Sökning: "hard rock"

Visar resultat 1 - 5 av 89 avhandlingar innehållade orden hard rock.

  1. 1. Design fires in underground hard rock mines

    Författare :Rickard Hansen; Haukur Ingason; Håkan Frantzich; Mälardalens högskola; []
    Nyckelord :Design fire; underground; hard rock mine; vehicle fire; smoke spread; Energy- and Environmental Engineering; energi- och miljöteknik;

    Sammanfattning : During several decades considerable research activities have been conducted with respect to fires in coal mines, but the research activities with respect to hard rock mines have been limited. As the hard rock mines are getting more complex the need for deeper understanding of fires in underground hard rock mines are getting more in demand. LÄS MER

  3. 2. Time dependent material properties of shotcrete for hard rock tunnelling

    Författare :Lars Elof Bryne; Anders Ansell; Wolfgang Kusterle; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Shotcrete; rock; granite; bond strength; compressive strength; pullout testing; failure modes; interfacial transition zone; micro structure; ettringite; set accelerator; shrinkage; drains; glass fibres; laboratory testing; tunnels tunnelling;

    Sammanfattning : In this thesis different mechanical properties for shotcrete (sprayed concrete) such as compression strength, bond strength, bending tensile strength, elastic modulus, free and restrained shrinkage as a function of its age was investigated. One of the main issues was to investigate the difference between ordinary cast concrete and shotcrete. LÄS MER

  4. 3. Groundwater resources in hard rock coastal terrains : Insights into heterogeneity and spatial variability

    Författare :Robert Earon; Bo Olofsson; Okke Batelaan; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Crystalline Rock; Groundwater Balance; Kinematic porosity; Groundwater Recharge; Water Security; Coastal Aquifer; Land and Water Resources Engineering; Mark- och vattenteknik;

    Sammanfattning : Challenges regarding water security in hard rock coastal regions with limited soil cover are: a seasonal absence of recharge during times of peak residency, heterogeneity and variability of the fracture network, close proximity to saline water sources and spatially inconsistent storage and extraction. In areas where it is not feasible to connect residents to municipal water systems, a better understanding of the resilience of reservoirs is needed. LÄS MER

  5. 4. Mechanical and Hydromechanical Behaviour of Hard Rock Joints. A laboratory study

    Författare :Roger Olsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; laboratory shear tests; constant normal stiffness; rock mechanics; hydromechanical behaivour; rock joints; replicas;

    Sammanfattning : As a consequence of rock engineering works, the rock mass will deform due to stress changes. Most deformation occurs in the rock joints, in form of normal and shear strains. These deformations will also change the void geometry and thereby the joint aperture and fluid flow. LÄS MER

  7. 5. Structural behaviour of shotcrete in hard rock tunnels

    Författare :Andreas Sjölander; Anders Ansell; Richard Malm; Fredrik Johansson; Eivind Grøv; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; shotcrete; structural behaviour; material models; rock support; bond strength; fibre-reinforcement; Concrete Structures; Betongbyggnad;

    Sammanfattning : Tunnels in hard and jointed rock are normally excavated in an arch shape to enable the rock mass to support its weight. Since the beginning of the 1980's, fibre reinforced shotcrete (FRS) in combination with rock bolts have been the dominating support method for hard rock tunnels. LÄS MER