بررسي آزمايشگاهي عمق آب شستگي دماغه در آب شكن هاي توري سنگي سركج

A laboratory investigation on local scour around the head of L shape gabion groins

An usual method for river bank protection is using gabion groin structures. If this permeable structure is designed and constructed appropriately, it will control bank erosion and reclaims flood plain areas. Since there are some uncertainties in the determination of length, space and shape of gabion groins, this experimental project was performed. In this investigation a laboratory movable bed flume with 17m length, 1.5m width and 0.8m depth was used to study local scour around the head of unsubmerged gabion groins. Groins with two different shapes (L shape and straight groins) were constructed perpendicular to the flumeʹs wall. Two different lengths of groin, 15 and 22.5 centimeter (10 and 15 percent of width of flume) resulting in two contraction ratios (20% and 30%), four different spaces between successive groins (resulting in four ratios of space to length, S/L) and three different discharges with a constant bed material and slope were used in the experiments. Based on the experimental results, and using the dimensional analysis technique, a dimensionless relationship was derived for estimating local scour around the head of gabion groins.