For land creation regarding coastal structures, large mounds of soil, sand, and blocks are emplaced for mound formation, while accurate prediction of sedimentation deposition steps is necessary for cost reduction of construction work. In this study, high-resolution calculations using computational grids as fine as one to several tens with regard to typical block size are performed to ascertain details of flow fields around the blocks. The Smagorinsky model is introduced to investigate a turbulence field under high particle Reynolds number conditions. The deposition steps of block groups thrown into the water and the flow fields surrounding blocks that are difficult for measurements are presented in detail. Complex turbulent flow is formed in the sedimentation process and the influence of turbulence is not negligible.