布里渊光频域分析技术(Brillouin Optical Frequency Domain Analysis,BOFDA)是全分布式光纤感测技术中的一种,具有独特的测试与监测优势.将BOFDA应用于海上超长PHC(Prestressed High Strength Concrete)管桩内力测试,并在超长PHC管桩...布里渊光频域分析技术(Brillouin Optical Frequency Domain Analysis,BOFDA)是全分布式光纤感测技术中的一种,具有独特的测试与监测优势.将BOFDA应用于海上超长PHC(Prestressed High Strength Concrete)管桩内力测试,并在超长PHC管桩成桩过程中,就将传感光缆植入桩身中,可明显提高传感光缆的成活率和测试精度.现场测桩试验结果表明:在超长PHC管桩成桩过程中传感光缆的植入工艺是十分成功的,桩身轴力和侧摩阻力测试结果能够很好地反映桩身内力的分布变化规律,成效显著,为PHC管桩,特别是海上超长PHC管桩的内力测试提供了一种新的内力测试方法,值得推广.展开更多
近年来,布里渊频域分析技术(Brillouin Optical Frequency Domain Analyzer, BOFDA)已被成功地应用到岩土体、地质及建(构)筑物结构的温度和应变监测中。介绍了BOFDA技术的原理,设计了管道模型的环向收敛变形模型试验,并将BOFDA技术成...近年来,布里渊频域分析技术(Brillouin Optical Frequency Domain Analyzer, BOFDA)已被成功地应用到岩土体、地质及建(构)筑物结构的温度和应变监测中。介绍了BOFDA技术的原理,设计了管道模型的环向收敛变形模型试验,并将BOFDA技术成功应用到管道的环向收敛变形监测中。通过设计不同的感测光缆的布设工艺,对比不同的传感元件和布设工艺之间的性能差异。实验获取了不同围压下管道的收敛变形值以及管道的环向应变,建立了同比例Finite Element Modeling(FEM)模型,模拟各实验情况下管道的各项性能指标,并将数值计算结果与实测结果相对比。对比分析表明,基于BOFDA技术的分布式光纤传感器测得管道外表面为压应变,内表面为拉应变,其监测数值及规律与FEM模拟分析结果表现一致。据此得出:BOFDA技术可有效地应用于管道的环向收敛变形监测,可定性的定位管道应力集中位置及定量的获取应力应变数值。实际工程中,该技术可在管道及隧道的受力变形监测领域推广应用。展开更多
High-sensitivity monitoring solutions are crucial for early warning systems of earth structures. In this paper, we discuss the design and implementation of such systems for natural and engineered slopes using two case...High-sensitivity monitoring solutions are crucial for early warning systems of earth structures. In this paper, we discuss the design and implementation of such systems for natural and engineered slopes using two case studies. At the Gradenbach Observatory, one key element of the monitoring system is a large fiber optic strain rosette embedded in the slope. We demonstrate that the strain rosette can depict landslide deformations much earlier than geodetic sensors like GPS or total stations and is therefore well suitable for an early warning system. In a second application we report the construction of a reinforced earth structure using geogrids. A distributed fiber optic measurement system was installed to measure the current operating grade of the geogrids within the earth structure. About 2 km of Brillouin sensing cables were installed in the project area. It is demonstrated that the developed monitoring system is well suited for assessing the current state of health of reinforced earth structures.展开更多
文摘布里渊光频域分析技术(Brillouin Optical Frequency Domain Analysis,BOFDA)是全分布式光纤感测技术中的一种,具有独特的测试与监测优势.将BOFDA应用于海上超长PHC(Prestressed High Strength Concrete)管桩内力测试,并在超长PHC管桩成桩过程中,就将传感光缆植入桩身中,可明显提高传感光缆的成活率和测试精度.现场测桩试验结果表明:在超长PHC管桩成桩过程中传感光缆的植入工艺是十分成功的,桩身轴力和侧摩阻力测试结果能够很好地反映桩身内力的分布变化规律,成效显著,为PHC管桩,特别是海上超长PHC管桩的内力测试提供了一种新的内力测试方法,值得推广.
文摘近年来,布里渊频域分析技术(Brillouin Optical Frequency Domain Analyzer, BOFDA)已被成功地应用到岩土体、地质及建(构)筑物结构的温度和应变监测中。介绍了BOFDA技术的原理,设计了管道模型的环向收敛变形模型试验,并将BOFDA技术成功应用到管道的环向收敛变形监测中。通过设计不同的感测光缆的布设工艺,对比不同的传感元件和布设工艺之间的性能差异。实验获取了不同围压下管道的收敛变形值以及管道的环向应变,建立了同比例Finite Element Modeling(FEM)模型,模拟各实验情况下管道的各项性能指标,并将数值计算结果与实测结果相对比。对比分析表明,基于BOFDA技术的分布式光纤传感器测得管道外表面为压应变,内表面为拉应变,其监测数值及规律与FEM模拟分析结果表现一致。据此得出:BOFDA技术可有效地应用于管道的环向收敛变形监测,可定性的定位管道应力集中位置及定量的获取应力应变数值。实际工程中,该技术可在管道及隧道的受力变形监测领域推广应用。
文摘开展围护结构和支撑体系的监测对于控制基坑开挖变形、保证结构安全具有十分重要的意义。传统传感器监测多为点式测量,其自动化程度低、测量值与实际值误差大、难以发挥传感器工程预警的作用。基于布里渊散射光频域分析技术(Brillion Optical Frequency Domain Analysis,BOFDA)的光纤传感器具有空间分辨率高、精度高、信噪比高的优势。通过在4根原有传统钢筋计支撑上布设分布式光纤传感器,文章对布里渊散射光频域分析技术(BOFDA)与传统监测手段进行了对比,分析了支撑体系全断面受力特性,探讨了分布式光纤感测技术在基坑工程监测中的优势。研究结果表明:分布式光纤传感器可反映不同开挖工况下支撑轴力变化规律以及支撑通长方向轴力的不均匀性,实现支撑体系的全断面受力分析以及基坑开挖过程的安全预警。
基金the Austrian Academy of Sciences(OeAW)for funding the landslide monitoring project for several yearsthe Austrian Federal Railways(OBB)for the funding of the geogrid monitoring project,especially the participating departments of OBB-Infrastruktur AG:Tunneling,Surveying and Data Management,Research and Development
文摘High-sensitivity monitoring solutions are crucial for early warning systems of earth structures. In this paper, we discuss the design and implementation of such systems for natural and engineered slopes using two case studies. At the Gradenbach Observatory, one key element of the monitoring system is a large fiber optic strain rosette embedded in the slope. We demonstrate that the strain rosette can depict landslide deformations much earlier than geodetic sensors like GPS or total stations and is therefore well suitable for an early warning system. In a second application we report the construction of a reinforced earth structure using geogrids. A distributed fiber optic measurement system was installed to measure the current operating grade of the geogrids within the earth structure. About 2 km of Brillouin sensing cables were installed in the project area. It is demonstrated that the developed monitoring system is well suited for assessing the current state of health of reinforced earth structures.