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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Konventionell sprängning eller fullortsborrning som tunneldrivningsmetod? / Drill and blast or TBM as tunneling method?

Bergström, Ida Gomez, Bahr, Maximilian von January 2015 (has links)
I denna rapport har de två vanligaste tunneldrivningsmetoderna konventionell sprängning och fullortsborrning, TBM undersökts. Konventionell sprängning innebär att små borrhål görs i berget där sprängmedel förs in för att sedan spränga bort materialet. Fullortsborrning innebär å andra sidan att en enda stor borr används vilket gör att tunnelhålet får samma dimension som själva borren. Målen med detta arbete var att ta reda på vilka faktorer som påverkar valet mellan dessa två metoder i Stockholm, att göra en jämförelse mellan metoderna ur ekologisk- och ekonomisk hållbarhetssynpunkt samt att undersöka hur hanteringen och användningen av det uttagna bergmaterialet för respektive metod ser ut. Med hjälp av kvalitativa intervjuer med tio personer inom tunnelbyggnadsbranschen har dessa mål besvarats. De resultat som framkommit visar att det finns ett flertal faktorer som påverkar valet, några mer än andra. De tyngst vägande är de ekonomiska och erfarenhetsmässiga faktorerna som talar till fördel för konventionell sprängning. Fullortsborrning har dock funnits vara den fördelaktiga metoden ur ett hållbarhetsperspektiv, främst eftersom den ger en mindre påverkan på den omgivande miljön. Hanteringen och användningen av det uttagna bergmaterialet har däremot visat att konventionell sprängning kan vara fördelaktigt eftersom det idag finns en etablerad industri kring just sprängt bergmaterial. Fullortsborrat material är idag inte efterfrågat på grund av dess dåliga kvalitet. / In this report, the two most common tunnelling methods are investigated. These are conventional drill and blast and full-face boring, TBM. The drill and blast method is when a small drill is used to make bore holes where the explosives are inserted to blast away the material. Full-face boring is when a single large bore drills a tunnel with the same dimension as the bore head. The objectives of this report were to find out what factors influence the choice between these two methods in Stockholm, to make a comparison between the methods from ecological and economic sustainability point of view and to explore the handling and use of the extracted rock material for each method. By conducting qualitative interviews with ten experts on different aspects of tunnel construction, these objectives have been answered. The results obtained show that there are several factors that influence the choice, some more than others. The predominant aspect is the economic and experiential factors that speak in favour of conventional blasting. Full-face boring, however, has been found to be the advantageous method from an ecological perspective of sustainability, mainly because it has a lower impact on the surrounding environment. Handling and use of the extracted rock material has however proven that conventional drill and blast is the favourable method since there is an established industry around blasted material in Stockholm today. Full-faced drilled material is not in demand today because of its poor quality.
42

Laser scanning of overbreak anddeformation for crosscuts at Malmbergetmine

Alkayal, Adam January 2020 (has links)
Nowadays, new measurement technologies are being used in underground mining operationsto increase the safety factors and solve several mining challenges to save time and improve theeffectiveness of mining operations. One of the new tools is the uGPS Rapid Mapper, which hasrecently entered the market. LKAB is one of the companies looking to use modern technologyto help solve problems in its Kiirunavaara and Malmberget underground mines. The operatingmechanism of the uGPS Rapid Mapper was studied and some investigations were carried outwith the device.The first part of this thesis studied the repeatability and accuracy of the uGPS Rapid Mapper™System during actual use. A number of tests were completed and data analysis viaCloudCompare software was carried out. The result of these tests showed that the uGPS RapidMapper is an efficient device that can be counted on for future work with higher reliability interms of output results.The second part of this thesis determined the overbreak percentage caused by blasting and otherfactors. The uGPS Rapid Mapper was used to scan different parts of the mine (areas that havebeen developed more than three months ago and newly-developed areas). The percentageoverbreak that occurred in these selected areas in the mine and the cause of the overbreak wereanalysed. The study indicated that the data collected by uGPS and analyzed using theDeswik.CAD (Reconciliation Tool) is a very effective method for calculating the overbreak.Most of the study areas in this study however showed an overbreak percentage of more than16% with a varying form of percentage overbreak. The potential causes of this variation are asa result of geological structures or more pronounced mining activities, or operations such asdrilling and blasting, scaling, charging and explosives parameters. The results also clearlyindicated that underground deformation, rock support installation, especially the application ofshotcrete plays a major role in filling the void after rock falls and reducing geometric crosscutentry size.The final part of the work investigated the deformation that occurred in some parts of the minewhere it is believed to have deformations exceeding 20 cm. These parts of the mine werescanned regularly for four months, and the data were analysed using CloudCompare andDeswik.CAD software. The result of the deformation studies showed that the uGPS RapidiiMapper can effectively recognize the changes underground where the recorded deformationhas exceeded 40 cm.The results confirmed that the uGPS Rapid Mapper can be used to effectively monitorunderground changes in the mine through regular underground scanning and analysis of thescanned data.
43

Near Surface High Resolution Seismic Imaging of Glacial Deposits in Sweden at the Heby and Marsta Sites

Sun, Ruixue January 2020 (has links)
Near surface seismic methods have the potential for mapping theoverburden and bedrock in the Nordic environment. They can provideeffective information about shallow glacial deposits and groundwaterresources in Sweden. We analysed seismic data from the Heby andMarsta sites with the aim of improving the imaging resolution andunderstanding the substructures better, developing systematicstrategies to deal with the detection of aquifers and the delineation ofsome significant boundaries. The general scheme for every case studyis composed of processing, inversion and forward modelling.Processing strategies for the Heby and Marsta have different keypoints, because of the different acquisition equipment and systems.The Heby data were acquired by dynamite and collected withconventional geophones, while the Marsta data were acquired by asledge hammer source and a 3C data landstreamer with MEMSsensors. Inversion can be used for enhancing image quality,particularly in velocity model building. Strongly undulatedsubstructures in the Heby profile cause ambiguities and conflictingdips in the stacked section. By employing the tomographic inversionresult as a starting point to implement prestack depth migration(PSDM) the final image shows better continuity at the top of bedrockand shallow layers are resolved clearer. At Marsta, vertical and radialcomponent data were used to obtain PP and PS information,respectively, to delineate the bedrock surface. Common conversionPoint (CCP) binning of the radial component identifies the surface inbetter resolution, even a 2m variation in the depth of the bedrock canbe seen. PSDM radial component data supports and complements theresult from the CCP binning. In both the Heby and Marsta cases,forward modelling was applied for testing processing workflows forthe field data using models that mimick the real substructures.Acoustic modelling was used for understanding the P-wave responsein the Heby single component data, while elastic wave modelling wasperformed to simulate the multicomponent data at Marsta. The resultsdemonstrate that a comprehensive application of seismic methods inthe near surface (shallower than 100m) can provide adequateresolution. Noteworthy is that an accurate velocity estimation plays asignificant role in the whole scheme for seismic imaging. Thestrategies for building the velocity are also meaningful in thisresearch.
44

Three-dimensional effects in slope stability for shallow excavations : Analyses with the finite element program PLAXIS

Lindberg, Niclas January 2020 (has links)
The purpose with this study was to investigate the impact of three-dimensional effects in slope stability for three-dimensional excavations and slopes with cohesive soils and compare the results with the method provided by the Swedish commission of slope stability in 1995 regarding three-dimensional effects. Both the factor of safety and the shape of the slip surface was compared between the methods but also the results from their equivalent two-dimensional geometry. The investigation was performed with models created in the finite element software PLAXIS 3D and the limit equilibrium software GeoStudio SLOPE/W. Three-dimensional excavations with varying slope angles, external loads and slope lengths were tested for three different geometry groups in PLAXIS 3D. The equivalent two-dimensional geometries were modeled with SLOPE/W and recalculated with the three-dimensional effect method provided by the Swedish commission of slope stability. The results show that the methods match well for slopes with inclinations 1:2 and 1:1 when an external load is present on the slope edge, and the factor of safety is greater and not close to 1,0. For an excavation with vertical walls or when no external load is present, the methods match poorly. The results also show that for a long and unloaded slope, the factor of safety approaches the value obtained from a simplified two-dimensional analysis. The results imply that the recommendations from the Swedish commission of slope stabilityare reliable for simple calculations of standard cohesive slopes. Keywords: Slope stability; 3D-effects; FEM
45

The behaviour of mica-rich aggregates under the temperate climate conditions

Novikov, Evgeny January 2008 (has links)
In regions of temperate climate the destructive influence of frost action such as frost heave in winter and thaw weakening in spring are the main contributors to severe deterioration of the pavement structure. A number of studies on construction aggregates and field observations of road failures, especially caused by seasonal fluctuations of temperature, have revealed a negative influence of unbound mica-rich rock aggregates on the service life of road construction. The aim of this thesis was to investigate the behaviour of mica-rich aggregates under the temperate climate conditions. The study focuses on measurements of volume change (frost heave), capillarity rise and interaction between water and mica-rich aggregates. The materials studied in this research are commercially available unbound road construction aggregates with varying free mica grains, and originating from different regions of Sweden. The mineral composition of the samples has been determined by polarizing microscopy using a point-count method. In Paper I, the materials were exposed to freeze-thaw cycling in order to register the volume change (in terms of frost heave). The results show that mica-rich base-course aggregates have a large potential to produce frost heave. The results from the test for determining capillary rise (Paper II) indicate a direct correlation between mica content of the aggregates and capillary rise values confirming the capability of mica-rich unbound aggregates to transport and absorb higher amounts of water. The interaction of mica-rich aggregates with water in terms fraction sizes and free mica content was studied in Paper III, measuring water storage capacity and specific water saturation values. The results reveal a strong positive correlation between mica content, grain size, water sorption and water storage capacity of the aggregates. The overall results of this research bring the mineralogy of the fines into focus when evaluating frost susceptibility of unbound aggregates and can be considered when estimating threshold values of free mica grains in crushed road materials. / <p>Godkänd; 2008; 20080611 (ysko)</p>
46

Sannolikhetsbaseraddimensionering av geotekniskbärförmåga för pålar i grupp : En jämförelse mellan gällande normer och ensannolikhetsbaserad metod

Andersson, Jimmie January 2014 (has links)
No description available.
47

Prognostisering av sättning frånhög uppfyllnad i Högbytorp : Numerisk‐analytisk jäföelse samt uppmäta sätningar

Suta, Ferencz January 2014 (has links)
No description available.
48

Effect of heterogeneous densification due to vibroflotation on liquefaction resistance

Vranckx, Alexander January 2017 (has links)
No description available.
49

Two-dimensional analysis of the failure mechanisms of an embankment supported by rows of dry deep mixing columns.

Peeters, Bieke January 2017 (has links)
No description available.
50

Kapacitetsuppföljning av genomförd spontdrivning

Nilsson, Tobias, Johansson, Sofie January 2018 (has links)
Tätspont är en vanligt förekommande typ av stödkonstruktion och är i dagslägen den mest tids- och kostnadseffektiva på marknaden. Tätsponter består utav sammanfogade spontplankor i stål som ofta drivs med vibrationsutrustning. Ett antal studier har sedan början av 2000-talet undersökt vilka faktorer som påverkar drivbarheten av en planka. Men kunskapen kring förväntat produktionskapacitet, sett till ett helt projekt, är fortfarande bristfällig och det enda indikationerna för svår drivning som används idag är förekomsten av block och fast friktionsjord. Detta medför osäkerheter vid projektering som kan leda till förseningar och ökade kostnader. Målet med detta arbete är att möjliggöra för uppskattande av kapacitet vid spontdrivning i ett tidigt skede av projekt. Arbetet avser att besvara vilken kapacitet som kan förväntas vid spontdrivning och om det går att förutse denna utifrån de parametrar som kan utvärderas från en jord-bergsondering. För att uppfylla arbetets mål har nio spontprojekt utförda av Skanska Sverige AB studerats. Utifrån information från dagböcker och spontprotokoll, från dessa projekt, har kapaciteten för spontdrivning sammanställts. Sammanställd data för kapaciteten har sedan kopplats till utvärderat borrmotstånd från jord-bergsonderingar för att undersöka eventuellt samband. Det mest väsentliga resultatet av genomförd studie visar att inget samband mellan kapacitet och borrmotståndet vid jord-bergsondering tycks gå att påvisa. Denna avsaknad av samband kan användas som argument mellan parter för att påvisa att jord-bergsondering inte är lämplig för att beräkna förväntat kapacitet. Flera möjliga orsaker till resultatet finns och en är osäkerhet i information som inhämtats från projektens dagböcker. Ytterligare en förklaring kan vara att jord-bergsonderingen inte återspegla de parametrar i jorden som har störst betydelse vid drivning av spontplankor. / Sheet pile walls is a common type of retaining structure and is today the most time and cost effective solution on the market. Sheet pile walls consist of steel sheet piles which often are driven with vibratory equipment. A number of studies have since the beginning of the 21st century investigated which factors that influence the driveability of a sheet pile. But the knowledge about expected production capacity, for an entire project, is still limited and the only indication for difficulties when piling, that is used today, is the occurrence of blocks and firm friction soil. This leads to uncertainties in the planning phase of project which can lead to delays and increased costs. The goal of this work is to enable for estimation of the sheet piling capacity in an early state of projects. The work intends to answer what capacity can be expected when sheet piling and if it is possible to predict this from the parameters evaluated from the soil-rock sounding. To fulfill the goal of this work nine sheet piling project performed by Skanska Sverige AB have been studied. Based on information from diaries and sheet piling protocols, from these projects, the capacities of the sheet piling have been gathered. Gathered data for the capacity have then been connected to the penetration resistance evaluated from the soil-rock sounding to find a possible relationship. The most significant result of this study illustrates that no relationship between the capacity and penetration resistance from soil-rock sounding can be shown. This lack of relationship can be used as an argument between parties to show that soil-rock sounding is not suitable for calculating expected capacity. There are several possible reasons for this result and one is uncertainties in the information gathered from project diaries. Another explanation can be that soil-rock sounding does not reflect the parameters in the soil which has the greatest significance when sheet piling.

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