Study on predicting the compacted density of rockfill materials based on the granular packing algorithm

The compacted density of rockfill materials is an important index to reflect their engineering and mechanical properties. A numerical granular packing algorithm, which is based on the dimension-reduction mapping and contains only one parameter, is proposed to determine the maximum density of rockfill materials in real time when the particle size distributions is given. Compared with the experimental results in the literature, the proposed algorithm can predict the maximum density of both well-graded and gap-graded rockfill materials, which provides a new idea for the effective optimization of the grading curve of rockfill materials. The effects of fines truncation and downscaling on the compacted density are analyzed using the proposed algorithm and it is found that: the proposed method can well predict the compacted density of the prototype rockfill materials based on the result of the down-scaled sample. The performance of the prediction of the scale effect is influence by the fines truncation, and the error of the predicted compacted densify is proportional to the fines content; From the point of view of granular packing, the skeleton voids of coarse content decreases for the downscaled specimens, disfavoring the filling of fines, while the increasing fines content with the downscaling procedure has no consistent effect on the compacted density of rockfill materials, and depends on both the particle size distributions of both the coarse and fine particles. © 2023 China Water Power Press. All rights reserved.