Published on February 15 2015

The geologic classification of the rock material is based on origin, mineralogical composition, mineral size and petrologic characteristics.  The condition, i.e. classes of the various features to be used in rock engineering should be easily observed or measured in the field and/or laboratory.

The rockmass contains several features, each of them with properties.  They all play a role in its strength and modulus of deformation.  Many of these features are applied as input to classification systems.  A collection of classifications is presented below:

Classification should provide a common basis of communication, and to identify a rock mass into one of the groups having well defined characteristics and also yield basic input data for engineering design.

The terminology used should be widely accepted by engineers and geologists. Only the most significant properties of the rock should be considered, which will influence the engineering properties and behaviour


Important quotations are presented below from time to time:

"If the art of soil classification is far from satisfactory, the confusion is often made worse in that users are unaware of its limitations and apply it for purposes other than that originally intended".

Arthur M. Casagrande (1948)