A PHOTOELASTIC STUDY OF ICE PRESSURE IN ROCK CRACKS

Water was frozen in a slot made in a transparent material, and the resulting stresses in the material produced by the expansion of the ice were measured by use of the photoelastic effect. The maximum water pressure was 11 bar. A theory is presented which accounts, in outline, for the observed stresses, and its implications for freezing in real rocks are discussed. The physics of freezing water confined in a rock crack is different according to whether the ice does or does not begin to extrude. In our experiment there was some extrusion, and in this case the pressure can be calculated simply from the known yield strength of ice, the elasticity and strength of the rock not being directly involved.