Abstract: 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.

Key words: pore structure, pixel-particle-filling method, PFC2D, equivalent pore size distribution curve, round-off method