Les travaux de recherche présentés dans ce manuscrit ont été menés dans le cadre d’une convention CIFRE avec le Groupe Dacquin. Le sous-sol rennais est composé, en majorité, de schistes datés du Briovérien. Ces terrains, qui peuvent être rencontrés sur une grande partie du massif armoricain, présentent des degrés d’altération et de fracturation extrêmement variables à l’échelle du bassin rennais. Cette variabilité est très difficile à prendre en compte dans le cadre de la réalisation de soutènement, tant au niveau de la conception qu’au niveau de l’exécution. Dans un premier temps, des modélisations basés sur la méthode des éléments finis (logiciel PLAXIS 2D ©) ont été entreprises afin d’évaluer l’influence de la prise en compte d’une anisotropie du terrain sur le comportement de la paroi, en termes de moments et de déplacements. Le modèle utilisé permettait de prendre en compte une anisotropie élastique combinée à un critère orienté de plasticité de type Mohr-Coulomb. Les résultats obtenus avec ce modèle, pour différentes orientations du critère de plasticité, ont été comparés à ceux obtenus avec un modèle élastique isotrope et critère de plasticité de type Mohr-Coulomb. La même étude a été menée avec un second logiciel éléments finis (CESAR-LCPC) afin de comparer les résultats obtenus. Dans les deux cas une influence importante de l’orientation du critère de plasticité a été observée pouvant conduire à des résultats plus défavorables, selon l’orientation, que ceux obtenus avec le modèle isotrope. Ces résultats ont confirmé la nécessité de mieux caractériser l’anisotropie dans des matériaux tels que les schistes Briovériens. La caractérisation du matériau a donc été menée dans un second temps sur des prélèvements répartis sur la ville de Rennes et ses alentours (lors de travaux d’excavations ou sur des talus). Elle a permis de balayer les caractéristiques des schistes de l’échelle microscopique jusqu’à l’échelle macroscopique. La caractérisation microscopique, basée sur des observations au microscope à balayage électronique, des essais de diffraction des rayons X et des observations de lames minces, a permis de mettre en évidence des variations dans la pétrographie des échantillons (schistosité, granulométrie, teneur en argiles) permettant de les différencier en deux types : grès et siltites. La caractérisation à l’échelle macroscopique a été divisée en trois axes : la caractérisation de la matrice rocheuse et de son anisotropie (essais de compression uniaxiale, mesures de vitesses de propagation d’ondes et essais au scléromètre), la caractérisation de discontinuités exprimées (cisaillement direct) et la caractérisation de la résistance à l’usure (essais de broyabilité et Micro-Deval modifiés). Les siltites se sont révélées être extrêmement sensibles à l’eau (forte diminution des caractéristiques mécaniques mesurées) tandis que les échantillons gréseux l’étaient dans une moindre mesure. L’ensemble des essais réalisés a permis d’établir des ordres de grandeurs de variations des propriétés mécaniques des schistes du Briovérien. Enfin la classification des schistes briovériens élaborés par des géotechniciens pour la seconde ligne de métro de Rennes a été complétée en vue de mieux définir les classes intermédiaires de résistance. / Research work presented in this phD thesis was financed by a CIFRE grant given to Groupe Dacquin. Ground from the city of Rennes is, for the majority of it, composed of schists from the Brioverian era. These schists which can be encountered in the entire Armorican massif, present a weathering and a fracturing degree highly variable. This variability is hardly considered for the construction of retaining structure whether during the design step or the execution step. First, modellings using the finite elements method (PLAXIS 2D ©) have been carried out in order to evaluate the influence of ground anisotropy on the retaining wall behaviour (horizontal displacements and bending moments). The model used combined elastic anisotropy with an oriented plasticity criterion (type Mohr-Coulomb). Results obtained with this model, for different orientations of the plasticity criterion, were compared with the ones from the elastic isotropic model (with a Mohr-Coulomb plastic criterion). The same study was carried out with another finite elements software (CESAR-LCPC) in order to compare the results between the two sofwares. In both cases, an important influence of the orientation of the plasticity criterion was noted and lead to higher efforts in the wall, for certain orientations, compared to the isotropic model. These results confirmed the need of a better characterization of the anisotropy in materials such as Brioverian schists. In a second time, the characterization of the material was carried out on samplings spread over the city of Rennes and its area (during excavation work or on natural banks). Characterization was conducted from the microscopic to the macroscopic scale. Microscopic characterization based on observations with a scanning electron microscope, XRD analyses and thin section observations showed variations in the petrography of the samples (schistosity, granulometry, clay content) that lead to the differentiation of two types: sandstone and siltstone. The characterization at the macroscopic scale was divided into three parts: characterization of the rock matrix and its anisotropy (uniaxial compression tests, ultrasonic wave velocities and Schmidt hammer test), characterization of opened discontinuities (direct shear test) and the characterization of wear resistance (grindability and Micro-Deval tests). Siltstone samples were extremely sensitive to the water content (important decrease of the mechanical characteristics measured) whereas sandstones were less sensitive. The tests carried out lead to the definition of ranges for the mechanical properties of the Brioverian schists. Classification of Brioverian schists established by geotechnical engineers for the second subway line of Rennes was completed in order to better define the transitional states of strength of the material.

The subject of this thesis is the reconstruction of the road III/29920 in the village Kuks and Stanovice, from the junction with the road I/37 to the bridge e.č. 29920-1, 1.5 km in length.

Dans le cadre du projet du Grand Paris Express, de nouvelles lignes de métro vont voir le jour afin d'accompagner la croissance du trafic et améliorer la performance du réseau de transport en Ile-de-France. Plusieurs gares de la nouvelle ligne 15 sud vont être excavées à des profondeurs importantes pouvant atteindre les 40m et soutenues par des parois moulées butonnées. Le recours à une modélisation aux éléments finis s'avère indispensable au vu du contexte exceptionnel du projet à savoir la maitrise de l'impact sur les avoisinants, la présence de formations peu perméables, surconsolidées et déformables (Argile Plastique) et la nécessité d'utiliser des modèles de sols avancés pour décrire le comportement du sol dans des plages de déformations caractéristiques des soutènements rigides.Ce travail de recherche vise à approfondir la compréhension du comportement des écrans de soutènement d’excavations profondes en analysant les limites des méthodes de modélisations à savoir la méthode des coefficients de réaction et la méthode des éléments finis et en confrontant leurs résultats avec des mesures fiables issues d’une excavation réelle. Une instrumentation avancée composée de fibre optique et de cellules de pressions a été mise en place dans la gare de Fort d’Issy-Vanves-Clamart et le retour d’expérience de cette dernière permet de statuer sur la pertinence des modélisations réalisées. / As part of the Grand Paris Express project, new subway lines will be created in order to support traffic growth and improve the performance of the transport network in the Ile-de-France region (France). Several stations of the new line 15 will be excavated at great depths up to 40m and supported by strutted retaining walls. The use of a finite element modeling is essential regarding the exceptional context of the project especially the impact on the surrounding structures, the presence of impervious soils, overconsolidated and deformable (Plastic Clay) and the need to use advanced constitutive models to describe the soils behavior in the typical strain ranges proper to rigid retaining walls.This research aims to deepen understanding of the behavior of retaining walls for deep excavations by analyzing the limitations of modelling namely finite element method and subgrade reaction method and by comparing their results with a real monitored excavation. An advanced monitoring based on fiber optic and pressure cells was set up in the station of Fort d’Issy-Vanves-Clamart and the measurements feedback allow assessing the relevance of the different adopted modellings.

The heavy rainfall event in August 2002 in Saxony/Germany caused the break of a flood retaining basin in a valley of the Erzgebirge Mountains. The rainfall event with ists hyrologic characteristics and dam break event were analysed and an outflow hydrograph was determing. The propagation of the dam break flood wave in the valleyas of the Briesnitz and Müglitz Rivers has been simulated. Calculated values were compared with some observed data.

Während die güteorientierte Bewirtschaftung von Stauräumen in der Vergangenheit hauptsächlich bei der langfristigen Bewirtschaftung eine Rolle spielte, gewinnt sie in jüngerer Zeit immer mehr auch bei der kurzfristigen Abflusssteuerung als Vorentlastung und während der Hochwasserereignisse an Bedeutung. Dabei soll vor allem die Entlastung aus Horizonten mit geringerer Wasserqualität ermöglicht werden. Der vorliegende Beitrag beschäftigt sich mit den diesbezüglichen Möglichkeiten bei Nutzung vorhandener Entnahmeeinrichtungen und den Anforderungen an bauliche Ergänzungen. Es werden Grundsätze für die Planung, die Berechnung, den Betrieb und die Überwachung aus hydraulischer Sicht besprochen.

I detta examensarbete undersöks hur stödmurar av olika slag kan utföras på ett underhållsvänligare sätt. Med det menas att kostnaden för drift och underhåll ska hållas på en rimlig nivå med "normalt underhåll". Arbetet har genomförts på uppdrag av Nacka Kommun. Stödmurar har till uppgift att ta hand om jordtryck och även eventuella trafiklaster från vägar eller parkeringar. Detta ställer krav på att stödmuren är dimensionerad för de laster, och även för de olika typer av angrepp som kan förekomma med hänsyn till miljö. Stödmurar som är i stort behov av underhåll är idag ett problem för Nacka kommun som beställare. I dagens läge får kommunen sina stödmurar levererade av i princip samma typ och företag, vilket gör att kostnaderna för drift och underhåll också ligger på samma nivå. För att undersöka vilka typer av stödmurar som finns på marknaden, har en kategorisering gjorts av de vanligast förekommande stödmurarna, deras fördelar och nackdelar, samt användningsområden för de olika typerna. En LCC beräkning har gjorts för att lättare kunna se skillnaden mellan de olika stödmurarna med avseende på initialkostnader för produkten samt drift och underhållskostnader under dess livslängd. Betong som är det klart dominerande materialet som stödmurarna byggs av idag, har förklarats lite mer ingående med hänsyn till vilka skador som kan förekomma och även hur dessa kan undvikas. Ett av resultaten som är framtaget genom livscykelkostnadsberäkning visar, att gabioner som stödkonstruktion har minsta totalkostnad under dess livslängd. En av slutsatsen som arbetet har mynnat i är att med ett högre krav under projekteringsskedet kan skador som är ofta förekommande undvikas, eller hållas på en acceptabel nivå under stödmurens livslängd. Skadorna kan vara sprickbildning, avspjälkning eller korrosion av armering. / In this thesis an literature study have been done to examines how the retaining walls of various kinds can be performed in a maintenance friendly way. This means that the cost of operation and maintenance must be kept at a reasonable level with "normal maintenance". The work has been carried out on behalf of and supervised by Nacka Municipality. Retaining walls have the task of caring for earth pressure and also possible traffic loads from roads or parking areas. This demands that the retaining wall is dimensioned for the loads, and also for the different types of attacks that can occur with regard to the environment. Retaining walls that are in great need of maintenance is now a problem for Nacka municipality. At present, the municipality is getting all its retaining walls supplied by basically the same type and company. This means that the costs of operation and maintenance are also located on the same level. To examine the types of support walls that are available in the market today a categorization have been made of the most common retaining walls, their advantages, disadvantages and uses of the different types. An LCC calculation has been done to help identify the difference between the different support walls with respect to the initial cost of the product, and operation and maintenance costs over its lifetime. Concrete which is the dominant material that retaining walls are built of today have been explained more thoroughly with regard to the damage that may occur and also how they can be avoided. One of the results of the work is that with higher requirements during the design stage can damages that are frequently be avoided, or kept at an acceptable level during retaining walls durability. Effects may be cracking, spalling and corrosion of reinforcement.

A large component of the State of Utah's transportation network involves the use of MSE walls, which have proven useful in infrastructure for their reduced costs and footprint compared to other alternatives. As effective as MSE walls have been in responding to demands in transportation, they also have inherent challenges. For the majority of MSE walls the structure is limited in observation as structural components are buried as part of the soils mass. This inability to observe at can lead to the development of complex failure mechanisms, which can be difficult to assess and anticipate. As society becomes increasingly reliant on the transportation networks for goods, services, and security, properly understanding the potential failure mechanisms of MSE walls also increases in importance. This thesis discusses the development of an inspection procedure, data collection, geotechnical asset management database, and an evaluation of gathered information to be used in a reliability analysis of MSE walls for the State of Utah. The findings suggest areas of improvement in the design, specifications, maintenance, and further investigation of MSE walls.

Computer science is a discipline that is increasing in importance and value in our society, yet we are still failing to graduate a sufficient number of students to keep up with the demand required in the United States economy. We research several ways to retain students. We also discuss ways to increase students’ interest in the major, i.e., those who normally would not know about computer science. We discuss ways to increase female participation as well as overall participation in the major.

Current design codes of Mechanically Stabilized Earth (MSE) Walls allow the use lower lateral earth pressure coefficient (K value) for designing geosynthetics walls than those used to design steel walls. The reason of this is because geosynthetics walls are less rigid permitting the wall to deform enough to work under active pressures instead of at rest pressures as in steel walls. A new concept of crimped steel bars was recently introduced. This new type of bar was tested for tension and pullout behavior. Results on tests made on crimped bars show that putting those crimps in the steel bar will give us a better pullout behavior and a more flexible tensile behavior. This new type of steel bar will behave more like geosynthetics, allowing the wall to deform sufficiently to reach the necessary deflection to reach the active condition. The use of steel by current design codes is pushing MSE walls to be designed with more steel than needed. Measurements of the force in different walls showed that the steel is not being used even close to the maximum stress allowed by the code which is 50%. The proposed design methodology using crimped bars will help us save around 52% of steel volume compared to the actual design procedures. This means a huge improvement in the usage of steel versus actual designs. This improvement is obtained because of the efficient behavior of rounded bars under corrosion and because of the flexibility in the bars obtained with the crimps that will allow us to reach the active condition.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Kamran Zarrabi-Kashani. / M.S.