基于多孔介质理论的渠道基土温度场特性研究

发布时间：2019-03-22 14:49

【摘要】：视冻土为均匀各向同性的多孔介质,确定了不同冻结状况下的土壤热参数。根据热传导方程,建立了土壤冻结过程的二维变系数数学模型,通过全隐式差分方法,并采用交替方向差分格式,得到了随时间和空间变化的温度分布场的求解方法。利用土柱冻结解析解验证了数值模型。以整体式小型U形渠道为对象,研究了不同位置及深度的基土温度分布状况,并与野外观测结果进行了对比。结果表明,基于多孔介质理论确定土壤热参数可以简化非线性方程的求解,全隐式交替差分格式对于小型渠道基土求解温度场比较适用;由于渠道区域形状的不规则及其二维边界,导致地下水位、热流对渠道不同部位的温度分布具有不同的作用,阴坡温度普遍低于渠底,已冻区逐渐扩大,温度分布较均匀,正冻区渠道基土温度呈非均匀分布状态。
[Abstract]:Considering frozen soil as homogeneous isotropic porous medium, soil thermal parameters under different freezing conditions were determined. Based on the heat conduction equation, a two-dimensional mathematical model of soil freezing process with variable coefficients is established. By using the fully implicit difference method and the alternating direction difference scheme, the method for solving the temperature distribution field with time and space variation is obtained. The numerical model is verified by the analytical solution of soil column freezing. Taking integral small U-shaped channel as an object, the temperature distribution of foundation soil at different locations and depths is studied and compared with the field observation results. The results show that the calculation of soil thermal parameters based on porous media theory can simplify the solution of nonlinear equations, and the fully implicit alternating difference scheme is suitable for solving the temperature field of small channel foundation soil. Because of the irregular shape of the channel area and its two-dimensional boundary, the underground water level and heat flux have different effects on the temperature distribution in different parts of the channel. The temperature of the overcast slope is generally lower than the bottom of the canal, the frozen area is gradually enlarged, and the temperature distribution is more uniform. The temperature distribution of channel foundation in normal freezing area is non-uniform.
【作者单位】：宁夏大学;
【基金】：国家自然科学基金项目(51269023)
【分类号】：TV223;TV672

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