Experimental Study on Incipient Motion of Submerged Repelling Stone Spur dike and its prone area to failure

In this paper, the effects of various parameters on incipient motion of a repelling rubble-mound spur-dike are experimentally explored. To this end, the velocity of incipient motion is measured for a repelling rubble-mound spur-dike with various angles composed of 100, 110 and 120 degrees, various mean particles diameters (i.e. 3.55, 7.1 and 11mm) and various percentage of submergence (i.e. 31.2, 50 and 68.7%). To observe prone area of the spur-dike to failure during the experiments, all the process was recorded using a video camera. Moreover, a vectorino Doppler velocimeter was used to measure velocity field around rubble-mound spur-dike. Results show that 10% increase in repelling rubble-mound spur-dike installation angle results in 5.35% decrease in failure threshold. It is also observed that the intersection of upstream or downstream sides with frontal side of spur-dike are prone area to failure. ADV measurement show that these areas are those areas where the highest values of turbulent kinetic energy and Reynolds stresses occurs. In fact, the highest value of in the interaction of upstream side and frontal side, along the shear layer happens which can cause spire-dike failure Moreover, negative values of and leads to stone accumulation behind the spur-dike.