In August 16, 2011, it was found in the pilot section that there were many cracks in the projectile strip, and a special inspection was organized on the whole line. The number of cumulative damage strips was found to be 558 (456 cracks and 102 cracks).
The Bureau further analyzed the inspection results and found that:
According to the analysis of the longitudinal section, 74 of the sections of the damaged area were 14.4%, 85.6% in the lower slope, no damage in the vertical curve section, and no injury in the 100m range before and after the slope point. It is preliminarily concluded that the distribution of damage is not related to vertical curve and variable slope point, and the probability of downhill section distribution is larger.
According to the track structure analysis, there are 484 II slab sections on the bridge, accounting for 94.2%, 30 of the II type slab on the roadbed, 5.8%, and the ratio of two to 16.2:1. The ratio of the length of the II plate laying length bridge section to the road base section in the Ji'nan bureau is 2.7:1. The preliminary conclusion is that the damage of the elastic strip occurs in the bridge section and the base section, but the damage probability in the bridge section is 6 times that of the subgrade.
According to the analysis of the damaged parts of the bullet strip, the injured parts were located in the middle of the hind legs of the VOSSLOH300-1A type elastic stripe, which initially showed ring cracks and later vertical fractures. Preliminary conclusion: the central point of the rear part of the elastic bar is the stress concentration point, which is the weakest part of the elastic strip.
According to the analysis of the distribution characteristics of the damage damage in the track, the damage zone of the bullet bar is relatively concentrated, the injury damage in the section of the bullet strip appears continuously, and it is concentrated on a rail. If it can not be found and replaced in time, it is very easy to cause the rail to lose the restraint and fall to one side, leading to the derailment accident.
According to the analysis of the light belt in the rail surface of the damaged bullet strip, it is found that the band of the light band is abnormal, the band has a periodic wide narrow change, the wavelength is about 140mm, the band is the narrowest 15mm and the width 32mm is most wide, and there is a transverse grinding scratch on the R300 of the rail top surface at the narrowest spot of the band. 1~5, the distance between grinding and scratching is the same as that of light band. The preliminary conclusion is that the distribution of damage is closely related to the periodic grinding and scratching on the rail surface.
According to the above situation, the damage of the bullet strip occurs mainly in the abnormal light band. The abnormal light belt is closely related to the periodic scratches left by the rail grinding car. Therefore, it is the best solution to ease the problem of the bullet damage in Beijing-Shanghai high-speed railway, by regrinding the rail, rationally determining the grinding way, optimizing the selection and collocation of the grinding wheel of the grinding wheel and eliminating the periodic scratches about 140mm on the rail surface.