Effect of particle size on the failure behavior of cemented coral sand under impact loading

The effect of particle size distribution (PSD) of coral sands on the failure behavior of cemented coral sand specimens is investigated in this study. A series of static and impact loading tests on the specimens with various grain grading curves have been carried out. Test results show that the compression strength and impact resistance of the cemented coral sand specimen are increased with the increasing of the uniformity coefficient of coral sand particles. The specimen with a higher value of the uniformity coefficient would have a smaller failure angle under the same impact loads. In addition, the micro mechanism of PSD on the macroscale mechanical behavior is explored by a three-dimensional discrete element model. Four typical realistic particles are scanned and incorporated in the numerical models. The numerical model is established with the same PSD and impact loading conditions. Calibration tests are carried out to verify the numerical model. Then, a series of numerical analysis are conducted to examine the effects of particle shape and PSDs on the failure behavior. Analysis results indicate that the contact force distribution and absorbed energy can be linearly influenced by the PSDs. The realistic particles with a lower shape factor will result in a higher impact resistance. Thus, an optimum PSD can be design to meet the requirement of impact loadings. The outcome of this study could benefit for the foundation design with the consideration of the impact loadings.