Classification method of deep rock mass based on FDAHP theory

Based on RMR system, joint space index is removed and insitu stress index is introduced into the classification method for considering deepbury status of rock mass. Hierarchical structure model of deep rock mass classification is constructed, in which the 5 assessment index is respectively the intact rock strength, rock mass integrity (RQD), rock mass joint conditions, groundwater conditions and insitu stress state. The weight of each index is determined by using Fuzzy Delphi Analytic Hierarchy Process method (FDAHP), and classification method of deep rock mass for coal mine based on FDAHP theory is presented. The proposed method and RMR system are applied to deep rock mass at depth of 600～1 000m in the Huainan mining area for a comparative analysis. The results show that rock mass at depth of 600～1 000m in Huainan are mostly threegrade or fourgrade rock mass. The value of the proposed method is less than the value of RMR system, and the maximum value difference is as high as 8 points.