A fiber grating type six-direction pressure sensor for stress measurement in deep soft rock

Abstract

The invention discloses a fiber grating type six-way pressure sensor for deep soft rock stress measurement, including a solid sphere provided with six pressure sensing unit mounting slots and a cylindrical optical fiber slot. A fiber grating pressure sensing unit is mounted in the pressure sensing unit mounting slots. Optical fibers connected with the fiber grating pressure sensing unit are converged in the cylindrical optical fiber slot along optical fiber wiring slots arranged in the outer surface of the solid sphere. A spherical shell covering the solid sphere from the outside is provided with a cylindrical outlet hole at a position corresponding to the position of the cylindrical optical fiber slot and is provided with cylindrical mounting holes at the positions corresponding to the positions of the pressure sensing unit mounting slots. The pressure sensor is applicable to deep soft rock geostress measurement. Based on the working characteristics of optical signal transmission, the pressure sensor has the advantages of satisfying the essential safety requirements of deep coal mine stress monitoring, is not affected by electromagnetic interference, has good long-term stability, and can realize real-time monitoring of the rock stress state.

Description

technical field [0001] The invention belongs to the field of geostress measurement, and in particular relates to a fiber grating type six-direction pressure sensor for deep soft rock stress measurement. Background technique [0002] Obtaining accurate ground stress measurement data is an important prerequisite for determining the mechanical properties of engineering rock mass, analyzing the stability of surrounding rock, and realizing scientific excavation design and decision-making in geotechnical engineering. Currently commonly used geostress measurement methods, such as hydraulic fracturing and stress relief methods, are generally applicable to intact hard rocks, and the test success rate is very low when encountering deep broken and weak rock masses. [0003] The rheological stress recovery method is a new method of in-situ stress measurement specially proposed for deep broken and weak surrounding rocks. This method utilizes the strong rheological behavior of deep broken...

AI Technical Summary

Problems solved by technology

At present, the pressure sensors commonly used in geotechnical engineering are mostly used for earth pressure measurement, and their measurement range is small, and they are unidirectional pressure measurements, which are difficult to meet the multi-directional and large-range requirements of the ground stress test of the flow stress recovery method.

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