Optical Grating Monitoring and Measuring System of Stress Variation for Backfilled Mass in Goaf of Gateway Retained and Application

According to the high measuring range stress monitoring and measuring conducted on the backfilled mass during the support process of the gateway ret ained along goaf, high measuring range optical fiber and optical grating sensor and fiber on-line monitoring and measuring system was designed based on optical fiber and optical grating.The monitoring and measuring system was consisted with the mine optical fiber and optical grating demodulator, communication optical cable and ot hers.The double optical grating temperature compensation method was applied to effectively reduce the low temperature drift affected to the monitoring and measuring accuracy.The monitoring and measuring system was applied to the real time on-line monitoring and measuring on the stress variation conditions of the lined wall in the gateway retained along goaf of No.3203 coal mining face in Dongtan Mine.The results showed that the high measuring range optical fiber and optical grating sensor an d the optical fiber on-line monitoring and measuring system could real time and accurately monitor and measure the stress variation process during the support process of the gateway retained along goaf and could provide the basis to further optimize the support structure and to determine the support plan of the gateway retained along the goaf.