关键词: 石炭系梓山组, 炭质页岩, 滑坡机理, 防治措施, 数值模拟, 强降雨

Abstract: The Carboniferous Zishan Formation（C1z）carbonaceous shale rock group is widely dis⁃ tributed in the central and southern Jiangxi Provinces. The landslides developed there have the character⁃ istics of easy slip，large scale，strong destructiveness and difficult prevention and control. On July 14， 2019，a medium-sized landslide with a scale of about 30 × 104 m3 occurred in Xiatan Village，Zishan Town，Yudu County，threatening the safety of 178 people in 44 households. In order to explore its forma⁃ tion mechanism and put forward the prevention and control scheme，field investigation，engineering ex⁃ ploration，X-ray diffraction test and GeoStudio numerical simulation were carried out. The results show that the landslide is a traction medium-sized rock landslide induced by heavy rainfall（24 h precipitation 96.2 mm）. The landform is“steep in the upper and slow in the lower，step-like scattered accumulation”. The rock occurrence is 335°∠ 41° ~ 55°，and the landslide area is about 2.07×104 m2 . The differential weathering of carbonaceous shale interlayer in sandstone is the internal main reason，which contains 14.9% montmorillonite and 9.8% kaolinite. The hydrophilic expansion characteristics lead to the decrease of shear strength of rock mass，and the superposition of heavy rainfall and human engineering activities in⁃ duce landslides. In view of the difficulties in treatment，the idea of " lock head + press foot " is put for⁃ ward. The anchor lattice + rubble concrete retaining wall support is adopted to replace the weak stratum （bearing capacity of 40 kPa）of the foundation. After GeoStudio checking，the safety factor of the slope af⁃ ter treatment is 1.58，which meets the requirements of the specification. After two hydrological years of in⁃spection，the effect is good，which can provide reference for the prevention and control of similar land⁃ slides in Gannan area.

Key words: Carboniferous Zishan Formation, carbonaceous shale, mechanism of landslide, prevention measures, numerical simulation, heavy rainfall