Study on flow and sediment dynamics and deposition characteristics of hollow block

Hollow blocks have good water blocking and siltation promotion functions, and have been widely used in ecological restoration projects in recent years. In this paper, combined with flume experiment and Flow-3D numerical simulation, the water blocking effect and sedimentation characteristics of open and semi-closed hollow blocks are analyzed. The results show that the permeability of the hollow block plays a leading role in the internal flow velocity and turbulence intensity, and the semi-open hollow block with small permeability has a better effect in slowing down and turbulence control. The suspended sediment concentration near the bottom of open and semi-closed hollow blocks increases by 56% and 75%, respectively. Both of them can promote the deposition of sediment in the block. The environment of low flow velocity, sediment micro-deposition and water and sediment connected inside and outside by hollow blocks is the habitat requirement of macrobenthos, the structure of low turbulent flow inside the semi-enclosed hollow block is more favorable for the habitat and reproduction of macrobenthos.