球应力循环加载下粒状土变形规律与本构描述

Deformation characteristics and constitutive modeling of granular soils during cyclic loading with spherical stresses

为评价动力作用下饱和砂土的变形,通过试验,研究了球应力循环加载下饱和砂土的变形规律,提出描述各变形分量的本构模型。通过系列的饱和砂土球应力循环加载的动力三轴试验,分析体积应变和偏应变随循环次数的变化规律;从细观组构角度分析粒状土各变形分量的产生原因;给出弹性和塑性模量表达形式,描述各变形分量的发展规律。结果表明:不可逆性压缩体应变随循环次数不断累积,累积速率随累积量增加而降低;可逆性压缩体应变呈现可恢复的循环变化,可采用弹性方法描述;可逆性和不可逆性偏应变量相对较小,可以忽略。

The deformation characteristics of saturated sand during cyclic loading with spherical stresses was studied by experiments and modeled using a constitutive model.The volumetric and deviatoric strain characteristics were analyzed using test results during cyclic loading with spherical stresses on a triaxial device and the deformation mechanism of the strain components was described based on the micro fabric of the granular soils.Equations for the elastic and plastic moduli were developed to simulate the deformation components in the constitutive model.The results show that an irreversible compression volumetric strain accumulates with more cycles with the rate of increase decreasing with the number of cycles.The reversible compression volumetric strain cycles changes could be simulated with an elastic analysis.The reversible and irreversible deviatoric strains were relatively small and could be ignored.