Stress in Rock Slopes: Non-persistent Versus Persistent Joint Model

Abstract

In rock slopes prone to topple, mechanical, physical or chemical weathering might degrade the rock mass properties and compromise the stability of that rock slopes. However, the nature of the joints distribution and the degree of continuity is extremely important in determining the stresses magnitude and sign inside the rock masses. This is mainly due to the stress concentration and distribution near the joint tips inside the rock slope if rock bridges exist. In this paper, a man-made rock slope is numerically modeled and investigated under two types of joint sceneries; out-dipping persistent joint and non-persistent joint models. One point, near the crest, inside the rock slope were used to monitor and measure the major and minor principal stresses as the excavation at the toe of the slope progressed step by step. To generate the two models, the discrete element method with the Voronoi tessellation joint pattern was utilized. One of the advantages of this modeling approach is that it al-lows for generating non-persistent joint as well as persistent joint patterns inside the rock slope. The results of this numerical study show that in large rock slopes such as the one examined in this study, the stress concentration in the non-persistent model is three to four times larger than the stresses at the same point in the persistent joints model. The minor principal stresses in both modeling cases were negative tensile stresses and up to several MPa in magnitude.