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1
Bakkehøi, S., K. Øien, and E. J. Førland. "An Automatic Precipitation Gauge Based on Vibrating-Wire Strain Gauges." Hydrology Research 16, no. 4 (August 1, 1985): 193–202. http://dx.doi.org/10.2166/nh.1985.0015.
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The Norwegian Geotechnical Institute, NGI, has recently developed and tested a new automatic precipitation gauge for rain and snow which can measure accumulated precipitation with a resolution better than 0.1 mm. The gauge, which is a direct weighing device, is based on the use of vibrating-wire strain gauges. NGI's prototype instrument has a capacity of up to 300 mm precipitation before the gauge must be emptied. A new improved version designed by Geonor has a capacity of 600 mm precipitation. A diagram showing the relationship between the automatic observations and the manual measurements is included. In the NGI prototype the precipitation container is suspended from three small steel wires, each of which is in effect the sensing element in a vibrating-wire type strain gauge. When these gauge wires are set into vibration by an electromagnetic exciter, their resonant frequency of vibration is proportional to the square of the tension in the wire. Thus change in the frequency signals is a measure of the change in tension in the wires and correspondingly a measure of the accumulative weight of precipiation in the container. The distance between the precipitaion gauge and the monitoring station can be up to one kilometre without any loss in performance.
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Lunne, T., S. Knudsen, Ø. Blaker, T. Vestgården, J. J. M. Powell, C. F. Wallace, L. Krogh, N. V. Thomsen, G. Yetginer, and R. K. Ghanekar. "Methods used to determine maximum and minimum dry unit weights of sand: Is there a need for a new standard?" Canadian Geotechnical Journal 56, no. 4 (April 2019): 536–53. http://dx.doi.org/10.1139/cgj-2017-0738.
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Known challenges exist with maximum (γdmax) and minimum (γdmin) dry unit weight measurements; the respective dry unit weight results depend very much on the method or standard used. A laboratory testing programme was completed to systematically determine and compare γdmax and γdmin values derived for six different sand types by using different methods. The tested sands contained a wide variety of mineralogical and fines contents. The γdmax and γdmin determinations were performed according to the following methods: British Standards Institution (BS) standards; American Society for Testing and Materials (ASTM) standards; Deutsches Institut für Normung (DIN) standards; Dansk Geoteknisk Forening (DGF) guidelines; Norwegian Geotechnical Institute (NGI), Geolabs, and Fugro proprietary methods. Differences in testing procedures, material requirements for testing, and the effects of soil degradation during testing introduce challenges and large differences in γdmax and γdmin values for each of the six sand types were observed. Therefore, it is concluded that there is a need for the development of new standards for a robust determination of γdmax and γdmin values. Specifically, a standard for determining γdmax is required to consistently obtain results at the upper bound of dry unit weight values for the likely range of sands — without crushing the sand grains.
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Al-Tarhouni, M., P. Simms, and S. Sivathayalan. "Cyclic behaviour of reconstituted and desiccated–rewet thickened gold tailings in simple shear." Canadian Geotechnical Journal 48, no. 7 (July 2011): 1044–60. http://dx.doi.org/10.1139/t11-022.
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A simple-shear apparatus (Norwegian Geotechnical Institute (NGI) type) has been used to investigate the mechanical behaviour of gold tailings under monotonic, cyclic, and post-cyclic loading. Specimens were prepared either by reconstituting the tailings at different water contents or by employing a “dry–wet” preparation technique. The latter technique attempted to simulate a realistic stress history for thickened tailings deposition by preparing the specimen at the pumping water content, and subsequently allowing it to settle and then desiccate to a target water content. Subsequently, these specimens are rewetted and then consolidated. Cyclic resistance ratios for specimens prepared by the dry–wet preparation technique were considerably higher than those of specimens prepared by the standard technique, though there appears to be no advantage in drying the tailings past the shrinkage limit. In general, the tailings could experience significant deformation during cyclic and post-cyclic loading irrespective of whether the monotonic response at a given stress state was contractive or dilative. Shear strength normalized with consolidation pressure, and cyclic resistance ratios, can be plotted as unique functions of void ratio. Post-cyclic strengths require considerable strain to be mobilized. It is recommended that site-specific tolerable strain criteria be adopted to design thickened gold tailings stacks to resist earthquake loading.
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Hestnes, Erik. "A Contribution to the Prediction of Slush Avalanches." Annals of Glaciology 6 (1985): 1–4. http://dx.doi.org/10.3189/1985aog6-1-1-4.
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Slush avalanches, primarily known from uninhabited arctic and mountainous regions, every year cause damage to man and property in Norway. Seeking objective criteria to identify their hazard zones, and methods for their prediction and control, the Norwegian Geotechnical Institute (NGI) has started a research program on these topics.Thirty-four slush avalanches with known locations of crown surface have been investigated with regard to geomorphic and climatic characteristics. Starting zones, crown surfaces and tracks were classified according to geomorphic conditions important to avalanche release and motion.Weak cohesionless snowpacks of coarse grains, and hard layers or crusts of ice in snow cover or on the ground, are critical conditions for slush avalanche release. Intense rain, falling on cohesionless new snow on these substrata, is the most striking feature of current weather situations.The main starting zones were drainage channels, Sloping bogs, depressions and open fields. Channel-like, scar-like or bowl-like features appeared in the snow cover due to avalanche release. Three main types of release were identified: 1) Sudden release from crown surface, 2) drainage of snow-embanked, water-saturated snowfields through narrow outlets and 3) rapid headward growth from first point of release.Enlargements and confinements along the avalanche tracks were caused by distinctly defined features in the tracks.
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Hestnes, Erik. "A Contribution to the Prediction of Slush Avalanches." Annals of Glaciology 6 (1985): 1–4. http://dx.doi.org/10.1017/s0260305500009873.
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Slush avalanches, primarily known from uninhabited arctic and mountainous regions, every year cause damage to man and property in Norway. Seeking objective criteria to identify their hazard zones, and methods for their prediction and control, the Norwegian Geotechnical Institute (NGI) has started a research program on these topics. Thirty-four slush avalanches with known locations of crown surface have been investigated with regard to geomorphic and climatic characteristics. Starting zones, crown surfaces and tracks were classified according to geomorphic conditions important to avalanche release and motion. Weak cohesionless snowpacks of coarse grains, and hard layers or crusts of ice in snow cover or on the ground, are critical conditions for slush avalanche release. Intense rain, falling on cohesionless new snow on these substrata, is the most striking feature of current weather situations. The main starting zones were drainage channels, Sloping bogs, depressions and open fields. Channel-like, scar-like or bowl-like features appeared in the snow cover due to avalanche release. Three main types of release were identified: 1) Sudden release from crown surface, 2) drainage of snow-embanked, water-saturated snowfields through narrow outlets and 3) rapid headward growth from first point of release. Enlargements and confinements along the avalanche tracks were caused by distinctly defined features in the tracks.
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Vucetic, Mladen. "Normalized behavior of clay under irregular cyclic loading." Canadian Geotechnical Journal 27, no. 1 (February 1, 1990): 29–46. http://dx.doi.org/10.1139/t90-004.
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A systematic analysis of the undrained stress–strain behavior of clay under irregular cyclic simple shear loading is presented. Seven specimens of an offshore clay consolidated to overconsolidation ratios of 1, 2, and 4 were subjected to different combinations of variable and nonsymmetric cyclic amplitudes using the Norwegian Geotechnical Institute (NGI) direct simple shear device. The test results show that (1) the behavior under such loads is influenced by several different factors, (2) among these factors the loading history and cyclic stiffness degradation are predominant, and (3) the irregular cyclic loading stress–strain curves can be described quite well by five rules that incorporate only these two factors. Four out of these five rules are the extensions of two original and two extended Masing rules to the behaviour of cyclically degrading clay. The fifth rule is new. The effects of the S-shaping of the stress–strain curves and the rate of loading on the applicability of the rules are also discussed. The stress–strain curves are presented in the normalized form with respect to the vertical effective consolidation stress. In this form they show quantitatively the same trends, indicating that such normalization is applicable to irregular cyclic loading. Key words: clay, earthquake loading, laboratory test, ocean soil, overconsolidation, simple shear test, soil dynamics, strain rate effect, repeated loading.
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Karlsrud, Kjell, and Francisco Gabriel Hernandez-Martinez. "Strength and deformation properties of Norwegian clays from laboratory tests on high-quality block samples." Canadian Geotechnical Journal 50, no. 12 (December 2013): 1273–93. http://dx.doi.org/10.1139/cgj-2013-0298.
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It has for a long time been a challenge for the geotechnical profession to determine the true behaviour of clays based on soil sampling and laboratory testing. The main difficulty has been to retrieve sufficiently undisturbed samples that maintain the clay structure and correctly depict the in situ stress–strain and strength behaviour of the clay under any kind of imposed drained or undrained loading conditions. The extent and impact of the disturbance caused by sampling depends on a number of factors, such as the specific sampling equipment and sampling procedures that are used, index properties of the clay (sensitivity and plasticity index in particular), and sampling depth. Experience with laboratory tests on conventional piston samples shows that sample disturbance commonly affects the test results. In the mid 1970s, the University of Sherbrooke developed a special block sampler that was shown to give samples of very high quality. Between 1982 and 2010, the Norwegian Geotechnical Institute (NGI) has used the Sherbrooke block sampler at 22 different sites in Norway and one site in the UK. Two to five block samples were collected at each site, on which oedometer, undrained triaxial, and direct simple shear (DSS) tests were carried out in the laboratory. Essentially all samples tested showed far superior quality as compared to conventional piston samples. It was therefore considered to be valuable to summarize test results obtained on such high-quality samples, as presented herein. Deformation and strength parameters from individual tests are summarized and compared against index data for the different clays tested. This has resulted in a series of correlation diagrams. The index parameters found of most relevance to use as correlation parameters are the natural water content and clay sensitivity. The latter is expressed in two categories: medium to low sensitivity (St < 15) and high sensitivity (St > 15). The overconsolidation ratio is another key parameter. The correlation diagrams presented include the following: (i) pre-consolidation pressure, compressibility, permeability, and permeability change index as derived from oedometer tests; (ii) normalized peak and post-peak shear strength, peak effective friction angle, stiffness, and strain at failure from undrained triaxial and DSS tests. When design analyses are to be based on the results of tests on high-quality block samples, as compared to conventional piston samples of poorer quality, it is important to ensure that the end result complies with past semi-empirical experiences.
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Ladanyi, Branko, Tom Lunne, Pierre Vergobbi, and Bernard Lhuillier. "Predicting creep settlements of foundations in permafrost from the results of cone penetration tests." Canadian Geotechnical Journal 32, no. 5 (October 1, 1995): 835–47. http://dx.doi.org/10.1139/t95-080.
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As a joint research project sponsored by the French–Norwegian Foundation for Scientific and Industrial Research, the Norwegian Geotechnical Institute, Geodia/Geocean, and École Polytechnique have carried out in the summer of 1990 a series of special in situ pressuremeter and cone penetration tests at a permafrost site in Longyearbyen, Svalbard. The purpose of the testing program was to compare the results of the two different field testing methods and to check the potential of such methods for serving as a basis for prediction of the behaviour of foundations in permafrost. As pressuremeter test results have been presented in a previous publication, this paper shows only the results of cone penetration tests and their interpretation in terms of strength and creep parameters of the frozen soil. Subsequently, the same data are used to predict the behaviour under long-term axial load of two prefabricated and one cast-in-place concrete pile that were tested by the Selmer Furuholmen Anlegg A.S. in cooperation with the Norwegian Geotechnical Institute at the same site for 3 years. Key words : permafrost, cone penetration tests, piles field loading tests, creep settlement.
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Kontoes, Charalampos, Constantinos Loupasakis, Ioannis Papoutsis, Stavroula Alatza, Eleftheria Poyiadji, Athanassios Ganas, Christina Psychogyiou, Mariza Kaskara, Sylvia Antoniadi, and Natalia Spanou. "Landslide Susceptibility Mapping of Central and Western Greece, Combining NGI and WoE Methods, with Remote Sensing and Ground Truth Data." Land 10, no. 4 (April 12, 2021): 402. http://dx.doi.org/10.3390/land10040402.
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The exploitation of remote sensing techniques has substantially improved pre- and post- disaster landslide management over the last decade. A variety of landslide susceptibility methods exists, with capabilities and limitations related to scale and spatial accuracy issues, as well as data availability. The Interferometric Synthetic Aperture Radar (InSAR) capabilities have significantly contributed to the detection, monitoring, and mapping of landslide phenomena. The present study aims to point out the contribution of InSAR data in landslide detection and to evaluate two different scale landslide models by comparing a heuristic to a statistical method for the rainfall-induced landslide hazard assessment. Aiming to include areas with both high and low landslide occurrence frequencies, the study area covers a large part of the Aetolia–Acarnania and Evritania prefectures, Central and Western Greece. The landslide susceptibility product provided from the weights of evidence (WoE) method proved more accurate, benefitting from the expert opinion and the landslide inventory. On the other hand, the Norwegian Geological Institute (NGI) methodology has the edge on its immediate implementation, with minimum data requirements. Finally, it was proved that using sequential SAR image acquisitions gives the benefit of an updated landslide inventory, resulting in the generation of, on request, updated landslide susceptibility maps.
10
Martinelli, M. "A test of the avalanche runout equations developed by the Norwegian Geotechnical Institute." Cold Regions Science and Technology 13, no. 1 (October 1986): 19–33. http://dx.doi.org/10.1016/0165-232x(86)90004-2.
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Lied, K., F. Sandersen, and R. Toppe. "Snow-Avalanche Maps for use by the Norwegian Army." Annals of Glaciology 13 (1989): 170–74. http://dx.doi.org/10.3189/s0260305500007837.
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Mapping of areas exposed to avalanche hazard for the Norwegian Army was started by the Norwegian Geotechnical Institute in 1986. The background to this mapping is that large-scale military exercises are held annually in northern Norway, in terrain where there is a high danger of avalanche activity. Avalanche areas are divided into two zones: potential starting zones, and potential run-out zones. All potential avalanche areas are indicated on maps, and mapping is carried out by computer using a terrain model and digital maps. An interactive graphic work station is used to outline danger areas. Starting and run-out zones are identified by using terrain parameters which may be extracted from digital maps. The usual scale of the avalanche maps is 1 : 50 000, with 20 m contour intervals.
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Lied, K., F. Sandersen, and R. Toppe. "Snow-Avalanche Maps for use by the Norwegian Army." Annals of Glaciology 13 (1989): 170–74. http://dx.doi.org/10.1017/s0260305500007837.
Full textAbstract:
Mapping of areas exposed to avalanche hazard for the Norwegian Army was started by the Norwegian Geotechnical Institute in 1986. The background to this mapping is that large-scale military exercises are held annually in northern Norway, in terrain where there is a high danger of avalanche activity. Avalanche areas are divided into two zones: potential starting zones, and potential run-out zones. All potential avalanche areas are indicated on maps, and mapping is carried out by computer using a terrain model and digital maps. An interactive graphic work station is used to outline danger areas. Starting and run-out zones are identified by using terrain parameters which may be extracted from digital maps. The usual scale of the avalanche maps is 1 : 50 000, with 20 m contour intervals.
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Schreiber, Helmut, Walter L. Randeu, Horst Schaffhauser, and Lambert Rammmer. "Avalanche dynamics measurement by pulsed Doppler radar." Annals of Glaciology 32 (2001): 275–80. http://dx.doi.org/10.3189/172756401781819021.
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AbstractThis paper presents the application of a pulsed Doppler radar for the measurement of dynamic properties of snow and ice avalanches. The instrument was developed and built by the Institute of Communications and Wave Propagation, Technical University Graz, and is operated by the Austrian Institute for Avalanche and Torrent Research (AIATR), Innsbruck. The data acquired by this radar during field campaigns are used to verify and optimize avalanche models and simulation tools. As well as describing the radar’s technical principle, how the dynamic parameters are measured and presented to the user and how these data can be used to accomplish the determination of avalanche velocity and runout distance, the paper deals with the participation of the radar in a successful full-scale snow-avalanche experiment in Ryggfonn, Norway, and evaluates the collected data. This measurement campaign was a joint experiment by the Norwegian Geotechnical Institute, Oslo, and AIATR.
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Budhu, Muniram. "Failure state of a sand in simple shear." Canadian Geotechnical Journal 25, no. 2 (May 1, 1988): 395–400. http://dx.doi.org/10.1139/t88-041.
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The stress state in many practical geotechnical problems is analogous to simple shear strain. However, the devices available to test soil samples in simple shear strain impose nonuniform stress and strain fields. Consequently, the interpretation of results from simple shear tests is often questioned. In this article, results of tests on loose and dense Leighton Buzzard sand from two specially instrumented simple shear devices–Cambridge University's device and a Norwegian Geotechnical Institute type–are used to interpret the failure mode and the failure stress state. The data were obtained from the centre of the samples, a region removed from stress concentrations. Failure was observed to be initiated on vertical planes and occurred very soon after shear displacement was applied. However, neither these vertical planes nor the horizontal planes were the planes of maximum stress obliquity mobilized during the tests. Key words: deformation, failure, loads, sand, shear tests, simple shear, stresses.
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Lunne, Tom, Knut H. Andersen, Han Eng Low, Mark F. Randolph, and Morten Sjursen. "Guidelines for offshore in situ testing and interpretation in deepwater soft clays." Canadian Geotechnical Journal 48, no. 4 (April 2011): 543–56. http://dx.doi.org/10.1139/t10-088.
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Offshore developments for hydrocarbon resources have now progressed to water depths approaching 3000 m, with geotechnical design increasingly focused on soft sediments in the upper 30 m or so of the seabed. Due to the difficulties and high cost in recovering high-quality samples from deepwater sites, there is increasing dependence on in situ testing techniques for determining the geotechnical design parameters. This paper summarizes the findings from a joint industry project, undertaken by the Norwegian Geotechnical Institute and the Centre for Offshore Foundation Systems at The University of Western Australia, on the use of in situ testing for the characterization of deepwater soft soils. The project focused on theoretical and empirical studies for the interpretation of piezocone, T-bar, and ball penetration test data, linking the penetration resistance to shear strengths determined from in situ vane tests and laboratory tests on high-quality samples. Guidelines are summarized for interpreting in situ test data, particularly for estimating intact and remoulded undrained shear strengths from the penetration resistance measured by each type of penetrometer. Suggestions are also given for future development of in situ testing techniques to maximize the potential of in situ testing in characterization of deepwater soft soils.
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Hestnes, Erik. "Slushflow hazard — where, why and when? 25 years of experience with slushflow consulting and research." Annals of Glaciology 26 (1996): 370–76. http://dx.doi.org/10.3189/1998aog26-1-370-376.
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Slushflows — flowing mixtures of water and snow — are a major natural hazard in Norway. Knowledge gathered by the Norwegian Geotechnical Institute during 25 years of slushflow consulting and research is presented. The variation in regional occurrence is described and related to climatic premises and ground conditions. The principal ideas about slushflow release, down-slope propagation and run-out are outlined. They are closely related to the rate and duration of water supply, snowpack properties and geomorphic factors. Slushflow release is caused by basal shear failure aided by water pressure to cause loss of basal support and finally tensile failure through the snowpack. Our methods of hazard evaluation and acute-hazard prediction and warning are summarized, including the estimation of water supply based on meteorological data. The results of a worldwide questionnaire on slushflows, literature studies and scientific contacts, indicate that slushflows occur in all countries having a seasonal snow cover and that the results of our studies in Norway have a general validity.
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Hestnes, Erik. "Slushflow hazard — where, why and when? 25 years of experience with slushflow consulting and research." Annals of Glaciology 26 (1998): 370–76. http://dx.doi.org/10.1017/s0260305500015111.
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Slushflows — flowing mixtures of water and snow — are a major natural hazard in Norway. Knowledge gathered by the Norwegian Geotechnical Institute during 25 years of slushflow consulting and research is presented. The variation in regional occurrence is described and related to climatic premises and ground conditions. The principal ideas about slushflow release, down-slope propagation and run-out are outlined. They are closely related to the rate and duration of water supply, snowpack properties and geomorphic factors. Slushflow release is caused by basal shear failure aided by water pressure to cause loss of basal support and finally tensile failure through the snowpack. Our methods of hazard evaluation and acute-hazard prediction and warning are summarized, including the estimation of water supply based on meteorological data. The results of a worldwide questionnaire on slushflows, literature studies and scientific contacts, indicate that slushflows occur in all countries having a seasonal snow cover and that the results of our studies in Norway have a general validity.
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Ng, Charles W. W., Clarence E. CHOI, Haiming LILU, Sunil Poudyal, Aastha Bhatta, W. A. Roanga K. De Silva, and Raymond W. M. Cheung. "Class A Prediction Symposium on Debris Flow Impact Forces on Single and Dual Barriers." HKIE Transactions 30, no. 1 (July 19, 2023): 63–82. http://dx.doi.org/10.33430/v30n1thie-2022-0039.
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Over recent years, significant advances have been made in the modelling of the impact dynamics between debris flows and single and dual rigid and flexible barriers. Numerical tools and analytical formulations have been proposed to predict the impact force, runup height, barrier deformation, and overflow and landing dynamics. However, there remains a dearth of well-recognised tools that can be used in routine engineering design practice because their reliability is unclear. On 8 and 9 May 2022, a virtual Class A Prediction Symposium on Debris Flow Impact Forces on Single and Dual Barriers was held to evaluate the reliability of existing design tools and identify areas for improvement to advance the current state of barrier design. The symposium was organised by The Hong Kong University of Science and Technology, Norwegian University of Science and Technology, Institute of Mountain Hazards and Environment of the Chinese Academy of Sciences, and the Geotechnical Engineering Office of the Civil Engineering and Development Department of the HKSAR Government. This paper summarises the existing research on flow-barrier interaction, and details of the symposium, including the prediction cases and results, roundtable discussion, and future research directions.
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Nicu, Ionut Cristi, Luigi Lombardo, and Lena Rubensdotter. "Preliminary assessment of thaw slump hazard to Arctic cultural heritage in Nordenskiöld Land, Svalbard." Landslides 18, no. 8 (May 8, 2021): 2935–47. http://dx.doi.org/10.1007/s10346-021-01684-8.
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AbstractPermafrost-dependent landslides occur in a range of sizes and are among the most dynamic landforms in the Arctic in the warming climate. Retrogressive thaw slumps (RTSs) are enlarging landslides triggered by thawing and release of excess water from permafrost ground ice, causing smaller or larger collapses of ground surface, which in turn exposes new permafrost to rapid thawing and collapse. In this study, a preliminary assessment of previous thaw slump activity in Nordenskiöld Land area of Svalbard is made based on remote sensing digitisation of 400 slump-scar features from aerial images from the Norwegian Polar Institute (NPI). RTS properties and distribution are analysed with an emphasis on their implications for the preservation of the Svalbard’s cultural heritage (CH). Our analysis shows that the areas where RTS scars and CH co-exist in Nordenskiöld Land are, at present, limited and cover mainly areas distributed along north-west (Colesbukta, Grønfjorden, Kapp Starostin), north-east (Sassendalen and Sassenfjorden) and south-west (Van Muydenbukta) coastlines. Taking into consideration the preliminary aspect of this inventory and study, it can be stated that for now, RTS and CH sites do not have a high level of co-existence, except for eight sites which are located at less than 100 m to a RTS and one site that is located inside a currently inactive slump-scar. Further mapping of RTS will be undertaken in order to have a complete picture of these climate triggered landslides potentially threatening the Arctic CH. The results of this study, even if preliminary, can be used by local authorities and stakeholders in prioritising future documentation and mitigation measures and can thus present a powerful tool in disaster risk reduction.
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Larsen, Jan Otto. "Snow-creep forces on masts." Annals of Glaciology 26 (1998): 19–21. http://dx.doi.org/10.3189/1998aog26-1-19-21.
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Since 1975, the Norwegian Geotechnical Institute has performed field investigations of snow-creep forces on masts at the research site in Grasdalen, Stryn mountains in Norway. Two poles, with diameters of 419 and 219 mm, respectively, were erected at the site together with a retaining structure. On both poles, strain gauges were mounted in pairs every 0.5 m to find the axial stresses and the moments in different sections. In the middle section of the retaining structure, the beams and supporters were instrumented to obtain measurements of the strains and stresses. Snow glide was controlled by glide shoes mounted at the rock surface above the structures.During the winter, snow profiles were made systematically; these included measurements of snow depth, density and temperature, and observations of snow type and moisture content. By relating the measured stresses and moments in the structures to the snow depth, it was possible to find the snow-pressure distribution. A comparison of the snow pressures with the “Body force index” (product of snow depth h, density ρ and acceleration due to gravity g), show a close relationship for the wall element. For the pole elements, the snow temperature during the winter is an added factor of high importance and the highest pressures on these elements occur in winters with long periods of 0°C isothermal snowpack.
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Larsen, Jan Otto. "Snow-creep forces on masts." Annals of Glaciology 26 (1998): 19–21. http://dx.doi.org/10.1017/s0260305500014476.
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Since 1975, the Norwegian Geotechnical Institute has performed field investigations of snow-creep forces on masts at the research site in Grasdalen, Stryn mountains in Norway. Two poles, with diameters of 419 and 219 mm, respectively, were erected at the site together with a retaining structure. On both poles, strain gauges were mounted in pairs every 0.5 m to find the axial stresses and the moments in different sections. In the middle section of the retaining structure, the beams and supporters were instrumented to obtain measurements of the strains and stresses. Snow glide was controlled by glide shoes mounted at the rock surface above the structures.During the winter, snow profiles were made systematically; these included measurements of snow depth, density and temperature, and observations of snow type and moisture content. By relating the measured stresses and moments in the structures to the snow depth, it was possible to find the snow-pressure distribution. A comparison of the snow pressures with the “Body force index” (product of snow depthh,densityρand acceleration due to gravityg), show a close relationship for the wall element. For the pole elements, the snow temperature during the winter is an added factor of high importance and the highest pressures on these elements occur in winters with long periods of 0°C isothermal snowpack.
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von der Tann, Loretta, Dipanjan Basu, Stefan Ritter, Paul Sverdrup Capellen, and Ingvild Fladvad Størdal. "Sustainability in geotechnical engineering – what does it mean and why does that matter?" Proceedings of the Institution of Civil Engineers - Engineering Sustainability, January 3, 2023, 1–11. http://dx.doi.org/10.1680/jensu.22.00076.
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The aspiration to act in a more sustainable manner has become a guiding principle across many aspects of life. Yet, sustainability is still often perceived as poorly defined, and there are diverse opinions on what the implications of sustainability for the everyday practice of geotechnical engineers are. On this background, this paper presents a survey conducted at the Norwegian Geotechnical Institute (NGI) in the beginning of 2021 that engaged a group of geotechnical engineers with the fundamental question as to how the concept of sustainability relates to geotechnical engineering. The Q-methodology, a mixed method approach, was applied to analyse different perspectives on sustainability in geotechnical engineering as inferred from the survey results. Three distinct perspectives were revealed that have a focus on (a) striving a balance between human action and nature, (b) mitigating adverse impacts of geotechnical projects, and (c) reducing resource use. Two of the perspectives considered the development of sustainability assessment tools as the most relevant means of working towards sustainable geotechnical practices whilst the third perspective considered multidisciplinary collaboration and research as more important. Reflection on these perspectives can help the development of future tools and strategies, provide a direction for future research, and contribute to a more sustainable geotechnical engineering practice.
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"886162 Oedometer testing at the Norwegian Geotechnical Institute." International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts 25, no. 6 (December 1988): 281. http://dx.doi.org/10.1016/0148-9062(88)91150-3.
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Ozturk, Baturalp, Antonio Kodsy, Youssef Bazi, and Magued G. Iskander. "Efficacy of Several Design Methods for Predicting the Axial Compressive Capacity of Piles." Transportation Research Record: Journal of the Transportation Research Board, April 4, 2023, 036119812311583. http://dx.doi.org/10.1177/03611981231158335.
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A variety of design methods for determining piles’ axial compressive load capacity are routinely employed in current practice. These range from methods specified in building codes to proprietary methods developed and employed by an assortment of engineering firms. In this study, the performance of eight commonly used design methods was evaluated using a database of 505 load tests and associated geotechnical design parameters compiled from Professor Olson’s database and that of the Iowa State Department of Transportation. The methods investigated included standard penetration test (SPT)-based methods, such as those recommended by the Federal Highway Administration (FHWA), U.S. Army Corps of Engineers, American Petroleum Institute, and Revised Lambda; and cone penetration test (CPT)-based methods such as those recommended by the Norwegian Geotechnical Institute, Imperial College, Fugro, and University of Western Australia. Pile capacities were calculated using APILE software and were compared with the measured capacities interpreted using the standard Davisson criterion and stored in the databases. The performance of all design methods was evaluated in relation to accuracy, precision, effect of soil type, diameter, and length. Both SPT and CPT methods exhibited similar accuracies, however, CPT-based design methods exhibited significantly better precision compared with SPT-based methods. All methods had shortcomings and appeared to work best under certain conditions, which are documented in this paper. The authors believe that this evaluation will permit practicing engineers and regulating bodies to better understand the efficacy of various design approaches in common use.
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Tremblay-Auger, Frédérique, A. Locat, Serge Leroueil, Denis Demers, and Pierre-Philippe Levasseur. "A rare case of downward progressive failure in eastern Canada: the 1976 Saint-Fabien landslide." Canadian Geotechnical Journal, February 26, 2022. http://dx.doi.org/10.1139/cgj-2019-0831.
Full textAbstract:
The Saint-Fabien landslide occurred in December 1976, 270 km north-east of Quebec City, Canada. The landslide took place in a valley filled with glaciomarine sensitive clays covered by peat bog deposits and presenting an upward hydraulic gradient. Unique features of this event are the ground surface and the failure surface that are both close to the horizontal. In addition, passive and active failure zones were observed in the debris after the landslide, indicating a possible downward progressive failure mechanism, rarely observed in Eastern Canadian clays. Possible triggers of the event are: the continuous exploitation of the peat downslope and/or the roadworks going on along Road 132 at the time of the event, which is crossing the landslide area upslope. Conventional stability analysis for the site gives a factor of safety of 1.43, indicating that limit equilibrium analysis cannot explain the formation of the failure surface observed at Saint-Fabien. The initiation and the propagation of the failure were analysed through 1D numerical modelling using the concept of progressive failure. The methodology consists of two steps: first the calculation of the initial stresses in the slope with the finite element software PLAXIS 2D; and second, the modeling of initiation and propagation of the progressive failure along the potential failure surface with the finite element code BIFURC, developed at the Norwegian Geotechnical Institute.