Coal-rock interface stability measuring device with fiber grating composite structure

Abstract

The invention relates to a coal-rock interface stability measuring device with a fiber grating composite structure. The coal-rock interface stability measuring device comprises an axial pressure gauge, an anchor rod, fiber grating strain sensors, fiber grating strain gauges, an external optical cable protective shell, an optical cable, a photoelectric detector and a fiber grating demodulator, wherein the axial pressure gauge comprises a pressure elastic sheet, the fiber grating strain gauges and a pressure transfer column; when the pressure elastic sheet receives axial pressure, the pressure is transferred to the fiber grating strain gauges through the pressure transfer column by the pressure elastic sheet; four fiber grating strain gauges connected in series are connected to a first optical fiber channel of the anchor rod in series. Four optical fibers are arranged around the anchor rod, each optical fiber is connected to seven fiber grating strain sensors to sense surrounding strain,the four optical fibers and the external optical cable are connected in the external optical cable protective shell through flanges, a pressure signal is input into the fiber grating demodulator through the optical cable and the photoelectric detector for demodulation, so that the coal-rock interface stability is monitored in real time.

Description

technical field [0001] The invention relates to the technical field of fiber grating sensing, in particular to a coal-rock interface stability measuring device with a fiber grating composite structure. Background technique [0002] Fiber grating is essentially a passive filter formed by periodically modulating the refractive index of the fiber core. Fiber Bragg grating has the following advantages: strong anti-electromagnetic interference ability, the fiber will not be disturbed by electromagnetic waves during transmission; small size, fiber Bragg grating is compatible with optical fiber; long transmission distance, high precision, fiber Bragg grating measurement accuracy is not affected by light intensity , has the characteristics of easy networking measurement and integration, so it has been widely used in the field of optical fiber communication and sensing. [0003] As an important part of my country's energy production and supply system strategy, coal resources have ma...

AI Technical Summary

Problems solved by technology

[0004] Anchor bolts are widely used in geotechnical engineering fields such as coal roadway support, slope reinforcement, tunnel support, etc., and their force monitoring is of great significance for improving construction technology and optimizing design parameters. However, due to the distribution of geological Complicated, there are problems such as cross-sensitivity of axial stress and surrounding stress

Images