An advanced signal processing technique for deriving grain size information of bedload transport from impact plate vibration measurements
An advanced signal processing technique for deriving grain size information of bedload transport from impact plate vibration measurements
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一种先进的信号处理技术，用于从冲击板振动测量中获取底土输送的粒度信息
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发表时间：
2015
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通讯作者：
Reimar Schenkluhn
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作者：
J. Barrière;A. Krein;A. Oth;Reimar Schenkluhn
一个可靠的推移质输移特性是衡量工程和理论问题有关的河流泥沙输移动力学。然而，虽然在监测技术的发展方面取得了重大进展，但很难得出可靠的定量预测关系。在这篇文章中，我们开发了一种专用的信号处理技术，旨在提高使用的冲击板测量材料传输特性。我们的装置由安装在不锈钢板底部的压电水听器组成，因此可以作为“沉积物振动传感器”。虽然这种系统的经典分析通常限于相当简单的程序，如冲击计数，大量的有用信息包含在冲击信号的实际波形中，它传达了推移质施加在板上的力和接触时间。一种先进的信号处理技术，称为“第一次到达原子分解”是用来改善推移质输运的特性，通过分析的幅度和频率属性的每一个单一的影响。这种新的处理方法被证明是非常适合的推移质运输监测板系统，并允许我们建立一个中值粒径（D50）和影响信号属性之间的关系。这种联系首先通过受控水槽实验进行观察和验证，然后应用于洪水事件期间小型砾石床河流的连续冲击记录。估计的D50提供了一种新的可能性来观察推移质输运的随时间变化的粒度分布。版权所有© 2014约翰威利父子有限公司.
A reliable characterization of bedload transport is required to gauge the engineering and theoretical issues related to the dynamics of sediments transport in rivers. However, while significant advances have been made in the development of monitoring techniques, robust quantitative predictive relationships have proven difficult to derive. In this article, we develop a dedicated signal processing technique aimed at improving the usage of impact plate measurements for material transport characterization. Our set‐up consists of a piezoelectric hydrophone mounted on the bottom side of a stainless steel plate, thus acting as a ‘sediment vibration sensor’. While the classical analysis with such systems is usually limited to rather simple procedures, such as impact counting, a large amount of useful information is contained in the actual waveform of the impact signal, which conveys the force and the contact time that the bedload imposes on the plate. An advanced signal processing technique called ‘first arrival atomic decomposition’ is used to improve the characterization of bedload transport by analysing the amplitude and frequency attributes of each single impact. This new processing approach proves to be well suited for bedload transport monitoring using plate systems and allows us to establish a relationship between the median grain size (D50) and the impact signal properties. This link is first observed and validated with controlled flume experiments and then applied to continuous impact records in a small gravel‐bed river during a flood event. The estimated D50 offers a novel possibility to observe the time‐varying grain size distribution of bedload transport. Copyright © 2014 John Wiley & Sons, Ltd.