| On the basis of consulting a large number of literatures domestic and aboard, the present situation and latest development of hydrodynamic characteristics of overland flow and slope erosion dynamic process were reviewed. Aiming at revealing the effect of rainfall splash intensity on hydrodynamic features of sheet flow and slope erosion, with a combination of runoff experiment and simulated rainfall experiment with a fixed intensity, applying hydrodynamic and erosive theory, the effect of rainfall on overland flow velocity and the influence of rainfall splash intensity on hydrodynamic features (such as velocity, flow depth , flow patterns, resistance) of sheet flow on slope and the influence of rainfall splash intensity on the overland flow sediment contain was researched. By means of the study the main results are listed as follows:(1) The results of flume experiment and simulated rainfall experiment with a fixed intensity indicated that, the influencing degree of rainfall on overland flow velocity had something to do with the runoff discharge above and rainfall intensity. The raindrop splash would accelerate the velocity of shallower flow under a smaller flow discharge, and the higher rainfall intensity, the greater extent the flow velocity augmented. Under a bigger flow discharge, the raindrop splash would slow down the velocity of the overland flow, and the higher rainfall intensity, the smaller extent the flow velocity decreased.(2) The effect of rainfall splash intensity on hydrodynamic features of sheet flow indicated that, the former had a remarkable effect on the latter. The results of flume experiment indicated that, the flow velocity and Froude number of the overland flow would fall with the rainfall splash intensity rose; The flow depth and resistance coefficient would enhance with the rainfall splash intensity increased. The results of soil trough experiment indicated that, the flow velocity and Froude number would add when the rainfall splash intensity rose; The flow depth and resistance coefficient would decrease when the rainfall splash intensity increased. Through analysis, the phenomenon was thought to have something to do with the absorbed energy of sheet flow on the different slope.(3) The results of soil trough experiment and simulated rainfall experiment with a fixed intensity indicated that, the rainfall splash intensity had a remarkable effect on the overlandflow sediment contain .During the single rainfall experiment, when the rainfall splash height was less than 5 meters, the overland flow sediment contain would add with the lower rainfall splash height increased; when the rainfall splash height was more than 5 meters, it would drop with the higher rainfall splash height increased. During the rainfall experiment with a flow discharge, the influencing degree of rainfall splash intensity on the overland flow sediment contain had something to do with the runoff discharge above. Under the less flow discharge, the rainfall splash intensity didn't almost have a remarkable effect on the overland flow sediment contain, Under the greater flow discharge, the overland flow sediment contain would increase with the rainfall splash intensity rose. |
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