used to compile the slope runoff calculation program.The correctness of the slope runoff program is verified by comparing with the previous analytical solutions of slope runoff theory,and the case analysis to study the whole process of slope runoff from rising to backwater during rainfall.(2)Based on the theoretical analysis and previous research results,the fractured soil is divided into matrix and fissure domains based on the two-domain model,and the Richard mathematical model is used to simulate the water movement in the matrix domain.As a part of the boundary of the matrix domain,considering the infiltration of rainwater comprehensively,the single-fracture preferential flow coupling model was established by the slope replenishment effect on the fracture.(3)Based on the basic theory of saturated-unsaturated soil water movement during rainfall infiltration.And the theory of ADI alternating implicit difference method is introduced to discretize Richard's two-dimensional infiltration equation with water content as the control variable.By programming MATLAB to use the prediction-correction method to solve the discrete equation calculation program,the slope runoff equation and the saturated-unsaturated infiltration equation can be coupled by the infiltration rate as the source term.In this thesis,the coupling model is verified by comparing the two examples with the slope runoff-infiltration coupling model that does not consider the priority flow and the FRCATURE model with the slope runoff-infiltration coupling considering the priority flow.Correctness.(4)On the basis of the priority flow coupling model,compile a program to calculate the safety factor of infinite slope.Perform infinite slope stability analysis.The analysis results show that:the slope safety factor under the effect of water movement of preferential flow,the change of safety factor with rainfall duration is much lower than that without considering the priority flow;the gap spacing has a greater impact on the stability of infinite slope,and the crack The denser the spacing,the smaller the safety factor at the most dangerous sliding surface,and the closer to the interface between the fissured soil and the ordinary soil layer,the easier the slope is to damage along the interface;the greater the depth of the crack,the easier the slope to occur Shallow failure;the safety factor of the fissured soil slope will be greatly reduced when considering the strength reduction;the fissured soil slope is prone to damage along the interface of the fissured soil along the shallow layer.When studying the stability of fissured soil slopes,the strength reduction of fissured soil layers and the effect of preferential flow in fissures on soil infiltration should be considered.