Assessment of water inrush vulnerability from overlying aquifer using GIS-AHP-based 'three maps-two predictions' method: a case study in Hulusu coal mine, China

摘要

The vulnerability of coal seams C2, C3 and C6 to water inrush from their overlying aquifers is evaluated in the first mining area of Hulusu coal mine. Detailed geological and hydrogeological data are collected for a hydrogeological conceptual model of water inrush. An index model of water abundance of the overlying aquifers is constructed using a geographic information system and the analytic hierarchy process, resulting in a zoning map of water abundance. Comparison of the numerically calculated height of the induced fracture zone above mining areas with the thickness of the overlying strata between the coal seam and the overlying aquifer leads to a connectivity map, which indicates whether the fracture zone is connected to the overlying aquifers. Superimposition of the two zoning maps leads to a comprehensive vulnerability zoning map of overlying aquifer water inrush. Visual Modflow is used to predict the mine discharges from the overlying aquifers under both natural and mining conditions. Appropriate prevention and control measures against overlying aquifer water inrush are proposed on the basis of the comprehensive vulnerability map.