Crushing characteristics of single particles are the basis of granular material simulation with discrete element method (DEM). To improve the universality and precision of crushable DEM model, inhomogeneous stiffness and strength properties are introduced into the bonded particle method, with which the Weibull distribution and size effect of particle strength can be reproduced without deleting elementary balls. The issues of particle strength and carrying capacity under complex contact conditions are investigated in this work by symmetric loading tests, asymmetric loading tests, and ball–ball loading tests. Results of numerical experiments indicate that particle carrying capacity is significantly influenced by coordination numbers, the symmetry of contact points, as well as the relative size of its neighbors. Contact conditions also show impact on single-particle crushing categories and the origin position of inner particle cracks. The existing stress indexes and assumptions of particle crushing criterion are proved to be inappropriate for general loading cases. Both the inherent inhomogeneity and contact conditions of particles should be taken into consideration in the simulation of granular materials.

单个颗粒的破碎特性是离散元法（DEM）模拟颗粒材料的基础。为提高可压碎DEM模型的通用性和精度，在结合粒子法中引入非均匀刚度和强度特性，在不删除基本球的情况下再现粒子强度的威布尔分布和尺寸效应。在这项工作中，通过对称加载测试、非对称加载测试和球-球加载测试，研究了复杂接触条件下的颗粒强度和承载能力问题。数值实验结果表明，配位数、接触点的对称性以及相邻点的相对大小对粒子的承载能力有显着影响。接触条件也显示出对单颗粒破碎类别和内部颗粒裂纹起源位置的影响。现有的应力指标和颗粒破碎准则的假设被证明不适用于一般加载情况。在模拟颗粒材料时，应同时考虑颗粒固有的不均匀性和接触条件。