Health monitoring of foundations using fiber Bragg grating sensing technology

Abstract

建筑物地基、基础的现场监测技术一直存在着精度低、稳定性差、不易安装等缺陷。论证光纤光栅传感技术在地基和基础结构健康监测中的应用可行性,并研制光纤光栅应变计、温度计、沉降仪和水平测斜仪等监测仪器,用于监测地基、基础的应变、温度、位移等。室内标定试验结果显示,这些仪器具有分辨率高、稳定性好等优点。在香港某建筑物的施工过程中,在地基和筏式基础中安装了以上的光纤光栅监测仪器,构成准分布式的地基、基础健康监测系统,并实现监测的自动化、远程化。分析初期的监测结果,并针对监测系统实施可能出现的问题提出了解决途径。 Existing techniques for instrumentation of civil structure foundations have limitations, including low accuracy, poor reliability and difficulty in installation. The feasibility of incorporating fiber Bragg grating (FBG) sensing technology into health monitoring of foundation structures is discussed. Innovative FBG strain sensors, temperature sensors, settlement sensors and horizontal inclinometers have been developed to monitor strains, temperatures and displacements in foundations. Results from laboratory calibration tests have shown that these sensors have high resolution and repeatability. These sensors have been successfully installed in the ground and the raft foundation of a building in Hong Kong, with the quasi-distributed foundation monitoring system formed with an automatic and remote configuration. The early-stage monitoring results are obtained and analyzed. Recommendations are proposed to handle the problems that may occur during the instrumentation.