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.