IS 13365 : Part 1 : 1998 Quantitative Classification Systems of Rock Mass - Guidelines - Part 1 : Rock Mass Rating (RMR) For Predicting Engineering Properties

ICS 93.020                                                   CED48

Reaffirmed 2021

1 Scope

This standard (Part 1) covers the procedure for determining the class of rock mass based on geomechanics classification system which is also called the Rock Mass Rating (RMR) system, The classification can be used for estimating the unsupported span, the stand-up time or bridge action period and the support pressures of an underground opening. It can also be used for selecting a method of excavation and permanent support system. Further, cohesion, angle of internal friction and elastic modulus of the rock mass can be estimated. In its modified form RMR can also be used for predicting the ground conditions for tunneling.

It is emphasized that recommended correlations should be used for feasibility studies and preliminary designs only. In-situ tests are essential for final design of important structures.