Experimental Study of Subaqueous Sand Deposition from Slurry Wall Jets

This paper presents the results of a laboratory study on the subaqueous deposition of sand particles from sediment-laden circular jets on horizontal and inclined beds. Four sets of experiments were carried out to investigate the effects of jet characteristics, bed slope, sediment size, and sediment concentration on the growth and development of the sediment mound. Three distinct flow regimes can be identified as developing regime, spreading regime, and backup regime. It was found that in the developing regime, deposition height and width formed by the continuous release of sediment particles grow faster than the mound length. Slurry jet flow in the spreading regime was diverted from the axial direction to the sides and caused more deposition on both sides of the mound. Backup regime started when the deposition height and width reached their maximum values. In this condition, a slurry jet pushed sediment back to the nozzle and eventually blocked the flow. The initiation of sediment deposition was estimated, and predictions were compared with experimental results. Variations of the deposition length scales, mound base area, and angle of deposition with time were measured. Empirical formulations were introduced to predict deposition development with time.