ROCK CLASSIFICATIONS: STATE OF THE ART AND PROSPECTS FOR STANDARDIZATION

The purpose of this paper is to present a state-of-the-art review of rock classifications and to consider the need and prospects for attaining a standard classification. Recent developments concerning both intact-rock classifications and rock-mass classifications are described. Such engineering applications of the current rock-classification systems as tunnels and chambers, slopes, and foundations are discussed, and it is demonstrated how rock classifications enable estimation of the strength and the deformability of rock masses. It is shown that rock-mass classifications are already in existence that include both intact-rock and rock-mass properties and that correlations have been developed among the main classification systems. It is found that there is a distinct need for limited standardization without inhibiting the development or improvement of techniques. There does not seem to be a need for one standard classification that has universal application since the various engineering applications have different classification requirements. (Author)