Research On Anchor Bolting System Based On Magnetostrictive Effect

With the rapid development of China’s economy,China is building a large number of tunnels,railways,highways,water conservancy and hydropower projects.At this time,higher requirements are placed on the support method.Compared with the traditional support methods,the anchor bolt support method has the advantages of low engineering cost and good support effect,so it is widely used in the actual engineering construction.The effect of bolt anchoring support is affected by the environment and construction technology,and even serious quality problems will cause safety accidents,so it is very important to accurately detect and judge the bolt anchoring support.This paper mainly studies the improvement of the detection effect of the array transducer on the bolt anchoring(1)According to the principle of magnetostrictive guided wave detection and the mechanism of electromagnetic ultrasonic transducer,the energy conversion equations between multiple physical fields are established.The MATLAB software is used to solve the relevant equations and draw the guided wave dispersion curve of free anchor,which provides a theoretical basis for the research of electromagnetic ultrasonic guided wave detection technology.(2)By using the numerical simulation and experimental analysis methods,using COMSOL finite element simulation software to establish a three-dimensional free anchor detection model,the offset magnetic field of array transducer and the structural parameters of flexible coil are studied,including the selection of the optimal number of magnetic circuits and lift off distance,the selection of the number of flexible coil clusters and coil layers.Compared with the ordinary sleeve transducer,the array transducer can effectively improve the energy conversion efficiency and defect detection accuracy of the transducer.(3)Aiming at the attenuation of ultrasonic guided wave in anchor detection,the basic detection model of anchor is established by using COMSOL finite element simulation software.The application of array transducer in anchor detection is studied by using numerical simulation method,including the detection of effective length of anchor and the detection of anchor defects.Compared with ordinary sleeve transducer,the detection of array transducer is better It can be used as a measure to improve the amplitude of received signal and the degree of defect identification.(4)The anchor quality testing platform based on array transducer is built.In view of the problems of signal overlap and a large number of noise signals in the experimental results,the frequency modified synchronous compression wavelet transform filtering algorithm is used to reduce noise,and the free anchor with different length,defective anchor and anchorage with different positions are detected,The experimental results are consistent with the simulation results.