Mechanical Characteristics of Ballast Bed under Dynamic Stabilization Operation Based on Discrete Element and Experimental Approaches

Abstract

To study the mechanical characteristics of ballasted bed under dynamic stability, a three-dimensional discrete element model of ballasted bed with 1000 mm × 700 mm × 550 mm is established based on the discrete element method. Meanwhile, a simulation test bench with the same size is built for simulation analysis and experimental research. The variation law and trend of settlement, lateral resistance, and compactness of ballasted bed under different excitation frequencies are analyzed comprehensively. The results show that when the excitation frequency is constant, the lateral resistance of sleeper, the settlement of sleeper, and the compactness of track bed under sleeper increase first and then tend to be stable. With the increase in horizontal excitation frequency, lateral resistance of ballast bed, sleeper settlement, and compactness first increase and then decrease after stable operation. The values of these parameters are maximized when the excitation frequency is 36 Hz which is the relative optimal horizontal excitation frequency of this model.

Discrete Element Analysis on Mechanical Properties of Ballast Bed by Tamping in Railway Turnout Areas

“…Since the tamping device, sleepers, and ballast particles are in direct contact, in order to ensure the reliability of contact parameters, the calculation parameters of the simulation model are drawn up by referring to Refs. [18][19][20] and [30][31][32] and by means of control variable method, as shown in Table 3.…”

Influence of the Compactness on the Mechanical Properties of Ballasted Track

“…[8] analyzed the coupling characteristics of sleeper-ballast bed under the dynamic stabilization unit operation, and found that the relationship between the vertical force, the excitation frequency and the ballast uniformity, and got that the vertical downward pressure is in the range of 100-125kN, and the excitation frequency is in the range of 30-40Hz. Wang et al [9] analyzed the dynamic response of the ballast bed under dynamic stabilization and found that the ballast stability is better when the stabilization unit operation frequency is 36Hz. In the above study, the initial ballast compactness is a single value, and the actual railway line in the initial ballast compactness is different, therefore, this paper studies the dynamic stabilization operation of different initial ballast compactness on the impact of the ballast stability, so that in the actual operation of the dynamic stabilization unit parameter adjustment is more targeted and directional, and provide certain reference for the dynamic stabilization vehicle and even large-scale railway road maintenance machinery operations.…”

Experimental analysis of ballast bed state in newly constructed railways after tamping and stabilizing operation

“…After the first tamping operation, the longitudinal and lateral resistance of the ballast bed decreased by 3.0 % and 4.3 % respectively, and the stiffness and damping increased by 21.5 % and 43.8 % respectively. Wang et al [15] used a ballast box and small vibrator to simulate the stabilizing operation and analyzed the settlement, lateral resistance, and compactness of ballast beds at various frequencies. The results show that a high excitation frequency (36 Hz ~ 40 Hz) is detrimental to ballast stabilizing.…”