混凝土水化热对寒区隧道围岩融化及回冻过程的影响

摘要

混凝土水化热是导致围岩融化的主要热量来源之一,不同水化热放热方程(不同放热速率)对结果影响较大.本文以昆仑山隧道为例,利用有限单元法计算考虑混凝土水化热及其放热过程和不考虑水化热的隧道围岩融化回冻过程,分析水化热对围岩融化、回冻过程的影响.2种工况计算中均考虑施工过程、隧道衬砌内缘温度变化、防水隔热保温层、入模温度、相变等因素.结果表明:在寒区隧道围岩施工过程中,混凝土水化热增加了围岩的最大融化深度,同时使围岩温度升高；考虑混凝土水化热影响寒区隧道围岩回冻时间比不考虑水化热情况晚1年.%Concrete hydration heat is one of the main sources of heat which causes surrounding rock to melt,different heat hydration and release equations (different heat release speeds) make a great impact on the melting results. Taking one Kunlun Mountain tunnel as an example, the surrounding rock melting and refreezing processes are simulated with the finite element method, and the influence of hydration heat on the surrounding rock melting and refreezing processes are analyzed under the conditions of considering and without considering the heat hydration and release processes. The construction process,temperature changes at the tunnel ling inner edge, waterproof and thermal insulation layer, concrete casting temperature and phase transition are taken into account in calculation under both operating conditions. The research results show as follows: In construction of tunnels in the permafrost region, the maximum thaw depth and temperature of surrounding rock are raised due to concrete hydration heat; the refreezing time of tunnel surrounding rock in the permafrost region is one year later considering the influence of concrete hydration heat when as compare with the situation, exclusive of the influence of concrete hydration heat.