Graphical charts for onsite Continuous Slope Mass Rating (CoSMR) classification using strike parallelism and joint dip or plunge of intersection

Abstract

We propose the new continuous slope mass rating (SMR) charts for easy calculation of SMR class of rock slopes in the field. SMR class can be determined by plotting the parallelism between dip directions of slope and discontinuity (slope dip direction and trend direction of intersection line in case of wedge failure) (A) in the x-axis and discontinuity dip amount (βj) (plunge amount in case of wedge failure (βi)) in the y-axis using SMR charts. We apply the proposed SMR charts to an assumed rock slope consisting of four joint sets and a basic Rock Mass Rating (RMRb) value of eighty. SMR class for the assumed rock slope was calculated using proposed SMR charts and by the existing Graphical Slope Mass Rating (GSMR) method. After comparing both the methods, we demonstrate, the proposed SMR charts prove to be simpler and take less time to evaluate SMR class as compared to the GSMR method. The GSMR method requires matching six stereonets for a single rock slope, whereas by using proposed SMR charts minimal use of stereonet is required to calculate trend and plunge of intersection. Proposed SMR charts incorporate the continuous functions (F1, F2, and F3) for SMR calculation, whereas a discrete rating system is used in the GSMR method. This study suggests, the proposed SMR charts are easy to use, more efficient, and can be adopted as a valuable tool for the preliminary rock slope stability assessment in mountainous areas like the Himalayas, where within a few meters joints and slopes geometries changes.