MODEL TEST ON STABILITY FAILURE OF SHORT-CORED STIFFENED DEEP MIXED COLUMN-SUPPORTED EMBANKMENT

Stiffened deep mixed column(SDCM)with short core pile is commonly used in application. However, people have limit understanding regarding the failure mode and mechanism of such column-supported embankment over soft clay, leading to a challenging to reasonably evaluate the stability of such column-supported embankment in design. This paper conducts a scaled-down 1 g model test of short-cored stiffened deep cement mixed columns-supported embankment. The progressive failure modes of columns and global failure characteristics of embankment are detected according to comprehensive analyses of the change of conductive path pasted in core piles, vertical stresses on pile and surrounding soil, displacement of embankment combined with PIV technology. The results show that the embankment load is mostly carried by the core pile under embankment crest. With the increase of surcharge, the loading shear action of column reduces, but the core pile still has certain loading shear action after the embankment failure. In the process of embankment failure, the column under the embankment crest fails by compression and bulging failure occurs below the core pile section. The columns under the embankment slope fails by bending. The slip surface did not completely pass through the failure positions of columns.