Jia Jianqing, He Zeqing, Tenorio Victor O
School of Traffic and Transportation, Lanzhou Jiaotong University, Lanzhou, 730070, China.
Department of Mining and Geological Engineering, University of Arizona, Tucson, AZ, 85721, USA.
Sci Rep. 2025 Jan 13;15(1):1816. doi: 10.1038/s41598-024-84767-5.
The thermodynamic properties of frozen soil depend on its temperature state and ice content. Additionally, the permeability coefficient significantly affects both the temperature distribution and water movement. In this study, the dynamic variation of soil permeability coefficient with temperature is considered, the permeability coefficient is defined as a piecewise function with temperature as independent variable, and the hydrothermal coupling equation is established. The freezing process of soil column is simulated by secondary development based on COMSOL software. The calculated outcomes align more closely with the experimental results when accounting for the temperature gradient. Notably, the calculation accuracy improves significantly for soil column heights between 0 and 3 cm and 8 to 15 cm, with a difference of only 0.005. On this basis, taking a road subgrade in a cold region as the background, the temperature boundary conditions of this subgrade are revised according to the conclusion of the 6th research report of IPCC, and the time-varying law and characteristics of its temperature field and moisture field are studied. The results show that the temperature gradient is larger within 2 m depth of the subgrade slope, and the temperature distribution is more uniform beyond 2 m, and there is permafrost. With the increase of subgrade depth, the moisture content of soil first increases, then decreases and finally tends to be stable, reaching the maximum at - 0.5 m, which is 13%.
冻土的热力学性质取决于其温度状态和冰含量。此外，渗透系数对温度分布和水分运移都有显著影响。本研究考虑了土壤渗透系数随温度的动态变化，将渗透系数定义为以温度为自变量的分段函数，并建立了热湿耦合方程。基于COMSOL软件进行二次开发，模拟了土柱的冻结过程。考虑温度梯度时，计算结果与实验结果更为接近。值得注意的是，对于0至3厘米和8至15厘米的土柱高度，计算精度显著提高，差值仅为0.005。在此基础上，以寒冷地区的道路路基为背景，根据IPCC第六次研究报告的结论修正了该路基的温度边界条件，研究了其温度场和湿度场的时变规律及特征。结果表明，路基边坡2米深度范围内温度梯度较大，2米以外温度分布较为均匀，存在多年冻土。随着路基深度的增加，土壤含水量先增加，后减少，最终趋于稳定，在-0.5米处达到最大值，为13%。
