Three-Dimensional Finite-Element Lower Bound Solutions for Lateral Limit Load of Piles Embedded in Cross-Anisotropic Clay Deposits

This paper aims to assess the lateral limit load (H) of a pile embedded in cross-anisotropic clay deposits by a three-dimensional (3D) finite-element lower bound theorem in association with the second-order cone programming method. The lower bound solutions for a laterally loaded pile that is embedded in an anisotropic soil deposit can be found by formulating the element equilibrium, discontinuity shear and normal stresses equilibrium, boundary conditions, yield function, and optimizing the objective function using the second-order cone programming method and an iterative-based update procedure. The calculation procedure ceases when the discrepancy between the successive solutions satisfies the convergence criterion. Three different anisotropy models that include linear, sine, and cosine functions will be exploited to address the effect of cross-anisotropy. A parametric study will be conducted to capture the coupled effects of anisotropy degree (beta), embedment length (L), and adhesion factor (alpha). The findings of this paper will be compared with those reported in the literature. The comparative analyses illustrated that the sine and cosine anisotropy functions yielded the least and most H predictions with beta lower than 1, respectively. However, for soils with beta higher than 1, the linear and the sine functions provided the lowest and the highest H predictions, respectively. (c) 2021 American Society of Civil Engineers.