Dynamic response and dynamic failure mode of the slope subjected to earthquake and rainfall

Abstract

Rainfall and earthquakes are two of the major factors that provoke landslides. To investigate the seismic response and dynamic failure mode of the slope with tilted highly weathered layer subjected to earthquake and rainfall, two slope models with different moisture content were constructed and tested by using a large 1-g shaking table. It was observed that the acceleration amplification coefficient (AAC) in bedrock increases with increasing earthquake amplitude when the El Centro and Wenchuan acceleration amplitude are not larger than 0.33 g in two models, and the AAC in highly weathered layer decreases with increasing elevation and with increasing earthquake amplitude. The water content of the highly weathered layer can affect the dynamic response of the model. The acceleration response of model with general moisture content is weaker than that with saturated moisture content, which is the same as the displacement of slope surface. The marginal spectrum identification of dynamic damage process shows that the seismic damage occurs in the intercalated layer of the middle part slope firstly, and then it occurs in the intercalated layer of the lower part slope and in the covering layer, and finally, it occurs in the intercalated layer of upper part slope. Based on the marginal spectrum identification of dynamic damage process, the strain response, the displacement response, and the phenomenon of dynamic damage, the failure mode of the slope with tilted highly weathered layer can be concluded as the cracking–shearing–slippage and cracking–shearing–crushing.