A DEM investigation of the effect of particle-size distribution on one-dimensional compression
A DEM investigation of the effect of particle-size distribution on one-dimensional compression
复制标题
DOI：
10.1680/geot.10.p.058
复制
发表时间：
2013-01-01
期刊：
影响因子：
5.8
通讯作者：
Cheng, Y. P.
中科院分区：
文献类型：
--
作者：
Minh, N. H.;Cheng, Y. P.
采用离散元法（DEM）研究了颗粒粒径分布对颗粒土材料一维压缩特性的影响，并将结果与已发表的具有相似等级的实验数据进行了比较。在这项研究中使用的颗粒是球形的，它们的大小范围模拟了各种幂律分布。对接触公式进行了校准，使得不同的非均匀组件的可压缩性和初始比容完全取决于不同粒径的非均匀级配的相互作用。这些组合物的压缩行为可分为大颗粒主导或小颗粒主导。提出了颗粒尺寸分布对填料特性和可压缩性影响的微观力学解释。参与强作用力传递的颗粒，携带比平均接触力大，被发现有助于颗粒样品的刚度。当具有相同分级的松散和致密样品被压缩到其刚度相同的阶段时，发现这些颗粒在强力网络中具有相同的尺寸分布。对于某些材料，存在不携带任何强作用力的颗粒区域，这些小颗粒部分填充大颗粒之间空隙的非仿射运动尤为显著。这种行为在DEM模拟中是可视化的。当这些粒子重新排列自己时，这些区域有助于更高的体积压缩。DEM颗粒的配位数随着分级的提高而显著增加。因此，通过颗粒破碎来改变真砂的粒度分布会导致颗粒配位数的增加，并且在压缩后期会逐渐降低颗粒破碎的概率，这在其他实验室实验中也有观察到。
The effect of particle-size distribution on the one-dimensional compressive behaviour of granular soil materials was investigated using the discrete-element method (DEM), and the results were compared with published experimental data with similar gradations. The particles used in this study were spherical, and their size range mimicked various power-law distributions. The contact formulation was calibrated such that the different compressibility and initial specific volume of non-uniform assemblies depended purely on the interaction of different particle sizes of the non-uniform gradations. The compressive behaviour of these assemblies can be classified as either big-particle-dominated or small-particle-dominated. The underlying micromechanical explanations for the effect of the particle-size distribution on the packing characteristics and on the compressibility are presented. Particles involved in the strong force transmission, which carried larger-than-average contact forces, were found to contribute to the stiffness of granular samples. When loose and dense samples with the same grading were compressed to a stage where their stiffnesses were identical, an identical size distribution was found for those particles involved in the strong force network. For some materials, there existed regions of particles that did not carry any strong force, and the non-affine movements of these small particles partially filling the void space between the bigger particles were especially significant. This behaviour was visualised in the DEM simulations. As these particles rearranged themselves, these regions contributed to a higher volumetric compression. It was also found that the coordination number of DEM particles significantly increased with better gradations. A change in the particle-size distribution of real sand through particle breakage would therefore lead to a higher coordination number of particles, and it would gradually reduce the probability of particle breakage during the later stages of the compression, as has been observed in other laboratory experiments.