Prediction of ballast bed settlement and compactness increment based on the response surface method

The influence of dynamic stabilisers on the behaviour, settlement and density of ballast beds was investigated. The parameters for the ballast bed contact were obtained using the quadratic regression orthogonal rotational combination test and the inclined plane method. A coupling model of the dynamic stabiliser and railway track was established using coupling of the discrete-element method, finite-element method and multi-body dynamics, and a test platform was created to validate the accuracy of the simulation model. The response surface method was used to develop a prediction model with stabilisation operation parameters and the initial ballast bed density as the research factors, while the settlement of the ballast bed and the increase in ballast bed density were evaluation indices. The results indicated that the sleeper–ballast contact parameter is crucial for the ballast bed contact parameters. The recovery, static and rolling friction coefficients between the sleeper and ballast were 0.70, 0.59 and 0.18, respectively, while these coefficients between the ballast materials were 0.69, 0.84 and 0.12, respectively. The prediction error rates for the ballast bed settlement and the increase in ballast bed compactness were 6.95% and 10.99%, respectively.