Study on the splashing behavior of high-speed railway ballast in ice and snow environment: Analysis of the influence of the train speed, ice mass and striking position

Abstract

The snow flight in severe cold regions has occurred on many high-speed railway lines in China, directly impacting the safety of high-speed railway operations. However, the research on this problem has not been carried out systematically at present, and the establishment of the theoretical simulation model remains blank. In this paper, the DEM-MBD-CFD coupling analysis method is used to build a refined simulation model of snow flight on high-speed train-ballasted track, which reproduces the actual scenes of three typical cases where the snow flight hits the train body and verifies the reliability of the model with field test results. The results show that the wind pressure amplitude at the center of the ballast bed is the largest, the bottom of the rail is the second largest, and the shoulder of the ballast is the smallest. After the ballast particles fly away from the ballast bed, the main power source is the negative pressure generated by the train’s airflow field. The number of flying ballast particles and the impact force on the train floor grow with the increase of train speed. When the train speed increases to 400 km/h, the average impact force increases to 12.76 kN, which is approximately 8.7 times the impact force at 250 km/h. With the increase of ice mass, the impact stress first increases rapidly and then slowly. When the ice mass is 7 kg, the impact stress has exceeded the yield strength of the train body, seriously affecting the safety of the operation. Many prevention measures, such as reducing the operation speed, implementing ice and snow removal, installing anti-splash coating and grille, and optimizing the structure design, can be taken to reduce the damage of snow flight.