Effect of the Insertion Depth of the Shield on the Pipeline Scour at Different Distances of the Pipe from the Bed

With the advancement of science, human societies use transmission pipes to transport water and other fluids from the bed of seas, rivers, streams and natural drains. If pipelines pass through rivers and seabeds on their way, great care must be taken in their design. The main purpose of this study is to investigate the effect of the insertion depth of the shield on the pipeline scour at different distances of the pipe from the bed. This study was carried out in a flume with the length of 10 m and the width of 30 cm. Experiments were conducted under clear water condition (u/uc=0.95). Uniform sediment with a median diameter of one millimeter (D50=1 mm) was considered. In this research, a PVC pipe with an external diameter of 2.5 cm was used. The distance of the pipe from the bed (G) was considered based on a coefficient of the pipe diameter (0, 0.25, 0.5, 0.75, 1). Also, the insertion depth of the shield (Dw) was selected according to a coefficient of the pipe diameter (0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75 and 2). The results of the experiments showed that in the case that the shield was not used, with the increase in the distance between the pipe and the bed, the maximum scour depth under the pipeline decreases.