树脂锚杆锚固质量超声导波检测技术
Ultrasonic Guided Wave Inspection Technique in Anchorage Quality of Steel Bolt Embedded in Epoxy Base
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摘要: 研究了锚杆锚固质量超声导波检测技术。根据理论得到的频散曲线, 选取适合树脂锚杆锚固质量检测的高阶纵向模态和激励频率。试验中, 直径22 mm, 长2 800 mm的锚杆埋置于长度不断增加的环氧树脂层中, 采用脉冲回波法在锚杆结构中接收不同锚固长度时高阶纵向模态的第一次端面回波。试验结果表明, 随着树脂握裹长度的增加, 高阶纵向模态的第一次端面回波峰峰值呈近似线性下降趋势。Abstract: Ultrasonic guided wave inspection technique in anchorage quality of steel bolt embedded in epoxy was investigated experimentally. According to dispersion curves derived from theoretical prediction, high-order longitudinal guided wave modes which were suitable for anchorage quality inspection of steel bolt embedded in epoxy and their excitation frequencies were chosen. In the experiments, a 22 mm diameter and 2 800 mm length steel bolt was embedded in epoxy layer with gradually increasing length. Based on pulse echo method, first end-reflected signals of high-order longitudinal guided wave modes were received in the anchorage structure under the condition of gradually increasing length of epoxy layer. Experimental results showed that there was an approximate linear decrease of the peak-to-peak amplitudes of received first end-reflected waves of high-order longitudinal guided wave modes with the increase of embedded length of the bolt.