The Effect of Discontinuity Persistence on Rock Slope Stability

l f Discominuity persistence has a major effect on rock mass resistance (strength) but, as direct mapping ofdiscominuities imemal to a rock mass is not possible, persistence is a difficult parameter to measure. As a result, the conservative approach of assuming full persistence is often taken. /n this paper a method is developed for relating rock mass stability and hence persistence to the geometry and spatia/variability of discontinuities. The method is applied to slope stability ('alculations ill which the probability offailure is related to discominuity data, as obtained in joim surveys. The complete method makes use of dynamic programming and simulation, but a closed form expression satisfactory for most purposes is also presemed.