Analytical and Graphical Methods for the Analysis of Slopes in Rock Masses

Abstract : In this report the methods of analyzing the static stability of rock slopes cut by a three-dimensional network of discontinuities are given. The general use of vector analysis to solve these problems analytically is described and a method utilizing stereonets to solve these problems graphically is also given. For both the graphical and analytical methods the general analysis of slopes cut by one, two, or three sets of discontinuities is presented which can take into account the porepressures acting on the discontinuities and external forces acting on the slope. Detailed examples are given to illustrate both the graphical and vector methods of analysis. The dynamic stability of slopes is also treated in this report. It is shown that the dynamic resistance of a three- dimensional rock slope can be calculated by either the graphic-stereonet method or the analytic vector analysis method. The dynamic resistance can then be used to estimate the movement of the slope under dynamic loading using a procedure given by Newmark (1965). A criterion is then given for determining if the calculated movement of the rock slope is acceptable or harmful.