This study aims at revealing the deformation and evolution characteristics

formation mechanism and stability of slope under rainfall infiltration condition. A slope in the north stope of Taihe mine in Xichang city

Sichuan province was analyzed in detail as a research object by adopting various methods such as field geological survey and mapping

in-situ test

laboratory test and numerical simulation. The results show that: 1) Both landslides in 2018 and 2019 occurred in rainy season and stabilized again with the end of rainy season. 2) The formation of the landslide is the result of the comprehensive action of multiple factors: the fault provides the boundary for the formation of the landslide

which is the external condition; the diabase with high content of chlorite and montmorillonite is easy to soften and disintegrate when exposed to water

which is an internal condition; the mining and rainfall are the inducing factors. Mining forms an ultra-high slope and exposes the diabase rock layer

while rainwater infiltrates from the slope surface and fault to erode and soften the whole diabase rock layer

resulting in local sliding of the diabase layer under the action of high potential energy

and then pulling it to the overall sliding. 3) Rainfall greatly impacts on the factor of safety and failure mode of slope. The slope is in a stable state before rainfall

and the potential failure mode is overall sliding. After 5 days of rainfall

the factor of safety for the slope drops to 0.842

and two steps of local sliding occurs in the diabase layer. After that

the factor of safety continues to decrease

and the damage range further expands

which is confirmed by the actual observations.