STABILITY OF JOINTED ROCK MASSES EVALUATED BY UDEC WITH AN EXTENDED SAEB-AMADEI CONSTITUTIVE LAW

This paper discusses the results of a numerical study which examines t he influence of the choice of joint constitutive model on the stabilit y of jointed rock masses. In the two-dimensional code of the Distinct Element Method used for this study, UDEC, the mechanical behaviour of rock joints is represented by an elasto-plastic law and the empirical continuous-yielding law. The modified version of the Saeb and Amadei n on-linear model for rock joints subjected to monotonic and cyclic load ing sequences as proposed by Souley et al. Int. J. Rock Mech. Min. Sci . & Geomech. Abstr. 32, 101-109 (1995), is implemented in UDEC. Two si mple examples provided a verification of the implemented model. These involved the monotonic normal compression of a joint and the direct sh ear test. The influence of joint constitutive law on the stability of an underground cavity was then examined for a specific joint network g eometry. This analysis involved in situ low, medium, and high stress f ields. Interpretation of the results shows that while stress magnitude s depend little on the type of constitutive law, the displacement fiel d is, on the contrary, constitutive law dependent, particularly at hig h stress levels.