Evaluation of Undrained Bearing Capacities of Bucket Foundations Under Combined Loads

Abstract

A series of three-dimensional finite element analyses was conducted to investigate the effects of the embedment depth, the non-homogeneity of clay, and combined loads on the undrained bearing capacities of bucket foundations. The undrained shear strength and Young's modulus of clay were assumed to vary linearly with depth. Meanwhile, the stress-strain response of clay was simulated using the Tresca criterion. The numerical modeling adopted in this study was verified by comparing the calculated capacities with those from previous studies. Based on the results of the finite element analyses over 1400 cases, new equations were proposed to calculate the vertical, horizontal, and moment bearing capacities as well as to define the capacity envelopes under general combined loads. Comparisons with the capacity envelopes of previous studies showed that the proposed equations properly predicted the bearing capacities of the bucket foundation by considering the effects of the non-homogeneity of clay and embedment depth.

Undrained Bearing Capacity of Suction Caissons for Offshore Wind Turbine Foundations by Numerical Limit Analysis

“…The failure envelope approach has recently been adopted to express the capacity of shallow foundations (e.g., Bransby and Yun 2009;Achmus et al 2013;Hung and Kim 2014). The loads contributing to failure are plotted in the horizontal-moment (H-M) load space (if the vertical load (V) is assumed to be constant), thus forming a failure envelope.…”

“…Figure 8 plots the normalized failure envelopes of the means of the upper and lower bound results, where M 0 is the pure moment capacity and H 0 is the pure horizontal capacity. The results are compared with the FEM results produced by Bransby and Yun (2009) (FEM-1) and Hung and Kim (2014) (FEM-2). In their analyses, the soil was modeled as an elastic perfectly plastic material and the foundations were modeled as solid, rigid bodies.…”

Vertical bearing capacity of bucket foundations in sand

“…Since soft clays are most often encountered in offshore seabeds, most numerical studies and model tests focused on bearing capacity and yield locus under combined loading in clays (Bransby and Randolph, 1999;Bransby and Yun, 2009;Gourvenec, 2008;Hung and Kim, 2014). Bransby and Randolph (1998) proposed normalized yield functions for bucket foundations in clays under combined loading based on plane strain finite element (FE) and upper bound limit analyses.…”

Long-term cyclic behavior of soils supporting offshore wind turbine foundation

“…2014). Hung and Kim (2014) suggested the bearing capacity formula for the static condition of bucket foundations on clay to be used in numerical analysis. In this paper, the long-term cyclic behavior of soils supporting offshore wind turbine bucket foundations is evaluated using numerical analyses.…”