Effects of Wall Embedded Length Ratio and Wall Thickness Ratio on Undrained Stability of Cantilever Piled Walls

Abstract

This paper presents a parametric study of the undrained stability of cantilever piled walls embedded in homogeneous clay. The cantilever piled walls are modeled by the 2 dimensional plane strain condition, and their analyses are carried out by the commercial finite element software, PLAXIS2D. The piled wall is considered to have finite thickness, and thus is also modeled as a volume element with the Mohr-Coulomb material. The strength reduction method is used to simulate the limit state or failure condition of a cantilever piled wall in finite element analysis. The dimensional input parameters of this problem include excavated depth (H), embedded length (L), thickness of piled wall (D), soil unit weight (g), and undrained shear strength (s_u). The results of this study are summarized in the form of design charts of dimensionless parameters, including stability number (gH/s_u), wall embedded length ratio (L/H), wall thickness ratio (D/H), ratio of maximum shear force (V_max/s_uD), and ratio of maximum bending moment (M_max/s_uD²). For the stability number, it was found that L/H has more significant effects on this term than D/H. For both ratios of maximum shear force and maximum bending moment, an increase in L/H and D/H give rise to nonlinear increases and decreases in those ratios, respectively. Some differences in stability number between plate and solid element modelling can be observed in different ratios of wall thickness.