In this paper, it is proposed a new type of water-sediment separation device named sediment concentrated spiral tube (SCST), which is used in hydraulic fill. To confirm layout form of clear liquid discharge port—key components of the device, several tentative of clear liquid discharge port of SCST were investigated by numerical simulation and physical experiment. Considering the engineering applicability and efficiency of concentration, this paper selected the outside discharge port, whose discharge pipe was perpendicular to the main pipe, as the recommended clear liquid discharge port for SCST. Overall, the results showed: SCST, with the selected layout form, not only could improve sediment concentration for hydraulic fill, but also reduced the content of fine particles, as well as improved the engineering properties of fill sediment.