工程堆积体坡面植物篱的控蚀效果及其机制研究

发布时间：2018-08-23 10:24

【摘要】：工程堆积体极易产生水土流失,是生产建设项目水土流失防治的重点。为探明工程堆积体植物篱控蚀效果和机理,通过野外模拟径流冲刷试验,该文采用35、45、55 L/min 3种放水流量,对24°、28°、32°三种坡度的植物篱(H)及裸露对照小区(C)堆积体边坡(20 m×5 m标准监测小区)进行模拟放水冲刷试验,选取产沙率、径流含沙量、减沙量、径流挟沙力、剪切力、剥蚀率和径流功率等因子对堆积体坡面植物篱的控蚀效果及其机理进行分析。结果表明:堆积体侵蚀时间段集中在产流中后期(10~32 min),侵蚀位置主要在坡面中上段(0~10 m),植物篱具有10%~45%的减沙效益,其控蚀能力与冲刷历时之间存在二次函数的关系,临界时间随坡度和流量的增加而提前;植物篱坡面产流后期径流含沙量超过裸坡,这与其在侵蚀过程中的"源-汇"转变有关;植物篱可降低坡面土壤剥蚀率,提高坡面的临界剪切力和临界径流功率,能抑制细沟向坡面下部的发育,基于径流功率,其可蚀性参数(3.58 g/(N·m))大于对照坡面的可蚀性参数(2.83 g/(N·m))。研究结果可为坡面植物篱的合理利用提供一定的理论支撑,也能为工程堆积体措施条件下土壤侵蚀预报模型的建立提供部分参数支持。
[Abstract]:Engineering accumulations are easy to produce soil erosion, which is the key point of soil erosion prevention and control in production and construction projects. In order to find out the effect and mechanism of plant hedgerow erosion control in engineering, through field simulated runoff scour test, three kinds of water discharge flow of 35 ~ 455 ~ 55 L/min were used in this paper. The simulated flushing experiments were carried out on hedgerow (H) with 24 掳and 28 掳~ 32 掳slope and (C) accumulation body slope in bare control plot (20 m 脳 5 m standard monitoring plot). The sediment yield, runoff sediment content, sediment reduction, runoff sediment carrying capacity and shear stress were selected. The erosion control effect and its mechanism of hedgerow were analyzed by erosion rate and runoff power. The results show that the accumulation erosion time period is concentrated in the middle and late stage of runoff (10 ~ 32 min),) erosion position is mainly in the middle and upper section of the slope (0 ~ 10 m),) hedgerow has 1045% sediment reduction benefit, and there is a quadratic function relationship between erosion control ability and erosion duration. The critical time is advanced with the increase of slope and flow, the runoff sediment content of hedgerow is higher than that of bare slope in the late stage of runoff, which is related to the "source-sink" transition in the process of erosion, and hedgerow can reduce the erosion rate of soil on the slope. Increasing critical shear stress and critical runoff power can inhibit the development of the lower slope of the rill slope. Based on the runoff power, the erodibility parameter (3.58 g / (N m) is higher than that of the control (2.83 g / (N m). The results can provide some theoretical support for the rational utilization of hedgerows on slope surface, and also provide some parameter support for the establishment of soil erosion prediction model under the condition of engineering accumulation measures.
【作者单位】：中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室;中国科学院大学;西北农林科技大学水土保持研究所;
【基金】：国家自然科学基金:工程堆积体陡坡坡面径流侵蚀输沙动力过程试验研究(41671283) “十三五”重点研发计划:高塬沟壑区固沟保塬生态防护与苹果产业提质增效技术及示范(2016YFC0501706-02)
【分类号】：S157

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