地铁隧道围岩传热规律的监测分析

地铁隧道,由于其封闭性,在使用过程中所产生的大量热量要靠环控系统来排除,而围岩传热量的准确估算对环控系统热负荷的确定以及热环境控制都有着重要作用。但是目前隧道围岩传热的规律尚不明确,缺乏科学可靠的预测评价,因此,本文对南京地铁1号线典型地铁隧道区段的隧道空气温度、壁面温度和壁面热流进行了现场实测。实测结果分析表明,隧道壁面温度与热流变化的主要诱因是运行车辆发热,地面气温的剧烈变化也是重要因素之一;同时也表明在典型条件下地铁隧道围岩壁面温度和热流随地表气温变化,壁面热流呈现日周期变化规律。最后,本文基于列车实际运行参数,初步估算了典型地铁隧道区段列车运行的总产热量,以及围岩传热量占总产热量的比例。

Monitoring and Analysis of Heat Transfer through Surrounding Rocks of Subway Tunnel

Subway tunnels are almost isolated from the outside air.Air conditioning system is usually needed to extract the large amount of heats during the operation of subway.The estimation of heat transfer through surrounding rocks is a basis for the determination of heat load of air conditioning system and the control of thermal environment.However,the estimation and prediction of heat transfer is difficult and not satisfactory so far.Therefore,some monitoring instruments were installed in a section of the tunnel of Nanjing subway line 1.The air temperature in tunnel,tunnel wall surface temperature and heat flow have been monitored.The monitoring data show that the heat generated by running trains is the upmost factor for the change of tunnel surface temperature and heat flow through surrounding rocks.The surface temperature of subway tunnel and heat flow through surrounding rocks can be affected significantly by dramatic change of ground temperature.Heat flow through surrounding rocks showed a clear cyclical change within a day.Finally,on the basis of the actual operation parameters,the total heat generated by a train was calculated,and then the ratio of the heat transfer through surrounding rocks of the monitoring tunnel has also been estimated.