Abstract: In order to detest the stress distribution of the anchor bolts, a fiber Bragg grating(FBG) optical fiber sensing technology was adopted to build a long-term bolting quality online monitoring system.. The rock bolting process and forces existing in a coal mine tunnel are simulated in the laboratory and the bolt pullout test has been conducted. By fiber Bragger grating the strains of the anchor bolt are measured. Then the strain dates are fitted with Gauss function. The axial stress distribution and the shear stress distribution are got. The experiment results show that it is feasible to test strain of the anchor bolt by FBG. The axial stress can be fitted accurately by Gauss function. The parameter t of the Gaussian function is related to the grip ability of the rock. The shift in changing direction of parameter t indicates that the interface between the rock and the bolt is changing and the grip ability of the rock begins declining. The research result can be a reference for the real-time monitoring of anchor bolt quality.

Key words: stress distribution, shear stress distribution, fiber grating, Gauss function