Research On Void Damage Identification Of Ballastless Track Based On Vibration Responce

The voiding of CA mortar layer is one of the most common damages in the ballastless track of high-speed railway.There are many kinds of damage diagnosis methods available,but the methods that can really adapt to complex track structures are very scarce.Therefore,it is of great significance to establish a special identification technology for ballastless track structure void damage on the basis of existing testing and processing technology.In this paper,the dynamic model of track structure with different degree of void damage is established.Based on the vibration response data of different parts of the structure,the damage identification of track structure void is studied by means of various data analysis and signal processing methods.The main conclusions obtained are as follows:(1)Through the comprehensive comparison and analysis of the advantages and disadvantages of the existing damage identification technology at home and abroad,and combined with the characteristics and identification requirements of ballastless track structure void damage,the method of combining feature index extraction and pattern recognition technology is determined to carry out the research on the identification of track structure void damage.(2)Using dynamic finite element software,six analytical models with different degrees of damage were established.And using statistical analysis theory and signal processing technology to analyze the vibration response data of different measuring points.Firstly,vibration response data are processed separately in time domain,frequency domain and time-frequency domain to extract highly sensitive characteristic indicators which can synthetically characterize the degree of damage.The results show that 11 feature indices are extracted in time domain,8 feature indices are extracted in frequency domain and 10 feature indices are extracted in time-frequency domain.(3)In order to fully reflect the structural characteristics of ballastless track and the transmission characteristics of impact loads between different parts of the structure under damaged conditions,four damage characteristics are further excavated and extracted through vibration transmission characteristics and correlation analysis.(4)Based on the 33 highly sensitive damage characteristics extracted above,the pattern recognition method of principal component analysis is used to identify the degree of ballastless track void damage.The validity and correctness of the method to identify the void damage of track structure are verified by experiments.In the practical application of future engineering,the damage degree of track structure can be effectively identified by combining the measured data after processing with the above damage characteristic indexes and using principal component analysis.