(1. Department of Geotechnical Engineering，Tongji University，Shanghai 200092，China；2. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education，Tongji University，Shanghai 200092，China；3. Institute of Geotechnical Engineering，Southeast University，Nanjing，Jiangsu 210096，China；4. China Railway 15 Bureau Group Co.，Ltd.，Luoyang，Henan 471000，China)
Abstract：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.
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2012, Vol. 31 
