The strength, deformation, and hydraulic properties of geomaterials, which constitute embankments, vary with fine fraction content. Therefore, numerous research studies have been conducted regarding the effects of fine fraction content on the engineering properties of geomaterials. Howe ver, there have only been a few studies in which the effects of fine fraction content on the soil skeletal structure have been quantitatively evaluated and related to compaction and mechanical properties. In this study, mechanical tests were conducted on geomaterials with various fine fraction contents to evaluate their compaction and mechanical properties focusing on the soil skeletal structure and void distribution. Furthermore, an internal structural analysis of specimens using X-ray computed tomography (CT) images was conducted to interpret the results of mechanical tests. As a result, it was discovered that the uniaxial compressive strength increased with fine fraction content, and the maximum uniaxial compressive strength was observed at a low water content, not at the optimum water content. Additionally, the obtained CT images revealed that large voids, which could ser ve as weak points for maintaining strength, decreased in volume, and small voids were evenly distributed within the specimens, resulting in a more stable soil skeletal structure.

Adding cement to soft soils may lead to brittle behavior and the occurrence of sudden damage. Methods to further improve the tensile and flexural properties of cemented clay are noteworthy topics. This paper mainly focuses on the effect of cement and moisture content on the strength and flexural properties of cemented clay reinforced by PVA fiber. The selected clayey soil was a kaolin with cement content of 5%, 10%, and 15% and moisture content of 50%, 56%, 63%, and 70%. The results show that the incorporation of 0.6% fiber can effectively improve the deformability of cemented clay in unconfined compression tests (UCS). The strengthening effect of fiber, as seen in the peak strength and post-peak strength of UCS, was significantly related to cement content. As the water content increased, the compressive strength of the fiber-reinforced cemented clay decreased, but its load-bearing capacity enhanced. When the cement content was 15%, the splitting tensile strength of fiber-reinforced cemented specimens increased by 11% compared to cemented soil, but the deformability of the specimens became poor. In the cement-content interval from 5% to 10%, the bending toughness was significantly improved. Sufficient cement addition ensures the enhancement of PVA fibers on strength and flexural properties of cement-stabilized clayey soil.