Anti-scour performance of fluidized solidified slurry in dynamic water for scour repair

Abstract

A novel method using fluidized solidified slurry for scour repair and protection around offshore foundation has been proposed recently. After being pumped to seabed area around foundation for scour protection or into the developed scour holes for scour repair, the fluidized solidified slurry is kept around the foundation for solidification which is still at a vulnerable state experiencing erosion and scour in the dynamic ocean water environment. Moreover, a reliable evaluation of loss of fluidized solidified slurry in scour repair or protection design using the new method requires to consider both the loss in pumping operation and solidification. Therefore, anti-scour performance of fluidized solidified slurry during solidification process is key for the novel technology. The current work conducted a series of experimental tests using a self-designed specially-targeted flume testing device to study the effects of flow property of fluidized solidified slurry and flow velocity of dynamic water on the anti-scour performance of solidified slurry in solidification under current. The retention rate of solidified slurry and scouring state were evaluated and discussed. Results indicates that the flow value that describing the pumpability of fluidized solidified slurry, is a key factor which affecting the critical starting velocity that characterizing the critical state of incipient motion. The critical starting velocity decreases with the flow value of fluidized solidified slurry. When the water flow velocity of current is larger than the critical starting velocity, the loss of fluidized solidified slurry is great, which can be evaluated by the retention rate. Empirical formulas for calculating the critical starting velocity and retention rate of fluidized solidified slurry in solidification was then proposed for the performance evaluation of fluidized solidified slurry application under current.