Stability of embankment on soft subgrade reinforced by rigid piles (Ⅰ) —background and single pile analysis

Besides the commonly used sand columns, stone column and deep mixed columns, rigid piles such as plain concrete piles and reinforced concrete piles are introduced to improve the stability of embankment constructed on soft subgrade. The stability analysis of embankment on soft subgrade improved by rigid piles is performed by using 3D and 2D numerical methods. For the embankment with only one rigid pile, the results indicate that the failure mode, pile-soil interaction of single pile and its contribution to the stability of embankment highly depend on its location with respect to the embankment. When the embankment is approaching failure, the concrete piles and reinforced pile under the embankment tend to subject to bending failure rather than shear failure. The pile flexural stiffness has an important effect on the stability of embankment. Because it fails to consider the failure mechanism of single pile at different locations, the limit equilibrium method using composite shear strength will overestimate the embankment stability.