Effects of frequency and grouted length on the behavior of guided ultrasonic waves in rock bolts
Effects of frequency and grouted length on the behavior of guided ultrasonic waves in rock bolts
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DOI：
10.1016/j.ijrmms.2006.12.002
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发表时间：
2007-09
影响因子：
7.2
通讯作者：
D. Zou;Y. Cui;V. Madenga;Chuanda Zhang
中科院分区：
文献类型：
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作者：
D. Zou;Y. Cui;V. Madenga;Chuanda Zhang
进行实验来研究导波在自由和灌浆岩石锚杆中的行为。使用频率为 25 至 100kHz 的超声波作为激励输入。首先对自由螺栓进行测试，以帮助了解非灌浆螺栓中导波的行为。然后评估波频率和灌浆长度对引导超声波的群速度和衰减的影响。测试结果表明，自由螺栓和灌浆螺栓的群速度有明显但不同的趋势。自由螺栓的衰减不受螺栓长度和频率的影响。然而，在灌浆螺栓中，它随着频率和灌浆长度的增加而增加。研究还发现，衰减的两个主要来源是设置能量损失，对于特定类型的测试设置，其具有固定的量，以及随频率和螺栓长度变化的色散和传播能量损失。
Experiments were conducted to study the behavior of guided waves in free and grouted rock bolts. Ultrasonic waves with frequencies from 25 to 100kHz were used as excitation inputs. Tests were first conducted on free bolts to help understand the behavior of guided waves in non-grouted bolts. The effects of wave frequency and grouted length on the group velocity and attenuation of the guided ultrasonic waves were then evaluated. The test results indicated clear but different trends for the group velocity in the free and the grouted bolts. The attenuation in free bolts was not affected by bolt length and frequency. However, in grouted bolts it increased with frequency and grouted length. It was also found that the two main sources of attenuation are the setup energy loss, which has a fixed quantity for a specific type of test setup, and the dispersive and spreading energy loss which varies with frequency and bolt length.