摘要
桩的残余应变对桩的轴力分布曲线有显著影响,目前对灌注桩残余应变的研究还很少。该文首先通过构建灌注桩加载前应变状态的多场耦合模型,在模型中,叠加了桩身自重、混凝土收缩、温度变化和蠕变产生的应变,得到了残余应变的理论结果,其与具体工程的长期监测结果吻合较好;接着对理论结果与实际结果的差异进行了分析,认为产生差异的主要影响因素是养护过程中桩周实际边界条件的复杂性和无法直接测量混凝土参数(弹性模量,热膨胀系数),这些因素限制了表达式的应用范围;最后对公式中弹性模量进行了修正,使其结果与实际结果吻合更好。该文初步揭示了灌注桩残余应变产生的机理,并能解释KisterG(2007)的监测结果。桩身的残余应变对桩身的质量,桩端和桩身受力以及桩侧与岩石接触状况都有影响,在工程实践中值得关注。
The residual strain in a pile markedly influences the axial force distributing curve of a pile, but it was rarely studied on cast-in-place piles. The strain state of a Multi-field coupling model for a pile before loading is first constructed. In the model, according to adding up the strain respectively produced by self-weight of a pile, concrete shrinkage, change of concrete temperature and creep, theory expressions for residual strain is derived, and its results fit close to monitoring results in construction practice. In succession, the differences between theory results and monitoring results are analyzed; the main influence factors for the differences are complicated boundary condition around piles and difficulties on measuring parameters of concrete in curing, and those factors limited application area of the theory expressions. Lastly, according to revising elastic modulus, the theory reaults fit closer to the monitoring results. In general, generate mechanism of residual strain in east-in-place piles are elementarily explained, and it can also explain results of Kister G （2007）. The residual strain of a cast-in-place pile has influence on the pile quality, bearing behavior on the pile body and bottom, and contact status between the pile side and rock around the pile, so it deserve to be noticed in construction practice.
出处
《工程力学》
EI
CSCD
北大核心
2009年第7期125-133,共9页
Engineering Mechanics
基金
湖南省科技厅重点项目(04SK2008)
湘潭大学科研启动项目(KZ08007)
关键词
残余应变
灌注桩
混凝土自收缩桩的自重
温度场
residual strain
cast-in-place pile
autogenous shrinkage of concrete
self-weight of pile
temperature field
