Reproduction of Discrete Element Model by 3D Printing and Its Experimental Validation on Permeability Issue

The results of laboratory tests for examining the mechanical properties of a geomaterial always vary because of the changes in the microscopic structure. Same results for the tests cannot be obtained even on using the same particle aggregation owing to the influence of particle arrangement. In this study, we attempt to replicate the particle arrangement using 3D printing and examine the feasibility of evaluation of this influence experimentally. A 3D printed specimen is made from numerically simulated packing samples using discrete element method (DEM). This printed specimen shows good reproducibility as verified from the comparison of the cross-section of the specimen obtained using X-ray CT scanning. To validate the mechanical parameters, the value of the permeability coefficient of the 3D printed specimen obtained from laboratory testing is compared with that obtained from numerical simulations using DEM coupled with simplified maker and cell method and permeability-estimating equation. The permeability coefficients obtained using each method are found to be qualitatively consistent. Conclusively, we demonstrate the reproducibility of numerical simulation through experimental validation focusing on permeability.