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分析了堆石料在等幅与不等幅应力循环荷载作用下的变形特性,以此为基础,确定了不同加载过程中堆石料的剪胀方程、加载方向、切线模量及塑性模量,建立了一个可以考虑堆石料循环加载特性的广义塑性本构模型。模型将所有的加卸载阶段都视为弹塑性过程,并在剪胀方程中引入老化函数来考虑体积应变积累对剪胀(缩)性的影响。模型共有12个参数,均可通过常规室内单调及循环加载试验确定。为验证模型的有效性,依据试验资料确定了两种不同堆石料的本构模型参数,并对等幅循环三轴压缩与不等幅循环三轴压缩试验进行了模拟。两种材料在不同围压下的模型预测结果与试验数据均吻合良好,表明模型可以有效地反映循环荷载作用下堆石料应力应变曲线的滞回特性与永久变形的积累。
Based on the analysis of the deformation characteristics of rockfill under cyclic loading with constant amplitude and unequal amplitude, the dilatancy equation, loading direction, tangent modulus and plastic modulus of rockfill in different loading processes are established and established A generalized plastic constitutive model can be used to consider the cyclic loading behavior of rockfill materials. The model considers all loading and unloading stages as elastoplastic processes and introduces the aging function into the dilatancy equation to account for the effect of volumetric strain accumulation on dilatancy. The model has a total of 12 parameters, which can be determined by conventional indoor monotonic and cyclic loading tests. In order to verify the validity of the model, the constitutive model parameters of two different rockfill materials were determined according to the test data, and the triaxial compression tests with equal amplitude cycle triaxial compression and unequal amplitude cycle were simulated. The prediction results of the two materials under different confining pressures are in good agreement with the experimental data, which shows that the model can effectively reflect the hysteretic behavior and permanent deformation of the stress-strain curve of rockfill under cyclic loading.