水化热对冻土地区桩基热影响分析

Effects of cement hydration heat on pile foundation in permafrost regions

针对冻土区灌注桩基础施工会给冻土引进一定的热量,破坏冻土的稳定冻结状态问题,研究水化热对桩基沿径向温度变化规律及影响桩周冻土温度场的时间。基于桩和冻土的三维非稳态温度场控制方程,并考虑边界条件和冻融相变过程,建立了桩基非稳态温度场控制方程。对桩周温度场的热影响分析表明,浇筑混凝土后水化热在第5 d达到最大,水化热对桩长范围内桩侧土体径向温度变化的影响程度大于桩底面以下土体径向受水化热影响程度,水化热对桩周围土体有较大的影响而且时间长。得出的一些结论可为冻土区桩基设计施工提供参考。

Based on the heat of pored pile construction effect on the frozen foundation in permafrost regions,the paper studied the variation laws of radial temperature field and the influence time of thermal field of pile foundation caused by cement hydration heat.Based on nonlinear transient temperature field equations for piles and forzen soil,considering boundary conditions and freeze-thaw process of transformation,transient temperature field equations for pile foundation in cold region is established.The results show that the 5th days occur the maximum hydration heat after the pouring of concrete and the hydration heat affect on the radial temperature of soil along pile length is greater than under pile bottom and the hydration heat has significant thermal perturbation and a long time effect on the thermal stability of pile foundation.The conclusions can provide a reference for the design and construction in permafrost region.