Sustainability of geosynthetics-based landslide stabilization solutions

This paper considers the sustainability of geosynthetics-based solutions to mitigate landslide risks. The different types of geosynthetics are briefly described, along with their functions and applications relevant to landslides, emphasizing reinforcement. The paper identifies the sustainability factors to consider when applying geosyn-thetics for these purposes. The paper then presents an overview based on existing literature to illustrate how geosynthetics typically outperform traditional methods across a range of sustainability criteria across the entire life cycle. The paper shows lastly how the value integrated model for sustainable evaluations (MIVES) tool can be applied to evaluate and compare alternative methods for remediation of landslides and recommends further studies using this tool.Peer ReviewedPostprint (published version

Fonction étanchéité et gestion des risques en contexte minier. IMPERMEABILITY AND RISK MANAGEMENT IN THE CONTEXT OF MINING ACTIVITIES

International audienceThe extractive industry generates waste that should be managed in such a way as to avoid generating risks for the environment and human health. Impermeability is an essential property for the efficient management of mining waste, especially for limiting the detrimental leakage to groundwater or surface water from tailings impoundments and other mining waste disposal sites, or to prevent the formation of acid mine drainage in the case of Sulfide-rich wastes. This paper presents a review of European and French legislation relative to mining waste management, of candidate materials for limiting infiltration and suggests recommendations with particular reference to the context of French Guyana.L'activité extractive génère des déchets qui doivent être gérés de manière à prévenir les risques pour l'environnement et la santé humaine. La fonction étanchéité est essentielle pour une bonne gestion des déchets miniers, notamment pour éviter que les parcs à résidus de traitement et autres installations de stockage de déchets ne génèrent des débits de fuite susceptibles de détériorer la qualité des eaux souterraines ou de surface, ou encore pour prévenir la formation de drainage minier acide dans le cas de déchets riches en sulfures. Cet article fait un point sur la réglementation européenne et française en matière de gestion des déchets de l'industrie extractive, passe en revue certains matériaux pouvant remplir cette fonction étanchéité et propose quelques recommandations avec une référence particulière au contexte minier guyanais

Numerical modelling of the nonlinear mechanical behavior of multilayer geosynthetic system for piggyback landfill expansions

Numerical modelling techniques have been increasingly used to assess the integrity of engineering works, such as landfills, that involve interactions between multiple geosynthetics GSYs). In piggyback landfill expansions (PBLEs), where a new landfill is built over an older one, such interactions are particularly important because multiple GSYs, natural materials, and waste interact with each over. To obtain reliable numerical results, the real mechanical behavior of the GSYs and of the interfaces between GSYs must be considered. Designers, however, often use simplistic assumptions without further analyzing the implications of these assumptions on the results. Such simplifications mainly concern the nonlinear axial stiffness of GSYs, the strain softening at interfaces between GSYs, and the difference between the compressive and tensile behavior of GSYs. By, considering these key aspects, the present study aims to understand the extent to which the results of numerical calculations can be influenced both by the differing compressive and tensile behavior of GSYs and by the assumption of strain softening at interfaces between GSYs. For this purpose, several numerical models are implemented by using the finite-difference code FLAC 2D on a typical PBLE that involves four GSYs and six interfaces. The present work also applies comprehensive, state-of-the-art numerical modelling to study the interactions between multiple layers of GSYs. This study also investigates the nonlinear axial stiffness of GSYs through a series of uniaxial tensile tests. The numerical results show that, if the GSY axial compressive and tensile characteristics are the same, then tensile force is minimized, which induces significant compressive force in the GSYs. The results also indicate that neglecting strain softening at the interface between GSYs affects interface shear stresses, displacements of GSYs at the interface, and the GSY force distribution, potentially rendering the model unrealistic. Including strain softening, however, allows the assessment (location) of unstable areas along the interface where large displacements occur

Numerical modeling of the nonlinear mechanical behavior of multilayer geosynthetic system for piggyback landfill expansions

This paper was accepted for publication in the journal Geotextiles and Geomembranes and the definitive published version is available at http://dx.doi.org/10.1016/j.geotexmem.2016.07.004.Numerical modelling techniques have been increasingly used to assess the integrity of engineering works, such as landfills, that involve interactions between multiple geosynthetics GSYs). In piggyback landfill expansions (PBLEs), where a new landfill is built over an older one, such interactions are particularly important because multiple GSYs, natural materials, and waste interact with each over. To obtain reliable numerical results, the real mechanical behavior of the GSYs and of the interfaces between GSYs must be considered. Designers, however, often use simplistic assumptions without further analyzing the implications of these assumptions on the results. Such simplifications mainly concern the nonlinear axial stiffness of GSYs, the strain softening at interfaces between GSYs, and the difference between the compressive and tensile behavior of GSYs. By, considering these key aspects, the present study aims to understand the extent to which the results of numerical calculations can be influenced both by the differing compressive and tensile behavior of GSYs and by the assumption of strain softening at interfaces between GSYs. For this purpose, several numerical models are implemented by using the finite-difference code FLAC 2D on a typical PBLE that involves four GSYs and six interfaces. The present work also applies comprehensive, state-of-the-art numerical modelling to study the interactions between multiple layers of GSYs. This study also investigates the nonlinear axial stiffness of GSYs through a series of uniaxial tensile tests. The numerical results show that, if the GSY axial compressive and tensile characteristics are the same, then tensile force is minimized, which induces significant compressive force in the GSYs. The results also indicate that neglecting strain softening at the interface between GSYs affects interface shear stresses, displacements of GSYs at the interface, and the GSY force distribution, potentially rendering the model unrealistic. Including strain softening, however, allows the assessment (location) of unstable areas along the interface where large displacements occur

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Vers une durabilité accrue des géomembranes bitumineuses

Depuis une trentaine d'années, les géomembranes sont largement employées dans les ouvrages hydrauliques, notamment pour assurer leur étanchéité. Dans un souci de préservation de l'environnement, il est donc essentiel de mieux connaître la durabilité de ces produits, afin d'optimiser leur conception et leur utilisation. Ici, il est question d'évaluer la performance de deux familles de géomembranes bitumineuses, l’une en bitume élastomère et l’autre en bitume oxydé, installées dans le même bassin depuis quinze ans. Les résultats permettront de fournir des préconisations d'utilisation essentielles pour les producteurs et les exploitants d’ouvrages

The role of geosynthetics in sustainable development and the circular economy

International audienc

The role of geosynthetics in sustainable development and the circular economy

International audienc

Contribution des géosynthétiques au développement durable

Il ne semble pas y avoir consensus pour dire si le monde traverse aujourd’hui une crise sans précédent ou non. Quoi qu’il en soit, il reste un nombre de situations inacceptables et des améliorations urgentes sont à réaliser. Le monde est un organisme complexe qui souffre de nombreuses crises : crise économique et financière, crise environnementale, de l’agriculture, crise sanitaire, crise des valeurs. Face à une crise systémique comme celle-ci la réponse doit être globale. Comment les géosynthétiques et la société internationale des géosynthétiques (International Geosynthetics Society, IGS) peuvent-ils contribuer à résoudre ces crises et apporter leur contribution à la guérison du monde ? Les solutions technologiques sont le plus souvent mises en exergue. Elles ne seront pas suffisantes. Quelles valeurs pouvons-nous attendre de l’IGS 35 ans après sa création ? L’objectif de la lecture Giroud, dans une version en français et raccourcie ici est de mettre en évidence ces différentes contributions pour apporter de l’eau de qualité à tous, nourrir le monde, protéger notre environnement, atténuer ou anticiper les catastrophes naturelles, apporter des solutions économiques et connecter les hommes pour les aider à vivre ensemble selon les valeurs humaines universelles

Performance of geosynthetics for environmental protection in landfills

International audienceThe objective of this Keynote Lecture is to give an updated overview of transfer properties of geosynthetic liner materials used in landfills and of parameters that impact them. Some innovative measurement techniques are detailed, especially as regards the measurement of advective flow rates for multicomponent geosynthetic clay liners GCLs. The measurement of advective flow rates through geomembranes and multicomponent GCLs is first described. Then the effect of the mass per unit area of bentonite in GCLs, the nature of the bentonite in GCLs and of hydration without load on the hydraulic conductivity of GCLs are described. A brief presentation of pollutants of concern in landfills and especially of microorganic pollutants is given. The chemical compatibility of GCLs with leachate is discussed in the third section of this Keynote Lecture. Finally, the diffusion of organic and inorganic species in relation with the composition of leachate previously described is given in the last section of this Keynote Lecture