Stability evaluation of slope subjected to seismic effect combined with consequent rainfall

Abstract A large number of field investigations of earthquake damage have shown that sometimes slopes instability occurs as a result of a series of post-seismic ripple effects rather than of merely seismic load or ground motion, among which a combination of earthquakes and post-seismic rainfall is a typical contribution for slope instability. In this paper, taking a slope in Southwest China as an example, failure mechanism and stability of slope under seismic load and heavy rainfall are analyzed with consideration of dynamic load and unsaturated infiltration using GeoStudio software. Results indicate that, the acceleration of earthquake is sharply amplified at the top of the slope, resulting in instantaneous tension stress, which causes tension cracks and therefore reduction in tensile strength at the top of the slope. The existence of cracks contributes to the post-earthquake infiltration of rainwater slows down the dissipation of excess pore water pressure. Slope instability is ultimately caused by permanent damage due to seismic load or ground motion and secondary damage on account for heavy rainfall. Furthermore, the Plant Reinforcement Technology is put forward to reinforce the slope and satisfactory results are obtained. Therefore, this research provides a theoretical basis to analyze and control slope stability in other similar engineering geology problems.