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伍毅敏, 李文博, 傅鹤林, 刘敏捷. 季冻区隧道过渡段二衬短周期冻融数值模拟[J]. 岩土工程学报, 2017, 39(10): 1930-1935. DOI: 10.11779/CJGE201710023
引用本文: 伍毅敏, 李文博, 傅鹤林, 刘敏捷. 季冻区隧道过渡段二衬短周期冻融数值模拟[J]. 岩土工程学报, 2017, 39(10): 1930-1935. DOI: 10.11779/CJGE201710023
WU Yi-min, LI Wen-bo, FU He-lin, LIU Min-jie. Numerical simulation of freeze-thaw in short period of secondary lining at tunnel transition section in seasonal frozen area[J]. Chinese Journal of Geotechnical Engineering, 2017, 39(10): 1930-1935. DOI: 10.11779/CJGE201710023
Citation: WU Yi-min, LI Wen-bo, FU He-lin, LIU Min-jie. Numerical simulation of freeze-thaw in short period of secondary lining at tunnel transition section in seasonal frozen area[J]. Chinese Journal of Geotechnical Engineering, 2017, 39(10): 1930-1935. DOI: 10.11779/CJGE201710023

季冻区隧道过渡段二衬短周期冻融数值模拟

Numerical simulation of freeze-thaw in short period of secondary lining at tunnel transition section in seasonal frozen area

  • 摘要: 衬砌、围岩中的反复冻融往往伴随着开裂、剥落等风化作用,传统的防冻理论假定环境年温度正弦变化从而低估了二衬冻融次数。自主开发了一款适应低温环境的温度自动记录仪,对季冻区隧道过渡段衬砌表面温度进行了长期、高频监测。推导了适应复杂初始、边界条件的多层圆筒一维瞬态导热差分方程,通过算例验证了其计算精度。将监测数据作为边界条件代入差分方程模拟了真实衬表温度波动下隧道过渡段二衬冻融过程,并探讨了保温层铺设位置对冻融的影响。结果表明:距衬表约5 cm范围内温度波动剧烈;二衬内部每年会经历一次季节性冻结及若干次短周期冻融;在二衬与初支之间铺设保温层后,短周期冻融循环次数及季节性冻结起、止时间基本不变,而短周期冻融深度有所扩大;在二衬表面铺设保温层能使内部始终处于正温,有利于隧道防冻。

     

    Abstract: Repeated freeze-thaw in the lining and surrounding rock is always accompanied by weathering process such as cracking and spalling. The conventional frost-preventing theory will underestimate the freeze-thaw frequency because of the assumption that the ambient yearly temperature changes as sinusoidal function. A kind of automatic temperature recorder adapting to the low temperature environment is developed, through which the long-term and high frequency monitoring of lining surface temperature at tunnel transition section in seasonal frozen area is carried out. The difference equation for transient heat conduction of multilayer cylinder in one-dimension is also derived, whose calculation accuracy is verified by an example. The freeze-thaw process of lining surface temperature at tunnel transition section in seasonal frozen area is simulated after the monitored data are chosen as the boundary condition in the difference equation, and the impact of position of insulation layer on the freeze-thaw is discussed. The result shows that the temperature of the region fluctuates acutely, where it is shorter than 5 cm from the lining surface. A seasonal freezing and several freeze-thaw cycles in a short period appear in secondary lining inside every year. When the position of insulation layer is located between the secondary lining and the initial lining, the frequency of freeze-thaw cycle in a short period and the start and stop time of seasonal freezing change little, but the influence depth of freeze-thaw cycle in a short period is extended. When the position of insulation layer is located at the secondary lining surface, the inner temperature is always greater than 0℃, which is beneficial to the for frost-prevention of tunnels.

     

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