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  • Best Paper in the Landslides Journal

     Pinyol Puigmarti, Nuria Merce; Alonso Pérez de Agreda, Eduardo; Corominas Dulcet, Jordi; Moya Sanchez, Jose
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  • Geotechnical Research Medal 2014

     Pinyol Puigmarti, Nuria Merce; Alonso Pérez de Agreda, Eduardo; Gens Sole, Antonio
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  • Grupo de Geotecnia y Mecánica de Materiales

     Carol Vilarasau, Ignacio; Gens Sole, Antonio; Josa Garcia-tornel, Alejandro; Ledesma Villalba, Alberto; Lloret Morancho, Antonio; Olivella Pastalle, Sebastian; Prat Catalan, Pere; Romero Morales, Enrique Edgar; Vaunat, Jean; Lopez Garello, Carlos Maria; Arroyo Alvarez de Toledo, Marcos; Pinyol Puigmarti, Nuria Merce; Rodriguez Dono, Alfonso; Alonso Pérez de Agreda, Eduardo
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  • Mathematical modelling of slopes

     Alonso Pérez de Agreda, Eduardo; Pinyol Puigmarti, Nuria Merce; Yerro Colom, Alba
    Procedia Earth and Planetary Science
    Vol. 9, p. 64-73
    DOI: 10.1016/j.proeps.2014.06.002
    Date of publication: 2014
    Journal article

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    The paper discusses first the effect of rainfall on the stability of slopes and it focusses on the role of permeability. Existing or induced discontinuities are shown to have a remarkable effect on the slope safety. Also, the relevance of changes in hydraulic properties in weathered profiles is discussed through a real case. The performance of modern ¿Lagrangian particle¿ methods and their capabilities to deal with large displacements is presented. The cases solved refer to brittle materials, a common situation in overconsolidated high plasticity clays.

  • Small scale slope failure benchmark test: modelling and prediction

     Hoffmann Jauge, Christian; Meler, Nuria; Pinyol Puigmarti, Nuria Merce; Alonso Pérez de Agreda, Eduardo
    Procedia Earth and Planetary Science
    Vol. 9, p. 201-205
    DOI: 10.1016/j.proeps.2014.06.021
    Date of publication: 2014
    Journal article

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    A benchmark was designed with the aim of evaluating the capabilities of current modelling techniques and computational codes to reproduce slope failures. Laboratory tests and three instrumented small scale experiments of slopes initially unsaturated and subjected to a controlled rainfall up to failure were performed. The objective of the benchmark was to predict one of the slope failures knowing the rest of the data. The paper presents the modelling strategy and the results obtained using the finite element code Code_Bright and the Barcelona Basic Model as the constitutive model for the unsaturated soils.

  • Modelling swelling phenomena in Lilla tunnel

     Ramon Tarragona, Anna; Alonso Pérez de Agreda, Eduardo
    International Workshop on CRYStallization in POrous Media
    p. 47
    Presentation's date: 2014-06-13
    Presentation of work at congresses

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  • The Buen Pastor Cathedral in San Sebastián

     Gens Sole, Antonio; Alonso Pérez de Agreda, Eduardo; Jubany Casanovas, Jorge; Uzcanga, Luis
    Date of publication: 2013
    Book chapter

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    The construction of an underground car park required an excavation in sand under the water table adjacent to the cathedral of Buen Pastor in San Sebastián, Spain. Because of the close proximity of the cathedral and other buildings, control of ground movements was a paramount consideration in the design. Construction involved the use of diaphragm walls propped by the floor slabs using the top-down technique. A monitoring system was installed to control the performance of the excavation throughout. For water control during the excavation, the diaphragm walls reached an underlying low permeability silt layer. This decision required the adoption of special measures to connect hydraulically the foundation ground of the cathedral with the water levels prevailing in the outside area. Excavation was completed with very limited ground movements that caused no observable damage in the cathedral and other nearby structures. Piezometer records also proved that the installed hydraulic connection performed satisfactorily.

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    VIII Simposio Nacional sobre Taludes y Laderas Inestables: volumen 1  Open access

    Date of publication: 2013-06-11
    Book

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    En Junio de 2013 tiene lugar en Palma de Mallorca el VIII Simposio Nacional sobre Taludes y Laderas Inestables. Este Simposio se ha consolidado como un foro independiente, abierto y pluridisciplinar, con el objeto de difundir los conocimientos entre los miembros de las comunidades técnica y académica, entre los investigadores, presentar los avances recientes y fomentar la discusión entre técnicos y científicos que trabajan en este apasionante campo. En los últimos años, especialmente desde finales de 2008, se han producido en la Isla de Mallorca diversos desprendimientos y deslizamientos que han llamado poderosamente la atención por su número y dimensiones. El debate sobre la causa de esta anómala concentración de eventos, incluyendo la influencia del cambio climático, sigue abierto a día de hoy. La edición 2013 es una excelente oportunidad para conocer de primera mano los detalles de estos eventos, los reconocimientos y soluciones adoptadas, así como las enseñanzas extraídas. Como en anteriores ocasiones, el Simposio tiene además por objetivo la presentación y discusión de los progresos realizados en los diversos ámbitos temáticos.

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    VIII Simposio Nacional sobre Taludes y Laderas Inestables: volumen 2  Open access

    Date of publication: 2013-06
    Book

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    En Junio de 2013 tiene lugar en Palma de Mallorca el VIII Simposio Nacional sobre Taludes y Laderas Inestables. Este Simposio se ha consolidado como un foro independiente, abierto y pluridisciplinar, con el objeto de difundir los conocimientos entre los miembros de las comunidades técnica y académica, entre los investigadores, presentar los avances recientes y fomentar la discusión entre técnicos y científicos que trabajan en este apasionante campo. En los últimos años, especialmente desde finales de 2008, se han producido en la Isla de Mallorca diversos desprendimientos y deslizamientos que han llamado poderosamente la atención por su número y dimensiones. El debate sobre la causa de esta anómala concentración de eventos, incluyendo la influencia del cambio climático, sigue abierto a día de hoy. La edición 2013 es una excelente oportunidad para conocer de primera mano los detalles de estos eventos, los reconocimientos y soluciones adoptadas, así como las enseñanzas extraídas. Como en anteriores ocasiones, el Simposio tiene además por objetivo la presentación y discusión de los progresos realizados en los diversos ámbitos temáticos.

  • Access to the full text
    VIII Simposio Nacional sobre Taludes y Laderas Inestables: volumen 3  Open access

    Date of publication: 2013-06
    Book

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    En Junio de 2013 tiene lugar en Palma de Mallorca el VIII Simposio Nacional sobre Taludes y Laderas Inestables. Este Simposio se ha consolidado como un foro independiente, abierto y pluridisciplinar, con el objeto de difundir los conocimientos entre los miembros de las comunidades técnica y académica, entre los investigadores, presentar los avances recientes y fomentar la discusión entre técnicos y científicos que trabajan en este apasionante campo. En los últimos años, especialmente desde finales de 2008, se han producido en la Isla de Mallorca diversos desprendimientos y deslizamientos que han llamado poderosamente la atención por su número y dimensiones. El debate sobre la causa de esta anómala concentración de eventos, incluyendo la influencia del cambio climático, sigue abierto a día de hoy. La edición 2013 es una excelente oportunidad para conocer de primera mano los detalles de estos eventos, los reconocimientos y soluciones adoptadas, así como las enseñanzas extraídas. Como en anteriores ocasiones, el Simposio tiene además por objetivo la presentación y discusión de los progresos realizados en los diversos ámbitos temáticos.

  • Effect of loading and suction history on time dependent deformation of crushed granular aggregates

     Romero Morales, Enrique Edgar; Alvarado de Menéndez, Clara; Alonso Pérez de Agreda, Eduardo
    Springer Series in Geomechanics and Geoengineering
    p. 99-104
    DOI: 10.1007/978-3-642-32492-5_9
    Date of publication: 2013
    Journal article

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    The paper presents the results of an experimental investigation aimed at evaluating the time-dependent compressibility of a coarse crushed quartzitic slate, focusing on the effects of the previous loading and hydraulic history. Long-term and large diameter compression tests under oedometer conditions were performed at different relative humidity (total suctions) and vertical stresses but following different loading and hydraulic paths. A finding is that pre-compressing at increasing overconsolidation ratios or pre-soaking the crushed material at constant and elevated stresses leads to the progressive vanishing of long-term deformations.

  • Extreme expansive phenomena in anhydritic-gypsiferous claystone: the case of Lilla tunnel

     Alonso Pérez de Agreda, Eduardo; Berdugo de Moya, Ivan Rafael; Ramon Tarragona, Anna
    Géotechnique
    Vol. 63, num. 7, p. 584-612
    DOI: 10.1680/geot.12.P.143
    Date of publication: 2013-06-01
    Journal article

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    The paper describes the expansive phenomena affecting Lilla tunnel in Spain during construction and subsequent operation. The geology of the site and the performance of alternative support designs are described. Field observations are analysed to identify the causes of the observed swelling. It was found that long-term swelling in Lilla tunnel was the result of gypsum crystal growth in discontinuities. The phenomenon was a consequence of a few contributing factors: significant presence of anhydrite, existent or activated discontinuities, and the circulation of water. These conditions were present in the highly tectonised Tertiary claystone in Lilla. The original horseshoe cross-section was transformed into a circular one, and a reinforced concrete lining was built to resist swelling pressures. Long-term monitoring of the reinforced tunnel provided valuable data on the evolution of swelling pressures against the lining, and on the stresses developed in the resisting structure. The highly heterogeneous distribution of swelling pressures against the lining explains the low strains measured in reinforcement bars despite the very high maximum swelling pressures recorded.

  • A constitutive model for compacted expansive and bonded marls

     Cardoso, Rafaela; Alonso Pérez de Agreda, Eduardo; Maranha das Neves, E.
    Géotechnique
    Vol. 63, num. 13, p. 1116-1130
    DOI: 10.1680/geot.12.P.101
    Date of publication: 2013-05
    Journal article

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    This paper focuses on understanding the mechanical response of non-saturated compacted marls used to build some motorway embankments in Portugal. The compacted material consists of crushed marls, which can be assumed to be a set of fragments with relatively large dimensions. Experimental studies on the hydromechanical behaviour of this compacted, evolving material show that it behaves as a material in the transition between rockfill (when the fragments can be considered approximately intact) and a clayey soil (when a large number of fragments show strong physical disaggregation). Existing models for compacted rockfill and compacted clayey materials are not adequate to reproduce this complex behaviour. Constitutive models able to reproduce this behaviour are required for predicting the behaviour of earth structures such as these embankments. A model is proposed for the prediction of volumetric deformations for stress and strain boundary conditions corresponding to the oedometric test. It consists of an elasto-plastic unsaturated, double-structure, constitutive model in which the compacted material is assumed to be the macrostructure, and the microstructure is the fragment itself. Owing to the fundamental role of the loss of structure of the marl fragments in global behaviour, a constitutive equation for soft rocks is given, which includes a rule for bond loss depending on suction. Good results are obtained when the model is used to reproduce experimental tests performed on samples of compacted marls to which stress and suction cycles are applied. Other than the model proposed in this paper, attempts to reproduce the behaviour of compacted soft rocks are unknown.

  • Massive sulfate attack to cement-treated railway embankments

     Alonso Pérez de Agreda, Eduardo; Ramon Tarragona, Anna
    Géotechnique
    Vol. 63, num. 10, p. 857-870
    DOI: 10.1680/geot.SIP13.P.023
    Date of publication: 2013-03
    Journal article

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    Two access embankments to a railway bridge, having a maximum height of 18 m, experienced a continuous and severe heave shortly after construction. Vertical displacements reached 120 mm in a 2-year period. The embankments were designed, by including soil¿cement-treated transition wedges, to provide an increasingly rigid support as the trains approach the stiff bridge abutments. A grid of 10 m deep jet-grouting columns was also built, with the purpose of stabilising the embankments. Instead, a sustained swelling deformation, which extended to depths of 8¿10 m, was activated. The compacted soil was low-plasticity clayey material, with a variable percentage of gypsum. The embankments suffered a massive ettringite¿thaumasite attack, which was triggered by the simultaneous presence of cement, clay, sulfates and an external supply of water (rain). The paper describes the field extensometer and inclinometer records, the long-term laboratory tests performed, some mineralogical observations and the reactions leading to the growth of expansive crystals, and presents a model that simulates the measured heave. Forces acting against the bridge, which was seriously damaged, were estimated. Remedial measures include removal of the active upper zone of the embankments, and the construction in stages of slabs supporting the rails and founded on piles built on both sides of the embankments. The case is considered unique because of the magnitude of the reaction developed in the embankments, and its damaging action on the nearby bridge structure.

    Two access embankments to a railway bridge, having a maximum height of 18 m, experienced a continuous and severe heave shortly after construction. Vertical displacements reached 120 mm in a 2-year period. The embankments were designed, by including soil–cement-treated transition wedges, to provide an increasingly rigid support as the trains approach the stiff bridge abutments. A grid of 10 m deep jet-grouting columns was also built, with the purpose of stabilising the embankments. Instead, a sustained swelling deformation, which extended to depths of 8–10 m, was activated. The compacted soil was low-plasticity clayey material, with a variable percentage of gypsum. The embankments suffered a massive ettringite–thaumasite attack, which was triggered by the simultaneous presence of cement, clay, sulfates and an external supply of water (rain). The paper describes the field extensometer and inclinometer records, the long-term laboratory tests performed, some mineralogical observations and the reactions leading to the growth of expansive crystals, and presents a model that simulates the measured heave. Forces acting against the bridge, which was seriously damaged, were estimated. Remedial measures include removal of the active upper zone of the embankments, and the construction in stages of slabs supporting the rails and founded on piles built on both sides of the embankments. The case is considered unique because of the magnitude of the reaction developed in the embankments, and its damaging action on the nearby bridge structure.

  • Gas flow in anisotropic claystone: modelling triaxial experiments

     Arnedo Gaute, Diego; Alonso Pérez de Agreda, Eduardo; Olivella Pastalle, Sebastian
    International journal for numerical and analytical methods in geomechanics
    Vol. 37, num. 14, p. 2239-2256
    DOI: 10.1002/nag.2132
    Date of publication: 2013-10
    Journal article

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    Selected gas pulse tests on initially saturated claystone samples under isotropic confinement pressure are simulated using a 3D thermo-hydro-mechanical code. The constitutive model considers the hydro-mechanical anisotropy of argillaceous rocks. A cross-anisotropic linear elastic law is adopted for the mechanical behaviour. Elements for a proper modelling of gas flow along preferential paths include an embedded fracture permeability model. Rock permeability and its retention curve depend on strains through a fracture aperture. The hydraulic and mechanical behaviours have a common anisotropic structure. Small-scale heterogeneity is considered to enhance the initiation of flow through preferential paths, following the direction of the bedding planes. The numerical simulations were performed considering two different bedding orientations, parallel and normal to the imposed flow in the test. Simulations are in agreement with recorded upstream and downstream pressures in the tests. The evolution of fluid pressures, degree of saturation, element permeability and stress paths are presented for each case analysed. This information provides a good insight into the mechanisms of gas transport. Different flow patterns are obtained depending on bedding orientation, and the results provide an explanation for the results obtained in the tests.

  • Heave of a railway bridge: modelling gypsum crystal growth

     Ramon Tarragona, Anna; Alonso Pérez de Agreda, Eduardo
    Géotechnique
    Vol. 63, num. 9, p. 720-732
    DOI: 10.1680/geot.12.P.035
    Date of publication: 2013-01
    Journal article

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    The heave of the central pillars of a railway bridge, founded on large-diameter bored piles, is a consequence of gypsum crystal growth in an anhydritic claystone stratum underlying the tip of the piles. The heave mechanism is explained by the presence of circulating water in the fractured anhydritic level. The model developed to reproduce the observed phenomena integrates a set of balance equations that includes two soluble species (gypsum and anhydrite) in addition to the inert minerals, kinetic equations for dissolution and precipitation, mechanical equilibrium, and the effect of precipitated mass on induced volumetric strains. Model calculations are compared with measured long-term field records of heave. Most of the model parameters are physico-chemical constants, a positive feature that limits the effort to calibrate material constants. The model is capable of accurate mid-term heave prediction, and it also correctly includes the effect of building a surface embankment with the purpose of reducing the heave rate. A sensitivity study is reported to achieve a deeper insight into the phenomena, and to investigate the relevance of a few controlling parameters.

  • A constitutive law for rock joints considering the effects of suction and roughness on strength parameters

     Zandarín Iragorre, Maria Teresa; Alonso Pérez de Agreda, Eduardo; Olivella Pastalle, Sebastian
    International journal of rock mechanics and mining sciences (1997)
    Vol. 60, p. 333-344
    DOI: 10.1016/j.ijrmms.2012.12.007
    Date of publication: 2013-06
    Journal article

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    The paper describes a set of experiments aimed at investigating suction effects on the shear behaviour of rock discontinuities. The experimental investigation focused on the effects of suction on the mechanical behaviour of rock joints. Laboratory tests were performed in a direct shear cell equipped with suction control. Suction was imposed using a forced vapour convection circuit connected to the cell and controlled by an air pump. Artificial joints of Lilla claystone were prepared. Joint roughness of varying intensity was created by carving the surfaces in contact in such a manner that rock ridges of different tip angles were formed. These angles ranged from 0° (smooth joint) to 45° (very rough joint profile). The geometric profiles of the two surfaces in contact were initially positioned in a ¿matching¿ situation...

  • Heave of a railway bridge induced by gypsum crystal growth: field observations

     Alonso Pérez de Agreda, Eduardo; Ramon Tarragona, Anna
    Géotechnique
    Vol. 63, num. 9, p. 707-719
    DOI: 10.1680/geot.12.P.034
    Date of publication: 2013-07
    Journal article

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    The central pillars of a bridge belonging to a recently built high-speed railway line experienced an unexpected and continuous heave after the end of construction. Pillars were founded on 3 × 3 pile groups capped by a rigid slab. The tips of piles supporting the central pillars reached a hard Tertiary anhydritic claystone. Deep extensometers allowed the identification of an active layer, 12¿15 m thick, located below the pile tips. Observations in recovered cores suggest that the heave is induced by the growth of gypsum crystals in discontinuities of the anhydritic claystone. No heave was observed in gypsum-rich claystones located above the anhydritic layer. Gypsum crystal growth is associated with dissolution of anhydrite and subsequent precipitation from a super-saturated aqueous solution. Boreholes and pile construction allowed a hydraulic connection of upper aquifers and the lower anhydritic formation. This hypothesis explains the role of the bridge construction in the triggering of a dormant heave phenomenon. The heave rate has been reduced to a small value by the weight added by an embankment 33 m high, which partially fills the original valley.

    The central pillars of a bridge belonging to a recently built high-speed railway line experienced an unexpected and continuous heave after the end of construction. Pillars were founded on 3 × 3 pile groups capped by a rigid slab. The tips of piles supporting the central pillars reached a hard Tertiary anhydritic claystone. Deep extensometers allowed the identification of an active layer, 12–15 m thick, located below the pile tips. Observations in recovered cores suggest that the heave is induced by the growth of gypsum crystals in discontinuities of the anhydritic claystone. No heave was observed in gypsum-rich claystones located above the anhydritic layer. Gypsum crystal growth is associated with dissolution of anhydrite and subsequent precipitation from a super-saturated aqueous solution. Boreholes and pile construction allowed a hydraulic connection of upper aquifers and the lower anhydritic formation. This hypothesis explains the role of the bridge construction in the triggering of a dormant heave phenomenon. The heave rate has been reduced to a small value by the weight added by an embankment 33 m high, which partially fills the original valley.

  • Thermo-hydro-mechanical analysis for the simulation of rapid sliding process in a new and fast ring shear prototype

     Serri, Victor; Romero Morales, Enrique Edgar; Lloret Morancho, Antonio; Suriol Castellvi, Jose; Alonso Pérez de Agreda, Eduardo
    Italian Journal of Engineering Geology and Environment
    num. 13, p. 193-199
    DOI: 10.4408/IJEGE.2013-06.B-16
    Date of publication: 2013
    Journal article

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    Vajont was a case of an extremely fast landslide and efforts to clarify the failure have been mainly concentrated in providing a consistent explanation taking into account this characteristic feature. Particularly in the case of Vajont landslide, attention has been essentially focused on the shearing properties of the sliding surface. An accepted explanation for the velocity reached is the thermo-hydraulic-mechanical coupling under saturated conditions, which induces thermal dilation and effective stress reduction due to pore pressure build-up. Nevertheless, lack of in situ and experimental information has become one of the main drawbacks when trying to explain these coupled processes. In situ information is difficult to obtain since temperature and pore pressure development during these fast processes are impossible of being measured. To overcome this limitation, a new fast sliding prototype -emulating a ring shear apparatus- has been recently developed at the Universitat Politècnica de Catalunya (Spain). This prototype can reach relatively high speeds along the sliding surface (up to 30 km/h) under relatively high total vertical stresses (up to 3 MPa). Temperature and pore pressure changes can be locally measured with miniature transducers located close to the shear band. The design of this complex prototype requires the use of simulation-aided techniques, to help with the interpretation of the coupled processes, as well as to estimate the maximum temperature and pore pressure changes. A thermo-hydro-mechanical formulation, applied to the ring shear test, is proposed in the paper to study pore water pressure build up and dissipation in a sliding surface being heated by the frictional work induced by the motion. Particularly, the proposed model is applied to simulate the evolution of the shear strength along the sliding surface during a fast sliding process.

  • Environmental degradation of claystones

     Pineda Jimenez, Jubert Andrés; Alonso Pérez de Agreda, Eduardo; Romero Morales, Enrique Edgar
    Géotechnique
    Vol. 64, num. 1, p. 64-82
    DOI: 10.1680/geot.13.P.056
    Date of publication: 2013-11
    Journal article

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    The paper presents the results of a comprehensive experimental programme carried out to study the effects of relative humidity cycling on the degradation of argillaceous rocks. Lilla claystone, a low-porosity Tertiary rock, was used for this purpose. Four aspects were analysed: (a) the influence of the number of relative humidity cycles; (b) the amplitude of relative humidity cycles; (c) the stress level; and (d) the effects of using liquid water or vapour during wetting paths. The application of relative humidity cycles induced a progressive degradation of the rock in terms of accumulative irreversible volumetric swelling, irreversible reduction in rock stiffness, and tensile strength. The irreversible expansion increased with the amplitude of the relative humidity change. However, it reduced with increase of the confining pressure. This irreversible behaviour accelerated when liquid water was used during the wetting paths. Microstructural analysis has shown that the degradation pattern of Lilla claystone was associated mainly with fissuring, as a consequence of non-uniform deformations of the clayey matrix. This phenomenon leads to the opening of fissures at the weaker interfaces of the clayey matrix with detrital, non-active minerals. A damage law derived in terms of the accumulated volumetric irreversible strain has been proposed to represent the progressive loss in volumetric and shear stiffness as well as the tensile strength.

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    Influencia del desembalse en la estabilidad de una ladera: caso real  Open access

     Pinyol Puigmarti, Nuria Merce; Alonso Pérez de Agreda, Eduardo; Corominas Dulcet, Jordi; Moya Sanchez, Jose
    Simposio Nacional sobre Taludes y Laderas Inestables
    p. 326-336
    Presentation's date: 2013
    Presentation of work at congresses

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    Un aspecto crítico a controlar en la gestión de embalses es la velocidad de descenso de nivel de agua debido al riesgo de inestabilidades en las laderas que lo forman. Este artículo presenta el estudio realizado para conocer las causas del desarrollo de un gran deslizamiento en la ladera de un embalse. Para ello se realizó en primer lugar un reconocimiento geológico y geotécnico con el fin de definir la tipología del movimiento, su geometría y materiales involucrados mediante la realización de sondeos profundos y la instalación de inclinómetros y piezómetros. Se determinó que se trataba de la reactivación de un antiguo deslizamiento traslacional de 40 Mm3. Mediante la observación detallada de los testigos y la información proporcionada por las medidas inclinómetricas, se determinó la posición de la superficie de deslizamiento. Ésta se localizó en un estrato arcilloso de edad Garumniense y de alta plasticidad. Se analizaron en el laboratorio muestras extraídas de esta arcilla y se evaluaron sus propiedades geotécnicas. La causa más probable del movimiento se asignó al descenso rápido del nivel del embalse que alcanzó velocidades de 1.2 m/s. El análisis se realizó para una sección representativa y mediante un programa de elementos finitos capaz de resolver de forma acoplada la respuesta mecánica e hidráulica. Se modeló la variación del nivel del embalse durante los 4 años previos a la rotura. La distribución de presión de agua calculada, determinante en el análisis de estabilidad, se validó mediante la comparación de los resultados con los valores medidos en los piezómetros instalados alrededor de la superficie de deslizamiento después de la rotura.

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    Rotura plana diferida de un desmonte en pizarras paleozoica  Open access

     Alonso Pérez de Agreda, Eduardo; Tarrago, Dani; Romero Morales, Enrique Edgar
    Simposio Nacional sobre Taludes y Laderas Inestables
    p. 302-313
    Presentation's date: 2013-06
    Presentation of work at congresses

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    Durante la ejecución de la excavación de los desmontes para la construcción de una nueva biblioteca pública de la zona norte de Barcelona, se produjo una rotura en el macizo rocoso excavado: una pizarra paleozoica fuertemente tectonizada. En el artículo se destaca la escasa seguridad de la excavación frente a roturas planas a favor de los planos de foliación de la pizarra. Se presentan resultados de ensayos de corte sobre estos planos y su relleno de arcillas plásticas. Se discuten también las causas que provocaron la rotura diferida del talud, a pesar de que su baja seguridad calculada haría suponer una rotura inmediata. Se han descrito dos mecanismos posibles: la contribución de la succión a incrementar los parámetros de resistencia al corte de juntas y la generación de presiones intersticiales negativas durante la excavación. En relación con el primer mecanismo se presentan resultados experimentales recientes.

    En Junio de 2013 tiene lugar en Palma de Mallorca el VIII Simposio Nacional sobre Taludes y Laderas Inestables. Este Simposio se ha consolidado como un foro independiente, abierto y pluridisciplinar, con el objeto de difundir los conocimientos entre los miembros de las comunidades técnica y académica, entre los investigadores, presentar los avances recientes y fomentar la discusión entre técnicos y científicos que trabajan en este apasionante campo. En los últimos años, especialmente desde finales de 2008, se han producido en la Isla de Mallorca diversos desprendimientos y deslizamientos que han llamado poderosamente la atención por su número y dimensiones. El debate sobre la causa de esta anómala concentración de eventos, incluyendo la influencia del cambio climático, sigue abierto a día de hoy. La edición 2013 es una excelente oportunidad para conocer de primera mano los detalles de estos eventos, los reconocimientos y soluciones adoptadas, así como las enseñanzas extraídas. Como en anteriores ocasiones, el Simposio tiene además por objetivo la presentación y discusión de los progresos realizados en los diversos ámbitos temáticos.

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    Análisis de procesos termo-hidro-mecánicos en deslizamientos rápidos en un nuevo equipo de corte anular rápido  Open access

     Serri, Victor; Romero Morales, Enrique Edgar; Lloret Morancho, Antonio; Suriol Castellvi, Jose; Alonso Pérez de Agreda, Eduardo
    Simposio Nacional sobre Taludes y Laderas Inestables
    p. 1157-1166
    Presentation's date: 2013-06
    Presentation of work at congresses

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    Se ha desarrollado un nuevo corte anular para estudiar deslizamientos rápidos donde se induzca calentamiento por fricción. La generación de presiones intersticiales en la banda de corte calentada por el trabajo friccional del movimiento se ha aceptado como una explicación para las velocidades alcanzadas en deslizamientos rápidos. La falta de datos experimentales ha sido un inconveniente para analizar estos procesos acoplados. El prototipo, que incorpora un control electrónico del par impuesto y de la velocidad, puede alcanzar velocidades de deslizamiento elevadas (hasta 30 km/h) bajo tensiones vertical es relativamente grandes (hasta 3MPa). El diseño del prototipo y la selección de los transductores requieren de modelaciones numéricas previas para predecir la magnitud de las variables a medir. Esta publicación presenta una formulación acoplada, su solución numérica con una geometría simplificada para el equipo y los resultados obtenidos para la modelación de la presión de poros, temperatura y fuerza de corte.

    En Junio de 2013 tiene lugar en Palma de Mallorca el VIII Simposio Nacional sobre Taludes y Laderas Inestables. Este Simposio se ha consolidado como un foro independiente, abierto y pluridisciplinar, con el objeto de difundir los conocimientos entre los miembros de las comunidades técnica y académica, entre los investigadores, presentar los avances recientes y fomentar la discusión entre técnicos y científicos que trabajan en este apasionante campo. En los últimos años, especialmente desde finales de 2008, se han producido en la Isla de Mallorca diversos desprendimientos y deslizamientos que han llamado poderosamente la atención por su número y dimensiones. El debate sobre la causa de esta anómala concentración de eventos, incluyendo la influencia del cambio climático, sigue abierto a día de hoy. La edición 2013 es una excelente oportunidad para conocer de primera mano los detalles de estos eventos, los reconocimientos y soluciones adoptadas, así como las enseñanzas extraídas. Como en anteriores ocasiones, el Simposio tiene además por objetivo la presentación y discusión de los progresos realizados en los diversos ámbitos temáticos.

  • Microstructural evaluation of the water sensitivity of clayey rocks

     Pineda Jimenez, Jubert Andrés; Romero Morales, Enrique Edgar; Tarrago, Dani; Tauler Ferré, Esperança; Alonso Pérez de Agreda, Eduardo
    Biot Conference on Poromechanics
    p. 1454-1459
    DOI: 10.1061/9780784412992.173
    Presentation's date: 2013-07
    Presentation of work at congresses

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    The paper presents both macroscopic and microstructural evidence of the water sensitivity of a low porosity clayey rock from Northern Spain. Particular emphasis is focused on the effects of water sensitivity at micro level. Results obtained from Environmental Scanning Electron Microscopy (ESEM) using the common procedure of sample preparation show that this procedure of sample preparation is not enough to evaluate in a proper way the irreversible changes induced at micro level by hydraulic effects. An alternative procedure is described, which seems to improve the evaluation of rock degradation at micro scale.

  • Modelling crystal growth

     Ramon Tarragona, Anna; Alonso Pérez de Agreda, Eduardo
    Workshop of CODE-BRIGHT Users
    p. 1-4
    Presentation's date: 2013-05-07
    Presentation of work at congresses

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    The sustained heave of Pont de Candí Bridge is a consequence of the development of swelling strains in the sulphated claystone located below the tips of the foundation piles of the central pillan; of the bridge. The development of swelling phenomena in sulphated claystone is explained by the precipitation of gypsum crystals in fractures. A model has been formulated to describe the kinetics of precipitation and dissolution of sulphated minerals, the development of strains induced by crystallization and the solute transport. The heave of Pont de Candí Bridge has been modelled and calculations have been compared with the field measurements.

  • Thermo-hydro-mechanical analysis of rapid sliding process in a new and fast ring shear prototype

     Serri, Victor; Romero Morales, Enrique Edgar; Lloret Morancho, Antonio; Suriol Castellvi, Jose; Alonso Pérez de Agreda, Eduardo
    International Conference on Landslides' Risk
    p. 165-173
    Presentation's date: 2013-03
    Presentation of work at congresses

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    A new experimental apparatus -emulating the annular shape of the ring shear- has been designed and developed at the Universitat Politecnica de Catalunya to study fast sliding processes promoted by heat induced friction. This mechanism, which involves pore water pressu regeneration and dissipation in the shear band being heated by the frictional work of the sliding motion, has been an accepted explanation for the high velocity reached in the case of Vajont landslide. Nevertheless, lack of in situ and experimental information has become one of the main drawbacks when trying to explain these coupled processes . The prototype, which incorporates electronic control of torque and speed to emulate force and displacement control conditions, can reach high velocity along the sliding surface (up to 30 km/h and of the order of magnitude of the Vajont case) under relatively high total vertical stresses (up to 3 MPa). The design of this complex prototype and the selection of transducers require the use of simulation-aided techniq ues to help with the interpretation of these coupled thermo-hydro-mechanical processes. The paper presents the coupled formulation, the numerical solution adopted and the simplified geometry used for the equipment, as well as selected results of the pore pressure, temperature and shear strength evolutions along the sliding surface of a synthetic fast sliding test. These results are used to better know the location, range, sensitivity and fast response required for the temperature and pore pressure transducers, which are located close to the sliding surface.

  • Coupled hydro-chemo-mechanical modelling of a foundation heave due to gypsum crystal growth

     Ramon Tarragona, Anna; Alonso Pérez de Agreda, Eduardo
    Computational Methods for Coupled Problems in Science and Engineering
    p. 1-2
    Presentation's date: 2013-06-18
    Presentation of work at congresses

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  • Analysis of ettringite attack to stabilized railway bases and embankments

     Ramon Tarragona, Anna; Alonso Pérez de Agreda, Eduardo
    International Conference on Soil Mechanics and Geotechnical Engineering
    p. 785-788
    Presentation's date: 2013-09
    Presentation of work at congresses

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    Two cases of massive sulphate attack to cement treated embankments and track bases in a high speed railway line are described. In the first case, two large access embankments to a railway viaduct were treated with jet¿grouting columns. In the second case a compacted cement treated soil was placed over a rigid concrete caisson. The treated layer, 1.5 m thick, expanded at a continuous rate of 0.9-1.3 mm/month. In the two cases the soil was excavated from nearby cuts in gypsiferous Tertiary (Oligocene) claystones. Ettringite and thaumasite crystals were found within the expanding levels. The chemical evolution of an interface between a cement treated body and a compacted soil is presented. Solutions adopted to remediate the created problem are briefly described.

    Two cases of massive sulphate attack to cement treated embankments and track bases in a high speed railway line are described. In the first case, two large access embankments to a railway viaduct were treated with jet–grouting columns. In the second case a compacted cement treated soil was placed over a rigid concrete caisson. The treated layer, 1.5 m thick, expanded at a continuous rate of 0.9-1.3 mm/month. In the two cases the soil was excavated from nearby cuts in gypsiferous Tertiary (Oligocene) claystones. Ettringite and thaumasite crystals were found within the expanding levels. The chemical evolution of an interface between a cement treated body and a compacted soil is presented. Solutions adopted to remediate the created problem are briefly described.

  • Modelling swelling behavior of anhydritic clayey rocks

     Ramon Tarragona, Anna; Alonso Pérez de Agreda, Eduardo
    International Symposium on Computational Geomechanics
    p. 348-358
    Presentation's date: 2013-08-23
    Presentation of work at congresses

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    The swelling behavior observed in anhydritic rocks is explained by the precipitation of gypsum crystals in open discontinuities. Gypsum crystals growing in discontinuities contribute to open them and induce deformations or pressures (if the displacements are restrained). A model has been formulated to reproduce the expansive behavior in sulphated rocks. The formulation describes the kinetics of dissolution and precipitation of sulphated minerals and transforms the mass of precipitated gypsum to imposed swelling strains due to gypsum crystal growth. The model also keeps track of the solute transport and takes into account the effect of the existing load on crystal growth. A simulation of the heave observed in Pont de Candí Bridge is performed. The calculations reproduce the long term vertical displacements measured at the ground surface and the distribution of vertical strains measured in depth. A sensitivity analysis is also reported.

  • Modelación de deslizamientos con el Método del Punto Material

     Yerro Colom, Alba; Alonso Pérez de Agreda, Eduardo; Pinyol Puigmarti, Nuria Merce
    Congreso de Métodos Numéricos en Ingeniería
    p. 1
    Presentation's date: 2013-06-26
    Presentation of work at congresses

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  • A simplified procedure to assess the dynamic stability of a caisson breakwater

     Madrid, R.; Gens Sole, Antonio; Alonso Pérez de Agreda, Eduardo; Tarrago, Dani
    International Conference on Soil Mechanics and Geotechnical Engineering
    p. 2367-2370
    Presentation's date: 2013-09
    Presentation of work at congresses

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    The paper describes a simplified method of analysis used to evaluate the stability of a caisson breakwater to sea wave actions. An intensive laboratory program was performed in order to evaluate the static and dynamic characteristics of the foundation soil. Anisotropic and isotropic consolidated cyclic triaxial tests and cyclic simple shear tests were used to define the cyclic interaction diagram for the foundation soil. The possibility of foundation cyclic mobility due to wave loading and their effect on the breakwater stability was examined combining the cyclic interaction diagram with the results of finite element analysis. The potential reduction in soil strength is then incorporated into a conventional stability analysis. The procedure is illustrated by a specific application to a caisson breakwater that is part of the extension works of the Barcelona Harbour.

  • Effect of loading and suction history on time dependent deformation of coarse crushed slate

     Romero Morales, Enrique Edgar; Alvarado de Menendez, Clara; Alonso Pérez de Agreda, Eduardo
    Pan-American Conference on Unsaturated Soils
    p. 451-454
    Presentation's date: 2013-02
    Presentation of work at congresses

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    The paper presents the results of an experimental investigation aimed at evaluating the time-dependent compressibility of coarse crushed quartzitic slate, focusing on the effects of the previous loading and hydraulic history. Long-term and large diameter compression tests under oedometer conditions were performed at different total suctions (relative humidity values) and vertical stresses but following different loading and hydraulic paths. A finding, which has practical implications in earthwork constructions, is that pre-compressing at increasing overconsolidation ratios or pre-soaking the crushed material at constant and elevated stresses leads to the progressive vanishing of long-term deformations. 2013 Taylor Francis Group, London.

    The paper presents the results of an experimental investigation aimed at evaluating the time-dependent compressibility of coarse crushed quartzitic slate, focusing on the effects of the previ- ous loading and hydraulic history. Long-term and large diameter compression tests under oedometer conditions were performed at different total suctions (relative humidity values) and vertical stresses but following different loading and hydraulic paths. A finding, which has practical implications in earthwork constructions, is that pre-compressing at increasing overconsolidation ratios or pre-soaking the crushed material at constant and elevated stresses leads to the progressive vanishing of long-term deformations.

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    Thermo-hydro-mechanical analysis for the simulation of rapid sliding process in a new and fast ring shear prototype  Open access

     Serri, Victor; Romero Morales, Enrique Edgar; Lloret Morancho, Antonio; Suriol Castellvi, Jose; Alonso Pérez de Agreda, Eduardo
    International Conference on Vajont - 1963-2013
    p. 193-199
    DOI: 10.4408/IJEGE.2013-06.B-16
    Presentation's date: 2013-10-09
    Presentation of work at congresses

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    Vajont was a case of an extremely fast landslide and efforts to clarify the failure have been mainly concentrated in providing a consistent explanation taking into account this characteristic feature. Particularly in the case of Vajont landslide, attention has been essentially focused on the shearing properties of the sliding surface. An accepted explanation for the velocity reached is the thermo-hydraulic-mechanical coupling under saturated conditions, which induces thermal dilation and effective stress reduction due to pore pressure build-up. Nevertheless, lack of in situ and experimental information has become one of the main drawbacks when trying to explain these coupled processes. In situ information is difficult to obtain since temperature and pore pressure development during these fast processes are impossible of being measured. To overcome this limitation, a new fast sliding prototype -emulating a ring shear apparatus- has been recently developed at the Universitat Politècnica de Catalunya (Spain). This prototype can reach relatively high speeds along the sliding surface (up to 30 km/h) under relatively high total vertical stresses (up to 3 MPa). Temperature and pore pressure changes can be locally measured with miniature transducers located close to the shear band. The design of this complex prototype requires the use of simulation-aided techniques, to help with the interpretation of the coupled processes, as well as to estimate the maximum temperature and pore pressure changes. A thermo-hydro-mechanical formulation, applied to the ring shear test, is proposed in the paper to study pore water pressure build up and dissipation in a sliding surface being heated by the frictional work induced by the motion. Particularly, the proposed model is applied to simulate the evolution of the shear strength along the sliding surface during a fast sliding process.

  • Rockfill mechanics

     Oldecop, Luciano; Alonso Pérez de Agreda, Eduardo
    Pan-American Conference on Unsaturated Soils
    p. 61-86
    Presentation's date: 2013-02
    Presentation of work at congresses

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    The paper examines several aspects of rockfill behaviour, which are relevant to interpret and analyze the field response of dams and embankments. Experimental observations on rockfill compressibility, time-dependent deformation and deviatoric stress-strain behaviour are presented. Special attention is given to the role of relative humidity. The physics of rockfill deformation, explained by particle breakage are described. Particle breakage is explained by crack propagation, a phenomenon discussed within the framework of fracture mechanics. A macroscopic elastoplastic constitutive model is outlined. Rockfill mechanics are also approached by a Distinct Element modelling of grain assemblages experiencing grain breakage. Finally, rockfill mechanics are discussed from the wider perspective offered by unsaturated soil mechanics.

  • DEM modeling of unsaturated rockfill: scale effects

     Tapias Camacho, Mauricio Alberto; Alonso Pérez de Agreda, Eduardo; Gili Ripoll, Jose Antonio
    Pan-American Conference on Unsaturated Soils
    p. 455-460
    Presentation's date: 2013-02
    Presentation of work at congresses

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    The large size of the particles in rockfill structures prevents the appropriate laboratory testing. Moreover, the humidity is a key point to explain changes in the long term deformability of rockfill. Therefore, prediction of field behavior requires the development of models that integrate size effects and humidity changes. The Distinct Element Method has been used to develop a numerical model that includes assemblies of several spherical particles in a pyramidal shape. These "macroparticles" break when a rupture criterion involving the subcritical propagation of cracks within grain is achieved. This propagation is a function of stress state, defect size and relative humidity. Size effects for particles ranging from 0.28 to 56 cm of average diameter have been investigated. The results were validated against some real oedometer tests. The present work demonstrates the capabilities of the method as an useful tool to extend the laboratory tests on gravels to the actual rockfill dimensions

  • Rapid drawdown in embankment dams

     Pinyol Puigmarti, Nuria Merce; Alonso Pérez de Agreda, Eduardo; Olivella Pastalle, Sebastian
    DOI: 10.1201/b12130-1
    Date of publication: 2012
    Book chapter

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  • The Material Point Method and the analysis of dams and dam failures

     Zabala, Francisco; Alonso Pérez de Agreda, Eduardo
    DOI: 10.1201/b12130-1
    Date of publication: 2012
    Book chapter

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  • Environmental effects on earth embankments

     Olivella Pastalle, Sebastian; Alonso Pérez de Agreda, Eduardo
    DOI: 10.1201/b12130-1
    Date of publication: 2012
    Book chapter

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  • Swelling and degradation of argillaceous rocks induced by relative humidity effects: an experimental study

     Pineda Jimenez, Jubert Andrés
    Department of Geotechnical Engineering and Geo-Sciences, Universitat Politècnica de Catalunya
    Theses

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  • First Heim Lecture

     Alonso Pérez de Agreda, Eduardo
    Award or recognition

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  • Compacted soil behaviour: initial state, structure and constitutive modelling

     Alonso Pérez de Agreda, Eduardo; Pinyol Puigmarti, Nuria Merce; Gens Sole, Antonio
    Géotechnique
    Vol. 63, num. 6, p. 463-478
    DOI: 10.1680/geot.11.P.134
    Date of publication: 2012-11
    Journal article

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    The paper explores the behaviour of compacted soils throughout the (dry density-water content) compaction plane by means of a conceptual framework that incorporates microstructural information. The engineering properties of compacted soils are described by an initial state in terms of a yielding stress, soil suction and a microstructural state variable. Microstructure is defined by the ratio of microvoid volume to total void volume. The pattern of variation of the microstructural parameter within the compaction plane has been determined, for some compacted soils, by analysing mercury intrusion porosimetry data. The microstructure of wet and dry compaction conditions can then be quantified. To ensure consistency, the framework is cast in the form of a constitutive model defined in terms of an effective suction and a constitutive stress that incorporate the microstructural variable...

  • Crystal growth and geotechnics

     Alonso Pérez de Agreda, Eduardo
    Rivista italiana di geotecnica
    Vol. XLVI, num. 4, p. 13-56
    Date of publication: 2012
    Journal article

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  • Modelling the degradation and swelling of clayey rocks bearing calcium-sulphate

     Oldecop, Luciano; Alonso Pérez de Agreda, Eduardo
    International journal of rock mechanics and mining sciences
    Vol. 54, p. 90-102
    DOI: 10.1016/j.ijrmms.2012.05.027
    Date of publication: 2012
    Journal article

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  • Design of micropiles for tunnel face reinforcement: undrained upper bound solution

     Pinyol Puigmarti, Nuria Merce; Alonso Pérez de Agreda, Eduardo
    Journal of geotechnical and geoenvironmental engineering
    Vol. 138, num. 1, p. 89-99
    DOI: 10.1061/(ASCE)GT.1943-5606.0000562
    Date of publication: 2012-01
    Journal article

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    The stability of tunnel faces supported by an umbrella of subhorizontal micropiles is analyzed by means of the upper bound theorem of plasticity. The micropiles are considered beams subjected to the kinematic motion imposed by the assumed failure mechanism. The limiting resistance of the supporting beams is first addressed. The failure mechanism imposes a displacement pattern on the beam, which is similar to the response of vertical piles subjected to horizontal load. The mechanism of beam deformation was included into the overall instability mechanism for the tunnel face stability. Limiting conditions of the beam under undrained conditions are used. A general minimization process associated with the upper bound formulation is developed. Stability conditions are described in dimensionless parameters and plotted in ready-to-use design charts. In particular, a dimensionless micropile coefficient, which includes all the relevant design parameters of the umbrella, could be isolated and plotted in undrained soil strength and tunnel geometry. A real face failure is finally described, and the required supporting umbrella is designed on the basis of the developed procedure.

  • Canelles landslide: Modelling rapid drawdown and fast potential sliding

     Pinyol Puigmarti, Nuria Merce; Alonso Pérez de Agreda, Eduardo; Corominas Dulcet, Jordi; Moya Sanchez, Jose
    Landslides
    Vol. 95, num. 1, p. 33-51
    DOI: 10.1007/s10346-011-0264-x
    Date of publication: 2012-03
    Journal article

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  • Scale effects in rockfill behavior

     Alonso Pérez de Agreda, Eduardo; Tapias Camacho, Mauricio Alberto; Gili Ripoll, Jose Antonio
    Géotechnique Letters
    Vol. 2, num. 7-9, p. 155-160
    DOI: 10.1680/geolett.12.00025
    Date of publication: 2012-09
    Journal article

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  • Experimental behaviour of compacted marls

     Cardoso, Rafaela; Maranha das Neves, E.; Alonso Pérez de Agreda, Eduardo
    Géotechnique
    Vol. 62, num. 11, p. 999-1012
    DOI: 10.1680/geot.10.P.093
    Date of publication: 2012-08
    Journal article

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    Jurassic marls from Abadia, Portugal, were used in the construction of some motorway embankments. Large fragments of this evolving material remained after the construction process, and their degradation was of concern because of the expected change of the engineering properties of the compacted material. The material exhibits a very complex behaviour, which is difficult to reproduce with existing constitutive models for unsaturated structured materials. This paper focuses on understanding and providing data on the interaction between the pure marls (rock) and the aggregate behaviour. It presents the main results of tests performed to characterise the hydro-mechanical behaviour of compacted marls in specimens prepared with different grading size distributions and subjected to oedometer tests where both stress and suction changes were applied. The experimental data obtained were analysed, considering the presence of fragments and their degradation. The marl matrix was characterised to complete the existing data previously published for this material, but now with the purpose of providing a better explanation for the volumetric behaviour of the aggregate. The discussion is assisted by the explanation provided by a simple elasto-plastic model for unsaturated soils. Discrepancies with model predictions help to highlight the singularity of the marl aggregate. Compacted marls behave as materials in the transition between rockfill (when the fragments remain brittle) and a clayey soil (when the degradation accumulates). Therefore the compacted marl exhibits a dual behaviour. If it is dry, deformations are explained by the breakage of particles and rearrangement of the structure. If it is wet, the compacted marl is dominated by bond degradation of the material, the release of swelling potential and simultaneous changes in the stiffness and strength of the fragments. It appears that the transition from dry to wet can be identified by the current suction; moreover, it is rather abrupt.

  • Incorporating a microstructural state variable in constitutive modeling

     Pinyol Puigmarti, Nuria Merce; Alonso Pérez de Agreda, Eduardo; Gens Sole, Antonio
    Pan-American Conference on Unsaturated Soils
    p. 443-449
    Presentation's date: 2012-02
    Presentation of work at congresses

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    The selection of constitutive variables has been extensively discussed when modeling unsaturated soils. In general, suction and degree of saturation have been involved in the definition of constitutive variables. Recently, microstructural features have also been included due to their relevant effects on the mechanical and hydraulic soil response. This is the case of a model recently published by the same authors which includes a state variable in the definition of the constitutive variables to take into account microstructural effects. Details of the performance of this model, which has a relatively simple elastoplastic formulation, are presented. The simulation of isotropic stress paths illustrates the capabilities of the model and the effect of the microstructural state variable

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    Crystal growth under bridge foundations  Open access  awarded activity

     Ramon Tarragona, Anna; Alonso Pérez de Agreda, Eduardo
    International Workshop of Young Doctor in Geomechanics
    p. 61-66
    Presentation's date: 2012-11-21
    Presentation of work at congresses

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    A high-speed railway viaduct experienced a sustained heave at high rates after its construction. The pillars of the bridge are founded on an Eocene hard anhydritic-gypsiferous claystone by means of massive foundations. Field investigations identified an active layer below the piles¿ tips where expansions occur as a result of gypsum crystal growth in discontinuities from supersaturated aqueous solutions. The construction of the bridge is supposed to have triggered the swelling mechanism. An embankment, partially filling the valley, was built to slow the heave rate. The presence of soluble gypsum and anhydrite and inert materials is considered in the model developed to reproduce the observed expansive mechanism. The formulation describes the kinetics of dissolution and precipitation of minerals and the induced swelling strains by crystal growth. The calculated heave is compared with the field long-term vertical displacements measured before and after the construction of the embankment. A sensitivity study is also reported.

    A high-speed railway viaduct experienced a sustained heave at high rates after its construction. The pillars of the bridge are founded on an Eocene hard anhydritic-gypsiferous claystone by means of massive foundations. Field investigations identified an active layer below the piles’ tips where expansions occur as a result of gypsum crystal growth in discontinuities from supersaturated aqueous solutions. The construction of the bridge is supposed to have triggered the swelling mechanism. An embankment, partially filling the valley, was built to slow the heave rate. The presence of soluble gypsum and anhydrite and inert materials is considered in the model developed to reproduce the observed expansive mechanism. The formulation describes the kinetics of dissolution and precipitation of minerals and the induced swelling strains by crystal growth. The calculated heave is compared with the field long-term vertical displacements measured before and after the construction of the embankment. A sensitivity study is also reported.

    W(H)YDOC PhD Prize 2012, durant el 4th International Workshop of Young Doctors in Geomechanics W(H)YDOC 2012.

  • Preload improvement and monitoring in a newly reclaimed area

     Tarrago, Dani; Gens Sole, Antonio; Alonso Pérez de Agreda, Eduardo; Deu Lozano, Amadeu; Griell, R.
    International Conference on Ground Improvement and Ground Control
    p. 389-394
    Presentation's date: 2012-11
    Presentation of work at congresses

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    The paper describes the preload improvement of a newly reclaimed area that is part of the current development of the Barcelona Port. The area will provide the required surface of a new container terminal with a berth length of 1,600 m. The total surface area is 750,000 m2. The improvement affects both the hydraulic fill placed for the reclamation as well as the underlying soft natural ground. Improvement was required for both reducing subsequent settlements and providing an adequate level of stability during construction and quay commissioning. Special attention has been given to the reduction of the liquefaction potential of the hydraulic fill. The degree of improvement has been assessed comparing extensive site investigations performed before and after preloading. CPTu tests have proved especially useful in this regard. An extensive instrumentation scheme was deployed to observe the progress of preloading throughout the whole process. In some areas, preloading was supplemented by the installation of prefabricated vertical drains and by reinforcement using large-diameter gravel columns. The paper describes the ground improvement operations and the field monitoring observations performed during the works.