Engineering properties of fissured rock

The deformability and strength of a rock mass are affected by the hardness and fracturability of the rock constituents, as well as by the number and orientation of joints and fractures in the rock. It is standard practice to classify rock according to these characteristics in order to estimate the engineering properties of the rock. It is difficult, however, to judge rock by these characteristics because the characteristics vary significantly within a given rock formation. Frequently, one or two of these characteristics are sufficiently pronounced to exert a predominant influence on the engineering properties of the rock.