高海拔严寒地区特长公路隧道保温层铺设长度研究

随着我国西部大开发的不断深入,在高海拔严寒地区规划和修建的隧道工程越来越多,且隧道长度越来越长。洞口段合理的保温层铺设长度是高海拔严寒地区特长隧道抗冻设计与建设的关键问题。目前,我国对高海拔严寒地区特长隧道纵向温度分布规律尚无系统研究,保温层铺设长度多以经验计算或工程类比为主。以G317线雀儿山隧道为例,参考鹧鸪山隧道竣工通车后洞口段现场实测温度数据变化规律,对雀儿山隧道洞口段保温层铺设长度进行分析。结果表明:确定寒区隧道保温层铺设段长度时,特别是对于特长隧道,应考虑隧道内年平均温度的变化以及温度振幅的衰减;按照鹧鸪山隧道的年平均气温和洞内气温年振幅实测数据变化幅度,考虑1.2的安全系数,建议雀儿山隧洞口保温层铺设长度取为900 m。事实上,保温层铺设长度与隧道曲线形式、隧道长度、海拔高度、地热梯度以及隧道交通量、断面、交通模式、通风模式等诸多因素有关,因此,高海拔严寒地区特长隧道保温层铺设长度有待进一步通过现场实测数据进行对比分析研究。

Study on the Insulation Layer Length for a Long Highway Tunnel in the High Altitude and Cold Region

At present,more and more tunnels are built in high-altitude and cold regions in China,to meet the rapid progress of the western development,the design and construction have to consider piecewise prevention.There is no systematic research on the longitudinal temperature distribution law of the tunnel in the high altitude and cold area.The length of insulation layer is determined mainly based on experience calculation or analogy analysis.Chola mountain tunnel was taken as an example and Zhegu mountain tunnel temperature field test data were referenced,the Chola mountain tunnel insulation layer length was discussed.The results show that the length of the insulation layer design of tunnel in high-altitude and cold regions,especially for the super long tunnel,the change of annual mean temperature and the attenuation of temperature amplitude in tunnel should be considered.According to the annual average temperature and the annual temperature amplitude measured data change amplitude,in Chola mountain tunnel entrance set 900 m heat preservation layer length,considering the safety factor of 1.2,can guarantee the entire tunnel surrounding rock in winter without freezing phenomenon.In fact,the length of the insulation layer is related to tunnel length,altitude,geothermal gradient and tunnel section,traffic volume,traffic patterns and other factors,therefore,the high altitude cold area tunnel insulation layer laying length should be further studied.