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Study on the Temperature Field and Insulation Layer Thickness of the Yuximolegai Tunnel
(1 Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation, Shandong University of Science and Technology, Qingdao 266590; 2 State Key Laboratory For Geomechanics & Deep Underground Engineering, China University of Mining& Technology, Xuzhou 221116)
Abstract The Yuximolegai tunnel on the G217 national highway in Xinjiang is located in a high-altitude seasonal frozen-ground region. In order to ensure its safe operation, it is necessary to study its temperature field and determine a proper insulation layer thickness. An automatic temperature monitor was used to obtain temperature variations at different radial depths of the Yuximolegai tunnel. Based on the calculating parameters determined by laboratory tests, the model boundary conditions were determined by fitting the analytical results of field temperature monitoring. The temperatures obtained by field monitoring were compared with those determined by the temperature field calculation without an insulating layer, and their changing tendencies are basically in agreement. Further analysis was conducted on the reliability of the 5 cm-thick insulating layer used in the field, and the calculations show that there is a freeze scope of 0.4 m behind the lining wall. The expanding law of the freezing front was analyzed and results indicate that the freezing front expands fastest and for the farthest distance on the spandrel and bottom, where the most dangerous positions on the whole cross section are. Ultimately, the required thickness of the insulating lay? er was calculated according to the criteria of whether or not the temperature outside the spandrel and bottom lining layer is 0℃.
Abstract：
The Yuximolegai tunnel on the G217 national highway in Xinjiang is located in a high-altitude seasonal frozen-ground region. In order to ensure its safe operation, it is necessary to study its temperature field and determine a proper insulation layer thickness. An automatic temperature monitor was used to obtain temperature variations at different radial depths of the Yuximolegai tunnel. Based on the calculating parameters determined by laboratory tests, the model boundary conditions were determined by fitting the analytical results of field temperature monitoring. The temperatures obtained by field monitoring were compared with those determined by the temperature field calculation without an insulating layer, and their changing tendencies are basically in agreement. Further analysis was conducted on the reliability of the 5 cm-thick insulating layer used in the field, and the calculations show that there is a freeze scope of 0.4 m behind the lining wall. The expanding law of the freezing front was analyzed and results indicate that the freezing front expands fastest and for the farthest distance on the spandrel and bottom, where the most dangerous positions on the whole cross section are. Ultimately, the required thickness of the insulating lay? er was calculated according to the criteria of whether or not the temperature outside the spandrel and bottom lining layer is 0℃.
FENG Qiang- 1 Liu-Wei-Wei- 1 Jiang-Bin-Song- 2
.Study on the Temperature Field and Insulation Layer Thickness of the Yuximolegai Tunnel[J] MODERN TUNNELLING TECHNOLOGY, 2016,V53(5): 78-84
2016, Vol. 53 