Coaxial waveguide-based geotechnical multi-point deformation sensor and method of adjustable gauge-length measurement

Abstract

A coaxial waveguide-based geotechnical multi-point deformation sensor and an adjustable gauge-length measurement method are provided. The coaxial waveguide-based geotechnical multi-point deformation sensor includes an outer conductor, open at opposite ends and hollow inside; magnetic metal support frames, inside the outer conductor, sequentially spaced along an axial direction of the outer conductor and each having a through-hole; an inner conductor inside the outer conductor and passing through each through-hole; and annular magnets, surrounding the outer conductor and configured to move along it, driving the nearest magnetic metal support frame to follow its movement. Each magnetic metal support frame acts as a reflection point. By reconstructing the interference spectra of any two reflection points, a gauge-length can exist between any two of the magnetic metal support frames. By collecting the changes in the interference spectrum signals of different gauge-lengths, deformation of geotechnical layers corresponding to the gauge-length(s) can be calculated, thus allowing the deformation of any geotechnical layer to be determined.