The freeze-thaw cycle poses a significant threat to foundations and roadbeds in seasonally frozen regions. This article conducts model experiments to analyze changes in the temperature field, water migration patterns, and settlement deformation characteristics of sand-gravel replacement foundations during freeze-thaw cycles. The experimental findings indicate that the low-temperature zone primarily exists within the sand-gravel replacement layer at the base of the slope. As the number of freeze-thaw cycles increases, the freezing depth of the sand-gravel replacement layer continues to rise. During the cooling phase, changes in soil volume moisture content result from self-weight and water migration during freezing. With an increase in the number of freeze-thaw cycles, the moisture content of external measurement points on the embankment rises at the end of the freezing period, whereas the moisture content of internal measurement points decreases. At the end of the thawing phase, measurement point 6 experiences an increase in moisture content due to the upward migration of water in the lower soil layer, while other measurement points exhibit reduced moisture content. The foundation's settlement deformation exhibits a horizontal tilted shape, with cumulative settlement amounts and settlement deformation rates determined at various positions. These results suggest that the settlement deformation tends to stabilize one month after the completion of embankment filling construction. The maximum freezing depths at the left and right slope toe positions are 1 m and 1.2 m, respectively. Furthermore, the maximum frost heave at the slope toe position is less than the maximum thawing settlement, illustrating the irreversible soil deformation following freeze-thaw cycles.

Energy piles are highly favored for their excellent, low energy consumption in providing heating for public residences. The temperature field changes the activity of the diffuse double electric layer (DEL) on the particle surface, thereby altering the distribution of the stress field in the soil and ultimately affecting the mechanical properties of the interface between the energy pile and the soil. Therefore, studying the influence of water content on the mechanical behavior of the soil-structure interface in the temperature field is crucial for energy pile safety. This study used a modified temperature-controlled direct shear apparatus to obtain the influence of water content and temperature on the shear behavior of the soil-structure interface. Then, the test results were analyzed and discussed. Finally, three results were obtained: (1) The water content of bentonite (wbent) had a significant impact on the shear stress-shear displacement curve of the soil-structure interface; when the wbent was less than the wp of the bentonite, the tau-l curve exhibited a softening response, then displayed a hardening response. (2) The shear strength of the soil-structure interface gradually decreased with the increase of wbent. (3) The shear strength of the soil-structure interface increased with increasing temperature under various wbent and vertical loads.

In cold regions, the freezing and thawing of embankments often cause significant damage to road surfaces. Research indicates that this freeze-thaw process is closely related to the distribution of temperature and moisture within the embankment. Therefore, an in-depth study of the moisture and temperature conditions and the resulting deformation under freeze-thaw effects is fundamental for analyzing crack-related diseases inAroad surfaces. The authors have developed a monitoring system for moisture and temperature in cold region highway embankments to conduct long-term observations. Based on the collected data, the distribution patterns of moisture and temperature fields in the embankment were analyzed. The results indicate that temperature changes at different locations within the embankment generally correspond to atmospheric temperature changes, exhibiting a periodic sinusoidal pattern. The annual variation in embankment temperature shows a nonlinear negative correlation with depth.

The formation of pores due to the spontaneous combustion of coal in the goaf, as well as the damage to the surrounding rock caused by high-temperature roasting, can lead to surface subsidence and even collapse. In addition, incomplete combustion of coal can result in the production of various harmful gases, which may escape into the atmosphere through these cracks and seriously pollute the air. This pollution can exacerbate topsoil subsidence, degrade soil properties, harm surface vegetation, and contaminate surface water and groundwater. As a solution to these issues, liquid carbon dioxide fire prevention and extinguishing technology are being utilized for theoretical analysis of overburden movement in goaf. A three-dimensional distribution model of porosity in caving areas has been constructed. Based on this model, dynamic changes in temperature field and oxygen concentration field during liquid carbon dioxide perfusion are being explored. The rapid vaporization of liquid carbon dioxide into inert gas within the goaf inhibits coal oxidation and heating by forming an inert belt within its diffusion range. Simulation results indicate that injecting liquid carbon dioxide at a 90 degrees angle into the oxidation zone (where oxygen concentration is 7-12%) at a volume of 750 m3h-1 best balances cost considerations with effective injection in mining goafs. Industrial testing has shown that after 65 h of perfusion, CO gas concentration decreased from 790ppm to 41ppm - proving significant fire prevention effects from liquid carbon dioxide application.

Hydro -thermal coupling is the essence of the freeze -thaw process, and theoretical studies of this coupled process have been hot topics in the field of frozen soil. Darcy's law of unsaturated soil water flow, heat conduction theory, and relative saturation and solid -liquid ratio are based on this paper. According to the principle that the cumulative curve of particle gradation of canal foundation soil is similar to soil -water properties. A soil -water characteristic curve is derived using the cumulative particle gradation curve. VG model is then used to fit soil -water characteristic curves to obtain the canal foundation soil's hydraulic characteristic parameters, and the established hydro -thermal coupling model is modified to reflect canal foundation soil hydro -thermal evolution more objectively. A closed system one-way freezing test method is used to verify the feasibility of the proposed method in this part. The results show that the optimal parameters of the VG model of the subsoil are a = 0.06, n = 1.2, and m = 0.17, and the temperature and water fields obtained from the simulation are in good agreement with the measured data, showing the utility of the hydro -thermal coupling model in predicting hydraulic parameters. Analysis of the multi -field interaction mechanism and dynamic coupling process of the canal foundation soil during freezing and thawing. This has great importance for preventing freezing damage in canals and protecting agricultural safety.

Long-distance pipelines may pass through areas of frozen soil sometimes, such as the Trans-Alaska pipeline and the Chinese Northeast pipeline. This work intends to analyze the performance of buried pipeline under reverse fault motion in such regions. A pipe-soil system model was established, and the thermo-mechanical coupling analysis was carried out. The temperature distribution of the soil near the ground and around the pipe is affected by them apparently, especially by ground. For the true temperature field (TTF) and the simplified one (STF), the pipe strain peak value and developing laws differ hugely, because of different soil mechanical properties distribution. The peak strains of the pipe are the largest at +0 degrees C of the ground, and the local buckling of the pipe appears earlier than the tensile failure. TTF should be obtained, and the peak compressive strain at +0 degrees C should be taken as the main criterion for seismic design or check calculation, for compressive bearing capacity usually determines pipe mechanical properties.

The thermal parameters of adherent layer are of great significance to the distribution characteristics of temperature field and foundation stability control of runway in permafrost region. This paper investigated the effects of annual range of temperature (A), annual average temperature (T-A), and other factors on the adherent layer thickness (H), temperature amplitude (A(0)), and annual average ground temperature (T-0), and further analyzed the thermal parameters of the adherent layer by using the FEM (Finite Element Model) roadbed temperature field and experimental data. The results indicate: A and average monthly total solar radiation (Q) have the most serious on H. A numerical method for determining the parameters of the adherent layer based on various conditions such as A and T-A was proposed by multiple regression. The temperature fields of the three types of pavements obtained by FEM and the experimental data were compared with the numerical calculation results for verification, and the conclusions were in close agreement, illustrating that the proposed method for calculating the parameters of the adherent layer is reasonable and effective. The research results extend the application region of adherent layer theory and provide a reference for runway construction in the permafrost region of Northeast China.