Control threshold of pier settlement in high-speed railways based on train vibrations

For the safety and smoothness of running trains in the pier settlement area of high-speed railways, a method to investigate the control threshold of pier settlement in high-speed railways was proposed based on the train-track-bridge dynamic interaction theory. The limit values of pier settlement in existing standards were discussed, and the key factors affecting the control threshold of pier settlement were determined. In view of the nonlinear factors including the track random irregularity and wheel-rail nonlinear contact relationship, a high-speed train-track-bridge coupled dynamics model considering the pier settlement and multi-factor was built based on the train-track-bridge dynamic interaction theory. On this basis, the influence of pier settlement on the train-track-bridge system under the multi-factor influence was studied, and the control threshold of pier settlement for high-speed railways in China was proposed to ensure the safety and smoothness of the running train. Research results show that the factors including the track random irregularity, temperature action, and concrete shrinkage and creep cannot be ignored in studying the control threshold of pier settlement in high-speed railways. As the bridge span is broader, the concrete shrinkage and creep and temperature action cause the increases in the carbody vertical acceleration and wheel unloading rate, while the pier settlement leads to the decrease in the above indicators. The carbody acceleration and wheel unloading rate considering the multi-factor are significantly higher than those without considering the multi-factor. As the pier settlement is larger, the carbody vertical accelerations and wheel unloading rates exceed the limit values when the train runs through different irregularity samples. The control threshold of pier settlement for high-speed railways is suggested to be 10 mm to guarantee the running safety and ride comfort of the running train. Based on the control threshold obtained in this paper, the accurate standard limit value can be obtained by further considering other factors, such as construction errors. The research results can provide a method and data supporting for the final determination of the limit value of pier settlement. © 2022, Editorial Department of Journal of Traffic and Transportation Engineering. All right reserved.