Norwegian Geotechnical Institute (NGI) Digital Archive
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The compressible granular collapse in a fluid as a continuum: validity of a Navier-Stokes model with, -rheology
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Weathering Plastics as a Planetary Boundary Threat: Exposure, Fate, and Hazards
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Middle Miocene tropical oligotrophic lagoon deposit sheds light on the origin of the Western Australian coral reef province
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Integrated bedrock model combining airborne geophysics and sparse drillings based on an artificial neural network
Get PDFCost overruns caused by unforeseen geological challenges are commonplace for large infrastructure projects. Thorough ground investigations can reduce this risk, but geotechnical drillings and laboratory test are expensive and time consuming. Airborne electromagnetics (AEM) is a low-cost geophysical method being increasingly used for geotechnical ground investigations. However, extracting engineering parameters from these complex data is challenging. We present a novel approach of extracting depth to bedrock from AEM data using artificial neural networks (ANN) and sparse drillings. Using synthetic models, we test its theoretical performance and analyse sources of error. We find that geological complexity is the main limitation on performance. We also test the algorithm on real field data from a complex geological setting. Results show that ANNs produce bedrock models that rival the accuracy of manual interpretations by experts and that are markedly more accurate than existing automated resistivity model interpretation methods. Using ANN based bedrock interpretation, one needs 2 to 3.5 times fewer geotechnical drillings (i.e., a reduction of 50–70%) in the early phases of a project compared to ground investigations using only borehole data. Further improvements may be possible with strategic planning of drilling campaigns and careful data pre-processing.publishedVersio
Caprock integrity of the Draupne formation, Ling depression, North Sea, Norway
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Laboratory evaluation of mechanical properties of draupne shale relevant for CO<inf>2</inf> seal integrity
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Moving forward in microplastic research: A Norwegian perspective
Get PDFGiven the increasing attention on the occurrence of microplastics in the environment, and the potential envi-ronmental threats they pose, there is a need for researchers to move quickly from basic understanding to applied science that supports decision makers in finding feasible mitigation measures and solutions. At the same time, they must provide sufficient, accurate and clear information to the media, public and other relevant groups (e.g., NGOs). Key requirements include systematic and coordinated research efforts to enable evidence-based decision making and to develop efficient policy measures on all scales (national, regional and global). To achieve this, collaboration between key actors is essential and should include researchers from multiple disciplines, policy-makers, authorities, civil and industry organizations, and the public. This further requires clear and informative communication processes, and open and continuous dialogues between all actors. Cross-discipline dialogues between researchers should focus on scientific quality and harmonization, defining and accurately communi-cating the state of knowledge, and prioritization of topics that are critical for both research and policy, with the common goal to establish and update action plans for holistic benefit. In Norway, cross-sectoral collaboration has been fundamental in supporting the national strategy to address plastic pollution. Researchers, stakeholders and the environmental authorities have come together to exchange knowledge, identify knowledge gaps, and set targeted and feasible measures to tackle one of the most challenging aspects of plastic pollution: microplastic. In this article, we present a Norwegian perspective on the state of knowledge on microplastic research efforts. Norway’s involvement in international efforts to combat plastic pollution aims at serving as an example of how key actors can collaborate synergistically to share knowledge, address shortcomings, and outline ways forward to address environmental challenges.publishedVersio
Numerical hydrogeological modelling of drainage to an excavation
Get PDFThe report regards the conceptual and numerical modelling of drainage scenarios to a planned excavation in a deep clay deposit in Oslo, Norway. The modelling was performed in SEEP/W 2D. Ground investigations indicate that the clay lies directly on top of the bedrock, without a layer of moraine between them. The upper metres of the bedrock is assumed to be weathered and serve as a draining layer. The drainage of groundwater to the excavation along steel core piles, and the mitigating effect of cut-off walls of various lengths, were modelled. There were made several versions of the numerical model, with a variation of conductivity and upstream boundary conditions. The simulation results were compared with empirical pore pressure data presented by the R&D project BegrensSkade I (2012-2015). The simulation results deviated notably from the empirical data, leading to the conclusion that the model itself is unreliable. Although there were found weaknesses with the model that could have been improved and resulted in better compliance, some major uncertainties are considered to remain and to affect the results to a significant degree. The uncertainties are in particular related to the modelling of the (weathered) bedrock conductivity, i.e. how the groundwater flows horizontally, vertically and across large distances within the bedrock joints. The discussion of these uncertainties is only introductory, and there is first of all a need to study the literature in greater detail to find out whether these issues are as important as argued here, and whether researchers already have studied them sufficiently. If the literature study comes to the conclusion that more research is needed, two modelling tasks are proposed with the aim to get a better understanding of how the groundwater flow could have been modelled more realistically in a continuum two-dimensional model.Norges Forskningsråd
Research Council of Norwa
Hydrogeological report
Get PDFNGI is engaged by Norwegian water resources and energy directorate (NVE) to carry out stability analysis of the Åknes rock slide. This report is presenting and analysing the most important investigations and monitoring, such as packer tests and piezometer measurements in both open boreholes and boreholes with packers dividing the borehole in sections. A hydrogeological model is presented.
The main conclusions are:
- Water head on the sliding plane are small, only small peaks up to 3-4 meter over short periods of time are monitored. For most of the boreholes the water table is several meters below the main sliding plane.
- The hydraulic communication in the slope is high. It seems like the hydraulic
system is fed from a bigger area, not only the backscarp.Norges vassdrags- og energidirektorat (NVE