祁连山隧道洞内空气及围岩温度场分析

为了探究寒区隧道洞内空气及围岩温度场设计问题,以世界上海拔最高的高原冻土隧道-祁连山隧道为研究对象,建立非稳态的隧道温度场模型,采用变量控制法探讨不同时间、距离以及有无保温层条件下寒区隧道洞内空气和围岩温度场的变化规律。研究结果表明:当洞外气温为-16.77℃,围岩地温为5℃条件下,祁连山隧道单侧防寒保温长度应该大于1 770m;当洞外气温为-16.77℃,围岩地温为5℃,计算时间为10 d条件下,5 cm厚的聚酚醛保温板保温效果很好,可以保证不出现冻害;当洞外气温为-16.77℃,围岩地温为5℃,当计算时间超过30 d,有保温层时距离进口10 m处隧道初支和二衬范围内出现负温,说明保温层具有一定的适用范围,并不能完全消除寒区隧道的冻害问题。

Analysis on Air of Tunnel in Qilian Mountain and Temperature Field of Surrounding Rock

_{: In order to explore the design of air and surrounding rock temperature field in the tunnel of cold region, taking the highest altitude plateau permafrost tunnel-Qilian Mountain Tunnel as the research object, the unsteady tunnel temperature field model is established, and the variable control method is used to explore the variation law of air and surrounding rock temperature field in the tunnel in the cold zone under the condition of different time and distance. The results show that when the temperature outside the cave is 16.77 DEC, under the condition of 5 DEC, the thermal insulation length of the single side of the tunnel in the Qilian Mountain should be greater than 1 700 m; When the outside temperature is -16.77 DEC, the surrounding rock temperature is 5 DEC, the calculation time is 10 days, 5 cm thick poly-phenolic insulation board insulation effect is very good, can guarantee no frost damage; When the temperature outside the hole is -16.77 DEC, the geothermal temperature of the surrounding rock is 5 DEC, when the calculation time exceeds 30 days, the heat insulating layer has a negative temperature in the initial branch of the tunnel and the two lining range of the inlet, which indicates that the insulation layer has certain applicable range and can not completely eliminate the frost damage of the cold zone tunnel.}