Landslides are frequent in the Nanpeng River fault zone in southwest Yunnan. Based on a Zhen Qing Expressway survey, the geological conditions and characteristics of landslides in this area were studied. The conclusions are as follows: 1) the geological background was the internal cause of local highly steep slopes and broken rock masses. The main landslide types in study area are fault-type and accumulation landslides. 2) The formation of fault-type landslides is related to endogenous causes, such as tectonic movements, but they are less easily triggered than accumulation landslides. Accumulation landslides are related to broken rock masses and are sensitive to external factors such as rainfall and artificial unloading. 3) The coordinated control of permanent support engineering, local deformation control, and overall support reinforcement should be considered as preventive measures.

Slipping-stretching landslides have long been recognized as a common type of landslide case, but such reactions have rarely been reported. There was a slipping-stretching landslide reaction at Liangtianao, Guangxi Province, China, and the geological background and deformation characteristics of the case were identified by detailed geological survey and long-term monitoring. A FEM model of the case was built using GEO5 to analyze the mechanism of reaction and deformation. The results are as follows. 1) The Liangtianao landslide is a bedding rock ancient landslide, which remained in a creeping state after the landslide occurred in geological history. 2) The new sliding surface in the Liangtianao landslide is basically consistent with the weak interlayers formed by ancient landslides, and the fault-type is a slipping-stretching type with the following deformation process: strain at leading edge by road excavation→ leading edge instability→ middle part shear and creep→ back edge tensile. 3) Micro-geomorphology, rock mass bedding, and weak interlayers are internal causes of the Liangtianao landslide reaction, while excavation unloading and rainfall are the external causes. The inclinometer indicates that the Liangtianao landslide is still highly sensitive to rainfall after the landslide reaction, which may trigger a secondary landslide reaction. 4) The numerical analysis results indicate that the maintenance of a passive state in the anti-sliding section is highly beneficial to maintaining basic stability after the landslide reaction; unloading only 1/20 of the sliding section makes the landslide stable in the long term.