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首页> 外文期刊>Water resources research >Experiment on temporal variation of bed load transport in response to changes in sediment supply in streams
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Experiment on temporal variation of bed load transport in response to changes in sediment supply in streams

机译：响应河流泥沙供应变化的河床负荷输运随时间变化的实验

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A flume experiment was conducted to study channel adjustment to episodic sediment supply in mountain streams. The bulk sediment used for the bed and feed included grain sizes 0.5-64 mm with geometric mean D g(bulk) of 5.7 mm. Water discharge was held constant for 40 h, and 300 kg of sediment was supplied through a range of scenarios. Bed slope, sediment storage, sediment transport, and bed surface texture responded to sediment supply. During the first of seven runs, bed slope decreased from 0.022 m /m (flume slope) to 0.018 m /m due to sediment starvation. Bed slope increased beginning in the second run as the bed aggraded due to preferential storage of grains >8 mm. Transport rate and bed-surface particle size were significantly affected by magnitude-frequency of sediment feed. Under constant feed, transport rate increased gradually and D g(surface) ranged between 12 and 15 mm. Instead, sediment pulses caused a pronounced increase in sediment transport rate and surface fining, trends that were inverted as sediment evacuated. At the run scale, sediment transport and storage behaved as with constant feed if pulse relaxation time exceeded time between pulses. The increase in transport rate and surface fining were proportional to pulse size. After the 300 kg pulse, transport rate reached 100gm-1s-1 and D g(surface) was <10 mm. After 75 kg pulses, transport rate reached approximate to 10gm-1s-1 and D g(surface) was >12 mm. Textural differences on the initial bed surface influenced the patterns of sediment transport. Channel adjustment was controlled by magnitude-frequency of sediment feed and not by total feed.
机译：进行了水槽实验，以研究山间溪流的沉积物供应渠道调整。用于床和饲料的大量沉积物的粒度为0.5-64毫米，几何平均D g（堆积）为5.7毫米。排水保持恒定40小时，并通过一系列方案提供了300公斤的沉积物。床的坡度，沉积物的存储，沉积物的运输和床的表面质地对沉积物的供给有反应。在七个运行的第一个过程中，由于沉积物匮乏，河床坡度从0.022 m / m（水渠坡度）下降到0.018 m / m。由于优先储存> 8 mm的谷物，从第二次运行开始，随着床层的堆积，床坡度增加。输沙速率和床面粒径受沉积物进料量级频率的显着影响。在恒定进料下，运输速率逐渐提高，D g（表面）在12至15 mm之间。取而代之的是，沉积物脉冲导致沉积物传输速率和表面细化明显增加，随着沉积物被抽空，这种趋势被逆转了。在运行规模上，如果脉冲弛豫时间超过两个脉冲之间的时间，则沉积物的输送和存储表现为恒定进料。传输速率和表面细化的增加与脉冲大小成正比。 300 kg脉冲后，传输速率达到100gm-1s-1，D g（表面）<10 mm。 75 kg脉冲后，传输速率达到约10 gm-1s-1，D g（表面）> 12 mm。初始河床表面的质地差异影响了沉积物的运输方式。通道调节是通过沉积物进料的量级频率而不是总进料来控制的。

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