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.

Thesis solves an issue of application unconventional materials used in horizontal boring machine design. Chosen problem is solved step by step from general selection of suitable material for supporting structure. The selected material is applicated on WFT 13 CNC machine design from production of Fermat and it is created 9 conceptual options of machine’s frame. Finite element method is used for analysis of conceptual options. Based on data from analyses, the best option is selected for constructional part with use of multi-criteria PATTERN method. Constructional part of thesis elaborates on the design of selected conceptual option and gives recommendation for essential processes used in development and production of sandwich structures. The master’s thesis comes with new construction solution for supporting structure of selected machine and especially insight in development and production of new unconventional materials in horizontal boring machines design.

The diploma’s thesis deals with the current state of requirements for products resulting from directives of the European Parliament and the European Council. The aim of the thesis is a system analysis of the issue, proposal and justification of the chosen procedure for solving the objectives. Furthermore, the analysis of requirements of current standards and safety analysis related to the work of machine operators in the areas of operation, service and maintenance of horizontal boring machine WHN 13 CNC. The analysis is followed by a proposal for preventive measures for hazards where the value of risks and criticality is unacceptable, leading to their reduction.

The subject of this diploma thesis is design of motion axes of horizontal milling and boring machines. The first part contains literary research of linear systems of feeding and equipment. The second part contains calculations and the design of the motion machine axis. The 3D model of the motion axis designed in SolidWorks 2010 software and part of drawings are also included in this thesis.

This master's thesis deals with proposals for solutions to increase the stiffness of the slide for CNC horizontal boring standing in order to optimize the design of the slide. Selected problem was solved by sensitivity analysis using desegin of experiment in conditions of linear regression analysis. Data for the sensitivity analysis were obtained by using computational modeling using finite element method. The solution provides a view of the degree of influence on the deformation of the examined elements of the slide. Based on these results were selected elements with the greatest influence and created three ideological designs for improvement. Of these designs, was chose an optimal variant by PATTERN method acoording on the technical, economic and technical-economic aspect. This work offers a new look for the innovating the design to increase rigidity.

This thesis deals with conceptual design of spindle speeder head for headstock of horizontal boring machine of FERMAT Company. The thesis includes research part, which is initially given to horizontal boring machines and their accessories and continues with an overview and comparison of spindle speeders that are currently on the market. The work includes technical report, which is aimed on design of the belt drive including the idler pulley. Design of belt drive is based on the output of the calculation program developed by manufacturer of synchronous belts. Calculation part, mainly focused on the spindle and its bearings, is preceded by a part in which are calculated cutting forces for two technological operations. Calculation of the spindle part contains strength calculation of the spindle and equivalent basic rating life of spindle bearings, including calculating of radial stiffness at the spindle nose and calculation of optimal distance between the spindle bearings. At the end of the technical report is a financial summary, description of used components and the chosen design solution. The drawings which are based on model assembly processed in 3D CAD system, contains a drawing of the entire device and drawings of selected components.

This thesis deals with the diagnosis of a residential building from the late nineteen twenties for the needs of reconstruction. The methods generally used in the diagnosis of structures are briefly described in the theoretical part. More deeply this section describes the methods that were used during this particular research. The practical part deals with the diagnosis of the object itself. The first section describes the layout of the villa, its design solution, its faults and defects detected during the inspection. The next section deals with evaluating the current state of construction materials. Static reports of several structural parts were calculated in the last section.

Text in Afrikaans / Die doel van die studie is om die verband tussen werksontevredenheid (as gevolg van vervelige- en roetinewerk asook swak bestuursbenaderings) en werksafwesigheid te bepaal. Werksafwesigheid beïnvloed organisasiedoeltreffendheid nadelig omdat daar 'n tekort aan korrektiewe beamptes is as gevolg van die oorbevolking van gevangenes in Pollsmoor-gevangenis. 'n Omvattende oorsig van gepubliseerde literatuur oor werksafwesigheid het die empiriese navorsing van hierdie studie voorafgegaan. Die volgende doelwitte is bereik in hierdie studie, naamlik: * Om die werksafwesigheidsverskynsel by wyse van 'n literatuuroorsig te beskryf. * Om Pollsmoor-gevangenis se werksafwesigheidsyfers en -statistiek aan te toon en die navorsingspopulasie in terme van werksafwesigheidsgroepe te kategoriseer. * Om response rakende die vlak van tevredenheid met die aard van die werk, bestuursbenaderings en ander derde veranderlikes in die werksomgewing, van 'n verteenwoordigende steekproef van die navorsingspopulasie in te win, te ontleed en te beskryf. * Om bevindings en aanbevelings te maak ten opsigte van werkstevredenheid met vervelige- en roetinewerk, swak bestuursbenaderings asook derde veranderlikes. Die bevindings van hierdie studie behoort voordelig aangewend te kan word deur die Korrektiewe Dienste en akademiese belangegroepe. Die bevindings van hierdie studie verskaf ook waardevolle inligting oor werksafwesigheid vir toekomstige navorsing. Summary The aim of the study is to determine the relationship between work absenteeism and work satisfaction with boring- and routine work, poor management styles and third variables. The following objectives have been reached in this study, namely: * To describe the work absenteeism phenomenon by means of a literature review. * To show Pollsmoor prison's work absenteeism figures and -statistics and to categorize the research population in terms of work absenteeism groups. * To collect, analyse and describe the responses' pertaining to the level of satisfaction with the nature of the work, management styles and third variables in the work environment, from a representative sample of the research population. * To make findings and recommendations with regards to work satisfaction with boring- and routine work, poor management styles and third variables. The findings of this study could be utilized by Correctional Services and academic interest groups. / Business Management / M.Tech.

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.

Text in Afrikaans / Die doel van die studie is om die verband tussen werksontevredenheid (as gevolg van vervelige- en roetinewerk asook swak bestuursbenaderings) en werksafwesigheid te bepaal. Werksafwesigheid beïnvloed organisasiedoeltreffendheid nadelig omdat daar 'n tekort aan korrektiewe beamptes is as gevolg van die oorbevolking van gevangenes in Pollsmoor-gevangenis. 'n Omvattende oorsig van gepubliseerde literatuur oor werksafwesigheid het die empiriese navorsing van hierdie studie voorafgegaan. Die volgende doelwitte is bereik in hierdie studie, naamlik: * Om die werksafwesigheidsverskynsel by wyse van 'n literatuuroorsig te beskryf. * Om Pollsmoor-gevangenis se werksafwesigheidsyfers en -statistiek aan te toon en die navorsingspopulasie in terme van werksafwesigheidsgroepe te kategoriseer. * Om response rakende die vlak van tevredenheid met die aard van die werk, bestuursbenaderings en ander derde veranderlikes in die werksomgewing, van 'n verteenwoordigende steekproef van die navorsingspopulasie in te win, te ontleed en te beskryf. * Om bevindings en aanbevelings te maak ten opsigte van werkstevredenheid met vervelige- en roetinewerk, swak bestuursbenaderings asook derde veranderlikes. Die bevindings van hierdie studie behoort voordelig aangewend te kan word deur die Korrektiewe Dienste en akademiese belangegroepe. Die bevindings van hierdie studie verskaf ook waardevolle inligting oor werksafwesigheid vir toekomstige navorsing. Summary The aim of the study is to determine the relationship between work absenteeism and work satisfaction with boring- and routine work, poor management styles and third variables. The following objectives have been reached in this study, namely: * To describe the work absenteeism phenomenon by means of a literature review. * To show Pollsmoor prison's work absenteeism figures and -statistics and to categorize the research population in terms of work absenteeism groups. * To collect, analyse and describe the responses' pertaining to the level of satisfaction with the nature of the work, management styles and third variables in the work environment, from a representative sample of the research population. * To make findings and recommendations with regards to work satisfaction with boring- and routine work, poor management styles and third variables. The findings of this study could be utilized by Correctional Services and academic interest groups. / Business Management / M.Tech.