HEAT TRANSFER ANALYSIS OF SURROUNDING ROCKS WITH THERMAL INSULATION LAYER IN HIGH GEOTHERMAL ROADWAY

A mathematical model of heat conduction in surrounding rocks of the high geothermal roadway with thermal insulation layer was established in this paper, and its finite difference scheme was also proposed. On this basis, thermal insulation mechanism of thermal insulation layer was investigated. Results show that distinct regional temperature distribution exists in the thermal insulation layer. The temperature is continuous while the temperature gradient has a sudden fluctuation at the interface of different media. The wall temperature is lower and the inner surrounding rock temperature is higher in surrounding rocks with thermal insulation layer compared to that in surrounding rocks without thermal insulation layer. Moreover, the smaller the thermal conductivity of the medium in the thermal insulation layer, the larger the temperature gradient and the smaller the heat flux density. At the beginning of ventilation, thermal insulation of the gunite layer is better than that of the grouting layer. After three months, thermal insulation of the grouting layer is better than that of the gunite layer. Thermal insulation layer can reduce 29-40% of heat dissipation and the thermal insulation would be more significant if the thermal insulation layer was constructed earlier.