3.1 Introduction

Slope failures are major natural hazards that occur in many areas throughout the world. Slopes expose two or more free surfaces because of geometry. Plane, wedge, toppling, rockfall and rotational (circular/non-circular) types of failure are common in slopes (Figure 1). The first four are more predominant in rock slopes and are primarily controlled by the orientation and the spacing of discontinuities planes with respect to the slope face.  The pattern of the discontinuities may be comprised of a single discontinuity, or a pair of discontinuities that intersect each other, or a combination of multiple discontinuities that are linked together to form a failure mode. Circular and non circular failure occurs in soil, mine dump, heavily jointed or fractured rock mass and very weak rock. The types of slope failure are primarily controlled by material properties, water content and foundation strength.

        Figure 1: Common types of slope failure