Experimental Study on the Effect of Relative Compaction on Long-term Settlement of the Embankment of High-speed Railways

초록

The objective of this paper is to present a laboratory investigation on the effect of relative compaction on the behavior of the long-term settlement of the embankment for high-speed railways. The experiment was conducted on reconstructed soil specimens using a one-dimensional compression chamber. Test samples were collected from a railway construction site and they were classified as poorly graded sand with silt and gravel (SP-SM) and silty sand (SM). The soil specimen was mixed with water and compacted in three layers in the compression chamber. Then, two steps of long-term constant loading were applied. Not only the effect of relative compaction, but also the effect of the magnitude and duration of the long-term loading on the compression and creep behavior of the embankment was analyzed. Test results show that the final settlement decreases as the load increase while the coefficient of secondary compression index (Cα) increase. Additionally, as for the creep test process, the decrement of void ratio was dependent on the magnitude of loading. It is also concluded that the long-term settlement in high-speed railways is significant because the predicted long-term settlement based on the test results exceeds the operational limit for the residual settlement of high-speed railways.