Flume study of knickpoint development in stratified sediment
Flume study of knickpoint development in stratified sediment
复制标题
分层沉积物中小点发育的水槽研究
DOI：
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发表时间：
1976
期刊：
影响因子：
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通讯作者：
G. Pickup
中科院分区：
文献类型：
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作者：
W. N. Holland;G. Pickup
在一个水槽中研究层状沉积物中的断点发展，两个薄砂层之间的粘性材料层。砂床作为断点形成层位，在其上发展并维持阶梯状断点，因为它们向上游移动，形成了一个明显稳定的形式，包括一个通道中通道系统。该系统有四个基本要素：（1）在断点上游的加积河段，终止于下游端的充填-下切过渡区;（2）在断点面上方的过陡河段;（3）断点面;（4）下切河段，通常在连续的断点之间被移动的沉积物覆盖。
显然，存在一个断点形成层减少断点撤退率，这是远远低于在本研究中所观察到的粘性材料，但没有夹层砂床和类似的放电实验。此外，由分层引起的沟中沟系统显然对流量变化的影响相当不敏感。
In a flume study of knickpoint development in stratified sediment, two thin sand beds were intercalated between beds of cohesive material. The sand beds acted as knickpoint-forming horizons on which stepped knickpoints were developed and maintained as they moved upstream, creating an apparently stable form consisting of a channel-in-channel system. The system had four basic elements: (1) an aggraded reach upstream of the knickpoint, terminating on the downstream end at a fill-incision transition zone; (2) an oversteepened reach just above the knickpoint face; (3) the knickpoint face; and (4) an incising reach, often covered by moving sediment between successive knickpoints.
Apparently the presence of a knickpoint-forming horizon reduces knickpoint retreat rates, which were much lower in this study than those observed in an experiment with cohesive material but no intercalated sand beds and a similar discharge. Also, the channel-in-channel system that results from stratification is apparently fairly insensitive to the effects of changing discharge.