岩溶山区浅层基岩滑坡失稳机理研究——以大方县金星组滑坡为例

A study of the instability mechanism and investigation methods of shallow bedrock landslides in karst mountain areas: taking the Jinxing landslide in Dafang County as an example

岩溶山区浅层滑坡具有发育规律性差、前期变形迹象小、面小点多等特征,早期识别难度大,难以实现全面调查与监测,因此,对典型案例的成因机理进行研究具有重要意义。2016年7月1日贵州省大方县金星组发生滑坡,共造成23人死亡。金星组滑坡滑体厚度平均仅为4 m,总方量约9.5×104m3,属于典型的岩溶山区浅层基岩滑坡。研究认为,坡角大于岩层倾角的顺层坡体结构是滑坡发生的主要内在因素,而滑坡发生前的降雨入渗且无有效的排泄途径,导致坡体中的薄层泥岩发生泥化是金星组滑坡发生的直接触发因素。

Shallow landslides in karst mountain areas are characterized by the poor development rule, small early signs, and small deformation, etc. Early identification for this kind of landslides is difficult and it is also difficult to achieve a comprehensive survey and monitoring. Examination of the formation mechanism is of important significance and can provide theoretical support for the early identification and prevention of landslides. On July 1, 2016, a landslide occurred in the Jinxing Group in Dafang County of Guizhou Province, killing 23 people. The average thickness of the landslide mass is only g m, and the total amount is about 9. 5 × 10^4m^3. The landslide belongs to a typical bedrock landslide in karst mountain areas. The research results show that the slope angle larger than the dip angle of the bedding slope structure is the main internal factors of the landslide. The landslide occurred before the rainfall infiltration and there was no effective excretion pathway, resulting in thin layers of mudstone in slope, which directly triggered the occurrence of the landslide.