Stability charts for simple earth slopes allowing for tension cracks : Cousins, B F Proc 3rd Australia-New Zealand Conference on geomechanics, Wellington, 12–16 May 1980, V2, P101–105. Publ Wellington: New Zealand institution of Engineers, 1980

Abstract

In a previous paper by the author (Cousins, 1978) stability charts were presented for simple earth slopes ignoring tension cracks. Tension cracks are usually the first sign of impending failure in cohesive soils and therefore should be taken into account. In this paper the effect of tension cracks both dry and filled with water is investigated. Stability charts are presented for toe circles with no water in the tension crack and for a homogeneous pore pressure ratio r = 0, 0.25 and 0.5. A chart is also given for pore pressure ratio r = 0 with the tension crack filled with water. The charts have been constructed assuming the worst possible location and depth of the tension crack. As such they represent a lower bound for the safety factor. The maximum reduction in safety factor of 40% was found for slope angle a = 60degrees and dimensionless parameter lambda = 20 with the tension crack filled with water. For most cases the reduction was much less than this.