Stability Analysis Of Gravel Slope Subjected To Rain Infiltration

Landslides are serious natural phenomenon. The gravel landslide is one of themain types which occurred. It is generally compose of slope deposits, eluvial, alluvialand collapse. The gravel landslide is closely related to rainfall. The deformation andfailure of gravel landslide is a dynamic process. It is necessary to analyze the complexstructure, composition of rock and soil.Based on the saturated-unsaturated seepage theory, the auther analyzes theinfluence of rainfall on the unstaturated gravelly slope and its’stability. The changeofseepage in the slope under different rainfall conditions is analyzed. On the basis ofcalculated transient seepage field and the shear strength theory of unsaturated soil, thetransient stability of gravel soil slope is analyzed.Conclusions can be drawn as follows:1. Based on the unsaturated gravel soil’s characteristics and saturated-unsaturatedseepage theory, the factors of rainfall infiltration are analysised. Physical simulationof rainfall-induced landslidesand two-dimensional finite element methodare employedto analyze theslope stability due to rainfall.Soil-water characteristic curve (SWCC) is the key to analyze the strength anddeformation characteristics of unsaturated soil. Using the pressure plate,the SWCCtests for three different soils considering dehydration process are done. The resultshows that the grading of the soil has a significant affection on the SWCC. The coarseand poorer grading soil has the steeper SWCC.A physical simulation of rainfall-induced landslides is carried out. According tothe volumetric water content sensors which are buried in the siope, the change of themoisture content in different depths under the different rainfall intensityis is observed.Based on the experimental results, the variation of the moisture content in differentrainfall intensity and different depths are investigated.A seepage model of slope stability is established using the software VADOSE/W,and the implementation steps of the finite element analysis of rainfall infiltration isgiven. Through one case study, the effect of the changes of rainfall intensity, rainfallduration, antecedent rainfall, and soil parameters onthe seepage field are discussed.The soil’ anisotropy is taken into account. 2. The seepage and stress fields influence each other. Seepage field changes themechanical properties of the soil, and the soil stress directly affects the permeability.From the theory of fluid-solid coupling, the basic equations for seepage-stresscoupling are dirived. The finite element model of fluid-solid coupling is established.3. The mechanism of slope stability and analysis method under rainfallinfiltration are described. The transient pore-water presser distribution is calculated byusing the finite element software ABAQUS to analysis the slope’s stability. Thechanges in the safety factor under the conditions also can be found out.