The Development And Application Of Testing Instrument Of Bolt Anchorage Based On Chirp Signal

With our country increase the infrastructure investment after the reform and opening up, all kinds of large geotechnical project are constantly emerging, and anchor technology is widely used. However, the construction of anchor belong to hidden project, and construction quality is affected by geological conditions and construction technology, there often exist indistinguishable trouble, resulting in engineering accidents and great economic losses. So it is necessary to detect the construction quality of anchor bolt, and to ensure the project safety.At present, there are many methods have been used to anchor construction quality detection, and the stress wave nondestructive testing method is the most widely used. Compare with other testing method, stress wave nondestructive testing is nondestructive, rapid, real-time and can comprehensively reflect the anchor construction quality, etc. However this method there are also many problems, such as bolt bottom and defect position reflection is often difficult to identify and mortar density is inaccurate in the test process, etc. In view of the above questions, this paper put forward the improved method from two aspects:(1) vibroseis technology is introduced into the research and development of anchor quality testing equipment, effective information extraction of detection signal can be improved because source signal is known;(2) found a suitable signal processing methods, improve the judgment accuracy of anchor bottom and anchorage defect position reflection point.In the research of vibroseis, first of all, this paper lay the foundation for the development of vibroseis by introducing the giant magnetostrictive effect and the design principle of giant magnetostrictive source. In the second, this paper analyses several common source signals and compare themselves with each other. And found that Chirp signal, which has a wide frequency band, good self-correlation, strong penetrating power and antijamming capability etc., is very suitable to serve as anchor test source signal. Finally, realized the application of vibroseis, which be successfully developed by using the giant magnetostrictive material and Chirp signal as the source signal, in the field of anchorage quality test. Compared with the traditional hammer and piezoelectric ceramic source, the giant magnetostrictive source excitation waveform stable, the detection requirements is low, and is helpful to the testing data of the subsequent analysis.In signal processing, in order to try to find a suitable signal processing method for bolt testing field and improve the quality of anchor rod anchor detection accuracy and reliability, this paper put forward the Wigner-Ville distribution and Hilbert transform applied to bolt anchorage quality testing signal processing, and use these methods for large bolt model testing analysis. Then we successfully developed a set of anchor rod anchor quality analysis software using the Delphi software development platform, in order to facilitate its application and promotion.Based on the above, this paper apply wireless transmission technology to research and development of anchor quality testing equipment, and use the laptop computer and the United States NI company production based on Wi-Fi wireless transmission technology of dynamic data acquisition equipment WLS-9234data acquisition card successfully developed a set of anchor quality testing instrument. This equipment, which is simple operation and easy to carry, can adapt to all kinds of complicated testing environment and improve the detection efficiency of the staff.In the last place, the instrument and software is applied to test a lot of model anchor bolt and field test anchor bolt. The results show that the instrument improves the quality of anchor rod anchor the detection accuracy and can be a very good meet the engineering requirements. But due to the bolt anchorage system is a complicated system and stress wave nondestructive testing theory research is still not perfect, the overall precision of this method is not high and the anchor workers need to remains further research.