Evaluation method and application of water-rich of clastic rock aquifer in mining seam roof

Abstract Clastic rock aquifer of the coal seam roof often constitutes the direct water-filling aquifer of the coal seam and its water-rich is closely related to the risk of roof water inrush. Therefore, the evaluation of the water-rich of clastic rock aquifer is the basic work of coal seam roof water disaster prevention. This article taked the 4th coal seam in Huafeng mine field as an example. It combined the empirical formula method and GRNN neural network to calculate the development height of water-conducting fracture zone, determined the vertical spatial range of water-rich evaluation. Depth of the sandstone floor, brittle rock ratio, lithological structure index, fault strength index, and fault intersections and endpoints density were selected as the main controlling factors. A combination weighting method based on the Analytic Hierarchy Process (AHP), Rough Set Theory (RS), and Minimum Deviation Method (MD) was proposed to determine the weight of the main controlling factors. Introduced the theory of unascertained measures and confidence recognition criteria to construct an evaluation model for the water-rich of clastic rock aquifers, the study area was divided into three zones: relatively weak water-rich zones, medium water-rich zones, and relatively strong water-rich zones. By comparing with the water inrush points and the water inflow of workfaces, the evaluation model's water yield zoning was consistent with the actual situation, and the prediction effect was good. This provided a new idea for the evaluation of the water-rich of the clastic rock aquifer on the roof of the mining coal seam.