Mechanical Properties of Rock Ballast in Combined Tamping and Stabilizing Operations Using Numerical Dynamic Domain

The maintenance effort for a ballast bed is determined by the combination of tamping and stabilizing, which have always been separated in previous researches. In this study, a tamping-stabilizing-ballasted track was established, and a dynamic domain was innovatively developed to improve calculation efficiency. This model was verified through a comparison with field test results. Using this model, the mechanical properties of ballast bed in tamping and stabilizing under different combination modes were firstly analyzed. The results indicate that the mechanical characteristics of rock ballast in tamping are much more intense than those in stabilizing, and repeated tamping may aggravate ballast degradation, but is beneficial for ballast rotation. Repeated tamping and stabilizing operations are conducive to the coordination number of rock ballast and contact density on the sleeper but have opposite effects on the compactness of rock ballast and pressure on the sleeper. The optimal combination model is determined to be T2S1, and this is followed by T1T1S1, according to a comprehensive evaluation of the mechanical state of ballast bed. This study can provide practical guidance for the combination of tamping and stabilizing operations in railway maintenance.