Damage Identification Of CRTS ? Type Slab Ballastless Track Based On Dynamic Response Induced By Vehicle Analysis

CRTS ? type slab ballastless track is one of the main structural forms of ballastless tracks in China.After long-term service,track slabs and supporting layer concrete is very likely to crack;CA mortar layer is very possible to disengage.It will greatly facilitate the operation team to develop maintenance plans by identifying the location,range and severity of damage timely.Thus,existing damage's deterioration can be contained effectively.Identifying damage based on the response data of track structure under the excitation of operating vehicle is a simple yet effective method with no interruption of line operation.Therefore,the characteristics of vehicle-induced vibration response of damaged structures are analyzed in this paper.The damage identification method of ballastless track suitable for CRTS ? plate is studied.The main contents are as follows:I.This study focuses on the changing pattern of CRTS ? type slab ballastless track and its dynamic strain response with three types of track structure damage including track slab,supporting layer cracking and CA mortar disengaging.The maximum tensile and compressive strain values in the dynamic strain time history curve are proposed as the damage identification indicators to identify the area and the range of the affected boundary CA mortar demolitions.The damage identification indicators are verified by the damage conditions of CA mortar with different damage lengths.II.Based on the combination of wavelet packet energy spectrum and K-L divergence,the acceleration frequency domain differential quantization analysis is proposed.The re-distribution level of the vehicle vibration acceleration frequency of the track plate and the supporting layer of the CRTS ? type slab ballastless track after the occurrence of various types of damagedamage types is analyzed,The damage factor of the energy spectrum K-L divergence is constructed based on above analyses.Based on the coefficient of AR model and the concept of Euclidean distance,the time-domain statistical characteristics of the acceleration of CRTS ? type slab ballastless track are analyzed.According to this,the AR model damage factor is put forward.The variation of acceleration signal correlation indices between CRTS ? type slab track and supporting layer after damage is studied.According to this,the regression coefficient,mutual energy index and the mean value of vibration transfer rate are proposed as damage indexes to identify the damage of CRTS ? type slab ballastless track.the damage identification indicators are verified by the damage conditions of CA mortar with different damage conditions.III.Based on support vector machine's classification algorithm and regression algorithm in theory,it fulfils the identification of the influence range of CA mortar void,the location of crack damage of track slab and supporting layer,and the recognition of the degree of crack damage.