Abstract: The resettlement of residents in the nearest possible areas is always applied in the Three Gorges Reservoir region, China. But engineering disturbances and heavy rainfall often induce the landslide instability. This paper discusses the impact factors and formation mechanism of the Jinjiling landslide in Jiangdong district, Wushan county, Chongqing, China. It shows that the cutting and filling of slopes lead to loading of the trailing edge and removal of material from the leading edge. More importantly, the filling of channels with surface soil blocks the surface water discharge channel along the landslide body, promoting the transformation of surface water into groundwater. Therefore the groundwater level in the Jinjiling landslide rose substantially under heavy rainfall, resulting in a large deformation on approximately August 1, 2018. After emergency treatment, including groundwater pumping from the landslide body, the landslide deformation slowed considerably. It is analyzed that the groundwater rise caused by filling of the landslide body is the key factor of the landslide. The numerical simulation shows that the stability coefficient of the engineering decreases obviously after the disturbance of engineering, and the seepage field in the corresponding filling area changes obviously. The seepage is intensified, characterized as the increase in the pore water pressure, hydraulic gradient and total water head. Based on Darcy's law and principle of effective stress, the increase of seepage force and decrease of shear strength induce landslide deformation.

Key words: Three Gorges Reservoir region, slope engineering, Jinjiling landslide, formation mechanism, numerical simulation