Strength Subtraction In The Slope Stability Analysis Research

Slope stability analysis is the basis and premise of slope designing, through the stabilityanalysis of the slope, we can clearly know whether the slope is instability or in the process ofslope excavation, the earth pressure generated by slope soil will affect the overall stability ofthe slope, which not only concerns the choice of the slope shoring scheme, but also in turnprovides scientific mathematical basis for supporting structure designing.Nowadays, the slope stability analysis is still not been completely explained, because aseries of restricting factors such as geological condition of the slope, parameters of the rockbody, obliquity of the slope and so on are more complicated. For homogeneous slope, thetraditional methods mainly includes: limit equilibrium method and limit analysis method, etc.At present, in China the main method to analyze the slope stability is the limit equilibrium,but the premise is that the position and shape of sliding surfaces need to be known in advance.As to a homogeneous soil slope, the dangerous sliding surface can be found by a variety ofoptimization method. With regard to the rock slope, the situation is relatively complicated dueto different structure, occurrence and discontinuous surface structure existing in the actualrock mass, the dangerous sliding surface and corresponding safety factor are not still searchedout by the method of the traditional limit equilibrium.In recent years, to the analysis of slope stability, people gradually combine the traditionalplane statically determinate mechanics problems with unceasing enhancement computertechnology perfectly, which show the internal soil unit force of the rock body to its fullpotential. Among which, one of the most prominent is to use the finite element method toremove a variety of bondage encountered by former scholars’ analysis on the slope stability,so it reflects the stability of the slope as well as possible. But the finite element analysismethod also experiences a rapid evolution process. With the numerical simulation modelcloses to the real condition of the soil constantly, the conclusion made by this method hasmuch research valuable and applicability.This thesis, by using finite element strength subtraction mainly, it has carried on thesystematic analysis on the homogeneous slope, and confirms the feasibility of its applying inthe project and some characteristics of this method that is superior to traditional limitequilibrium method. The research results not only get the dangerous sliding surface of jointedrock slopes and corresponding safety factor, but also can make a stability analysis on thebreakthrough and the penetration of jointed rock slopes, meanwhile considering the groundwater and construction process’ influence on slope stability. Besides, in the applicationand practice, it offers the diversity of the supporting structure and the combined effect of bothretaining structure and geotechnical material, which provides new insight into the slopestability analysis.Taking a homogeneous slope as an example, this thesis firstly adopts the traditional limitequilibrium method to analyze the stability of the slope, and then use FLAC strengthsubtraction in finite difference method to analyze it, and finally compares the calculationresults got from the above two methods, it is found that if using suitable soil constitutivemodel, calculation from strength subtraction closes to the result from the limit equilibriummethod, which a little higher than the limit equilibrium method, that is, about2%~3.5%onaverage, what’s more, the potential slip surface location got from the two calculation methodsis very close. Besides, the paper also introduces the development course of the finiteelement strength subtraction in recent years, from the beginning to the assumptions analysistheory of slope to gradually remove assumptions towards the evolution of the characteristicsof a more real simulation internal structure of soil, it works out the applicability andsuperiority of FLAC based on strength subtraction in the study of slope stability.