基于PFC2D的岩土体孔隙统计算法分析

为了研究岩土材料微观孔隙结构特性,从机理上认识和掌握其宏观工程性质及其变化规律,基于PFC2D模拟岩土材料孔隙结构,对像素颗粒填充法的计算误差、像素颗粒尺寸选择及孔隙统计算法等进行了研究。研究结果表明:综合考虑误差控制与计算效率,建议最小土石颗粒半径的1/20为适合的像素颗粒半径;对比孔隙体积统计的3种算法发现,舍入法是相对最优算法。在此基础上实现了等效孔径分布的统计,为三维孔隙结构模型的研究提供了理论依据,为进一步对岩土材料孔隙结构特性及其与宏观力学行为和工程性质间关系的研究提供了基础。

Statistical Algorithms for Pore Size Distribution of Rock-soil Mass Based on PFC2D

The purpose of this research is to obtain the microscopic structural characteristics and the variation rules of macroscopic engineering properties of rock and soil materials.We discussed the issues of statistical error,pixel size,and statistical algorithms for pixel-particle-filling method by simulating pore structures in rock and soil samples using PFC2D (2-dimensional particle flow code).Results show that taking into account both statistical error and algorithmic efficiency,we recommend 1/20 of the radius of the smallest particle as the proper radius for pixel-particle-filling used for pore structure statistics.We also compared three pore volume statistical algorithms and found that round-off method is the optimal.Moreover,we proposed a method to obtain the curve of equivalent pore size distribution,based on which further research works are able to be conducted on the 3D pore structures model,the characteristics of the pore structures and the relationship among these characteristics and macro-mechanical behaviors and engineering properties of rock-soil.