空心四面块体促淤堤近底水动力特性试验研究*

依据长江口某促淤工程的设计条件及物理模型试验方法对空心四面块体促淤堤近底水动力特性开展研究。结果表明：1）近底紊动强度最大值所在位置、近底水平时均流速最小值所在位置以及近底水平时均流动方向的转变位置基本重合；2）对于某种具体堤型而言，在相同单宽流量条件下，随着相对水深的变化（至少在本文试验范围内），其紊动强度最大值所在位置比较稳定；3）与抛石加护面块体促淤堤相比，透水性较好的堤身结构近底紊动强度最大值所在位置会更加远离堤轴线，可使局部冲刷坑更加远离堤轴线，对堤身结构稳定有益。

Experimental study on near-bottom hydro-dynamic characteristics of hollow tetrahedron siltation promotion embankment

According to the design conditions of a siltation promotion project located in the Yangtze River estuary,the near-bottom hydrodynamic characteristics of a new hollow tetrahedron siltation promotion embankment is studied by model-test method.Test results show that:1)The maximum value of the near-bottom turbulence intensity,the minimum value of the near-bottom average horizontal velocity,and the direction changing of the near-bottom average horizontal velocity occurs almost at the same place;2)For a concrete dam type,the maximum value of turbulence intensity occurs almost at the same place under the same unit discharge condition when the relative water depth changes;3)Compared with traditional embankment which is composed of riprap and armor block,embankment structures with better permeability can be more beneficial for the stability,because the maximum value of the near-bottom turbulence intensity is farther away from the dam axis which makes the local scour hole further away.