Abstract: For the development of frost heave during 1-D freezing process of saturated soil, a separate ice frost heave model is established based on the ice lens growth model of coupled moisture and heat transfer. Average separate pressure of the unfrozen water film is analyzed by applying the thermodynamic theory for liquid layer near a substrate, and it is put forward that when this pressure exceeds the critical pressure of soil strength, new ice lens emerges. The soil structure is divided into active zone and passive zone by the interface of warm end of active lens. The process of active zone is described by the coupled moisture and heat transfer model of ice lens growth, while the passive zone approximately experience a heat conduction process, and then a frost heave model is established. A separate ice growth mode of ice lens is introduced, which is compared with the rigid ice growth mode of ice lens, and the connection between the proposed model and the existing models is expounded. Numerical simulation is conducted by using the finite volume method, and comparison is made with Konrad’s three tests. The numerical results of temperature field and frost heave are in general agreement with the experimental ones.