Study On The Effects Of Rainfall Infiltration On Rheological Stability Of Red Clay Slope

There are a lot of slopes in field of civil engineering and the analysis of slopestability has been the focus of research to engineer, there were two main methods foranalysis slope stability: one was the traditional method of quantitative analysis, suchas engineering analogy method, the limit equilibrium method, etc, the other one wasnumerical methods, such as finite difference method, the finite element method, etc.For simple concept and can directly give the safety factor of slope, the limitequilibrium method was widely used in engineering practice, but for the limitequilibrium method there were many deficiency: the soil was regarded as a rigidplastic body, not easy to consider the external influence of factors such as rainfall, thesliding surface shape and position assumed before calculate, etc. Comparison of finiteelement method and limit equilibrium method, the finite element method was moreflexible, constitutive model of soil in finite element method including elastic model,elastic-plastic model and rheological model and any point’s stress or strain can obtainthrough the last result.The practical project indicates that the clay soil has the very strong rheologicalproperties, the deformation of soil show the unique characteristics especially underlong-term rainfall infiltration conditions, hunan province occurs many landslidedisaster in plum rains season related to rheological properties of soil, therefore tostudy the stability of rheological clay soil slopes under rainfall conditions is necessaryand meaningful. This paper embark from the elements theory and through the indoorsoil test, the rheological constitutive model was established, CAE software ABAQUSwas used to analysis the stability of the red clay slopes. The main research contentsand conclusions are as following:1. Previous landslide hazard of red clay slope which occurred at XiangtanUniversity gymnasium found that: red clay shows significant rheological propertiesunder rainfall conditions, analysis the physical and mechanical properties of the redclay through the indoor soil test, and then elements theory was used to establish theelasticity-viscoplastic model which accurately reflect the rheological properties of redclay.2. Collection the hydro-meteorological, geological structure, topography ofstadium regional and combined with the soil rheological constitutive model,ABAQUS software was used to established the red clay soil slope stability model in which consider the rheological properties of the soil under rainfall infiltration.3. Design the orthogonal pilot program of the factors that influencing thestability of slope, like viscosity coefficient, rainfall intensity and permeabilitycoefficient etc, ABAQUS software was used to analysis the impact of variousparameters on the stability of soil slope. The law of four factors affect on the stabilityof slope as follow: poisson ratio> permeability coefficient> viscosity coefficient>rainfall intensity.4. According to the results of orthogonal test, the key points displacement asobjective function, the maximum displacement and the smallest displacement of thekey points of the slope under impact factors was got through the ABAQUS softwaresimulation. Comparison two programs displacement-time curve of key points and gotthe displacement characteristics of key points. The analysis results show that: underthe design conditions in this text, the key point show the attenuation creepcharacteristics and the slope tend to last in the steady state.5. Finally the trapezoidal slope model was established, the key pointsdisplacement was compared under the same impact factors between trapezoidal slopeand undisturbed slope.The analysis results showed that: trapezoidal slope enhancedthe stability of the red clay slope.