Xiong Wen, Cai C S, Kong Xuan
Department of Bridge Engineering, School of Transportation, Southeast University, Nanjing, China.
Appl Opt. 2012 Feb 10;51(5):547-57. doi: 10.1364/AO.51.000547.
Scour is one of the main causes of bridge failures. In order to measure and monitor scour depth variations including deposition (refilling) process, three designs for a scour monitoring system using fiber Bragg grating (FBG) sensors are discussed in the present study. By a comparative study, one of them is recommended in the present study and its instrumentation manufacture process is also introduced in detail. Using this recommended design, the advantages of FBG sensors for monitoring, such as immunity from electromagnetic interference and multiplexing capability, can be fully utilized. Both scour depth variations and entire scour development process including deposition process can be correctly monitored in real-time by continuously identifying the locations of emerging FBG sensors from the riverbed. A reliable sensor protection measure is also designed for FBG sensors in harsh environments, especially in floods. Finally, a verification test using a flume is carried out in the laboratory and three experimental cases are conducted to demonstrate the capability of FBG sensors and applicability of the recommended scour monitoring system. It can be concluded that the recommended scour monitoring system using FBG sensors is capable of measuring the water level, (maximum) scour depth, entire process of scour development, and deposition height due to refilling process. The advantages over other conventional scour monitoring systems are clearly demonstrated.
冲刷是桥梁失效的主要原因之一。为了测量和监测冲刷深度变化，包括淤积（回填）过程，本研究讨论了三种使用光纤布拉格光栅（FBG）传感器的冲刷监测系统设计。通过对比研究，本研究推荐了其中一种设计，并详细介绍了其仪器制造过程。采用这种推荐设计，可以充分利用FBG传感器在监测方面的优势，如抗电磁干扰能力和复用能力。通过持续识别河床中出现的FBG传感器的位置，可以实时正确监测冲刷深度变化以及包括淤积过程在内的整个冲刷发展过程。还针对恶劣环境（尤其是洪水环境）中的FBG传感器设计了可靠的传感器保护措施。最后，在实验室中使用水槽进行了验证测试，并进行了三个实验案例，以证明FBG传感器的能力和推荐的冲刷监测系统的适用性。可以得出结论，推荐的使用FBG传感器的冲刷监测系统能够测量水位、（最大）冲刷深度、冲刷发展的全过程以及回填过程导致的淤积高度。与其他传统冲刷监测系统相比，其优势得到了明显体现。
