ABSTRACT
A fairly common engineering failure is slipping of an embankment or cutting, and considerable research has been carried out into the causes of such failures. Water is frequently the cause of earth slips, either by eroding a sand stratum, lubricating a shale or increasing the moisture content of a clay, and hence decreasing the shear strength. When a slip in a clay soil occurs it is frequently found to be along a circular arc, and therefore this shape is assumed when studying the stability of a slope. This circular arc may cut the face of the slope, pass through the toe or be deep-seated and cause heave at the base (see Fig. 85). Prediction of the most likely failure plane relies heavily on experience, based on the study of past cases.
