基于光纤监测的锚杆锚固应力分析与应用研究
Research on stress analysis and application of rockbolt anchoring based on optical fiber monitoring
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摘要: 以龙滩煤矿310巷道为工程背景,引入光纤传感技术作为监测手段,研究锚杆支护的应力变化。首先,根据光纤与锚杆间的界面应变传递理论分析得出应变传递系数平均值为0.879,并用于解调光纤监测数据;然后,设计不同围岩压力下的光纤锚杆拉拔试验,利用BOTDA监测光纤锚杆在锚固剂凝固过程中及拉拔试验中的应变,监测结果显示光纤能够精准监测到微小应变及应变变化速率,进而分析不同围岩压力与拉拔力在锚杆长度上的应变表征显现;最后,将试验成果应用于工程现场,结果表明光纤传感器在监测周期内能够更好地识别锚杆支护中的异常数据。研究成果可为深部开采环境下巷道锚杆支护监测体系优化提供新思路与新方法。Abstract: 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.