Study of the change of width and depth of channel on sedimentation in box culvert by using SSIIM

Box culvert is a rectangular reinforced concrete closed channel that allows water to flow under a road, dam, railroad, and runway. Surabaya has constructed such a structure in several highways. The problem that often occurs in box culvert is the sedimentation. Sedimentation can lift up the change of the flow velocity and it can be influenced by the change in width and depth of the channel bed. This research simulated the change of width and depth of the channel bed of box culvert on the same location and the same length in certain distance. There were three variations of channel bed. The first was the initial dimension of the box culvert, the second is the change of channel bed into twice wider than the initial width, and the third was the change of channel bed into twice deeper than the initial depth. Those three variations were simulated by using the Simulation of Sedimentation Movement in Water Intakes with Multiblock Option Version 1 (SSIIM 1). The results of this simulation are the diagrams of velocity vectors, horizontal velocity, vertical velocity and sediment concentration in each variation. From the diagrams, the second and the third variation show that the location of sedimentation changes in line with the changes of width or depth of the channel bed.