Rock three-way pressure stress sensor based on optical fiber grating sensing

Abstract

The invention discloses a rock three-way pressure stress sensor based on optical fiber grating sensing. The rock three-way pressure stress sensor comprises a cubic box body, wherein the box body is provided with six surfaces; three of the six surfaces which share a vertex are stress surfaces; each of the other three surfaces which share the vertex is provided with a recessed disc and serves as a recessed disc surface; fastening screw holes which have the same size and are uniformly distributed are formed at the periphery of each recessed disc; an optical fiber channel is formed in the center of each recessed disc; a sensing film is connected to each recessed disc; a small circular thin plate in the middle of each sensing film is an effective pressure bearing surface, and an optical fiber grating is adhered to an inner surface of the small circular thin plate; a sensing film supporting end is arranged at the periphery of the effective pressure bearing surface; screw holes which have the same size and are uniformly distributed are formed at the periphery of the supporting end; a box body penetration hole is formed at each vertex of the stress surfaces and the recessed disc surfaces;and the optical fiber channels are connected with two box body penetration holes. The rock three-way pressure stress sensor is intrinsically safe, free from electromagnetic interference, high in long-term stability, large in range, high in accuracy, high in sealing performance, pressure-resistant, corrosion-resistant and the like.

Description

technical field [0001] The invention relates to the field of geotechnical engineering monitoring, and more particularly relates to a geotechnical three-dimensional compressive stress sensor based on optical fiber grating sensing, which can be used for stress testing of rock and soil bodies, and is especially suitable for stress testing of soft rock and soil. Background technique [0002] Most of the existing compressive stress sensors in the field of civil engineering monitoring can only measure the pressure in one direction. Chinese patents 03212896.7, 200810246302.1, and 201120082368.9 disclose several compressive stress sensors, each with its own characteristics. However, after comprehensive comparison and analysis, the existing compressive stress sensors mainly have the following problems: 1) The sensing principle of the existing compressive stress sensors is mostly based on the steel string type, the test accuracy of this type of sensor is not high enough, and the long-t...

AI Technical Summary

Problems solved by technology

However, after comprehensive comparison and analysis, the existing compressive stress sensors mainly have the following problems: 1) The sensing principle of the existing compressive stress sensors is mostly based on the steel string type, the test accuracy of this type of sensor is not high enough, and the long-term stability of the sensor Not good enough, easy to drift, susceptible to electromagnetic interference; or based on resistance strain gauge type, this type of sensor has relatively high accuracy, but is susceptible to electromagnetic interference, the range is not large enough, and the long-term stability is not good enough; 2) Existing pressure stress sensors Most of them can only measure the pressure in one direction, and cannot measure the pressure in three directions at the same time; 3) Most of the existing pressure stress sensors are based on electrical signals or electrical related signals, which are not intrinsically safe and cannot be used in rich It is used in harsh environments such as underground coal mines with gas; 4) It is difficult for existing pressure stress sensors to monitor pressure for a long time and in real time

[0004] In summary, the existing geotechnical stress testing methods and devices are not effective in engineering practice, and it is necessary to invent new geotechnical compressive stress testing devices and methods

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