寒区隧道地源热泵型供热系统岩土热响应试验

ROCK-SOIL THERMAL RESPONSE TEST OF TUNNEL HEATING SYSTEM USING HEAT PUMP IN COLD REGION

为解决寒区隧道冻害问题,将地源热泵型供热系统应用于内蒙古博牙高速林场隧道中。通过开展寒区隧道地源热泵供热系统岩土热响应试验,研究热交换管管内循环介质的入口温度、流量和管间距对换热量的影响以及热交换对隧道围岩和衬砌温度场的影响。试验结果表明:管内循环介质的流量一定时,换热量随着入口温度的增加而呈线性增加;管内循环介质的入口温度一定时,换热量随着流量的增加而呈指数增加。增加流量可以提高热交换管内循环介质的换热能力,但却增加管内循环介质与管壁之间的阻力,建议热交换管管内循环介质流量不宜超过0.75 m3/h。热交换管间距为100和50 cm时,围岩温度场的影响深度分别约为75和100 cm。热交换管间距越小,围岩温度场的影响范围则越大,温度增量也越大。

In order to prevent freezing damage of tunnels in cold region, tunnel heating system using heat pump was introduced for the first time at Linchang tunnel in Inner Mongolia Autonomous Region of China. The rock-soil thermal response test was carried out to study the influence of the inlet temperature, flow rate and pipes distance on extracted heat and the influence of heat exchange on temperature field of surrounding rock and primary lining. It can be found that the extracted heat varies with the inlet temperature linearly and with flow rate exponentially. Although the extracted heat can be improved by increasing the flow rate, there is more resistance to fluid in heat exchange pipes, it will be uneconomical if the flow rate is great~ it is suggested that the flow rate is no more than 0.75 m3/h. The affected depth of surrounding rock temperature is 75 cm when the heat exchange pipes distance is 100 cm, and is 100 cm when the heat exchange pips distance is 50 cm. The less the heat exchange pipes distance, the greater the affect depth of surrounding rock temperature and the temperature increment.