Risk assessment of floor water inrush in coal mines based on secondary fuzzy comprehensive evaluation

A secondary fuzzy comprehensive evaluation system is constructed to evaluate the risk of floor water invasion in coal mines. Four first-grade indices and 13 second-grade indices are determined based on the principles of scientificity, rationality, operability and representative by using fuzzy mathematics theory. Each index is quantitatively graded according to five risk grades using fuzzy statistical method and expert evaluation method, and the membership degree of every index is constructed. The weight of every index is rationally distributed by analytic hierarchy process (AHP). Evaluations of engineering practice are carried through with hydrogeological data of six mining faces in China. The satisfying evaluation results are consistent with engineering practice. (C) 2012 Elsevier Ltd. All rights reserved.