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为采用水力学参数特性揭示黄土高原沟壑区工程堆积体坡面土壤侵蚀过程,开展了野外放水冲刷试验。通过组合不同流量(35、45、55L/min)、不同坡度(24°、28°、32°)的试验,对坡面沟蚀发生发展过程中的水力学参数特性进行了研究。结果表明,坡面细沟水流的平均流速与水深主要受流量控制,二者均与单宽流量呈幂函数关系,且流速随冲刷时间的持续和冲刷形态的变化呈现上下起伏—瞬时增大—稳定的波动或减小—趋于稳定的变化历程。在所有坡度和流量范围内,雷诺数Re在42.9~1 082.8之间变化,雷诺数Re随坡度的增大呈先减小后增大的抛物线趋势。由坡面流弗劳德数Fr随冲刷历时变化情况表明,坡面径流形态是由急流向缓流发展。阻力系数f在0.019~0.94之间变化,f随坡度的增加先减小后增加,且随雷诺数Re的增大而增大,二者之间呈显著的指数函数关系。粗糙系数n随雷诺数增大而增大,且其与雷诺数存在显著性的指数函数关系。研究结果可为工程堆积体土壤侵蚀预报模型的建立提供一定的参数,对解决生产建设项目弃土弃渣场、取土场等水土流失问题具有重要的作用。
In order to reveal the process of soil erosion on the slope of pile body in the gully area of Loess Plateau by using the characteristics of hydraulics parameters, the scouring experiment of field drainage was carried out. The characteristics of hydraulic parameters during the development of gully erosion were studied by combining different flow rates (35,45,55 L / min) and different slopes (24 °, 28 °, 32 °). The results show that the average flow velocity and water depth of rill flow on slope are mainly controlled by flow rate, both of which have a power function relationship with single-wide flow rate. The flow velocity changes up and down with the duration of scouring and the morphology of scour - Stable volatility or reduction - tends to stabilize the course of the change. Reynolds number Re varies from 42.9 to 1082.8 in all slope and flow ranges. The Reynolds number Re first decreases and then increases with the increase of gradient. From the change of the Froude number Fr with the lapse of time, the runoff form of the slope surface is developed from the rapid flow to the slow flow. The drag coefficient f varies from 0.019 to 0.94, f decreases first and then increases with the increase of gradient, and increases with the increase of Reynolds number Re, which shows a significant exponential function. Roughness coefficient n increases with Reynolds number, and it has a significant exponential relationship with Reynolds number. The research results can provide some parameters for the establishment of the model of soil erosion prediction for the project accumulations, and play an important role in solving the problems of soil and water loss such as spoil dumping and borrow borrowing in the production and construction projects.