The effect of rise in mean annual temperature on the stability of rock slopes containing ice-filled discontinuities

Direct shear box tests have revealed that the stiffness and strength of an ice-filled joint are a function of both normal stress and temperature. Comparison of these data with the results of similar experiments conducted on unfrozen joints indicates that at low temperatures and normal stresses the strength of an ice-filled joint can be significantly higher than that of an unfrozen joint. However, in the absence of sufficient closure pressure, the strength of an ice-filled joint can be significantly less than that of an unfrozen joint. This implies that if the stability of a slope is maintained by ice-filled joints, its factor of safety will reduce with temperature rise. This hypothesis suggests that a jointed rock slope that is stable when there is no ice in the joints and is also stable when ice in the joints is at low temperatures will become unstable as the ice warms. Results from the model tests have confirmed this hypothesis. Copyright (C) 2001 John Wiley St Sons, Ltd.