Physical model study on the bank slope of thick sandy soil under rainfall

Due to its special physical and mechanical characteristics, the destabilization failure process of sandy soil bank slope is significantly different from that of general clay soil bank slope. In this experiment, the deformation and failure process of thick sandy soil type river bank slope under different rainfall intensities and bank slope ratios was studied. A total of five sets of indoor physical model tests were designed, and each set of tests was conducted with buried moisture meter, micro pore pressure meter and lead thermometer for measurement, and the whole process of bank deformation and damage was recorded by high precision camera. The test results show that the cohesive force of unsaturated sandy soil tends to increase and then decrease with increasing water content, and has an obvious peak value, and the angle of internal friction tends to decrease. The deformation and damage of sandy soil bank slope under different rainfall intensities and slope ratios show two different mechanisms. The short-duration rainfall will form a saturation zone on the surface layer of the slope, which prevents the infiltration of rainwater, and the water transport varies at different depths of the sandy soil layer, so the infiltration path of rainwater is not a single vertical infiltration. The bank erosion failure occurs under the coupling effect of rainfall scouring, rainfall infiltration and gravity erosion. This study can truly reflect the scour characteristics and collapse failure process of sandy slopes under complex conditions, and provide a reliable reference for establishing the theory and method of slope stability analysis under the joint action of multiple factors.