Effect of Successive Impact Loading on Compactability, Microstructure, and Compressibility Behavior of Micaceous Sand

Abstract

Micaceous soils are generally known for their high compressibility, low compactability, and low shear strength behavior. Mica particles are flaky, flexible, and resilient nature with low stiffness and hardness due to numerous foliated intact mica flakes, which allows them to undergo deformation upon loading and rebound upon unloading. However, the weak mica particles among strong sand particles are highly susceptible to crushing, which affects the performance of geotechnical structures. The current research is focused on the effect of successive impact loading on crushability, compactability, compressibility, and microstructure of micaceous sand containing 30% mica. Significant increase in MDD, fine content, and compression index of micaceous sand was observed with the increase in successive cycles of impact loading. The reduction in resilient nature of micaceous soil due to crushing of intact mica particles along with the reduced bridging and ordering combination of sand-mica particles could be responsible for altered compactability behavior of micaceous sand. The increased percentage of fines due to crushing of mica particles caused the reduction in stiffness leading to higher compressibility of micaceous soil.