Angouran mine access tunnel stability assessment using the experimental classification method and fuzzy hierarchical analysis (FAHP)

Zanjan Angaran lead and zinc mine access tunnel with the length of 1133 meters has been excavated for underground extraction at a level of 2700 meters with an existing cross section of 7.5 square meters. The tunnel cross-section is to be increased to 20 square meters in order to access the trucks for cut and cover extraction. In this study, while studying tunneling and underground space stability methods, the stability conditions of Anguran mine access tunnel were investigated empirically, fuzzy hierarchical analysis. In the experimental method, while classifying rock masses by Q, RMR and GSI methods using Q classification results, two types of reinforcement were introduced, due to their greater conformity with the region, with 80% tunneling of type 2 with 2cm shotcrete and rockbolts with 2.5 meters length and 2.5 meters spacing. According to the same conditions in the empirical classification parameters using fuzzy hierarchical analysis, as a multilayer information analytical criterion based on the amount of overburden, RQD index of rock, spacing, rock and water strength in defined tunnel stability and weighting to layers and overlap In Arc GIS environment, a hazard zoning map is presented in the tunnel, which according to the map of the end of the tunnel has the highest risk of instability.