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通过组合不同坡度(10°、15°、20°、25°)、不同坡长(5、10m)、不同雨强(1.5、2mm/min)的室内纯净水模拟降雨试验,对坡面细沟侵蚀发生过程中的坡面流速的沿坡变化进行了研究,并讨论了流速与坡面含沙量的关系。试验结果显示:从坡顶至坡脚,坡面细沟流的速度逐渐增加;坡面流速主要受雨强和其流动距离影响,与坡度无关,并得到流速与雨强和距坡顶距离的关系式。坡面含沙量与坡度、雨强和坡面流速相关,而10m坡长所测的含沙量与5m坡长相近。将坡面流的能量分配为自身流动所需能量、剥蚀土壤消耗能量以及携带搬运土壤所需能量,在一定坡长内,径流的能量足以剥蚀并携带搬运坡面土壤,但超过此范围,虽然流动速度在增加,但是径流消耗于携带搬运泥沙的能量也增加,从而使坡面流的能量不足以支撑剥蚀土壤耗能,而坡面含沙量不会有显著的增加。
Through the simulated rainfall experiment of indoor pure water with different slope (10 °, 15 °, 20 °, 25 °), different slope length (5,10m) and different rainfall intensity (1.5,2mm / min) The change of slope along slope during erosion process was studied, and the relationship between flow rate and sediment concentration was discussed. The results show that the velocity of rill flow increases gradually from slope top to slope foot. The slope flow velocity is mainly affected by rainfall intensity and its flow distance, and has nothing to do with slope, and the relationship between velocity and rainfall intensity and the distance from slope top Relationship. Sediment concentration is related to slope, rainfall intensity and slope velocity, while the sediment concentration measured at 10m slope length is similar to 5m slope length. The energy of the slope flow is distributed as the energy required for its own flow, the erosion of soil energy consumption and the energy required to carry the soil. Within a certain slope length, the energy of runoff is enough to erode and carry the soil on the slope, but beyond this range, The flow rate is increasing, but the runoff consumes more energy to carry sediment, so that the energy of slope flow is not enough to support the energy consumption of denuded soil, and the sediment concentration on the slope will not increase significantly.