中文摘要：

针对多年冻土地区灌注桩施工桩周温度场的热影响问题,研究水化热对桩基沿径向温度变化规律及影响半径问题。基于非稳态温度场控制方程,分别建立了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,最终建立了桩基非稳态温度场的有限元计算模型。运用该模型对实际工程中灌注桩基产生的水化热对桩周温度场的热影响问题进行分析,得出浇筑混凝土后,不同深度处随龄期增加沿径向桩基温度变化规律及水化热引起较大热扰动半径约为6倍桩径,水化热对桩周围土体有较大的影响而且时间长,应采取措施减小混凝土水化热,从而达到减小冻土区桩基热影响问题。

英文摘要：

Based on analyzing the thermal effects of pile construction on pile foundation in permafrost regions, the variation laws of radial temperature field and the thermal perturbation radius of pile foundation caused by cement hydration heat are studeied. In view of the transient temperature field equations, nonlinear transient temperature field equations for piles and forzen soil are respectively fomulated. Considering the boundary conditions and freeze-thaw process of transformation, a finite element model of transient temperature field for pile foundation in cold regions is established. The model is employed to simulate the thermal perturbation of pile foundation caused by cement hydration heat. The variation laws of radial temperature field with time at different depths and thermal perturbation regions about 6 times the radius of pile diameter are acquired. The results show that the hydration heat has significant thermal perturbation and long-term effects on the thermal stability of pile foundation. In order to reduce the perturbation, it is essensial to reduce the hydration heat of concrete in permafrost regions.