Stress transfer in soil under freezing and thawing of the overlying layer

Abstract

In vast areas with frozen ground, the surface soil layer undergoes freezing and thawing with the changing seasons, which impacts the stress distribution in the underlying soil layers. However, there is a lack of systematic experimental and theoretical research on the stress transfer in this process, which makes the current calculations and analyses incapable of reflecting genuine stress conditions in cold regions. In this paper, a model test system was designed to conduct research on the stress transfer law during freezing and thawing of the overlying soil layer. According to the test conditions, a suitable soil pressure sensor was selected and carefully calibrated. A constant load was applied onto the top soil layer which undergoes freezing and thawing, and stress in the underlying soil was measured. During the freezing process, the frozen zone occurred and continuously developed downwards. Coinciding with the evolution, an attenuation and outward diffusion of the stress field was observed. When thawing started, a non-frozen zone developed from the top down, leaving a sandwich frozen zone progressively decreased over time. The stress field within the soil is partitioned by the presence of the frozen zone. After transit through the frozen zone, there is a significant decrease in stress within the upper non-frozen stratum, which is then transferred to the lower non-frozen stratum.