Research on stress analysis and application of rockbolt anchoring based on optical fiber monitoring

Taking the 310 roadway of Longtan Coal Mine as the engineering background,the stress change of rockbolt support under the monitoring method of optical fiber sensing technology was studied. Firstly,according to the theoretical analysis of the interface strain transfer between the optical fiber and the rockbolt,the average value of the strain transfer coefficient was 0. 879,which was used to demodulate the optical fiber monitoring data. Secondly,the pull-out test of optical fiber anchor rockbolt under different pressure of surrounding rock was designed,and BOTDA was used to monitor the strain of the optical fiber rockbolt during the solidification process of the anchoring agent and the pull-out test. The monitoring results show that the optical fiber can accurately monitor the small strain and the strain change rate, and then analyze the strain characterization of different pressure of surrounding rock and pull-out forces on the rockbolt length. Finally,the test results were applied to the engineering site. The results show that the optical fiber sensor can better identify the abnormal data in the rockbolt support during the monitoring period. The research results provide new ideas and methods for optimizing the monitoring system of roadway rockbolt support under deep mining environment.