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Visar resultat 1 - 5 av 40 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Design of grout curtains under dams founded on rock

    Författare :Suihan Zhang; Fredrik Johansson; Johan Funehag; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Grout curtains; Rock grouting; Dams; Erosion; Infilling materials in rock fractures; Injekteringsridåer; Berginjektering; Dammar; Erosion; Sprickfyllnadsmaterial; Soil and Rock Mechanics; Jord- och bergmekanik;

    Sammanfattning : Grouting has long been implemented as a ground improvement technique to reduce the seepage through the rock mass. Grout curtains are usually constructed under dams as a barrier to prevent leakage from the reservoir. So far, the grout curtains under dams have mainly been designed by using an empirical design approach. LÄS MER

  3. 2. Frost-induced deterioration of concrete in hydraulic structures : Interactions between water absorption, leaching and frost action

    Författare :MARTIN ROSENQVIST; Avdelningen för Byggnadsmaterial; []
    Nyckelord :Vattenbyggnader; Dammar; Betong; Cement; Vattenabsorption; Vattenmättnadsgrad; Nedbrytning; Frostbeständighet; Spjälkning; Makroskopisk islinsbildning; Urlakning; Synergi; Hydraulic structures; Dams; Concrete; Cement; Water absorption; Degree of saturation; Deterioration; Frost resistance; Spalling; Macroscopic ice lens growth; Leaching; Synergy;

    Sammanfattning : Frost deterioration of concrete can result in severe consequences to the safety, durability and functionality of a structure since it impairs the strength of the concrete. Frost damage may occur to structures that are in contact with water and subjected to frost action. LÄS MER

  4. 3. Environmental considerations in the planning of large dam projects : a study on Environmental Impact Statements and the Southeastern Anatolia Project

    Författare :Anna Brismar; Jan-Olof Lundqvist; Linköpings universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Atatürk Dam. EIA; ecosystem services; environmental impact; Euphrates River; GAP; hydropower; river system; sustainable development; Tigris River; Turkey; Dammar; Miljöaspekter; Tigris; Turkiet; INTERDISCIPLINARY RESEARCH AREAS; TVÄRVETENSKAPLIGA FORSKNINGSOMRÅDEN;

    Sammanfattning : Large dam projects have played a key role in supporting societal development in the past and continue to be launched, primarily in developing countries. However, large dam projects also cause extensive environmental impacts in the river system, which may reduce the river system's capacity to provide goods, services, and other values apart from those generated by the project. LÄS MER

  5. 4. Leaching of concrete : experiments and modelling

    Författare :Tomas Ekström; Avdelningen för Byggnadsmaterial; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; betongdammar; urlakning; dammar; beständighet; skador; laboratorieförsök; beräkningsmetoder; simulering; beräkningsmodeller;

    Sammanfattning : Many concrete dams, and other concrete structures within the hydropower industry are old and in a more or less severe state of degradation. Leaching is, together with freeze-thaw, the most common degradation problem in Swedish hydraulic concrete structures. LÄS MER

  7. 5. The effects of crayfish on interactions in freshwater benthic communities

    Författare :Per Nyström; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; exotic species; trophic cascades; omnivory; crayfish; Trophic interactions; freshwater; Hydrobiology; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi;

    Sammanfattning : This thesis examines how freshwater crayfish affect community interactions in benthic food webs. I have mainly studied the influence of the introduced signal crayfish (Pacifastacus leniusculus) on littoral communities, but also the influence of the native noble crayfish (Astacus astacus). LÄS MER