104 research outputs found

    Estimation de la vulnérabilité d'une structure soumise à un affaissement minier

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    En 1996, la ville d'Auboué, située en Meurthe et Moselle, dans le bassin ferrifère lorrain subit les conséquences d'un affaissement minier. 20 années s'étaient écoulées depuis le dernier événement du même ordre qui avait affecté la ville de Crusnes en 1977 Depuis, quatre autres affaissements se sont produits dans cette région, provoquant de sérieuses dégradations du bâti et des infrastructures. Le bassin ferrifère lorrain a été exploité depuis la seconde moitié du 19e siècle. A partir de ces années et jusqu'aux années 1870, les mines ont été exploitées par des méthodes du type "chambres et piliers abandonnés" qui consistaient à laisser en place du minerai sous forme de piliers, permettant de supporter le poids des terrains sus-jacents. Supposés stables à long terme, ces exploitations ont été abandonnées. Diverses raisons permettent d'expliquer l'effondrement à moyen et long terme des piliers et des terrains sus-jacents

    Comparison of building damage assessment methods for risk analysis in mining subsidence regions

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    The occurrence of subsidence phenomena in urban regions may induce small to severe damage to buildings. Many methods are provided in the literature to assess buildings damage. Most of these methods are empirical and use the horizontal ground strain as a subsidence intensity in the vicinity of a building. Application and comparison of these methods with a case study is the main objective of this paper. This comparison requires some harmonization of the existing methods and the development of a software, which combines the subsidence hazard prediction, the damage evaluation methods and a database of buildings with structural parameters as well as the geographical coordinates of the buildings An additional results is the development of a method for the prediction of the horizontal ground strain in the vicinity of each building. Results are given as a map of damaged buildings for the case study and the different existing methods with some statistical calculations such as the mean and the standard deviation of damage in the city. Comparison of these results allows identification of the “safer” method that give the higher mean of damage. The comparison of the calculated results and observed damage in Lorrain region show that, the Dzegeniuk et al. methods is more realistic in comparison of the other empirical methods

    Development of building vulnerability functions in subsidence regions from empirical methods

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    The extraction of ores and minerals by underground mining often causes ground subsidence phenomena. In urban regions, these phenomena may induce small to severe damage to buildings. To evaluate this damage, several empirical and analytical methods have been developed in different countries. However, these methods are difficult to use and compare due to differences in the number of criteria used (from 1 to 12). Furthermore, the results provided by damage evaluation may be significantly different from one method to another. The present paper develops vulnerability functions based on a concept that has been applied in other areas, such as earthquake engineering, and that appears to be a more efficient way to assess building vulnerability in undermined cities. A methodology is described for calculating vulnerability functions in subsidence zones using empirical methods. The first part of the paper focuses on existing empirical methods for damage evaluation, and selected necessary improvements or modifications are justified. The second part focuses on the development of a building typology in subsidence zones and its application in the Lorraine region, where many villages are subject to subsidence problems due to iron-ore mining. The third section describes and discusses the adopted methodology for determining vulnerability and fragility functions or curves. Finally, vulnerability functions are tested and validated with a set of three subsidences that occurred in Lorraine between 1996 and 1999

    Development of building vulnerability functions in subsidence regions from analytical methods

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    Ore and mineral extraction by underground mining often causes ground subsidence phenomena, and may induce severe damage to buildings. This paper develops vulnerability and fragility functions to assess building damage in the context of mining subsidence hazards, comparable to functions used for other hazards. These functions are based on existing analytical methods for damage assessment. They take into account both the uncertainty of the geometric and mechanical parameters of the building and the soil–structure interaction phenomena that may have a critical influence on the building loading. The present paper discusses the methodology used to determine these functions, and the analytical method for damage evaluation is described. The second part is a detailed application of the methodology for a masonry building with or without reinforcement, for which both vulnerability and fragility functions are calculated. Finally, vulnerability functions are tested and validated with a set of three subsidences that occurred in Lorraine (France) between 1996 and 1999

    Vulnerability assessment for mining subsidence hazard

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    International audienceAfter the last mining subsidence events, which occurred in the iron-ore field in Lorraine (France) in 1996, 1997 and 1999, and because of the thousand hectares of undermined areas, the assessment of vulnerability of buildings and territories became necessary for risk management. The ten last years highlight evolutions of the vulnerability concept and its assessment method between the first risk management decisions and current risk assessment. These evolutions reveal a lot about the complexity of the vulnerability concept and about difficulties to develop simple and relevant methods for its assessment. The objective of this paper is to present this evolution and to suggest different improvements compared to other concepts and methods developed in other countries (USA, Poland...) and for other hazards (flood, industrial...). These improvements take into account more various kinds of elements in the vulnerability meaning (buildings, people, roads, public facilities and public functions) as well as they deal with method of assessment in relation to the subsidence intensity and vulnerable elements.Depuis les affaissements miniers survenus en Lorraine en 1996, 1997 et 1999, et en raison des milliers d'hectars sous-minés, l'évaluation de la vulnérabilité des habitations et des territoires est devenu une nécessité pour permettre une meilleure prévention des risques. Les dix années écoulées depuis les premières décisions prises en réaction au risque d'affaissement minier montrent une évolution importante des méthodes employées. Ces évolutions sont révélatrices de la complexité du concept de vulnérabilité et de la difficulté à trouver des méthodes pertinentes et opérationnelles pour l'évaluer. Cet article a pour objectif de présenter cette évolution et de donner des perspectives d'amélioration au vu des méthodes employées dans d'autres pays (Etats-unis, Pologne) et vis-à-vis d'autres aléas (sismique, inondation, accidents industriels). Ces perspectives portent sur les différents enjeux qui contribuent à la vulnérabilité (personnes, bâtiments, infrastructures, équipements publics...) et sur les méthodes de caractérisation de la vulnérabilité en fonction des enjeux et de l'intensité de l'affaissement

    An extension of analytical methods for building damage evaluation in subsidence regions to anisotropic beams

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    Ore and mineral extraction by underground mining often causes ground subsidence phenomena, and may induce severe damage to buildings. Analytical methods based on the Timoshenko beam theory is widely used to assess building damage in subsidence regions. These methods are used to develop abacus that allow the damage assessment in relation to the ground curvature and the horizontal ground strain transmitted to the building. These abacuses are actually developed for building with equivalent length and height and they suppose that buildings can be modelled by a beam with isotropic properties while many authors suggest that anisotropic properties should be more representative. This paper gives an extension of analytical methods to transversely anisotropic beams. Results are first validated with finite elements methods models. Then 72 abacuses are developed for a large set of geometries and mechanical properties

    Etude de la vulnérabilité du bâti soumis aux conséquences des affaissements miniers

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    International audienceRecent mining subsidences that took place at the end of the 1990s in the iron-ore field cause building damage and put the emphasis on some problems. In particular, is it possible to estimate building vulnerability which is located on ground which may subside? Previous works in this domain, in addition with an own statistical study performed on observations collected in the iron-ore field, a new methods is offered. This is inspired by well-known seismic methods in order to increase its accuracy and pertinence.Les récents affaissements miniers qui se sont produits à la fin des années 90 dans le bassin ferrifère lorrain ont été à l'origine d'importantes dégradations du bâti. L'existence d'ouvrages miniers abandonnés en grande quantité nécessite d'élaborer des méthodes permettant d'évaluer la vulnérabilité des enjeux. A partir des travaux déjà réalisés dans ce domaine, ainsi que d'une analyse de données sur les dégradations observées dans le bassin ferrifère lorrain, une nouvelle approche est proposée. Cette approche s'inspire des méthodes employées dans le domaine sismique pour aboutir à une prise en compte de l'intensité du phénomène et de la diversité des constructions de manière plus pertinente et précise

    The Take into account of soil-structure interaction phenomena to study mining subsidence consequences on buildings

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    The authors used a numerical finite element software for several modellings to study soil-structure interaction phenomena which occur during mining subsidences. We broke down the ground movements into several basic movements to highlight the impact and relative importance of each other (ground curvature and horizontal strain). We elaborate synthetic schemes of the ground and structure behaviour which improve the traditional apprehension of phenomena.Les auteurs ont utilisé un code de calcul aux éléments finis pour étudier les phénomènes d'interaction sol-structure qui ont lieu durant les affaissements miniers. Nous avons distingué les différents mouvements des terrains (déformation horizontale et courbure) afin de mettre en évidence leur impacte respective. Nous avons élaboré des schémas synthétiques, du comportement des terrains et des structures, qui permettent d'améliorer la conception traditionnelle des phénomènes en place

    Etude des conséquences des affaissements miniers sur le bâti par la modélisation numérique

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    Mining subsidence generates great displacements of the ground surface which may be responsible of building damage. Estimation of ground displacements are well-known but their transfer to the structure need more studies. We will first present different numerical strategies for the take into account of soil-structure interaction. Then we will present a global finite element model which allowed us to study behaviour of different kind of structures. In particular we show some results for a rigid structure (raft) and for a soft one (framed structure).Les affaissements miniers, en provoquant d'importants déplacements de la surface des terrains peuvent être à l'origine de dégradations dans les structures. Si la prévision des mouvements du terrain est bien acquise, celle de leurs transferts aux ouvrages l'est nettement moins. Après une étude des différentes possibilités de modélisation du problème pour prendre en compte les phénomènes d'interaction sol-structure, nous présentons un modèle global de type éléments finis. Ce dernier nous a permis d'étudier le comportement de différents types de structures. En particulier, nous montrons les résultats de calculs pour une structure rigide (radier) et une autre plus souple (portique)
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