堆积体作用下的河道最大冲刷深度

Maximum scour depth under action of deposit body

受地震、暴雨的影响,破碎的山体易发生滑坡、泥石流等,在河流岸边形成堆积体,改变了河道水流边界条件,在堆积体下游附近形成冲坑。本文通过动床水槽试验,研究了不同堆积体作用下的最大冲刷深度。结果表明,最大冲刷深度随流量、堆积体尺寸增大而增大。本文采用一些常见的丁坝、桥台最大冲深公式对试验成果进行了计算,但由于水流结构差异及公式适用范围限制,计算结果与实测值普遍相差较大。因此,本文参考丁坝、桥台冲刷深度计算的研究成果,充分考虑各影响因素作用,采用因次分析法,建立了堆积体作用下河道最大冲刷深度计算公式的基本形式,并根据实测资料拟合了公式参数。

A broken mountain likely develops landslides or debris flows induced by an earthquake or a rain storm. The disaster often forms large deposits near the river bank, which can exert influence on the river flow and produce scour downstream the deposit body. Based on the movable bed experiment, the maximum scour depths under the action of different deposit bodys are obtained. The results show that the scour depth increases with the flow discharge and the size of the deposit body. A lot of calculations by the equations for scour depth of spur dikes and abutments are acquired. Because of the difference of the flow structure and the application conditions of these formulas, the calculated results are quite different from our data. Based on studies of the scour depth of spur dikes and abutments, all factors are considered carefully. Finally, the basic form of the equation for scour depth of deposit is established based on the method of dimensional analysis, and the coeffi cients of the formula are established bv usin our experimental data.