Effect of soil particle and pore orientations on sound velocity

The main purpose of compressing soil dams, highway constructions, bridge abutments and fillings behind retaining walls is to increase the bearing capacity, reduce consolidation settlement and permeability of clayey soils. However, the soil particles and pore orientation could be somehow anisotropic due to a compaction-induced anisotropic structure. Orientations of particles, pores and other constituents during compaction of a mixed mica schist clayey soil with fly ash were studied to investigate how soil structure, and in turn, sound velocity change during compaction of a cohesive soil at different moisture contents on all three sides at three are perpendicular to each other. Ultrasonic sound velocity measurements of the cube samples compressed in the optimum water content were investigated perpendicular to each other. The results showed that the ultrasonic sound velocity decreased in the compression direction of the soil samples, namely the overall degree of preferred orientation increases as opposed to the compression direction. On the other hand, the overall degree of preferred horizontal orientation increases and ultrasonic sound velocity decreases.