煤矿锚杆轴向受力无损检测试验研究与应用

Experimental study and application on non-destructive testing of bolt axial force in coal mine

煤矿巷道锚杆轴向受力是衡量其工作状态的重要指标,现有的检测手段尚不能有效对锚杆轴力状态进行随机、快速的无损检测。基于结构动力学原理,建立了锚杆轴向受力与锚固系统横向固有频率间的关系,并借助于专用的电液伺服锚杆拉力试验系统,测定了锚杆直径、锚固状态、围岩条件对锚固系统横向振动频率、锚杆轴向受力的影响规律。结果表明:锚杆锚固系统的横向振动频率与锚杆轴向受力具有很好的相关性;围岩性质是影响系统横向振动频率的主要因素之一;锚杆锚固系统的振动频率与锚杆轴向受力间可用对数函数关系描述。开发了锚杆轴向受力的无损检测技术,现场应用结果证明了该项技术对巷道锚杆轴向受力实施随机、无损检测的可行性。

Bolt axial force is an important indicator of its working state in coal mine tunnel. The cur- rent detection means can not able to carry out random, rapid, non-destructive testing technology. In this paper, the relationship between horizontal natural frequency of anchoring system and bolt axial force has been established based on the principles of structural dynamics. By means of the dedicated elec- tro-hydraulic servo system of bolt tensile testing, the influence of bolt diameter, anchoring state and surrounding rock conditions on the lateral vibration frequency of anchoring system and bolt axial force has been measured. The results show that the lateral vibration frequency of bolt anchoring system and bolt axial force have a good correlation, and the surrounding rock condition is one of the main factors affecting the lateral vibration frequency. The relationship between lateral vibration frequency and bolt axial force can be described by logarithmic function. Base on research founds, the nondestructive testing technology of bolt axial force has been developed. The field application shows that the technology can randomly, non-destructively detect the axial force of bolt in the tunnel.