Evaluation de la performance des barrages basée sur la formalisation de l'expertise
… de Génie Civil, La …, 2006
RÉSUMÉ. L'évaluation de l'état et de la sécurité des barrages repose essentiellement su... more RÉSUMÉ. L'évaluation de l'état et de la sécurité des barrages repose essentiellement sur la connaissance d'experts qui ont développé, au fil du temps, des stratégies de mesure, d'évaluation globale et de décision. Or, cette connaissance n'est pas toujours formalisée. ...
Diagnostic de barrage et analyse de vieillissement de risque: élaboration des méthodes pour soutenir le jugement expert
International audienceDiagnosis and risk analysis are essential to ensure the safety of dams. Dam... more International audienceDiagnosis and risk analysis are essential to ensure the safety of dams. Dam Specialist Engineers have useful methods available to help them in their task: physical modelling for assessing dam stability, statistical analysis of dam monitoring data and, more recently, functional modelling for operational safety analysis. However, an expert's judgment is necessary when the works are complex and unique, when data are imprecise or insufficient and when preliminary diagnosis or detailed analysis are being made. Using their experience and knowledge, dam specialist engineers are able to provide the recommendations to address specific problems. The authors propose methods to support expert diagnosis and risk analysis which capitalise on the expert's knowledge and feedback. Their approach is threefold, (i) an ageing functional model based on the Failure Mode and Effect Analysis (FMEA) method using a causal graph representation of ageing scenarios leading to loss ...
Formulation des bases d'une méthode semi-probabiliste aux états-limites pour la justification des barrages poids en béton ou maçonnerie
In France like in abroad, there are many regulations or recommendations regarding gravity dams. N... more In France like in abroad, there are many regulations or recommendations regarding gravity dams. None of these regulations takes into account semi-probability safety format wich is currently used in civil engineering and in quantifing risks. This paper presents the principal determinist verifications and proposes a limit state semi-probability method format for concrete or masonry gravity dams.En France comme à l'étranger, il existe de nombreux réglements ou recommandations relatifs au dimensionnement des barrages poids. Toutefois, aucun d'eux ne prend en compte la sécurité au format semi-probabiliste, connu dans le génie civil traditionnel et bien adapté à la quantification des risques. Cet article expose les critères de dimensionnement rencontrés dans les méthodes déterministes et formule les bases d'une méthode semi-probabiliste aux états limites pour la justification des barrages poids en béton ou en maçonnerie
Filtre géotextile du barrage de Torcy-Vieux (71) : prélévements et analyses
The Torcy-Vieux dam is a homogeneous earthfill dam which was built around 1800. There were severa... more The Torcy-Vieux dam is a homogeneous earthfill dam which was built around 1800. There were several phases of construction interrupted by incidents and repairs. In 1987, the last one consisted in logging trees on the downstream slope, boring 12 drainage wells on the downstream toe and building a downstream shoulder of about 4 m height, with drain wrapped around with geotextile filters. In 1997 an inspection operation noticed seepages on the superior part of the downstream slope. A more acute analysis came to the conclusion of a high risk of internal erosion and clogging of the drain geotextile filters. In august 1998, the pulling down operation of the downstream shoulder gave opportunity to take samples and do laboratory tests. Their results are given in this study report.Le barrage de Torcy-Vieux (Saône et Loire) est un barrage en remblai, construit vers 1800. Son histoire se caractérise par une construction en plusieurs étapes et une succession d'incidents et de réparations. Le...
Relation entre l'âge et le diamètre de racines prélevées sur des digues de protection contre les inondations
National audienceLe but de cette étude est d'évaluer l'existence d'une relation entre... more National audienceLe but de cette étude est d'évaluer l'existence d'une relation entre le diamètre des racines et leur âge. Cela afin de pouvoir mettre en évidence l'existence de seuils critiques en termes d'âge des souches. Au delà d'une dimension critique, dépendante des matériaux de la digue, les racines deviennent dangereuses pour l'ouvrage. L'évaluation de la dimension des racines étant complexe par rapport à la mesure de l'âge de l'arbre, ces seuils constitueront un outil d'aide à la gestion de la végétation arborescente sur les digues
Détection d'échantillons de racines enterrés par mesures électriques
International audienceTrees growing on earth dikes generate safety problems and reduce dikes dura... more International audienceTrees growing on earth dikes generate safety problems and reduce dikes durability. Root systems generate internal and external erosion risks which can be important on wooded dikes. The aim of this study was to differentiate various root samples of trees rooted in dikes by geo-electrical measurements. Before proceeding to roots detection in situ, it is necessary to make tests in laboratory. The objective of this experiment is to characterize exactly the electrical signal of buried roots according to root samples orientation and depth and to materials type. Root samples were buried in plastic boxes in different type of dyke materials. Electrical conductivity measurements were carried out on buried root samples with their complete structure
Architecture des systèmes racinaires implantés dans des digues en terre
International audienceTrees growing on earth dikes generate safety problems and reduce dike durab... more International audienceTrees growing on earth dikes generate safety problems and reduce dike durability. Root systems generate internal and external erosion risks which can be important on dikes wooded for a long time. Erosion risks increase with tree age and stand density. The aim of this study is to analyse root systems characteristics of trees rooted in canal dikes and flood protection dikes. Root systems structure and morphology depend on species and materials. On various species studied, different types of roots can be observed. Short and long roots are characterized by differences in diameter decrease, branching frequency and inclination. A root typology is determined
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