Study on the influence of coarse aggregate distribution uniformity on the compaction characteristics of gap-graded gravels

Abstract

There has yet to be a quantitatively characterised study that relates the degree of uniformity of aggregate distribution to the compaction of gap-graded gravels. The particle tracking technique was used to calibrate the vibrational compaction discrete element model, which was used to simulate the vibratory compaction of gap-graded aggregates at varying coarse aggregate contents (25 %, 50 %, and 75 %) and different coarse aggregate distribution uniformities ranging between 0.0 and 1.0. The results showed that with an increase in the coarse aggregate distribution uniformity, the amount of void ratio of gap-graded gravels under three coarse aggregate contents decreased significantly. The mechanism of variation in the effect of gap-graded aggregates with coarse aggregate distribution uniformity was found to be due to the variation of the local coarse content between layers: the disparity in the depth range of coordination number, stress transfer, distribution of strong and weak force chains and interlayer void ratio decreases with increasing coarse aggregate distribution uniformity. Hence, it improves the overall compaction effect and the homogeneity of the specimen. Local variations in coarse content between layers are considered to be the main cause of this effect.