Calculation Method of Interface Contact Thermal Resistance between Rock and Lining in High Rock Temperature Tunnels Considering the Lithology

Abstract

The disasters caused by the high rock temperature are increasingly prominent. To accurately assess the temperature at the rock-lining interface in high rock temperature tunnels, the rock thermal conductivity evaluation coefficient was introduced to propose a method for calculating interface contact thermal resistance that accounts for the influence of the surrounding rock lithology. This method, based on a disc model, offers precise insights into the thermal resistance between the surrounding rock and the tunnel lining. To validate the efficacy of this method, initial numerical simulations and subsequently performed laboratory experiments across various rock-concrete interfaces were conducted. Laboratory experiments reveal that the interface contact thermal resistance between rock and concrete specimens tends to decrease as temperatures rise from 20°C to 80°C. Moreover, a substantial increase in interfacial contact thermal resistance was observed when dealing with higher-grade surrounding rock (indicating lower quality), reaching up to 111.24 %. The maximum relative error observed in the results of the calculation method is 8.64 %, well within the acceptable range of 15 %, confirming its reliability and practicality for engineering applications. These research findings can serve as a valuable reference for designing support structures in high-temperature rock tunnels and advancing disaster prevention and mitigation technologies.