Rock slope design using slope stability rating (SSR) - Application and field verifications

Abstract

SSR (Slope Stability Rating) classification system is a new rating system which has been proposed in Iran to study the stability of fractured rock slopes of non-structurally controlled failures. In this system, the stability can be evaluated by means of slope design charts. In this study the system is reviewed using 46 slope cases from Iran and Australia. Using the above mentioned design charts, the recommended stable angle for each slope was compared with the current slope conditions. This comparison showed that, in the design charts, increasing of stable excavation angle by slope height reduction is partly large in the cases that the height of slope is less than 100 meters. In addition the design curves overestimate stable design angle especially for flatter slopes. As a result of this work, the modified SSR system rock slope design charts for maximum excavation angle (FS=1.0) and also for some conservative excavation angles (FS=1.2, 1.3, 1.5) are presented.