季冻区隧道过渡段二衬短周期冻融数值模拟

发布时间：2019-03-18 15:46

【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]:The repeated freeze-thaw in the lining and surrounding rock tends to be accompanied by weathering, such as cracking, peeling and the like, and the traditional anti-freezing theory assumes that the annual temperature of the environment changes so as to underestimate the number of freeze-thaw cycles of the two liners. An automatic temperature recorder is developed to adapt to the low-temperature environment, and the surface temperature of the lining surface of the tunnel transition section of the seasonal freezing zone is long-term and high-frequency monitoring. A one-dimensional transient thermal differential equation for multi-layer cylinder with complex initial and boundary conditions is derived, and its calculation accuracy is verified by an example. The monitoring data is substituted into the difference equation as the boundary condition to simulate the two-lining freeze-thaw process of the tunnel transition section under the temperature fluctuation of the real lining table, and the influence of the laying position of the heat-insulating layer on the freeze-thaw is also discussed. The results show that the temperature fluctuation is severe in the range of about 5 cm from the surface of the liner, and one seasonal freezing and several short-period freeze-thaw cycles are experienced in the second liner. After the heat-insulating layer is laid between the second liner and the primary branch, the number of freeze-thaw cycles and the seasonal freezing of the short period are almost the same. And the freezing and thawing depth of the short period is expanded; and the heat preservation layer is paved on the two lining surfaces, so that the internal part is always in the normal temperature, and the anti-freezing of the tunnel is facilitated.
【作者单位】：中南大学土木工程学院;五邑大学土木建筑学院;
【基金】：国家自然科学基金项目(51008308,51478473,51578550,51538009)
【分类号】：U457.2

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