It is known that frost heave pressure goes through the process of initiation

development and dissipation when rock cracks under freeze-thaw cycles. Moreover

both the frost extension of cracking and the degree of frost damage of rock depend on frost heave pressure. Therefore

an analytical model is established for frost heave pressure in an idealized cylindrical closed crack

based on the theory of thermodynamics

seepage mechanics

interfacial mechanics and elastic theory. Besides

the effect of moisture migration on the value of frost heave pressure is investigated. Without considering the moisture migration

the results show that the frost heave pressure increases rapidly with the increase of water saturation in crack and rock elastic modulus Es. Under the condition of and 94%

the frost heave pressure exceeds 15 MPa

which is high enough to drive rocks to initiate cracking. In addition

the rock starts to crack once the water saturation reaches its own critical value

. For rocks with the low permeability below 5×10?14 cm2

a high frost heave pressure can be produced by frozen water in the crack

which easily leads to frost crack propagation. However

for rocks with the permeability above 10?12 cm2

the frost heave water pressure could not cause any damage. The main reason for crack frost propagation in high permeability rock is the disjoining pressure in a microscopic unfrozen water film between ice and rock interface after water frozen.