Stability Analysis Method for a Prestressed Railway Embankment considering the Additional Stresses Propagation Effect

To evaluate the stability of a prestressed railway embankment (PRE), approximate solutions for the additional normal and shear stresses on an arbitrary potential sliding surface of a PRE are first derived using the elastic theory, by which the propagation effect of additional stresses due to the prestressing loads is appropriately considered. Then, a limit equilibrium slice method incorporating the additional stress effect, equivalent interslice forces, track weight, and train axle load but avoiding repeated iteration calculations is developed to analyze the PRE stability. The additional stress solutions are also introduced to modify three commonly used conventional slope stability analysis methods, and comparative analyses were performed to investigate the applicability of the proposed method. The results showed that the differences between the safety factor (F-s) of a PRE evaluated using the proposed and modified methods were within 2% in this study and the values were less than those yielded by the conventional methods because of the partial negative effect of the additional normal and shear stresses on a few slices around the lateral pressure plate (LPP). Besides, the adaptive genetic algorithm was introduced to search the critical sliding surface of the PRE. Finally, the effect of reinforcement pressure on the stability of a PRE was investigated, where the results indicated that the F-s of the PRE increased from 1.323 to 1.626 with an increase of the reinforcement pressure from 0 to 200 kPa, while the PRE gradually varies from potential integral instability to potential local instability. The accurate and efficient determination of the additional stresses on the sliding surface is important in analyzing the PRE stability, and the developed method can provide an easy-to-use and relatively safer stability analysis method for the design of a PRE.