压弯作用下混凝土支撑体系受温度变化对支撑轴力的影响分析

Influence Analysis of Temperature Change on the Axial Force of Concrete Support System under the Compression&Bending Action

随着我国城市化进程的推进,城市基建工程建设速度迅速加快。大量基坑工程中的支撑体系对基坑工程安全起到至关重要的作用。在压弯作用下,必须研究温度变化对基坑支撑结构内力的影响。基于文克尔地基梁计算模型,采用弹性抗力法,对已有的温度升高引起支撑轴力变化的简化公式进行改进,得到经验公式值;采用有限元数值模拟方法,研究压弯荷载(含支撑自重)和温度变化共同作用下混凝土支撑结构的内力,得到数值解;最后,将经验公式值、数值解分别与实测值进行对比分析。结果表明:数值解大于经验公式值,且实测值小于经验公式值,但差值不大可作为设计安全储备。该结论有望对实际基坑工程设计提供参考。

With the advancement of urbanization in China,the construction of urban infrastructure projects is accelerating rapidly,among which the foundation pit project is the cornerstone of urban infrastructure construction.At the same time,the foundation pit support system plays an important role in ensuring the safety of foundation pit engineering.This paper mainly studies the influence of temperature change on the internal force of foundation pit support structure under the action of compression and bending.Based on Winkler Foundation Beam Model,the elastic resistance method is adopted to improve the existing simplified formula of support axial force caused by temperature rise,and the theoretical value was obtained.By means of finite element numerical simulation,the internal force of concrete supported structure under the action of bending load(including supporting dead weight)and temperature change is studied,and the numerical solution is obtained.Finally,the theoretical and numerical values are compared with the measured values.The results show that the numerical solution is larger than the theoretical value,and the theoretical value is larger than the measured value,the results are conservative,but the difference is not large enough to be used as design safety reserve,the conclusion is expected to provide reference for the actual foundation pit engineering design.