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  • Numerical study of the influence of foundation compressibility and reinforcement stiffness on the behaviour of reinforced soil walls

     Puig Damians, Ivan; Bathurst, Richard; Josa Garcia-tornel, Alejandro; Lloret Morancho, Antonio
    International journal of geotechnical engineering
    Vol. 8, num. 3, p. 247-259
    DOI: 10.1179/1939787913Y.0000000039
    Date of publication: 2014-07-01
    Journal article

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    Most geosynthetic and metallic reinforced soil walls are designed assuming that the wall foundation is rigid and/or does not influence the magnitude and distribution of reinforcement loads under operational conditions. This assumption may not apply to walls constructed over compliant (compressible) foundations. This paper describes the results of a series of numerical simulations that were carried out on idealized 3·6, 6, and 9 m-high modular block walls seated on foundations having four different compressibility values. The walls were constructed with two reinforcement materials having very different stiffness values but the same tensile strength. The results of simulations show that as foundation stiffness decreases, reinforcement loads increase. However, for the two reinforcement materials in this study, the influence of axial stiffness of the reinforcement had a greater effect on wall performance than the foundation stiffness for walls subjected to operational (working stress) conditions at end of construction.

  • Numerical analysis of an instrumented steel reinforced soil wall

     Puig Damians, Ivan; Bathurst, Richard; Josa Garcia-tornel, Alejandro; Lloret Morancho, Antonio
    International journal of geomechanics
    p. 04014037-1-04014037-15
    DOI: 10.1061/(ASCE)GM.1943-5622.0000394
    Date of publication: 2014-02-20
    Journal article

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    The paper describes the results and lessons learned using a PLAXIS finite element method (FEM) model to simulate quantitative performance features of the Minnow Creek steel strip reinforced soil wall structure located in the USA. The Minnow Creek Wall structure was constructed and instrumented in 1999. It is a unique case study because of the comprehensive measurements that were taken to record a wide range of wall performance features. Two different constitutive models for the soil were used (linear-elastic Mohr-Coulomb and Hardening Soil model with Mohr-Coulomb failure criterion) and numerical outcomes compared with physical measurements. The numerical results were shown to be sensitive to boundary conditions assumed at the toe of the wall. The generally encouraging agreement between physical and numerically predicted results gives confidence that commercial FEM software packages can be useful for the analysis and design of these types of structures provided that care is taken in the selection of input parameters.

  • Deep enclosures versus pumping to reduce settlements during shaft excavations

     Pujades Garnes, Estanislao; Vázquez Suñé, Enric; Carrera Ramírez, Jesús; Vilarrasa Riaño, Victor; De Simone, Silvia; Jurado Elices, Anna; Ledesma Villalba, Alberto; Ramos Schneider, Gonzalo; Lloret Morancho, Antonio
    Engineering geology
    Vol. 169, p. 100-111
    DOI: 10.1016/j.enggeo.2013.11.017
    Date of publication: 2014-02-04
    Journal article

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    Deep excavations in aquifers may be constructed by combining pumping with the cut and cover method. The enclosures are often deepened more than structurally needed, in order to diminish the risk of heave or fluidisation inside the excavation, and to reduce pumping rates and the associated settlements outside jet-grouting piles are sometimes adopted for lengthening. We analysed the water-proofing efficiency of jet-grouting and the need for water isolation in preconsolidated sediments. We used data obtained from two shaft excavations during the construction of the high speed train tunnel in Barcelona, located adjacent to the Sagrada Familia Basilica. Jet-grouting was characterised using pumping tests before and after the construction of the enclosure. The effectiveness of deepened enclosures was evaluated by comparing settlements caused and discharges required for several dewatering scenarios. Differences between them lie in the depth of the enclosures. Settlements were calculated analytically, using the drawdown obtained from a hydrogeological model, and numerically employing a hydro-mechanical model. Results show that jet-grouting reduced the permeability of the soil (90% reduction, from 5.5 to 0.6 m/d). However, this reduction only affected the pile area, so that the necessary pumping rate and the settlements outside the enclosure were only reduced by 40%. Results also show that settlements due to groundwater pumping are fairly smooth (i.e., differential settlements are small) with low absolute values. Moreover, they recover when pumping ceases. This rather elastic and stiff behaviour reflects the preconsolidated nature of the sediments in Barcelona and the fact that drawdowns concentrate at depth, where the soil is most compact, causing little change in effective stress near the soil surface. Under these conditions, pumping does not pose a serious risk to settlements, and excavation costs can be lowered by constructing the enclosure at the minimum depth required structurally. Also, an intense control of the pumping process may help reducing the conventional safety factors against heave.

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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.

  • Thermo-hydraulic behaviour of the vadose zone in sulphide tailings at Iberian Pyrite Belt: waste characterization, monitoring and modelling

     Blanco, Alejandro; Lloret Morancho, Antonio; Carrera Ramírez, Jesús; Olivella Pastalle, Sebastian
    Engineering geology
    Vol. 165, p. 154-170
    DOI: 10.1016/j.enggeo.2013.05.022
    Date of publication: 2013-10
    Journal article

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    Unsaturated conditions favour the oxidation of sulphide minerals from mine wastes, which results in the release of contaminant products into groundwater. An abandoned high-sulphide impoundment in the Iberia Pyritic Belt, wherein tailings have undergone oxidation for more than 28. years, was investigated for hydrological purposes. The objective was to understand the interactions between those mining tailings and the atmosphere under natural semiarid conditions (wet and dry seasons, short intensive rain events and strong daily temperature differences during the dry season).After the deposition, the sequence of waste textures that results from the sedimentation process is strongly dependent on the distance to discharge point. The spatial continuity of the sedimentation layers was studied by means of small scale dynamic penetration tests.The thermo-hydraulic characterization of the waste includes the determination of the water retention curve, saturated and unsaturated permeability, pore size distribution and thermal properties for the different textures.Atmospheric and waste physical measures, from 2002 to 2006, were performed using different techniques. The important changes in the salinity of the waste avoided the use of a single calibration for the electromagnetic sensors; a valid alternative was the evaluation of the water content from thermal conductivity estimations.Finally, a numerical model using the HYDRUS-1D software is presented. Model results reasonably fit the in-situ measures of soil moisture, soil temperature, soil water potential and soil heat flux in the vadose zone of tailings impoundment. Moreover, they provide information for energy and water balance determinations.

  • One-dimensional cracking model in clayey soils

     Ávila1, G.E.; Ledesma Villalba, Alberto; Lloret Morancho, Antonio
    International Conference on Soil Mechanics and Geotechnical Engineering
    p. 1077-1080
    Presentation's date: 2013-09-04
    Presentation of work at congresses

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    It is difficult to formulate a general model to capture cracking initiation and evolution, because there are multiple factors that influence these processes. In order to simplify the evaluation and get more insight on the phenomenon, a series of shrinkage tests were performed inducing one-dimensional primary cracking on remolded clay from Bogotá. The results allowed the proposal of a conceptual model that, based on mould shape factor, initial moisture content and evaporation rate, may predict time for crack initiation and identify the location and direction of primary and secondary cracks. Results indicate that boundary conditions play a significant role in cracking evolution, due to the restrictions imposed to the free shrinkage and to the homogeneous evaporation rate. The moulds used for soil desiccation, allowed the induction of predefined cracks when their shape factor values were greater than 1.5. In these cases the model is simple and may be considered as a model of cracking with one degree of freedom. When moulds have a shape factor between 1 and 1.5, the degrees of freedom increase dramatically leading to much more complex crack patterns.

  • Influence of facing vertical stiffness on reinforced soil wall design

     Puig Damians, Ivan; Bathurst, Richard; Josa Garcia-tornel, Alejandro; Lloret Morancho, Antonio
    International Conference on Soil Mechanics and Geotechnical Engineering
    p. 1959-1962
    Presentation's date: 2013-09-02
    Presentation of work at congresses

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    Current design practices for reinforced soil walls typically ignore the influence of facing type and foundation compressibility on the magnitude and distribution of reinforcement loads in steel reinforced soil walls under operational conditions. In this paper, the effect of the facing vertical stiffness (due to elastomeric bearing pads placed in the horizontal joints between panels) on load capacity of steel reinforced soil walls is examined in a systematic manner using a numerical modelling approach. Numerical modelling was carried out using the commercial finite element program PLAXIS. The numerical model was verified against measurements recorded for an instrumented 6 m-high wall reinforced with steel strips. The influence of the facing stiffness and backfill-foundation stiffness combinations on the vertical load through the facing and on the magnitude and distribution of the reinforcement loads was examined. For walls subjected to operational (working stress) conditions at end of construction, the numerical results confirm that the vertical stiffness of the facing and soil-stiffness combinations can have a great effect on the vertical facing loads and on the magnitude and distribution of the load mobilized in the soil reinforcement layers.

  • Vertical-facing loads in steel reinforced soil walls

     Puig Damians, Ivan; Bathurst, Richard; Josa Garcia-tornel, Alejandro; Lloret Morancho, Antonio; Albuquerque, P.J.R.
    Journal of geotechnical and geoenvironmental engineering
    Vol. 139, num. 9, p. 1419-1432
    DOI: 10.1061/(ASCE)GT.1943-5606.0000874
    Date of publication: 2013-09
    Journal article

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    The paper investigates the influence of backfill soil, foundation soil, and horizontal joint vertical compressibility on the magnitude of vertical loads developed in steel-reinforced soil concrete panel retaining walls at the end of construction. Measurements of toe loads recorded from instrumented field walls are reviewed and demonstrate that vertical toe loads can be much larger than the self-weight of the facing. In extreme cases, these loads can result in panel-to-panel contact leading to concrete spalling at the front of the wall. Vertical loads in excess of panel self-weight have been ascribed to relative movement between the backfill soil and the panels that can develop panel-soil interface shear and downdrag loads at the connections between the panels and the steel-reinforcement elements. A two-dimensional finite-element model is developed to systematically investigate the influence of backfill soil, foundation soil, bearing pad stiffness, and panel-soil interaction on vertical loads in the panel facing. The results show that an appropriately selected number and type of compressible bearing pads can be effective in reducing vertical compression loads in these structures and at the same time ensure an acceptable vertical gap between concrete panels. The parametric analyses have been restricted to a single wall height (16.7 m) and embedment depth of 1.5 m, matching a well-documented field case. However, the observations reported in the paper are applicable to other similar structures. The general numerical approach can be used by engineers to optimize the design of the bearing pads for similar steel-reinforced soil wall structures using available commercial finite-element model packages together with simple constitutive models.

    The paper investigates the influence of backfill soil, foundation soil, and horizontal joint vertical compressibility on the magnitude of vertical loads developed in steel-reinforced soil concrete panel retaining walls at the end of construction. Measurements of toe loads recorded from instrumented field walls are reviewed and demonstrate that vertical toe loads can be much larger than the self-weight of the facing. In extreme cases, these loads can result in panel-to-panel contact leading to concrete spalling at the front of the wall. Vertical loads in excess of panel self-weight have been ascribed to relative movement between the backfill soil and the panels that can develop panel-soil interface shear and downdrag loads at the connections between the panels and the steel-reinforcement elements. A two-dimensional finite-element model is developed to systematically investigate the influence of backfill soil, foundation soil, bearing pad stiffness, and panel-soil interaction on vertical loads in the panel facing. The results show that an appropriately selected number and type of compressible bearing pads can be effective in reducing vertical compression loads in these structures and at the same time ensure an acceptable vertical gap between concrete panels. The parametric analyses have been restricted to a single wall height (16.7 m) and embedment depth of 1.5 m, matching a well-documented field case. However, the observations reported in the paper are applicable to other similar structures. The general numerical approach can be used by engineers to optimize the design of the bearing pads for similar steel-reinforced soil wall structures using available commercial finiteelement model packages together with simple constitutive models.

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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.

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    Modelling 3D mechanics interfaces with continuum elements  Open access

     Puig Damians, Ivan; Olivella Pastalle, Sebastian; Lloret Morancho, Antonio; Josa Garcia-tornel, Alejandro; Bathurst, Richard
    Workshop of CODE-BRIGHT Users
    p. 1-4
    Presentation's date: 2013-05-07
    Presentation of work at congresses

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    This document presents preliminary results of FEM-numerical analysis of soilreinforcement pullout tests. The numerical model has been developed with CODE_BRIGHT and assuming the interfaces as continuum materials. The results of the preliminary parametric analyses described herein provide useful information on the shear behavior modeling of soil-reinforcement strip interfaces under working stress conditions

    This document presents preliminary results of FEM-numerical analysis of soil-reinforcement pullout tests. The numerical model has been developed with CODE_BRIGHT and assuming the interfaces as continuum materials. The results of the preliminary parametric analyses described herein provide useful information on the shear behavior modeling of soil-reinforcement strip interfaces under working stress conditions.

  • 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.

  • Soil characterization and compressibility parameters of Bogota clay due to suction changes

     Ávila1, G.E.; Ledesma Villalba, Alberto; Lloret Morancho, Antonio
    Pan-American Conference on Unsaturated Soils
    p. 285-290
    Presentation's date: 2013-02
    Presentation of work at congresses

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    Parameters such as soil fabric, mineral composition, plasticity and grain size distribution together with soil-volume behavior are essential for the evaluation of shrinkage and cracking processes in soils. This paper presents the results of a laboratory testing program conducted on surface Bogota´ clay to evaluate basic geotechnical properties and compressibility soil parameters due to suction changes. Water retention curves and suction controlled oedometer tests, were used to evaluate the effects of suction changes. Calibration of suction imposed with Polyethylene Glycol of 35000 g/mol (PEG 35000) is presented here because it was only available for PEG 20000 and of lower molecular mass. Results show that the air entry value of the Bogota´ clay is high, that there is an important hysteretic behavior of the clay during drying and wetting cycles and that suction cycles produce a significant increase in the preconsolidation stress and in the stiffness parameters of the soil

  • 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.

  • Long-term experimental evidences of saturation of compacted bentonite under repository conditions

     Villar Galicia, María Victoria; Martín, Pedro Luís; Bárcena, I.; García Siñeriz, Jose Luis; Gomez Espina, R.; Lloret Morancho, Antonio
    Engineering geology
    Vol. 149-150, p. 57-69
    DOI: 10.1016/j.enggeo.2012.08.004
    Date of publication: 2012-11-02
    Journal article

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  • Influence of foundation compressibility on reinforcement loads in geosynthetic reinforced soil walls

     Bathurst, Richard; Puig Damians, Ivan; Ezzein, F.; Josa Garcia-tornel, Alejandro; Lloret Morancho, Antonio
    European Geosynthetics Congress
    p. 43-47
    Presentation's date: 2012-09-18
    Presentation of work at congresses

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    A numerical FLAC model was used to investigate the influence of vertical stiffness of the foundation on the performance of an idealized 6-m high reinforced soil modular block retaining wall. Three different Winkler linear spring values were used to simulate a rigid foundation and two compliant foundation cases. For each foundation condition, the influence of reinforcement material stiffness was also investigated. One material matched the properties of a relatively extensible polymeric geogrid product and the other a relatively inextensible welded wire mesh material with much higher stiffness but the same strength. The results of simulations show that as foundation stiffness decreases, reinforcement loads increase. However, for the two reinforcement materials in this study, the influence of axial stiffness of the reinforcement had a greater effect on wall performance than the foundation stiffness for walls subjected to operational (working stress) conditions at end of construction.

  • Water retention properties of a compacted clayey silt including void ratio dependency and microstructural features

     Gómez, Rodrigo; Romero Morales, Enrique Edgar; Della Cecchia, Gabriele; Jommi, Cristina; Suriol Castellvi, Jose; Lloret Morancho, Antonio
    European Conference on Unsaturated Soils
    p. 153-158
    Presentation's date: 2012-06
    Presentation of work at congresses

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    An experimental study focused on the water retention properties of a compacted clayey silt with dominant bimodal pore size distribution is reported. A water retention model accounting for soil microstructural features and void ratio is used to track the observed hydraulic behaviour. The model parameters were calibrated on the basis of drying and wetting data at a given dry density and the model predictions are verified along drying and wetting paths at different void ratios.

  • Effect of intermediate stress on collapse behaviour of a compacted clayey silt

     Cárdenas, Octavio; Romero Morales, Enrique Edgar; Lloret Morancho, Antonio; Suriol Castellvi, Jose
    European Conference on Unsaturated Soils
    p. 25-30
    Presentation's date: 2012-06
    Presentation of work at congresses

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    There are few experimental results on the influence of the intermediate principal stress on the behaviour of unsaturated soils. Particularly, the effect of intermediate stress on the collapse response of a soil subjected to a suction reduction path has not been studied in depth. This paper describes soaking tests performed in a hollow cylinder device, in which specimens of a compacted clayey silt have been saturated under constant mean and deviatoric stresses but at different intermediate stresses. The descriptions of sample preparation, testing device characteristics, test procedures and interpretation methods are presented. Preliminary analyses of the results seem to indicate that collapse is larger when the intermediate stress coincides with the minor one, i.e. under conventional axi-symmetric triaxial stress state.

  • Excavación de un pozo profundo para revisión de una tuneladora en el centro de Barcelona

     Ledesma Villalba, Alberto; Lloret Morancho, Antonio; de Santos, C.; Ramos, Gonzalo; Vázquez Suñé, Enric; Alonso Pérez de Agreda, Eduardo; Pujades Garnes, Estanislao; Carrera Ramírez, Jesús
    Simposio Nacional de Ingeniería Geotécnica
    p. 807-817
    Presentation's date: 2012
    Presentation of work at congresses

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  • Porosity variations in saline media induced by temperature gradients: experimental evidences and modelling

     Olivella Pastalle, Sebastian; Castagna, S.; Alonso Pérez de Agreda, Eduardo; Lloret Morancho, Antonio
    Transport in porous media
    Vol. 90, num. 3, p. 763-777
    DOI: 10.1007/s11242-011-9814-x
    Date of publication: 2011-12
    Journal article

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    Porosity variations in saline media containing humidity are induced by temperature gradients. A temperature imposed on a porous salt sample prepared with some brine and closed to mass transfer leads to significant variations of porosity in few weeks. Modelling of the experiments permits to understand the processes involved.

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    Análisis numérico de los esfuerzos verticales en el paramento de un muro de tierra reforzada en suelo diabásico  Open access

     Puig Damians, Ivan; Josa Garcia-tornel, Alejandro; Albuquerque, P.J.R.; Lloret Morancho, Antonio; Ledesma Villalba, Alberto; de Santos, C.
    Pan-Am CGS Geotechnical Conference. Pan-American Conference on Soil Mechanics and Geotechnical Engineering. Canadian Geotechnical Conference. Pan-American Conference on Teaching and Learning of Geotechnical Engineering
    p. 1-9
    Presentation's date: 2011-10-03
    Presentation of work at congresses

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    The paper presents a numerical analysis of the service behaviour of a reinforced soil wall constructed in a diabasic soil. A 2D model developed through the Finite Element Method (FEM) using the commercial computer software PLAXIS has been developed for this purpose. This model has been applied to the case of a 6 meters high wall constructed on a diabasic, lateritic and porous underlying soil, common to the region of Campinas (São Paulo, Brazil). The geotechnical properties of this soil have been quantified for different compaction levels. In particular the vertical stresses in the front structure of the wall have been analyzed. The results show that variations in the soil stiffness and of the structure elements geometry cause significant variations of the stress-strain state and the forces that are generated. Mediante el desarrollo de un modelo numérico 2D por el método de los elementos finitos (M.E.F.) con el programa comercial de ordenador PLAXIS se ha modelado el comportamiento en servicio de muros de tierra reforzada. Este modelo se ha aplicado al caso de un muro de 6 metros de altura ejecutado en suelo del diabásico, laterítico y poroso, común en la región de Campinas (São Paulo, Brasil), con propiedades resistentes variables que se han cuantificado según diferentes niveles de compactación. Utilizando este modelo se ha estudiado, en particular, el estado tensional en el paramento del muro. Los resultados más relevantes de dicho análisis, presentados en este documento, muestran que variaciones tanto en la rigidez del terreno como en la geometría de los elementos constructivos provocan cambios significativos en el estado tenso-deformacional y en de los esfuerzos que se generan.

  • Evaluation of alternative methodologies to minimize movements of a diaphragm wall close to buildings

     de Santos, C.; Ledesma Villalba, Alberto; Lloret Morancho, Antonio; Alonso Pérez de Agreda, Eduardo
    European Conference on Soil Mechanics and Geotechnical Engineering
    p. 1461-1466
    Presentation's date: 2011-09-13
    Presentation of work at congresses

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    In the framework of the construction of the high-speed railway passing through Barcelona, a large excavation (21m depth) has made to about 2 m of a building. The excavation was done in the quaternary material typical of the Barcelona plain which consists mainly of low plasticity and slightly cemented compact clays. This material due to its high stiffness can be considered as a "hard soil". In order to minimize movements, several methodologies were considered: change in the thickness of the diaphragm walls, increasing the length of the diaphragm walls and location of struts. The predictions of movements were performed using PLAXIS code, considering model parameters estimated from pressuremeter tests and resonant column. The smallest displacements were obtained if struts were placed in advance just below the maximum excavation level. Those struts had only 3 m thickness below the maximum excavation depth, and were built every 5.5 m in horizontal direction. The measured movements were somewhat lower than expected and the building suffered no damage. The paper demonstrates that struts below the maximum excavation level constitute a safe design when movements induced to buildings are a major concern.

  • Dynamics of water vapor flux and water separation processes during evaporation from a salty dry soil

     Gran Esforzado, Meritxell; MASSANA, JORDI; Carrera Ramírez, Jesús; Saaltink, Maarten Willem; Olivella Pastalle, Sebastian; Ayora Ibáñez, Carlos; Lloret Morancho, Antonio
    Journal of hydrology
    Vol. 396, num. 3-4, p. 215-220
    DOI: 10.1016/j.jhydrol.2010.11.011
    Date of publication: 2011-01
    Journal article

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    Evaporation from a salty soil generates salt accumulation near the surface with the subsequent deterioration of the soil quality. Salinization mechanisms are poorly understood despite their global impact. Vapor flux and solute transport were studied under evaporation conditions. Laboratory experiments consisted of open sand and silt columns initially saturated with epsomite (MgSO47H2O) or halite (NaCl) solutions. Salt precipitation occurred only above the evaporation front, which occupied a very narrow region. Vapor flowed both upwards and downwards from this front. The downward vapor flow condensed further down the column, diluting the solution. This gave rise to two areas: a high salinity area above the evaporation front, and a diluted solution area below it. The effects of thermal, suction and osmotic gradients on water fluxes were studied in order to better understand the underlying mechanisms of this phenomenon.

    Evaporation from a salty soil generates salt accumulation near the surface with the subsequent deterioration of the soil quality. Salinization mechanisms are poorly understood despite their global impact. Vapor flux and solute transport were studied under evaporation conditions. Laboratory experiments consisted of open sand and silt columns initially saturated with epsomite (MgSO4 7H2O) or halite (NaCl) solutions. Salt precipitation occurred only above the evaporation front, which occupied a very narrow region. Vapor flowed both upwards and downwards from this front. The downward vapor flow condensed further down the column, diluting the solution. This gave rise to two areas: a high salinity area above the evaporation front, and a diluted solution area below it. The effects of thermal, suction and osmotic gradients on water fluxes were studied in order to better understand the underlying mechanisms of this phenomenon.

  • Parameter calibration for hydro-mechanical modelling using numerical simulations of test results

     Gómez, Rodrigo; Romero Morales, Enrique Edgar; Lloret Morancho, Antonio; Suriol Castellvi, Jose; Jommi, Cristina
    International Conference on Unsaturated Soils
    p. 823-828
    Presentation's date: 2010-09-07
    Presentation of work at congresses

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    The paper reports an experimental study and parameter calibration exercise centred on the hydro-mechanical response of an unsaturated soil. The study benefits from compacted silt samples retrieved from a fully instrumented experimental embankment, which was built under poorly compacted conditions to study the collapse response upon artificial flooding. In addition to the hydraulic characterisation, the experimental programme includes controlled-suction tests intended to follow similar wetting and drying paths to those undergone by the material under real conditions. The suction dependent elastoplastic BBM model is used to simulate selected experimental results related to the collapsible behaviour (its time evolution and its response with decreasing suction). Mechanical and hydraulic parameters of the model are determined by both direct experimental procedures and numerical back analysis.

  • Numerical analysis of the behaviour of embankments constructed with expansive soils

     Ortega, J.J.; Lloret Morancho, Antonio; Olivella Pastalle, Sebastian; Romero Morales, Enrique Edgar
    International Conference on Unsaturated Soils
    p. 1331-1336
    Presentation's date: 2010-09
    Presentation of work at congresses

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    The recent advances made in modern Unsaturated Soil Mechanics have permitted the development of new analysis methods for the prediction of the behaviour of embankments and other earth structures subject to changes in atmospheric conditions (precipitation, temperature, relative humidity) and under the action of traffic loading. One of the breakthroughs of greatest interest is the possibility to numerically model the processes of volume change in expansive soils when subjected to variations in humidity. In this paper, the analysis employed, based upon the Barcelona Basic Model constitutive model (Alonso et al., 1990), to study the viability of the embankments of the speed railway Montornès del Vallès-La Roca del Vallès (LAV Madrid-Zaragoza-Barcelona-French Frontier), is presented. A coupled flux-deformation analysis has been undertaken to model the water-infiltration process through the embankment, and the associated volume change deformations have been evaluated in terms of rainstorm duration.

  • Direct measurement of thermal expansion in unsaturated soils

     Pintado, Xavier; Lloret Morancho, Antonio
    International Conference on Unsaturated Soils
    p. 593-596
    Presentation's date: 2010-09
    Presentation of work at congresses

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    A method designed to measure the thermal dilatation coefficient of unsaturated soils is presented. It is based on the ASTM 4535-85 standard with some important considerations taken into account. A number of tests following this methodology were performed on unsaturated swelling clay. Thermal dilatation coefficients were measured over a temperature range from 25 to 65°C for material dry densities and saturation degrees varying between 16–17 kN/m3 and 60–95%, respectively. The results are somewhat disperse, nevertheless, a clear trend with regard to temperature can be observed and thermal dilatation coefficient values can be extracted.

  • Effect of suction and plasticity on the shear strength of sand/silt mixtures

     Villar, Maria Victoria; Martín, Pedro Luís; Gómez-Espina, Ramón; Lloret Morancho, Antonio
    International Conference on Unsaturated Soils
    p. 391-396
    Presentation's date: 2010-09
    Presentation of work at congresses

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    This paper presents results of an experimental study on the effect of suction on the shear behaviour of sand/silt mixtures as determined with direct shear tests performed under suction control. The device used to perform these tests is a direct shear apparatus in which the shear box has been replaced by an air pressure chamber where matric suction can be applied by increasing the air pressure in the cell chamber while the water pressure at the bottom of the sample remains atmospheric (axis translation technique). The samples have been initially consolidated under constant normal stresses between 100 and 900 kPa for different matric suctions ranging from 0 to 1200 kPa. Afterwards, while the normal stress and the matric suction are kept constant, the samples have been sheared. The results obtained in the shear tests show the expected increase in strength with suction, particularly in cohesion, although the increase is less significant towards high suctions and for the high vertical stresses. In the range of stresses tested the relation between suction and cohesion is linear. The friction angle with respect to suction is lower than the internal friction angle, and decreases with the level of suction until reaching a constant, low value for the suctions corresponding to the residual zone of the water retention curve.

  • A coupled model for prediction of settlement and gas flow in MSW landfills

     Yu, Li; Batlle, F; Lloret Morancho, Antonio
    International journal for numerical and analytical methods in geomechanics
    Vol. 34, num. 11, p. 1169-1190
    DOI: 10.1002/nag.856
    Date of publication: 2010-08-15
    Journal article

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  • Multiphase flow and reactive transport model under very dry conditions

     Gran Esforzado, Meritxell; Carrera Ramirez, Jesus; Olivella Pastalle, Sebastian; MASSANA, JORDI; Saaltink, Maarten Willem; Ayora Ibáñez, Carlos; Lloret Morancho, Antonio
    International Conference on Computational Methods in Water Resources
    p. 1
    Presentation's date: 2010-06-21
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  • Saturation of compacted bentonite under repository conditions: long-term experimental evidences

     Villar, M.V.; García-Siñeriz, J.L.; Martín, P.L.; Lloret Morancho, Antonio; Bárcena, I.; Gómez-Espina, R.
    International Meeting on Clays in Natural and Engineered Barriers for Radioactive Waste Confinement
    p. 661-662
    Presentation's date: 2010-04-01
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  • Simulation of expansive clay behavior under simultaneous heating-hydration for nuclear waste storage applications

     Sánchez, Marcelo; Gens Sole, Antonio; Villar, M.V.; Lloret Morancho, Antonio
    GeoFlorida
    p. 1-10
    DOI: 10.1061/41095(365)44
    Presentation's date: 2010-02-22
    Presentation of work at congresses

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    The storage of nuclear waste is still an unresolved problem of the nuclear industry, being geological disposal the most favoured option. Most conceptual designs for the deep geological disposal of nuclear waste envisage placing the canisters containing the waste in horizontal drifts or vertical boreholes. The empty space surrounding the canisters is filled by an engineered barrier often made up of compacted swelling clay. A good understanding of thermo-hydro-mechanical (THM) issues is therefore necessary to ensure a correct performance of engineered barriers and seals. The conditions of the bentonite in a typical engineered barrier are being simulated in a mock-up heating test at almost scale. The evolution of the main Thermo-Hydro-Mechanical (THM) variables of this test are analyzed in this paper. Especial emphasis has been placed on the study of the effect of thermo-osmotic flow in the hydration of the clay barrier at advanced staged of the experiment.

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    Experimental investigation into temperature effect on hydro-mechanical behaviours of bentonite  Open access

     Villar, M. V.; Gómez-Espina, R.; Lloret Morancho, Antonio
    Journal of rock mechanics and geotechnical engineering
    Vol. 2, num. 1, p. 71-78
    DOI: 10.3724/SP.J.1235.2010.00071
    Date of publication: 2010
    Journal article

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    The bentonite barrier of underground repositories for high-level radioactive waste will be hydrated by the groundwater while it is subjected to high temperatures due to the radioactive decay of the wastes. These changes of temperature affect the hydraulic and mechanical responses of bentonite, which has important effects on design and performance of repositories. The temperature influence on the hydro-mechanical behaviour of bentonite was studied in this paper by experiments, which were carried out with the Spanish FEBEX bentonite compacted at dry densities expected in the repository (from 1.5 to 1.8 Mg/m3). The dependence of the swelling strains of bentonite on the temperature has been measured from 30 °C to 90 °C. At high temperatures the swelling capacity of clay slightly decreases. Also, a clear decrease of swelling pressure as a function of temperature was observed for the same dry densities. Nevertheless, the deformation of bentonite is more dependent on the stress than the temperature. An increase in the permeability of water saturated bentonite with temperature has also been detected. The water retention curves of bentonite compacted at different dry densities were determined under isochoric conditions and in the range of temperatures from 20 °C to 120 °C. For a given density and water content, the suction decreases as the temperature increases at a rate, which is larger than the one predicted on the basis of water surface tension changing with temperature. Mechanisms related to the physico-chemical interactions that take place at microscopic level, in particular the transfer of interlayer water to the macropores triggered by temperature, seem to explain qualitatively the experimental observations.

  • Célula de corte simple con actuador horizontal cíclido para ensayos de suelos

     Romero Morales, Enrique Edgar; Ledesma Villalba, Alberto; Lloret Morancho, Antonio; Carol Vilarasau, Ignacio; Alonso Pérez de Agreda, Eduardo
    Competitive project

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  • Modeling the transient behaviour of the FEBEX bentonite in swelling pressure test

     Sanchez, M.; Villar, M.V.; Gens Sole, Antonio; Lloret Morancho, Antonio
    International Meeting on Clays in Natural and Engineered Barriers for Radioactive Waste Confinement
    p. 729-730
    Presentation's date: 2010
    Presentation of work at congresses

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  • Characterising the collapsible response of an in-situ compacted silt

     Gómez, R.; Romero Morales, Enrique Edgar; Lloret Morancho, Antonio; Suriol Castellvi, Jose
    Asia Pacific Conference on Unsaturated Soils
    p. 371-376
    Presentation's date: 2010
    Presentation of work at congresses

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  • Microstructural modifications induced by hydraulic and mechanical actions on compacted bentonite

     Romero Morales, Enrique Edgar; Suriol Castellvi, Jose; Lloret Morancho, Antonio; Castellanos, Enrique; Villar, M.V.
    International Meeting on Clays in Natural and Engineered Barriers for Radioactive Waste Confinement
    p. 695-696
    Presentation's date: 2010
    Presentation of work at congresses

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    Salinity is reduced below the evaporation front during soil salinization  Open access

     Gran Esforzado, Meritxell; Carrera Ramirez, Jesus; Olivella Pastalle, Sebastian; MASSANA, JORDI; Saaltink, Maarten Willem; Ayora Ibáñez, Carlos; Lloret Morancho, Antonio
    Jornadas de Investigación de la Zona no Saturada del Suelo
    p. 1-7
    Presentation's date: 2009-11-18
    Presentation of work at congresses

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    La salinización de suelos es un problema global. Generalmente, la salinización es causada por el transporte de sales hacia la superficie por capilaridad y, a pesar de su importancia global, los mecanismos que la controlan aún no están bien descritos (Kampf et al., 2005). En este trabajo, se han llevado a cabo experimentos de laboratorio y simulaciones numéricas que muestran que las sales precipitan en el frente de evaporación, el cual se da en una zona estrecha del suelo y que el flujo de vapor de agua se desplaza, no solo en sentido ascendente, sino también descendente, desde dicho frente de evaporación. El flujo de vapor descendente, condensa, causando la dilución de la solución. Esto implica, que contrariamente a lo creído hasta ahora, la salinización (Xu y Shao, 2002) (la precipitación de sales) no se da por debajo del frente de evaporación. Soil salinzation is a global problem. Salinization is generally caused by salts transported to the soil surface by capillary rising water. Despite its global importance, actual salinization mechanisms are poorly understood (Kampf et al., 2005). We use laboratory experiments and numerical models to show that salt precipitates at the evaporation front, which occurs within a very narrow band. Part of the evaporating water diffuses downwards, where it condensates. This implies that, contrary to widely spread belief, salinization (Xu & Shao, 2002) (i.e. salt precipitation) does not occur below the evaporation front. Instead, the upflowing solution becomes diluted.

  • Effect of soil saturation changes on pressure on tunnel linings

     de Santos, C.; Ledesma Villalba, Alberto; Lloret Morancho, Antonio
    International Conference on Soil Mechanics and Geotechnical Engineering
    p. 1766-1769
    Presentation's date: 2009-10
    Presentation of work at congresses

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    It is well known that changes in soil degree of saturation have an important influence on mechanical soil properties. Decreasing suction in soil leads to an increase of specific weight and to a decrease of stiffness and strength. These mechanical changes may have an important influence on underground works, particularly on subsurface tunnels. In fact, decreasing soil cohesion due to saturation reduces arching effects above tunnels. Recent developments in unsaturated soil behaviour include numerical models coupling hydromechanical phenomena and considering elastoplastic constitutive laws. However, these techniques are seldom used in practical applications. This paper presents a methodology to compute stress and strain changes in a tunnel lining due to changes in soil saturation, using relatively conventional tools. The motivation of this work comes from a real case in Barcelona, where a Metro tunnel received an increment of loading due to loss of cohesion of upper layers after irrigation. The Finite Element programme “PLAXIS” was used. The paper concludes that the effect of soil saturation changes on underground structures can be assessed by using conventional Finite Element codes, if the variation of stiffness and strength with suction is previously known. The analyses presented in the paper show that changes in density and stiffness due to saturation have little influence on the stresses in the sidewalls of a subsurface tunnel. However, reduction of cohesion due to suction changes may reduce arching effects above the tunnel and would generate high stresses in the tunnel lining.

  • Gas flow to a vertical gas extraction well in deformable MSW landfills

     Yu, L; Batlle Pifarre, Francisco; Carrera Ramírez, Jesús; Lloret Morancho, Antonio
    Journal of hazardous materials
    Vol. 168, num. 2-3, p. 1404-1406
    Date of publication: 2009-09
    Journal article

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  • Study of water and heat flow in unsaturated porous materials: mine tailings exposed to weather conditions.

     Blanco Romero, Alejandro
    Department of Geotechnical Engineering and Geo-Sciences, Universitat Politècnica de Catalunya
    Theses

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  • GRUPO DE GEOTECNIA Y MECANICA DE MATERIALES

     Levatti, Hector Ulises; Carol Vilarasau, Ignacio; Olivella Pastalle, Sebastian; Lopez Garello, Carlos Maria; Gens Sole, Antonio; Vaunat, Jean; Prat Catalan, Pere; Lloret Morancho, Antonio; Rodriguez, Mariana; Butlanska, Joanna; Garitte, Benoit; Ramon Tarragona, Anna; Jacinto, Carlos Abel; Aliguer Piferrer, Ignasi; Yubero De Mateo, Maria Teresa; Romero Morales, Enrique Edgar; Gesto Beiroa, Jose Manuel; Tapias Camacho, Mauricio Alberto; Garolera Vinent, Daniel; Lakashmikhanta, Ramasesha; Ledesma Villalba, Alberto; Pineda Jimenez, Jubert Andrés; Arroyo Alvarez de Toledo, Marcos; Josa Garcia-tornel, Alejandro; Sanchez Carracedo, Fermin; Pinyol Puigmarti, Nuria Merce; De Santos Rodriguez, Cristian; Alonso Pérez de Agreda, Eduardo
    Competitive project

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  • Análisis del comportamiento de terraplenes conformados con materiales potencialmente expansivos

     Ortega, J.I.; Lloret Morancho, Antonio; Olivella Pastalle, Sebastian; Romero Morales, Enrique Edgar
    Jornadas Hispano-Portuguesas sobre Geotecnia en Infraestructuras Ferroviarias
    p. 1-9
    Presentation's date: 2009-06-25
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  • LIVING WITH LANDSLIDE RISK IN EUROPE:ASSESSMENT, EFFECTS OF GLOBAL CHANGE AND RISK MANAGEMENT STRATEGIES

     Hürlimann Ziegler, Marcel; Olivella Pastalle, Sebastian; Fabregas Canovas, Francisco Javier; Alonso Pérez de Agreda, Eduardo; Romero Morales, Enrique Edgar; Gili Ripoll, Jose Antonio; Ledesma Villalba, Alberto; Lloret Morancho, Antonio; Pinyol Puigmarti, Nuria Merce; Lantada Zarzosa, Nieves; Aguasca Sole, Alberto; Mallorqui Franquet, Jordi Joan; Baeza Adell, Cristina; Moya Sanchez, Jose; Corominas Dulcet, Jordi
    Competitive project

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  • A full-scale in situ heating test for high-level nuclear waste disposal: observations, analysis and interpretation

     Gens Sole, Antonio; Sanchez, M; Guimaraes, Ldn; Alonso Pérez de Agreda, Eduardo; Lloret Morancho, Antonio; Olivella Pastalle, Sebastian; Villar, Maria Victoria; Huertas, Fernando
    G¿otechnique
    Vol. 59, num. 4, p. 377-399
    DOI: 10.1680/geot.2009.59.4.377
    Date of publication: 2009-05
    Journal article

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  • Thermo-hydraulic characterisation of soft rock by means of heating pulse tests  awarded activity

     Muñoz, Juan Jorge; Alonso Pérez de Agreda, Eduardo; Lloret Morancho, Antonio
    G¿otechnique
    Vol. 59, num. 4, p. 293-306
    DOI: 10.1680/geot.2009.59.4.293
    Date of publication: 2009-05
    Journal article

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    Low-permeability clayey rocks, currently considered as suitable host rocks for high-level nuclear waste disposal, pose a challenge for the determination of thermal, hydraulic and mechanical properties. A thermo-hydraulic stainless steel cell, capable of testing undisturbed soil or rock cores 70 mm in diameter and 100 mm long, has been developed and used to identify thermal properties (conduction coefficient, heat capacity, thermal expansion), permeability (derived from gas and water tests) and swelling behaviour. The cell is operated in a constant-temperature bath. Miniature pore water pressure transducers and thermocouples are installed in different positions of the specimen. Strain gauges attached to a reduced-thickness ring section of the cell provide information for swelling pressure determinations. Temperature changes are applied by a thin heater centred in the axis of the specimen. A computer code was specifically written to perform and control experiments. Air permeability is determined by means of a pulse decay technique, whereas liquid permeability is directly interpreted at steady-state conditions. However, back-analysis of the complete measured response of the specimen (pore pressures, temperatures and swelling pressures) provides the best procedure for identifying properties. A testing protocol involving a sequence of undrained and drained heating tests has been developed to determine, in an ordered way, the thermal properties and the permeability. The procedure requires the concourse of a coupled thermo-hydro-mechanical code in order to simulate test results. The program CODE_BRIGHT, developed at UPC, was used for these purposes. The procedure was applied to the identification of the thermal properties of Opalinus clay shale.

    Geotechnical Research Medal, Institution of Civil Engineering (London)

  • Assessment of the use of the vapour equilibrium technique in controlled-suction tests

     Pintado Llurba, Xavier; Lloret Morancho, Antonio; Romero Morales, Enrique Edgar
    Canadian geotechnical journal
    Vol. 46, num. 4, p. 411-423
    DOI: 10.1139/T08-130
    Date of publication: 2009-04
    Journal article

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    This paper presents a study on suction control methodology using the vapour equilibrium technique. To reduce the time needed to reach equilibrium, humid air is forced to flow through the sample boundaries. An analysis of the physical process that occurs in the tested soil samples using a numerical approach is included. The test is numerically simulated and the key parameters of the process calibrated. A sensivity analysis of the unmeasured and variables is performed. It could be observed that forcing humid air to flow through the sample reduces the equalization time, but the results from the numerical simulations highlight that this flow must be carefully applied to avoid reaching, under steady-state conditions, a different suction than that whished for. When the circulation of air along the boundaries is slow, an increase in air velocity tends to increase the rate of suction changes in the sample. However, if the circulation of air increases over some limit, the flow conditions inside the soil control the development of process.

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    Reply to the discussion by Leong et al. on 'Assessment of the use of the vapour equilibrium technique in controlled-suction tests'  Open access

     Pintado, X; Lloret Morancho, Antonio; Romero Morales, Enrique Edgar
    Canadian geotechnical journal
    Vol. 46, num. 12, p. 1485-1486
    DOI: 10.1139/T09-131
    Date of publication: 2009
    Journal article

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  • ROTURA PROGRESIVA Y REACTIVACION DE GRANDES DESLIZAMIENTOS: ANALISIS, PREDICCION Y RIESGOS

     Corominas Dulcet, Jordi; Moya Sanchez, Jose; Baeza Adell, Cristina; Ledesma Villalba, Alberto; Lloret Morancho, Antonio; Olivella Pastalle, Sebastian; Suriol Castellvi, Jose; Mavrouli, Olga Christina; Martinez Bofill, Joan; Yerro Colom, Alba; Pineda Jimenez, Jubert Andrés; Pinyol Puigmarti, Nuria Merce; Iglesias Gonzalez, Ruben; Romero Morales, Enrique Edgar; Serri, Victor; Alonso Pérez de Agreda, Eduardo
    Competitive project

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  • Salinity is reduced below the Evaporation front during soil salinization

     Olivella Pastalle, Sebastian; Saaltink, Maarten Willem; Lloret Morancho, Antonio
    European Geosciences Union General Assembly
    p. 1
    Presentation of work at congresses

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  • Characterising the collapsible response of an in-situ compacted silt

     Gómez, R.; Romero Morales, Enrique Edgar; Lloret Morancho, Antonio; Suriol Castellvi, Jose
    Date of publication: 2009
    Book chapter

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    The analysis of the hydro-mechanical and microstructural behaviour of a natural collapsible silty clay is presented in this paper. The analysis allowed concluding that a conventional model can be applied for the levels of stress and deformations considered in the study without the need of the application of complex models, which consider hydro-mechanical coupling. The model used in this paper was the BBM, proposed by Alonso et al. (1990), which also allows simulating diverse behavioural features of collapsible soils. Furthermore, through the analyses, it was possible to validate the proposal of Futai(1997), which suggested different values of r and pc (soil parameters of the BBM), hence rectifying a problem in the original model, which made difficult the simulation of a maximum collapse value. Finally, experimental results were satisfactory simulated through the BBM model and with parameters in accordance with the proposal of Futai (1997).

  • Experimental results on the effect of temperature on the hydromechanical behaviour of bentonite

     Villar, M.V.; Gómez-Espina, R.; Lloret Morancho, Antonio
    International Symposium on Unsaturated Soils Mechanics and Deep Geological Disposal of Nuclear Waste
    p. 272-280
    Presentation's date: 2009
    Presentation of work at congresses

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