Characteristics of caprock-karst combination in typical karst collapsearea along the Yangtze River in Anhui Province

Along the Yangtze River area in the Anhui Province (Tongling, Chizhou, Anqing), karst collapse geological disasters are developed.Whether it is to prevent and control geological disasters in karst collapse or to monitor and early predict, it is important to study the geological environment conditions of karst collapse and grasp the engineering geological characteristics of caprock, karst development characteristics of underlying carbonate rocks and the relationship between caprock and karst. This paper takes along the Yangtze River area in the Anhui Province karst collapse as research area. Based on comprehensive collection and collation of investigation and monitoring data of the karst collapses and field investigation in typical karst collapse area, the characteristics of caprock engineering geology and underlying carbonate karst were analyzed. Through conceptualization, geological model of the cap rocks together with underlying karst were established. Research results shows that there are 7 types of capping layer and karst combinations in the typical karst collapse area of which the most vulnerable to karst collapse is the type of the quaternary cover with silty clay and sandy gravel double-layer structure, and underlying medium karstified bedrocks. The mechanism of karst collapse is mainly submersible erosion induced collapse, followed by vacuum erosion induced collapse and vibration collapse.