涌潮条件下排桩式低丁坝水力学冲淤试验研究

Erosion and siltation study for low sheet-pile groins under tidal bore

本文在水槽中用动床模型试验手段研究了涌潮条件下不同透水率的排桩式护塘低丁坝群的水力学冲淤特性 ,并探讨了低丁坝的护滩保塘机理。结果表明 ,不透水的排桩式丁坝群 ,其坝田部位可减冲 1～ 1.6m,与相应方案的堆石坝研究结果相近 ;随着板桩丁坝透水率的逐渐增大 ,滩地防冲作用逐渐变小 ,然而透水率大于 60 %的丁坝 ,仍有 0 .8m以上的减冲能力。低丁坝的保滩护塘机理主要体现在三个方面 :即对涌潮潮头的阻挡作用 ,对涌潮快水的减冲作用和在落潮期回流淤积作用本文除对护塘丁坝的设计提供基本数据外 ,还对新颖丁坝型式和结构的探讨有借鉴意义。

In this paper,erosion and siltation performance of low sheet-pile groins with different water permeability under tidal bore is studied by means of movable-bed model, and mechanism of flat-maintenance and dyke-protection is discussed. The result shows that low unpermeable sheet-pile groins could lessen erosion of 1~1.6 m deep in groin basin, which is close to that of the riprap groins. With the gradual increase of water permeability of low sheet-pile groins, the effect of flat-maintenance of low sheet-pile groins will gradually decrease. The groins that water permeability is greater than 60 percent could lessen more than 0.8 m deep erosion. Mechanism of flat-maintenance and dyke-protection of low sheet-pile groin has three principal aspects: blocking effect on the tidal bore front, alleviating erosion effect of the rapid flow of tidal bore and return-flow siltation effect during ebb tide The present paper could be used for reference of new-type groin structure as well as offer basic data for design.