【摘要】 利用射流清淤在疏浚工程中已得到广泛的应用并发挥了重要的作用,探究工作射流条件和沙床边界条件对冲蚀效果的影响有助于疏浚设备的优化设计及提高疏浚效率。观测和分析了静止平面斜向射流在不同射流速度、射流角度及沙床坡度条件下冲蚀沙床的过程、冲坑形态、以及冲坑外浑水流动特征。结果表明:二维冲坑剖面存在几何相似性,几何形态不对称,整体向下游发展;冲坑发展过程可分为初始、发展和稳定三个阶段,冲坑的深度随时间的变化呈对数关系增长,在冲坑深度达到最大深度一半时冲蚀速率最大;二维冲坑面积随射流角度的增大呈先减小、后增大的关系变化,在45°时存在极小值;泥沙冲蚀量、坑外浑水流运动速度随着沙床坡度的增大而增加,而坡度大于10‰后冲蚀量增长趋势趋缓。更多还原

【Abstract】 The utility of jet dredging has been widely used and played an important role in dredging projects.It is important to explore its results with different jet factors and dredging factors,which can improve dredging efficiency.In this paper,the erosion processes of sand beds with different slopes by the plane jet with inclined angles were investigated with different jet velocities,jet angles and slopes of sand bed,shapes of scour holes,and characteristics of turbid flow outside the crater.The results showed that:(1)There were geometric similarities of the scour holes with asymmetrical geometry and downstream-toward profiles;(2)The development processes of the scour holes can be divided into three stages:initial stage,development stage and stable stage;(3)The depth of the scour holes developed with time as a logarithmic relationshp,and the erosion rate reached the largest when the crater depth reaches half of the maximum depth;(4)With the increase of jet angle,the areas of two-dimensional crater decreased firstly and then increased.It reached its minimum value when the jet angle was at 45°;(5)The volumes of sediment erosion and the speed of turbid flow outside the crater increased with the slopes of the sand bed.However,the growth trend slowed down after the slope was greater than 10‰.更多还原