Abstract：According to the basic laws of water movement and heat migration about rock mass under the freezing- thawing cycle condition，based on the theory of continuum mechanics，thermodynamics and segregation potential，the coupled equations of seepage field and temperature field are established. This model can not only consider the influence of thermal conduction，latent heat and seepage velocity on the distribution of temperature，but also analyze the effect of water flow induced by segregation potential on the seepage velocity and seepage pressure. To verify the reliability and rationality of the equations，the comparison is done by using the same conditions between the model test which was done by M. Smith and the finite element analysis using this coupled mathematical model. Then the model is applied to a cold regional tunnel，and the distribution of temperature and active ring of permafrost are obtained. The results can give some references for design and construction of tunnel in cold regions.
