The Internal Damage Detection Of Ballastless Track Concrete Structure Based On The Gaussian Curvature And Impact Echo

The ballastless track has become the main type of track structure of high-speed railway in our country because of the characteristics of the high smoothness, high stability and less maintenance. Along with the massive construction of high-speed railway in our country, the ballastless track has developed rapidly and applied widely. However, the ballastless track Act the foundation of the high-speed train running. The structure always exposure to the complex atmospheric environment all the year round. Under the ordeal of water, temperature gradient and train load, at the same time with the construction quality and technical defects give rise to the damages of ballastless track. However, the damages of ballastless track have threated seriously the security Operations of high-speed railway and the service life of rail equipment. In order to detect, the damage and the damage location accurately, it is of utmost urgency to research the method of ballastless track damage detection.Firstly, Summarizing ballastless track structural style and functional characteristics in our country. Basing on the locale research of the ballastless track damages. Category summarized the type of damages and the causes of damage. In this article, Combining with the ballastless track own characteristics. Through summarizing and studying the research achievements in the concrete structure damage identification. Comparising and screening the whole and local detection method of concrete construction.Finally, Combing the whole and local detection method to detect the ballastless track damage.For the research of whole detection method, Researching the ballastless track damages based on the finite element method, mode theory and Gaussian curvature. The results show that:When there is no damage of ballastless track, the track slab gaussian curvature surface of each order modal is smooth and continuous.At the same time, there is no obvious peak. When there are a single or several damages of ballastless track and CA motor,The results of gaussian curvature will mutate in the damage location. The curvature mutation indicate that the rigidity mutated in the damage location. Finally, make a further judgment on the base of the rigidity mutation.However, the gaussian curvature result can qualitate judge the damage, but it can not quantitate the damage.For the research of local detection method, The impact echo method can identify the depth of damage by the stress wave reflection on the different wave impedance interface theory.Firstly, researching the optimum distance between excitation and response point,the result show that the appropriate distance is 0.04m. Secondly, Using the acceleration response values to identify damage depth. Finally,researching the stress wave propagation rules in the ballastless track structure. The impact echo method determine the depth of different damages accurately in the ballastless track by the analysis of frequency domain.The whole and local damage identification method can identify the different damages of ballastless track by theoretical simulation calculation. In order to test the effectiveness of detection in practical engineering.Making ballastless track modal with different size damage to test by modal and impact echo method. Results of the trial indicated that the combination of the two methods can not only determine whether there is a wound, but also can locate damage space.