Study On Measure Parameters For Vibration Testing Based On Partially Grouted Metal Bolt

Some characteristic quantity parameters such as valid bonding length, consolidation wave speed, have been proved that these parameters can qualitative reflect the bolt bonding quality. For anchor system quantitative assessment, the dynamic parameterized testing is studied in this paper.In order to accurately simulate complex field anchoring condition, first, a variety of anchor test factors is decomposed, then single factor of the system is tested respectively. According to the design condition and factors ascending, complex loading level test is carried on in the next three aspects:(1) The accelerometer installation and incentive methods are done in the condition of single free rock bolt;(2) The connection between bolt plate and rock bolt, the installation and incentive methods;(3) The different restriction and tension style.Base on the free rock bolt test and the factors ascending way, the best accelerometer installation and optimum excitation wave is gotten. Some complex load levels work is done:(1) Fix the bolt and set the level tensile load, then the dynamic response curves is obtained respectively on every condition from one end is fixed and one end is free to design tension values.(2) Using the same tension method above to test the response curves after the bolt is anchorage in pre-simulated"stable rock";(3) On account of non-axial tension working condition, shear-stretch and flexural-tensile experiment is also implemented respectively by fixed and anchorage.The second, based on the one-dimensional stress wave propagation in the rod, vertical vibration at three boundary conditions and vibration characteristics under the excitation force for one end is fixed end the other is free, vibration characteristics is calculated by the tension end. Via the calculate, we will know relationship between resonant frequency and energy, and the first frequency have occupied more than 80%, all of which will provided a foundation to analysis the low frequency signal.For the third, on the foundation of energy attenuation, reflectance at the interface of media, attenuation energy loss analytic is established, fixed end reflection for one wave cycle scattering attenuation is calculated, then the size of control volume dynamic effects of regional is got, and we can easy to assure the model size and definite some theoretical foundation for site evaluation.Fourth, utilize wavelet analysis and the length method of fractal dimension, effective signal position and the entire cycle are both extracted. In free rock bolt signal-to-noise ratio is relatively high; time-domain waveform calculation of attenuation can be done directly, on the contrary, wavelet denoising, appropriate wavelet is used to analysis the signal, then the approximation signal in time domain and useful approximation signal and detail signal spectrum is got. After that, the average time single wave cycle and tension anchorage section attenuation coefficient which can more accurately reflect the anchorage, has been got by the length method of fractal dimension and attenuation coefficient calculation which is based on the approximation signal. At last, three new methods, attenuation coefficient, single wave cycle and frequency spectrum, is got which can reflect the anchorage.