Influence of deep-cement-mixing column rows on the performance of geosynthetics-reinforced column-supported railway embankment

Knowledge regarding the stability of geosynthetics-reinforced column-supported railway embankment (GRCSE) on soft foundation is of great significance for transportation infrastructure safety design, and deep-cement-mixing (DCM) columns constructed under the toe of an embankment is used to improve the performance of GRCSEs. This study conducted two centrifuge model tests to simulate the failure of a constructed embankment in a 40-g environment. The failure mechanism of each component in the GRCSE system and the effect of additional DCM column rows near the embankment toe on the GRCSE performance were analysed. The particle image velocimetry (PIV) technique was used to draw further insights from the results. The tests revealed that a failed column within the GRCSE system led to the progressive failure of adjacent columns, coupled with the progressive and retrogressive propagation of shear strains in the soft soil, which resulted in embankment collapse. The addition of DCM column rows near the embankment toe reduced the local shear strain accumulation in the soft foundation and thus improved the overall stability. The incremental tensile strain of the geosynthetic reinforcement in various phases was different in the cases with and without additional DCM column rows. Moreover, the effects of various factors of DCM rows, including row number and length, on the GRCSE stability were numerically analysed.