RMR - A system for characterizing rock mass classification: A case study from Garhwal Himalaya, Uttarakhand

In order to understand the importance of rockmass and its properties for stability analysis several classification methods are available. The rock mass rating (RMR) has been found to be quite useful due to the ease with which it can be practiced and based mainly on the collection of field data and strength parameters. This technique has been used earlier in many mining and engineering projects and found useful in an assessment of the slope stability condition and for mining plans and designing the structures. RMR technique involves collection of data on rock strength, RQD (%), spacing of discontinuities, condition of discontinuities and groundwater conditions. Twelve sites selected on the basis of good exposures of the rock outcrops along the road section were studied using RMR approach. The results indicates that the rock mass of this area fall under the good, fair and poor rock quality. The rock type viz. mica schists and phyllites well exposed in the study area have lower RMR ratings, as they are more readily weathered and contain some weak planes and break along these planes. The analysis and evaluation should serve as a guide for engineering development projects in the area.