冻融环境下拉脊山隧道防寒保温设计

Cold Insulation Design of Lajishan Tunnel in Freeze-Thaw Environment

拉脊山隧道为高海拔高寒特长公路隧道,隧址区极端最高温28.7℃,极端最低温-37℃,隧道进口最大冻土深度为1.60 m。在严寒地区冻融环境下的隧道极易出现冻害现象,情况严重会直接影响隧道使用。本文在分析隧道冻害现象和常见的处理措施基础上,通过计算分析,得出隧道周围冻融圈的深度与所采用的保温层的类型和厚度以及不同岩体孔隙度之间的变化规律,根据计算结论和工程经验对拉脊山隧道进行防寒保温设计,相关措施可供类似隧道参考。

Lajishan tunnel is an extra-long highway tunnel in high altitude and cold zones, with extremely high temperature 28.7% and extremely minimum temperature -37℃. The maximum depth of frozen soil of tunnel entrance is 1.60 m. Tunnels prone to frost damage phenomena in freeze-thaw environment, which seriously affects the use of the tunnel. This paper analyzes the tunnel frost damage and its common measures, on which basis we get the depth of freeze-thaw circle and the corresponding type and thickness of thermal insulation layer, variation between the different rock porosity through calculation and analysis. Cold insulation design for Lajishan tunnel has been conducted according to the calculation results and engineering experience. Some related measures can be served as reference for similar tunnels.