Norwegian Geotechnical Institute (NGI) Digital Archive
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1356 research outputs found
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Automatic Mapping and Characterisation of Linear Depositional Bedforms: Theory and Application Using Bathymetry from the North West Shelf of Australia
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Assessing the Persistence and Mobility of Organic Substances to Protect Freshwater Resources
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Development of an enhanced CPT system for Dogger Bank
Get PDFAn enhanced seafloor CPT system has been developed to support completion of the soil investigation campaign for Dogger Bank. This enhanced system has a demonstrable and significant performance increase over standard seafloor CPT systems; capable of pushing through dense sand layers with qc>100 MPa and through tens of meters of very stiff clays. At Dogger Bank, this enhanced system has enabled CPT penetrations of more than 40 m below seafloor, in soils where standard systems could only average in the twenties. The system enhancement has been achieved through the application and adaption of techniques well known in the geotechnical industry (water lubrication and water injection), but which have never before been combined in an offshore seafloor CPT system. The performance of the enhanced CPT system has enabled a reliance on seafloor CPTs to acquire data to beyond monopile toe depths, therefore removing absolute reliance on boreholes to acquire data at turbine locations and facilitating the fast and efficient development of a geotechnical design basis.Development of an enhanced CPT system for Dogger BankpublishedVersio
A first step towards a IoT-based local early warning system for an unsaturated slope in Norway
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Identifying persistent, mobile and toxic (PMT) organic compounds detected in shale gas wastewater
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Large diameter laterally loaded piles in sand: Numerical evaluation of soil stress paths and relevance of laboratory soil element testing
Get PDFThis paper uses 3D numerical analyses to investigate the stress path experienced by soil elements around large diameter piles in sand subjected to monotonic drained lateral loading. Inspection of the loading-induced stresses in the soil revealed the multiaxial nature of these stress paths, which are characterised by rotation of one or more principal stress axes. Based on the outcome of the finite element analyses, typical stress paths for different soil elements around the piles are extracted. Such stress paths are then evaluated against those enabled by conventional and advanced laboratory soil element testing. It is found that a combination of tests in the Hollow Cylinder Torsional Apparatus (HCTA) can reproduce most features of the numerically identified stress paths for soil elements around the pile. Unavoidable limitations in laboratory testing are discussed as well as the major challenge in replicating the loading direction with respect to the material axes. Some guidance for the experimental implementation of these stress paths in the HCTA are provided as well as a discussion on the use of conventional experimental equipment, such as the conventional triaxial or simple shear apparatus.Large diameter laterally loaded piles in sand: Numerical evaluation of soil stress paths and relevance of laboratory soil element testingpublishedVersio
Extreme precipitation induced landslide event on 30 July 2019 in Jølster, western Norway
Get PDFA torrential rain event struck western Norway on Tuesday 30 July 2019. Most severely affected was the Jølster community, where numerous landslides and floods damaged public infrastructure and private property. This resulted in one fatality, 150 people evacuated from the area and the closure of Highway E39, the main coastal transport route in Norway. Weather radar data reveal large spatial and temporal variations in rainfall intensity and areas with highest intensities correspond to observed shallow landslide clusters where the 200-year rainfall event magnitude was clearly exceeded. The majority of 120 shallow landslide source areas share common characteristics: they are situated above or at the tree line, in thin to very thin soil, in contact with the bedrock or large boulders and in rather steep terrain (>30 degrees). Several lines of evidence suggest that soil in the source areas was not fully saturated, but instead failed due to locally high porewater pressures as short and intense rainfall on dry ground led to water infiltration through open cracks in the surface cover, and commonly at soil-bedrock or soil-boulder contacts. The most far-reaching debris flows of the event have steep upper transport areas, in places with cliff sections, which created sufficient flow-momentum despite small starting volumes. We note that erosion along the flow path was relatively superficial since incomplete soil saturation with depth likely prevented deeper entrainment. Consequently, water-to-solid ratios in the mobilised material was high and the runout possibly longer but less destructive compared to more deep-seated landslide events. This type of summer torrential rain on unsaturated soil require adjustments to how Norwegian society predicts and prepares for shallow landslides triggered during these events, compared with landslides following longer-lasting rainfall.publishedVersio
Deliverable 5.2 Methodology for quantitative modelling of CO2 storage containment risks
No full textThe current state-of-the art for assessing CO2 containment risk relies on qualitative or semi-quantitative methods using bowtie analysis or Layers Of Protection Analysis (LOPA). Whilst these are more than adequate for screening of sites, a fully quantitative method is desirable to support licensing and ongoing management of risk. Such a methos would focus on the probabilistic failure of geological features; and would necessarily take full account of dependent failure of geological barriers, which is a failing of current methods, as well as consider explicitly the uncertainty in supporting failure and consequences data. Building on previous Carbon Capture and Storage (CCS) work and established techniques in the nuclear industry for the quantitative risk modelling of fission product release from containment and, separately, seismic hazards, the aim of this task is to develop and trial a suitable fully quantitative CO2 containment risk evaluation method. The first issue provides an outline of the proposed methodology, which will be trialled, further developed and finalised during the course of the project.European CommissionpublishedVersio
Deliverable D5.3. Work Package 5
No full textGIBV-verktøyet er utviklet gjennom forsknings- og utviklingsprosjektet (FoU) BegrensSkade II som har pågått fra 2017 til 2022. GIBV står for "Ground-work Impact (GI) og Building Vulnerability (BV)". Verktøyet er utviklet for vurdering av risiko for bygningsskade i forbindelse med dype utgravinger og tunneler. Det vil gi en indikasjon på størrelsen av forventede setninger, og i sammenheng med bygningsinfo vil det gi indikasjon på risiko for bygningsskade. Verktøyet egner seg ikke for vurdering av enkeltbygninger, men vil kunne gi ingeniørteamet god oversikt over hvilke bygninger som står i fare for å få setningsskader og hvor det bør gjennomføres mer detaljerte vurderinger. I tillegg til at det raskt utføres setnings- og risikoberegninger for et stort område, presenteres resultatene i kartformat i ArcGIS, noe som gjør det lettere å visualisere og kommunisere konsekvenser av utbyggingen.Norges Forskningsråd
The Research Council of Norwa