Fuzzy comprehensive evaluation of land collapse risk in the Xishan mining area, Beijing

In the Xishan mining area of Beijing，the landform belongs to middle-low mountains, where two Carboniferous and Jurassic coal measures are developed. Coal beds are mined using adits and inclined shafts. After many years of mining, land collapse in the mining area has been of common occurrence and the phenomena are unique. According to the survey data, the authors studied the types and distribution characteristics of the land collapses, used the theory and methods of bipolar fuzzy comprehensive evaluation to establish the risk assessment model and evaluation indicators of land collapse risk and used GIS spatial analysis functions to do land collapse risk zoning in the Xishan mining area of Beijing. The mining area is divided into the risk, relative risk and stable zones. The comprehensive evaluation shows that the risk levels of land collapse are significantly zoned. The distribution of the land collapse risk zone is consistent with that of the mined-out area.