Methods suitable for slopes in soil like materials, where the strength of the material can be determined from testing small specimens of the material in a laboratory. Classical soil mechanics slope stability analysis and material strength testing methods are applicable.
Methods suitable for slopes in hard jointed rock where the stability of the slopes is controlled by the discontinuities in the rock material. Slope stability is evaluated using traditional techniques such as joint surveys to determine the orientation, continuity spacing and strength properties of the jointing and some laboratory strength testing on representative joints and gouge materials. Because of its high strength, little failure occurs through intact rock material. The potential for failure is dependent on the presence, orientation and strength along joints.
Methods suitable for weak rock masses, where failure can occur both through the rock mass, as a result of a combination of macro and micro jointing, and through the weak rock material. Determination of the strength of this category of rock mass is extraordinarily difficult since the size of representative specimens are too large for laboratory testing and the combinations of micro and macro jointing, rock alteration and hard and soft zones is too complex for detailed determination and analyses. Strength estimation for such rock masses is usually based on some form of classification technique.