| By the end of 2021,the operating mileage of high-speed railways in China will exceed 40 thousand kilometers.High-speed railways generally adopt ballastless track structures,which have the characteristics of high integrity,high smoothness,high stability,and less maintenance.At present,the section track quality index TQI and the over-limit peak value,these two evaluation methods are mainly used to evaluate the track status.Since the TQI index of the ballastless track is transformed from the line index of the ballasted track,in the course of many years of use,it is found that the irregularity amplitude of the ballastless track is small,the structural deterioration has the characteristics of time,and the maintenance mode is adjusted by fasteners.Inapplicability in the case of local maintenance,especially the‘disrepair’or‘over-repair’brought about by the track quality status evaluation under the minor change,Safety risk and maintenance cost have become important issues in the maintenance of ballastless track.The specific research work and results are as follows:（1）Using the dynamic detection data of high-speed railway tracks in China,the track geometric quality index（TQI）with the standard deviation of track irregularity as the index,and the track irregularity index with the number of track irregularity amplitude exceeding the limit as the index（P value）,and the section track roughness index（R~2）with the track irregularity deviation as the index and other three types of evaluation index systems are compared and analyzed,and the problems existing in the application of the existing evaluation indexes in the high-speed railway ballastless track lines in China are pointed out combined with the typical roughness of high-speed railway ballastless track,put forward the optimization direction of incorporating the standard deviation of 70m wavelength irregularity and the square root of track roughness index into the existing TQI evaluation index system.（2）Using a large amount of historical detection data of high-speed railway ballastless track lines,analyze the statistical law and characteristics of track irregularities in sections,the statistical characteristics of typical irregularities of ballastless tracks,and the evaluation indicators of ballastless track degradation and the relationship between the length of the unit section and so on,and put forward a suggestion that the optimal unit length for ballastless track geometric quality evaluation and maintenance mode should not exceed 200m.（3）Based on the repair regulation,the evaluation index for maintenance of ballastless track（TMEI）and the recommended index for maintenance of ballastless track（TMRI）suitable for ballastless track lines are proposed,which integrate the conversion of static and dynamic management values.The two indicators respectively take the static operation acceptance and regular maintenance management values in the repair regulations as the design threshold,and take the sum of the amplitude exceeding the threshold and the interval area of the sampling points as the calculation method to evaluate the track geometric quality status and identify the sections that need to be repaired in time.（4）In order to make up for the deficiency that TQI cannot evaluate the state change of track section,based on the time-varying characteristics of ballastless track structure,a ballastless track section degradation evaluation index（TSDI）is proposed,which can be used to compare and analyze the degradation law of ballastless track line under the real-time data based on the line pull through test data.On this basis,in order to compare the evaluation of fine adjustment effect of different lines,a one-year deterioration evaluation index is proposed to evaluate the deterioration degree of section track and the maintenance and renovation effect of different lines. |
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