坡面细沟流侵蚀临界条件研究

Critical Conditions for Rill Flow Erosion on Hillslopes

从适用于陡坡的水动力学模型出发,研究坡面水流细沟侵蚀临界状态的判断方法。讨论了坡长、坡度、坡面投影长对细沟侵蚀的影响,采用临界摩阻流速随坡度变化、临界摩阻流速不随坡度改变两种假定分别进行模拟计算,以摩阻流速作为判别坡面细沟流侵蚀临界状态的水动力学指标,在给定的坡面尺寸、净雨强和初始微地形条件下,计算得出了细沟流摩阻流速达到临界值时所对应的坡度。

Critical conditions for rill flow erosion on hillslopes are investigated using numerical simulation and laboratory data for large variation in slope gradients. Several factors have been considered in this study, i.e., slope length, gradient, projected length on a horizontal plane, etc. Shear velocity is used as the parameter for establishing a critical condition, and two cases have been considered,i.e.,(1) the critical shear velocity may change with slope gradient, or (2) it may not change. For given plot size, net rainfall intensity and original topography, the minimum slope gradient has been found out at which shear velocity of rill flow can achieve the critical value.