Abstract: Aiming at the existing problems of low efficiency,lagging monitoring results,poor reliability and accuracy in present roadway roof separation monitor,a new highprecision FBG separation indicator was designed through theoretical analysis,laboratory test and field test according to the fiber grating sensing principle.On this basis,a realtime online roof separation monitoring system was proposed.The calibration and performance test results of roof separator indicator suggested that it has good linearity sensitivity and high sensitivity.The linear fitting coefficient is 0.998 3 respectively.The sensitivity coefficient is 1.6 pm/mm.The minimum separation variation of about 0.63 mm can be monitored.The monitoring system was successfully applied to roof separation monitoring of the14301 # track roadway in Shaqu Coalmine.The monitoring results showed that the online roof separation monitoring system based on the highprecision FBG separation indicator has the advantages of high precision,good stability and longdistance signal transmission,which can achieve realtime dynamic monitoring and provides an effective method for longterm online monitoring of roadway roof separation.

Key words: fiber grating sensing,FBG roof separation indicator,roadway roof separation,online monitoring system