Abstract The coarse granular materials in the pavement base and subbase layers are generally in the stress state of three dimensional anisotropy, while most previous experimental researches regarding the base and subbase materials focused on the isotropic or axisymmetric K0 stress conditions. In this study, the resilient characteristics of unbound granular materials in initial three dimensional anisotropic stress states were investigated through an electro-mechanical true triaxial apparatus. The influences of initial shear stress, qini, coefficient of intermediate principal stress, b, amplitude of cyclic major principal stress, σ1ampl, and moisture content on the resilient responses of granular materials were investigated. Test results reveal that the resilient response of unbound granular materials is strongly affected by the three dimensional stress anisotropy in the saturated condition. With the increase of b from 0 to 0.8, a significant reduction of Mr occurs, and this reduction becomes intensified as qini increases. It is also found that Mr is increased by the increase of qini for almost all tests, and the increasing rate varies at different σ1ampl, b and moisture content values. Based on the experimental results, an empirical model to predict resilient modulus is proposed incorporating the effects of initial three dimensional stress anisotropy, which is expected to serve as a basic model to calculate the resilient modulus of granular materials in three dimensional stress state.

中文翻译：

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三维各向异性应力状态下粗粒料的回弹行为

摘要 路面基层和底基层中的粗颗粒材料一般处于三维各向异性的应力状态，而以往有关基层和底基层材料的试验研究大多集中在各向同性或轴对称K0应力条件下。在这项研究中，通过机电真三轴装置研究了未结合颗粒材料在初始三维各向异性应力状态下的弹性特性。研究了初始剪应力qini、中主应力系数b、循环主应力幅值σ1ampl和含水量对颗粒材料回弹响应的影响。试验结果表明，在饱和状态下，未结合颗粒材料的弹性响应受三维应力各向异性的强烈影响。随着 b 从 0 增加到 0.8，Mr 出现显着减少，这种减少随着 qini 的增加而加剧。还发现对于几乎所有的测试，Mr 都随着 qini 的增加而增加，并且增加率在不同的 σ1ampl、b 和水分含量值下有所不同。根据实验结果，提出了一种结合初始三维应力各向异性影响的弹性模量预测模型，有望作为计算颗粒材料三维应力状态下弹性模量的基本模型。Mr 显着减少，这种减少随着 qini 的增加而加剧。还发现对于几乎所有的测试，Mr 都随着 qini 的增加而增加，并且增加率在不同的 σ1ampl、b 和水分含量值下有所不同。根据实验结果，提出了一种结合初始三维应力各向异性影响的弹性模量预测模型，有望作为计算颗粒材料三维应力状态下弹性模量的基本模型。Mr 显着减少，这种减少随着 qini 的增加而加剧。还发现对于几乎所有的测试，Mr 都随着 qini 的增加而增加，并且增加率在不同的 σ1ampl、b 和水分含量值下有所不同。根据实验结果，提出了一种结合初始三维应力各向异性影响的弹性模量预测模型，有望作为计算颗粒材料三维应力状态下弹性模量的基本模型。