A GRAPHICAL-METHOD FOR THE CLASSIFICATION OF ROCK AND WEAK ROCK MASSES BASED ON FIELD OBSERVATIONS

Weak and weathered rock masses are not described effectively by tradit ional classification systems, These systems do not account for time de pendent changes in strength, nor are they universally applicable to ro cks of differing strengths or weathering mechanisms. This engineering classification system for rock and weak rock masses considers three fa ctors that control the overall strength of rock bodies: compressive st rength, nature and density of discontinuities, and decrease in strengt h over engineering time, Measurements of these three factors are condu cted using simple field observations and then a particular rating is a ssigned to the rock mass for each property, The strength, discontinuit y and rate of change in strength ratings are then plotted in a three-d imensional manner that allows for the visual comparison of rock masses and their anticipated engineering behaviors.