Study on water–heat coupling migration law and frost heave effect of soil slope in seasonal frozen regions during groundwater recharge.

To study the law of water–heat coupling migration and the frost heave deformation characteristics of soil slopes in seasonal areas under groundwater recharge conditions, this paper constructs a water–heat–stress coupling model considering moisture migration, ice–water phase change, ice resistance, and frost heave effects based on COMSOL modelling software. Then, numerical simulation results are compared with the experimental results to verify the effectiveness of the multi-field coupling model. The results show that the slope temperature change has an evident lag compared with the ambient temperature change. The shallow soil of slopes changes dramatically under external ambient temperature, while the deep soil gradually tends to the ground temperature under the geothermal influence. The slope temperature distribution rules are basically the same in different groundwater recharge levels. The maximum freezing depth of the slope is deeper at a high groundwater level. When the groundwater level is high, the total moisture content of the slope is larger, and the thawing area may be saturated or oversaturated in the spring thawing period. For unsaturated soil slopes in seasonal freezing for a long time, the total moisture content of slopes tends to increase slightly after each freeze–thaw cycle due to groundwater recharge. The problems of slopes in seasonal frozen areas are manifested by the frost heave of the soil at the top of slopes, which may cause frost heave damage. When the groundwater level is high, the maximum horizontal displacement of the slope surface and the frost heave deformation at the top of slopes increase greatly. [ABSTRACT FROM AUTHOR]