The behavior of granular materials subjected to shear loading is often very complex to be correctly characterized. Loads on a discrete medium composed by several grains lead to a diffusion of stresses in the medium by contact and frictions between individual grains. This stress diffusion combined to inter-granular relative movements induces some cracking in the contact zones and even some complete grain crushing. This results in producing other grains of smaller size, changing thus the grain size distribution of the original material and its mechanical behavior law. Quantifying the rate of crushing is of significant importance for understanding the behavior of the granular medium. In the present work, a statistical study of crushing grains in a granular medium subjected to shear load is presented. A probabilistic model using the Weibull distribution is proposed to evaluate the rate of crushed grains as a function of the applied load. The material used in this study are limestone graine of diferent size, produced from crushing of healthy rock. The obtained results showed that the breakage of grains under shear load depends mainly on their dimensions and on the intensity of the applied load. Also, statistical modeling using the Weibull method produced satisfactory adjustment of the experimental data.

粒状材料承受剪切载荷的行为通常非常复杂，无法正确表征。由多个晶粒组成的离散介质上的负载会由于各个晶粒之间的接触和摩擦而导致应力在介质中扩散。这种应力扩散与晶粒间的相对运动相结合，在接触区域引起了一些开裂，甚至导致了完全的晶粒破碎。这导致产生其他较小尺寸的晶粒，从而改变了原始材料的晶粒尺寸分布及其机械行为规律。量化破碎速率对于理解粒状介质的行为非常重要。在目前的工作中，统计研究了颗粒状介质在剪切载荷作用下破碎颗粒的情况。提出了使用威布尔分布的概率模型来评估压碎谷物的速率与所施加载荷的函数关系。本研究中使用的材料是不同大小的石灰石颗粒，它们是通过将健康岩石压碎制成的。所得结果表明，在剪切载荷作用下晶粒的破裂主要取决于晶粒的尺寸和所施加载荷的强度。同样，使用威布尔法的统计模型对实验数据进行了令人满意的调整。