Coal mine tunnel roof stress online monitoring system based on fiber grating sensor and method thereof

Abstract

The invention provides a coal mine tunnel roof stress online monitoring system based on a fiber grating sensor and a method thereof, and is suitable for the field of tunnel mine pressure monitoring. The coal mine tunnel roof stress online monitoring system based on the fiber grating sensor comprises monitoring and observation stations which are arranged on the roof of the tunnel of the two sides of a coal face. Each monitoring and observation station comprises three roof stress monitoring devices. The roof stress monitoring devices in each monitoring and observation station are connected in series together through communication optical fibers. The tail fiber of the lead-out end optical fiber of the monitoring and observation station of each tunnel tail end is connected with an optical fiber terminal box through the communication optical fiber. The optical fiber terminal box is connected with a fiber grating static demodulator arranged on the ground through a transmission optical cable for mining. The fiber grating static demodulator is connected with a monitoring computer and a network server in turn. The network server is connected with multiple client sides through a coal mine local area network. The coal mine tunnel roof stress online monitoring system is high in measurement accuracy and long in the service life so as to realize real-time online monitoring of the coal mine tunnel roof stress.

Description

technical field [0001] The invention relates to a monitoring system and method, in particular to an online monitoring system and method for coal mine roadway roof stress based on an optical fiber grating sensor, which are suitable for the field of roadway mine pressure monitoring. Background technique [0002] With the continuous increase of coal mining depth in our country, the stress changes of roadway roofs and gob roofs have become more and more complex. In the past ten years, thousands of roof accidents have occurred in domestic coal mines, accounting for nearly half of the total number of coal mine accidents. Therefore Real-time monitoring of roof stress changes in coal mine roadway, judging the stability of the roof, and taking effective protective measures in time have great practical significance for preventing frequent roof accidents. [0003] The sensing principle of the original fiber grating force-measuring anchor is that the force-measuring anchor is stretched ...

AI Technical Summary

Problems solved by technology

[0003] The sensing principle of the original fiber grating force-measuring anchor is that the force-measuring anchor is stretched and strained together with the grating attached to it. The maximum elongation of the force-measuring anchor is 17%, while the maximum elongation of the fiber grating is 0.3%. Once the strain of the force-measuring anchor is greater than 0.3%, not only the purpose of force measurement cannot be achieved, but also the fiber grating will be damaged. Even if some desensitization measures such as springs are adopted, it is still difficult to solve this problem in the actual installation process

[0004] Existing FBG load-measuring anchor rods: the defect that the FBG strain and the anchor rod strain are not easy to coordinate within the effective range, that is, the anchor rod strain is too large compared to the FBG, causing the FBG to be broken or the measurement results to be inaccurate. precise

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