Research On Detective Technology Of Diseases Between The Layers Of Ballastless Tracks In High-speed Railway

Nowadays, despite the widespread application has been carried out in only a few countries, more and more countries began to pave high speed railway, it has become an important trend in the development of the railway. As the comprehensive starts up of the high-speed rail, the increase of the operating range and the growth of the operating time, high speed railways have appeared some problems that calling attention of the people. Many ballastless tracks have appeared some typical diseases such as interlayer hollow, cavity, loose layer, if not found in time, will seriously influence people’s travel safety.Traditional detection method mainly dominated by digging, always damage the roadbed without providing the detailed investigation of long lines, and drilling often wastes time and works, far from meeting the need of current railway overall acceleration and high-speed operation. The GPR(Ground Penetrating Radar, GPR)technology as a new type of detection means, it can combine detecting depth and spatial resolution, realize fast, nondestructive and continuous detection, and display image in real time of the underground environment, very suitable for status investigation and disease detection of ballast bed and roadbed.In order to realize target detection under the surface, by using electromagnetic wave’s reflection and scattering in the discontinuity place of medium electromagnetic characteristics, GPR achieves imaging, positioning and qualitatively or quantitatively identifying the magnetic properties change of the subsurface, is widely used in roadbed disease recognition.Based on GPR, this article conducts the research of testing technology of diseases between the layers of high speed railway ballastless track bed. First, from two directions of both along and perpendicular to the track, respectively conducts modeling and simulation of diseases, to master the features of radar reflection profile from different diseases. Secondly, in the plain concrete environment, change the factors that may affect the imaging effect of the diseases and analysis the variation in the reflection waveform and radar profile toachieve some beneficial conclusions about the diseases between layers of the roadbed, including interlayer hollow, cavity and loose layer. Then, puts the disease to the stratified structure of ballastless roadbed without reinforcement and analyzes the effects on disease reflection characteristics caused by stratified structure,especially the CA mortar layer. Finally, it conducts preprocessing to typical diseases between the layers including both the simulation and actual measured radar signal and enhances the disease characteristic, through studying the reflection principle of each typical disease, to distinguish the imaging characteristics between different attributes of different diseases and gradually realizes the identification of typical disease between the layers from the angle of the instantaneous amplitude,instantaneous phase, instantaneous frequency.