地铁隧道围岩内温度分布规律的模型试验及其热导率反算研究

为能精确计算地铁隧道围岩内的传热量,模拟了地铁隧道围岩内的热传导,研究了地铁围岩内的温度分布规律,并通过试验结果对土体热导率进行反算。分析表明:同一时刻,距隧道壁面不同距离处的温度以指数形式进行变化,距离越远,温度越小;时间越久,隧道内流体的温度影响范围越大。除隧道外壁面外,距隧道壁某距离处的温度,随时间的增长而逐渐增长,距隧道壁较近处土体温度较高,温度增长速率随时间的增长而逐渐减小;距隧道壁面距离较远处温度较低,其增长速率随时间的增长而逐渐增大。传热时间超过某一值后,围岩内温度增长率逐渐平稳趋于一定值。根据模型试验结果能较精确得到土样的热导率数值。

Model test on temperature distribution in metro tunnel surrounding rock and inverse calculation of its thermal conductivity

Heat transfer in surrounding rock of metro tunnel is a large proportion of the entire metro tunnel heat system. To get the accurate heat load of surrounding rock, the heat transfer in metro tunnel is simulated and the temperature distribution is studied through model test. And the inverse calculation of rock thermal conductivity is also given. It is indicated that the temperature decreases with the distance from metro tunnel wall, and follows the exponential law at the same time. And the influencing area of heat fluid in metro tunnel extends with time. The temperature at a distance from metro tunnel wall increases with time. At the closer distance the temperature is higher and the rate of temperature rise decreases with time; and the change rule of farther distance is opposite. Gradually the temperature growth tends to a certain value when heat transfer for more than a certain time. Finally, the precise rock thermal conductivity is also given.