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Papers by Domenico Gallipoli

Acta geotechnica, Apr 25, 2024

Springer series in geomechanics and geoengineering, 2023

Geotechnique, Oct 1, 2009

Taylor & Francis eBooks, 2002

Springer series in geomechanics and geoengineering, 2023

Geotechnique, Oct 1, 2009

Taylor & Francis eBooks, 2002

HAL (Le Centre pour la Communication Scientifique Directe), May 9, 2022

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

HAL (Le Centre pour la Communication Scientifique Directe), May 9, 2022

E3S Web of Conferences

Raw earth is emerging as a viable building material with lower carbon emissions than conventional... more Raw earth is emerging as a viable building material with lower carbon emissions than conventional concrete and fired bricks. Raw earth is as an excellent passive hygro-thermal regulator, which improves occupants’ comfort while reducing the need for active heating/cooling installations. The coupled hygro-thermal response of earth materials is investigated by exploiting the principles of the thermodynamics of porous media and unsaturated soil mechanics. The degree of coupling between temperature and relative humidity (or water content) depends on the adopted simplifying assumptions. Some of these assumptions are valid for traditional building materials but may not be applicable to raw earth characterised by relatively high levels of liquid/gas permeability. The validity of current approaches is here assessed with reference to earth building via a simple one-dimensional transfer model, which simulates the behaviour of an unbounded earth wall subjected to time-dependent boundary conditi...

HAL (Le Centre pour la Communication Scientifique Directe), Jul 9, 2018

Computers and Geotechnics, Jun 1, 2019

A coupled hydromechanical bounding surface model predicting the hysteretic behaviour of unsaturat... more A coupled hydromechanical bounding surface model predicting the hysteretic behaviour of unsaturated soils.

E3S web of conferences, 2023

The growing pressures of climate change, increased usage and unprecedented geo-hazards impose a m... more The growing pressures of climate change, increased usage and unprecedented geo-hazards impose a modification in the way civil engineering structures are designed and constructed. This is particularly true for geotechnical works, which are very sensitive to changes of environmental conditions. For instance, the response of a pile under lateral loading is strongly influenced by the stiffness and strength of the first few metres of soil below the surface, which are often partly saturated. To consider this effect, the present paper describes an analytical method, which extends the well-known Broms approach to predict the lateral capacity of piles in unsaturated soils. More specifically, the proposed method considers the combined effects of the position of the ground water table and the extra strength of the partially saturated soil above it. Compared to Broms approach, the solution introduces four additional non-dimensional parameters that relate the soil-water retention behaviour to the geometry of the pile. The method provides a direct evaluation of the lateral pile capacity in partly saturated soils, which can be used as a basis for more accurate design.

E3S web of conferences, 2023

This paper extends the modified Cam-Clay model to describe the behaviour of unsaturated soils by ... more This paper extends the modified Cam-Clay model to describe the behaviour of unsaturated soils by replacing the effective stress with the scaled stress. The scaled stress accounts for the mechanical effect of capillarity by factoring Bishop's stress with a power function of degree of saturation. The extended modified Cam-Clay model postulates the existence of a yield curve in the mean scaled stress ̅-deviatoric scaled stress ̅ plane. Coherently with the modified Cam-Clay model, the stress-strain behaviour is predicted by means of an elastic law inside the yield curve. As the scaled stress state evolves onto the yield curve, the behaviour becomes elasto-plastic and this is modelled by a plastic flow rule combined with a volumetric hardening law. The extended modified Cam-Clay model is then validated against experimental data published in the literature. Results show that the proposed approach is capable of well predicting the mechanical behaviour of unsaturated soils during triaxial loading. Future work will be directed at further validating the present formulation along different stress paths as well as accounting for the combined effect of partial saturation and cementation within a critical state framework based on bounding surface plasticity.

Computers and Geotechnics, Mar 1, 2023

HAL (Le Centre pour la Communication Scientifique Directe), Aug 3, 2018

HAL (Le Centre pour la Communication Scientifique Directe), Oct 25, 2016

CRC Press eBooks, Sep 23, 2020

Acta geotechnica, Apr 25, 2024

Springer series in geomechanics and geoengineering, 2023

Geotechnique, Oct 1, 2009

Taylor & Francis eBooks, 2002

Springer series in geomechanics and geoengineering, 2023

Geotechnique, Oct 1, 2009

Taylor & Francis eBooks, 2002

HAL (Le Centre pour la Communication Scientifique Directe), May 9, 2022

E3S Web of Conferences

HAL (Le Centre pour la Communication Scientifique Directe), Jul 9, 2018

Computers and Geotechnics, Jun 1, 2019

E3S web of conferences, 2023

Computers and Geotechnics, Mar 1, 2023

HAL (Le Centre pour la Communication Scientifique Directe), Aug 3, 2018

HAL (Le Centre pour la Communication Scientifique Directe), Oct 25, 2016

CRC Press eBooks, Sep 23, 2020

Compacted soils are relevant to many geotechnical applications, from earth dams to infrastructure... more Compacted soils are relevant to many geotechnical applications, from earth dams to infrastructure embankments, nuclear waste disposal and rammed-earth buildings. Every geotechnical structure made of compacted soils will include sections that remain partly saturated at least for a period of its service life. Improved understanding of this fast growing area can contribute to the improved design of earth structures/fills by maximizing the use of locally sourced soils, with consequent gains in safety, cost and sustainability of future building practice. The sixteenth Géotechnique Symposium in Print focused on the study of compacted unsaturated soils, which are at the core of geotechnics and have been at the forefront of research for many years, providing a unique scientific forum for the exchange of the latest knowledge and best practice between academia and industry. This book brings together all the Symposium papers from leading international researchers, published in Geotechnique, the keynote speeches presented at the Symposium, at the Institution of Civil Engineers on 20 June 2011, and a selection of questions posed by delegates during the Symposium, together with answers from presenters. Partial Saturation in Compacted Soils provides a comprehensive overview of recent advances in unsaturated soil mechanics, ranging from material testing to modelling and analysis of engineering boundary value problems, providing further insight into the rapidly developing topic of unsaturated soil mechanics and its application to compacted fills and serving as an invaluable reference for engineers and researchers for years to come.

Unsaturated Soils: Advances in Geo-Engineering comprises 136 contributions from leading internati... more Unsaturated Soils: Advances in Geo-Engineering comprises 136 contributions from leading international researchers and practitioners, presented at the First European Conference on Unsaturated Soils (Durham, UK, 2-4 July 2008). The papers report on the latest advances in geo-engineering aspects of unsaturated soils. It is the first collection to focus on research developments within Europe, where a resurgence of interest in unsaturated soil behaviour has lead to major advances. The volume is divided into five sections: - Advances in testing techniques, - Engineering behaviour, - Constitutive modelling, - Numerical modelling, -Case histories. The areas of application include slope stability, foundations, dams, contaminated land, landfill and nuclear waste repositories. The section on advances in testing techniques includes recent developments in high capacity tensiometers, spatial Time Domain Reflectometry and Environmental Scanning Electron Microscopy. The section on engineering behaviour includes the latest findings concerning factors affecting the water retention surface; volume change of soils during wetting and drying; peak, ultimate and residual strength of soils; small strain modulii and shear wave responses. The sections on Constitutive and Numerical modelling address major developments in coupled thermo-hydro-mechanical elasto-plastic models. Unsaturated Soils: Advances in Geo-Engineering contains 90 papers from 15 countries within Europe with a further 46 contributions from 15 other countries, and is a comprehensive collection that will be essential referencematerial for geo-engineers around the world.

PhD Thesis of Domenico Gallipoli, 2000

The thesis focuses on three different areas: development of constitutive models for unsaturated s... more The thesis focuses on three different areas: development of constitutive models for unsaturated soils, improvement of the finite element code “Compass” for coupled flow-deformation analysis involving unsaturated soils and application of the improved code to the simulation of pressuremeter tests in unsaturated soils.
On the constitutive side, a unique relationship is proposed between degree of saturation, suction and specific volume by introducing dependency on specific volume in the simplified van Genuchten equation. This is a significant improvement over the common assumption of a state surface expression for degree of saturation. If combined with an elasto-plastic stress-strain model predicting the variation of specific volume, the proposed relationship is capable of reproducing irreversible changes of degree of saturation and changes of degree of saturation experimentally observed during shearing. Predictions show very good agreement with experimental results from tests on compacted Speswhite Kaolin published in the literature.
On the numerical side, a number of changes to the code “Compass” have been performed. The new relationship for degree of saturation is implemented in the code and the implementation is validated against three benchmark problems. Use of the new relationship for degree of saturation results in significantly different predictions to those obtained if a conventional state surface expression for degree of saturation is used (as present in the original code).
Implementation of the water and air continuity equations in “Compass” has been corrected by expressing these equations in terms of flux velocities relative to the soil skeleton. This is the form in which the equations should be expressed if they are to be combined with Darcy’s law for liquid and gas flows. The simulation of a notional laboratory test shows that the incorrect combination of Darcy’s law with absolute flux velocities, as present in the original code, causes significant errors.
The convergency algorithm at constitutive level employed in the code has been corrected by introducing residual flux terms in the two flow equations, analogous to residual forces in the equilibrium equation. These terms must be taken into account if a convergency algorithm for an elasto-plastic stress-strain model is used and the relationship assumed for variation of degree of saturation involves any dependency on net stresses. A numerical study of a notional laboratory test shows that omission of residual flux terms results in substantial errors and may cause failure to converge.
The plane_strain formulation of code “Compass” has been corrected by imposing the condition of nullity only on the out-of-plane component of the total strain rate vector instead of the out-of-plane component of each single contribution to the total strain rate, as was done in the original code. Such inconsistency, due to the history of development of finite element programs, also appears in other examples published in the literature. Numerical simulations of two types of bi-axial tests show that significantly different results are generally predicted by the correct and incorrect formulations, and also provide an explanation why this type of error was difficult to detect in codes implementing traditional models for saturated soils.
The potential of the enhanced version of code “Compass” for analysing boundary value problems is demonstrated by simulations of pressuremeter tests in unsaturated soil. This study also provides some initial insight into the interpretation of pressuremeter tests in unsaturated soil by simulating tests at different loading rates in a normally consolidated soil. The mechanical behaviour of the soil is represented by the elasto-plastic Barcelona Basic Model of Alonso, Gens and Josa (1990) while the variation of degree of saturation is modelled by the new relationship proposed in the thesis. The entire range of loading rates, from undrained to fully drained (with respect to liquid), is simulated. Relatively small changes of suction are predicted even in the fastest test and the computed cavity pressure-cavity strain relationships are all very similar regardless of loading rate. It may therefore be possible to model even rapid pressuremeter tests in unsaturated soils as a drained (constant suction) process. Further work is required to investigate the generality of this conclusion.

This presentation was held in the occasion of the doctoral school in Bayonne, France on the 26 Ma... more This presentation was held in the occasion of the doctoral school in Bayonne, France on the 26 May 2015. This school was the prelude to the 33rd edition of the "Rencontres Universitaires de Génie Civil" organized by the French University Association of Civil Engineering in collaboration with the Université de Pau et des Pays de l'Adour.

The lecture in this video provides an introduction to the phenomena of capillarity in unsaturated soils and to the relevant constitutive laws of material behaviour. The lecture also provides a brief description of the techniques employed for the measurement of suction in unsaturated soils.