Field test and numerical analysis of rail frozen joint in turnout area of heavy haul railway

A joint with strong displacement limiting effect is required at the connection between turnout and main lines in heavy haul railway. Frozen joints can solve this problem, but the existence of the joint destroys the continuity of the rail, resulting in greater dynamic impact load between wheel and rail. The track structure is prone to damage under the long-term wheel-rail interaction. First, through a large number of field tests, the irregularity characteristics of joints were analyzed. Second, the typical damaged joints were selected for the train dynamic tests, and the wheel-rail impact was measured on site. Finally, a three-dimensional (3D) coupling model of train-rail joint was established by finite element method, and the maintenance standard of the joint was studied. The results show that the frozen joints often appear concave irregularity near rail gap during long-term service. The dynamic test of the concave joint shows that there is an obvious height difference distribution in the vertical direction of the rail displacement on both sides of the rail gap, and the rail displacement on the towards wheel side is greater than that on the along-wheel side. When the wheel passes through the concave joint, it is easy to produce a towards-wheel height difference impact mode. From the dynamic bending stress of the plate, the wheel has two large impact when passing through the each side of the gap, and the impact is greater when passing through the gap; By analyzing the dynamic force of heavy-haul wheels passing through the joint, it is concluded that the maximum concave depth of frozen joint at the operation site should be controlled within 0.5 mm. The results can provide some reference for revealing the field service status of frozen joints and the maintenance measures. © 2023, Central South University Press. All rights reserved.