Investigation into Progressive Failure Mechanisms of Geosynthetic-Reinforced Pile Supported Embankment Considering Strain Softening Behaviors of Cemented Soils

There is a lack of research on stability of geosynthetic reinforced pile supported (GRPS) embankments considering the strain softening behaviors of cement-soil piles.In this paper, Concrete Model (CM), which can reflect the post-failure behavior of cement-soil, was used to model the progressive failure mechanisms of GRPS embankments.The sequences and modes of cement-soil pile failure are investigated by examining the developments of plastic zone and force changes of cement-soil piles in different locations.The results show that the CM can accurately simulate the effect of strain-softening on the shear and bending failure of cement-soil, and ignoring the strain-softening characteristics of cement-soil pile will overestimate the stability of GRPS embankments.The failure of cement-soil piles is controlled by the distribution of bending moment and axial force, the stress relief induced by failure of pile leads to a significant increase of internal force in the neighboring piles, causing the progressive failure of the neighboring piles.The piles beyond the slope shoulder are more prone to bending failure, the failure firstly occurs at the slope foot and gradually extends to the center of embankment.However, the piles inside the embankment is more prone to shear failure, and the failure direction extends from the embankment center to the slop foot.The increase in the stiffness of the reinforcement decreases the bending moment of the piles, and the failure mode of GRPS embankment changes from progressive failure to instantaneous failure.