注浆锚杆完整性检测方法研究

Research on method for detecting integrity of grouted rock bolts

采用理论分析和实验室测试的方法对锚固锚杆和自由锚杆中的导波传播规律进行了研究,并在频率为20 kHz～3 MHz范围内对锚固锚杆和自由锚杆波的传播速度进行了测试,发现锚固锚杆内不同频率的导波传播速度对锚固介质具有不同的敏感性。低频率段(20～200 kHz)的导波传播速度对锚杆锚固质量较为敏感,自由锚杆和锚固锚杆中导波的传播速度相差较大,适合于检测锚杆的锚固质量。高频率段(1～3 MHz)的导波传播速度对锚杆锚固质量不敏感,导波的传播速度基本不变,适合于锚杆完整性检测。探索了利用高频段多频率导波检测锚固锚杆长度的方法。实验室检测结果显示,本检测方法具有很高的精度。

The law of guided wave propagation in grouted and free rock bolts is studied by theoretic analysis and laboratory testing method.The wave propagation velocity in grouted rock bolt and free bolt within 20 kHz-3 MHz is tested in laboratory respectively.The and research shows that the different frequencies have different sensitivities to grout quality.Low frequency（20 kHz-200 kHz） guided wave changes its velocity greatly with grout quality;and high frequency（1-3 MHz） doesn’t change.So low frequency（20 kHz-200 kHz） which has high sensitivity to grout quality can be used to test grout quality and high frequency（1-3 MHz） whose velocity doesn’t change with grout quality can be used to test integrity of rock bolt.The laboratory test results show that the method has very good accuracy;and a method for testing grouted length of rock bolt is proposed.