基于流体力学、传热学和空气动力学的基本原理与方法,推导出考虑通风影响的寒区隧道围岩温度场模型,该模型包括:围岩温度场控制方程、隧道内风温场控制方程以及风流场湍流控制方程。在此基础上,采用数值分析方法探讨西藏嘎隆拉隧道通风条件下围岩温度场的变化规律及其防寒保温措施。研究结果表明:隧道未开挖前,随着季节的变化,山体浅部温度出现明显变化,该变化较明显的深度为18 m,当岩体埋深大于18 m后,岩体温度随季节的变化幅值小于0.5℃;隧道贯通后,由于通风影响,在环境温度最冷月(1月),隧道进出口段一定范围内的围岩温度出现了0℃以下的不利工况,进一步研究显示:在嘎隆拉隧道进口端600 m和出口端400 m范围内,二衬表面敷设6 cm厚的聚酚醛保温材料,可以有效地防止嘎隆拉隧道衬砌和围岩发生冻融破坏。
Based on the basic principle and method of fluid mechanics, heat transfer and dynamics of air, a cold temperature field model is deduced. The impact of surrounding rock tunnel ventilation is considered in this model. This model includes: temperature control equations of surrounding rock, air temperature field control equations in tunnel and wind flow control equations of turbulence field. On this basis, numerical analysis method is used to discuss the temperature field change law of surrounding rock and thermal insulation measures of Galongla tunnel in Tibet under the condition of ventilation. The study results show that: before tunnel excavation, there is a clear temperature fluctuation in the shallow mountain changing with the change of season and the apparent change appears at the depth of 18 m. When rock depth is more than 18 m, the temperature fluctuation amplitude of rockmass with the change of season is less than 0.5℃. Due to ventilation effect, the temperature of surrounding rock presents the adverse conditions of below 0 ℃ within the scope of inlet and outlet sections of tunnel at the most coldest month(January) after the breakthrough of tunnel. Further research shows thats, at the inlet section of 600 m and outlet section of 400 m in Galongla tunnel, heat preservation material such as phenolics with the thickness of 6 cm is laid on secondary lining surface, which can effectively prevent the Galongla tunnel lining and rock from freeze-thaw damage.