中文摘要：

对排土场粗粒土进行室内三轴固结排水试验，以此试验结果为基础，基于三维离散元颗粒流理论，从细观角度出发，以PFC如为工具，通过自编程序并引入接触黏结模型，得到按级配生成的粗粒土三轴试验三维颗粒流模型。对比了不同围压下颗粒流模型与三轴试验的应力应变关系。分析了颗粒细观参数对粗粒土强度的影响。结果表明：按级配曲线得到的PFC数值模型的应力应变曲线的变化趋势与试验值一致，但强度值略低于试验值。粗粒土强度随颗粒间摩擦系数、接触处黏结强度的增大而提高；颗粒形状对材料的抗剪强度影响显著。研究意义在于从细观角度揭示影响粗粒土强度的因素，突破了常规三轴试验的局限性。

英文摘要：

Consolidated-drained triaxial test is conducted for coarse-grained soil, based on the values of this test and three dimension particle flow code theory, the numerical model of triaxial test for graded coarse-grained soil is obtained by programming PFC3D （particle flow code of three dimension）from the view of microscopic scale. Stress-strain relationship of particle flow model and triaxial test are compared under different confining pressure. The influence of micro-properties on coarse-grained soil strength is analysed. The numerical results show that the strength of PFC model is lower than that of test, the increasing of friction coefficient between particles and bonded strength in contact result in higher strength of model. The particle shape has significant effects on the shear strengfh of numerical model, The research found the effect on coarse-grained soil Strength from the view of＇ microscopic scale and the results overcome the limits of real lab tests.