College of Safety Science and Engineering, Liaoning Technical University, Huludao, Liaoning, China.
Key Laboratory of Mine Thermodynamic Disasters and Control of Ministry of Education, Liaoning Technical University, Huludao, Liaoning, China.
PLoS One. 2022 Apr 28;17(4):e0267099. doi: 10.1371/journal.pone.0267099. eCollection 2022.
To monitor the safety status of the bolts in coal mining roadways in real time, the safety and stability of the bolt support structure were evaluated. Based on the conventional support bolts used in the field, a fiber Bragg grating (FBG) sensor and medium materials were selected. Through theoretical analysis, the bolt tension, and FBG temperature tests, the strain transmission mechanism of the FBG bolt was analyzed, and it was ensured that the developed FBG bolt could accurately measure the strain of the bolt. In the field test, FBG bolts were arranged on the positive and negative sides of the mining roadway to accurately monitor the safety status of the bolts in service in real time, and the force characteristics of the bolts monitored by the FBG sensor were analyzed to obtain the maximum axial force of the positive and negative bolts. Thereafter, the safety status of the roadway bolt was evaluated. The results show that the positive side bolts axial force change is significantly greater than that of the negative side bolt; with the working face advancing to a distance of 60 m from the bolt as the dividing line, the positive side bolts axial force grows slowly before this, after which the axial force increases rapidly. The locations of the roadway where the positive and negative bolts are most affected by mining are determined, and roadway support and prevention measures for this location should be conducted in time. The safety status of the bolts is evaluated and monitored as follows: the positive side No. 2, No. 3, No. 5, and No. 6 bolts have reached the failure state, the positive side No. 4 bolt is in a dangerous state, the positive side No. 1, negative side No. 8 and No. 9 are in an abnormal state, and the negative side No. 7, No. 10, No. 11, and No. 12 are in a normal condition. This research has laid a technical foundation for the real-time monitoring of the bolt support of the mining roadway and the assessment of the safety status of bolts.
为实时监测煤矿巷道中锚杆的安全状态，评估锚杆支护结构的安全稳定性。基于现场使用的常规支护锚杆，选择了光纤布拉格光栅（FBG）传感器和中介质材料。通过理论分析、锚杆拉力和 FBG 温度测试，分析了 FBG 锚杆的应变传递机制，确保所研制的 FBG 锚杆能够准确测量锚杆的应变。在现场试验中，在采动巷道的正、负两侧布置 FBG 锚杆，实时准确监测锚杆在役安全状态，分析 FBG 传感器监测到的锚杆受力特征，得到正、负锚杆的最大轴向力。进而对巷道锚杆的安全状态进行评价。结果表明，正侧锚杆轴向力变化明显大于负侧锚杆；以距锚杆 60m 为工作面推进分界线，在此之前正侧锚杆轴向力缓慢增长，之后轴向力迅速增加。确定了正、负侧锚杆受采动影响最大的巷道位置，并应及时对该位置进行巷道支护和防治措施。对锚杆的安全状态进行评价和监测如下：正侧 2、3、5、6 号锚杆已达到失效状态，正侧 4 号锚杆处于危险状态，正侧 1、负侧 8、9 号锚杆处于异常状态，负侧 7、10、11、12 号锚杆处于正常状态。本研究为煤矿巷道锚杆支护的实时监测和锚杆安全状态评估奠定了技术基础。
