Study On Fiber Bragg Grating Monitoring Of Stratum Subsidence In The West Airshaft Of Dongtan Coal Mine

Dongtan coal mine nearby Baodian and Xinglongzhuang coal mine which belongs toYanzhou mining area, appeared wall crack repeatedly, but to this days, Shaft lining has beennot rupturing in Dongtan coal mine. However, observation shows that vertical additional stressof wall in the west airshaft increased with the mining intensity and range year by year,decreased of water level in the Quaternary aquifer, made the wall deformation increases. Themonitoring of the FBG sensors system prediction method of wall deformation, which cansatisfy the requirements of mine remote, distribution and long-term technology, and realize theon-line transmission and real-time analysis.In this paper, according to the basic principle of fiber Bragg grating sensor, analyzed theeffect of borehole embedded fiber Bragg grating strain transform theory and the modulus ofelasticity and poisson’s ratio of the middle layer cement mortar on the average StrainTransform Coefficient. By the theoretical of unconsolidated strata dehydration subsidencecalculation model, established the strata deformation and surface subsidence. Studied theoptimal west airshaft strata subsidence monitoring system scheme in Dongtan coal mine byfiber Bragg grating, and with the aid of3G wireless transmission, achieves data sharing over along distance. Through strata subsidence of fiber Bragg grating monitoring strain transferparameter experiments and the west airshaft strata subsidence with optical fiber Bragg gratingcorresponding relationship of simulation, the grating monitoring hole sealing is obtained withthe best ratio of cement mortar, ground subsidence and the amount of fiber Bragg grating driftlinear relationship; Concluded that the ratio of the hole sealing mortar mechanical parameters,and calculated the various sealing hole section of the fiber Bragg grating strain transfer rate,provide strong conditions for site construction and data analysis.Based on theoretical research, the successful completion of the west airshaft fiber Bragg grating monitoring stratum settlement system installation, and the monitoring data during theinstallation and the later is analyzed, the monitoring system of fiber Bragg grating by firstgrouting effect is obvious, the system stability after the part of the central wavelength down tothe initial state. At the same time, monitoring system of fiber Bragg grating also has achievedmonitoring the mine pumping, and the water injection test, relieves the unconsolidatedformation dehydration subsidence status. Based on long-term monitoring data, preliminarilypredicted the deformation of the west airshaft wall.