IS 13365 : Part 1 : 2025 Quantitative Classification Systems of Rock Mass - Guidelines - Part 1 Rock Mass Rating (RMR) for Predicting Engineering Properties

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 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. Modified RMR can also be used for predicting the ground conditions for tunnelling.

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.

2 REFERENCES

The standards listed in Annex A contain provisions which through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition of these standards.