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Hot-freeze Link Technology and Its Application in Snow Melting and Deicing of Tunnel Portal Section of Sichuan-Tibet Highway
(1 MOE Key Laboratory of Transportation Tunnel Engineering, Southwest Jiaotong University, Chengdu 610031；2 School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031；3 Sichuan Highway Planning, Survey, Design and Research Institute Ltd.，Department of Transportation of Sichuan Province, Chengdu 610041)
Abstract In order to effectively utilize the geothermal water in the fault zone of Qinghai-Tibet plateau passed by Sichuan-Tibet highway, a heat-freeze link technology is developed to deal with snow melting and ice removal of the road surface within the scope of tunnel portal in cold area. Taking the Chola Shan tunnel as the engineering background, a geological investigation and field test are conducted to analyze the causes and characteristics of the geothermal water, the heating capacity of hot spring water is calculated based on the field tests of the temperature, velocity and flow of the hot spring water. Meanwhile, the heat demand for snow melting and deicing is calculated, and the feasibility of the hot-freeze link and its practical application effect are analyzed.The results show that: the accumulated time of snow over 10 cm thick on the road at tunnel entrance is 180 days and the time of dark ice is 210 days due to the effect of climate and topography of the Qinghai-Tibet Plateau. Controlled by the geological tectonism of the Qinghai-Tibet plateau and the northern fault zone, the theoretical calculation of the monthly heat supply capacity of the hot spring group in the tunnel site area of Chola Shan tunnel is 7.627×107-1.320×108 kJ. With Chapman model and heat-transfer model of fluid in heat exchange pipe of concrete, a calculation is conducted, and the monthly required heat supply capacity is 3.3×106 kJ and 8.25×107 kJ respectively in order to meet the requirements of snow melt and deicing of the 100 m long and 8 m wide road surface at the tunnel entrance; in the case of 60% utilization rate, hot spring water can still fully meet the needs of snow melting and deicing in the coldest month; hotfreeze link technology is developed by using hot spring water, hot spring water is rich in heat reserves and the height difference can ensure the flow and flow rate, thus pumping equipment is unnecessary and electric energy is saved,and the remained water can be reused due to high temperature. The field temperature test shows that the actual application effect of road snow melting and deicing is good.
Abstract：
In order to effectively utilize the geothermal water in the fault zone of Qinghai-Tibet plateau passed by Sichuan-Tibet highway, a heat-freeze link technology is developed to deal with snow melting and ice removal of the road surface within the scope of tunnel portal in cold area. Taking the Chola Shan tunnel as the engineering background, a geological investigation and field test are conducted to analyze the causes and characteristics of the geothermal water, the heating capacity of hot spring water is calculated based on the field tests of the temperature, velocity and flow of the hot spring water. Meanwhile, the heat demand for snow melting and deicing is calculated, and the feasibility of the hot-freeze link and its practical application effect are analyzed.The results show that: the accumulated time of snow over 10 cm thick on the road at tunnel entrance is 180 days and the time of dark ice is 210 days due to the effect of climate and topography of the Qinghai-Tibet Plateau. Controlled by the geological tectonism of the Qinghai-Tibet plateau and the northern fault zone, the theoretical calculation of the monthly heat supply capacity of the hot spring group in the tunnel site area of Chola Shan tunnel is 7.627×107-1.320×108 kJ. With Chapman model and heat-transfer model of fluid in heat exchange pipe of concrete, a calculation is conducted, and the monthly required heat supply capacity is 3.3×106 kJ and 8.25×107 kJ respectively in order to meet the requirements of snow melt and deicing of the 100 m long and 8 m wide road surface at the tunnel entrance; in the case of 60% utilization rate, hot spring water can still fully meet the needs of snow melting and deicing in the coldest month; hotfreeze link technology is developed by using hot spring water, hot spring water is rich in heat reserves and the height difference can ensure the flow and flow rate, thus pumping equipment is unnecessary and electric energy is saved,and the remained water can be reused due to high temperature. The field temperature test shows that the actual application effect of road snow melting and deicing is good.
YAN Jian1,
2 WEI Yanqing3 HE Chuan1 ZHOU Zihan1 GOU Hao1
.Hot-freeze Link Technology and Its Application in Snow Melting and Deicing of Tunnel Portal Section of Sichuan-Tibet Highway[J] MODERN TUNNELLING TECHNOLOGY, 2020,V57(5): 1-9
2020, Vol. 57 