陕西关中盆地粉质黏土热物理性质研究

关中盆地浅层地热能资源十分丰富,但目前开采程度仍有待提高。土壤的热物理性质在很大程度上决定了其工程特性,对浅层地热能在开发利用过程中所涉及的基本理论和开发方法等具有较大影响。通过室内试验对西安市、咸阳市、渭南市和宝鸡市范围内的粉质黏土的热物理性质开展研究,对试验数据进行了分析,进而揭示了粉质黏土比热容、导温系数和热导率的宏观变化规律。结果表明: 粉质黏土的热导率为0.82~2.65 W/(m·K),导温系数为0.001 28~0.004 86 m²/h,比热容为0.77~1.53 kJ/(kg·K); 随着含水率的增大,热导率整体呈减小趋势,且数值分布范围缩小; 比热容总体随导温系数的增大而减小; 导温系数随热导率的增大呈线性增大,且相关系数均较高。研究可为工程实践过程中开发利用浅层地热提供一定的理论基础。

Study on thermophysical properties of silty clay in Guanzhong Basin,Shaanxi Province

The shallow geothermal energy resources in Guanzhong Basin are very rich, but the exploitation degree still needs to be improved. The engineering characteristics of soil are determined by the thermophysical properties, which has a great impact on the basic theories and development methods during the development and utilization of shallow geothermal energy. Through the laboratory tests of thermophysical properties of silty clay in Xi'an, Xianyang, Weinan and Baoji, and the analysis of experimental data, the authors revealed the macroscopic variation rules of specific heat capacity, thermal diffusivity and thermal conductivity. The results show that, the thermal conductivity of silty clay is 0.82 to 2.65 W/(m·k), the thermal diffusivity is 0.001 28 to 0.004 86 m²/h, and the specific heat capacity is 0.77 to 1.53 kJ/(kg·K). With the increase of water content, the thermal conductivity shows a decrease trend, and its value range becomes narrow. The specific heat capacity decreases with the increase of thermal diffusivity in general. The thermal diffusivity increases linearly with thermal conductivity, and the correlation coefficients are all high. This research would provide some theoretical basis for the development of shallow geothermal energy in engineering practice process.