关键词: 边坡, 土石混合体, 人工降雨模拟试验, 降雨入渗, 现场监测

Abstract: Rainfall and its infiltration into a soil-rock-mixture slope is one of the most important factors affecting slope stability. The problem of soil-rock-mixture slope instability caused by rainfall has been paid close attention by people all the time, but the study on this problem not enough systemic and thorough. In order to improve our understanding of the fundamental mechanism of rainfall infiltration induced landslides in soil-rock-mixture landslide and to clarify some of important characteristic of slope performance, artificial rainfall simulation tests and field synthetic monitored method were carried out on a typical soil-rock-mixture slope in Guizhou province near Shangrui Freeway. The monitored results demonstrate that the deformed zone of soil-rock-mixture landslides caused by rainfall infiltration lies within the top 0~4 m soil layer, where the deformation value of slope surface is the biggest, which gradually reducing from dome to the deep part of slope. The average percentage of infiltration during the first 2 hours is 86 %, it reduces gradually with time later because of the increase of the surface runoff. The average percentage of infiltration drop to a relatively stable value (50 %) 6 hours later. Rainfall infiltration leads pore-water pressure to increase, which may result in a reduction of shear strength due to a decrease in effective stress and wetting-induced softening. The double effects of rainfall infiltration are the main reasons of rainfall infiltration induced landslides in soil-rock-mixture slope.