基于圆形断面的隧道温度场有限差分计算模型

Finite Difference Calculation Model for Tunnel Temperature Field Based on Circular Cross-section

除了少数圆形隧道外,大部分山岭交通隧道断面采用马蹄形或端墙式等形状。在隧道温度场的预测中,圆形断面模型能否代替马蹄形等实际隧道模型,其适应性值得研究。应用基于空气-衬砌-围岩的对流-导热耦合作用控制方程的有限差分方法,建立圆形断面模型对东北寒区马蹄形隧道温度场进行计算,并与现场实测温度场进行对比。结果表明：1）圆形断面隧道模型有限差分计算方法克服了通用有限元软件建模复杂、对硬件要求高的弊端,考虑了隧道内风流速度和入口风流温度的影响,在隧道温度场的预测计算中能够满足工程使用要求。2）隧道内风流速度和入口风流温度对隧道温度场影响较大。本文算例中,入口风流温度每升高10℃,二次衬砌表面温度升高约7.2℃,增幅均匀;从1~5 m/s,洞内风流速度每增大1 m/s,二次衬砌表面温度降低的幅度为6.6、2.7、1.5、0.9℃,降幅越来越小。

The horseshoe-shaped tunnels and end wall type tunnels are common in mountain areas. It＇s necessary to study the suitability of tunnel temperature field calculation model using circular cross-section. The temperature fields of cold region horseshoe-shaped tunnels in Northeast China are calculated by circular cross-section model using finite difference method of convection-conduction equations based on air-lining-surrounding rock. The calculation results are compared with measured data. The results show that： 1） The finite difference calculation method by using circular crosssection model and considering effects of wind flow velocity and wind flow temperature,is easy and convenient; it can meet the construction requirements. 2） The wind flow velocity in tunnel and wind flow field at tunnel portal have a significant influence on tunnel temperature field. The temperature of secondary lining surface increases by 7. 2 ℃ when wind flow temperature at tunnel portal increases by 10 ℃. The temperature of secondary lining surface reduces by 6. 6℃,2. 7 ℃,1. 5 ℃ and 0. 9 ℃ when the wind flow velocity is 2 m / s,3 m / s,4 m / s and 5 m / s respectively.