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Статті в журналах з теми "Voussoirs":

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Galletti, Sara. "Philibert de L’Orme’s Dome in the Chapel of the Château d’Anet: The Role of Stereotomy." Architectural History 64 (2021): 253–84. http://dx.doi.org/10.1017/arh.2021.11.

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ABSTRACTThe coffered dome designed by Philibert de L’Orme (1514–70) for the chapel of the Château d’Anet in northern France between 1549 and 1552 is a masterpiece of stereotomy — the stone vaulting technique characterised by the custom cutting (or dressing) of a vault’s components or voussoirs. The dome was executed by first individually dressing its large voussoirs, so that they would fit one another precisely, and then dry assembling them like the pieces of a three-dimensional jigsaw puzzle. The spiralling ribs that form the coffers added a layer of complexity to the work, for they are embedded in the voussoirs; thus the exact shape and position of the rib sections belonging to each voussoir had to be calculated precisely before dressing to ensure that, after assembling, they would form the correct pattern over the vault’s surface. The dome’s execution method continues to baffle historians, in particular with regard to the transfer of the complex pattern formed by the ribs on to the templates used by the stonecutters to shape the voussoirs. Based on a new 3D laser scan of the dome and on the analysis of late medieval and early modern stereotomic practices and theories, this article offers a new interpretation of the methods that de L’Orme adopted at Anet and of their significance within the panorama of sixteenth-century architectural practice and theory.
2

Abdulhameed, Ali A., and AbdulMuttalib I. Said. "Experimental Investigation of the Behavior of Self-Form Segmental Concrete Masonry Arches." Fibers 7, no. 7 (July 2, 2019): 58. http://dx.doi.org/10.3390/fib7070058.

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This research aims to introduce a new technique—off-site and self-form segmental concrete masonry arches fabrication, without the need of construction formwork or centering. The innovative construction method in the current study encompasses two construction materials forms the self-form masonry arches, wedge-shape plain concrete voussoirs, and carbon fiber-reinforced polymer (CFRP) composites. The employment of CFRP fabrics was for two main reasons: bonding the voussoirs and forming the masonry arches. In addition, CFRP proved to be efficient for strengthening the extrados of the arch rings under service loadings. An experimental test was conducted on four sophisticated masonry arch specimens. The research parameters were the Keystone thickness and the strengthening of the self-form arch ring at the intrados. The major test finding was that the use of thicker Keystone alters the behavior of the self-form arch and considerably increases the load carrying capacity by 79%. Partial strengthening of the intrados with CFRP fabrics of typical arch ring Keystone resulted considerable increase in the debonding load of fabrication CFRP sheets by 81%, increase in the localized crushing load by 13% and considerably increase voussoir sliding load by 107%.
3

de Azambuja Varela, Pedro, and José Pedro Sousa. "Variable Casting of Voussoirs for a Stereotomic Shell." Nexus Network Journal 20, no. 3 (April 30, 2018): 627–44. http://dx.doi.org/10.1007/s00004-018-0382-z.

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Harris, Roland B. "RECONSTRUCTING THE ROMANESQUE CLOISTER OF NORWICH CATHEDRAL." Antiquaries Journal 99 (September 2019): 133–59. http://dx.doi.org/10.1017/s0003581519000118.

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Works to the south side of the Gothic cloister at Norwich Cathedral in 1900 produced a series of finely sculpted double-capitals, which have long been identified as deriving from the Romanesque predecessor that was progressively demolished and replaced in 1297–1430. Additional discoveries in 1900 included twelfth-century voussoirs and jamb stones, which probably came from one of the larger doorways – perhaps to the chapter house – that opened off the cloister. These fragments have attracted considerable interest since 1900, almost entirely focused on art historical analysis of the subjects, style and date of the historiated double-capitals. Discovery of further fragments from the Romanesque cloister during works to the easternmost bay of the south walk (Bay 15) in 2018, however, allows us to understand more of its architecture. Although lacking the impressiveness of the earlier finds, these newly revealed sculpted stones include voussoirs and a shaft from the cloister arcades, and allow reconstruction of the overall form of the twelfth-century cloister. Moreover, the discovery of the use of calc-sinter – a faux marble sourced from the Eifel aqueduct – for the shafts of the arcades reveals that the Romanesque cloister had a hitherto entirely unsuspected lavishness.
5

Pomares, Juan Carlos, Antonio González, and Pascual Saura. "Simple and Resistant Construction Built with Concrete Voussoirs for Developing Countries." Journal of Construction Engineering and Management 144, no. 8 (August 2018): 04018076. http://dx.doi.org/10.1061/(asce)co.1943-7862.0001532.

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Bryant, Richard. "A Carved Romanesque Springer with Voussoirs in Church House, Gloucester Cathedral." Journal of the British Archaeological Association 170, no. 1 (January 2017): 180–95. http://dx.doi.org/10.1080/00681288.2017.1366627.

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Quiertant, Marc, François Toutlemonde, and Jean-François Seignol. "Etude d'une alternative en béton de fibres pour voussoirs de tunnel." Revue Française de Génie Civil 6, no. 5 (January 2002): 763–75. http://dx.doi.org/10.1080/12795119.2002.9692401.

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Baraldi, Daniele, Giosuè Boscato, Claudia Brito de Carvalho Bello, Antonella Cecchi, and Emanuele Reccia. "Discrete and Finite Element Models for the Analysis of Unreinforced and Partially Reinforced Masonry Arches." Key Engineering Materials 817 (August 2019): 229–35. http://dx.doi.org/10.4028/www.scientific.net/kem.817.229.

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In this work the behavior of masonry arches, without reinforcement and with partial reinforcement, is investigated by means of three different numerical models. The first one is a Discrete Element model based on rigid blocks, and elastic-plastic interfaces; the second one is a standard heterogeneous Finite Element Model, which is adopted for a detailed micro-modelling of arch voussoirs, joints, and reinforcements. The third model is analytic-numerical, and it is adopted for validating the other numerical results. The aim of the work is the comparison and validation of the numerical Finite and Discrete Element models for the correct simulation of masonry arch behavior, together with the evaluation of the effectiveness of these models in simulating the behavior of the partially reinforced arch.
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Saad Abdel Naby, Heba Mahmoud. "The Treatment of the Architectural Unit above Openings of the Mamluk and Ottoman Facades in Cairo." Journal of Islamic Architecture 3, no. 2 (September 3, 2014): 82. http://dx.doi.org/10.18860/jia.v3i2.2541.

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<p>The facades of the Mamluk buildings have a common characteristic feature which is the use of lintels, nafis and relieving arches above doors and windows. The three elements together formed a unit with an important architectural function on the façades. This unit was also treated as a focal point of the façade. Therefore, it was richly decorated with floral and geometric decorations and was usually made of colored marble, joggles voussoirs or carved stones. As a result, that unit attracted the attention of pedestrians and added to the beauty of the façade.</p> During the Ottoman period the same unit was used on facades, however, due to financial and political reasons, the materials used differed and the decorations became modest. Nonetheless, the decoration of the lintel, nafis and relieving arch managed to mark the Ottoman facades with a different identity.
10

Hill, Nick, and Andrea Kirkham. "TWELFTH-CENTURY INTERIOR DECORATION: A DISCOVERY AT OAKHAM CASTLE, RUTLAND." Antiquaries Journal 98 (September 2018): 115–43. http://dx.doi.org/10.1017/s0003581518000057.

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A decorative scheme applied to the internal gable wall at the ‘high’ end of the hall of Oakham Castle, in Rutland, has been the subject of recent investigation, with the removal of later over-painting. Analysis indicates that the scheme is original Romanesque work dating from the 1180s, an exceptional survival for a secular building. Very unusually, the decoration was produced with self-coloured plaster rather than paint. The scheme, of which quite extensive sections survive, consisted of a large semi-circular arch with voussoirs (similar to the hall’s main stone arcade), and a lattice pattern simulating opus reticulatum in the tympanum below. The pattern was created by laying white lime strips over a buff-coloured plaster background. The only comparable example yet identified – at Chepstow Castle, in Monmouthshire – is on a smaller scale and a century earlier. The scheme seems to have survived because the interior of the hall has been little disturbed, with a tradition since the fifteenth century of displaying outsized horseshoes on the walls.

Дисертації з теми "Voussoirs":

1

Trad, Rim. "Étude du comportement des revêtements de tunnels creusés au tunnelier : modélisation numérique du contact entre voussoirs." Thesis, Université de Lille (2018-2021), 2021. https://pepite-depot.univ-lille.fr/ToutIDP/EDENGSYS/2021/2021LILUN036.pdf.

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Le creusement des tunnels en milieu urbain a connu un essor considérable ces dernières décennies, avec des projets de plus en plus ambitieux. L’un des enjeux majeurs des ingénieurs et d’assurer à la fois la sécurité des travaux de construction et celle des avoisinants, souvent dans un contexte de plus en plus complexe. Dans ce cadre-là, les ingénieurs cherchent à améliorer leur modèle de calcul de l’ouvrage souterrain, qui en plus de l’aspect tridimensionnel et fortement non linéaire, doit prendre en compte le comportement des éléments de l’ouvrage de soutènement, constitué principalement de voussoirs formant l’anneau des tunnels par assemblage mécanique en eux. Dans certaines configurations, la connaissance du comportement des liaisons entre voussoirs est primordiale, car elle peut influencer de manière substantielle les méthodes de calcul.Le cadre de cette thèse s’inscrit dans cet objectif de mieux comprendre et de proposer des améliorations aux outils de calcul des soutènements des tunnels revêtus par des anneaux de voussoirs.Le premier objectif de ce travail est d’évaluer la fiabilité des approches existantes dans la littérature sur l’influence de la présence des joints dans la structure d’un tunnel. Le deuxième objectif est de proposer une modélisation numérique pratique du joint avec une loi de comportement tenant compte de toutes les non-linéarités des paramètres matérielles et géométriques qui influent sur le comportement du joint.Une étude comparative numérique des différentes méthodes existantes dans la littérature est d’abord abordée. Sur la base de données issues de la littérature, il est noté que les différentes méthodes fonctionnent mais à condition de pouvoir les calibrer à des données de chantier parfois indisponibles. Une limitation des méthodes existantes est donc observée, d’où la nécessité de décrire le comportement du joint de la manière la plus pertinente en fonction de la géométrie et des caractéristiques des joints.Le deuxième objectif de la thèse est de proposer un modèle de calcul par élément fini tridimensionnel capable de prendre en compte le comportement local complexe des joints à travers une approche globale, sur la base d’essais de flexion quatre points de deux voussoirs et d’un joint longitudinal. Une étude paramétrique est appliquée sur cette simulation pour étudier l’influence des paramètres reliés aux non-linéarités matérielles et à la géométrie de l’interface sur le comportement du joint. Une loi de comportement du joint longitudinal (Moment en fonction de rotation) non-linéaire est proposée et validée avec les essais expérimentaux. Les calculs sont également étendus au comportement non linéaire du béton, avec la prise en compte de la plasticité et l’endommagement du béton.La dernière partie vise à fournir une approche pratique pour modéliser le macroélément du joint longitudinal par éléments finis unidimensionnels. Cette méthode simplifiée est capable de prendre en compte le comportement local complexe (prise en compte de toutes les non-linéarités des paramètres matérielles et géométriques qui influent sur le comportement du joint : Nombre de boulons, épaisseur de voussoir, chargement, l’endommagement, résistance de joint...) par une approche globale. La fiabilité du modèle proposée a été confirmée par de bonnes correspondances entre les résultats obtenus par simulation et le comportement observé des essais expérimentaux
Tunneling in urban areas has grown considerably in recent decades, with increasingly ambitious projects. One of the major challenges for engineers is to ensure both safety during the construction work and its surrounding in an increasingly complex context. Engineers seek to improve their calculation models of the underground structure, beyond the three-dimensional and highly non-linear aspects, most take into account the behavior of the support structure elements, which mainly consist of segments forming the ring of the tunnels by mechanical assembly within them. In certain cases, knowing the detailed behavior of the joints connecting the segments is essential, as it can substantially influence the calculation methods.The framework of this thesis is in line with the objective of better understanding and proposing improvements to the calculation tools for tunnel lining with segmental rings.The first objective of this work is to evaluate the reliability of existing approaches in the current literature with regards to the influence of joints in the tunnel structure. The second objective is to propose practical numerical modeling for the joint with a behavioral law that takes into account all the non-linearities of the material and geometrical parameters that influence the joint behavior.A comparative numerical study of the existing methods is done and introduced in the literature review. Based on the data gathered from the study, it has been noted that the different methods generally work well, but on condition that they can be calibrated to data which is sometimes unavailable. Therefore, a limitation of the existing methods is observed, hence the need to describe the joint behavior in the most relevant way according to geometry and joint characteristics.The second objective is to propose a three-dimensional finite element model capable of taking into account the complex local behavior of the joints through a global approach, based on four-point bending tests of two segments and a longitudinal joint. A parametric study has been done on this model to study the influence of parameters related to material non-linearities and interface geometry on the joint behavior. A non-linear longitudinal joint behavior law (Moment versus rotation) is proposed and validated with experimental tests. The calculations are also extended to the non-linear behavior of concrete, taking into account the plasticity and damage on the concrete.The last part aims at providing a practical approach to model the longitudinal joint macro-element by one-dimensional finite element. This simplified method takes into account the complex local behavior, including the non-linearities of the material and geometrical parameters that influence the joint behavior (number of bolts, the thickness of the segment, loading, damage and joint resistance...) through a global approach. The reliability of the proposed model was confirmed by good correspondence between the simulation results experimental tests
2

Bouafia, Youcef. "Résistance à l'effort tranchant des poutres en béton à precontrainte exterieure : étude experimentale et calcul à la rupture." Châtenay-Malabry, Ecole centrale de Paris, 1991. http://www.theses.fr/1991ECAP0198.

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La précontrainte extérieure se développe de plus en plus actuellement. Elle présente des avantages par rapport à la précontrainte intérieure classique pour le contrôle des câbles en oeuvre et leur remplacement éventuel. L'étude de la résistance à l'effort tranchant est abordée par les deux aspects suivants: a) dans le cas des poutres monolithes; la possibilité de formation d'un mécanisme en treillis avec liaison ponctuelle entre la membrure tendue (le câble extérieur) d'une part, et les autres éléments du treillis : montants (armatures transversales) et diagonales (bielles de béton comprimées) d'autre part; b) la transmission de l'effort tranchant dans un joint ferme (en phase de construction) et ouvert par flexion (à l'état limite ultime) pour les poutres construites par voussoirs préfabriqués. Un programme d'essais a été alors lancé au CEBPT sur des poutres monolithes (pour comparer le cas ou le câble est intérieur adhérent au béton et le cas ou le câble est extérieur) et, parallèlement sur des éléments de poutres à voussoirs préfabriqués. Pour ce dernier mode de construction, des essais de cisaillement ont été réalisés sur des joints fermes et sur des joints ouverts par flexion. Les résultats d'essais ont permis la mise au point d'un modèle de calcul de la résistance à l'effort tranchant des poutres à précontrainte extérieure en adaptant un modèle empirique. Corrélativement, une méthode de calcul de la résistance au cisaillement parallèlement au plan des joints entre voussoirs préfabriqués est proposée.
3

Ran, Jingqiang. "Voussoir beam stability analysis for the jointed roof in stratified rock mass." Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335149.

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Allison, David Paul. "An evaluation of the mass behaviour of hard sedimentary strata adjacent to large underground openings." Thesis, University of Exeter, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294440.

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Josefsson, Elaina. "Voussoir Bridges : Refining the cornerstone of art education - the effect of culture shock on intercultural learning." Thesis, Konstfack, Institutionen för Bildpedagogik (BI), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-4634.

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6

Shabanimashcool, Mahdi. "Numerical modelling of the longwall mining and the stress state in Svea Nord Coal Mine." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for geologi og bergteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20255.

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This thesis presents numerical and analytical investigation of the geomechanics underlying longwall mining. It was tried out to study the disturbances induced by longwall mining in nearby rocks and their influence on the stability of the gates, pillars and main tunnels of longwall mines. The thesis consists of two major parts: numerical and analytical investigations. The study site is the Svea Nord coalmine, Svalbard, Norway. A novel algorithm was proposed for numerical simulation of the longwall mining process. In the proposed algorithm progressive cave-in and fracturing of the roof strata, consolidation of the cave-in materials and stress changes are simulated in detail. In order to outline the caved-in roof rocks a criterion based on maximum principal strain (in tension) was used. The critical tensile strain of roof cave-in was determined through back-calculation of the surface subsidence above a longwall panel at the mine. The results of the simulations were then used to analyse stress changes induced by longwall mining and the stability of gates. The simulations revealed that the stability of the gates and the loading to the rock bolts are closely related to the width of the chain pillars. With slender pillars, shear displacements along weak interlayers and bedding planes result in heavy loading to the rock bolts. Therefore, the locations of weakness zones should be taken into account in rock bolt design. The developed algorithm was implemented to study the loading and stability of the barrier pillar of the mine. The barrier pillars protect the main tunnels and border area of the mine from disturbances induced by longwall mining in the panels. The simulations show that the stresses in the barrier pillars fluctuate up and down during mining because of periodic cave-in events behind the longwall face. A failure zone of about 12 m exists in the wall of the barrier pillars. A large portion of the barrier pillar is still intact and is, thus, capable of protecting the border area. The results of the detailed simulations of longwall mining via the developed algorithm were, also, implemented in a large-scale numerical model. The model consists of all of the longwall panels and the border area of the mine. It is intended that the coal in the border area on the other side of the longwall panels will be mined after completion of the longwall mining. There is concern about how the longwall mining affects the stress state in the border area and how stress changes would affect future mining in the border area. A failure zone of about 20 m developed in the wall of the main tunnels on the side of the border area after all the longwall panels were mined out. The stress state in the remaining portion of the border area remains unchanged. Therefore, it will be possible to mine the border area in the future. In order to investigate the roof strata cave-in mechanism in detail a discontinuous numerical simulation of roof cave-in process was conducted by UDEC code. The block size in the roof strata and the mechanical parameters of the discontinuities were obtained through back-calculations. The back-calculations were conducted with a statistical method, Design of Experiment (DOE). Numerical simulations revealed that jointed voussoir beams formed in the roof strata before the first cave-in. Beam bending results in stress fluctuations in the roof strata. The maximum deflection of a roof stratum at the study site before the first cave-in is about 70% of the stratum thickness. The simulations and field measurements show no periodic weighting on the longwall shields in this mine. Numerical sensitivity analyses show, however, that periodic weighting may occur in strong roof strata. Roof strata with a high Young’s modulus and large joint spacing are not suitable for longwall mining. The maximum sustainable deflection of the roof strata before cave-in depends upon the horizontal in-situ stress state. It slightly increases with the in-situ horizontal stress in the stratum beams, but the horizontal stress would increase the possibility of rock-crushing in deflected roof beams. The implemented numerical method would be useful in assessment of the cavability of the roof strata and in selection of longwall shields with adequate load capacity. As shown through discontinuous numerical simulations, the roof strata above the underground opening constructed in the stratified rocks form voussoir beams. The stability of those beams is the major concern in the study of the gate stability and roof cave-in assessment in the longwall panels. Two different analytical methods were developed for cases with and without the in-situ horizontal stress acting along the beams. In the analytical model for the beams without horizontal stress a bilinear shape was assumed for the compression arch generated within the voussoir beams. The stability of the compression arch is governed by the energy method. The model requires an iterative procedure for convergence, and an algorithm was proposed for it. The analytical method was verified with numerical simulations by means of a discrete element code, UDEC. For the beams subjected to in-situ horizontal stress, the classic beam theory was employed to drive the analytical solution for it. The superposition method was used to obtain bending/deflection equations of the beam. The validity of both the assumptions and the developed method were, also, investigated by numerical simulations. The developed analytical method revealed that high Young’s modulus of a beam rock increases the stability of the beams against buckling but it causes higher stress within the compression arch which increases the probability of crushing failures in the beam abutments and midspan. In-situ horizontal stress along beams increases their stability against buckling and abutment sliding failure, but it raises the possibility of crushing failure at the abutments and the midspan.
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Stasiak, Marta. "Compression uniaxiale d'un matériau granulaire fragile très compressible - une étude par éléments discrets 3D." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI041/document.

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L’Agence nationale pour la gestion des déchets radioactifs (l’Andra) en France propose un nouveau type de voussoirs de tunnel pour les ouvrages très profonds. Pour éviter des segments de tunnel trop épais, ils proposent d’intégrer une couche de matériau granulaire sur l’extrados d’un voussoir moins épais. Cette approche prétend utiliser la grande compressilibité de la couche granulaire constituée de particules broyables et les transferts de charge interne au matériau granulaire pour réduire l’épaisseur du voussoir tout en gardant des performances mécaniques importantes. Un segment de tunnel avec une telle conception est appelé un VMC monobloc compressible (brevet en instance de l’Andra & CMC). Il s’agit d’un nouveau type de revêtement de tunnel particulièrement innovant.Cette thèse est consacrée à la création d’un modèle numérique capable de reproduire le comportement mécanique d’un couche granulaire très compressible à l’aide de la méthode aux éléments discrets (DEM) en 3D. Le milieu granulaire est constitué de particules d’argile cylindriques creuses appelées textitcoques. Chaque coque est un tube de 2 cm de long avec un diamètre de 2 cm. La faible épaisseur de la coque cylindrique la rend essentiellement constituée de vide entourée d’une fine couche d’argile. Dans le modèle, un cluster sécable (la coque) est généré à l’aide de clumps sphéro-polyédriques allon- gées . Ces clumps, appelés secteurs, sont associés entre eux en utilisant deux lois de contact adhésives. Si la combinaison des forces de contact normales et tangentielles satisfait un critère de charge spécifique, la coque se casse au niveau de l’interface entre les deux secteurs. L’outil DEM Rockable mis au point pour cette recherche peut fonctionner sur ces particules fragiles. Les propriétés mécaniques des coques, composé de 12 à 24 secteurs, sont ajustées à l’aide d’essais de compression radiale uniaxiale (verticale). Les expériences à l’échelle du grain sur les coques en argile cuite ont servi de référence. Nous avons déterminé la plage réelle de rupture et sa distribution statistique (Weibull). Les paramètres numériques et mécanique ainsi obtenus ont été validés avec succès dans le cas de la compression radiale d’une coque contrainte latéralement.Dans un premier temps, l’étude des assemblages de coques porte sur la caractérisation expérimen- tale des échantillons avec un controle sur les variables d’état initiales telles que la densité et l’orienta- tions des coques. La reconstruction 3D à partir de tomographies à rayons X d’échantillons de coques carottés dans l’extrados d’un voussoir nous a permis de caractériser l’anisotropie de l’orientation des particules. Il s’agit là d’une information précieuse pour la génération d’échantillons numériques ayant les caractéristiques initiales pertinentes. Deuxièmement, des simulations DEM de compressions oedo- métriques sur des échantillons de ⟨2 000⟩ coques sont réalisées. Une étude paramétrique permet de mettre en évidence le rôle des variables d’état initiales. Un ensemble bien choisi de variables initiales et des paramètres DEM correctement adaptés permettent d’obtenir des simulations prédictives pertinentes pour une comparaison avec les expériences de laboratoire. Une analyse micro-mécanique de l’effet de la proportion des grains cassés sur les contraintes locales exercées sur les coques (et les fragments) est effectuée. Il est observé que la rupture des coques entraîné une compressibilité élevée du matériau. Par conséquent, la réponse mécanique en déformation est considérée comme une conséquence directe de l’évolution de la rupture des particules. Pour finir, un modèle analytique de prédiction de la re- lation Contrainte↔Déformation est proposé dans le cas de la compression oedométrique. Ce modèle prédictif tient compte des variables internes du milieu granulaire comme la résistance mécanique en compression des coques
The National Agency for Radioactive Waste Management (FR Andra) in France suggested a new way to design a tunnel lining, especially, beneficial in the case of very deep tunnels. To avoid very thick tunnel segments, they propose to integrate a layer of granular material on the extrados of the thinner lining. This approach takes the advantages of the compressible capacity of the crushable particles and the load transfer in the granular material. A tunnel segment with such design is called a Mono-block Compressible Arch-segment VMC (Andra’s & CMC’s pending patent) and is an innovative new type of tunnel linings.This PhD dissertation is dedicated to the creation of a numerical model capable of reproducing the mechanical behaviour of this compressible granular layer using 3D Discrete Element Method (DEM). The granular packing is made of the brittle hollow coarse-size cylindrical particles, called shells. Each shell is a 2 cm long tube with a diameter of 2 cm. Its small thickness makes the cylindrical shell mainly made of void surrounded by a thin layer of clay. In the model, a breakable cluster (shell) is generated using sphero-polyhedral elongated clumps. These clumps, called sectors, are glued together using two adhesive contact force laws. If the combination of the normal and tangential contact forces exceeds a suitable failure criterion, a de-clustering of the shell (breakage) occurs. The DEM tool Rockable devel- oped for this research can operate on such crushable particles. The mechanical properties of the shell model, composed of 12 to 24 sectors, are adjusted in the case of a uniaxial (vertical) radial compres- sion of shells. The preceding grain-scale experiments on the true shells made of baked clay serve as a reference. We determine the true range of the failure tensile load and its statistical Weibull distribu- tion. The user-specified parameters is then successfully validated in the case of radial compression of a horizontally constrained shell.Firstly, the macroscopic study of shell assemblies focuses on the experimental characterisation of the samples with a control of the initial state variables like a number density and a spatial arrangement of shells (shells orientations). 3D reconstruction from X-ray tomographies of the original coated shells samples extracted from the extrados of a tunnel segment help us to characterise the anisotropy of the shells orientation. This is a piece of valuable information to the generation the numerical samples of shells with relevant initial features. Secondly, a series of DEM oedometric tests on ⟨1 000 : 2 000⟩ shells is simulated. A parametric study successfully leads to the understanding of each internal state variable role. A well-chosen set of initial variables with properly adapted DEM parameters give the relevant predictive simulations for a final comparison with the experimental oedometer tests. Thanks to a discrete insight into the micromechanics, the evolutions of the breakage level, the orientation anisotropy and the local stresses exerted on the shells (and/or the fragments) are quantified during the compression. The breakage of the shells result in high compressibility of the material. Therefore, the mechanical response is seen as a consequence of the breakage evolution. Finally, an analytical model is suggested in order to predict the Stress↔Void ratio relationship knowing the initial state of the sample and the tensile strength of the constituents: the shells

Книги з теми "Voussoirs":

1

Series, Michigan Historical Reprint. A practical theory of voussoir arches. By Prof. William Cain, C.E. Scholarly Publishing Office, University of Michigan Library, 2005.

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Частини книг з теми "Voussoirs":

1

Godart, B., and R. Lafuente. "Etude Experimentale de l’Adhesion entre un Beton et une Resine Epoxydique Lors de l’Assemblage par Collage de Voussoirs Prefabriques dans les Ponts en Beton Precontraint." In Adhesion between polymers and concrete / Adhésion entre polymères et béton, 474–83. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4899-3454-3_47.

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2

"joggled voussoirs." In Sir Banister Fletcher Glossary. © the Royal Institute of British Architects (RIBA) and the University of London, 2018. http://dx.doi.org/10.5040/9781350122741.1001224.

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3

"voussoir." In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 1495. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_220998.

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"voussoir." In Sir Banister Fletcher Glossary. © the Royal Institute of British Architects (RIBA) and the University of London, 2018. http://dx.doi.org/10.5040/9781350122741.1002718.

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"voussoir." In The Fairchild Books Dictionary of Interior Design. Fairchild Books, 2021. http://dx.doi.org/10.5040/9781501365171.4188.

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6

Sofianos, A. I., A. P. Kapenis, and C. Rogakis. "Voussoir beam analysis of an underground marble quarry." In Mechanics of Jointed and Faulted Rock, 515–20. Routledge, 2018. http://dx.doi.org/10.1201/9780203747810-79.

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7

Parland, H., and A. Miettinen. "A contact mechanical approach to the theory of the elastic voussoir arch." In Arch Bridges, 147–54. CRC Press, 2020. http://dx.doi.org/10.1201/9781003078494-22.

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