护岸糙率对梯形河道行洪能力的影响研究

采用仿真草皮和三棱柱砖块模拟生态护岸,通过水槽试验研究了变流量和变底坡工况下梯形河道中护岸糙率的变化规律。通过数值模拟的方法,研究了非均匀流及不同宽深比情况下护岸糙率对河道水面线的影响。结果表明:河道综合糙率随水深的增加而增大,符合对数分布规律,改变流量或底坡对护岸糙率值影响不大;均匀流与非均匀条件下,河道水深均随着护岸糙率的增大而增加;非均匀流条件下,沿程综合糙率与沿程水深呈正相关;护岸糙率较大范围的变化,对宽深比较小的河道水深有较大影响,而对宽浅河道的行洪能力影响不大。

The Influence of Revetment Roughness on Flood Carrying Capacity in Trapezoidal Open Channel

Artificial turf and triangular prism brick are adopted to imitate ecological revetment,and the roughness coefficient of trapezoidal open channel flow with revetment is investigated based on the experiments conducted in an asymmetric trapezoidal flume with different flow rates and bed slopes,the influence of revetment roughness on flood carrying capacity in trapezoidal open channel under non-uniform flow and different wide-depth ratios is analyzed based on numerical simulation.The results show that,the composite roughness increases with an increase in flow depth,and conforms to the logarithmic profile,while the variation of flow rate or bed slope has no obvious effect on roughness coefficient.Under both the uniform flow and non-uniform flow,the flow depth increases with an increase in composite roughness;in the non-uniform flow,the stream-wise variation of composite roughness has the positive correlation with the stream-wise variation of water depth.The impact of revetment roughness on flood carrying capacity is obvious in the narrow and deep river while it is not significant in the wide-shallow river.