不同形状丁坝河床特性试验研究

Experimental study on riverbed characteristics of spur dikes with different shapes

文中对不同类型丁坝在混合泥沙作用下的局部水流和河床变化进行了室内试验研究,分别研究了透水丁坝、不透水丁坝和3种混合丁坝在清水冲刷下的非淹没状态。重点讨论了丁坝类型不同所引起的局部冲刷和尾流沉积特性及泥沙粒径分布特征。结果发现,混合丁坝周围的水流结构和河床变化是透水丁坝和不透水丁坝的组合,在丁坝下游存在砂带现象,主要由横向泥沙分选引起。通过充分利用透水和不透水的丁坝水流模式和河床变化趋势,以期实现较为理想的水流模式和河床变化形态。

In this paper,laboratory experiments are carried out on the local flow and riverbed changes of different types of spur dikes under the action of mixed sediment,and the non-submerged state of pervious spur dike,impervious spur dike and three kinds of mixed spur dike under clean water scouring are studied respectively.The characteristics of local scour,wake deposition and sediment size distribution caused by different spur dike types are discussed emphatically.The results show that the flow structure and riverbed change around the mixed spur dike are the combination of permeable and impervious spur dikes,and there is sand zone in the downstream of the spur dike,which is mainly caused by the lateral sediment sorting.By making full use of permeable and impervious spur dikes flow patterns and riverbed changing trends,the ideal flow patterns and riverbed changing patterns can be achieved.