Este trabalho apresenta um estudo a respeito do comportamento do solo durante a escavação de um túnel, com foco na metodologia de escavação mecanizada. São abordadas diretrizes para a modelagem numérica de túneis com o emprego de diferentes métodos de cálculo, distintos modelos constitutivos para representação do comportamento do solo e duas maneiras de se representar o revestimento da escavação. Alguns conceitos fundamentais relacionados a escavações de túneis de grande diâmetro em solo com o emprego de máquinas tuneladoras são descritos, como os tipos de máquinas existentes (com ênfase nas máquinas do tipo EPB - Earth Pressure Balance), princípios de funcionamento e modos de operação, além de uma comparação deste método com a metodologia sequêncial tradicional. É realizada uma revisão bibliográfica sobre distintos métodos de cálculo para estimar a estabilidade de uma escavação, a previsão da deformação no maciço e os esforços atuantes no revestimento do túnel. O trabalho também apresenta uma revisão de publicações recentes a respeito da modelagem numérica de túneis escavados mecanicamente, destacando algumas diferenças em relação à metodologia sequencial. Uma das diferenças é com relação à simulação do revestimento do túnel, com a possibilidade de se considerar as propriedades das juntas dos anéis. Outro ponto distinto é o método de cálculo empregado, levando em conta na simulação aspectos específicos da escavação mecanizada, como pressão de frente aplicada, vazio anelar e injeção de grout. É feita uma breve introdução e são apresentados os conceitos básicos de dois modelos constitutivos do solo: o modelo elastoplástico perfeito conhecido como Mohr-Coulomb e o modelo elastoplástico com endurecimento Hardening Soil. Utilizando alguns dos conceitos estudados na revisão bibliográfica, são realizadas análises numéricas bidimensionais retroanalisando um caso real de escavação com tuneladora. Foi utilizado o programa de elementos finitos Plaxis para realizar comparações entre os métodos de cálculo do alívio de tensões e da contração, além da simulação do revestimento com ou sem a consideração das juntas. Por fim é feita uma análise crítica dos resultados obtidos nas diferentes modelagens numéricas. / This research presents a study about the soil behavior during the excavation of a tunnel, focusing on the mechanized excavation methodology. Guidelines for the numerical modeling of tunnels with the use of different calculation methods, distinct constitutive models to characterize the soil behavior and two ways of representing the lining of the excavation are addressed. Relevant aspects regarding excavations of large diameter tunnels in soil with the use of TBM (Tunnel Boring Machine) are presented, like types of machines, with the focus on the Earth Pressure Balance (EPB) machines, fundamental concepts of the methodology and operation modes, besides a comparison of this method with the traditional sequential methodology. A literature review on different methods of calculation to estimate the excavation stability, the prediction of ground deformation and the efforts acting in the tunnel lining is made. The research also presents a review of recent publications regarding numerical modeling of mechanically excavated tunnels, highlighting some differences with the sequential method. One of these differences is related to the simulation of the tunnel lining, with the possibility of considering the properties of the ring joints. Another different point is the calculation method employed, considering in the simulation specific aspects of mechanized excavation, as front pressure applied, ring void and grout injection. A brief introduction is made about constitutive models to represent the soil behavior and the basic concepts of two constitutive soil models are presented: Mohr-Coulomb and Hardening Soil. Using some of the concepts studied in the literature review, it is performed two-dimensional numerical analysis with a back-analysis of a real case, using the finite element model program Plaxis, comparing the calculation methods of stress relieving and contraction, as well as the tunnel lining simulation with or without consideration of the joints. Finally, it is made a critical analysis of the results of the numerical simulations.

Este trabalho apresenta um estudo a respeito do comportamento do solo durante a escavação de um túnel, com foco na metodologia de escavação mecanizada. São abordadas diretrizes para a modelagem numérica de túneis com o emprego de diferentes métodos de cálculo, distintos modelos constitutivos para representação do comportamento do solo e duas maneiras de se representar o revestimento da escavação. Alguns conceitos fundamentais relacionados a escavações de túneis de grande diâmetro em solo com o emprego de máquinas tuneladoras são descritos, como os tipos de máquinas existentes (com ênfase nas máquinas do tipo EPB - Earth Pressure Balance), princípios de funcionamento e modos de operação, além de uma comparação deste método com a metodologia sequêncial tradicional. É realizada uma revisão bibliográfica sobre distintos métodos de cálculo para estimar a estabilidade de uma escavação, a previsão da deformação no maciço e os esforços atuantes no revestimento do túnel. O trabalho também apresenta uma revisão de publicações recentes a respeito da modelagem numérica de túneis escavados mecanicamente, destacando algumas diferenças em relação à metodologia sequencial. Uma das diferenças é com relação à simulação do revestimento do túnel, com a possibilidade de se considerar as propriedades das juntas dos anéis. Outro ponto distinto é o método de cálculo empregado, levando em conta na simulação aspectos específicos da escavação mecanizada, como pressão de frente aplicada, vazio anelar e injeção de grout. É feita uma breve introdução e são apresentados os conceitos básicos de dois modelos constitutivos do solo: o modelo elastoplástico perfeito conhecido como Mohr-Coulomb e o modelo elastoplástico com endurecimento Hardening Soil. Utilizando alguns dos conceitos estudados na revisão bibliográfica, são realizadas análises numéricas bidimensionais retroanalisando um caso real de escavação com tuneladora. Foi utilizado o programa de elementos finitos Plaxis para realizar comparações entre os métodos de cálculo do alívio de tensões e da contração, além da simulação do revestimento com ou sem a consideração das juntas. Por fim é feita uma análise crítica dos resultados obtidos nas diferentes modelagens numéricas. / This research presents a study about the soil behavior during the excavation of a tunnel, focusing on the mechanized excavation methodology. Guidelines for the numerical modeling of tunnels with the use of different calculation methods, distinct constitutive models to characterize the soil behavior and two ways of representing the lining of the excavation are addressed. Relevant aspects regarding excavations of large diameter tunnels in soil with the use of TBM (Tunnel Boring Machine) are presented, like types of machines, with the focus on the Earth Pressure Balance (EPB) machines, fundamental concepts of the methodology and operation modes, besides a comparison of this method with the traditional sequential methodology. A literature review on different methods of calculation to estimate the excavation stability, the prediction of ground deformation and the efforts acting in the tunnel lining is made. The research also presents a review of recent publications regarding numerical modeling of mechanically excavated tunnels, highlighting some differences with the sequential method. One of these differences is related to the simulation of the tunnel lining, with the possibility of considering the properties of the ring joints. Another different point is the calculation method employed, considering in the simulation specific aspects of mechanized excavation, as front pressure applied, ring void and grout injection. A brief introduction is made about constitutive models to represent the soil behavior and the basic concepts of two constitutive soil models are presented: Mohr-Coulomb and Hardening Soil. Using some of the concepts studied in the literature review, it is performed two-dimensional numerical analysis with a back-analysis of a real case, using the finite element model program Plaxis, comparing the calculation methods of stress relieving and contraction, as well as the tunnel lining simulation with or without consideration of the joints. Finally, it is made a critical analysis of the results of the numerical simulations.

With the advent of the large diameter tunnel boring machine (TBM), mechanically driven large diameter tunnel is becoming a more attractive option. During operation, a large diameter tube allows for stacked deck configuration with shafts dropped to platform level (no station caverns). The extensive information has been compiled on innovative TBM tunneling projects such as the Barcelona Line 9, where the concept of continuous station has been used for the first time, stormwater management and roadway tunnel in Malaysia, where the floodwater bypass tunnel and the road tunnel are incorporated in a single bore tunnel. The decision making process that led to the construction of large bore tunnel is also presented. A detailed study has been carried out to determine the necessary face support pressure in drained conditions (with ideal membrane), and undrained conditions. The effects of tunnel diameter, cover-to-diameter ratio, at-rest lateral earth pressure coefficient, and soil shear strength parameters on the local and global stability of the excavation face of mechanically-driven tunnels have been investigated. The relation between the face support pressure and the calculated tunnel face displacement gave the minimum face support pressure that should be applied on the tunnel face to avoid abrupt movement of the tunnel face. Simple expressions have been developed for the support pressure as a function of tunnel diameter, cover depth, lateral earth pressure coefficient, and soil strength parameters. The required face support pressures are compared to the analytical solutions available from the literature. It has been found that analytical stability solutions generally underestimate the required face support pressure and excessive deformation will take place in the ground near the tunnel heading when these solutions are used. By using plastic limit analysis, a rigid and deformable prism-and-wedge model has been developed; in undrained conditions, upper bound solutions against collapse load are derived for face pressure. Deformable blocks enabled to take into account the effect of non-uniform support pressure due to the unit weight of the supporting medium. The upper bound solution derived as a function of tunnel diameter and cover depth, normalized undrained shear strength ratio, and unit weight of the ground and the supporting medium was compared with a solution available from the literature. Largest face support pressure was obtained when the uniform face support pressure was applied and it was smallest when identical unit weight was used for the ground and the supporting medium. / text

A combined geological and rock mechanics approach to tunnel face behaviour prediction, based on improved understanding of brittle fracture processes during TBM excavation, was developed to complement empirical design and performance prediction for TBM tunnelling in hard rock geological conditions. A major challenge of this research was combining geological and engineering terminology, methods, and objectives to construct a unified Geomechanical Characterisation Scheme. The goal of this system is to describe the spalling sensitivity of hard, massive, highly stressed crystalline rock, often deformed by tectonic processes. Geological, lab strength testing and TBM machine data were used to quantify the impact of interrelated geological factors, such as mineralogy, grain size, fabric and the heterogeneity of all these factors at micro and macro scale, on spalling sensitivity and to combine these factors within a TBM advance framework. This was achieved by incorporating aspects of geology, tectonics, mineralogy, material strength theory, fracture process theory and induced stresses. Three main approaches were used to verify and calibrate the Geomechanical Characterisation Scheme: geological and TBM data collection from tunnels in massive, highly-stressed rock, interpretation of published mineral-specific investigations of rock yielding processes, and numerical modelling the rock yielding processes in simulated strength tests and the TBM cutting process. The TBM performance investigation was used to identify the mechanism behind the chipping processes and quantify adverse conditions for chipping, including tough rock conditions and stress induced face instability. The literature review was used to identify the critical geological parameters for rock yielding processes and obtain strength and stiffness values for mineral-specific constitutive models. A texture-generating algorithm was developed to create realistic rock analogues and to provide user control over geological characteristics such as mineralogy, grain size and fabric. This methodology was applied to investigate the TBM chipping process to calibrate the Geomechanical Characterisation Scheme. A Chipping Resistance Factor was developed to combine the quantified geological characteristic factors and laboratory strength values to predict conditions with high risk of poor chipping performance arising from tough rock. A Stress-Related Chip Potential Factor was developed to estimate conditions with high risk of advance rate reduction arising from stress-induced face instability. / Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2008-09-25 23:58:58.071

The Master Thesis work this report is based upon has been conducted in cooperation with Svea Teknik AB. Svea Teknik is a consultant firm which is developing parts of a tunnel boring machine on behalf of Atlas Copco. The machine is being developed to mechanically excavate hard rock by fixating itself in the tunnel and then press a large rotating cutter-wheel equipped with disc-cutters against the tunnel wall. The disc-cutters are the tools that are in direct contact with the hard rock and are therefore exposed to extensive wear and needs to be replaced on a regular basis.The purpose of this Master Thesis has been to develop a service equipment that will enable time effective and safe changes of disc-cutters. The disc-cutters have a diameter of 17 inches and weigh about 130 kg. The available space in the tunnel is very limited which puts strict requirements on the size of the service equipment.A specification of requirements was set up based on the background study made in the Master Thesis. Concepts to solve the problem were then generated and evaluated against each other.A concept consisting of a wagon with three slots for disc-cutter transport, a foldable crane with a hoist and a lifting tool adapted to the disc-cutters were chosen for further development. Since the concept was quite extensive the decision was made to focus the work around the lifting tool.By loading new disc-cutters onto the driven wagon together with the foldable crane and the lifting tool, the equipment can be transported past the machine in the tunnel and the crane can then be set up in front of the machine's cutter-wheel. The lifting tool is then lifted by the hoist to enable the disc-cutters in the cutter-wheel to be replaced.The lifting tool consists of two claws that close around the disc-cutter to fixate it geometrically and a counter weight to enable easy positioning of the disc-cutter by hand. The lifting tool is dimensioned according to two different load cases and was verified by FE-analysis.Recommendations for future work and more detailed design were set up. / Examensarbetet denna rapport baseras på, har utförts i samarbete med Svea Teknik AB. Svea Teknik är ett konsultföretag som på uppdrag av Atlas Copco utvecklar delar av en gruvmaskin för tunnelborrning. Maskinen konstrueras för att mekaniskt krossa berget genom att fixera sig i tunnelgången och pressa ett stort skärhjul utrustat med diskformade s.k. kuttrar mot bergväggen samtidigt som skärhjulet roterar. Då kuttrarna är de verktyg som står i direkt kontakt med berget slits de markant och måste bytas ut för service med jämna mellanrum.Detta examensarbete har syftat till att utveckla en serviceutrustning för att möjliggöra snabba och smidiga byten av dessa kuttrar som har en diameter på 17 tum och väger ca 130 kg. Då utrymmet i tunneln är väldigt begränsat finns stora krav på utrustningens storlek.En kravspecifikation, baserad på examensarbetets bakgrundsstudie, utarbetades för att ligga till grund för de genererade koncept som sedan utvärderades gentemot varandra.Efter att ett koncept bestående av en transportvagn med plats för tre kuttrar, en vikbar kran med telfer samt ett specialanpassat kloförsett lyftverktyg hade valts togs beslutet att fokusera arbetet kring lyftverktyget för att begränsa projektets omfång.Genom att lasta nyservade kuttrar på den drivna transportvagnen tillsammans med den hopvikta kranen och lyftverktyget kan den ledas fram förbi maskinen i tunneln och kranen monteras upp framför maskinens skärhjul. Lyftverktyget hängs sedan upp i kranen för att möjliggöra att kuttrar lossas respektive monteras.Lyftverktyget består av två klor som sluts runt kuttern för att fixera den formbetingat samt en motvikt för att för hand kunna ändra rotationen av verktyget kring infästningspunkten. Lyftverktyget dimensionerades utifrån två uppsatta lastfall och verifierades sedan med FEM-analyser

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24896号 / 工博第5176号 / 新制||工||1988(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)准教授 PIPATPONGSA Thirapong, 教授 肥後 陽介, 教授 岸田 潔, 教授 安原 英明 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

La fréquence des opérations de maintenance lors de l’excavation du sol par les tunneliers est problématique pour les entreprises de travaux publics. Ces opérations de maintenance engendrent des temps morts onéreux et nécessitent l'intervention d'opérateurs dans des conditions de travail hyperbares. Une des raisons aux nombreuses interventions humaines pour la maintenance est l’endommagement des outils racleurs du sol excavé (dents) qui sont placés sur la tête du tunnelier. Ces outils sont sujets à l’usure compte tenu de l’abrasivité des différents milieux qu’ils rencontrent. Le but de cette thèse est de contribuer à augmenter d’au moins 20% la durée de vie des matériaux constitutifs de ces outils, afin de réduire les différentes opérations de maintenance qui exposent les opérateurs à des risques importants. Pour atteindre cet objectif, les investigations menées dans ce travail ont porté sur plusieurs axes. Dans un premier temps, une expertise est menée pour identifier les modes d’endommagement prédominants sur les inserts à base de carbure de tungstène placés sur les dents ; ensuite, de nouveaux matériaux avec des propriétés mécaniques et des microstructures optimisées, développés dans le cadre du projet européen NeTTUN, sont caractérisés sur des bancs d’essais représentatifs. Ces essais ont permis de bien comprendre les mécanismes d’usure des nouveaux matériaux à base de carbure de tungstène. Les résultats de ce travail peuvent ensuite donner lieu à de nouvelles orientations en matière de choix de matériaux pour renforcer les dents de tunnelier. / The frequency of maintenance operations during the excavation of the ground by the tunnel boring machines (TBM) is problematic for civil engineering companies. These maintenance operations provoke expensive timeouts and they bring in excavation operators in risky hyperbaric work conditions. One of the reasons which leads to the numerous human interventions for the maintenance is the damage of drag bits located on the cutting wheel of the TBM. These drag bits undergo wear due to the abrasiveness of the various media they meet. The purpose of this thesis is to contribute to increase by 20 % at least the lifetime of the materials of the dag bits, in order to reduce the various maintenance operations which expose the operators to important risks. To achieve this goal, the investigations led in this work concerned several axes. At first, an expertise is led to identify the wear modes prevailing on the carbide inserts located on the drag bits; then, new materials with enhanced mechanical properties and optimized microstructures, developed in the framework of the European project NeTTUN, are characterized on representative lab testing devices. These tests allowed us to understand well the wear mechanisms of the newly developed grades of tungsten carbides. The results of this work can lead to new strategies for the selection of materials to reinforce the drag bits.

Le travail de thèse présenté dans ce mémoire vise à analyser et à comprendre les mécanismes mis en jeu au niveau de l’impact du creusement d’un tunnel par bouclier à front pressurisé sur des fondations profondes avoisinantes. Cette thèse a été réalisée dans le cadre du projet européen NeTTUN, au sein du Laboratoire de Tribologie et de Dynamique des Systèmes (LTDS) de l’ENTPE. L’approche phénoménologique conduite lors de ces travaux repose sur deux importantes campagnes expérimentales réalisées à l’aide d’un dispositif unique au plan international de modèle réduit 1g de tunnelier à pression de terre (échelle de l’ordre de 1/10eme). La forte originalité de ce dispositif est de pouvoir simuler de façon réaliste les principales étapes du processus tridimensionnel d’excavation mécanisé d’un tunnel. Dans le cadre de cette thèse, le dispositif existant de modèle réduit de tunnelier a dans un premier temps été reconfiguré afin de pouvoir répondre aux besoins du programme expérimental envisagé. Des modèles physiques de fondations profondes (pieux et groupes de pieux) et de barrières de protection ont été conçus dans le cadre des lois de similitude, fabriqués et instrumentés. Deux campagnes expérimentales d’envergure ont été réalisées en massif de sable sec : l’une concerne les effets du passage d’un tunnelier à front pressurisé sur des fondations profondes avoisinantes (pieux, groupe de pieux), l’autre traite de l’efficacité de barrières de protection (parois moulées) utilisées pour limiter ces effets. Différents paramètres qui influencent l’interaction tunnelier - sol - fondations ont été considérés comme la distance relative tunnel / fondation, la pression frontale de soutènement appliquée par le TBM sur le terrain ou encore la hauteur des barrières de protection. L’analyse phénoménologique menée à l’échelle du modèle concerne en particulier l’évolution des champs de contraintes et de déplacements dans le terrain autour du tunnelier, les déplacements relatifs sol - pieu et sol- barrière, la redistribution des efforts au sein des fondations. L’importante base de données et d’analyse ainsi constituée a été mise à profit pour la validation d’outils de modélisation numérique développés par l’Université de Rome au sein du projet NeTTUN. / The major goal presented in this thesis was to analyze and investigate the mechanisms, which are involved in the impact of the tunnels excavated thanks to an Earth Pressure Balanced Shield on nearby deep foundations. This thesis was realized in European project NeTTUN and the work had been done in the Laboratory of Tribology and Systems Dynamics (LTDS) of ENTPE. During these works, phenomenological approach was based on two important experimental campaigns carried out using a unique device at the international level of a 1g scale model of earth-pressure tunnel boring machine (scale of the order of 1 / 10). The state of the art of this device was to be able to simulate in possibly realistic way the main stages of the three-dimensional process of mechanized excavation of a tunnel. In the framework of this thesis, the existing model tunneling machine device was initially reconfigured in order to reach the expectations of the experimental program envisaged. Physical models of deep foundations (piles and groups of piles) and protective barriers were designed under the similitude laws, manufactured and instrumented. The two large-scale experimental campaigns have been carried out in a dry sand massif. The first one concerned the effects of the passage of a pressurized tunnel boring machine on nearby deep foundations (piles, group of piles), whereas another one dealed with the effectiveness of mitigation procedure (diaphragm walls) used to limit these effects. Different parameters that influenced on the tunneling: soil - foundation interaction considered as the relative tunnel / foundation distance, the frontal face pressure applied by the TBM in the field or the height of the protective barriers. The phenomenological analysis carried out at the scale of the model concerned in particular the evolution of the fields of stresses and displacements in the ground around the tunnel boring machine, relatives pile / soil and wall / soil displacements and the redistribution of stresses along the pile foundations. The large database and analysis constituted was used for the validation of numerical modeling tools developed by the University of Rome within the NeTTUN project.