The rail network invariably encounters soft subgrades consisting of shallow estuarine clayey deposits. Cyclic loading generated by the passage of trains causes deformation and corresponding development of excess pore water pressure (EPWP), which dissipates during the rest periods between two consecutive trains. This paper presents an experimental study describing the effect of yield stress and EPWP responses upon intermittent cyclic loading (i.e. with rest periods), and the associated consolidation with the combination of vertical and radial drainage by way of a prefabricated vertical drain (PVD). Based on the laboratory data, the normalised yield stress for cyclic loading (NYCL) is introduced as an insightful parameter to define a novel empirical relationship between the yield stress, cyclic stress amplitude and the initial effective stress. The experimental results indicate that, as the NYCL increases, the peak EPWP decreases and, during the rest periods, the EPWP reaches a stable equilibrium faster without causing further settlement. Furthermore, this study demonstrates that the accumulated EPWP caused by cyclic loading can be further reduced when using a larger width of PVD for a given unit cell radius. An analytical model inspired by empirical parameters for predicting EPWP is proposed, capturing the effects of NYCL and the PVD characteristics.

Railway transportation is widely recognized as an environment-friendly and sustainable means for conveying freight and passengers over long distances. This article investigates the effectiveness of utilizing scrap tire rubber granules and geosynthetics to enhance track performance in response to the growing demands for railway transport and the consequent escalation of train-induced loading. A multi-faceted methodology, incorporating experimental, numerical, and analytical techniques, is employed to examine the efficacy of these sustainable approaches. Results from three-dimensional (3D) finite element (FE) analyses conducted on slab tracks for high-speed railways reveal that the addition of a resilient layer, comprising scrap tire rubber granules, reduces vertical stress within the track substructure. Laboratory investigations on an innovative composite material consisting of soil, scrap rubber granules, and polyurethane demonstrate its potential to enhance track performance. Findings from two-dimensional (2D) FE analyses conducted on pile-supported railway embankments highlight an enhanced transfer of load to the pile head following the installation of a geogrid layer at the embankment base. Finally, the results from the analytical approach indicate a reduction in track settlement and a decrease in the track geometry degradation rate on reinforcing the ballast layer with 3D cellular geoinclusion. The novelty of this study lies in the comprehensive assessment of the innovative composite material under drained and cyclic loading conditions, the investigation of the influence of train loading on geosynthetic tension and the load transfer mechanism in railway embankments, and the development of an innovative computational methodology capable of assessing the effectiveness of 3D cellular inclusions in improving the ballasted railway track performance. The findings from this article underscore the effectiveness of these sustainable approaches in mitigating the challenges posed by increased loads on railway tracks, providing valuable insights for the ongoing efforts to optimize railway transportation infrastructure.