MECHANISM AND STABILITY ANALYSES OF PROGRESSIVE FAILURE OF LANDSLIDE

Based on the research of landslide stability analyses, the new failure stability analyses of thrust-type landslide are established. Based on the mechanism of thrust-type landslide, critical stresses slice block(SB)(or element) and relative determinations are suggested. Two failure modes are proposed for the progressive movement landslide, the modeⅠ:the whole slope failure is occurred along the soft-weak layer, the modeⅡ:The landslide failure is occurred in the trailing's edges along the soft-weak layer, but its ahead shear failure is happened along the sliding body. The critical stress state moves from the behind zone to the front zone of landslide progressively. TheScurve property of time and deformation relationship is shown for the different points on the sliding surface during deformation period, and a parabolic curve is presented for the relationship of deformation of different points on the sliding suface and height of landslide by means of results of landslide mechanism. The two kinds of curve properties between time and deformation are proposed based on the mechanical behavior classification of rock-soil mass: unstable and stable time and deformation curve. The characteristics of current stability analyses is researched, the stability analysis method of comprehensive sliding force and anti-sliding force, main thrust force method and displacement method based on deformation are suggested. The movement of landslide is studied, the definition of main sliding direction of landslide is proposed. The cause of no convergence is analyzed for FEM, a new method to take the sliding face as a boundary condition of FEM is proposed for landslide stability analyses, the boundary condition of sliding surface can described not only as perfect elasto-plastic model(PEPM), but also the new constitutive theories(JCM).The results of stability analyses by PEPM can take the comparisons with the traditional slice method, the real stress and strain fields can obtained by other models for landslide. The determination of potential sliding surface is determinate by probability method, energy principle and in-situ exploration method.