布里渊光频域分析技术(Brillouin Optical Frequency Domain Analysis,BOFDA)是近年来在国际上研发成功的一种分布式光纤传感技术,该技术已经开始被广泛应用于结构体和工业设备等的温度和应变感测,而最新的分布式应变测试技术可达到20c...布里渊光频域分析技术(Brillouin Optical Frequency Domain Analysis,BOFDA)是近年来在国际上研发成功的一种分布式光纤传感技术,该技术已经开始被广泛应用于结构体和工业设备等的温度和应变感测,而最新的分布式应变测试技术可达到20cm的空间分辨率和±2με的应变测试精度。文中首先介绍了BOFDA的工作原理以及技术验证,然后将该技术应用到钻孔灌注桩的桩身应变测量中,得到了桩身轴力及侧摩阻力的变化规律,并与钢筋应力计测得的桩身轴力数据做了对比,结果表明,BOFDA测试结果准确,可作为一种新型的桩基测试技术加以推广。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
报道了一种基于双向拉曼放大的布里渊光时域分析系统(Brillouin optical time domain analyzer,BOTDA).利用双向拉曼抽运对信号光进行拉曼放大以补偿光纤损耗及布里渊抽运波的消耗,从而使光纤后端的测量分辨率得到改善,测量分辨率在整...报道了一种基于双向拉曼放大的布里渊光时域分析系统(Brillouin optical time domain analyzer,BOTDA).利用双向拉曼抽运对信号光进行拉曼放大以补偿光纤损耗及布里渊抽运波的消耗,从而使光纤后端的测量分辨率得到改善,测量分辨率在整段传感光纤趋于一致,同时避免了调制不稳定性引起的频谱扩展,克服了传统BOTDA存在的信号强度指数下降的弊端,使传感精度得到进一步提高.实验实现了50km传感距离,温度分辨率达0.6℃,空间分辨率为50m.实验测量并分析了基于双向拉曼放大的BOTDA信噪比和光功率分布特性.展开更多
文摘布里渊光频域分析技术(Brillouin Optical Frequency Domain Analysis,BOFDA)是近年来在国际上研发成功的一种分布式光纤传感技术,该技术已经开始被广泛应用于结构体和工业设备等的温度和应变感测,而最新的分布式应变测试技术可达到20cm的空间分辨率和±2με的应变测试精度。文中首先介绍了BOFDA的工作原理以及技术验证,然后将该技术应用到钻孔灌注桩的桩身应变测量中,得到了桩身轴力及侧摩阻力的变化规律,并与钢筋应力计测得的桩身轴力数据做了对比,结果表明,BOFDA测试结果准确,可作为一种新型的桩基测试技术加以推广。
基金The Key Project of Jiangxi Electric Power Company(No.200950801,No.200950802)the National High-Tech Research and Development Programs(No.2009AA01z255)+4 种基金the Program for New Century Excellent Talentsin University(No.NCET-06-0094)111 Project(No.B07005)the Fundamental Research Funds for the Central Universities(BUPT2009RC0406)Beijing New Star Program of Science and Technologies(No.2007A048)BUPT Project(Key Tech.WDM-PON)
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.
文摘报道了一种基于双向拉曼放大的布里渊光时域分析系统(Brillouin optical time domain analyzer,BOTDA).利用双向拉曼抽运对信号光进行拉曼放大以补偿光纤损耗及布里渊抽运波的消耗,从而使光纤后端的测量分辨率得到改善,测量分辨率在整段传感光纤趋于一致,同时避免了调制不稳定性引起的频谱扩展,克服了传统BOTDA存在的信号强度指数下降的弊端,使传感精度得到进一步提高.实验实现了50km传感距离,温度分辨率达0.6℃,空间分辨率为50m.实验测量并分析了基于双向拉曼放大的BOTDA信噪比和光功率分布特性.
