长江中游护滩工程边缘防冲促淤水草垫结构试验

Experiment of grass mat erosion control structure of beach protection engineering edge in middle of the Yangtze River

通过分析航道整治护滩工程边缘防冲促淤结构不足,提出水草垫结构,并开展定床和动床模型试验,研究不同倒伏程度、不同布置形式、不同水动力条件下水草垫的防冲促淤效果。结果表明:当流速较小时叶片弯曲幅度较小;流速增加至0.3 m/s时,叶片弯曲幅度较大;流速增至0.73 m/s时,叶片弯幅度增加较小。叶片倒伏60°情况,水草垫稀疏布置,防护效果较好;倒伏75°情况,水草垫密集布置,其防护效果较好。当来流速度较大时,水草垫区域内有较大淤积幅度,但淤积范围明显缩窄,侧缘坡度较陡,防护效果并不理想。在此基础上,确定了水草垫结构。

This paper puts forward a new grass mat structure after analysis of the insufficient of tradition erosion control structure of beach protection engineering edge.The paper carries out fixed bed and moving bed model tests to study the effects of different flattening degree, different layout and different current velocity on scour prevention.The results show that when current velocity is small, blade bending amplitude is small.Current velocity increases to 0. 3 m/s, and blade bending amplitude is large. While current velocity increases to 0. 73 m/s, blade bending amplitude increases lessly. When blade flattening degree is 60°, scour prevention effect of sparse arrangement mode is better.When it is 75°, scour prevention effect of close arrangement mode is better.However,when the current velocity is large, the erosion protection effect of grass mat will be less.Based on the researches, the paper determines the grass mat structure.