To identify the contact loss of the interface between sleeper and track slab for twin-block slab track accurately,a finite element model of impact echo for twin-block slab track is firstly established to analyze the in-fluence of interface damage on the propagation law of elastic waves.And concrete composite specimens with dif-ferent damage positions and degrees are poured indoors,and the damage identification is carried out by using im-pact echo method.The results show that contact loss can significantly affect the elastic wave propagation at the interface,and the damage can be identified based on the analysis of the echo signals.The elastic wave frequency is mainly affected by the size of the excitation hammer,and the appropriate hammer should be selected accord-ing to the vulnerable structure position and theoretical calculations.The difference between the experimental thickness and the theoretical thickness of the concrete composite specimen is only 1 cm,which means the test re-sults are reasonable.And it can be used to judge the degree of contact loss,but the damage area cannot be deter-mined.The plane imaging technology can accurately identify the range of interface contact loss between the sleeper and the track slab,which provides a certain reference for the maintenance and repair of the twin-block slab track structures.The test results verify the feasibility and rationality of the impact echo method used in the identification of interlayer contact loss for the twin-block tracks.
关键词
双块式无砟轨道/脱空识别/冲击回波法/模型试验/平面成像
Key words
twin-block slab track/contact loss identification/impact echo method/model test/plane imaging
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