Application of Rock Mass Characterization for Determining the Mechanical Properties of Rock Mass: a Comparative Study

The results of geotechnical explorations, engineering geological investigation (including laboratory and in situ tests) and field observations have been used, along with borehole logging charts, to obtain the rock mass geotechnical data. Based on the data, the rock mass along the Sabzkuh water conveyance tunnel route was classified by rock mass rating (RMR), Q-system (Q), rock mass index (RMi) and geological strength index (GSI) (3 methods). A new series of correlations were established between the systems based on the data collected from the study area. These relationships were then compared with those reported in the literature, and two new relations were recommended. The classifications were utilized to calculate mechanical properties (rock mass strength and deformation modulus) of the rock mass along the tunnel according to available empirical relations, and to distinguish the upper-bound and lower-bound relations.