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| Properties of torsional guided wave propagating in grouting bolts |
| Received:June 26, 2014 Revised:September 12, 2014 |
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| DOI：10.7511/jslx201505012 |
| KeyWord:grouting bolt grouting media torsional guided wave energy velocity attenuation dispersion |
| Author | Institution |
| 何文 |
江西理工大学 资源与环境工程学院, 赣州 ;江西理工大学 江西省矿业工程重点实验室, 赣州 |
| 赵奎 |
江西理工大学 资源与环境工程学院, 赣州 ;江西理工大学 江西省矿业工程重点实验室, 赣州 |
| 宁建国 |
北京理工大学 爆炸科学与技术国家重点实验室, 北京 |
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| Abstract: |
| The propagation characteristics of torsional guided waves in grouting bolts were theoretically studies.Firstly,dispersion equations of torsional guided wave propagation in two-layer structure of grouting bolts were established,then energy velocity and attenuation dispersion curves were calculated and displacement distribution characteristics of guided waves were obtained.Results show that:(1) In the frequency range of 500 kHz,only three torsional guided wave modes exist in grouting bolts,which are T(0,1)、T(0,2) and T(0,3),and the three guided wave modes are dispersive.As frequency increases.guided wave energy velocity increases as well,and the attenuation value of guided wave decreases.(2) T(0,1) guided wave mode with frequencies of 50 kHz and 200 kHz maintains large circumferential displacement inside the bolt,which means that the guided wave mode is suitable for bolt flaw testing.Meanwhile the guided wave mode maintains large circumferential displacement in the bolt/grout interface,which leads to guided wave energy leakage from bolt into grout media,and guided wave attenuates significantly.(3) When guided wave frequency is higher than 100 kHz,the varying of bolt diameter has almost no effect on T(0,1) mode guided wave energy velocity,At the meantime,when guided wave frequency is lower than 100 kHz,T(0,1) mode guided wave energy velocity decreases as the increasing of grout media'elastic modulus. |
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