基于POF-OTDR的混凝土坝裂缝定量监测及POF布设研究

Study of quantitative crack monitoring and POF layout of concrete dam based on POF-OTDR

塑料光纤由于弥补了石英光纤易发生断裂的不足,且具有大纤径、良好韧性、高可塑性、低成本等优良特性,在结构健康监测领域具有广阔的应用前景.为了利用塑料光纤实现对混凝土坝裂缝的定位、定宽和定向监测,本文结合理论分析和模型试验研究了基于塑料光纤-光时域反射技术(POF-OTDR)的裂缝定量监测方法.首先通过大量试验建立了裂缝的定量监测模型,在分析裂缝监测的可能构型的基础上提出了双支塑料光纤的裂缝定量监测方法,并通过试验加以验证,然后以此为基础提出了塑料光纤混凝土坝裂缝监测基本网络构型.最后,以某混凝土拱坝为例结合数值计算研究了塑料光纤裂缝监测网络布设.

It is widely accepted that plastic optical fibers will have broad application prospect in the field of structural health monitoring because the fiber is not easy to break like silica optical fibers and it also has excellent characteristics such as large diameter,good toughness,high plasticity and low cost.In order to monitor the location,width and direction of cracks in concrete dam,quantitative crack monitoring method of concrete dam based on POF-OTDR is studied theoretically and experimentally.Firstly,mathmatical model of quantitative crack monitoring is established through a lot of model tests.Then double-POF crack monitoring method is presented and validated experimentally after analysing possible layout methods.Based on this interpretation,a reasonable POF network layout scheme for crack monitoring is proposed.Finally,network structure for a concrete arch dam is discussed based on numerical calculation.