Comments on Modulus Ratio and Joint Factor Concepts to Predict Rock Mass Response

Excerpt

The use of modulus ratio and joint factor (Ramamurthy et al. 2017) to predict rock mass response is an interesting concept. The formulation of joint factor invoked a keen interest among the field engineers ever since originally proposed by Arora (1987), Ramamurthy and Arora (1994), Arora and Trivedi (1992), Trivedi and Arora (2007) and modified by Ramamurthy (2004) to correlate this concept with GSI. The example of several slope failures indicates that the failure surface is often well oriented. It exhibits the importance of preexisting joint-induced sliding in jointed rock mass despite very significant intact rock strength. The evaluation of rock mass strength has been historically based on empirical observations of cumulative visible strain history appearing in the form of fractures, discontinuities and joints. The authors have presented an interesting account on the empirical correlation of joint factor with GSI, RMR and Q systems for the rock masses. Accordingly, the authors have used these observations to access compressive strength (σ _cj), modulus (E _j), cohesion (c _j) and friction angle and to predict stress–strain response of rock mass. …