Endre søk
Begrens søket
1 - 12 of 12
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Bernander, Stig
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Kullingsjö, Anders
    Skanska Teknik, Göteborg, Chalmers University of Technology.
    Gylland, Anders K
    Multiconsult, Norwegian University of Science and Technology (NTNU), Trondheim.
    Bengtsson, Per-Evert
    Statens Geotekniska Institut, Linköping, PEB Geoteknik.
    Pusch, Roland
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Olofsson, Jan
    Skanska Sverige AB, Skanska Teknik, Göteborg.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Downhill Progressive Landslides in Long Natural Slopes: Triggering Agents and Landslide Phases modeled with a Finite Difference Method2016Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 53, nr 10, s. 1565-1582Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A large landslide in Tuve (Gothenburg, Sweden 1977) initiated the development of a model for slope stability analysis taking the deformation-softening of soft sensitive clays into consideration. The model studies triggering agents and five phases in progressive slope failure are identified: (1) in-situ, (2) disturbance, (3) unstable ‘dynamic’, (4) transitory (or permanent) equilibrium, and (5) ‘global’ failure. The clay resistance in these phases may differ widely; mostly due to different rates of loading. Two time dependent failure criteria are defined: (i) the triggering load condition in the disturbance Phase (2), and (ii) the transitory equilibrium in Phase (4), indicating whether minor downhill displacements or a veritable landslide catastrophe will occur. The analysis explains why downhill landslides tend to spread over vast areas of almost horizontal ground further down-slope. The model has been applied to landslides in Scandinavia and Canada. Three case studies are briefly discussed. The model is a finite difference approach, where local downhill deformations caused by normal forces is maintained compatible with deviatory shear deformations above the potential (or the established) failure surface. Software and an easy-to-use spreadsheet are introduced as well as recent developments. See also Video Abstract.

  • 2.
    Bhanbhro, Riaz
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Edeskär, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Effect of Particle Size On Mechanical Properties and Particle Breakage of Tailings2017Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tailings material can have different material properties depending upon the type of ore and ore refining process and particle size distribution. Tailings dams are constructed as walk away solutions. Staged construction of tailings dams may lead to breakage of particles in subsequent layers resulting in change in particle sizes of material. This may lead to change in strength parameters upon change in particle sizes. This paper presents the direct shear tests performed on tailings material from a tailings dam. Remolded samples were manufactured in laboratory. The tailings material is separated in to four different particle sizes i.e.1-0.5mm, 0.5-0.25mm, 0.25-0.125mm and 0.125-0.063mm. The tests are performed on different normal stress levels as 50, 100, 150, 300 and 500kPa.The strength parameters are evaluated for each particle size and compared with said particle sizes. In order to study the effect of deposition, the tests are also performed on same material deposited in vertical and horizontal direction. This paper also describes the study of breakage of particles during direct shear tests by sieving the material at the end of each test. 

  • 3.
    Billstein, Mats
    et al.
    Luleå tekniska universitet.
    Svensson, Urban
    Luleå tekniska universitet.
    Johansson, Nils
    Luleå tekniska universitet.
    Application and validation of a numerical model of flow through embankment dams with fractures: Comparisons with experimental data1999Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 36, nr 4, s. 651-659Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The focus of this paper is on the development and validation of a numerical model of flow through simplified embankment dams with fractures. Two laboratory experiments were conducted to provide data for validation of the numerical model, one dealing with steady flow in a Hele-Shaw cell and one with steady flow through a bed of packed glass beads. A horizontal fracture, extending from the upstream boundary to a point within the embankment, was used in both experiments, and it was shown to have a significant influence on the discharge, pressure distribution, height of the seepage face, and free surface profile. Comparisons between numerically determined and experimentally measured results were carried out with respect to the discharge, pressure distribution, height of the seepage face, and free surface profile. In the experiments it is shown that a fracture increases the discharge and that the discharge increases more when a fracture is located far away from the free surface profile than when it is located close to the free surface profile. The height of the seepage face above the tailwater is strongly dependent upon the length of the fracture. The influence on the free surface profile is greater when a fracture is close to the free surface profile than when it is far away from the free surface profile. These effects are also found in the numerical simulations. It is thus concluded that the agreement is generally satisfactory between the experimental and numerical results

  • 4.
    Bowman, Elisabeth T.
    et al.
    Department of Civil and Natural Resources Engineering, University of Canterbury.
    Imre, Bernd
    Institute for Geotechnical Engineering, ETH Zurich.
    Laue, Jan
    Institute for Geotechnical Engineering, ETH Zurich.
    Springman, Sarah M
    Institute of Geotechnical Engineering, ETH Hönggerberg, Zürich, Institute for Geotechnical Engineering, ETH Zurich.
    Experimental modelling of debris flow behaviour using a geotechnical centrifuge2010Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 47, nr 7, s. 742-762Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Physical modelling of debris flows has been carried out in the geotechnical drum centrifuge at ETH Zürich. A new apparatus to model debris flows in the centrifuge is described. The apparatus permits the final reach of a typical debris flow to be modelled within the centrifuge, with unconsolidated material flowing down a slope to deposit as a fan around the drum. Experiments are described for both fixed base conditions and erodible bases. Tests to examine the verification (modelling) of models show that debris flow behaviour is governed mainly by friction and consolidation processes, although some resolution is required between flow behaviour downslope and flow arrest during runout. The results are compared with bulk parameters determined for field-scale debris flows. It is found that some important flow mechanisms, such as contact-dominated behaviour and high pore pressures, are developed that are closer to those developed at fieldscale than tests conducted at 1g. Velocity profiles for erodible beds are compared with a semi-empirical expression derived for experimental debris flows at 1g. Normalized velocity profiles are found to be in agreement; however, absolute velocities differ from those predicted. Scaling, the limitations of the apparatus, and potential for future work are discussed

  • 5.
    Edelbro, Catrin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Sjöberg, Jonny
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Dahner-Lindqvist, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Malmgren, Lars
    Prediction and follow-up of failure and fallouts in footwall drifts in the Kiirunavaara mine2012Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 49, nr 5, s. 546-559Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A likely result of changes in rock stresses due to progressing mining is an increased number of compressive stress–induced failures. This paper presents the results from numerical analysis and observations of stress-induced fallouts infootwall drifts in the Kiirunavaara underground mine. A brittle-plastic cohesion-softening friction-hardening (CSFH) material model was used for simulating brittle fallouts. To account for mining-induced stress changes, the local model stress boundary conditions were extracted from a global model. The rock mass properties were based on field observations in the footwall drifts as well as on results from laboratory testing. A multi-stage analysis was carried out to gradually change the stresses to simulate mining progress. A parametric study was conducted in which strength properties, location, and shape of the footwall drift were varied. Yielded elements and maximum shear strain were used as damage and fallout indicators. The modelling results were sensitive to the shape of the drift. The location of the predicted fallouts was in good agreement with the location of observed fallouts for the case in which the drift roof was simulated flatter than the theoretical cross section. The results indicate that the true shape of the drift is different from the planned one

  • 6.
    Locat, Ariane
    et al.
    Département de Génie Civil, Université Laval, Pavillon Adrien-Pouliot.
    Leroueil, Serge
    Département de Génie Civil, Université Laval, Pavillon Adrien-Pouliot.
    Bernander, Stig
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Demers, Denis
    Ministere des Transports du Quebec.
    Jostad, Hans Petter
    Norges Geotekniske Institutt, NGI.
    Quehb, Lyes
    LVM - Technisol / Dessau.
    Progressive failures in eastern Canadian and Scandinavian sensitive clays2011Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 48, nr 11, s. 1696-1712Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Observations from past events are used to show that the concept of progressive failure may explain translational progressive landslides and spreads — large landslides occurring in sensitive clays. During progressive failure, the strain-softening behaviour of the soil causes unstable forces to propagate a failure surface further in the slope. Translational progressive landslides generally take place in long, gently inclined slopes. Instability in a steeper upslope area is followed by redistribution of stress, which increases earth pressure further downslope. Passive failure may therefore occur in less-inclined ground, heaving the soil. Spreads are usually trigged by erosion of a deposit having a higher angle near the toe. Instability starts near the toe of the slope and propagates into the deposit, reducing earth pressure. This may lead to the formation of an active failure with dislocation of the deposit into horsts and grabens. The failure mechanism of both types of landslides is controlled by the stresses in the slope and the stress–strain behaviour of the soil. The mechanism presented explains the sensitivity of a slope to minor disturbances and the resulting high retrogressions observed for such landslides in Scandinavia and eastern Canada.

  • 7.
    Makusa, Gregory
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mácsik, Josef
    Strategic services & Sustainable Development at Ecoloop, Luleå tekniska universitet, SCC/Ramböll, Ecoloop, Stockholm.
    Holm, Göran
    Statens Geotekniska Institut, Linköping, Luleå tekniska universitet.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    A laboratory test study on effect of freeze–thaw cycles on strength and hydraulic conductivity of stabilized dredged sediments2016Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 53, nr 6, s. 1038-1045Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dredged sediments with initial water content between 200% and 400% were treated with single and composite binders. Samples were subjected to open and semi-closed freeze-thaw (f-t) cycles to investigate the impact of f-t cycling on hydraulic conductivity (HC) and unconfined compressive strength (UCS). A grace period (GP) for thaw consolidation is included to assess healing potential of the affected stabilized mass. The findings of this study show that the impact of f-t cycles depend on initially achieved UCS and HC values prior to the f-t cycling and time of testing after f-t cycles. The HC of specimens with initially UCS value of 87 kPa increased with number of f-t cycles. The UCS values decreased in the range of 50%-80% when specimens were tested directly after the thaw period and values decreased in the range of 14%-60% when specimens were tested at the end of GP. The HC of specimens with initial UCS value of 299 kPa remained almost the same. These samples experienced permanent loss in the UCS values, irrespective of time of testing. Detrimental effects of the freezing action on the UCS were greater under semi-closed than open freezing conditions.

  • 8.
    Makusa, Gregory Paul
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Bradshaw, Sabrina, L.
    University of Wisconsin-Madison.
    Berns, Erin
    University of Wisconsin-Madison.
    Benson, Craig, H.
    University of Wisconsin-Madison.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Freeze-thaw cycling and the hydraulic conductivity of geosynthetic clay liners concurrent with cation exchange2014Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 51, nr 6, s. 591-598Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tests were conducted to assess the effect of cation exchange coincident with freeze-thaw cycling on the hydraulic conductivity of a geosynthetic clay liner (GCL). GCLs were prehydrated by contact with silica flour moistened with synthetic subgrade pore water and subsequently permeated with a solution representing the pore water in the cover soil over a tailings facility. Control tests were conducted using the same procedure except deionized water (DI) was used as the permeant liquid to preclude cation exchange from the permeant liquid. The GCLs were subjected to 1, 3, 5, 15, and 20 freeze-thaw cycles, and the hydraulic conductivity and exchange complex were determined after each freeze-thaw increment to assess chemical changes that occurred during freezing, thawing, and permeation. GCLs undergoing freeze thaw cycling experienced little to no cation exchange until 15 freeze-thaw cycles. After 20 freeze-thaw cycles, however, 50% of the sodium (Na) initially in the exchange complex was replaced by calcium (Ca). Dissolution of calciate within the bentonite is a likely source of the Ca. Hydraulic conductivity of GCLs exposed to freeze-thaw cycling was lower than the hydraulic conductivity of a new GCL permeated with DI water (< 2.2x10-11 m/s). A small increases in hydraulic conductivity (~2.3 times), which may have been caused by cation exchange, occured at 15 and 20 freeze-thaw cycles but the hydraulic conductivity remained below that obtained by direct permeation with DI water.

  • 9.
    Ormann, Linda
    et al.
    Dam Safety Forum, Power Division Renewable Energy.
    Zardari, Muhammad Auchar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mattsson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Bjelkevik, Annika
    Tailings Consultants Scandinavia AB.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Numerical analysis of strengthening by rockfill embankments on an upstream tailings dam2013Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 50, nr 4, s. 391-399Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The consolidation process could be slow in an upstream tailings dam; therefore, the stability can reduce due to an increase in excess pore pressures when the dam is raised. The safety of the dam can be enhanced by constructing rockfill berms on the downstream side. This paper presents a case study on the strengthening of an upstream tailings dam with rockfill berms. The finite element analyses were performed for modelling the staged construction of the dam and for optimizing the volume of the rockfill berms. The dam was raised in 11 stages; each stage consisting of a raising phase and a consolidation phase. The study shows that the slope stability of the dam reduced due to an increase of excess pore pressures during the raising phase. The stability of the dam was successfully improved by utilizing rockfill berms as supports on the downstream side. A technique has been presented to minimize the volume of the rockfill berms so that the required stability can be achieved at minimum cost. This paper shows that the finite element method can be a useful tool for modelling the consolidation behaviour of an upstream tailings dam and minimizing the volume of the rockfill berms that may be needed to maintain the stability of the dam during staged construction.

  • 10.
    Pusch, Roland
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mineral-water interactions and their influence on the physical behavior of highly compacted NA bentonite1982Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 19, nr 3, s. 381-387Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Na-bentonite is being considered as an engineering barrier for surrounding radioactive waste disposal sites, due to its low permeability and ion diffusivity, and its self-healing ability through swelling. These properties are due to mineral-water interactions that yield a microstructural pattern with very narrow passages and a low average mobility of interparticle water molecules at high bulk densities. The physical and mechanical behaviour of dense Na-bentonite are discussed.

  • 11.
    Pusch, Roland
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Thixotropic stiffening of clay consolidated in the laboratory1982Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 19, nr 4, s. 517-521Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reserve strength and brittle behavior are characteristic of many soft clays that are normally consolidated from a geological point of view. If such strengthening is associated with creep, it should also take place in structurally disturbed clay that is left to rest under undrained as well as drained conditions, and this was investigated in the study reported in this paper. Samples of natural, undisturbed and artificially produced clays were consolidated under a pressure corresponding to twice the preconsolidation pressure, and were left to rest under reduced pressure and drained conditions. The samples were sheared under undrained conditions and it was observed that the strain at failure decreased and that the shear modulus increased with the time elapsed, thus proving that thixotropic stiffening exceeded the softening due to volume increase.

  • 12.
    Viklander, Peter
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Permeability and volume changes in till due to cyclic freeze/thaw1998Inngår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 35, nr 3, s. 471-477Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A fine-grained nonplastic till was compacted in the laboratory in three types of rigid wall permeameters, having a volume of 0.4, 1.5, and 25 dm3, respectively, and, was thereafter exposed to a maximum of 18 freezing and thawing cycles. The permeabilities in the vertical direction of saturated samples were measured in unfrozen soil as well as in thawed soil. The results show that the permeabilities changed after freezing and thawing. The magnitude of the changes in this study were in the range 0.02-10 times after freeze/thaw compared with the unfrozen soil. Soil exhibited volume changes subsequent to freeze/thaw. The volume typically decreased for an initially loose soil and increased for a dense soil. Independent of whether the initial soil structure was loose or dense, a constant `residual' void ratio, eres, was obtained after 1-3 cycles. For the soil investigated, the residual void ratio ranged from 0.31 to 0.40

1 - 12 of 12
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf