考虑颗粒破碎引起级配演变的粗粒料屈服函数研究

级配作为粗粒料的重要物理特性，显著影响着粗粒料本身的力学性质。准确预测土体在加载过程中的级配演变，是有效分析土体结构全寿命周期强度和变形特性的基础。引入Einav的分形破碎理论，认为土体在加载过程中的颗粒破碎耗能增量正比于颗粒分形破碎率增量，结合考虑颗粒破碎的能量平衡方程，选取已有文献中的试验数据，对粗粒料加载过程中的级配演变进行了研究，提出了一种预测试样加载过程中级配演变的方法。在此基础上，建立了一个可以反映粗粒料级配演变的屈服函数，对该屈服面函数进行了初步探讨。每一个屈服面对应土体的一个级配演化曲线；屈服面是土体剪切应变的等值面，屈服面的轨迹和剪应变大小密切相关。

Yielding function for coarse aggregates considering gradation evolution induced by particle breakage

Gradation, one of the most important physical characters of soils, has significant influence on the stress strain response of coarse aggregate. Accurate prediction of the gradation evolution during loading procedure is an essential part for efficient analysis of strength and deformation characteristics of soil structures. Following Einav’s fractal breakage theory, the energy dissipated from particle breakage during loading is assumed to be in direct proportion to the increment of fractal breakage ratio. Method of measuring the gradation evolution during loading as well as a novel yielding model considering gradation evolution of coarse aggregate is then established by employing a well-known energy equation. Investigation of the gradation evolution of coarse aggregates is thus conducted by employing corresponding experimental data from relevant literatures. After that, preliminary discussion of the newly proposed yielding function is also conducted. It is observed that each yield surface during loading corresponds to a specific gradation of coarse aggregate. Moreover, the yield surface is suggested to be a shear strain-based isosurface, of which the shape is mostly determined by shear strain.