ABSTRACT
Indeed, on many underground construction and mining projects, rock mass classifications have provided the only systematic design in an otherwise haphazard trial-and-error procedure. However, modern rock mass classifications have never been intended as the ultimate solution to design problems, but simply a means towards this end. Rock classifications can be broadly divided into two categories, i.e., Intact classifications and mass classifications. Presently Rock Quality Designation is used as a standard parameter in drill core logging and forms a basic element of the two major rock mass classification systems, i.e., the rock mass rating (RMR) and the Q-system. The RMR system, also known as the Geomechanical Classification, was proposed by Z. T. Bieniawski. To apply the classification, the rock mass along the tunnel route is divided into a number of structural regions, i.e., zones in which certain geological features are more or less uniform in the region.
