Risk assessment of karst collapse in the Tailai basin based on the synthetic index method

The karst collapse in the Tailai basin began in the 1960s, which has caused increasingly serious economic losses and social impacts. Based on the analysis of the geological conditions, 12 indexes were selected as the assessment factors, including karst collapse influencing factors and social vulnerability factors, thus to establish a risk evaluation system. Then, the weight of each assessment element was calculated using the AHP method, and the classification diagram of each index was drawn and assigned separately. Finally, the risk index was calculated using MAPGIS software, and the risk classification of karst collapse was made according to the criteria. The results show that high-risk areas are mainly distributed in the following areas， (1) Taian City，urban railway station, Zijiaguanzhuang, Dongyang-Jiuxian; (2) Laiwu City， Gushan-Kuhe area of Dawangzhuang Town, and Menggongqing-Quanhe of the iron mining area. These areas are mostly around the water source area or the drainage areas of mining enterprises, where high-intensity pumping groundwater is the most important factor causing karst collapse.