基于同轴电缆布拉格传感器的分布式地表形变观测方法研究

Observations of surface deformation are essential for understanding a wide range of geophysical problems, including earthquakes, volcanoes, landslides, and glaciers. As for current geodetic technologies, such as GPS, InSAR, borehole or laser strainmeters, there is a blank area in the continuous observation of medium-long scale (several kilometers). This application plans to apply the mature technologies of the distributed fiber Bragg grating (FBG) to the coaxial cable Bragg grating (CCBG) by using the similarity principle, and to study the large surface deformation's accurate measurement with high temporal and spatial resolutions by distributed CCBGs. While, with the positive feedback system and the suppression transmission attenuation design, the coverage of the distributed CCBGs will be extended to several kilometers. And to remove the environmental noise, the coupling phenomenon of temperature and strain will be relieved by the dual CCBGs design. The application tends to fill in the medium-long scale’s surface deformation observation area between the large scale (such as InSAR) and the small scale (such as GPS and borehole or laser strainmeter), and to cover the last several kilometers of the surface deformation observations, which will provide a new way for the study of geophysical structures such as faults, volcanoes, landslides, and glaciers, as well as inhomogeneous activities of their transition zones.

地表形变观测是研究地震、火山、滑坡，以及冰川活动等一系列地球物理学问题的重要研究手段。然而现有的地表形变观测手段如GPS、InSAR、钻孔应变仪等，在中长尺度（公里级）的连续观测上存在空区。本项目拟运用相似原理，将较为成熟的分布式光纤光栅应变测量技术应用于同轴电缆布拉格传感器，研究大应变量的高精度、高时-空分辨率、高准确度的测量方法；同时借助正反馈系统与抑制传输衰减设计，将分布式同轴电缆布拉格传感器的覆盖范围拓展到公里量级；依靠双路同轴电缆布拉格传感器设计解除温度与应变的耦合现象，去除环境干扰。本项目的意义在于填补大尺度（如InSAR）与小尺度（如GPS、钻孔应变仪等单点观测手段）之间中长尺度的地表形变观测空区，解决地表形变观测最后几公里的问题，为研究断层、火山、滑坡，以及冰川等地球物理构造及其过渡带的不均匀活动提供一条崭新的途径。

地表形变观测是研究地震、火山、滑坡，以及冰川活动等一系列地球物理学问题的重要研究手段。然而现有的地表形变观测手段如GPS、InSAR、钻孔应变仪等，在中长尺度（公里级）的连续观测上存在空区。本项目运用相似原理，将较为成熟的分布式光纤光栅应变测量技术应用于同轴电缆布拉格传感器，研究了一种新型的地表形变观测方法。运用HFSS仿真软件建立了CCBG传感器模型，借助正反馈系统与衰减抑制等技术手段设计并试制了地表形变测量系统样机，并进行了性能验证试验。本项目的意义在于填补大尺度（如InSAR）与小尺度（如GPS、钻孔应变仪等单点观测手段）之间中长尺度的地表形变观测空区，解决地表形变观测最后几公里的问题，为研究断层、火山、滑坡，以及冰川等地球物理构造及其过渡带的不均匀活动提供一条崭新的途径。