Abstract Trackside monitoring of railways provides useful data for understanding the condition and mechanical behaviour of railway track, prior research has shown that railway track performance varies significantly along its length, primarily owing to changing support conditions. Understanding the changing performance along track offers the potential for improved track design and maintenance. Different technologies are used to investigate this. For example, inertial sensors, or high-speed filming with digital image correlation (DIC) for track deflection, and traditional strain gauges for loads. The latter usually rely on in-situ calibration. These techniques are suitable for measurements at discrete locations along the track length but are not suited to measuring performance variability even along a few hundred meters of a railway line. This paper investigates the use of a recently developed sensing system known as distributed acoustic sensor (DAS) that uses optical fibres. This method has the potential to be used over very long lengths of track; offers high sample rates; and has a gauge length and spatial resolution suitable for investigating the load-deflection behaviour of the track. This study presents DAS optical fibre strain measurements from a study site and presents novel methods for determining the rail deflection and the load per sleeper end. The DAS results are compared with point location measurements using a traditional strain gauge and deflections determined using imaging and DIC. The DAS system offers reliable distributed strain measurement that convert to estimates of track deflection and load with the potential for continuous spatial and temporal coverage over significant lengths of track.

中文翻译：

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基于分布式光纤声学传感的铁路轨道行为分析

摘要 铁路轨旁监测为了解铁路轨道的状况和力学行为提供了有用的数据，先前的研究表明，铁路轨道性能沿其长度变化显着，主要是由于支撑条件的变化。了解轨道沿线不断变化的性能为改进轨道设计和维护提供了潜力。使用不同的技术来研究这一点。例如，惯性传感器，或具有用于轨道偏转的数字图像相关 (DIC) 的高速拍摄，以及用于负载的传统应变计。后者通常依赖于原位校准。这些技术适用于沿轨道长度的离散位置的测量，但不适合测量甚至沿几百米铁路线的性能变化。本文研究了最近开发的传感系统的使用，该系统称为使用光纤的分布式声学传感器 (DAS)。这种方法有可能在很长的轨道上使用；提供高采样率；并具有适合研究轨道的载荷挠度行为的标距长度和空间分辨率。本研究介绍了来自研究地点的 DAS 光纤应变测量值，并介绍了确定轨道挠度和每轨枕端载荷的新方法。将 DAS 结果与使用传统应变仪的点位置测量以及使用成像和 DIC 确定的挠度进行比较。