【摘要】 考虑大气温度、水文地质条件,混凝土入模温度、冻土初始地温场的影响及相变效应,以传热学为基础,给出了冻土区单桩地温场控制微分方程、边界和初始条件,以及其空间分析的有限元计算模式。结合工程实例对青藏高原典型湿润性地段多年冻土区的钻孔灌注桩单桩回冻过程温度场进行了计算,给出了桩身温度随深度及回冻时间的变化。以设计规范为基础对单桩回冻过程中温度场的变化对单桩承载力的影响及施工进程的影响进行了分析,所得结论可为多年冻土区桥梁工程施工计划的制定提供理论依据。更多还原

【Abstract】 Based on the theory of heat conduction,this paper presents governing differential equations of ground temperature field,boundary conditions,initial conditions and finite element model for single pile in permafrost with the consideration of air temperature,hydrogeological conditions,concrete temperature,initial ground temperature field,and phase-change effect. For a cast-in-place bored pile in a practical bridge structure that was built in the representative humid permafrost in the Qinghai—Tibet plateau,the ground temperature field of refreezing process was calculated. The temperatures along the pile body varied with the depth and refreezing time, which were used to evaluate the variation of bearing capacity of the single pile and influence of temperatures on the plan of bridge construction according to the bridge code. The presented procedure and conclusions achieved can provide a theoretical basis for shortening construction period and laying out bridge construction plan in permafrost regions.更多还原