以三维离散元颗粒流理论为基础，PFC3D_EV为工具，改进内置程序代码，对比粗粒料室内三轴固结排水试验结果，生成颗粒接触点数均匀、各向同性应力相同的三轴试验数值模型。引入clump颗粒提高了数值试样内部颗粒形状的复杂度，对比了不同围压下数值试验应力—应变曲线、变形曲线与室内试验的差异，并探讨了剪切带发展规律及颗粒形状对粗粒料强度、变形特性的影响。结果表明：颗粒形状是影响粗粒料工程力学特性的主要因素，提高试样内部颗粒形状的复杂性可获得与物理试验拟合较好的应力—应变曲线；数值模型暂无法实现颗粒破碎状态，造成大应变时剪胀偏大；位移场发展变化过程显示应变软化加速了剪切带的形成；高围压下剪切带明显，且围压越高厚度越薄。

Based on the results of laboratory triaxial consolidated-drained tests on coarse grained materials and three-dimensional discrete particle flow theory, a numerical model of triaxial test for coarse grained materials with uniform particle contact points and same isotropic stresses was developed using the tool of PFC3D_EV and improvement of program code. Clump particles were introduced to improve the complexity of internal particle shape of the sample. The differences of stress-strain curves and volumetric strain - axial strain curves of triaxial tests under different confining pressures were compared, and the impacts of particle shape and the development law of shear bands on the strength and deformation characteristics of coarse grained materials were discussed. The results showed that (1) particle shape is the main factor on the mechanical behavior of coarse grained materials. The stress-strain curve obtained from the numerical simulation matches well with the experimental results if the complexity of internal particle shape is improved; (2) the shear dilatancy of numerical simulation is a little larger because the particle deformation and breakage cannot be performed in numerical simulation; (3) the development of displacement field indicates that strain softening accelerates the formation of shear bands; and (4) the thickness of shear bands becomes thinner with the decreasing of confining pressure .

新疆维吾尔自治区自然科学基金面上项目（2013211A027）