寒区隧道地源热泵型供热系统取热段温度场解析

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。供热系统由取热段、加热段、热泵和分、集水管路组成，可用于隧道洞口段衬砌和排水系统加热。取热段位于隧道中部，获取围岩中的地热能。隧道取热段温度场由热交换管外围岩温度场和热交换管内流体温度场两部分组成。建立考虑衬砌结构和热源的隧道取热段热交换管外围岩传热模型，利用叠加原理、拉普拉斯变换和积分变换相结合的方法获得取热段温度场解析解。基于能量守恒原理建立热交换管内流体传热模型，根据热交换管外围岩温度场，利用迭代法计算热交换管的出口温度。采用反分析的方法确定试验段围岩的综合热物性参数，将理论解与现场试验数据对比分析，其精度满足工程要求。取热段温度场理论解为系统的设计提供理论指导。

TEMPERATURE FIELDS ANALYSIS OF ABSORBING SECTION OF TUNNEL HEATING SYSTEM USING HEAT PUMP IN COLD REGION

In order to prevent freezing damage in cold regions tunnels，tunnel heating system using heat pump was introduced for the first time at Linchang tunnel in Inner Mongolia Autonomous Region of China. The tunnel heating system consists of the heating section，absorbing section，heat pump，collector，and distributor line. This system can be used for heating lining and drainage system in tunnel portal. Absorbing section exacts geothermal energy from the surrounding rock of the central part of the tunnel and consists of surrounding rock outside of the heat exchanger pips and fluid in the pipes. The heat transfer model of surrounding rock is obtained considering lining structure and heat resource. The analytical solution can be obtained using the superposition principle，Laplace transform and finite integral transfer method. The heat transfer model of liquid is based on energy conservation method. Back analysis method is used to determine the thermal physical parameters. The outlet temperature can be obtained by the iterative method. Accuracy of the analytical solution is examined by comparing the calculated results with measured results. It is found that the calculated values well agree with those measured in the field. The results of temperature field theory solutions can provide theoretical guidance for the system dasign.