276 results on '"pente"'
Search Results
2. Influence of competition on root architecture and root anchorage of young hybrid poplar plantations on waste rock slopes.
- Author
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Babi, Khadija, Guittonny, Marie, Bussière, Bruno, and Larocque, Guy R.
- Subjects
ARCHITECTURE competitions ,ROCK slopes ,REVEGETATION ,POPLARS ,HERBACEOUS plants ,ANCHORAGE - Abstract
Copyright of Ecoscience (Ecoscience) is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
- Full Text
- View/download PDF
3. The effects of an increased step frequency on running economy and injury risk factors during downhill running.
- Author
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Dewolf, A.H., Mesquita, R.M., and De Jaeger, D.
- Subjects
- *
DOWNHILL skiing , *SLOPES (Physical geography) - Published
- 2022
- Full Text
- View/download PDF
4. NEW THEORETICAL CONSIDERATIONS ON THE GRADUALLY VARIED FLOW IN A WIDE RECTANGULAR CHANNEL.
- Author
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B., ACHOUR and L., AMARA
- Subjects
HYDRAULIC engineering ,BACKWATER ,DIFFERENTIAL equations ,CHANNEL flow - Abstract
Copyright of Larhyss Journal is the property of Biskra University, Research Laboratory in Subterranean & Surface Hydraulics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
5. NEW THEORETICAL CONSIDERATIONS ON THE CRITICAL FLOW IN A CIRCULAR CONDUIT (PART 2).
- Author
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B., ACHOUR and L., AMARA
- Subjects
DIAMETER - Abstract
Copyright of Larhyss Journal is the property of Biskra University, Research Laboratory in Subterranean & Surface Hydraulics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
6. CRITICAL FLOW IN A TRIANGULAR-SHAPED CHANNEL.
- Author
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B., ACHOUR and L., AMARA
- Subjects
CHANNEL flow ,KINEMATIC viscosity ,HYDRAULICS ,CUBIC equations ,TRIGONOMETRY - Abstract
Copyright of Larhyss Journal is the property of Biskra University, Research Laboratory in Subterranean & Surface Hydraulics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
7. NEW THEORETICAL CONSIDERATIONS ON THE CRITICAL FLOW IN A CIRCULAR CONDUIT (PART 1).
- Author
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B., ACHOUR and L., AMARA
- Subjects
DIAMETER ,EQUATIONS - Abstract
Copyright of Larhyss Journal is the property of Biskra University, Research Laboratory in Subterranean & Surface Hydraulics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
8. Hillside urbanism in several cities around the world: Mexico City case study, (Mexico)
- Author
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Rivera González, Oscar Daniel and Rivera González, Oscar Daniel
- Abstract
The present research arises from the current problem of hillside urbanism in Mexico City (CDMX), established on river walls, mountain slopes and volcanic foothills, generating the risk of landslides, mainly caused by rains and earthquakes. It is important to emphasize that such hillside urbanism is minimally known worldwide, growing in other states of the Mexican Republic and in several countries. As a result, a comparison of various hillside urbanisms in the world differentiated with Mexico is established, contrasting information provided by the government and results obtained from Geographic Information Systems (GIS). Therefore, the objective of choosing the Mexico City as a sample is to contain the growth of hillside urbanism in other parts of Mexico and the world, based on urban restructuring plans through management between authorities and population., La presente investigación surge de la problemática actual del urbanismo de ladera en la Ciudad de México, establecido en paredes de ríos, laderas de montañas y en faldas de volcanes, generando riesgo de deslizamientos de ladera potencializados mayormente por lluvias y sismos. Es importante recalcar que dicho urbanismo de ladera es mínimamente conocido a nivel mundial, creciente en otros estados de la república mexicana y en diversos países. Como resultado se establece la comparación de diversos urbanismos de ladera en el mundo diferenciados con México, realizando contraste de información que otorga el gobierno y resultados obtenidos de Sistemas de Información Geográfica (SIG). Por lo anterior, el objetivo de elegir a la Ciudad de México como muestra es para contener el crecimiento de urbanismo de ladera en otras partes de México y del mundo, con base en planes de reestructuración urbana por medio de gestión entre autoridades y población., Cette recherche découle du problème actuel de l'urbanisme des collines de la ville de Mexico (CDMX), établi sur les murs des rivières, les pentes des montagnes et les contreforts volcaniques, générant le risque de glissements de terrain, principalement causés par les précipitations et les tremblements de terre. Il est important de souligner que ce type d'urbanisme à flanc de colline est peu connu dans le monde, se développant dans d'autres États de la République mexicaine et dans divers pays. Il en résulte une comparaison de divers urbanismes de collines dans le monde, différenciés du Mexique, en contrastant les informations fournies par le gouvernement et les résultats obtenus par les systèmes d'information géographique (SIG). Par conséquent, l'objectif du choix du la ville de Mexico comme échantillon est de contenir la croissance de l'urbanisme des collines dans d'autres régions du Mexique et du monde, sur la base de plans de restructuration urbaine par la gestion entre les autorités et la population.
- Published
- 2023
9. Factor of safety of slope stability from deformation energy.
- Author
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Xiao, Shiguo, Guo, Wei Dong, and Zeng, Jinxiu
- Subjects
SAFETY factor in engineering ,SLOPE stability ,SLOPES (Soil mechanics) ,DEFORMATIONS (Mechanics) ,ENERGY measurement ,MATHEMATICAL models - Abstract
Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2018
- Full Text
- View/download PDF
10. Site and tree factors determining the distribution of Phellinus tremulae in Populus tremuloides in Utah, USA.
- Author
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Koide, Roger T., Watkins, John, Ricks, Kevin, Aranda, Emily, Nettles, Rachel M., Yokum, Hannah, Yin, Na, and Clark, Eliza
- Subjects
- *
POPULUS tremuloides , *BUTT rots , *LOGISTIC regression analysis - Abstract
Populus tremuloides Michx. is an iconic tree of the mountains of the western United States. In Utah, it very commonly suffers from white trunk rot caused by Phellinus tremulae (Bondartsev) Bondartsev & P.N.Borisov. The incidence of this disease is affected by tree and site characteristics, but the magnitude of these effects appears to be site-dependent. To minimize harvest wood loss in Utah, we determined the locally important factors that explain the wide variation in the incidence of sporocarps of Phellinus tremulae. To avoid confounding of factors, we utilized a multiple regression approach. We found that while the incidence of Phellinus tremulae sporocarps on quaking aspen was always low at high elevations, it was variable at low elevations. Our logistic regression model indicated that variation in the incidence of sporocarps at low elevations was attributable, in part, to variation in aspect, slope, environmental stress, and tree age and size. Based on these results, we recommend that harvesting at elevations below 2500 m be confined to younger trees or to sites on relatively steep, north-facing slopes. Because of site-dependency, the same general method could be used to establish harvesting criteria in other regions. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
11. NEW APPROCH FOR THE NORMAL DEPTH COMPUTATION IN A TRAPEZOIDAL OPEN CHANNEL USING THE ROUGH MODEL METHOD.
- Author
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M., LAKEHAL and B., ACHOUR
- Subjects
BATHYMETRY ,HYDRAULICS ,SURFACE roughness - Abstract
Copyright of Larhyss Journal is the property of Biskra University, Research Laboratory in Subterranean & Surface Hydraulics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
12. Franchir les montagnes du Massif central à l’époque romaine. Sources antiques et données archéologiques
- Author
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Dacko, Marion
- Subjects
chaussées carrossables ,viae militares ,Roulage ,trafic ,pente ,viabilité hivernale ,travaux de construction et d’entretien routiers ,gradient ,Rolling ,traffic ,winter road maintenance ,road work and road maintenance ,public thoroughfare - Abstract
Several textual sources, whether military accounts or epistolary works inform us about road journeys in the mountain areas of the Massif central from the end of the La Tène period to late Antiquity. The passage of legions and official journeys or trips on foot or horseback on the various types of routes of communication in the sector (roads, tracks and pathways) are described as uncomfortable, laborious and even dangerous. Alongside this body of literary sources, movement through the Massif central in Roman times is documented by way of archaeological data from topographic sectors similar to those depicted in the accounts of Antiquity and forming part of mid-altitude mountain ranges. The handful of case studies collected in the context of this contribution relate to the chaîne des Puys, Haute-Combraille and the massif du Devès, which are still today thought of as difficult transit, À l’époque romaine, le Massif central est décrit par les sources textuelles comme un secteur délicat en termes de circulation routière. Dans cette région où les zones montagneuses couvrent les quatre cinquièmes de la superficie du territoire, la chaîne des Puys, la Haute-Combraille et le massif du Devès sont aujourd’hui encore considérés comme des points de passage difficiles. Traversés par des axes antiques de moyen et long parcours, ces trois espaces offrent de fortes contraintes climatiques (couverture neigeuse, vents vigoureux, cycles de gel et dégel) et topographiques (pentes, dénivellations) qui devaient considérablement peser sur la viabilité, notamment hivernale. Cette contribution propose de s’intéresser à la qualité des infrastructures de transport et à la gestion du trafic routier dans ces zones de relief., Dacko Marion. Franchir les montagnes du Massif central à l’époque romaine. Sources antiques et données archéologiques. In: Aquitania : une revue inter-régionale d'archéologie, tome 37, 2021. Tracer la route. Journée d’étude du 27 février 2020 à Bordeaux. pp. 103-115.
- Published
- 2021
13. DIMENSIONNEMENT D'UN CANAL OUVERT A FOND HORIZONTAL ET A PAROIS CIRCULAIRES PAR LA METHODE DU MODELE RUGUEUX.
- Author
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M., LAKEHAL and B., ACHOUR
- Abstract
Copyright of Larhyss Journal is the property of Biskra University, Research Laboratory in Subterranean & Surface Hydraulics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
14. Phreatic line calculation and stability analysis of slopes under the combined effect of reservoir water level fluctuations and rainfall.
- Author
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Sun, Guanhua, Yang, Yongtao, Zheng, Hong, and Cheng, Shengguo
- Subjects
SLOPE stability ,LANDSLIDES ,RAINFALL ,SAN Xia Reservoir (China) ,RESERVOIRS ,STRAINS & stresses (Mechanics) - Abstract
Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
- Full Text
- View/download PDF
15. Viticulture « adapter le travail à l’homme »
- Author
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Grimbuhler, Sonia and Ruaux, Nathalie
- Subjects
exposition professionnelle ,produit phytosanitaire ,atomiseur ,pente terrain ,[SDV.EE.SANT] Life Sciences [q-bio]/Ecology, environment/Health ,pente ,viticulture ,vibration ,pulvérisateur ,applicateur ,ergonomie ,substance active ,bruit - Abstract
Les viticulteurs et opérateurs viticoles forment une population professionnellement exposée aux produits phytopharmaceutiques. De plus, ils sont exposés à des bruits intenses intermittents qui proviennent de différentes sources (tracteur sans cabine, travail du métal, pulvérisation de produits chimiques…). En l’absence de données spécifiques sur les niveaux de bruit et de vibrations en conditions réelles, il apparaît donc nécessaire d’apporter de nouveaux éléments pour mieux caractériser leurs expositions multiples.
- Published
- 2022
16. Influence de différents agencements de plantation sur le développement racinaire pour assurer l'ancrage et l'alimentation hydrique de peupliers plantés dans du sol recouvrant des pentes de stériles miniers
- Author
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Babi, Khadija and Babi, Khadija
- Abstract
La revégétalisation des sites miniers doit contrôler l’érosion et redonner au site un aspect naturel. Toutefois, dans les régions forestières canadiennes, les conditions favorisant la reconstruction d’un couvert avec des espèces arborescentes sur rejets miniers sont encore mal connues. Bien que les racines assurent plusieurs rôles cruciaux pour les arbres, peu d’études ont été réalisées sur le développement racinaire des arbres sur des stériles miniers. Notamment, les racines jouent un rôle essentiel dans l’alimentation hydrique et minérale ainsi que pour assurer l’ancrage des arbres. Ce projet de doctorat consiste à étudier l’influence de différents agencements de plantation sur la survie et le développement racinaire pour assurer l’ancrage et l’alimentation hydrique des peupliers hybrides plantés sur des pentes de stériles miniers recouvertes de sol superficiel. On a étudié les modifications et les changements importants au niveau du système racinaire, en réponse à différents facteurs. Les principaux facteurs considérés sont : l’espacement entre les arbres, l’hydroensemencement herbacé, la qualité de la couverture de sol, et le matériel de plantation. Cette étude s’est déroulée dans une mine d’or à ciel ouvert située dans la forêt boréale canadienne à Malartic, Québec, Canada. Dans le cadre de cette étude deux plantations de peupliers hybrides ont été installées en 2013 sur des pentes de stériles miniers (33 %) recouvertes de sol. La première plantation de peuplier hybride (P. maximowiczii A. Henry × P. balsamifera L. [M × B] – clone 915 319), visait à étudier l’effet de la compétition inter et intra-spécifique sur l’exposition au stress hydrique, le développement racinaire ainsi que sur l’ancrage des arbres plantés. Quatre traitements répartis aléatoirement dans trois blocs de répétition (total de 12 parcelles expérimentales) ont été évalués : 1 × 1m (10 000 tiges/ha) ; 4 × 4 m (625 tiges/ha) ; 2 ×2 m sans hydroensemencement (2 500 tiges/ha) ; 2×2 m avec hydroens
- Published
- 2021
17. Fuzzification de la distance d'arrêt des avalanches dans les Alpes françaises pour l'aide à la décision en ski de randonnée
- Author
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Pagnier, Fanny, Pourraz, Frédéric, Mauris, Gilles, Coquin, Didier, Verjus, Hervé, and Verjus, Hervé
- Subjects
Aide à la décision ,Pente ,Théorie des sous-ensembles flous ,Distance d’arrêt ,[INFO.INFO-IT] Computer Science [cs]/Information Theory [cs.IT] ,Risque d’avalanches - Abstract
Nous présentons dans ce papier nos travaux réalisés sur l’un des paramètres d’entrée d’un système d’aide à la décision en terrain soumis au risque d’avalanche. En particulier, nous présentons le développement d’un modèle flou permettant d’estimer la distance d’arrêt des avalanches dans les Alpes françaises. Ce modèle, adapté aux massifs alpins français, est développé afin de pallier aux modèles existants, invalides dans ce contexte. Les valeurs obtenues en sortie de ce modèle flou (i.e. les degrés d’appartenance aux ensembles flous décrivant l’aspect sécuritaire ou insécuritaire des distances prises sur le terrain, par les skieurs, par rapport aux pentes avalancheuses) sont ensuite intégrées comme données d’entrée du système global d’aide à la décision combinant un ensemble de paramètres.
- Published
- 2021
18. Synthèse cartographique de la pente des Bahamas
- Author
-
Thierry Mulder, Kelly Fauquembergue, Vincent Hanquiez, Stanislas Wilk, Emmanuelle Ducassou, Emmanuelle Poli, and Sciencesconf.org, CCSD
- Subjects
[SDU] Sciences of the Universe [physics] ,élément architectural ,Bahamas ,Corps sédimentaires ,carbonates ,pente - Published
- 2021
19. Micromechanics of granular materials : Modeling anisotropy by a hyperelastic-plastic model
- Author
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Hu, Lianxin, Géomécanique, Matériaux et Structures (GEOMAS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon, Université de Lyon, Ali Daouadji, Florent Prunier, and STAR, ABES
- Subjects
Modélisation élasto-Plastique ,Mechanical stress ,Pente ,Matériaux ,Déformations plastiques ,Hyperelasticity ,Modèle axisymmétrique ,Elastic-Plastic modelling ,[SPI.MAT] Engineering Sciences [physics]/Materials ,Matériau granulaire ,Contrainte mécanique ,Axisymmetric model ,Elasticity ,[SPI.MAT]Engineering Sciences [physics]/Materials ,Slope ,Hyperélasticité ,Plastic deformation ,Modélisation élastique ,Materials ,Elasticité ,Granular material ,Elastic modelling - Abstract
In order to model the behavior of geometarials under complex loadings, several researches have done numerous experimental works and established relative constitutive models for decades. An important feature of granular materials is that the relationship between stress and strain especially in elastic domain is not linear, unlike the responses of typical metal or rubber. It has been also found that the stress-strain response of granular materials shows the characteristics of cross-anisotropy, as well as the non-linearities. Besides, the stress-induced anisotropy occurs expectedly during the process of disturbance on soils, for example, the loads or displacements. In this work, a new model which is a combination of Houlsby hyperelastic model and elastoplastic Plasol model was proposed. This new model took into account the non-linear response of stress and strain in both elastic and plastic domain, and the anisotropic elasticity was also well considered. Moreover, the overflow problem of plastic strain in plastic part was calibrated by a proper integration algorithm. Later, new model was verified by using numerical method and compared with laboratory experiments in axisymmetric triaxial conditions. The comparison results showed a good simulation effect of new model which just used one single set of parameters for a specific soil in different confining pressure situations. Then the analysis of new model internal variable, i.e., pressure exponent, illustrated that the value of pressure exponent which corresponds to the degree of anisotropy had an obvious effect on the stress-strain response. Moreover, this kind of effect is also affected by the density and drainage condition of samples. Basing on new model, a safety factor which refers to the second-order work criterion was adopted and tested in axisymmetric model and actual slope model. It showed that the negative value or dramatic decreasing of global normalized second-order work occurs accompanying with a local or global failure with a burst of kinetic energy. This feature of second-order work can also be affected by the variable pressure exponent. At last, new model was also compared with an elastoplastic model which considers both anisotropic elastic and anisotropic dilatancy, i.e., modified SANISAND model. Both advantages and disadvantages were illustrated in the comparison results., Afin de modéliser le comportement des géométariaux sous des charges complexes, plusieurs études et travaux expérimentaux ont été réalisées afin d’établir des modèles constitutifs relatifs. Une caractéristique importante des matériaux granulaires est que la relation entre la contrainte et la déformation et ce même dans le domaine élastique n’est pas linéaire, contrairement aux réponses du métal. Il a également été constaté que la réponse contrainte-déformation des matériaux granulaires montre les caractéristiques de l’anisotropie induite, ainsi que les non-linéarités. En outre, l’anisotropie induite par la contrainte se produit pendant le processus de chargement sur les sols, par exemple, les charges ou les déplacements. Dans ce travail, un nouveau modèle qui est une combinaison de modèle hyperélastique Houlsby et modèle élastoplastique Plasol a été proposé. Ce nouveau modèle a pris en compte la réponse non linéaire de la contrainte dans le domaine élastique et plastique, et l’élasticité anisotrope a également été bien considérée. En outre, les problèmes de l’écoulement de la déformation plastique a été calibré par un algorithme d’intégration approprié. Plus tard, le nouveau modèle a été vérifié en utilisant la méthode numérique et comparé aux expériences de laboratoire dans des conditions triaxiales axisymmétriques. Les résultats de comparaison ont montré un bon effet de simulation du nouveau modèle qui a juste utilisé un seul ensemble de paramètres pour un sol spécifique dans différentes situations de contraintes. Ensuite, l’analyse de la nouvelle variable interne du modèle, c’est-à-dire l’exposant de pression, a montré que la valeur de l’exposant de pression qui correspond au degré d’anisotropie a eu un effet évident sur la réponse contrainte-déformation. De plus, ce type d’effet est également affecté par la densité et l’état de drainage des échantillons. En s’appuyant sur un nouveau modèle, un facteur de sécurité qui fait référence au critère de travail de deuxième ordre a été adopté et testé dans un modèle axisymétrique et un modèle de pente réel. Il a montré que la valeur négative ou la diminution spectaculaire du travail global normalisé de second ordre se produit lors d’une défaillance locale ou globale avec apparition d’énergie cinétique. Cette caractéristique du travail du second ordre peut également être affectée par l’exposant à pression variable. Enfin, un nouveau modèle a également été comparé à un modèle élastoplastique qui considère à la fois l’anisotropie élastique et la dilatation anisotrope, c’est-à-dire le modèle SANISAND modifié. Les avantages et les inconvénients ont été illustrés dans les résultats de comparaison.
- Published
- 2020
20. CALCUL DE LA PROFONDEUR NORMALE DANS UNE CONDUITE OVOÏDALE PAR LA METHODE DU MODELE RUGUEUX.
- Author
-
LAKEHAL, M. and ACHOUR, B.
- Abstract
Copyright of Larhyss Journal is the property of Biskra University, Research Laboratory in Subterranean & Surface Hydraulics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2014
21. Contributo para o conhecimento da cosmética islâmica, em Silves, durante a Idade Média
- Author
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Rosa Varela Gomes, Departamento de História (DH), and Instituto de Arqueologia e Paleociências (IAP)
- Subjects
Physics ,Pinça ,Silves ,Tweezers ,Pente ,Kohl pencils ,Cosmética ,Comb ,Cosmetics ,Aplicador de kohl ,Humanities - Abstract
As numerosas escavações que temos dirigido de contextos islâmicos no sul de Portugal, designadamente em Silves, ofereceram, entre muito outro espólio, conjunto artefactual tipologicamente diversificado, que podemos relacionar com a cosmética. Entendemos esta como actividade que usa objectos e produtos destinados não só ao embelezamento, como à conservação e protecção do corpo, nomeadamente no caso dos humanos, da pele, cabelo, olhos, dentes, etc… A cosmética tem existência próxima da medicina e, sobretudo, da farmácia. The numerous excavations that we have conducted from Islamic contexts in the south of Portugal, particularly in Silves, offered, among many other items, a typologically diversified artefact set, which we can relate to cosmetics. We understand this as an activity that uses objects and products intended not only for beautifier, but also for the conservation and protection of the body, namely in the case of humans, skin, hair, eyes, teeth, etc. Cosmetics has a close existence to medicine and, especially, to the pharmacy publishersversion published
- Published
- 2020
22. Slope Optimization (or 'Sloop'): Customized Optimization for Road Longitudinal Profile Eco-Design
- Author
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Vandanjon, Pierre-Olivier, Vinot, Emmanuel, Laboratoire Environnement, Aménagement, Sécurité et Eco-conception (AME-EASE ), Université Gustave Eiffel, and Equipe Eco-gestion des systèmes énergétiques pour les transports (AME-Eco7 )
- Subjects
CONSTRUCTION ROUTIERE ,CONSTRUCTION ,lcsh:T ,TRAFFIC ,lcsh:Technology ,SQP ,ROAD ,[SPI.GCIV]Engineering Sciences [physics]/Civil Engineering ,DYNAMIC MODEL ,GWP ,ROUTE ,TRAFIC ,PENTE ,TRAFIC ROUTIER ,[MATH]Mathematics [math] ,MODELE DYNAMIQUE ,METHODOLOGIE - Abstract
Current transportation systems contributed to one quarter to the Greenhouse Gases (GhG) emissions and the mobility demand increases continuously. The transportation infrastructure design has to be optimized to mitigate these emissions. The methodology &ldquo, Sloop&rdquo, (acronym for Slope Optimization) has recently been set up to optimize the longitudinal road profile with respect to a Global Warming Potential (GWP) criterion calculated for both the construction and operational phases while incorporating accurate vehicle models. This paper proposes a customized optimization strategy that significantly improves the Sloop methodology. From an initial longitudinal profile generated by road designers, our algorithm identifies the optimized profile in terms of GWP. This optimization step is complex due to the large number of degrees of freedom, along with various constraints to obtaining a feasible solution and the computational cost of the operational phase assessment. The most stringent constraint entails connecting the profile with the existing road (i.e., a constraint on the final profile altitude). We have developed a specific algorithm based on the Sequential Quadratic Programming (SQP) method, this algorithm takes into account the quasi-quadratic nature of the constraint on the final altitude. In a real case study, our algorithm outputs a profile whose GWP assessment saves 4% compared to the GWP assessment of the initial profile. The benefit of our specific protocol for treating the final altitude constraint is demonstrated in this example. By means of this new efficient and open-box algorithm, profile evolution at each iteration is analyzed to determine the most sensitive degrees of freedom, and the sensitivity of the optimization with respect to the main construction parameters and traffic assumptions are conducted. The results are consistent and stable.
- Published
- 2020
23. Analyses of groundwater flow and plant evapotranspiration in a vegetated soil slope.
- Author
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Leung, A.K. and Ng, C.W.W.
- Subjects
HYDROGEOLOGY ,SOIL mechanics ,SLOPES (Soil mechanics) ,GROUNDWATER flow ,SUBSURFACE drainage ,SOIL infiltration - Abstract
Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2013
- Full Text
- View/download PDF
24. Measuring slope to improve energy expenditure estimates during field-based activities.
- Author
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Duncan, Glen E., Lester, Jonathan, Migotsky, Sean, Higgins, Lisa, and Borriello, Gaetano
- Subjects
- *
ATMOSPHERIC pressure , *CALORIMETRY , *CONFIDENCE intervals , *ENERGY metabolism , *GEOGRAPHIC information systems , *RESEARCH funding , *WALKING , *ACCELEROMETRY , *OXYGEN consumption , *DATA analysis software , *STATISTICAL models , *DESCRIPTIVE statistics - Abstract
This technical note describes methods to improve activity energy expenditure estimates by using a multi-sensor board (MSB) to measure slope. Ten adults walked over a 4-km (2.5-mile) course wearing an MSB and mobile calorimeter. Energy expenditure was estimated using accelerometry alone (base) and 4 methods to measure slope. The barometer and global positioning system methods improved accuracy by 11% from the base ( p < 0.05) to 86% overall. Measuring slope using the MSB improves energy expenditure estimates during field-based activities. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
25. Topography-adjusted solar radiation indices and their importance in hydrology.
- Author
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Mamassis, Nikos, Efstratiadis, Andreas, and Apostolidou, Ilektra-Georgia
- Subjects
- *
SOLAR radiation , *HYDROLOGY , *LATITUDE , *GEOGRAPHIC information systems - Abstract
Solar radiation, direct and diffuse, is affected by surface characteristics, such as slope, aspect, altitude and shading. The paper examines the effects of topography on radiation, at multiple spatiotemporal scales, using suitable geometric methods for the direct and diffuse components. Two indices are introduced for comparing the direct radiation received by areas at the same and different latitudes. To investigate the profile of direct radiation across the whole of Greece, these are evaluated from an hourly to annual basis, via GIS techniques. Moreover, different approaches are examined for estimating the actual global radiation at operational spatial scales (sub-basin and terrain), according to the available meteorological data. The study indicates that the errors of typical hydrometeorological modelling formulas, which ignore the topographic effects and the seasonal allocation of direct and diffuse radiation, depend on the spatial scale and are non-uniformly distributed in time. In all cases, the estimations are improved by applying the proposed adjustment approaches. In particular, the adjustment of the measured global radiation ensures up to 10% increase of efficiency, while the modified Angström formula achieves slight (i.e. 2–4%) increase of efficiency and notable reduction of bias. Editor Z.W. Kundzewicz Citation Mamassis, N., Efstratiadis, A. and Apostolidou, I.-G., 2012. Topography-adjusted solar radiation indices and their importance in hydrology. Hydrological Sciences Journal, 57 (4), 756–775. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
26. Finite element modelling of pullout testing on a soil nail in a pullout box under different overburden and grouting pressures.
- Author
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Zhou, Wan-Huan, Yin, Jian-Hua, and Hong, Cheng-Yu
- Subjects
SOIL nailing ,FINITE element method ,SPOIL banks ,GROUTING ,PRESSURE ,GRANITE ,STRAINS & stresses (Mechanics) ,DRILLING & boring - Abstract
Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2011
- Full Text
- View/download PDF
27. Influence of deep seated discontinuities on the left slope of Jinping I Hydropower Station and its stability analysis.
- Author
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Qi, Shengwen, Wu, Faquan, Zhou, Yuande, Song, Yuhuan, and Gong, Manfu
- Subjects
- *
WATER power , *METAMORPHIC rocks , *VALLEYS , *ROCK slopes , *EARTH sciences , *SANDSTONE - Abstract
This paper presents a case history detailing the development of cracks within a rock mass up to 350 m from the steeply incised valley slopes of the Yalong river in South West China, where the Jinping I dam is being constructed. The cracks have opened along previous tectonic structural features such that they penetrate further into the rock mass in the metasandstones and slates than in the marble. The presence of these cracks significantly reduces the stability of the near surface rock mass, requiring major excavation at the dam abutment. Analysis has indicated that the most appropriate way of stabilizing the slopes before the dam is constructed is by grout-infilled, specially constructed galleries which extend 60–80 m from the freshly excavated abutment. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
28. Engineering geological problems related to high geo-stresses at the Jinping I Hydropower Station, Southwest China.
- Author
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Gong, Manfu, Qi, Shengwen, and Liu, Jianyou
- Subjects
- *
ENGINEERING geology , *WATER power , *STRAINS & stresses (Mechanics) , *MARBLE , *EXCAVATION , *ROCK slopes - Abstract
The Jinping I Hydropower Station will generate some 3,600 MW. The site of the 305 m high arch dam is in a steep, 1,500–2,500 m deep valley on the Yalong River in Sichuan Province, South West China. The present geo-stresses in the marble bedrock are up to 40 MPa. Relaxation due to river incision has resulted in fractures opening up to 350 m from the rock face. The geo-stresses in the rock mass are significantly affected by the topography. A concentration of stress has developed at the foot of the slope and in the valley floor; it was estimated there would be 132 mm of relaxation/heave of the formation level. The paper discusses some of the engineering geological problems encountered as a result of the high geo-stresses and the mitigation measures undertaken. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
29. Amplification of seismic accelerations at slope crests.
- Author
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Brennan, A. J. and Madabhushi, S. P.G.
- Subjects
SLOPE stability ,CENTRIFUGES ,EARTHQUAKE resistant design ,EARTHQUAKE intensity ,SOIL stabilization - Abstract
Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2009
- Full Text
- View/download PDF
30. Finding the Target in Search Tasks Using Detection, Localization, and Identification Responses.
- Author
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Dukewich, Kristie R. and Klein, Raymond M.
- Subjects
- *
ATTENTION , *TARGET acquisition , *HERMENEUTICS , *ERROR rates , *IDENTIFICATION , *LOCALIZATION theory , *STATISTICAL correlation - Abstract
Visual search is a favourite paradigm for researchers interested in attention because of its ease of implementation and interpretation. Typically, visual search requires the participant to indicate the presence or absence of a prespecified target. Although the slope ratio for present versus absent trials is no longer considered to be indicative of whether search is serial or not, target detection remains a staple amongst studies examining theoretical and empirical aspects of attention. The current study sought to compare within subjects three tasks in a visual search paradigm, detection, localisation, and identification, using identical stimuli. Detection differed in both pattern of error rates and slope from both identification and localisation. Moreover, the slopes from identification and localisation were significantly correlated, whilst neither was significantly correlated with slopes from the detection task. These results suggest that researchers interested in using slopes to estimate search efficiency should use localisation or identification, rather than target detection. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
31. Global boundary controllability of the Saint-Venant system for sloped canals with friction
- Author
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Gugat, M. and Leugering, G.
- Subjects
- *
SAINT-Venant's principle , *ELASTICITY , *FRICTION , *BEARINGS (Machinery) - Abstract
Abstract: We consider a sloped canal with friction that is governed by the Saint-Venant system with source term. We show that starting sufficiently close to a stationary constant subcritical initial state, we can control the system in finite time to a state in a neighbourhood of any other stationary constant subcritical state by boundary control at the ends of the canal in such a way that during the process the system state remains continuously differentiable. Moreover, we show that if the derivative of the initial state is sufficiently small, it can be steered to every stationary constant subcritical state in finite time. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
32. Flow resistance in large-scale roughness condition.
- Author
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Das, Rajib, Carnacina, Iacopo, and Pagliara, Stefano
- Subjects
- *
FLOWS (Differentiable dynamical systems) , *SURFACE roughness , *ROCKS , *LOGARITHMS , *BOULDERS , *ROCK slopes , *SLOPES (Physical geography) - Abstract
This paper presents an experimental investigation of the flow resistance in long chutes with a slope of up to 9% and large-scale roughness. Rock chutes generally have steep slopes and the presence of large rocks induces great resistance to the flow. The chute bed was characterized by different sizes of crushed stones with protruding boulders. The proposed relationship correlates the flow resistance in terms of the Darcy-Weisbach friction factor with and without protruding boulders. The proposed logarithmic law is a function of the relative submergence, the slope, and the boulder concentration. A comparison of the data calculated using the proposed logarithmic law with those from earlier experiments shows a reasonable agreement in the tested experimental range. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
33. Parallel patterns of clinal variation in Solidago altissima in its native range in central USA and its invasive range in Japan.
- Author
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Etterson, Julie R., Delf, Daniel E., Craig, Timothy P., Ando, Yoshino, and Ohgushi, Takayuki
- Subjects
- *
INTRODUCED species , *BIOLOGICAL adaptation , *EVOLUTIONARY theories , *PHENOTYPES , *ENVIRONMENTAL impact analysis - Abstract
The ability of exotic species to proliferate and expand their range may hinge critically upon their potential for adaptive evolution. The finding of parallel patterns of genetically based clinal variation in native and non-native ranges across similar environmental gradients supports the hypothesis that adaptive evolution has played a role in establishment and spread. In this common garden study, we compared patterns of phenotypic variation among 12 populations of Solidago altissima L. that were sampled across similar latitudes in the native range in central USA (25°N–43°N) and across its invasive range in Japan (26°N–43°N). Significant clinal variation in phenotype corresponding to latitude was found among US and Japanese populations for height, leaf number, leaf length, leaf width, stem diameter, and stomatal guard-cell size. Only the slope of leaf width differed significantly between the native and invasive range, and the slope was significantly steeper in Japan. These results indicate that patterns of selection across latitude are similar in these two countries. We suggest that populations of S. altissima have rapidly differentiated in response to the cline in selection in Japan, possibly by the sorting of lineages from multiple introductions, and this has contributed to their success as an exotic invader. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
34. Steep slopes promote downhill dispersal of Quercus crispula seeds and weaken the fine-scale genetic structure of seedling populations.
- Author
-
Ohsawa, Takafumi, Tsuda, Yoshiaki, Saito, Yoko, Sawada, Haruo, and Lde, Yuji
- Abstract
Copyright of Annals of Forest Science (BioMed Central) is the property of BioMed Central and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2007
- Full Text
- View/download PDF
35. Prediction of evaporation from soil slopes.
- Author
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Weeks, B. and Wilson, G. W.
- Subjects
EVAPORATION (Chemistry) ,SOIL mechanics ,WASTE disposal sites ,SOLAR radiation ,SOILS - Abstract
Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2006
- Full Text
- View/download PDF
36. A practical design approach for reducing the occurrence of shallow slides in cohesionless till highway embankments.
- Author
-
Konrad, J.-M. and Grondin, G.
- Subjects
GLACIAL drift ,SEDIMENTS ,SOIL liquefaction ,SHEAR strength of soils ,SOIL mechanics ,SLOPES (Soil mechanics) - Abstract
Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2005
- Full Text
- View/download PDF
37. A new procedure for computing the factor of safety using the Morgenstern-Price method.
- Author
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Zhu, D Y, Lee, C F, Qian, Q H, Zou, Z S, and Sun, F
- Subjects
EQUILIBRIUM ,NEWTON-Raphson method ,ITERATIVE methods (Mathematics) ,COMPUTER software ,SAFETY factor in engineering - Abstract
By employing the same assumption regarding interslice forces as that used in the Morgenstern-Price method, two concise recurrence relations between interslice forces and interslice moments are derived which satisfy both force and moment equilibrium conditions. The Newton-Raphson method is used for determining the factor of safety and the associated scaling parameter of the interslice force function. Algebraic derivatives required in the solution process are evolved in a recursive manner which can be easily implemented in a computer program. The choices of initial values of safety factor and scaling parameter are suggested. The procedure proposed in this paper proves to be efficient and solutions converge rapidly.Key words: slope, stability, factor of safety, limit equilibrium method.En utilisant les mêmes hypothèses concernant les forces intertranches que celles utilisées dans la méthode de Morgenstern-Price, on dérive deux relations concises de répétitions entre les forces intertranches et entre les moments intertranches qui satisfont les conditions d'équilibre tant des forces que des moments. La méthode Newton-Raphson est utilisée pour déterminer le coefficient de sécurité et le paramètre d'échelle associé de la fonction de force entre les tranches. Les dérivées algébriques requises dans le processus de solution sont développées de façon récursive, ce qui peut être facilement exécuté par un programme d'ordinateur. On suggère les choix des valeurs initiales du coefficient de sécurité et du paramètre d'échelle. La procédure proposée dans cet article se montre efficiente et les solutions convergent rapidement.Mots clés : pente, stabilité, coefficient de stabilité, méthode d'équilibre limite.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
38. A method for locating critical slip surfaces in slope stability analysis.
- Author
-
Zhu, Da-Yong
- Subjects
SLOPE stability ,SOIL stabilization ,STABILITY (Mechanics) ,ENGINEERING ,NUMERICAL analysis - Abstract
This paper presents a new method for locating critical slip surfaces of general shapes in slope stability analysis. On the basis of the principle of optimality, along with the method of slices, a critical slip field (CSF) in a slope is postulated which consists of a family of slip surfaces having maximum values of unbalanced thrust forces at exit points on the slope face. A numerical procedure is developed for constructing the CSF. The critical slip surface having minimum factor of safety is included in the CSF. All the critical slip surfaces corresponding to all of the exit points are thus determined consecutively, resulting in a global critical slip field (GCSF) which exhibits both global and local slope stability. Comparisons with other methods are made which indicate the high efficiency and accuracy of the proposed approach. Applications of the proposed method to two case examples are given, the results of which demonstrate its applicability to practical engineering.Key words: slope, stability, analysis, factor of safety, critical slip field.Cet article présente un nouvelle méthode pour localiser les surfaces critiques de glissement de formes générales dans l'analyse de stabilité. Sur la base du principe d'optimisation, on postule en combinaison avec la méthode des tranches, un champ critique de glissement (CSF) qui consiste en une famille de surfaces de glissement ayant des valeurs maximales de forces de poussées entre les tranches qui sont non balancées aux points de sortie sur la surface de la pente. Un procédure numérique est développée pour construire le CSF. Toutes les surfaces critiques de glissement correspondant à tous et chacun des points de sortie sont alors déterminées consécutivement ce qui résulte en un champ global critique de glissement (GCSF) qui indique la stabilité tant globale que locale de la pente. On fait des comparaisons avec d'autres méthodes qui démontrent la haute efficience et précision de l'approche proposée. On donne les applications de la méthode proposée à deux exemples de cas, dont les résultats montrent son applicabilité à la pratique du génie.Mots clés : pente, stabilité, analyse, coefficient de sécurité, champ critique de glissement.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
39. Generation of soil drainage equations from an artificial neural network-analysis approach.
- Author
-
Zhengyong Zhao, MacLean, David A., Bourque, Charles P.-A., Swift, D. Edwin, and Fan-Rui Meng
- Subjects
ARTIFICIAL neural networks ,SOIL mapping ,DIGITAL elevation models ,SEDIMENTATION & deposition ,SOIL management - Abstract
Copyright of Canadian Journal of Soil Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2013
- Full Text
- View/download PDF
40. Transferts sédimentaires sur une marge carbonatée moderne de la plate-forme à la plaine abyssale : marge nord de Little Bahama Bank, Bahamas
- Author
-
Fauquembergue, Kelly and Fauquembergue, Kelly
- Abstract
Over the past decade, the Little Bahamas Bank (LBB) in the Caribbean has been at the heart of oceanographic cruises Carambar (2010), Caramba 1.5 (2014) and Carambar 2 (2016-2017). These scientific expeditions were carried out with the aim of improving our knowledge of the processes that controlled sediment export during the Quaternary in this tropical setting. Thus, bathymetric data covering some 24,270 km² of seabed, high-resolution seismic lines running over 6,398 km and 42 sediment cores ranging from 177 to 4,873 m water depth were collected in the upper slope through to the abyssal plane of the LBB system. This study focusses on those sediment cores retrieved in the upper (Carambar 1.5) and lower slope of the LBB and those from the Great Canyon (Carambar 2) which is connected to the abyssal plane. These results are complementary to previous studies led on the middle and lower northern slope of the LBB (Tournadour, 2015; Chabaud, 2016). A highstand accretion wedge, currently dated to the Holocene, expands at water depths of 177-360 m. Sediment deposition in the prism is mainly the result of hurricanes and density cascading. Its initiation is dated at 13. 6 ± 3.5 ka cal BP, following Meltwater Pulse 1A. Melwater Pulses led to the formation of shallow terraces that enhanced carbonate production and ultimately supplied the wedge with sediment through the export of said carbonate. The height of the development of the wedge occurred at 6.56 ± 0.9 ka cal BP when the sea level reached the shelf-break. Sedimentation in the lower slope is indicative of more pelagic processes, since currents play a greater part in the deposition of sediment than the shelf. Variability in the facies of theses deposits are thus the result of climatic variations (e.g strengthening of currents, influxes of Arctic water). Sediments in this area share similarities with those in Blake Outer Ridge, 400 km north of the LLB. At water depth of 1,300-4,800 m, the slope is scored by a giant canyon, nam, Les missions océanographiques Carambar (2010), Carambar 1.5 (2014) et Carambar 2 (2016-2017) menées au large de la pente nord du Petit Banc des Bahamas (PBB) ont permis d’étudier les processus d’export sédimentaire quaternaires sur ce système carbonaté. Les 24 270 km² de données bathymétriques couplées aux 6398 km de lignes sismiques très haute-résolution et aux 42 carottes sédimentaires reparties entre – 177 m et – 4873 m de profondeur ont permis de caractériser ce système depuis la pente supérieure jusqu’à la plaine abyssale. Le travail présenté ici s’intéresse aux résultats obtenus sur les carottes sédimentaires prélevées sur le haut de pente supérieur du PBB (Carambar 1.5) et celles obtenues sur le bas de pente et dans la zone du canyon du Great connecté à la plaine abyssale (Carambar 2). Ils viennent compléter les résultats obtenus précédemment par Tournadour (2015) et Chabaud (2016) sur les pentes inférieures et moyennes. Un prisme de haut niveau marin se dépose haut de pente supérieure. Actuellement, ce prisme daté de l’holocène s’étend de - 177 m à – 360 m. Les dépôts sédimentaires sont principalement engendrés par le density cascading et le passage d’ouragans. Son alimentation La formation du prisme a débuté il y a 13,6 ± 3,5 ka cal BP, après le Meltwater Pulse 1A. Les Meltwater Pulses ont engendré la formation de terrasses qui correspondent alors à des environnements peu profonds et qui induisent une production carbonatée qui peut être exportée vers le prisme. La principale phase de développement du prisme est datée à 6,5 ± 0,9 ka cal BP, quand le niveau marin a finalement atteint le rebord de plate-forme. La sédimentation du bas de pente suggère une alimentation principalement pélagique et liée aux passages des courants plutôt qu’aux apports de plate-forme. Les variations dans les faciès dans ces dépôts sont donc issues de variations climatiques (intensification des courants, apports arctiques). La sédimentation de cette zone semble similaire à celle retr
- Published
- 2018
41. Extracting topographic characteristics of landforms typical of Canadian agricultural landscapes for agri-environmental modeling. I. Methodology.
- Author
-
Sheng Li, Lobb, David A., McConkey, Brian G., MacMillan, R. A., Moulin, Alan, and Fraser, Walter R.
- Subjects
ARABLE land ,LANDFORMS ,LANDSCAPES ,SCIENTIFIC method ,SOIL testing ,TOPOGRAPHICAL surveying ,MATHEMATICAL models - Abstract
The article reports on the methodology of extracting topographic features of landscape to classify it in various landforms for agri-environmental models. The analyses of topographic characteristics are done by full dissolution of digital elevation models (DEMs). Analyses used in finding the two dimensional hillslope and slope inclination in each sector which helps in knowing the topographic instability in three dimension area of Canada.
- Published
- 2011
- Full Text
- View/download PDF
42. Effets de l’élevage sur les risques d’érosion en Colombie
- Author
-
Hermelin, M. and Aristazabal, A. F.
- Subjects
région tropicale ,sol ,Colombie ,pente ,Columbia ,érosion ,pied de vache ,erosion ,élevage ,cattle tracks ,POL044000 ,pluies cycloniques ,breeding ,slope ,biomasse ,RND - Abstract
L´introduction des bovins dans les Andes colombiennes a été une des causes de la destruction des forêts, mais aussi de l´invasion des Paramos qui se développent a partir de 3500 m dans les régions humides. L´apparition de « terrassettes » formées par piétinement entraîne un déplacement du sol et son tassement, donc une augmentation du ruissellement et éventuellement des glissements de terrain. L´étude préliminaire présentée ici a eu lieu dans les environs de Medellin (6° 30 N latitude) entre 1800 et 2500 m d´altitude, sous un climat humide et sur des sols acides dérivés de cendres volcaniques dacitiques et de roches cristallines. Après le choix des sites, les mesures sur le terrain ont été réalisées à l´aide d´une tige métallique munie d´un niveau et d´un distanciomѐtre. Les échantillons choisis ont été analysés quant à leur matiѐre organique, leur humidité et leur densité. Les pentes à partir desquelles apparaissent les terrassettes vont de 22.5° à 46°. Des différences significatives ont été observées sur les densités, de 0.61 a 0.78 g cm-3, ces dernières d´échantillons ayant été prélevés sur les zones tassées par le cheminement du bétail, dont les pattes produisent une pression calculée entre 4.0 et 6.5 kg cm-2. Le travail préliminaire devrait être complété par des études plus systématiques tenant compte du temps d´occupations des sols, des méthodes d´exploitation et de la nature des roches sous jacentes. De plus les régions séches doivent être étudiées en détail, car les processus peuvent y devenir plus prononcés. The implantation of cows in the Colombian Andes have caused the destruction of forest but also the invasion of Paramos, which occur at altitudes of more than 3500 m in humid regions. The occurrence of “terrassettes” formed by cattle trampling causes a down slope displacement of soil and its compaction, thus an increase of runoff and a possible evolution toward land sliding. The preliminary results presented here were obtained around Medellin (6° 30 N latitude) at altitudes between 1800 and 2500 m a s l, with a humid climate and on soils derived from dacitic volcanic ashes and weathered crystalline rocks. Once the sites were selected, ground measurements were carried out with a metallic rod equipped with a level and with a distance meter. Samples were analyzed in laboratory for organic matter, water content an density. “Terrassettes” were observed in slopes from 22.5 to 46°. Significant differences were observed in densities, from 0.61 to 0.78, the latter in areas compacted by cattle sabot, which apply a pressure calculated between 4.0 and 6.5 kg cm-2.. This preliminary paper should be completed by more systematic studies including grazing procedures and the composition of underlying rocks. Furthermore dry regions should be studied in detail as processes may there become more important.
- Published
- 2018
43. Atmosphere–vegetation–soil interactions in a climate change context; impact of changing conditions on engineered transport infrastructure slopes in Europe
- Author
-
V. Van Beek, Stanislav Lenart, H.W. ter Maat, J.J. Diez, Tom Dijkstra, Amin Askarinejad, Anh Minh Tang, F. Gentile, Cristina Jommi, Ross Stirling, Beata Gajewska, Fotini Kehagia, David G. Toll, Eugeniusz Koda, T. Firgi, Sérgio D. N. Lourenço, M. Oliveira, Sarah M. Springman, Mihael Brenčič, Paul Hughes, Piotr Osiński, Giovanna Grossi, Yu-Jun Cui, Laboratoire Navier (navier umr 8205), École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Dipartimento di Ingegneria Civile, Università degli Studi di Brescia [Brescia], POLITECNICO DI MILANO ITA, Partenaires IRSTEA, and Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
- Subjects
ENGINEERED SLOPE ,0211 other engineering and technologies ,Climate change ,CLIMATE CHANGE 39 40 ,Context (language use) ,02 engineering and technology ,Atmosphere ,11. Sustainability ,Geotechnical Analysis ,Earth and Planetary Sciences (miscellaneous) ,Life Science ,Cost action ,Climate actions ,021101 geological & geomatics engineering ,SOL ,business.industry ,Environmental resource management ,Infrastructures ,Geology ,04 agricultural and veterinary sciences ,Vegetation ,ATMOSPHERE ,Geotechnical Engineering and Engineering Geology ,SOIL ,INTERACTION SOL STRUCTURE ,Climate Resilience ,[SPI.GCIV]Engineering Sciences [physics]/Civil Engineering ,Klimaatbestendigheid ,13. Climate action ,Desiccation cracking ,Infrastructures, Climate actions, Geotechnical Analysis ,PENTE ,040103 agronomy & agriculture ,Erosion ,0401 agriculture, forestry, and fisheries ,Environmental science ,VEGETATION ,business ,INTERACTION ,Transport infrastructure - Abstract
In assessing the impact of climate change on infrastructure, it is essential to consider the interactions between the atmosphere, vegetation and the near-surface soil. This paper presents an overview of these processes, focusing on recent advances from the literature and those made by members of COST Action TU1202 – Impacts of climate change on engineered slopes for infrastructure. Climate- and vegetation-driven processes (suction generation, erosion, desiccation cracking, freeze–thaw effects) are expected to change in incidence and severity, which will affect the stability of new and existing infrastructure slopes. This paper identifies the climate- and vegetation-driven processes that are of greatest concern, the suite of known unknowns that require further research, and lists key aspect that should be considered for the design of engineered transport infrastructure slopes in the context of climate change. ISSN:1470-9236 ISSN:0481-2085
- Published
- 2018
44. Seismically induced effects and slope stability in urbanized areas via numerical modeling
- Author
-
Domej, Gisela, Sols, Roches et Ouvrages Géotechniques (IFSTTAR/GERS/SRO), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Communauté Université Paris-Est, Séismes et Vibrations (IFSTTAR/GERS/SV), Université Paris-Est, IFSTTAR - Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux, Jean-François Semblat, and Luca Lenti
- Subjects
landslides ,STABILITE DES TALUS ,[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] ,[SPI.GCIV.GEOTECH]Engineering Sciences [physics]/Civil Engineering/Géotechnique ,séismes ,MODELISATION NUMERIQUE ,SISMIQUE ,numerical modeling ,modélisation numérique ,SEISME ,glissements de terrain ,PENTE ,GLISSEMENT (TERRAIN) ,earthquakes ,STABILITE DES PENTES - Abstract
Seismically induced slope deformation is a worldwide common phenomenon that poses an increasing and considerable threat to fast expanding urbanization, and a great number of catastrophic events throughout the past attest thereof. For this reason, displacement predictions allowing for proper slope surveillance became a major concern.Early attempts to relate slope failures to seismic parameters are of empirical nature and date back to the 1980s. Although having proven stable, these relations are frequently disturbed by site effects causing outliers in terms of smaller or greater displacements than expected.The first part of this thesis presents a newly build chronological database of 277 globally distributed seismically and non-seismically induced landslides. A comprehensive statistical analysis was conducted on the data of this database with the main result that – statistically seen – the average geometrical shapes of landslides differ only proportionally. The second part of the thesis is dedicated to a comparative slope stability analysis of the Diezma Landslide (Spain) by means of three methods: the limit-equilibrium based NEWMARK-Method (1965) in 2D under elasto-perfectly-plastic conditions; finite-difference analysis in the time domain with the code FLAC in 2D and 3D under visco-elasto-perfectly-plastic conditions; and modal recombination analysis in the frequency domain with the finite-element code CESAR-LCPC in 2D and 3D under visco-elastic conditions.Located in a seismically active region, the Diezma Landslide is likely to be affected by earthquakes and was therefore considered as a suitable model case. A broad analysis of expected displacements was conducted using eleven strong-motion seismic scenarios. Moreover, the thesis searches for potential relations between macro-seismic parameters of the applied earthquake scenarios and the predicted deformations obtained from the three methods. It appeared that – due to the functionality of the methods – results differ quantitatively as well as qualitatively, and so does their suitability. Major findings are: (a) Results from the three methods are of different orders of magnitude and, thus, can easily lead to over- or under-estimations of displacements; (b) Both numerical methods reveal a strong influence of the model-geometry on the predicted displacements, whereas a scenario-dependent slope behavior manifested itself only within the finite difference analysis; (c) The switch from 2D to 3D does not necessarily result in a similar performance in each dimension and results must be critically judged before further use; (d) The NEWMARK-Method (1965) has proven itself once more to be appropriate for first slope assessments but not for sophisticated evaluations of ground response to seismic shaking.; Les phénomènes d’instabilité générés par les séismes dans les pentes représentent un risque naturel majeur à l’échelle mondiale. Ce risque a, de plus, tendance à croître du fait d’une urbanisation croissante dans des zones à fort aléa, comme en témoignent de nombreux évènements catastrophique à travers le passé. Pour garantir la sécurité des personnes et des biens face à ce type d’aléa, il faut améliorer les prédictions des déplacements générés par les séismes dans les pentes.Les premiers travaux scientifiques visant à corréler les caractéristiques des instabilités dans les pentes aux paramètres sismiques sont de nature empirique et remontent aux années 1980. Ces méthodes ne permettent pas d’expliquer tous les mouvements de terrain observés à travers le monde, notamment lorsque les effets de site modifient sensiblement la distribution des mouvements dans les pentes et génèrent des déplacements plus grands ou plus petits que ceux prédits par les lois empiriques qui négligent les effets de site.La première partie de cette thèse présente une nouvelle base de données mondiale de 277 glissements de terrain d’origine sismique ou non. L’analyse statistique conduite sur les données de cette base a montré que la forme géométrique moyenne des glissements de terrain reste stable lorsque le volume des instabilités augmente.La deuxième partie de la thèse est dédiée à l’analyse de la stabilité du glissement de terrain de Diezma (Espagne) au moyen de trois méthodes : la Méthode de NEWMARK (1965) basée sur le principe de l’équilibre limite en 2D qui suppose des conditions elasto-parfaitement-plastiques ; l’analyse par différences finies dans le domaine temporel avec le code FLAC en 2D et en 3D qui suppose des conditions visco-elasto-parfaitement-plastiques ; et l’analyse par recombinaison modale dans le domaine fréquentiel avec le code CESAR-LCPC en 2D et en 3D qui suppose des conditions visco-élastiques.Situé dans une région sismiquement active, le glissement de terrain de Diezma est susceptible d’être affecté par des séismes. Une analyse des déplacements induits dans ce versant par onze signaux sismiques différents a été menée dans l’objectif d’établir des corrélations entre les paramètres macro-sismiques des scenarios sismiques appliqués et les déformations calculées par les trois méthodes.Les résultats montrent des différences marquées à la fois qualitatives et quantitatives. Les conclusions principales sont : (a) Les déplacements obtenus par les trois méthodes ont des ordres de grandeur différents et peuvent donc conduire à une surestimation ou à une sous-estimation des déplacements ; (b) Les deux méthodes numériques montrent que les déplacements sont fortement conditionnés par la géométrie des modèles ; seule la méthode par différences finies fait apparaître une réponse en termes de déplacements qui dépend du scénario sismique considéré; (c) Les résultats des simulations2D et 3D ne sont pas comparables ; des analyses complémentaires doivent encore être menées pour guider l’utilisateur dans le choix de la méthode la plus appropriée; (d) La Méthode de NEWMARK (1965), dont l’utilisation reste très répandue de nos jours, est tout à fait appropriée à l’étude de cas simples mais elle peut se révéler inexacte lorsque la structure géologique / topographique du versant conduit à un fort effet de site car ce dernier n’est pas pris en compte par cette méthode.
- Published
- 2018
45. Spatial filtering of electrical resistivity and slope intensity: Enhancement of spatial estimates of a soil property
- Author
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Sébastien Salvador-Blanes, Hocine Bourennane, Florent Hinschberger, Caroline Chartin, Unité de recherche Science du Sol (USS), Institut National de la Recherche Agronomique (INRA), GéoHydrosystèmes COntinentaux (GéHCO EA6293), Université de Tours, Centre Georges Lemaître for Earth and Climate Research [Louvain] (TECLIM), Earth and Life Institute [Louvain-La-Neuve] (ELI), Université Catholique de Louvain (UCL)-Université Catholique de Louvain (UCL), Financial support provided by the ANR (Agence Nationale de la Recherche) (ANR-08-VMCS-00) VMCS project LANDSOIL is gratefully acknowledged., Université Catholique de Louvain = Catholic University of Louvain (UCL)-Université Catholique de Louvain = Catholic University of Louvain (UCL), and Université de Tours (UT)
- Subjects
high-resolution methods ,Scale (ratio) ,Mean squared error ,géostatistique ,krigeage avec dérivés externes ,High resolution electrical resistivity ,Principal component analysis ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Soil science ,010502 geochemistry & geophysics ,épaisseur du sol ,01 natural sciences ,estimation spatiale ,Electrical resistivity and conductivity ,Kriging ,Kriging spatial components ,krigeage ,Statistics ,analyse en composantes principales ,kriging ,geostatistics ,résistivité électrique ,Digital elevation model ,0105 earth and related environmental sciences ,haute résolution ,Spatial filter ,pente ,04 agricultural and veterinary sciences ,Slope intensity ,Geophysics ,Multiple external drifts ,040103 agronomy & agriculture ,slope ,0401 agriculture, forestry, and fisheries ,gradient de la pente ,Intensity (heat transfer) ,Geology ,Soil thickness ,electrical resistivity - Abstract
To best utilize the electrical resistivity data and slope intensity derived from a Digital Elevation Model, the kriging spatial components technique was applied to separate the nuggets and small- and large-scale structures for both resistivity and slope intensity data. The spatial structures in the resistivity and slope intensity data, which are poorly correlated with soil thickness (ST), are then filtered out prior to integrating the resistivity data and slope intensity into soil thickness estimation over a 12 ha area located in the south-western Parisian Basin (France). ST was measured at 650 locations over the study area by manual augering. Twenty percent of the observations (131 points) were randomly selected to constitute the validation dataset. The remaining 80% of the dataset (519 points) was used as the prediction dataset. The resistivity data represent a set of 7394 measurement points for each of the three investigated depths over the study area. The methodology involves successively (1) a principal component analysis (PCA) on the electrical measurements and (2) a geostatistical filtering of the small-scale component and noise in the first component (PC1) of the PCA. The results show that the correlation between ST and PC1 is greatly improved when the small-scale component and noise are filtered out, and similarly, the correlation between ST and slope intensity is greatly improved once the geostatistical filtering is carried out on the slope data. Thus, the large scales of both slope intensity and the electrical resistivity's PC1 were used as external drifts to predict ST over the entire study area. This prediction was compared with ordinary kriging and kriging either with a large scale of slope intensity or with a large scale of the electrical resistivity's PC1 taken as an external drift. The first prediction of ST by ordinary kriging, which was considered as our reference, was also compared to those achieved by kriging using the raw secondary variables: PC1 and slope intensity as external drifts; slope intensity as an external drift; and PC1 as an external drift. The results indicate a reasonably low bias of prediction for all of the methods, in particular in the case of kriging using the large scales of both slope intensity and PC1 as external drifts. The root mean square error shows that kriging accounting for the large scales of two secondary exhaustive variables is the most accurate prediction method. The relative improvement of the accuracy is at least equal to 29% between the approach accounting for both large scale components of secondary attributes in the spatial estimates of ST and the other approaches of estimates considered in this study.
- Published
- 2017
46. Seasonal hydrological impacts of land use on hillslope stability
- Author
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Kim, John, de Rouw, Anneke, Fourcaud, Thierry, Maeght, Jean-Luc, Mao, Zhun, Metayer, James, Meylan, Louise, Pierret, Alain, Rapidel, Bruno, Villatoro, Mario, Wang, Yan, Stokes, Alexia, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut de Recherche pour le Développement (IRD), Institut d'écologie et des sciences de l'environnement de Paris (IEES), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), Fonctionnement et conduite des systèmes de culture tropicaux et méditerranéens (UMR SYSTEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre International de Hautes Etudes Agronomiques Méditerranéennes - Institut Agronomique Méditerranéen de Montpellier (CIHEAM-IAMM), Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud]), Département Systèmes Biologiques (Cirad-BIOS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Institut d'écologie et des sciences de l'environnement de Paris (iEES), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Centre International de Hautes Etudes Agronomiques Méditerranéennes - Institut Agronomique Méditerranéen de Montpellier (CIHEAM-IAMM), Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Département Performances des systèmes de production et de transformation tropicaux (Cirad-PERSYST), and Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Vegetal Biology ,stabilité du sol ,soil stabilization ,laos ,pente ,variabilité hydrologique ,costa rica ,utilisation des terres ,stabilisation du sol ,land equivalent ratio ,slope ,land-use management ,[SDV.BV]Life Sciences [q-bio]/Vegetal Biology ,pente du sol ,Hydrology ,[SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology ,france ,Biologie végétale ,Hydrologie ,gestion du territoire - Abstract
Shallow landslides can pose a major threat to human lives and infrastructure over significant portions of the global land surface and occur primarily from weakened soil shear resistance due to water infiltration. Although there is growing interest in using vegetation to stabilize hillslopes against landslides, we noted the scarcity of studies examining temporal variations in slope stability, particularly with regard to different land uses. In three tropical and temperate landslide-prone regions (Laos, Costa Rica and France), we combined soil moisture monitoring to 1.2-1.8 m depths in the field, soil shear resistance measurements and numerical modeling to compare slope stability under competing land uses for 2-3 years. Slope stability tracked temporal changes in soil moisture, with smaller contributions from root mechanical reinforcement. Land uses with denser vegetation had greater stabilizing impacts than those with sparser vegetation, which lasted for six to twelve months per year and coincided temporally with growing or rainy/dry seasons. Greater stability under denser land use persisted into wet seasons in one of the sites and were minimized or reversed in the other two sites. Site-specific factors such as climate, soil and species may explain these differences in the vegetational control on slope stability. A review of the data in the literature found that woody vegetation increased slope stability and decreased temporal variation in stability compared to herbaceous vegetation. However, while variations in slope stability decreased in increasingly humid climates, indicating that the largest fluctuations in stability, and hence potential to improve slope integrity with land-use changes, will be found in arid to sub-humid regions. Our results show that dense vegetation provides greater stability and protection against landslides from rainfall. Land managers need to take into account this biological control on hydrology when managing vegetated slopes. Incorporating the vegetation-driven deep soil moisture dynamics will also improve predictive utility of models of specific events.
- Published
- 2016
47. Évaluation et modélisation de l’érosion du sol sous différentes pratiques de conservation sur les plantations de café ombragées sur les terres de pente (Ultisols) au Costa Rica
- Author
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Villatoro, Mario, Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème (UMR LISAH), Institut de Recherche pour le Développement (IRD)-Institut de Recherche pour le Développement (IRD [ Madagascar])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), Montpellier SupAgro, Yves Le Bissonnais, Bruno Rapidel, Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)
- Subjects
Slope ,[SDV.SA]Life Sciences [q-bio]/Agricultural sciences ,Erosion ,Pente ,Modélisation ,Modeling ,Café ,Coffee ,Ultisols - Abstract
Id prodinra: 384489; The main objective of this work was to better understand soil erosion processes and dynamics on steep lands cultivated with a permanent crop (shade coffee).Eight large experimental plots were installed in a 65% average slope coffee plantation with Erythrina sp. as shade tree. The superficial runoff was measured every 5 min. and collected for sediment concentration measurement and soil loss assessment.Rainfall depth was 2206, 1778 and 2220 mm in 2011, 2012 and 2013 respectively with a marked succession of dry season and rainy season. Total runoff was 103, 54 and 33 mm along those three years. Annual average sediment concentration at plot scale was about 1.3 g l-1 with reduced temporal variations between years or rainfall events. The plots' average annual soil loss (under normal management) decreased from 1.69 to 0.91 and 0.58 t ha-1 from 2011 to 2013. An analysis of the temporal dynamics was performed in three time scales: annual-monthly, event and intra-event. Around 60% of rainfall and 90% of runoff and soil loss occurred each year during the August-October periods and more than half of it in October. Total event rainfall and soil water content explained most of surface runoff and soil loss dynamics, while inherited soil water storage from previous year played an important role on the relationship between rainfall and runoff dynamics the following year. A simple infiltration model (Diskin and Nazimov) was used to estimate runoff during a rainfall event.In 2012 four treatments were applied with two replicates each: no mini-terraces renewal, weed control with herbicide, reduced pruning pressure on shade trees and reference management. Three periods were considered: P1 before treatment application, P2 the next two months afterwards and P3 the year after (2013). The significant differences between treatments/reference ratios for the three periods suggested higher runoff and sediment concentration when mini-terraces were renewed and the effect decreased but was still present in P3. Chemical weed control did not show a clear trend. The reduced pruning treatment reduced erosion only for superficial soil moisture >30%.Superficial runoff, average sediment concentration and soil loss were monitored at the outlet of a small watershed (31 ha, 60% average slope) during 2012 and 2013. Rainfall events greater than 5 mm (169 events) produced runoff at both scales and most of runoff amount was produced for strong rainfalls (> 40 mm). The runoff coefficients were very low (0.9%) at both scales in 2013. But it was 2.44% for plots and 0.9% for watershed in 2013. The base flow was also very low on this watershed (13-16% of total rainfall) with a large part of the rainfall (about 20%) being lost by percolation. The average sediment concentration at the plots was about 1.65 g l-1 and the maximum value was 5.64 g l-1. The average sediment concentration at watershed scale was 0.51 g l-1. Estimated annual soil loss were 0.73 and 0.36 t ha-1 yr-1 at plots scale (all managements included) for 2012 and 2013 respectively and 0.46 and 1.24 t ha-1 yr-1 at watershed scale for thesame years.The shade coffee system studied showed a tolerable soil loss compared to the potential erosion due to the efficient vegetal surface protection.; L'objectif principal de ce travail était de mieux comprendre les processus et la dynamique d'érosion des sols sur pentes raides sous culture permanente (café sous arbres d'ombrage).Huit parcelles expérimentales ont été installées dans une plantation de café avec une pente moyenne de 65 % avec Erythrina sp. comme arbre d'ombrage. Le ruissellement superficiel a été mesuré chaque 5 min et collecté pour la mesure de la concentration en sédiments et l'évaluation de l'érosion.La pluviométrie annuelle a été de 2206, 1778 et 2220 mm en 2011, 2012 et 2013 respectivement avec une alternance marquée de saison sèche et saison des pluies. La lame ruisselée totale a été en moyenne de 103, 54 et 33 mm respectivement pour les trois années. La concentration moyenne en sédiments a été d'environ 1.3 g l-1 avec des variations temporelles réduites entre événements pluvieux et entre années. La perte de sol annuelle moyenne a diminué de 1.69 à 0.91 puis 0.58 t ha-1 an-1 de 2011 à 2013. La dynamique temporelle a été analysée à trois échelles de temps : annuel-mensuel, événement et intra-événement. Environ 60% de la pluie et 90% du ruissellement et de l'érosion s'est produit pendant les périodes d'octobre à aout, dont plus de la moitié en octobre. La hauteur de pluie de chaque événement et la teneur en d'eau du sol ont expliqué l'essentiel de la variabilité du ruissellement et de la perte en terre. Le stockage d'eau de sol hérité de l'année précédente a joué un rôle important sur le ruissellement. Un modèle d'infiltration simple (Diskin et Nazimov) a été utilisé pour évaluer la hauteur de ruissellement pendant une pluie.En 2012 quatre traitements ont été appliqués avec deux répétitions chacun : 1. traitement de référence avec renouvellement de mini-terrasses et désherbage manuel ; 2. idem 1 sans renouvellement de mini-terrasses ; 3. idem 1 sauf désherbage avec un herbicide ; 4. idem 1 avec taille réduite des arbres d'ombrage. On a considéré trois périodes : P1 avant application des traitements, P2 les deux mois suivants traitement et P3 l'année suivante (2013). Les différences significatives entre les ratios de traitements/référence pour les trois périodes indiquent une augmentation du ruissellement et de la concentration en sédiments après renouvellement des mini-terrasses avec un effet toujours présent pour P3. Le désherbage avec un herbicide n'a pas montré d'influence claire. Le traitement avec taille réduite des arbres d'ombrage a réduit l'érosion pour les conditions d'humidité de sol > 30 % seulement.Le ruissellement superficiel, la concentration en sédiments et la perte en terre ont été mesurés à l'exutoire d'un petit bassin versant (31 ha, de pente moyenne de 60 %) en 2012 et 2013. Seules les pluies de hauteur supérieure à 5 mm (169 événements) ont produit du ruissellement et l'essentiel des volumes ruisselés a été produit lors des fortes averses (> 40 mm). Les coefficients de ruissellement ont été faibles (0.9 %) aux deux échelles en 2013. Ils ont atteint 2.44 % pour les parcelles et 0.9 % pour le bassin versant en 2013. L'écoulement de base était également faible pour le bassin versant (13-16 % de la pluie totale) avec une grande partie de la pluie (environ 20 %) perdue par percolation. La concentration moyenne en sédiments a été d'environ 1.65 g l-1 à l'échelle de la parcelle avec des valeurs maximales de 5.64 g l-1. La concentration moyenne en sédiments à l'échelle du bassin versant a été de 0.51 g l-1. La perte de sol annuelle a été de 0.73 et 0.36 t ha-1 an-1 à l'échelle parcellaire (tous traitements confondus) pour 2012 et 2013 respectivement et de 0.46 et 1.24 t ha-1 yr-1 à l'échelle du bassin versant pour les mêmes années.Le système caféier étudié a présenté une perte en terre modérée liée à une protection importante de la surface du sol par la végétation.
- Published
- 2015
48. Effets topographiques bidimensionnels en sismologie : vérification des coefficients simplifiés Eurocode 8 par une méthode en éléments-finis spectraux
- Author
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De Martin, Florent, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), and convention 2011 n° 2100472261 entre Ministère de l’écologie du développement durable et de l'énergie et le BRGM
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response spectrum ,butte ,topographic effects ,ridge ,méthode en éléments-finis spectraux ,tremblement de terre ,spectral element method ,versant ,pente ,[INFO.INFO-NA]Computer Science [cs]/Numerical Analysis [cs.NA] ,amplification factor ,effets topographiques ,coefficient d’amplification ,earthquake ,slope ,[SPI.GCIV.RISQ]Engineering Sciences [physics]/Civil Engineering/Risques ,séisme ,Eurocode 8 ,spectre de réponse ,[SDU.OTHER]Sciences of the Universe [physics]/Other - Abstract
National audience; The irregularity of the topography has an influence on earthquake ground motion. These effects are commonly called “topographic effects” and can amplify or de-amplify the bedrock ground motion. So far, these effects are included in the Eurocode 8 in a simplified way. The objective of this study is to check the validity of these simplifications using two-dimensional spectral finite element simulations (code EFISPEC http://efispec.free.fr). Following the analysis of the 500 simulations performed, it is shown that some EC8 coefficients are adjustable to better take into account these effects.; L’irrégularité de la topographique a une influence sur le mouvement sismique. Ces effets sont communément appelés « effets topographiques » et peuvent amplifier ou dé-amplifier le mouvement sismique enregistré au rocher. De nos jours, la prise en compte de ces effets topographiques dans les Eurocodes 8 est simplifiée. L’objectif de cette étude est de vérifier la validité de ces simplifications via des simulations en deux dimensions par une méthode en éléments-finis spectraux (code EFISPEC, http://efispec.free.fr). Après analyse des 500 simulations réalisées, il s’avère que certains coefficients sont ajustables pour une meilleure prise en compte de ces effets.
- Published
- 2015
49. Numerical and experimental studies of initial stresses in a slope
- Author
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Ngom, Mamadou, Sols, Roches et Ouvrages Géotechniques (IFSTTAR/GERS/SRO), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Communauté Université Paris-Est, Université Paris-Est, Hussein Mroueh, and STAR, ABES
- Subjects
Slope ,[SPI.OTHER]Engineering Sciences [physics]/Other ,Capteur de pression totale ,Contraintes initiales ,[SPI.OTHER] Engineering Sciences [physics]/Other ,Pente ,Pressure cells ,Initial stresses ,Finite elements ,Éléments finis - Abstract
Though the finite element method requires more input data than traditional methods, it is increasingly used for the design of geotechnical structures. Its use needs to define initial stresses, which are difficult to estimate or to measure.This thesis is a contribution to a better understanding of the initial stresses in a slope. It consists of both numerical and experimental studies.The numerical studies focus on two issues. At first, they assess the effects of initial stresses on the results of calculations using finite element methods. Secondly, the distribution of stresses in a slope is analysed, using CESAR-LCPC finite elements software. The influence of geological, geometric and mechanical parameters on the state of stresses is studied.The objective of the experimental studies is to measure the lateral stresses in a slope using push-in total stress cells. The stresses are measured continuously in order to estimate the stresses in the ground after the dissipation of the effects of installation procedure. Laboratory tests made at CEREMA in Aix-en-Provence include “K0 oedometer tests” which provide measures of the coefficient of earth pressure at rest. The difficulties associated with the measurement of the coefficient of earth pressure at rest and the parameters that can influence it (type of soil, geometry of soil mass, water content ...) are discussed, Bien que son utilisation requière plus de paramètres que les méthodes traditionnelles la méthode des éléments finis est de plus en plus utilisée pour la conception, des ouvrages géotechniques. Son utilisation nécessite notamment la définition du champ initial des contraintes qui reste très difficile à estimer et mesurer.Ce travail de thèse est une contribution à une meilleure connaissance de l'état initial des contraintes dans une pente. La thèse comporte des études numériques et expérimentales.Les études numériques évaluent, dans un premier temps, la variation des résultats des calculs par la méthode des éléments finis induite par l'incertitude sur l'état initial des contraintes. Dans un deuxième temps, la distribution des contraintes suite à la modélisation d'une pente au moyen du logiciel CESAR-LCPC est étudiée. L'influence des paramètres géologiques, géométriques et mécaniques sur le champ initial des contraintes est étudiée.L'objectif de l'étude expérimentale est de mesurer, avec des capteurs de pression totale fonçables, les contraintes horizontales dans une pente. La campagne expérimentale opte pour un suivi de la relaxation des contraintes horizontales jusqu'à la stabilisation des mesures. Des essais en laboratoire, réalisés au CEREMA à Aix en Provence, incluent des essais œdométriques à mesure de K0 qui donnent des valeurs du coefficient de pression des terres au repos mesuré en laboratoire. Les difficultés liées à la mesure du coefficient de pression des terres au repos et les paramètres qui peuvent l'influencer (nature des terrains, variations de teneur en eau, etc.) sont discutés
- Published
- 2015
50. Les effets socio-économiques et paysagers du système coopératif viticole en territoires de montagne
- Author
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Fabio Zottele, Marius Chevallier, Etienne Delay, Éric Rouvellac, Laboratoire de Géographie Physique et Environnementale (GEOLAB), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Université Clermont Auvergne (UCA)-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Chevallier-Jacquemin, Marius
- Subjects
2. Zero hunger ,0106 biological sciences ,Physical geography ,010504 meteorology & atmospheric sciences ,wine cooperative ,[SHS.GEO] Humanities and Social Sciences/Geography ,Geography, Planning and Development ,pente ,agent-based modeling ,vineyard landscape ,[SHS.GEO]Humanities and Social Sciences/Geography ,15. Life on land ,modélisation à base d'agents ,01 natural sciences ,[SDE.ES]Environmental Sciences/Environmental and Society ,GB3-5030 ,010601 ecology ,coopérative viticole ,paysage viticole ,Geography. Anthropology. Recreation ,slope ,[SDE.ES] Environmental Sciences/Environmental and Society ,0105 earth and related environmental sciences ,Earth-Surface Processes - Abstract
Dans une économie de mondialisation accrue des échanges, le vin tient une place privilégiée. Le système de coopérative vitivinicole, dans un contexte de viticulture de fortes pentes comme à Banyuls sur Mer (France) ou dans le Val di Cembra (Italie), constitue un laboratoire privilégié pour étudier des opportunités qui modifient des équilibres socio-économiques et paysagers précaires. Pour comprendre, et parfois prévoir, les évolutions des dimensions socio-économiques et paysagères du territoire lié aux coopératives, nous avons essayé de modéliser à travers un système multi agents (SMA) les comportements des acteurs intervenant dans la production vitivinicole dans un système coopératif. Ceci nous permet d’analyser les impacts du système coopératif sur la socio économie (inégalités de revenus et taux de survie) et les paysages (part de la viticulture, notamment dans les espaces en fortes pentes) des territoires considérés. Nous montrons que la coopérative joue un rôle de stabilisateur socio-économique et paysager du territoire. In an economy of increased globalization and trade, wine holds a privileged place. The wine cooperative system in vineyards in mountain regions, such as in Banyuls-sur-Mer, France and the Val di Cembra, Italy, offers a privileged context for studying the opportunities for individual action that affect precarious socio-economic balances. To understand, and sometimes predict, changes in the socio-economics and landscapes of a region due to cooperatives, we have used a multi-agent system (MAS) to model the behavior of the actors involved in wine production in a cooperative. This model analyses cooperative systems’ impact on socio-economic factors (income inequality and the rate of business failure) and landscapes (percentage of total land as vineyards, particularly in steep areas) of the regions considered. The findings show that cooperatives play a role of socio-economic and landscape stabilizer in these regions.
- Published
- 2015
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