Cumulative settlement of track subgrade in high-speed railway under varying water levels

Water-level variation in the subgrade of high-speed railway influences the cumulative settlement of the subgrade. Full-scale model test on high-speed railway under varying water levels within the subgrade was conducted in this research. Dynamic soil pressures in different depths within the subgrade and cumulative settlements of subgrade were measured under different train speeds. The results demonstrated that the dynamic soil pressure increases significantly after the first wetting-drying cycles and then remains stable. The measured dynamic soil pressure was compared to the requirements in the current design method. Increasing train speed leads to higher cumulative settlement. Furthermore, a modified model is proposed in the article for the determination of cumulative settlement considering the influence of initial stress state, material properties of subgrade, and dynamic stresses of train loadings.