季节性冻土区隧道保温层御寒保温技术研究

Study on Thermal Insulation Technology of Insulation Layer of Tunnels in Seasonal Frozen Soil Area

为了满足交通的便捷和时效性,我国修建在寒区的隧道工程越来越多。针对困扰季节性寒区隧道工程的冻害问题,以季冻区桦皮岭隧道为依托,开展寒区隧道保温层御寒保温技术研究。首先,开展现场环境温度和竖直钻孔隧道洞口段围岩温度场变化监测,获得计算模型所需精准温度荷载及地表活动层围岩温度场受影响范围;其次,建立基于Fluent流体计算软件的"围岩-衬砌-保温层-空气"气固耦合计算模型,并通过对比现场地勘资料验证计算模型的合理性;最后,对不同保温材质、不同铺设厚度和铺挂方式进行了对比分析。结果表明:围岩温度场随外界大气温度呈近似三角函数周期变化,但"滞后效应"明显;地表活动层围岩温度受影响范围约为8 m;设置保温层处内外温度存在"跳跃"现象,内外温差最高达8℃;硬质聚氨酯保温材料较聚酚醛泡沫塑料和泡沫玻璃御寒保温效果分别提高了近20.6%和80.9%;最优保温层厚度为5 cm,最优铺挂方式为衬砌内表面铺设。

In order to achieve the convenience and timeliness of traffic,more and more tunnels have been built in cold area of our country. According to the problems of seasonal frost damage in tunnel engineering in cold area,this thesis studies tunnel cold insulation based on Huapiling Tunnel in seasonal frozen zone.Firstly,monitoring of field ambient temperature and the temperature of the vertical borehole surrounding rock are carried out,and the exact temperature load and temperature range of the surrounding rock layer are obtained. Secondly, based on the fluent fluid calculation software, the calculation model of＂surrounding rock-lining-insulation layer-air＂is established,and the correctness of the model is verified by comparing the field survey data. Finally,the paper compares and analyzes the different insulation materials,different laying thickness and paving method. The results show that the temperature field of the surrounding rock is similar to that of the atmospheric temperature,but the＂hysteresis effect＂is obvious;the influence of surrounding rock temperature on surface active layer is about 8 m; the phenomenon of＂jump＂exists in the internal and external temperature of the insulation layer,and the temperature difference between inside and outside is as high as8 ℃; Compared with phenolic foam and foam glass, the effect of polyurethane insulation material on heat preservation is increased by20. 6% and 80. 9% respectively; the optimum insulation layer thickness is 5 cm,and the optimallaying method is inner surface lining.