Dynamic response and failure characteristics of a slope with bedrock subjected to earthquakes and rainfall in shaking table tests

In this study, shaking table tests were conducted to investigate the seismic response and failure characteristics of a slope with bedrock subjected to earthquakes and rainfall. Group 1 was subjected to earthquakes, while Group 2 was subjected 40 mm rainfall, followed by earthquakes. The acceleration, earth pressure, pore pressure, soil strain and displacement of the slope were recorded and analysed, and the failure mechanism of the slope was discussed based on the failure process of the slope and marginal spectra. The results indicate that the dynamic response of the slope intensifies under post-rainfall earthquakes and the acceleration amplification factor, earth pressure, soil strain, and displacement of the slope exceed those observed during earthquakes alone. The slope exhibits less stability because the soil weakened after rainfall and the pore water pressures were generated during the post-rainfall earthquakes. As a result, the seismic damage to the slope was more severe under earthquakes after rainfall than that during only earthquakes. The progression of cracks and the potential sliding surfaces of the slope remained consistent during the earthquakes before and after rainfall. The failure process of the slope under earthquakes after rainfall occurs in three stages: tension cracks at the slope crest, shear collapse at the slope foot, and landslides. The slope exhibits a tension-shear failure mode, and the anti-sliding forces on the slope near the foot are essential for maintaining the seismic stability of the slope. The soil-bedrock structures affect the failure characteristics of the slope.