Methodology for Simulation of Irregularly Shaped Gravel Grains and Its Application to DEM Modeling

Abstract

The mechanical behaviors of gravelly sands are greatly affected by the morphology and size of gravel grains. In this paper, a systematic approach that integrated computational geometry was proposed to simulate gravel grains with different angularity and aspect ratio in discrete element method (DEM) modeling. A random circumscribed polygon was first created, and disks of different sizes were laid along medial axes of the polygon. This medial-axis-oriented disk-laying approach was very efficient with regard to the high area coverage rate achieved and the number of disks employed for one gravel grain. As to the size of simulated gravels, the Weibull distribution was used to generate size distribution curves close to natural grains. The proposed approach was able to produce gravel grains of random shapes with reasonable grain sizes. Finally, a series of biaxial tests were conducted on the numerically generated gravelly sand specimens to investigate the influence of gravel content and gravel morphology on specimen strength at macroscopic and microscopic scales.