煤矿锚杆轴力检测时锚固系统振动特性参数分析  

The analysis of vibration frequency parameter of rock bolt anchorage system during axial force testing in coal mine

作　　者：郝阳 吴宇[1,2] 张凯 李盼[3] 孟庆彬 HAO Yang;WU Yu;ZHANG Kai;LI Pan;MENG Qingbin(State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;School of Mechanics and Optoelectronics Physics,Anhui University of Science and technology,Huainan,Anhui 232001,China)

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116 [2]中国矿业大学力学与土木工程学院,江苏徐州221116 [3]安徽理工大学力学与光电物理学院,安徽淮南232001

出　　处：《采矿与安全工程学报》2022年第3期567-575,共9页Journal of Mining & Safety Engineering

基　　金：中央高校基本科研业务费项目(2021-11112)。

摘　　要：基于锚固系统振动特性的锚杆轴力动力无损检测技术在理论、试验及应用方面取得了一定进展,然而,现场应用中存在频谱曲线不够平整光滑、特征点难以识别的问题,给轴力分析造成困难,其关键原因在于影响锚固系统振动特性的参数尚不明确。基于此,首先分析轴力、锚固段黏结刚度、托盘与围岩接触刚度与锚固系统一阶固有振动频率的关系,得到以上参数对频谱曲线的影响;然后分析不同激振方式下锚杆的振动特性,得到最优激振方式,提出现场锚杆轴力无损检测流程;最后在现场进行工业性试验,验证参数分析后的轴力与一阶固有频率的关系。锚固系统一阶固有频率随轴力增大变化最敏感,无损检测轴力分析中应当建立其与一阶固有频率之间的关系;一阶固有频率取值范围在0~2 000 Hz;树脂黏结等效刚度、托盘等效弹簧刚度与一阶固有频率表现为非线性正相关,随着树脂黏结等效刚度、托盘等效弹簧刚度的大小不断增大,系统的一阶固有频率逐渐表现为对数关系。振动最优激振选取为2 000 g带硬塑料头的刚性小锤进行激振,能够激发出法向激振力为20~25 N的振动,此时频谱曲线较为光滑平整,易于识别。现场锚杆轴力动力无损检测结果表明,锚杆实时轴力与一阶固有频率可以用对数关系来表达。Based on vibration characteristics of rock bolt anchorage system, the dynamic non-destructive testing(NDT) technology of axial force has been advanced in theory, experiment and field application. However, the spectrum curve obtained in field application sometimes was not smooth enough and characteristic points were difficult to identify, which caused difficulty for the analysis of axial force. The key reason is that parameters affecting vibration characteristics are still unclear. Therefore, in this paper, firstly, the relationship among axial force, bonding stiffness of anchoring, contact stiffness of plate, and surrounding rock with the vibration frequency of anchoring system was analyzed, and the influence of above-mentioned parameters on spectrum curve was obtained. Secondly, vibration characteristics by different excitation were analyzed, the optimal excitation method was obtained, and the optimization process of NDT was proposed. Finally, field application was carried out on the excavation face to verify the optimization process of NDT. The results have shown that first-order natural frequency of anchoring system increases most sensitively with the increase of axial force, the relationship between axial force and first-order natural frequency should be established in the analysis of non-destructive testing axial force;the value range of first-order natural frequency is 0-2 000 Hz;the relationship between bonding equivalent stiffness and the equivalent spring stiffness with the first-order natural frequency show a positive non-linear correlation. The best excitation is experimentally selected by a rigid hammer with a mass of 2 000 g and a hard-plastic head, which can excite a vibration with a normal striking force of 20 to 25 N. The spectrum curve is relatively smooth and flat, easy to recognize. The results of non-destructive testing of the on-site bolt axial force have shown that real-time axial force of the bolt and first-order natural frequency can be expressed in a logarithmic relationship.

关 键 词：锚杆轴力 无损检测 频谱分析 一阶固有频率 参数分析 

分 类 号：TD82[矿业工程—煤矿开采]