Effects of horizontal and three-dimensional reinforcement on frost-heaving and thawing-settlement in seasonally frozen soils

The frost heaving and thaw-induced settlement is the primary causes of structural damage in the areas with seasonally frozen soils. Practical applications have demonstrated that the roadbeds reinforced with geosynthetic materials exhibit excellent resistance to cyclic frost-thaw damage. However, the beneficial effects of various forms of reinforcement have not been quantified. To address this gap, the freeze-thaw cycle tests and plate-load tests are conducted on soil samples, horizontally or three-dimensionally reinforced, collected from a representative seasonal frozen soil site in the Aba area, Sichuan Province. The effects of freeze-thaw cycle on the mechanical properties of the reinforced soil are compared to those of unreinforced soil. Additionally, a comparative analysis of the mitigation effects of frost-heaving, thawing-settlement and bearing capacity is performed between the horizontally and three-dimensionally reinforced soils. The study reveals that the frost-heaving and thawing-settlement in the soils can be effectively mitigated by both the horizontal and three-dimensional reinforcements. Moreover, these reinforcement methods enhance the post-freeze-thaw bearing capacity of the soils and counteract the weakening effects of freeze-thaw cycles. Notably, the three-dimensional reinforcement demonstrates a superior reinforcing effect in comparison to the horizontal reinforcement. Following five freeze-thaw cycles, the horizontal reinforcement results in a 5% reduction in the frost-heave and a 6% reduction in the thaw-induced settlement, while the three-dimensional reinforcement yields a 4% reduction in the frost heave and a 17% reduction in the thaw-induced settlement. The horizontal reinforcement enhances the bearing capacity and stiffness of freeze-thaw cyclic soil by 75% and 29%, respectively. In contrast, the three-dimensional reinforcement significantly improves the bearing capacity and stiffness of the freeze-thaw cyclic soils by 388% and 40%, respectively.