Coupling Model And Simulation Of Soil Heat-Moisture-Stress In Cold Regions

In cold regions soil experienced a freezing and melting process in a year, moisture, temperature and stress coupled and acted in the process. As soil freezing, the moisture moved, ice-water changed in phase, raised ice and frost heave continuously happened, the coupled heat-moisture-stress was very complicated and hard to research. However for the roads, bridges, pipes and constructions in cold regions, required to determine their soil's temperature, stress and displacement. So the research on coupled heat-moisture-stress action in soil freezing and melting process was of great significance to simulate moisture-heat movement, grip freezing and melting laws and prevent soil frost heave.In this paper firstly analyzed the basic nature of soil in freezing and melting process, identified moisture movement, heat conduction, latent heat of phase change should be considered in soil moisture-heat coupling immigration equation when simulated soil temperature. As the ice in frozen soil resisted the moisture movement, need to consider ice resistance coefficient. The water-heat coupling move equation was as control equation, simultaneously unfrozen moisture content and most unfrozen moisture with temperature equations, the heat exchange between the air and the ground and constant zone of subsurface temperature of soil for the borders, took soil natural temperature field as initial condition, the soil moisture-heat coupling temperature model was constructed. Numerical solution was carried out, the obtained results show that:comparing with not consider phase or ice resistance temperature curve, considering these roles the temperature curve is not smooth cosine curve, the freezing and melting processes change slow in temperature, and the melting process is longer than the freezing process. Comparing with the experiment data of soil temperature, the results show that:considering phase change and ice roles the numeric results coincide with the experiment data better. Through numeric solution, thermal conductivity, temperature diffusivity, ice's impacts on temperature field were simulated. And as the increase of soil or as the decrease of thermal conductivity, the gently period lasts longer. The larger of ice content, the melting time longer. On the basis of coupled moisture-heat action research, Took the soil buried pipeline in cold region as example, ANSYS finite element analysis software was applied to explore the frozen ground temperature, and it coupled relation with frost heave, and this play a role to the research on the heave action of frozen soil and to the engineering.