循环荷载作用下砂土液化特性的非圆颗粒数值模拟

针对纯圆颗粒模拟的缺陷,利用颗粒流计算程序的团颗粒方法开发了形状近似实际角粒砂的角粒团颗粒,研究了颗粒形状变化对数值试样液化特性的影响及其细观机理。利用自行开发的随机数制样方法制备出多种形状颗粒随机混合的仿真试样,分析了振动液化过程中细观组构的演化规律,并与砂土可视化模型试验结果进行了对比。结果表明,颗粒棱角度越大,试样抗液化能力越强,其在细观机理上与初始平均接触数大小有关;随机混合仿真试样可以从定性角度反映实际砂土振动液化过程中的细观组构演化规律,为今后进一步的定量研究奠定了基础。

Numerical simulation of liquefaction of sands with non circular particles under cyclic loading

The clump logic of particle flow code PFC2D/3D is utilized to develop angular particle element for simulation of sand.The influence of particle shape on sand liquefaction behavior is numerically studied and the related mechanism is explained from microscopic view point.The regularity of fabric evolution during liquefaction under cyclic loading is analyzed by using emulative samples randomly mixed from particles with multiple shapes and compared with the visualized experimental results.The results of numerical simulation reveal that the resistance to liquefaction of sands increases as the angularity of particles increased,and the micro-mechanism is related to the average coordination number of sample.It also found that the numerical sand sample made from randomly mixing multiple shapes of sand can quantitatively reflect the regularity of fabric evolution of sands during liquefaction.