cryostatic pressure

(geology) Hydrostatic pressure exerted on soil and rocks when soil water freezes.

The pressure exerted on rocks and soil when freezing occurs. As the freezing front advances, the pressure of the soil moisture increases since it is trapped. Such pressure can separate individual grains of soil, forming a mass of fluid mud. This may be driven near to the surface where it domes up the ground, or where it forms mud blisters.