Abstract:
The deformation and failure of the original geological mass can occur under the condition of coal and rock excavation, and the related physical properties (strain field, seepage field, chemical field, temperature field, geophysical field) can change accordingly. To analyze the deformation and failure mechanism in detail, it is necessary to reconstruct and invert the field source characteristics. Therefore, there is an urgent need for a high sensitivity, stable performance and distributed monitoring system for real-time dynamic monitoring of the above field source information. Based on the advantages of optical fiber sensing technology (distributed, high stability, anti electromagnetic interference, etc.), it can make up for the shortcomings of conventional resistance and vibrating wire sensors. This paper points out that it can dynamically monitor the deformation of the surrounding rock in the stope, and the massive data volume obtained can provide support for the recovery and reconstruction of the deformation field and stress field of the surrounding rock. The working principles, advantages, disadvantages and applicable conditions of fiber Bragg grating (FBG), optical time-domain reflectometer (OTDR), Brillouin optical time-domain reflectometer (BOTDR), Brillouin optical time-domain analysis (BOTDA) and Brillouin optical frequency domain analysis (BOFDA) are introduced in detail. The research progress of this technique in deformation and failure of roof and floor, abutment pressure, fault activation monitoring, stability monitoring of coal pillar and stability monitoring of grouting reinforcement of broken rock mass is described. This paper analyzes the existing problems and research hotspots of distributed fiber optic sensing (DFOS) test technology in the current research, and points out the development trend of later research. The main development directions include: (1)Research on the mechanism of rock deformation and instability and mutual feed of optical fiber data volume; (2)Research on coupling performance of optical fiber and rock mass; (3)Data visualization processing and simulation software research; (4)Research on optical fiber monitoring characterization method of rock deformation and failure; (5)Research on applicability of optical fiber for large deformation monitoring in mines; (6)Construction of multi-phase and multi field coupling monitoring system; (7)Construction of monitoring and early warning platform based on multi parameter information fusion of ground and underground integration. The related research is expected to provide reference for the transparent geology of coal mine and intelligent mining.