承台大体积混凝土温度效应研究

摘要：随着我国交通事业的高速发展，大跨度混凝土桥梁大量修建，在桥梁施工过程中变暴露出了许多问题，其中温度应力引起的温度裂缝问题尤为突出，因此，大跨度预应力混凝土桥梁的温度场分布及其引起的温度效应被广大桥梁研究工作者的重视。本文以九江长江大桥为工程背景，具体分析南塔承台温度场的分布特点，将计算结果与工程实测值进行分析对比，总结出承台温度控制的具体措施。

关键词：斜拉桥承台温度效应仿真计算

Abstract: With the rapid development of our transportation, large number of Long-span concrete bridges have been built, many problems occurred in procedure of bridge construction, The temperature rift problem caused by temperature stress is more especially pronounced, therefore the problem of long-span concrete bridge in temperature field peculiarity and the temperature effect caused by them should be paid attention to by bridge researchers, taking Jiujiang Yangtze River bridge as the engineering background, this paper analysis the temperature field and temperature stress characteristic of South Pylon pile cap. then the theoretical result will be compared with experimental results and analysis will be made to the temperature controls of the bridge pile cap in the current project.

Key words: cable-stayedbridge pile captemperature effectsimulation

中图分类号 :TV544+.91文献标识码： A 文章编号：

工程概况

九江长江大桥南塔承台采用两个边长为22.5m×22.5m×8m分离式承台。每个承台下设14根直径2.8m，长80.4m桩基。单个承台工程数量分别为： HRB335级钢筋302008.4Kg ，混凝土方量3555.09m3，属典型大体积混凝土承台。承台施工采用钻孔桩加摆喷桩围护结构进行支护，基坑开挖后，分两次进行浇筑混凝土，每次浇筑高度为4m。图1为主墩承台结构图。

图1 主墩承台结构图

承台混凝土施工按大体积混凝土温控方案进行控制施工，该承台施工的难点有：（1）冬季施工，外界气温较低，混凝土表层散热较快，内外温差难以控制。（2）混凝土体积较大，内层混凝土降温缓慢，混凝土水化热较高。(3)由于