Hydraulic Gradient Reduction Effects on Sand-Water Mixture Flows Caused by Electro-Magnetic Force Generation

Abstract

Large coastal development projects are frequently accompanied by reclamation and dredging works to create coastal land. In coastal reclamation projects, the construction materials and their transportation methods should be determined from an economic perspective because they constitute a large portion of the construction cost. Therefore, improvements to transportation efficiency are strongly expected to contribute to a substantial reduction in construction costs. In this study, an electro-magnetic force (EMF) generation method is proposed, and the quantitative effects of this method are analyzed via hydraulic model experiments with variable practical conditions. The experimental results show that a change in the typical flow type from bottom rolling to suspension contributes to a significant reduction in the bottom resistance and hydraulic gradient because of the lowered deposition height after EMF generation. The EMF effect was larger in fine soils than in coarser soils, and EMF generation reduced the hydraulic gradient by approximately 10%. Thus, EMF generation technology can be applied to reduce transportation costs, including of dredged materials, in many types of fluid flowing projects.