عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In this research, the effect of applying sacrificial piles on local scour around square piers is studied. The sacrificial piles are placed at upstream of a bridge pier for the purpose of protecting it from local scour by deflecting the high-velocity flow, reducing vortex system power and creating a wake pressure region behind themselves. In this study, the effect of size of sacrificial piles and spacing between them was investigated in a 7.3 m long, 0.56 m wide and 0.6 m deep flume, under clear-water condition. The diameter (D) of square pier was 40 mm. The experiments were conducted on three sizes of sacrificial pile’s diameters (d) of 32, 27 and 20 mm, and three different distance of 2.8D, 2.95D and 3.1D from the upstream face of the pier with Froude number equal to 0.13, 0.16 and 0.19. The result showed that in a given distance with increasing the sacrificial pile diameter, the scour depth reduces, significantly. Also, in all of the circumstances, the scour depth increased with increasing the Froude number. Furthermore, the results showed that the best location of sacrificial pile was at a distance equal to 3.1D of the pier (X), that led to a significant reduction in local scour about 70 to 132% related to pile diameter and flow intensity.