An Experimental Study on the Effect of T Shape Spur Dike on Down Sream Topography in a 90 Degree Bend

مهندسی عمران فردوسی

Article 8, Volume 22, Issue 1, 2011, Pages 113-128   

Document Type: پژوهشی

DOI: 10.22067/civil.v22i1.9040

Authors

mohamad Vaghefi^* ; masod Ghodsian

Abstract

One of the common methods of river training and bank protection is using spur dikes. Building spur dikes makes the flow path to be modified. Because of the concentration of flow in the middle part of the river it causes the river side not to be washed out. Setting spur dikes in the flow’s direction leads to a local scour in the spur dike site and the change in the bed’s topography of the bend down stream. this paper examines the effect bed’s topography around the T shaped spur dike located in a 90 degree bend by conducting several tests. These tests were carried out in an experimental channel with a bend of 90 degrees and under conditions with clear water. These experiments, in fact, measured the effects of such parameters like the length of the spur dike, the location of the spur dike in the bend, the flow Froud number on the down stream bed topography. The results of investigation show that two scour hole forms due to a T shaped spur dike. One at the nose of spur dike and the other one at the downstream of the spur dike. By increasing the length of the spur dike, the dimensions of first scour hole increase. But the dimensions of second scour hole decrease. By increasing the length of the spur dike the distance of location of second scour hole from the spur dike increases.Any change in the position of the spur dike toward the down stream of the bend, increases the dimensions of scour hole. Also, New equations for maximum scour depth and scour volumeat a T shaped spur dike are developed

Keywords

T Shape Spur Dike; Scour Hole; Bed Topography; Maximum Scour; Down Stream Hole

References