Mesomechanical Analysis Of Rock Thermo-mechanical Properties

With the development of ultra-deep geological drilling,geothermal exploration and development,nuclear waste disposal and other fields,it is urgent to carry out research on the physical and mechanical properties of rocks under the coupled effect of thermo-mechanical multi-fields.In this paper,considering the heterogeneity of different mineral compositions of rocks,the effective thermal expansion coefficient,effective thermal conductivity and effective specific heat of rocks are studied in detail using the knowledge of mesomechanics,and the influence of porosity is discussed in detail.Select sandstone,slate,and granite as the research objects.The results are as follows:(1)The thermal expansion coefficient of each mineral component is proportional to the temperature.When the temperature rises,the effective thermal expansion coefficient of the rock shows an overall upward trend;in the range of 100°C to 500°C,the porosity has little effect on the effective thermal expansion coefficient of the rock,which is not considered.(2)The thermal conductivity of each mineral component is inversely proportional to temperature.When the temperature increases,the effective thermal conductivity of the rock decreases.At the same temperature,the thermal conductivity of air is much smaller than that of diagenetic minerals.Therefore,when the porosity increases,the effective thermal conductivity of the rock decreases.(3)The specific heat of each mineral component is proportional to the temperature.When the temperature increases,the effective specific heat of the rock increases.At the same temperature,if the specific heat value of air is lower than the solid phase components,when the porosity increases,the effective constant volume specific heat of the rock will decrease;and vice versa.