崩岗崩积体陡坡侵蚀的水动力学特征

Hydrodynamic characteristics in steep colluvial deposits slope

以花岗岩发育形成的崩岗崩积体为研究对象,通过不同流量(3.6、7.2、10.8、14.4 L·min-1)和陡坡坡度(20°、25°、30°、35°、40°)相结合的室内放水冲刷试验,对崩积体坡面侵蚀的动力学参数进行分析,以探讨崩积体坡面的侵蚀水动力机理。结果表明,坡面水流流速随坡度和流量的增大均呈增大趋势,可由流量和坡度呈幂函数进行表达,坡度对流速的影响小于流量,输沙率随流速增大呈线性函数增加;随着流量和坡度的增加,水流剪切力、单位水流功率和断面单位能量3个动力学参数整体呈增大趋势,流量对三者的影响作用均大于坡度;输沙率与3个水动力学参数均呈线性函数关系,可首选单位水流功率作为崩积体冲刷侵蚀的水动力学参数。

This study aimed to investigate the dynamic characteristics in a granite colluvial soil slope under different discharge and slope gradient conditions. Discharge ranged from 3.6 L-min-1 to 14.4 L· min-1 and slope gradient from 20° to 40°. The main conclusions were as follows. The flow velocity increased with the discharge and slope gradient increasing, and couble be predicted by the discharge and slope gradient with a power function. The effect of slope gradient was lower than discharge on flow velocity. A linear function fitted the data for the relationship between sediment yield rate and flow velocity. The shear flow, unit stream power and specific energy increased with the discharge and slope gradient increasing on the whole, and discharge had greater effects than slope gradient on them. Sediment yield rate had a linear function with the three hydrodynamic parameters, the unit stream power could be the primary choices as the dynamic parameter of sediment transportation on colluvial depodit slope.