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粗粒料在外力作用下存在明显的颗粒破碎特性,研究颗粒破碎过程是当前研究的热点问题之一。基于粗粒料单颗粒破碎机制,考虑单颗粒破碎强度与直径的变化规律,采用非线性接触H-Z模型和密度控制法建立了粗粒料颗粒破碎数值模型。开展粗粒料双轴剪切试验数值模拟研究,并与室内试验结果进行对比分析。研究表明:建立的粗粒料颗粒破碎数值模型能够较好地模拟粗粒料偏应力与轴向应变和体积应变与轴向应变的关系;数值模拟获得的粗粒料颗粒破碎率与室内试验结果基本一致;去除试样制备过程和固结过程引起的颗粒破碎,不同围压条件下的颗粒破碎率归一化后基本重合,且可以近似地采用双曲线函数进行拟合。颗粒破碎率随着围压的增大,逐渐增大,试验级配趋于Einav提出的颗粒破碎的最终级配(分维数等于2.6)
Under the action of external force, coarse aggregate has obvious characteristics of particle crushing. Studying the process of particle crushing is one of the hot issues in current research. Based on the single-particle crushing mechanism of coarse aggregate and considering the variation of single-particle crushing strength and diameter, a numerical model of particle crushing of coarse aggregate was established by nonlinear contact H-Z model and density control method. The numerical simulation of biaxial shearing test of coarse aggregate was carried out and compared with the indoor test results. The results show that the established numerical model of coarse aggregate particle crushing can well simulate the relationship between the deviatoric stress, axial strain, volumetric strain and axial strain of coarse aggregate; The particle crushing caused by the process of sample preparation and consolidation was removed. The particle crushing rates under different confining pressure were normalized and basically coincided, and the hyperbolic function could be fitted approximately. The particle crushing rate increases with the increase of confining pressure, and the experimental gradation tends to the final gradation of particle crushing proposed by Einav (the fractal dimension is equal to 2.6)