Time-dependent compression resulting from thawing of Frozen Ground and subsequent draining of excess water. If during thaw, the flow of water from the thawed ground is unimpeded, then the variation of thaw settlement with time is controlled solely by the position of the thawing front. If the thawed ground is not sufficiently permeable, and flow is impeded, however, the rate of settlement with time is also controlled by the compressibility and permeability of the thawed ground. In the case of thawing fine-grained soils, if the rate of thaw is sufficiently fast, water is released at a rate exceeding that at which it can flow from the soil, and pore pressures in excess of hydrostatic will be generated. These excess pore pressures may cause severe instability problems in slopes and foundation soils.