The Detection Methods And Research About Full-wavefild Imaging Detection Method On High Speed Railway Under-track Structure

In recent years, the construction of high-speed railway is gradually increased. It is ready to rush out of Asia toward the word. However, more and more defects appeared with the increasing growth of operating time and the operating mileage. Such as transverse crack, interlayer segregation and so on. So how to detect the disease quickly and accurately will be solved in the current civil engineering issues. A new nondestructive testing method is carried out-full-wave field imaging detection system. It is based on the characteristics of high speed railway structure and the existing level of disease. It is a new non-destructive testing method based on the latest developments in research and development about electronic technology, computing and image processing technology. The analysis methods and detection accuracy are very different from the traditional method of elastic waves.Firstly, it is the investigation and analysis about the defects of high speed railway under-track structure. Then the 3-D FEM models are established. The analysis of propagation mechanism and thin-film interference in layered media are carried out based on the three-dimensional elastic wave equation. In particular, the impact of fluctuations in the internal structure by medium parameters, as well as its impact on the projected surface of the medium. It contains the amplitude of elastic wave and spectrum amplitude. When there is a week layer of dielectric multilayer internal structure, the results shows that strong reflection appears on the upper part of week layer and energy attenuation on the lower part of the weak layer. Its surface projection showed increases in response to the energy and amplify excellent characteristics. Then analysis the geometric analysis of wave field boundary effects and surface properties affect the response. At last evaluate the impact of the range of geometric borders.Based on the results of finite element simulation, a full-wave field of non-destructive testing method is carried out. Then build the full-wave field of non-destructive testing systems. The system integrates the point-source/point-receiver scheme with the multi-directional imaging technique. It is equipped with an impacting hammer, a series of three-component velocity transducers and a signal capturing unit. Then record the size and direction of the media surface wave field. Through complex mathematical analysis, including in response to energy analysis method and excellent spectral characteristics, constructed from three-dimensional image data field fluctuations and physical properties of the internal structure of the distribution media. Details introduced the data collection, data analysis and defect evaluation.In order to verify the full wave field NDT methods in high-speed railway line construction disease detection effectiveness. An experimental of 1:1 scale of high-speed railway model is carried out. Collect the full-wave field data by point to point method. After the analysis of waveform, it shows a good consistence between the result and the defects in the design position. At last, the full-wave field detection is carried out in real high speed railway under-track structure. A fast full-wave field detection method is designed to fit the actual situation.The experimental study is supported by National Science Foundation : Research field full wave propagation characteristics and associated non-destructive testing methods in geotechnical engineering complex medium(11372180) and a major issue China Railway Corporation Technology Research and Development Program: Disease Mechanism of high-speed railway line engineering and rapid detection Recognition Technology-Structural Hazard nondestructive testing techniques under study multilayer high-speed rail line(2013G004-A-1).