Shear strength of ice-filled rock joints

Ice-filled rock joints are a common feature of high mountain permafrost areas. Warming of these joints in rock can lead to instabilities and rockfall events. In the following study, a series of direct shear tests was performed with artificial samples simulating ice-filled rock joints. The direct shear tests were carried out in two testing modes: constant strain and constant stress. In constant stress tests, the ice-filled joints show a parabolic relationship between normal stress and shear stress unlike the linear relationship usually found in mineral filled rock joints (Barton 1974). Constant stress tests were also conducted in which the samples were allowed to warm up until failure occurred while a constant normal stress and a constant shear test were applied. Different failure modes could be identified, either driven by breaking the connection of ice and concrete or ductile deformation of the ice or a combination of both.