Embedment

About: Embedment is a research topic. Over the lifetime, 2441 publications have been published within this topic receiving 31444 citations.

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.

The analysis of offshore foundations subjected to combined loading

Abstract: Shallow offshore foundations, which achieve their stability through the foundation bearing on the seabed, can in most applications be idealised as large rigid circular footings subjected to vertical, horizontal and moment loading. A small strain linear-elastic perfectly-plastic three- dimensional finite element program was developed to analyse this combined loading problem. The selection of a suitable three-dimensional finite element for accurate and computationally efficient analysis was based on the element's ability to model incompressible soil conditions, using exact numerical integration. A new approach for evaluating element suitability is developed and is quantified in terms of the parameter free degrees-of-freedom (equal to the degrees-of-freedom minus the incompressibility constraints). The tetrahedron family of three- dimensional elements is found to be in general more suitable and computationally efficient than the Serendipity and Lagrangian cube families. The 20-node quadratic strain tetrahedron is adopted for all analyses presented in this thesis. For combined loading, most of the available elastic analytical solutions are for rigid circular footings placed at the surface. Finite element analyses reveal certain inadequacies in some of these solutions. The elastic numerical analyses also examine the effect of footing embedment for three cases of embedment geometry. This demonstrates that the increase in footing stiffness (reduction in displacement) due to embedment for horizontal and moment loading is developed at shallower depths, and has a greater magnitude, than for vertical loading. The stability of a rough rigid circular footing placed on the surface of an undrained clay is examined. Zero thickness interface elements, despite experiencing some numerical instability problems, were found to model the footing-soil interaction better than conventional continuum elements. However, application of interface elements to footings which can lose contact with the soil, under moment loading conditions, resulted in numerical instability of the solution. A simpler model was therefore used to define the shape of the three-dimensional failure envelope at high vertical load. Comparisons with the semi-empirical inclination factors of bearing capacity solutions are included.