A fibre Bragg grating based inclinometer system for ground movement measurement

摘要

The measurement of ground movement is an essential part of many geotechnicalengineering operations. For decades, inclinometer systems have traditionallybeen used for this purpose to provide crucial information to engineers andresearchers. However, conventional inclinometer systems have their limitations,such as high cost and poor durability. In this paper a fibre optic basedinclinometer system is reported, which utilizes fibre Bragg grating sensorsattached to the casing of a conventional inclinometer. The characterization ofthe sensor revealed good agreement with theory and conventional displacementmeasurements. For a casing of length 2.5 m, the minimum measureable deflectionof the top of the casing was found to be 0.48 mm when the FBGs were interrogatedwith a 1 pm wavelength resolution system.