对纵向导波在水泥砂浆锚固锚杆中的传播特性进行了分析.根据弹性动力学理论,首先建立了三维柱坐标的水泥砂浆锚固锚杆中纵向导波的频散方程,并数值求解了纵向导波的相速度、能量速度和衰减频散曲线,由频散曲线可知,500 kHz范围内水泥砂浆锚固锚杆中存在5个纵向导波模态;然后分析了特定频率下,纵向导波在水泥砂浆锚固锚杆横截面的位移分布,结果表明:锚杆截面上轴向位移越大,代表纵向导波对锚杆体的周向缺陷越敏感,而锚杆与水泥砂浆接触面上的径向位移越大,则表示从锚杆泄漏至水泥砂浆中的纵向导波能量越大;最后讨论了锚杆尺寸和水泥砂浆材料属性的变化对纵向导波的能量速度和衰减频散曲线的影响.为实现水泥砂浆锚杆锚固质量纵向导波的无损检测提供了理论基础.
The propagation properties of longitudinal guided wave in cement mortar anchored bolts are studied in this article. Based on the elastodynamic theory, the longitudinal guided wave dispersion equations are established in three dimensional cylindrical coordinate, and the corresponding phase velocity, energy velocity and attenuation dispersion curves are obtained. It can be observed from the dispersion curves that five longitudinal guided wave modes exist in the bolt under the frequency 500 kHz. The displacement distribution of guided wave with certain frequencies is analysed. Results show that guided waves with large axial displacement distribution are sensititive to circumference defects on the bolt while guided waves with large radial displacement distribution in the bolt/cement mortar interface cause great energy leakage; Finally, the effects of bolt size and properties of cement mortar on longitudinal guided wave energy velocity and attenuation dispersion curves are discussed. And the theoretical basis for nondestructive testing of cement mortar anchored bolts using longitudinal guided waves is stated in the article.