水化热对高温多年冻土区桩基温度场的影响  

Influence of hydration heat on temperature distribution field along piles in warm permafrost regions

作　　者：李健宁[1] 孙学先[1] LI Jianning;SUN Xuexian(School of civil engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]兰州交通大学土木工程学院

出　　处：《铁道科学与工程学报》2019年第12期2984-2990,共7页Journal of Railway Science and Engineering

摘　　要：为研究混凝土水化热对高温多年冻土区桩基温度场的影响,以传热学为理论基础,给出温度场的控制微分方程和边界条件,采用有限元数值分析方法求解,分析混凝土灌注桩施工后桩土温度场的分布规律,讨论入模温度及混凝土水化热对回冻过程的影响。研究结果表明:入模温度和混凝土总水化热对回冻过程有显著影响,回冻时间随入模温度的增加而延长;随总水化热的降低而减少。对高温多年冻土而言,混凝土灌注桩施工带给冻土温度场的热扰动使回冻过程更为漫长,可通过在混凝土中适当加入粉煤灰和矿渣等掺合料及降低混凝土入模温度来减少回冻时间,缩短施工工期。In order to study the influence of concrete hydration heat on temperature distribution field along pile foundation in warm permafrost regions, the control differential equations and boundary conditions of temperature field were given based on the heat transfer theory, the distribution of temperature field after concrete cast-in-place pile foundation construction was studied by finite element method, and the influence of molding temperature and total concrete hydration heat on the process of refrozen was discussed. The results showed that the molding temperature and total hydration heat of concrete had a significant effect on the refrozen process. Refrozen time was prolonged with increasing the molding temperature, but decreased with the reduction of total hydration heat. For warm permafrost, thermal disturbance to temperature field of permafrost by the construction of concrete cast-in-place pile made the process of refrozen more long. In order to reduce the refrozen time and shorten construction duration, the mineral admixtures such as fly ash and slag powder could be added to the concrete, and the molding temperature of concrete could be reduced.

关 键 词：高温多年冻土 桩基础 混凝土水化热 温度场 

分 类 号：TU473[建筑科学—结构工程]