Performance evaluation of distributed strain sensing nerves for monitoring ground collapse: A laboratory study
来源：Measurement: Journal of the International Measurement Confederation
作者：Gao, Yuxin, Zhu, Honghu, Wei, Chao, Wang, Jing, Zhang, Wei
机构：南京大学
DOI：10.1016/j.measurement.2023.113100
【研究背景】
地面坍塌事件经常导致巨大的经济损失、灾难性伤害和人员死亡。因此，迫切需要敏感的监测技术来定位和预测潜在的地面坍塌。本研究旨在评估光纤（FO）电缆在地面坍塌监测中的性能。通过在实验室进行模型测试，结合光学频域反射测量（OFDR）和粒子图像测速法（PIV），监测整个坍塌过程。详细分析了在不同土壤破坏机制下，FO电缆测得的应变分布。
【研究内容】
在浅层天坑的情况下，土壤破坏面从天坑边缘开始，并最终传播到地面，破坏面的形状逐渐从曲线变为垂直。微型锚固显著增强了电缆与周围土壤的界面结合。此外，基于应变测量计算得出的沉降量与实际沉降量相吻合。
【研究意义】
本论文的创新点在于使用光纤监测技术对地面坍塌进行实时监测和预警。通过结合OFDR和PIV技术，我们能够全面了解地面坍塌的过程和机制。研究结果表明，在不同的土壤破坏机制下，FO电缆能够准确测量应变分布，并且通过计算得出的沉降量与实际情况相符。这一研究对于地质灾害预防和减灾具有重要意义，为提高地面坍塌监测的精确性和可靠性提供了新的方法和技术支持。 这项研究为我们提供了更深入的了解地面坍塌过程的机制，为预防和减少地质灾害的发生提供了重要的参考。未来，我们可以进一步研究如何将光纤监测技术应用于实际工程中，以提高地面坍塌的预警和监测能力，保护人们的生命财产安全。
Ground collapse events frequently lead to significant economic losses, catastrophic injuries and fatalities. There is a growing need for sensitive monitoring technologies to locate and predict potential ground collapses. This study aims to evaluate the performance of fiber optic (FO) cables for ground collapse monitoring. A model test was conducted in laboratory, and the optical frequency domain reflectometry (OFDR) and particle image velocimetry (PIV) techniques were combined to monitor the whole collapse process. The strain profiles measured by FO cables under different soil failure mechanisms were analyzed in detail. In the case of shallow sinkholes, the soil failure surfaces emanate from the edges of sinkholes and eventually propagate to the ground surface, and the shape of failure surfaces gradually changes from curvy to vertical. Micro-anchors significantly enhance the interface bonding between cables and surrounding soil. Moreover, the settlements calculated based on strain measurements match well with actual settlements.
关键词：Sinkhole, Micro-anchor, Ground collapse, Geotechnical monitoring, Optical frequency domain reflectometry (OFDR)