寒区隧道不同类型冻土段隔热(保温)层铺设厚度计算方法

Piecewise Calculation Method for Insulation Layer Thickness in Cold Region Tunnels

为了给寒区隧道工程中隔热(保温)层的设计提供参考,采用理论分析、温度场数值模拟计算等手段,对不同类型冻土段隔热(保温)层厚度的初步计算方法进行研究。结果表明:洞口浅埋季节活动层段的保温层无法阻止围岩的冻融循环,在进行保温层设计计算时可不予考虑;多年冻土段隔热层厚度的计算应综合考虑围岩的初始地温、施工期间二衬混凝土水化热以及施工期间的洞内气温等因素,以保证计算结果的合理性;洞口年平均气温大于0℃和小于0℃两种情况下,非冻土段保温层厚度的计算方法也不同,应根据工程实际情况选择相应的计算方法。

In order to provide reference for design of insulation layer in cold region tunnels, theoretical analysis and finite element analysis were used to deduce piecewise calculation method of insulation layer thickness in cold region tunnels. The results show that to the seasonally frozen ground through which tunnel passes, it＇s useless to lay insulation layer to protect surrounding rock from being frozen and the calculation of insulation layer thickness should not be taken into account; in the solution process of insulation layer thickness in permafrost, initial temperature, hydration heat of the cast-in-place concrete lining and the high temperature in the tunnel during construction should be considered; in non-frozen ground, the calculation method of insulation layer thickness, when the annual average temperature outside the tunnel is higher than 0 ℃, is different from the case in which the annual average temperature outside the tunnel is below 0 ℃. The calculation method should be chosen according to the actual situation of the tunnel.