Publications
249 results found
Grammatikopoulou A, Zdravkovic L, Potts DM, 2007, The effect of the yield and plastic potential deviatoric surfaces on the failure height of an embankment, GEOTECHNIQUE, Vol: 57, Pages: 795-806, ISSN: 0016-8505
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- Citations: 22
Kontoe S, Zdravkovic L, Potts DM, 2007, An assessment of time integration schemes for dynamic geotechnical problems, Computers and Geotechnics, Vol: 35, Pages: 253-264, ISSN: 1873-7633
The performance of the generalized-α, Newmark, HHT and WBZ time integration schemes is examined for a boundary value problem of a deep foundation subjected to various earthquake loadings. The effects of the frequency content of the earthquake excitation and the natural frequency of the numerical model on the performance of the above-mentioned algorithms are considered. The various time integration methods are compared in terms of accuracy, the ability to control high-frequency dissipation and run time. It is concluded from the finite element analysis results that the generalized-α scheme has superior qualities compared to the other algorithms investigated.
Monroy R, Ridley A, Dineen K, et al., 2007, The suitability of the osmotic technique for the long-term testing of partly saturated soils, GEOTECHNICAL TESTING JOURNAL, Vol: 30, Pages: 220-226, ISSN: 0149-6115
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- Citations: 29
Zdravkovic L, Tsiampousi A, Potts DM, 2007, Effect of wall and soil permeability on the long-term ground movements adjacent to a deep excavation, 10th International Conference on Numerical Methods in Geomechanics, Pages: 589-594
Taborda S, Zdravkovic L, Kontoe S, 2007, The importance of cyclic nonlinear models in dynamic finite element analysis, Netherlands, 10th Symposium on Numerical Models in Geomechanics, Publisher: Balkema, Pages: 743-749
Monroy R, Zdravkovic L, Ridley A, 2007, Fabric changes in compacted London clay due to variations in applied stress and suction, 2nd International Conference on Mechanics of Unsaturated Soils, Publisher: SPRINGER-VERLAG BERLIN, Pages: 41-+, ISSN: 0930-8989
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- Citations: 3
Kontoe S, Zdravkovic L, Potts DM, et al., 2007, The use of absorbing boundaries in dynamic analyses of soil-structure interaction problems, Thessaloniki, Greece, Proceedings of the 4th International Conference on Earthquake Geotechnical Engineering
Grammatikopoulou A, Zdravkovic L, Potts DM, 2007, Some strengths and weaknesses of “bubble” models, International Workshop on Constitutive Modelling - Development, Implementation, Evaluation and Application, in Constitutive Modelling, Pages: 1-10
Georgiadis K, Potts DM, Zdravkovic L, 2007, Numerical study of the stability of a partially saturated soil slope, 10th International Symposium on Numerical Models in Geomechanics (NUMOG X), Publisher: TAYLOR & FRANCIS LTD, Pages: 545-+
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- Citations: 1
Freitas TMB, Potts DM, Zdravkovic L, 2007, A numerical study on the effect of ageing on undrained bearing capacity, 10th International Symposium on Numerical Models in Geomechanics (NUMOG X), Publisher: TAYLOR & FRANCIS LTD, Pages: 419-424
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- Citations: 1
Vaughan PR, Standing J, Zdravkovic L, 2006, The effect of compaction on bulk permeability of stiff clay and mudrock - Field experience from embankment dams, Pages: 797-807
The permeability of in-situ clays and soft mud rocks is strongly affected by slightly open fissures. These are difficult to discover from site investigation as the permeability of the parent intact material Is very low. This is measured by laboratory tests and, often, by in-situ tests. It is difficult to prove the absence of open fissures and low bulk permeability. This causes uncertainty in the use of these materials as impermeable seals. However, field experience is that when these materials are placed as fills using modern plant, a uniform low permeability results. There is much experience in the construction of the cores and fills of embankment dams. This experience is reviewed.
Grammatikopoulou A, Zdravkovic L, Potts DM, 2006, The pre-failure deformation of an embankment predicted by two kinematic hardening models, Pages: 447-453
This paper presents a comparison of the pre-failure behaviour of an embankment when its clay foundation is modelled with two kinematic hardening models. The paper shows that the pre-failure deformations are not only influenced by non-linearity but also by the stiffness response predicted in both compression and extension paths. © 2006 Taylor & Francis Group.
Edwards D, Potts D, Zdravkovic L, 2006, Paper: The bearing capacity of a circular footing under 'punch-through' failure, Ground Engineering, Vol: 39, Pages: 42-44, ISSN: 0017-4653
Finite element analyses performed with the Imperial College Finite Element Program (ICFEP) were carried out to perform a parametric study of the bearing capacity of a circular footing on layered clays. Eight noded isoparametric solid elements and six noded, zero thickness interface elements were used with reduced integration. A modified Newton-Raphson approach with an error controlled sub-stepping stress point algorithm was used to solve the non-linear FEAs. The data generated showed existing methods of analysis to predict overly conservative foundation capacities.
Edwards D, Potts DM, Zdravkovic L, 2006, The bearing capacity of a circular footing under punch-through failure, Ground Engineering, Pages: 42-44
Grammatikopoulou A, Zdravkovic L, Potts D M, 2006, General formulation of two kinematic hardening constitutive models with a smooth elastoplastic transition, INTERNATIONAL JOURNAL OF GEOMECHANICS, Vol: 6, Pages: 291-302, ISSN: 1532-3641
Zdravkovic L, Potts DM, Shin JH, 2006, Formulation and application of a generalised gravity vector in the FSAFEM, 1st South-East European Conf. on Computational Mechanics, SEECCM-06, Pages: 291-297
Zdravkovic L, Potts DM, 2005, Parametric finite element analyses of suction anchors, Pages: 297-302
This paper presents the results from a series of three-dimensional (3D) finite element parametric studies on suction anchors in clay. The objective is to investigate the effects of a number of factors on the pull out capacity of suction anchors, namely the position of the attachment point, inclination of the pull out force and anchor geometry. A typical soft clay was considered as the seabed soil and it was simulated using a form of the modified Cam clay model. The results identify the optimum position of the anchoring point, as well as the optimum inclination of the pull out force. © 2005 Taylor & Francis Group.
Edwards DH, Zdravkovic L, Potts DM, 2005, Depth factors for undrained bearing capacity, GEOTECHNIQUE, Vol: 55, Pages: 755-758, ISSN: 0016-8505
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- Citations: 41
Lollino P, Cotecchia F, Zdravkovic L, et al., 2005, Numerical analysis and monitoring of Pappadai dam, CANADIAN GEOTECHNICAL JOURNAL, Vol: 42, Pages: 1631-1643, ISSN: 0008-3674
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- Citations: 18
Shin JH, Potts DM, Zdravkovic L, 2005, The effect of pore-water pressure on NATM tunnel linings in decomposed granite soil, CANADIAN GEOTECHNICAL JOURNAL, Vol: 42, Pages: 1585-1599, ISSN: 0008-3674
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- Citations: 47
Zdravkovic L, Potts DM, St John HD, 2005, Modelling of a 3D excavation in finite element analysis, GEOTECHNIQUE, Vol: 55, Pages: 497-513, ISSN: 0016-8505
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- Citations: 103
Zdravkovic L, Potts DM, 2005, Finite element investigation of non-uniformities in hollow cylinder experiments, 11th International Conference on Computer methods and Advances in Geomechanics, Publisher: Patron Editore, Pages: 251-258
Hicks MA, 2005, Editorial, Géotechnique, Vol: 55, Pages: 1-2, ISSN: 0016-8505
Hicks MA, Zdravkovic L, Breysse D, et al., 2005, Risk and variability in geotechnical engineering, GEOTECHNIQUE, Vol: 55, Pages: 1-2, ISSN: 0016-8505
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- Citations: 7
Georgiadis K, Potts DM, Zdravkovic L, 2005, Three-dimensional constitutive model for partially and fully saturated soils, International Journal of Geomechanics, Vol: 5, Pages: 244-255, ISSN: 1532-3641
Constitutive models for partially saturated soils often assume linear relationships for the variation of shear strength with suction and the shape of the partially saturated isotropic compression lines. It has been established, however, that for some soils these relationships are nonlinear. The shape of the isotropic compression line for partially saturated conditions is of particular importance, as it is directly related to the amount of potential collapse that a soil will experience upon wetting. When boundary value problems are analyzed, ignoring this nonlinearity can lead to very inaccurate predictions, and such models are of limited applicability. None of the current models have been demonstrated to predict collapse behavior in a satisfactory manner, especially at high values of stress and suction. In this paper, an exponential expression for partially saturated isotropic compression lines is implemented in an existing elasto-plastic framework for saturated and partially saturated soils. As a result, the constitutive relationship presented here is more flexible in its ability to model the collapse behavior of partially saturated soils over a larger range of suctions and stresses. A nonlinear expression is also adopted for the variation of shear strength with suction. In addition, a number of other refinements to the existing framework are introduced. Also presented in this paper are the results of a series of single element finite-element analyses. These results demonstrate the model's capabilities and added flexibility. International Journal of Geomechanics © ASCE.
Kontoe S, Zdravkovic L, Potts DM, 2004, Performance of the generalised: integration method in dynamic geotechnical problems, Leiden, Proceedings of the 9th international conference numerical models in geomech - NUMOG IX, Ottawa, 2004, Publisher: Balkema, Pages: 211-216
Zdravkovic L, Potts DM, Lui NWT, 2004, Numerical investigation of the effect of foundation depth on settlement, Leiden, Proceedings of the 9th international conference numerical models in geomech - NUMOG IX, Ottawa, 2004, Publisher: Balkema, Pages: 499-504
Georgiadis K, Potts DM, Zdravkovic L, 2004, Modelling the shear strength of soils in the general stress space, COMPUTERS AND GEOTECHNICS, Vol: 31, Pages: 357-364, ISSN: 0266-352X
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- Citations: 22
Kontoe S, Zdravkovic L, Potts DM, 2004, Performance of the generalised: integration method in dynamic geotechnical problems, Leiden, Proceedings of the 9th international conference numerical models in geomech - NUMOG IX, Ottawa, 2004, Publisher: Balkema, Pages: 211-216
Zdravkovic L, Neo JL, 2004, The interaction between strip surface footings on clay, Leiden, Proceedings of the 9th international conference numerical models in geomech - NUMOG IX, Ottawa, 2004, Publisher: Balkema, Pages: 487-492
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