Scour depth for different pile positions at the toe of a block ramp

This paper investigates the change in scour depth downstream of rock chutes for different ramp toe conditions. The scour process downstream of rock chutes has been an important research topic over the years. The present study deals with a typical experimental problem that was faced carrying out experiments in laboratory flumes. The experiments were carried out in the laboratory of the University of Pisa, Pisa, Italy. The block ramp offer resistance to the flow due to its rough surface. The ramp surface is simulated by gluing the granular materials on a inox steel sheet. It was observed that when the height of the pile at the toe of the ramp is changed in elevation the scour depth downstream of the ramp also changes. This phenomenon was investigated testing three different slopes IV: 10H, IV:6H and IV:4H. The granular materials used for the ramp and the stilling basin are homogeneous. It was found that the scour depth downstream of rock chutes is a function of the pile height at the toe of the ramp. A relationship is proposed to determine the scour depth and length for different pile height in the tested experimental range.