寒区隧道围岩初始温度场及保温材料对非稳态温度场的影响

EFFECT OF SURROUNDING ROCK’S INITIAL TEMPERATURE FIELD IN COLD REGIONS AND THERMAL INSULATION MATERIAL ON UNSTEADY TEMPERATURE FIELD

本研究利用商用模拟软件FLUENT,分别使用非稳态初始条件和均温初始条件,对寒区隧道围岩内温度场随时间的变化特性进行了模拟仿真,表明隧道围岩的初始温度场分布对准确模拟寒流导致的围岩温度分布有重要影响。分析了不同保温层材料对隧道围岩结构温度分布的影响,由于三种保温材料的热导率均比较小,5 cm厚保温层后的围岩温度相差不大,但是5 cm厚保温层不足以保证所依托隧道结构不发生冻害;需要根据寒区隧道的气象条件铺设主动加热带,从而有效防止冻害现象的发生。

The variation characterization of the temperature field with time in the tunnel surrounding rock was simulated by using FLUENT,including two initial conditions as the unsteady and uniform temperature field.The results showed the initial temperature field had an important influence on the accuracy of the simulation results.Since the thermal conductivity of the three insulation materials is relatively small,the temperature difference after 5cm insulation layer was not very obvious.However,the 5cm thick insulation layer was not enough to guarantee the structure away from freezing damage.Therefore,it was necessary to lay a heating zone according to the weather conditions to prevent the occurrence of freezing damage.