Numerical analyses of two different geotechnical problems, namely a bridge abutment and a geosynthetic reinforced embankment are presented in this thesis. Settlement, bearing capacity and slope stability are the major factors that need to be considered in the design of a foundation near a sloped fill. In this thesis, the behaviour of a small scale model footing located near the shoulder of a sloped fill was investigated numerically. Single and multiple layers of geogrid were used to reinforce the sloped fill, and their effects on the load-deformation behaviour and bearing capacity of the footing were explored. The analyses showed 80%, 168%, 295% and 375% maximum improvement in the ultimate bearing capacity with 1, 2, 3 and 4 reinforcement layers respectively. This maximum improvement depends on the embedment depths of the reinforcement layers below the foundation and the suggested optimal depths are discussed. Typically, greatest improvement in ultimate bearing capacity with a single layer of reinforcement was obtained when the reinforcement was at a depth between 0.50 and 0.75 times the foundation width. Similarly, highest ultimate bearing capacity with 2 reinforcement layers was predicted when the spacing between them was 1.0 times the width of the foundation. However, higher settlement was estimated at failure for the reinforced sloped fill than the unreinforced one. The second problem investigated was the three-dimensional (3D) analysis of Sackville embankment, a geosynthetic reinforced embankment on soft soil. Previous analyses using two-dimensional (2D) numerical modelling of Sackville embankment indicated potential 3D effects affecting the performance of this embankment. Therefore, 3D analysis incorporating geometric variations of Sackville embankment foundation soil, anisotropic model for fluid flow, mobilization of geotextile stresses in minor direction and the boundary effects (lateral directions) were taken into account in this analysis. The predicted performance of Sackville embankment were compared with the field data and the previously reported 2D analysis results in terms of vertical and horizontal displacements and excess pore pressures in the foundation soil, and geotextile stresses, strains and displacements. Better overall predictions of the Sackville embankment performance was obtained from this 3D analysis than the previous analysis reported in the literature.
| Identifer | oai:union.ndltd.org:ADTP/240839 |
| Date | January 2008 |
| Creators | Thanapalasingam, Jegan, Aerospace, Civil & Mechanical Engineering, Australian Defence Force Academy, UNSW |
| Publisher | Awarded by:University of New South Wales - Australian Defence Force Academy. School of Aerospace, Civil and Mechanical Engineering |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Jegan Thanapalasingam, http://unsworks.unsw.edu.au/copyright |
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