Experimental study on the hydrodynamic characteristics of a geomembrane-enveloped concrete structure of ecological revetment
Traditional revetment projects emphasize the durability and regulation effect but rarely consider river ecology and environment demand. Therefore, a new geomembrane-enveloped concrete structure of ecological revetment was put forward by waterway designers on the basis of dissipating the near bottom flow velocity, which could reduce the velocity through the block and shelter effects of the concrete structure and then form a moderate hydrodynamic environment benefitting sediment deposition and plant growth. An hydrodynamic experiment was carried out in a variable-slope flume to accurately measure the local flow conditions around the concrete structure by a three-dimensional velocity meter (Vectrino). The results indicate that due to the block effect, the longitudinal velocity dissipation rate of the designed structure reaches 68.4% and will further increase to 86.1% because of the block effect of the growing plants. Compared with the incoming flow, the turbulence intensity inside the lattice increases relatively, whereas the sharp dissipation of the flow velocity could form a moderate flow environment, which can prevent the erosion of nutrient soil on the slope. The near-bottom turbulence intensity will further reduce after plant growth, which is conducive to the protection of nutrient soil.