Jaime Santos - Academia.edu (original) (raw)
Papers by Jaime Santos
Journal of Mathematical Physics, 2011
RESUMO Os acessos rodoviários de ligação da Plataforma Logística de Lisboa Norte (PLLN) à Auto-es... more RESUMO Os acessos rodoviários de ligação da Plataforma Logística de Lisboa Norte (PLLN) à Auto-estrada do Norte e à Estrada Nacional 1 situam-se na bacia aluvionar da margem direita do Rio Tejo, sendo, por isso, muito condicionante para a concepção e dimensionamento das obras a elevada espessura das aluviões lodosas, que chega a atingir 34 m. Entre as várias soluções de tratamento do terreno de fundação preconizadas destaca-se a utilização de aterros de pré-carga, associados ou não a geodrenos verticais. No presente artigo descrevem-se os critérios e procedimentos de dimensionamento dos aterros de pré-carga associados a geodrenos (afastamento da malha de geodrenos, altura dos aterros, tempo de actuação das pré-cargas e a utilização de GeoLeca) para a aceleração do processo de consolidação na fase de construção, visando reduzir para valores toleráveis os assentamentos residuais durante a vida útil da obra.
Journal of Earthquake Engineering, May 2, 2012
The resonant-column test is known as the standard laboratory test to obtain the dynamic propertie... more The resonant-column test is known as the standard laboratory test to obtain the dynamic properties of soils. This test is performed on a cylindrical specimen subjected to a triaxial stress state while a harmonic force is applied and the output vibration is measured. There are other types of tests, which can be performed in the RC apparatus by the automation of the process. In this study, two tests were implemented: the first one uses a sine sweep signal (frequency increases with time); the second one uses sine signal at constant frequency, but the amplitude is modified until a strain level previously defined is obtained. The modulus and damping ratio are simultaneously found by the solution of a transcendental equation in complex variable, where the resonance condition is not necessary to obtain the dynamic properties. Tests carried allow to recognize the potentialities of the developed tests.
The aim of this paper is to present a newly implemented D interface model, compatible with the EC... more The aim of this paper is to present a newly implemented D interface model, compatible with the ECP elastoplastic soil model, and its interest in the comprehension of the load transfer mechanisms. The paper will be developed in two parts. First, the soil-structure interface modelling is focused. The general hypothesis of the model is presented and described. The Interface model is then first tested by modelling different soil-120 120structure interface characterization shear tests, such as constant volume (CV), constant normal load (CNL) and constant normal stiffness (CNS) shear tests. Furthermore, model predictions are compared with experimental results of CNS shear tests in Toyoura sand-steel interfaces. Numerical simulations showed that the model captures very well the main features of the interface behaviour with different boundary conditions and interface roughnesses. Secondly, and finally the interface model is used to pile axial loading applications. Pile resistance is compute...
KSCE Journal of Civil Engineering, 2015
Deformation Characteristics of Geomaterials / Comportement Des Sols Et Des Roches Tendres, 2003
Near Surface Geoscience 2012 – 18th European Meeting of Environmental and Engineering Geophysics, 2012
Soil Dynamics and Earthquake Engineering, 2015
ABSTRACT The effect of ground stratification on the seismic response of circular tunnels is inves... more ABSTRACT The effect of ground stratification on the seismic response of circular tunnels is investigated, as most practice-oriented studies consider homogeneous ground. A finite element plain-strain model of a circular tunnel cross-section embedded in a two-layered ground is used to highlight the influence of stratification on the tunnel׳s seismic response. The layers interface was placed at the crown, centre and invert level.
Rock Mechanics and Geo-engineering in Volcanic Environments, 2010
Solid Mechanics and Its Applications, 2007
Near Surface 2010 - 16th EAGE European Meeting of Environmental and Engineering Geophysics, 2010
Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, 2009
Geotechnical Special Publication, 2009
ABSTRACT In the north-western region of Portugal residual soils from granite are dominant, with s... more ABSTRACT In the north-western region of Portugal residual soils from granite are dominant, with specific and complex characteristics, typical of "non-textbooks" materials. Current design practice of bored and driven piles in residual weathered formations is merely semi-empirical and based on bearing capacity analyses (in general, without settlement evaluation). Fully instrumented pile load tests are very much informative for the elaboration of correlations between load-deformation behaviour and in situ tests results, for establishing well-based design criteria. A thorough study was held in 2004 at the University of Porto, with the execution of an extensive site investigation and laboratory characterization tests, allowing good input parameters for a pile prediction event. This project, supported by 4 construction companies, made use of pile load tests, aiming to launch a class A prediction event, i.e., all the predictions were submitted before the conduction of static pile load tests. Three different kinds of piles were executed: bored piles with temporary casing, continuous flight augered, CFA, piles with circular section — nominal diameter phi600mm, and driven piles (square section, B=350mm). The piles were loaded axially to failure. The submitted predictions is resumed, revealing surprising overestimations in the bored piles capacities, while for the driven piles there was an underestimation of the gains due to pile installation effects (densification, etc.). In this paper a simple approach to quantify the locked-in toe residual loads will be addressed. Read More: http://ascelibrary.org/doi/abs/10.1061/41022%28336%293
Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, 2009
Journal of Mathematical Physics, 2011
RESUMO Os acessos rodoviários de ligação da Plataforma Logística de Lisboa Norte (PLLN) à Auto-es... more RESUMO Os acessos rodoviários de ligação da Plataforma Logística de Lisboa Norte (PLLN) à Auto-estrada do Norte e à Estrada Nacional 1 situam-se na bacia aluvionar da margem direita do Rio Tejo, sendo, por isso, muito condicionante para a concepção e dimensionamento das obras a elevada espessura das aluviões lodosas, que chega a atingir 34 m. Entre as várias soluções de tratamento do terreno de fundação preconizadas destaca-se a utilização de aterros de pré-carga, associados ou não a geodrenos verticais. No presente artigo descrevem-se os critérios e procedimentos de dimensionamento dos aterros de pré-carga associados a geodrenos (afastamento da malha de geodrenos, altura dos aterros, tempo de actuação das pré-cargas e a utilização de GeoLeca) para a aceleração do processo de consolidação na fase de construção, visando reduzir para valores toleráveis os assentamentos residuais durante a vida útil da obra.
Journal of Earthquake Engineering, May 2, 2012
The resonant-column test is known as the standard laboratory test to obtain the dynamic propertie... more The resonant-column test is known as the standard laboratory test to obtain the dynamic properties of soils. This test is performed on a cylindrical specimen subjected to a triaxial stress state while a harmonic force is applied and the output vibration is measured. There are other types of tests, which can be performed in the RC apparatus by the automation of the process. In this study, two tests were implemented: the first one uses a sine sweep signal (frequency increases with time); the second one uses sine signal at constant frequency, but the amplitude is modified until a strain level previously defined is obtained. The modulus and damping ratio are simultaneously found by the solution of a transcendental equation in complex variable, where the resonance condition is not necessary to obtain the dynamic properties. Tests carried allow to recognize the potentialities of the developed tests.
The aim of this paper is to present a newly implemented D interface model, compatible with the EC... more The aim of this paper is to present a newly implemented D interface model, compatible with the ECP elastoplastic soil model, and its interest in the comprehension of the load transfer mechanisms. The paper will be developed in two parts. First, the soil-structure interface modelling is focused. The general hypothesis of the model is presented and described. The Interface model is then first tested by modelling different soil-120 120structure interface characterization shear tests, such as constant volume (CV), constant normal load (CNL) and constant normal stiffness (CNS) shear tests. Furthermore, model predictions are compared with experimental results of CNS shear tests in Toyoura sand-steel interfaces. Numerical simulations showed that the model captures very well the main features of the interface behaviour with different boundary conditions and interface roughnesses. Secondly, and finally the interface model is used to pile axial loading applications. Pile resistance is compute...
KSCE Journal of Civil Engineering, 2015
Deformation Characteristics of Geomaterials / Comportement Des Sols Et Des Roches Tendres, 2003
Near Surface Geoscience 2012 – 18th European Meeting of Environmental and Engineering Geophysics, 2012
Soil Dynamics and Earthquake Engineering, 2015
ABSTRACT The effect of ground stratification on the seismic response of circular tunnels is inves... more ABSTRACT The effect of ground stratification on the seismic response of circular tunnels is investigated, as most practice-oriented studies consider homogeneous ground. A finite element plain-strain model of a circular tunnel cross-section embedded in a two-layered ground is used to highlight the influence of stratification on the tunnel׳s seismic response. The layers interface was placed at the crown, centre and invert level.
Rock Mechanics and Geo-engineering in Volcanic Environments, 2010
Solid Mechanics and Its Applications, 2007
Near Surface 2010 - 16th EAGE European Meeting of Environmental and Engineering Geophysics, 2010
Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, 2009
Geotechnical Special Publication, 2009
ABSTRACT In the north-western region of Portugal residual soils from granite are dominant, with s... more ABSTRACT In the north-western region of Portugal residual soils from granite are dominant, with specific and complex characteristics, typical of "non-textbooks" materials. Current design practice of bored and driven piles in residual weathered formations is merely semi-empirical and based on bearing capacity analyses (in general, without settlement evaluation). Fully instrumented pile load tests are very much informative for the elaboration of correlations between load-deformation behaviour and in situ tests results, for establishing well-based design criteria. A thorough study was held in 2004 at the University of Porto, with the execution of an extensive site investigation and laboratory characterization tests, allowing good input parameters for a pile prediction event. This project, supported by 4 construction companies, made use of pile load tests, aiming to launch a class A prediction event, i.e., all the predictions were submitted before the conduction of static pile load tests. Three different kinds of piles were executed: bored piles with temporary casing, continuous flight augered, CFA, piles with circular section — nominal diameter phi600mm, and driven piles (square section, B=350mm). The piles were loaded axially to failure. The submitted predictions is resumed, revealing surprising overestimations in the bored piles capacities, while for the driven piles there was an underestimation of the gains due to pile installation effects (densification, etc.). In this paper a simple approach to quantify the locked-in toe residual loads will be addressed. Read More: http://ascelibrary.org/doi/abs/10.1061/41022%28336%293
Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, 2009