Research on hydrothermal process of subgrade in transition section of fill-cut under dual action of freeze-thaw and dynamic load

Abstract

The subgrade built in the permafrost zone is not only affected by temperature changes, but also by the upper vehicle loads. And, there will be differences in the deformation of the subgrade of the fill-cut transition section under the dual action of freeze-thaw (FT) and dynamic loading. The hydrothermal evolution of the subgrade under the dual action of FT and dynamic loading is investigated by model tests. The test found that at the 15th freeze-thaw cycle (FTC), a high-moisture content zone appeared in the soil parallel to the fill-cut transition section, and the distribution of pore water pressure (PWP) was similar to that of the moisture zone. And the soil in the high-moisture content zone causes significant settlement on the soil surface. By comparing with the subgrade of the fill-cut transition section after 15 cycles under the freeze-thaw action, it was found that the dynamic load would change the distribution of moisture and PWP of the subgrade of the fill-cut transition section, and then affect the displacement of the soil and produce an restrain effect on the soil frost heaving.