水库溯源冲刷模式初探

An Experiment Study on the Form of Headwater Erosion in Reservoir

本文在原型观测的基础上,结合室内试验,分析了水库的溯源冲刷过程,认为水库溯源冲刷具有两种模式——“全程剥蚀”式溯源冲刷及“局部跌坎”式溯源冲刷,文中通过对一般水库淤积物粒径分布范围及淤积结构进行分析,选取了三组级配的沙样进行了水槽试验,由水槽斌验可知,当淤积体干容重小于1.2～1.25t/m^3时,溯源冲刷呈“全程剥蚀”式;当淤积体干容重大于1.2～1.25t/m^3时,溯源冲刷则呈“局部跌坎”式。这个结论已被一些水库实测资料验证是正确的。此外,文中还指出,目前用于溯源冲刷计算的数学模型只能用于“全程剥蚀”式溯源冲刷过程中,不能用于“局部跌坎”式溯源冲刷过程。而本文根据试验资料给出了后者的计算模式。

Based on the field observation and experimental data in laboratory, the process of headwater erosion in reservoir has been analyzed. Authorindicated that there are two kinds of patterns of headwater erosion-one is whole length erosion and another is local drop erosion. In order to find the quantitative limit which distinguishes two forms of headwated erosion,a lot of experiments were carried out by using three kinds of sediment sample. The experimental results show that the headward erosion will appear as a form of whole length erosion, when the value of the dry unit weight of deposited silt of reservoir is smaller than 1.2-1.25t/ m3; if larger, it will appear as a form of local drop erosion. This conclusion has been proved by some observed data of reserviors.In addation, it is pointed that the mathematical models to be used in caculating the head-ward erosion at present can only be used to whole length erosion, it is not suitable for caculating drop erosion.