Development of smooth particle hydrodynamics for the modelling of stresses around jack-in pile

Cyril, Perpetua Aaniya (2020) Development of smooth particle hydrodynamics for the modelling of stresses around jack-in pile. PhD thesis, University of Nottingham.

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Abstract

Jack-in pile installation generates large deformations in the surrounding soil. These deformations cause significant changes to the soil stress levels. Such variations in stresses greatly influence the pile bearing capacity. Therefore, prediction of stresses in soil during the installation phase is crucial. However, over the past, limited knowledge has been gained on soil stress field during jack-in pile installation. The experimental techniques available for obtaining soil stress measurements involve a great level of complexity. Accurate simulation of the stress field necessitates pile to be modelled as an elastic or elastic-perfectly plastic material from the soil surface considering soil-pile interaction. However, most of the numerical models in the literature based on mesh-based or mesh-free methods have adopted various simplified assumptions in modelling the phenomenon. The models have provided limited knowledge regarding the progress of soil stress distribution with pile penetration. Furthermore, Smooth Particle Hydrodynamics (SPH), a renowned and a promising numerical approach for large deformation applications is yet unexplored in this field of research. Therefore, with mounting demand in SPH, current dissertation presents the development of SPH model for simulating soil stress field around jack-in pile. Unlike the numerical models in the literature, the SPH model is introduced with minimised simplified assumptions and increased capabilities for delivering precise estimation and comprehensive understanding of the soil stress field.

For achieving the goal of this thesis, the study initially presents the development of von-Mises and Drucker-Prager constitutive models in two-dimensional (2D) SPH framework for plane stress condition. SPH models are developed comprising each of these constitutive models for examining the stresses and strains of materials under uniaxial compression. The models provide great insight into the behaviour of stresses in materials under loading. During simulation, stresses are experienced outside the yield surface. For eliminating this problem, two-dimensional tension cracking treatment and stress scaling back pressure are introduced for both criteria. Numerical results achieved utilizing the proposed SPH models establish good correlation with analytical solutions. It is found that the developed constitutive models function as fundamental computational frameworks for researchers for analysing stresses and strains in 2D plane stress materials.

Following similar approach, the dissertation further presents von-Mises and Drucker-Prager constitutive models in a complete two-dimensional SPH framework for the investigation of stresses and strains in plane strain applications. SPH models with the proposed plane strain constitutive models are applied for modelling in-plane stresses and strains in materials under uniaxial compression. Numerical results achieved through the proposed plane strain models correlate well with analytical solutions proving the effectiveness of the proposed plane strain constitutive models in simulating the stresses and strains in plane strain applications.

The thesis finally presents the development of SPH model for simulating jack-in pile installation. The model simulates pile and soil by the proposed von-Mises and Drucker-Prager constitutive models for plane strain condition. In addition to soil stress estimation, the model generates visual representation of both horizontal and vertical soil stress distribution at various pile penetration depths. Such ability of the model provides great insight into the progress of soil stress distribution with pile penetration. Furthermore, the SPH model is proposed to contain the combined ability of simulating pile as an elastic-perfectly plastic material from the soil surface to the end of pile penetration with consideration of soil-pile interaction. This minimises the simplified assumptions made in most of the numerical models in literature. Numerical results achieved with the proposed approach establish good correlation with formerly published experimental solutions. Furthermore, results published using material point method (MPM) are compared. The SPH model successfully simulates the complex phenomenon with reduced simplified assumptions providing reliable estimations and in-depth knowledge of soil stress distribution throughout the installation process. Thus, the proposed model is considered to be a promising numerical approach.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Kok, Sien-Ti
Song, Myung Kyu
Chan, Andy
Wong, Jing-Ying
Choong, Wee Kang
Keywords: smooth particle hydrodynamics, jack-in pile installation, soil stresses, constitutive models
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
Faculties/Schools: UNMC Malaysia Campus > Faculty of Engineering > Department of Civil Engineering
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Item ID: 59793
Depositing User: CYRIL, PERPETUA AANIYA
Date Deposited: 28 Jul 2020 03:38
Last Modified: 28 Jul 2020 03:38
URI: http://eprints.nottingham.ac.uk/id/eprint/59793

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