单轴、双轴和三轴徐变试验结果表明,混凝土的徐变与弹性变形一样具有空间特性,但根据单轴徐变试验得到的徐变系数、徐变泊松比以及采用叠加原理计算的双轴、三轴应力状态下的空间徐变与实际情况存在较大偏差.为了准确计算不同应力状态下混凝土的空间徐变,介绍了应力组合对有效徐变泊松比的影响和基于有效徐变泊松比的空间徐变计算方法.另外,根据应力张量的弹性力学意义,引入了球应力徐变系数(ψ)m和偏应力徐变系数(ψ) d,提出了基于这两个徐变系数的空间徐变计算统一表达式,可计算混凝土在单轴、双轴和三轴等不同应力状态下的空间徐变.%The results of uniaxial, biaxial and triaxial creep test show that, the creep of concrete holds spatial characteristics like elastic deformation. And the space creep results under biaxial and triaxial stress state, which are calculated by principle of superposition with creep coefficient and creep Poisson ratio based on uniaxial creep test, have obvious deviation to the fact. In order to calculate accurately the space creep of concrete under different stress state, the effect of stress state on effective creep Poisson ratio and the method to calculate space creep based on effective creep Poisson ratio are introduced. In addition, the spherical stress creep coefficient ψm and deviatoric stress creep coefficient ψd are presented, and the uniform formulation based on the two creep coefficient is put forward, which can calculate the space creep of concrete under different stress state of uniaxial, biaxial and triaxial.
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