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在考虑并行隧道耦合传热的前提下,预测越江公路隧道江岸浅埋段地温的长期演化,使用有限差分法进行数值模拟,通过现场观测与数值迭代方式确定边界条件与初值.模拟结果表明:最终的计算稳定传热时间为68年,但传热在20年内即基本完成;隧道周围的初始恒温土层最终被转变为年变温土层;隧道外侧5 m及两孔之间出现了一个显著变温区,其最大温升值为7.14℃,最大年度温升的峰谷值为10℃;隧道周围10 m以下土层的温度变化仅由隧道传热所控制;两孔之间土层的最终稳定温度要高于其他位置的最终稳定温度,证实了耦合传热效应的存在.此外,还提出了一组单变量函数的回归模型,用以估计隧道周围不同位置土层的年度温度波动量.该研究将有助于深入探究隧道浅埋段所穿越江滩区域工程地质条件的长期演化趋势.
The long-term evolution of the geothermal temperature in shallow buried section of the riverbank of Vietnam River Tunnel is predicted under the premise of parallel coupled heat transfer in the tunnel. The finite difference method is used to simulate the long-term evolution of the ground temperature and the boundary conditions and initial values are determined by field observation and numerical iteration. The final calculation of the stable heat transfer time is 68 years, but the heat transfer is basically completed within 20 years; the initial thermostatic soil around the tunnel is finally transformed into annual temperature-changing soil; and there is a significant difference between the tunnel 5 m and the two holes In the variable temperature zone, the maximum temperature rise value is 7.14 ℃, and the peak and valley value of the maximum annual temperature rise is 10 ℃. The temperature change of the soil layer below 10 m around the tunnel is controlled by tunnel heat transfer only; the final stability of the soil layer between the two holes The temperature is higher than the final stable temperature of other locations, confirming the existence of coupled heat transfer effect.In addition, a set of regression models of univariate functions are also proposed to estimate the annual temperature fluctuation of soil layers in different locations around the tunnel. The study will be helpful to in-depth study of the long-term evolution trend of the engineering geological conditions of the riverbed crossing the shallow section of the tunnel.