摘要
水闸闸下冲刷问题较普遍地存在，冲刷破坏的部位绝大多数发生在消力池以下海漫和防冲槽处，严重破坏情况导致消力池被冲毁，危及整个闸室安全。冲刷破坏的原因很多，水闸过水断面缩窄过甚，翼墙扩散角不合适，闸门开启方式不当，消能设计条件不合理等。但是不论通过改进消能设计条件还是正确合理启闭闸门等措施，海漫及下游段的冲刷破坏情况依然不能彻底解决。经多年研究观察发现出消力池水流流速分布不均，近底流速偏大是造成这一现象的根本原因。我院文恒教授等经研究发现，利用废旧轮胎对海漫进行柔性加糙，可充分调整海漫下游流速分布，降低近底流速，对于解决闸下冲刷破坏，效果非常显著。
本文在延续前面海漫加糙试验研究的基础上，采用弹性较好的环状橡胶圈模拟废旧轮胎，在实验室人工水槽中进一步做海漫柔性加糙试验研究。试验共设计了21个加糙方案，采集加糙前后不同断面水流流速分布和水位状况，意在弄清在不同相对粗糙度情况下，加糙体的数量、尺寸、布置形式对加糙后的海漫糙率和近底流速有什么影响，寻找最优化可供实际设计采用的加糙体布置形式和尺寸等问题。
通过试验发现就环状橡胶圈（模拟废旧轮胎）这种柔性加糙体，垂直水流方向的投影面积是影响槽底糙率、水深和流速的主要因素。通过加糙使得海漫下游的近底流速明显减小，非常利于防冲。海漫加糙后壅高了消力池末端水深，在实际工程中可以减小消力池的深度。当相对粗糙度在0.394～0.581范围内，糙体梅花状等间距均匀布置，并非糙体数目越多越好，糙体8排左右对降低下游近底流速效果显著且趋于稳定。试验中还发现糙体间距在7～10.5 cm（k=△～1.5△）时，从实际设计应用对糙率、水深和近底流速影响等方面考虑都非常有利。
Destruction of erosion exists widespread and serious in most sluice gate on plains, and most take place in erosion control measure pitching and apron extension. In some serious the plunge pools be washed off, which nuisance the whole gate chamber. The reasons about washing off have many, cross section of the gate chamber contracting too much; the diffusion coefficient of wing abutment is unfit, condition of energy dissipation be unreasonable, and so on. You can change the condition of energy dissipation or sluice the gate in all kinds of methods, but the erosion phenomenon is still on and don’t make out efficiently. The professor Wen Heng and his students found that velocity of bottom of water is too much, and they found that roughened apron by waste tires can adjust velocity and lower velocity of bottom of water. This method can cope with the problem and the effect is significant.
This study was conducted on the base of the experiment of apron roughness increasing before, and used rubber turn which with good spring to simulate waste tires to fouler study apron flexible roughness in laboratory artificial flume. We designed 21 kinds of roughness increasing and place condition of water on different cross section. The aim was to fully understand the artificial roughness rubbers number, size/dimensions and assign form in different roughness relative, and the effect of it on the apron roughness and velocity of the bottom of water, and then found the optimum scheme of artificial roughness rubber’s form and dimensions, which could be used in practice.
By the testing we found the flexible artificial roughness rubber turns which simulated the wasted tires were the main factor which affect the roughness of the bottom which directed to vertical flow. By increasing roughness, the velocity of bottom of water decreased significantly, and could protect erosion very well. After increasing roughness of apron, the water rover at the end of plunge pool was increase/enhanced, therefore it could decrease the water height of plunge pool in practical program. When the relative roughness were between the arrange of 0.394 to 0.584. the arrangement of artificial roughness quincureioul form which with constant inter was not became well as the artificial roughness were increased, but was about 8 lines which could significantly decreasing velocity of the bottom of and tending stability. We also found that when the
interval of artificial roughness turns were 7-10.5 cm, it was advantage to rase of roughness, water level and the effect of velocity of the bottom of water considered from practical application.
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