Physical model test on deformation and failure mechanism of deposit landslide under gradient rainfall

Rainfalls with heavy intensity and long duration are the main factors that trigger landslide. A large-scale test of physical model of landslide induced by gradient rainfall is conducted to investigate the mechanism of landslide caused by rainfalls with an indoor large-scale physical model test system. By monitoring the variation of pore water pressure, soil pressure, slope surface displacement, and groundwater level, the deformation and failure mechanism of deposit landslide under gradient rainfall are studied. The results show that the pore water pressure and soil pressure increase with the increase of the duration of rainfall, and the greater the rainfall intensity is, the greater the peak values of pore water pressure and soil pressure are. The intensity and duration of rainfall are the main influencing factors of landslide deformation. The decrease of effective stress and the rise of groundwater level are the root causes of landslide deformation. During a rainfall, excessive pore water pressure appears in the slope, which can be used as an early warning indicator of landslide deformation and failure. The deformation of slope body is nonlinear and shows a stepped pattern under gradient rainfall. During a rainfall, the toe of the slope is usually damaged first. Tension cracks appear in the rear edge and the middle part of the slope successively, showing the characteristics of traction failure.