Numerical Simulation of the Temperature Field and Deformation of Subgrade for Sunny-Shady Slopes in a Seasonal Frozen Region

The second and third types of boundary conditions were mixed to simulate the change rule for the subgrade temperature field under the actual climate condition in a seasonal frozen region. The temperature difference between sunny and shady slopes was also analyzed. The freezing and thawing coefficients were introduced to compute the subgrade deformation caused by temperature differences considering the location and shape of the freezing fringe. Then, the mechanism of subgrade deformation was discussed. Results show the following conditions. (1) When groundwater exists, an uneven horizontal deformation is strongly affected by the temperature difference caused by slopes. (2) The deformations of the shoulder and bottom of the northern slope are greater during the freezing process than during the thawing process, and maximum deformation occurs at the top of the northern slope during the thawing process. Meanwhile, tension damage is likely to appear on both sides of the slope and at the top of the subgrade near the northern slope. Thus, for subgrade design and maintenance in a seasonal frozen region, the northern slope and the shoulder near the northern slope can be treated separately. Different designs and maintenance procedures can be applied to decrease temperature difference.