A Preliminary Study of Joint Effect of Earthquake Disturbing and Rainfall On Yiliang Landslide

Earthquakes and subsequent rainfall infiltration often easily trigger a landslide, such as the "10.4" Yiliang slope incident in Yunnan Province. In the present study, based on detailed on-site survey, indoor rainfall tests were designed to investigate the different hydraulic responses of initial and seismic slopes to rainfall. To further assess the joint effects of earthquake disturbance and subsequent rainfall on slope failure, the rainfall unsaturated seepage fields of the above two types of slope were simulated separately. Then, based on the pore water pressures obtained in the above calculations, the safety factors of the slopes were calculated using a finite element method. The results showed that the seismic slopes are inclined to rainfall infiltration, which significantly increased the pore water pressure and induced the rise of ground water. Moreover, the factor value of seismic slope safety suffering subsequent rainfall was shown to be smaller than the undisturbed one. Finally, a deeper potential failure zone and wider soil mass sliding range evidently illustrated the combined effect of earthquakes and rainfall on the triggering of slope failure.