Mechanical Model of Shear Deformation of Steep Sandy Slope due to Rainfall

Abstract

Abstract In order to simulate shear deformation and failure of steep slope sandy slope due to rainfall, shear deformation model of infinite slope is newly developed. The model consists of 1-dimensional seepage analysis and 2-dimensional deformation analysis. The latter is newly developed based on the stress-strain relation on Mobilized plane proposed by Matsuoka and transformation of stress and strain on the Mobilized Plane into 2-dimensional stress and strain. In the model, stresses are corrected with bond stress due to suction so that the model can express the change of stress ratio in correspond to the decrease of suction and proceeding of shear deformation due to the seepage of rainfall. The analysis by the proposed model is compared with the results of the slope failure experiment. As results, the analysis shows good agreement with the experimental facts which are, (1) visible shear deformation occurs after volumetric water content largely increases, (2) shear strain becomes larger with the increase of degree of saturation, (3) shear strain at deeper soil layer proceeds at higher degree of saturation than that at shallow soil layer, (4) shear strain proceeds at smaller degree of saturation when a inclination is larger. It shows the proposed model can simulate the actual shear deformation of the slope.