Average errors depending on calculation method.

The cement-mixed gravel, which is used in the construction of railway embankment, is a relatively more expensive material compared to sandy soil. Having said that, it is used where small residual settlement is required for example, abutment transition zone, due to characteristic of higher strength than sandy soil. In this paper, the time-dependent settlement were evaluated using field data measured over a long period of time at two RSR (Reinforced Subgrade for Railways) construction sites using two different backfill materials (sandy soil and cement-mixed gravel). The embankment settlement with cement-mixed gravel as a backfill material was reduced by 78% compared to that with sandy soil. Further, the period for stabilizing the embankment before installation of the railway track was significantly reduced with cement-mixed gravel as a backfill material.