Frost-heaving may triggered the catastrophic landslide in Zhenxiong on January 22, 2024
摘要
Landslides occurring under low-temperature conditions in winter with spatio-temporal unexpectedness can result in significant losses of human life and property. At about 5:51 a.m. on January 22, 2024, a landslide disaster occurred in Liangshui Village, Zhenxiong County, Yunnan Province, China, resulting in 44 deaths. This study analyzes the characteristics and discusses the disaster’s mechanism using a combination of on-site investigation, drone aerial survey, remote sensing interpretation, InSAR analysis, and numerical calculation. The results show that (1) the landslide in Zhenxiong was relatively small in volume, approximately 118,800 m3, but with significant consequences of 44 fatalities; (2) the regional factors such as geology, geomorphology, meteorology, and hydrology are conducive to the development of landslide disasters. The landslide occurred near the top of the steep slope with a height difference of 250 m and was in the form of a “boot-shaped terrain.” The lithology of the area consists of siltstone and mudstone of the Triassic Feixianguan Formation, and the vertical joints of the rock body have cracked up to 1.4 joints per meter; (3) before the landslide occurrence, the slope was in a critical state with extensive development of cracks, and a large number of these cracks were parallel and perpendicular to the ridge. The ratio of historical weathering sections in the stone blocks in the accumulation area is more than 60%. InSAR results show that the landslide source area has been undergoing continuous creeping subsidence since 2020, with a maximum displacement rate of − 61.31 mm/yr; (4) three factors contributed to the slope’s freeze-up and destabilization: the catchment at the slope’s back-end, the sandstone-mudstone interlayer’s geology, and the sustained low temperature before the landslide. The low-temperature frost-heaving effect may finally trigger the landslide. Considering the frost-heaving force, the factor of safety of the block was 0.99, and a landslide debris flow with a high-speed rate of 40.09 m/s was formed after the block was destabilized. This type of geological disaster in winter is highly unexpected and requires great attention.