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  • 251.
    Axelsson, Kennet
    Luleå tekniska universitet.
    Kallortsteknikforskning i geoteknik vid University of Alberta och National Research Council of Canada: intryck från studiebesök i januari 19871987Rapport (Annet vitenskapelig)
  • 252.
    Axelsson, Kennet
    et al.
    Luleå tekniska universitet.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Nyström, B.
    Luleå tekniska universitet.
    Sheng, Daichao
    Luleå tekniska universitet.
    On a finite element model for freezing and thawing soil1989Inngår i: Poac 89: 10th International Conference on Port and Ocean Engineering under Artic Conditions, Luleå, Sweden, 12-16 June 1989 / [ed] Lennart Å. Fransson; Kennet B. Axelsson, Luleå: Högskolan i Luleå , 1989, Vol. 1, s. 342-353Konferansepaper (Fagfellevurdert)
  • 253.
    Axelsson, Kennet
    et al.
    Professor emeritus i byggnadskonstruktion vid Uppsala universitet.
    Mattsson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Geoteknik2016Bok (Fagfellevurdert)
    Abstract [sv]

    Geoteknik behandlar jordmaterials mekaniska och tekniska egenskaper, kunskaper som är av betydelse för utförandet av en säker och stabil grundläggning av byggnader och anläggningar. Ämnet stödjer sig på kvartärgeologin, d.v.s. de lösa jordarternas geologi, samt på mekaniken och främst då deformerbara fasta kroppars mekanik. Geoteknik är ett semiempiriskt ämne, d.v.s. provning och erfarenhet ligger också till grund för de metoder som tillämpas.Boken är uppdelad i fyra huvuddelar. I del A ges en introduktion till ämnet samt en återblick på byggnadsgeologin (kvartärgeologin). I del B behandlas jordmaterialläran, d.v.s. jords kemiska och fysikaliska egenskaper vad gäller beståndsdelar, klassificering och strukturell uppbyggnad. Del C behandlar jordmekaniken, d.v.s. mekaniska och hållfasthetstekniska egenskaper hos jord. I del D tillämpas de inhämtade kunskaperna på viktiga geotekniska problemområden såsom bestämning av spännings­tillstånd i jordprofiler, beräkning av byggnaders och anläggningars sättning och geotekniska bärförmåga samt bestämning av jordtryck mot stödkonstruktioner och av jordslänters stabilitet.Geoteknik vänder sig i första hand till studenter på de tekniska hög­s­kolornas program för väg- och vattenbyggnad och samhällsbyggnad samt på högskolornas byggingenjörsprogram.

  • 254.
    Axelsson, Kennet
    et al.
    Luleå tekniska universitet.
    Runesson, K.
    Chalmers University of Technology.
    Sture, S.
    University of Colorado, Boulder.
    Yu, Y,
    Luleå tekniska universitet.
    Alawji, H.
    University of Colorado, Boulder.
    Characteristics and integration of undrained response of silty soils1989Inngår i: Numerical models in geomechanics: [the proceedings of the 3rd International Symposium on Numerical Models in Geomechanics held on 8 - 11 May 1989, Niagara Falls, Canada / [ed] S. Pietruszczak; Gyanendra Nath Pande, London: Elsevier, 1989, s. 195-203Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Constitutive behaviour of silt is discussed with emphasis on undrained response. Triaxial undrained tests performed on silt shows contractant behaviour at small strains but dilatant behaviour at higher strains, whereafter the soil fails. A constitutive model for silt based on elastoplacticity is proposed and numerically investigated

  • 255.
    Axelsson, Kennet
    et al.
    Luleå tekniska universitet.
    Rydén, C-G
    Luleå tekniska universitet.
    Experimental determination of pore pressure development in a thawing soil: contribution to the 9th International Conference on Port and Ocean Engineering under Artic Conditions - POAC 871987Rapport (Annet vitenskapelig)
  • 256.
    Axelsson, Kennet
    et al.
    Luleå tekniska universitet.
    Yu, Yao
    Luleå tekniska universitet.
    Johansson, L.
    Finite element analysis of an excavated slope1992Inngår i: Landslides: proceedings of the international symposium / 10-14 February 1992 / Christchurh / [ed] David H. Bell, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1992, Vol. 6, s. 295-300Konferansepaper (Fagfellevurdert)
  • 257.
    Axelsson, Kennet
    et al.
    Luleå tekniska universitet.
    Yu, Yao
    Luleå tekniska universitet.
    Runesson, Kenneth
    Chalmers University of Technology.
    Constitutive modelling of Swedish fine grained soils1991Inngår i: Deformation of soils and displacements of structures: X ECSMFE, Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1991, Vol. Vol. 1, s. 183-187Konferansepaper (Fagfellevurdert)
    Fulltekst (pdf)
    FULLTEXT01
  • 258.
    Axelsson, Kennet
    et al.
    Luleå tekniska universitet.
    Yu, Yao
    Luleå tekniska universitet.
    Runesson, Kenneth
    Chalmers University of Technology, Department of Structural Mechanics.
    Klisinski, M.
    Chalmers University of Technology, Department of Structural Mechanics.
    Determination of constitutive parameters for soils based on optimization1991Inngår i: Computer methods and advances in geomechanics: proceedings of the Seventh International Conference on Computer Methods and Advances in Geomechanics, Cairns, 6-10 May 1991 / [ed] G. Beer, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1991, s. 569-574Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Optimization-based methods for the determination of constitutive parameters of material models are evaluated. Rosenbrock's and Levenberg-Marquardt's algorithms are considered in particular. Based on experimental data for Swedish silt, two plasticity models are calibrated and their performances are compared

  • 259.
    Axelsson, Kenneth
    Luleå tekniska universitet.
    On distortional plastic hardening1978Rapport (Annet vitenskapelig)
  • 260.
    Baby, Sultana Nasrin
    et al.
    Royal Melbourne Institute of Technology, RMIT University, Melbourne, Australia.
    Arrowsmith, Colin
    Royal Melbourne Institute of Technology, RMIT University, Melbourne, Australia.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Application of GIS for Mapping Rainwater-Harvesting Potential: Case Study Wollert, Victoria2019Inngår i: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 11, nr 1, s. 14-21Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Water is a basic normal asset for supporting the condition of life. Accessible water assets are feeling the squeeze because of expanding demand. Soon wa- ter,  which  we  have  epended  upon  to  be  accessible  and  an  unconditional present of nature will turn into a rare roduct. Protection and conservation of water assets are desperately required. In many parts of Victoria, water supply to communities is limited. Rainwater harvesting systems can provide water ator near the point of demand. The systems can be owner and utility operated and  managed.  Rainwater  collected  using  existing  structures,  i.e.  rooftops, parking lots, playgrounds, parks, ponds, floodplains etc., has few negative en- vironmental impacts compared to other technologies for water resources de- velopment. Rainwater is relatively clean and the quality is usually acceptablefor many purposes with little or even no treatment. The physical and chemi- cal properties of rainwater are usually superior to sources of groundwater that may have been subjected to contamination. The present study was intended to measure the rooftop rainwater harvesting potential using GIS techniques. The GIS examination utilized in this investigation was basically an efficient assess- ment  of  rooftop  water  collecting  in  the  chose  Wollert  which  is  a  suburb  in Melbourne, Victoria. With the use of GIS it was conceivable to appraise the ag- gregate sum of water harvestable at the household level. It is very tedious work to assess the catchments available for rooftop rainwater harvesting. Here the roof surfaces are the catchments and GIS is employed to calculate the area of various  types  of  roofs  and  their  potential  for  planning  for  the  area  under study.  As  a  result  Eucalypt  Estate  Wollert  has  huge  potential  and  can  makeabove 179.11 litres water available per person per day throughout the year.

    Fulltekst (pdf)
    fulltext
  • 261.
    Baby, Sultana Nasrin
    et al.
    School of Mathematical and Geospatial Sciences, Royal Melbourne Institute of Technology, RMIT University, Melbourne, Australia.
    Arrowsmith, Colin
    School of Mathematical and Geospatial Sciences, Royal Melbourne Institute of Technology, RMIT University, Melbourne, Australia.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Abbas, Nahlah
    School of Engineering and Technology, Central Queensland University, Melbourne, Australia.
    Spatial Decision Support System for CoastalZone Management under a ChangingClimate in Victoria, Australia2018Inngår i: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 10, nr 10, s. 637-642, artikkel-id 87732Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The ultimate aim of using spatial  datasets and  spatial  data modelling is  fo- cused on enabling a sustainable environment by bringing the public policies into  practice.  The  consequence  will  be  sustainable  spatially  aware  strategic planning for  all  levels  of  Australian government.  Geographical  Information Systems (GIS) are the platform that can serve this aim provided that model, current process and spatial datasets are fit for purpose. To bring public policy into practice a broad range of knowledge from different disciplines is needed. Most decision making processes are pressured in terms of time and driving forces and also the process is beyond the knowledge of individuals in the var- ious  disciplines.  There  is  a  need  for  immediate  uptake  models  and  tools which are relevant to the target subject that will facilitate this decision making process. This paper focuses on realizing the utility in spatial data and spatial data handling in order to help climate change adaptation programs at local government level. Web-based mapping tools can assist planners prepare for the changing climate conditions in Bass Coast Shire Council. The GIS team has gathered data from various climate research organizations to understand projections of what different climate scenarios might look like over the next 100-year period. From this website demo it is hoped that the user will under- stand  how  the  tool  works,  background  information  on  different  GIS  plat- forms, access to interactive mapping, online geospatial analysis tools, videos, open source resource, sea level tools, modelling, 3D visualization and direct download access to various planning and natural resource data sets relating to environment  management.  Some  results  from  our  elevation  data  analysesthrough these Web map visualization tools are provided.

    Fulltekst (pdf)
    fulltext
  • 262.
    Baby, Sultana Nasrin
    et al.
    Royal Melbourne Institute of Technology, RMIT University, Melbourne, Australia.
    Wojcik, Bozena
    Senior GIS Officer at City of Whittlesea, Melbourne, Australia.
    Murone, Adrian
    Arborist and Aspiring Urban Forester, Melbourne, Australia.
    Martin-Chew, Linda
    Consultant/Director Plan-It Rural PL and Senior Strategic Policy Planner at City of Whittlesea, Melbourne, Australia.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Developing an Automated City of Whittlesea Urban Tree Canopy Inventory Using Airborne LiDAR and Aerial Imagery2019Inngår i: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 11, nr 12, s. 828-840Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The City of Whittlesea is in Melbourne’s north and is one of the largest municipalities in metropolitan Melbourne. The council GIS team using current aerial photos from 2017 and LiDAR (“LiDAR” stands for Light Detection and Ranging) point clouds 2009 products to identify trends in urban tree canopy cover in the established suburbs of the municipality between 2009 and 2017. The tree canopy coverage was calculated for residential properties, road reservations, public land and park sites within urban parts of Bundoora, Epping, Lalor, Mill Park, Thomastown, and South Morang. From the total project area of approximately 3499 hectares a test site was selected based on an extension of one of the LIDAR data tiles (e325n5828). This project investigates only 6 meters and higher tree canopy cover within the project area. The objectives of the project were to establish a methodology to calculate the urban tree canopy coverage from LiDAR 2009 data, that can be replicated in future calculations. The calculated urban tree canopy coverage from LiDAR 2009 data is 9%, compared to 8% coverage in 2017, based on aerial photography. This estimate was compared to similar Local Governance Areas that range from 12% to 40%. A key to planning and managing urban tree canopy is first to understand the quantity, quality, tree density and distribution of the resource across the landscape. Tree inventories and urban tree canopy analyses comprise an assortment of tools, technologies, and procedures that help us understand the structure and function of our urban tree canopy. The data and information gleaned from urban tree canopy assessments enable resource professionals and policymakers to make informed decisions about ordinances, housing diversity strategy, and budgeting, future tree planting programs and reduce urban heat islands.

    Fulltekst (pdf)
    fulltext
  • 263.
    Bapeer, Galawezh Bakr
    et al.
    Department of Geotechnical Engineering, Faculty of Engineering, Koya University, Koya, Kurdistan Region, Iraq.
    Muhammad, Rozhgar Kamal
    Directorate of Slemani Construction Laboratory, Sulaimaniya, Kurdistan Region, Iraq.
    Nadr, Kazhan Akram
    Directorate of Slemani Construction Laboratory, Sulaimaniya, Kurdistan Region, Iraq.
    Khodakarami, Loghman
    Department of Petroleum Engineering, Faculty of Engineering, Koya University, Koya, Kurdistan Region, Iraq.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Geotechnical Properties of Soil in Ranya and Arbat Area, Sulaimaniya, Kurdistan Region, Iraq2020Inngår i: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 10, nr 5, s. 35-48Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study deals with the determination of some geotechnical properties of soil in Ranya district and Arbat sub-district area. These two areas are located in Sulaymaniya Governorate, Kurdistan region of Iraq. The soil in nature is changing from one place to another. This is because of the mineral composition of rocks and climate change, so, studying the properties of soil is important for various purposes especially for engineering structures. In this paper, some geotechnical soil were studied, like particle size distribution, specific gravity and Atterberg limits. The study of particle size distribution indicated that the soil comprises mostly of silt and sand with some clay. This means that the soil consists of coarse and fine mixture. The Atterberg limits results are indicating that both areas are characterized by low to medium plasticity index. Specific gravity test results are indicating that the soil in both areas is free from iron and mica minerals. A good matching of the geotechnical soil properties between Ranya and Arbat area is indicated. 

    Fulltekst (pdf)
    fulltext
  • 264.
    Barnes, David L.
    et al.
    University of Alaska, Fairbanks.
    Cosden, Elizabeth
    Fairbanks Environmental Service.
    Johnson, Bryan
    Fairbanks Environmental Service.
    Johnson, Karol
    Fairbanks Environmental Service.
    Stjärnström, Stina
    Luleå tekniska universitet.
    Johansson, Karin
    Luleå tekniska universitet.
    Filler, Dennis M.
    Shannon and Wilson, Inc..
    Operation of soil vapor extraction in cold climates2002Inngår i: Cold regions engineering: cold regions impacts on transportation and infrastructure : proceedings of the eleventh international conference, May 20-22, 2002, Anchorage, Alaska / [ed] Kelly S. Merrill, New York: American Society of Civil Engineers (ASCE), 2002, s. 956-967Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Soil Vapor Extraction has proven to be a viable method for reducing the mass of volatile compounds from soils that have been impacted by contamination. The theory, design and use of SVE systems have been fairly well documented, however the use of SVE systems in cold environments such as Alaska has not been adequately investigated to date. This paper examines the use of SVE systems in cold environments. The affect of low soil temperatures on volatile compound removal by SVE is discussed. Methods used to overcome the impact low temperatures have on the operation and effectiveness of SVE systems are examined in detail. Possible low cost strategies such as barometric pumping during winter months are presented as solutions to reducing SVE operating costs in cold regions

  • 265.
    Benckert, A.
    Luleå tekniska universitet.
    Gruvdammar: Dammsäkerhet och efterbehandling2004Inngår i: Proceedings: NGM 2004. XIV Nordic Geotechnical Meeting, Linköping: Svenska geotekniska föreningen , 2004, s. G 51-Konferansepaper (Annet vitenskapelig)
  • 266.
    Bergliv, Elin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Edeskär, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Laboratory study on two-dimensional image analysis as a tool to evaluate degradation of granular fill materials2016Inngår i: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM: Reykjavik, Iceland 25th – 28th of May 2016, 2016, s. 461-470Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The shape of granular materials is known to affect strength and stiffness properties of soil and fills. Settlements in coarse fills are often explained by rearrangement within the soil skeleton induced by crushing and rounding of the individual aggregates in the intergranular contact points. These processes are not well investigated since it is difficult to measure changes at an aggregatelevel.Currently few attempts have been made to effectively measure and classify shape of granular soil and fill materials. One of the more promising methodologies is digital image analysis. Even if there are some studies on both two and three dimensional analyses on shape of aggregates, no study has focused on identifying shape changes as function of degradation effects of the fill materials.In this study degradation of ballast material has been studied in standardized micro Deval and Los Angeles tests and analysed by two dimensional image analysis and statistical methods. The results showed it was possible to statistically separate the shape and size of the materials before and after the degradation tests. To identify this difference it is essential to use more than one variable each for size and shape.The conclusion of the study is that two-dimensional image analysis can be used as a tool to measure and quantify shape changes on an aggregate level in order to measure degradation. If further developed, the technique can be useful to study deformation processes, e.g. crushing and rounding of aggregates, in coarse fill materials.

    Fulltekst (pdf)
    fulltext
  • 267.
    Berglund, Andreas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Prognos av vägars bärförmåga vid tjällossningen: Användning av "Minnesotamodellen" på en teststräcka i Sverige2010Rapport (Annet vitenskapelig)
    Abstract [en]

    The global trend towards a warmer climate and temperatures near or just above 0 °C during winter months, will most likely be more common in future. One of the consequences of this climate change could, in a worst-case scenario, be freezing and thawing over a significant part of the winter with corresponding road bearing capacity problems. Bearing capacity problems may lead to increased costs to society when heavy traffic is forced to change route or carry less weight. In addition, road maintenance costs will increase. According to pulp industry calculations, this industry sector will face additional costs in the range of 510-590 Million SEK every year due to road bearing capacity problems. In addition to this, the costs related to the rapidly growing bio fuel industry will be added. If a reliable forecast of load-bearing capacity problems and potential load restrictions on roads can be found, it would be cost effective for road administration and society. This research report is a part of a work to find methods to forecast bearing capacity problems on roads. The report gives an idea of the possibility to use the temperature based model used in Minnesota, USA in Sweden. The evaluation is done by comparing falling weight deflectometer (FWD) test results with the results from the temperature based forecast model. Temperatures and FWD data were collected in 1997 on a road approximately 7 km outside Luleå, Sweden. The road structure was from the surface: 0,10 m asphalt, 0,40 m sandy gravel/gravely clayey sand and 3,0 m silty clay overlaying a silty moraine. In the report the FWD concept, as well as the FWD parameters of importance are described. How the temperature data was collected is described. The temperatures were collected at a depth of 0,20 m and 0,12 m below the asphalt layer respectively. FWD data was normalised to a force of 50kN. The radius of the segmented falling plate was 0,12 m and all calculations were carried out in accordance with Swedish guidelines. Based upon the FWD tests, the following parameters were evaluated: i/load carrying index, ii/surface modulus, iii/subgrade modulus and iv/"AREA-parameter". A daily average air temperature was determined based upon the detailed measured temperatures. A comparison was done with an average value calculated solely on the recorded maximum and minimum temperatures. It is shown that the two methods gave similar results when used in the forecast model. A short description of the temperature based forecast model is presented as well as an example of how to use it. The needed reference temperature was in the field test evaluated to -0,65 °C and the thaw-degree day limit before the road starts to thaw was determined to 22,2 °C-days. The evaluated FWD parameters show bearing capacity loss at slightly different days. Load carrying index shows a loss of bearing capacity after March 14. As expected the surface modulus is strongly influenced by the air temperature and shows low values on March 10, April 1. After April 11 it decreases significantly. The subgrade modulus shows less stiffness after March 26 and is not as affected by changing air temperatures as the surface modulus. The AREA parameter is also affected by the oscillations in air temperature, much like the surface modulus. It shows low values on March 10 and April 1. After April 11 it decreases significantly towards the lowest values registered in the study. The temperature based forecast model shows that the limit for the accumulated thaw index is reached on March 10 and on April 22-23. The results from the forecast model based upon the daily average temperatures and based upon daily maximum and minimum temperatures only, shows almost the same dates for bearing capacity reductions. Thus, the more simple method with maximum and minimum temperature values seems to give enough accuracy. When comparing the FWD results: AREA-parameter and subgrade modulus with results from the Minnesota model, the subgrade modulus seems to have the greatest agreement with the forecast model. However, they both seem to show the overall development of low bearing capacity during thaw. The overall conclusion about the temperature based forecast model is that it seems to give fairly good results and work well. It will work better if it can be further calibrated but it has some flaws if the temperature seesaws around 0 °C. The forecast model should, despite this, be able to assist road holders in Sweden as a planning tool, when dealing with bearing capacity problems during thaw.

    Fulltekst (pdf)
    FULLTEXT01
  • 268.
    Berglund, Andreas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Prognos av vägars bärförmåga vid tjällossningen: användning av temperatur som nyckeltal2010Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The global trend towards a warmer climate and temperatures near or just above 0 °C during winter months, will most likely be more common in future. One of the consequences of this climate change could, in a worst-case scenario, be freezing and thawing over a significant part of the winter with corresponding road bearing capacity problems. Bearing capacity problems may lead to increased costs to society when heavy traffic is forced to change route or carry less weight. In addition, road maintenance costs will increase. According to pulp industry calculations, this industry sector will face additional costs in the range of 510-590 Million SEK every year due to road bearing capacity problems. In addition to this, the costs related to the rapidly growing bio fuel industry will be added. If a reliable forecast of load-bearing capacity problems and potential load restrictions on roads can be found, it would be cost effective for road administration and society. This text presents the content of the licentiate work is presented and in what report more information could be found. One aspect of frost damage on roads that is highlighted in the thesis is decision making when conducting a road inventory. In a study conducted within the licentiate work it was shown that the results from different actors performing frost inventory on the same road stretch can vary a lot. There should be efforts made to reduce the individual dependence when performing a road inventory. The main part of the licentiate work deals with a model for the prediction of bearing capacity problems on roads. The work gives an idea of the possibility to use the temperature based model used in Minnesota, USA in Sweden. The evaluation is done by comparing falling weight deflectometer (FWD) test results with the results from the temperature based forecast model. When comparing the FWD results: AREA-parameter and subgrade modulus with results from the Minnesota model, the subgrade modulus seems to have the greatest agreement with the forecast model. However, they both seem to show the overall development of low bearing capacity during thaw. The overall conclusion about the temperature based forecast model is that it seems to give fairly good results and work well. It will work better if it can be further calibrated but it has some flaws if the temperature seesaws around 0 °C. The forecast model should, despite this, be able to assist road holders in Sweden as a planning tool, when dealing with bearing capacity problems during thaw.

    Fulltekst (pdf)
    FULLTEXT01
  • 269.
    Berglund, Andreas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Studie av modell för prognos av vägars bärförmåga vid tjällossningen: "Minnesotamodellen"2010Rapport (Annet vitenskapelig)
    Abstract [en]

    Many roads are affected negatively by thaw with loss of bearing capacity as a consequence. Sometime load restriction policies must be applied on these roads. To be able to communicate potential bearing capacity problems in time with the road users, a prognosis model is needed. Such a model is described in this report. The model is described based upon a report made at Washington state department of transportation, WSDOT. WSDOT had carried out thermal analysis by FEM on four different road sections. The four sections are presented and the thermal properties of the road materials are given. A most likely misprint in the original report is commented upon and a table with correct SI-units is presented. The results coming from the thermal analysis is presented. Thawing in the tested road sections starts when the daily average air temperature is -1,7 °C to -1,1 °C. Limits for a should and a must level of accumulated thawing index is presented as 25 °F-days and 50 °F-days. When the level is reached load restrictions should apply. In the Minnesota Department of Transportation, Mn/DOT, version of the forecast model only one limit is used. The length of the load restrictions are based on the complete thaw of the road construction. Two equations for calculating the length of restrictions based on FI and TI are presented. Comparisons between the results of the forecast model and frost depth meters have been carried out and showed acceptable results. The forecast model is working better when fine grained materials is present than with coarse grained materials. The model was stated usable but in need of in-situ calibration. The model has been altered in the Mn/DOT version by letting the reference temperature vary during spring. This is said to be a way of taking the increasing intensity of the net heat flux and angle of the sun into consideration. It can also be seen as an easy way of calibrating the forecast model. The three day weather forecast is used to determine when the limit value for accumulated thaw index is reached. This gives the forecast model a three days forecast on bearing capacity problems. Within Mn/DOT maximum 8 weeks duration for load restrictions are used. Research showing that load restrictions are not socioeconomic defendable and that it is more economic to have the road repaired when it gets damaged is presented. Other works say that there is a value in load restrictions. Socioeconomic calculations may contain assumptions and whether or not they are correct is not discussed in this report. Before the forecast model could be implemented in Sweden there is a need for testing. Air and ground temperature data needs to be collected and analysed according to this report. The temperature data will give reference temperature and limit value to use when evaluating thaw index. The test results from the forecast model should be compared with for example falling weight deflection data from the same location to answer the question whether the agreement is good or not. The forecast model is straight forward and simple. Some questions about reliability need future testing before a recommendation whether or not it is suitable to be used in Sweden.

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  • 270.
    Berglund, Andreas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Tjäle - en litteraturstudie med särskilt fokus på tjällossning2009Rapport (Annet vitenskapelig)
    Abstract [sv]

    Denna forskningsrapport är en litteraturgenomgång av en del av allt som finns skrivet om tjälprocessen och de problem tjälen skapar. Rapportens övergripande fokus ligger till en början på att ge en överblick över tjälprocessen och presentera grunderna i denna. Efter hand glider fokus över mot tjällossningen och de problem som förknippas med tjällossning. En allmän presentation av frusen jord, jord med en temperatur under 0°C, och en överblick över tjälforskningens historia från år 1765 och Beskow till mer nutida forskningsrön presenteras allra först i rapporten. Jordens termiska egenskaper är essentiell för tjälprocessen och beskrivs med hjälp av begrepp såsom termisk konduktivitet (värmeledningstalet λ), värmekapacitet (c), termisk diffusivitet (α) och latent värme (L). Temperaturprofilen beskrivs i termer av geotermisk gradient, whiplashkurva och aktivt område. Med aktivt område menas det område som tinar respektive fryser i permafrost och säsongstjäle.Tjälnedträngningen som orsakas av negativa varaktiga temperaturer vid markytan beskrivs i rapporten. Negativa yttemperaturer skapar ett värmeflöde från marken. Marken kyls ned i och med värmeavgången och bildandet av islinser i jorden inleds. Vattentransporten till tjälfronten som påverkar bildandet av islinser är komplex och fenomenet är än inte helt utrett. De två huvudspåren kapillärt sug och att vattentransporten beror av fysisk-kemiska egenskaper hos jorden presenteras. Vattentransporten till islinsen sker via en vattenfilm av ofruset vatten, den ofrusna vattenkvoten betecknas wu. Den hydrauliska konduktiviteten minskar med negativa temperaturer på grund av att vattentransporten sker i den ofrusna delen av vattnet, och wu minskar med negativa temperaturer. Beräkning av tjäldjup presenteras genom en härledning av Stefans formel, en presentation av Stefans modifierade formel och en förklaring av köldmängdsbegreppet. Modifierad Stefans formel som tar hänsyn till jordens värmekapacitet presenteras också. Förutom lufttemperaturen bestäms tjäldjupet i en jordprofil främst av jordmaterialets värmetekniska egenskaper. Tjällyftning och bestämning av tjällyftets storlek med segregation potential theory behandlas. Fenomenet vid tjällossning beskrivs samt problemen vid tjällossningen presenteras. För bärighetsproblem vid tjällossningen är dräneringen av vägkonstruktionen kritisk eftersom de ökade portrycken innebär minskade effektivspänningar och minskad skjuvhållfasthet. Dräneringsförmågan inverkar främst om urtjälningshastigheten är hög, mycket is övergår till vatten på kort tid. Sättningar på grund av tjällossning styrs främst av mängden is i jorden. Tjälfarlighetsklassificeringssystemen använda i Sverige, Norge, Finland och USA beskrivs och en jämförelse mellan dessa görs. Två jordar klassificeras utifrån kornfördelningskurvorna, för en grusig sand ger ländernas system samma svar, ej tjälfarlig. Även för den andra jorden, en sandig siltig lermorän klassificeras jorden som tjälfarlig, dock i olika grad. Hur vägar påverkas av tjälnedtränging (höjd hållfasthet, lägre hydraulisk konduktivitet), tjällyftning och tjällossning (bärighetsminskning, tjälskott med mera) beskrivs. Vägverkets system för väderdata VViS presenteras. Med hjälp av väderdata kan modeller för införandet av lastrestriktioner skapas. CTI-fordon har fördelar vid bärighetsnedsättningar. Sverige använder enbart visuella observationer vid införandet av lastrestriktioner på grund av bärighetsnedsättningar vid tjällossning. Flera andra länder och stater i USA använder mer sofistikerade metoder. I Minnesota används väderdata i form av frys- (FI) och töindex (TI) tillsammans med en referenstemperatur för att förutse när lastrestriktioner bör införas. Kanske är "Minnesotamodellen" något för Sverige.

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  • 271.
    Berglund, Andreas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Tjälinventeringsprojektet: en jämförande studie av tjälinventeringar gjorda av olika aktörer2010Rapport (Annet vitenskapelig)
    Abstract [en]

    Roads are affected by frost. For maintenance and action planning of these roads, a well performed inventory is a necessary base. It will also be a base for priority of different objects for repair and maintenance. Therefore, it is very important to have a similar ground for the judgment. This can be difficult to achieve as different companies and persons are enrolled different years due to type of contract used, capacity, experience, knowledge etc. In a pre-study great differences were found when comparing two inventories done on the same road in year 2008 and 2009. The question was then raised, if the provided information on how to perform an inventory was good enough in order to carry out a high quality work. Another question raised, was if the differences really are that obvious between different persons performing the inventory.The method used for the study was to have four actors to carry out an inventory each on the same road, at the same time, and then compare the obtained results. The actors were "Konsult A" and B, Swedish Transport Association (TV) and persons from Luleå University of Technology (LTU). Ranked in order of practical experience the most experienced was Konsult B, then Konsult A, TV and LTU. The road studied was AC805 Lidbacken to Femvägaskälet. It is situated outside Skellefteå in the county of Västerbotten in the north part of Sweden. The total length of the studied road was about 15 km and it has an ADT of 576. Four sections, which represented the road as a whole and also showed the main differences and similarities, were closer analyzed. One section focused on an overview, one on cracks and two sections focused on bumps and roughness. In the report, the results from the four inventories are presented graphically in order to give the reader an overview and a chance to comparison. The results show that there are both great differences and similarities between the four inventories. The two most experienced, Konsult A and Konsult B had about the same percentage of their total crack length in class 2 (66 respectively 60%) and class 3 (~30%). The total amount of inventoried crack length differs however. Konsult A have in total 7355m and Konsult B 9157m, which means that Konsult A only reports approximately 80% of the length reported by Konsult B. TV had 18% class 2 and 82% class 3 cracks with a total length of cracks being 3246m, while LTU had 38% class 2 and 24% class 3 cracks. In this case the total crack length was reported to be 11029m. This means, that the total length of reported cracks varies between 3246 m to 11029 m, corresponding to approx. 21% and 74% of the total road length.The most experienced (Konsult B) and the least experienced performer (LTU) show most similarities in the overall road condition assessment and placement of damages. It is mentally exhausting to perform a road inventory by hand without small amount of technical support. It is shown in the report that the resolution seems to decrease after some time of work. As a consequence, many cracks in class 1 are registered in the beginning of the studied road stretch, while in the end cracks are more registered as long single cracks. After some time of work more cracks are registered as coherent cracks while they in fact are single cracks. It should therefore be considered if technical supporting systems, like e.g. GPS and computers with well developed software, should be more used in order to increase efficiency and quality of the final work. This should also reduce the impact of subjective decisions.One observation done in the study is that different persons might have different views of the purpose of the road inventory. One view is to perform just a road inventory, without any specific purpose, more than to get a view of the quality of the road. Another point of view is to do an inventory with the focus of what type of actions are to be carried out in future in mind. Depending on the focus, the results seem to differ. In this study, it seems like LTU, Konsult A and Konsult B have performed the inventory in the first way, while TV seems to have carried the inventory out with future actions in mind. This conclusion is based upon the observation that TV did not note any damages in class 1 throughout the whole road stretch, while the other did. By analysing the inventory results, it was found that errors in the distance measurements were present. It is therefore proposed that the customer should consider GPS-length measurements to eliminate this source of error. Inventory done with the base of digital photos will minimize some of the length measurement problems if the photos are taken by a camera connected to a GPS. However, inventory done by using digital photos only have several disadvantages in comparison with ordinary field inventory. The major drawback of this methodology is the difficulty to discover small damages and roughness. It is difficult to classify roughness. The roughness effect on driving experience is very much dependent on the speed of the inventory vehicle. Based on this study the speed of the inventory vehicle needs to be considered when doing a roughness inventory. Roughness inventory should be done at the roads intended speed to ensure that the roughness impact on driving comfort is correctly experienced and registered. One way to enhance the quality of road inventory could be to develop a clear and easy to understand description of method. It should be emphasised that experience is a key component when doing road a inventory, but an increased use of technical support systems can reduce the scatter in the assessment.

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  • 272.
    Berglund, Andreas
    et al.
    LTU.
    Edeskär, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Comparison between temperature based thaw weakening prediction model and field observation methods2011Inngår i: Proceedings of the 21st International Conference on Port and Ocean Engineering under Arctic Conditions, Montreal, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Structures like roads and port yards located in cold climate are affected by freezing and thawing every year. The global trend of a warmer climate and temperatures around 0°C for longer periods of time will change the freezing/thawing behaviour in many locations. The tendency will changeto have several freezing /thawing cycles in a given location every year. The bearing capacity of low volume roads and simple port yards will be affected by a prolonged thawing period with lower bearing capacity as a consequence. Bearing capacity problems can lead to increased costs for traffic as well as increased maintenance costs. Due to very high costs for destroyed structuresduring thaw, a lot can be gained if bearing capacity problems at a given site can be forecasted well in advance in order not to destroy the structure. Such a method should preferably be based upon simple measurements like air temperatures to make it easy to use also in remote areas. In the described temperature based model air and ground temperatures are used to develop anaccumulated thaw index and corresponding limits. When the thaw index limit is reached, the construction at the evaluated depth thaws, leading to increased pore water pressure and reduction of strength and bearing capacity. This paper presents a study of the application of the model at low volume roads in Sweden. Bearing capacity at the road was evaluated from field tests by falling weight deflectometer (FWD) test carried out 24 times during the thawing season i.e.March 4 through June 9. Predictions made by the model were compared with the subgrade module evaluated from the FWD series. The results show that the model might be possible to use in Sweden and elsewhere if minor adjustments are carried out.

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  • 273.
    Bergman, Stina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Livscykelanalys för grundläggning av byggnader: Användningen idag och hur metoden kan tillämpas i praktiken2018Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Byggsektorn står idag för en stor andel av växthusgasutsläppen vid produktion av byggmaterial ochanvändningen av byggmaskiner under byggproduktionsskedet. Det nationella målet är att Sverige år 2045ska vara koldioxidneutralt och utifrån detta mål har Fossilfritt Sverige, tillsammans med ett stort antalaktörer från bygg- och anläggningssektorn, tagit fram en färdplan för hur branschen ska bli klimatneutralt.Grundläggning står för en betydande del av den totala byggnadens klimatpåverkan och för att nå måletmed ett klimatneutralt Sverige år 2045 är det viktigt att discipliner inom grundläggning börja arbeta medutveckling och optimering av grundläggningskonstruktioner för att minska klimatpåverkan.

    I detta examensarbete har en intervjustudie utförts för att kartlägga vilka aspekter som styr valet avgrundläggningsmetod idag utifrån entreprenören och konsultens perspektiv samt för att kartlägga hurdessa aktörer använder livscykelanalys inom grundläggning av byggnader. En fallstudie har utförts för attundersöka hur livscykelanalys kan användas för att beräkna och jämföra klimatpåverkan samtprimärenergianvändningen från grundläggningsmetoder för byggnader genom att prova och utvärderatvå digitala LCA-verktyg.

    En litteraturstudie har genomförts för att skapa kunskap inom grundläggning och för att skapa förståelseom klimatpåverkan från byggsektorn samt vilka klimatkrav som finns. Litteraturstudien har legat till grundför valet av de två digitala LCA-verktyg som används i fallstudien samt har används för att ta fram enintervjuguide. Intervjuer har genomförts med aktörer från konsult- och entreprenadföretag som harvarierande erfarenheter och kunskaper inom livscykelanalys för grundläggning. Vidare har en fallstudiegenomförts där en jämförande livscykelanalys utförs mellan två grundläggningsmetoder, platta med pålaroch platta med lastkompensation, genom att använda två digitala LCA-verktyg, Klimatkalkyl 6.0 och BM1.0. LCA-studien utgår från verktygens avgränsningar och beaktar endast första delen av livscykeln,byggskedet (modul A1-A5) där Klimatkalkyl 6.0 beräknar klimatpåverkan och primärenergianvändningenoch BM 1.0 beräknar endast klimatpåverkan.

    Resultatet från intervjuerna visar att grundläggningsmetoder ofta väljs utifrån den ekonomiska aspektenmen att personlig erfarenhet, geografisk och historisk tradition även påverkar. Respondenterna anser attklimat- och miljökrav som förekommer i projekt ofta är otydliga och svåra att förstå. Intervjustudienindikerar att användningen av livscykelanalys är begränsad. Enligt respondenterna skulle användningenöka om man utvecklade kompetens hos konsulter och entreprenörer, förenklade LCA-modellen menframförallt om deras beställare tydliggjorde kravställningarna.

    I fallstudien visar de två verktygen på olika klimatpåverkan för respektive grundläggningsmetod och olikaskillnader vid jämförandet av de två grundläggningsmetoderna. Båda verktygen visar att grundläggningmed platta med pålar ger en lägre klimatpåverkan än platta med lastkompensation under byggskedetmed givna förutsättningar. Skillnaden mellan grundläggningsmetoderna är 2 eller 5 tonkoldioxidekvivalenter beroende på vilket verktyg man använder, vilket motsvarar cirka 13 respektive 23procent i skillnad. Båda verktygen visar även att betong, cellplast och stål är de byggnadskomponentersom bär den största andelen av den totala klimatpåverkan för respektive grundläggningsmetod.

    Ingen av verktygen Klimatkalkyl 6.0 och BM 1.0 är utvecklade för grundläggning av byggnader och i bådaverktygen saknas det byggnadsdelar som ingår i grundläggningsmetoderna, som studeras i fallstudien.Resultatredovisningen från respektive verktyg är även svårtolkade och bör utvecklas. Trots detta så ansesdet att båda verktygen kan användas som hjälpmedel för att beräkna och visa vilketgrundläggningsalternativ som ger minst klimatpåverkan.

    Då den ekonomiska faktorn idag är styrande för valet av grundläggningsmetod kan denna parameteranvändas som styrmedel för att öka arbetet med klimatanpassade lösningar. Förslag på fortsatta studierär att ta fram en relation mellan kostnader och klimatpåverkan för grundläggningsmetoder samt attundersöka hur man kan implementera livscykelanalys på projektörsnivå för att öka dess användning.

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  • 274.
    Bernander, Stig
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Analys av progressiva skred utförda av Con-Geo: Bilaga till Skredet i Småröd, Rapport 1 - Skredorsak2007Rapport (Annet vitenskapelig)
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  • 275.
    Bernander, Stig
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Angående Statens Geotekniska Instituts Rapport Nr 18: "Un élefphant naît une souris"1983Inngår i: Geotekniknytt (och lite gammalt), Vol. 1983, nr 1, s. 1-17Artikkel i tidsskrift (Annet vitenskapelig)
  • 276.
    Bernander, Stig
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Down-hill progressive landslides in soft clays: Triggering disturbance agents, Slide Propagation over horizontal or gently sloping ground, Sensitivity related to geometry2008Rapport (Annet vitenskapelig)
    Abstract [en]

    A numerical model is presented and discussed for down-hill progressive landslides in soft clays. A simple-to-use spread sheet is given and used in order to illustrate the influence of the sensitivity of the clay and the geometry of the ground. The model is also used to discuss the agents and the mechanisms that formed the large landslide in Surte at the Göta River in 1950.

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  • 277.
    Bernander, Stig
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Lerors hållfasthet och deformationsegenskaper i konstruktioner där leran icke ugör den enda stabiliserande komponenenten1975Inngår i: NGM 75: Nordisk Geoteknikermöde i Köbenhavn 22-24.5.1975, Köbenhavn: Polyteknisk Boghandel og Forlag, 1975, s. 155-172Konferansepaper (Fagfellevurdert)
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  • 278.
    Bernander, Stig
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Progressive landslides in long natural slopes: Formation, potential extension and configuration of finished slides in strain-softening soils2011Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    After the large landslide in Tuve (Gothenburg, 1977), the author began developing a finite difference model for slope stability analysis taking the deformation-softening of soft sensitive clays into consideration. In the model, the mean down-slope deformation in each element caused by normal forces is maintained compatible with the deformation generated by shear stresses. He developed software for the model and presented it at international soil mechanics conferences during the 1980-ies. In 2000 he summarized his findings in a Licentiate thesis. An easy-to-use spread-sheet has also been developed. In this thesis the author conveys his experiences of slide modeling focusing on the nature of triggering agents and the different phases that a slope may undergo before its stability becomes truly critical.

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  • 279.
    Bernander, Stig
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Progressive landslides in long natural slopes: potential extension and configuration of finished slides in strain-softening soils2000Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    A finite difference method is presented for progressive slides in long natural slopes. The method is based on a strain softening material model. A detailed worked out example is given as well as examples using a spread sheet PC program and a PC program for Windows. Several Scandinavian slides are analysed and discussed as case studies e g Tuve (1977), Surte (1951), Bekkelaget (1953), Rollsbo (1967), Rävekärr (1971), Tre-styckevattnet (1990) and Svärtaån (1938). The nature of down-slope progressive failures in natural slopes is described and the applicability of ideal-plastic failure analysis is questioned. Principles and procedures for investigation potential landslides are presented. A short historical background to the landslide problem is given in an introductory chapter.

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  • 280.
    Bernander, Stig
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Relationship between the appearence of a finished landslide and the mechanisms acting during the slide1984Inngår i: NGM-84, Nordiskt Geoteknikermöte 1984 i Linköping, Linköping: Statens geotekniska institut (SGI) , 1984, s. 409-416Konferansepaper (Fagfellevurdert)
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  • 281.
    Bernander, Stig
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Dury, Robin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Laue, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Progressive Landslide Analysis in Canadian Glacial Silty Clay in Churchill River2017Inngår i: / [ed] Vikas Thakur, Jean-Sébastien L’Heureux, Ariane Locat, 2017, s. 1-Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The poster presents the risks for a progressive landslide in a natural dam. The stability will be critical when the water level is raised after the building of a hydro power plant, Bernander (2016), Dury (2017). The analysis is based on a finite difference method developed by Stig Bernander (2011), Bernander et al.(2016)

     

    The following issues will be discussed:  

    - Material properties

    - Risk for liquefaction

    - Three possible failure surfaces: one horizontal, one inclined and one curved

    - Failure riska for different material propeties

    - The need to check the real properties of the soil

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  • 282.
    Bernander, Stig
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Stability of the North Spur at Muskrat Falls2019Inngår i: Muskrat Falls Symposium: 28-29 September 2018, Memorial University. St. John’s, NL, Canada / [ed] Stephen Crocker, St. John's, NL, Canada, 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper presents the geotechnical background to one of the stability problems regarding the North Spur dam wall: This land was formed in the regression of the sea during and after the last ice age with deposits of multiple layers of silty sands and silty sandy clays that formed the valleys and plains that are now above sea level. Some of these layers, deposited thousands of years ago in post-glacial times, are vulnerable to liquefaction when they are disturbed. These conditions have in the past repeatedly caused slides along the banks of the Churchill river.

    In the current paper, a specific type of possible progressive failure – the most dangerous one in respect of the safety of the North Spur – is discussed. This type of landslide development may be caused by the rising water pressure, when - or after - the dam is impounded. As will be explained, such a slide could force part of the North Spur ridge to slide along a failure surface sloping East-wards into the deep river whirlpool downstream of Muskrat Falls. 

    In the following, we provide a brief overview of the geotechnical background behind our concerns, also discussing methods of mitigating the risk of the kind of slope failure in question. Hence, we propose measures such as compacting the soil by piling or by methods of grouting and drainage. We also suggest the need for an expert Advisory Panel to look further into the long-term safety of the North Spur.

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  • 283.
    Bernander, Stig
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Gustås, Hans
    Skanska.
    Olofsson, Jan
    Skanska.
    Improved model for progressive failure analysis of slope stability1989Inngår i: Proceedings of the twelfth International Conference on Soil Mechanics and Foundation Engineering, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1989, Vol. 21/3, s. 1539-1542Konferansepaper (Fagfellevurdert)
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  • 284.
    Bernander, Stig
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Gustås, Hasse
    Skanska.
    Consideration of in sity stresses in clay slopes with special reference to progressive failure analysis1984Inngår i: Canadian case histories: landslides: Preprint volume for the 37. Canadian Geotechnical Conference organized jointly with the 4. International Symposium on Landslides, Totonto: Univ. Toronto Press , 1984Konferansepaper (Fagfellevurdert)
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  • 285.
    Bernander, Stig
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Gustås, Hasse
    Skanska.
    Dynamisk studie av ett progressivt brott i en naturlig slänt1984Inngår i: NGM-84, Linköping: Statens geotekniska institut (SGI) , 1984, s. 431-442Konferansepaper (Fagfellevurdert)
    Fulltekst (pdf)
    FULLTEXT01
  • 286.
    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.

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  • 287.
    Bernander, Stig
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Ingvar
    Skanska.
    On Formation of Progressive Failures in Slopes1981Inngår i: Proceedings of the Tenth International Conference on Soil Mechanics and Foundation Engineering, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1981, Vol. 3, s. 357-362Konferansepaper (Fagfellevurdert)
    Fulltekst (pdf)
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  • 288.
    Bernander, Stig
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Svensk, Ingvar
    Skanska.
    On the Brittleness of Soft Clays and its Effects on Slope stability1982Inngår i: Väg- och Vattenbyggaren, ISSN 0042-2177, nr 7-8Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
    Fulltekst (pdf)
    FULLTEXT01
  • 289.
    Bernander, Stig
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Svensk, Ingvar
    Skanska.
    Holmberg, Gunnar
    Skanska.
    Bernander, Jarl
    Skanska.
    Isacsson, K
    Skanska.
    Shear strength and deformation properties of clays in direct shear tests at high strain rates1985Inngår i: Proceedings of the eleventh International Conference on Soil Mechanics and Foundation Engineering, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1985, Vol. 2/B/5, s. 987-990Konferansepaper (Fagfellevurdert)
    Fulltekst (pdf)
    FULLTEXT01
  • 290.
    Beyaztas, Ufuk
    et al.
    Department of Statistics, Bartin University, Bartin, Turkey.
    Salih, Sinan Q.
    Institute of Research and Development, Duy Tan University, Da Nang, Vietnam.
    Chau, Kwok-Wing
    Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Yaseen, Zaher
    Sustainable Developments in Civil Engineering Research Group, Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
    Construction of functional data analysis modeling strategy for global solar radiation prediction: application of cross-station paradigm2019Inngår i: Engineering Applications of Computational Fluid Mechanics, ISSN 1994-2060, E-ISSN 1997-003X, Vol. 13, nr 1, s. 1165-1181Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To support initiatives for global emissions targets set by the United Nations Framework Convention on climate change, sustainable extraction of usable power from freely-available global solar radia- tion as a renewable energy resource requires accurate estimation and forecasting models for solar energy. Understanding the Global Solar Radiation (GSR) pattern is highly significant for determin- ing the solar energy in any particular environment. The current study develops a new mathematical model based on the concept of Functional Data Analysis (FDA) to predict daily-scale GSR in the Burk- ina Faso region of West Africa. Eight meteorological stations are adopted to examine the proposed predictive model. The modeling procedure of the regression FDA is performed using two different internal parameter tuning approaches including Generalized Cross-Validation (GCV) and Generalized Bayesian Information Criteria (GBIC). The modeling procedure is established based on a cross-station paradigm wherein the climatological variables of six stations are used to predict GSR at two targeted meteorological stations. The performance of the proposed method is compared with the panel data regression model. Based on various statistical metrics, the applied FDA model attained convincing absolute error measures and best goodness of fit compared with the observed measured GSR. In quantitative evaluation, the predictions of GSR at the uahigouya and Dori stations attained corre- lation coefficients of R     0.84 and 0.90 using the FDA model, respectively. All in all, the FDA model introduced a reliable alternative modeling strategy for global solar radiation prediction over the Burkina Faso region with accurate line fit predictions.

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  • 291.
    Bey-Gress, Ch.
    et al.
    École nationale supérieure des arts et industries de Strasbourg.
    Laue, Jan
    Institut für Geotechnik, ETH Zürich.
    Seiffert, J-G
    École nationale supérieure des arts et industries de Strasbourg.
    Modélisation de l'interaction sol-fondations superficielles1999Inngår i: Revue Francaise de Geotechnique, ISSN 0181-0529, Vol. 88, nr 3, s. 37-45Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Les ouvrages de génie civil sont classiquementdimensionnés selon les sollicitations qu'ils doiventreprendre, avec des conditions limites locales souventpeu réalistes. Les fondations sont dimensionnées parailleurs, selon les sollicitations transmises, mais en aucuncas la modification du comportement de l'une des partiesn'est prise en compte pour le dimensionnement de l'autrepartie. Il est nécessaire de comprendre d'abord ce qui sepasse au niveau local sol-fondation pour caractériser lecomportement de cet ensemble de propriétés mécaniqueset rhéologiques différentes soumis à des sollicitationscomplexes, avec tous les problèmes inhérents au contact.Le travail présenté concerne des fondations superficiellesposées sur un milieu pulvérulent homogène isotrope,sous des sollicitations de type effort vertical et momentcouplé ou non-couplé.Modelisation

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  • 292.
    Bhagat, Suraj Kumar
    et al.
    Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam. Department of Civil Engineering, Institute of Technology, Ambo University, Ambo, Ethiopia.
    Tiyasha, Tiyasha
    Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam. Department of Civil Engineering, Institute of Technology, Ambo University, Ambo, Ethiopia.
    Welde, Wakjira
    Department of Civil Engineering, Institute of Technology, Ambo University, Ambo, Ethiopia.
    Tesfaye, Olana
    Department of Civil Engineering, Institute of Technology, Ambo University, Ambo, Ethiopia.
    Tung, Tran Minh
    Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Salih, Sinan Q.
    Institute of Research and Development, Duy Tan University, Da Nang, Vietnam.
    Yaseen, Zaher Mundher
    Sustainable Developments in Civil Engineering Research Group, Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
    Evaluating Physical and Fiscal Water Leakage in Water Distribution System2019Inngår i: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 11, nr 10, artikkel-id 2091Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With increasing population, the need for research ideas on the field of reducing wastage of water can save a big amount of water, money, time, and energy. Water leakage (WL) is an essential problem in the field of water supply field. This research is focused on real water loss in the water distribution system located in Ethiopia. Top-down and bursts and background estimates (BABE) methodology is performed to assess the data and the calibration process of the WL variables. The top-down method assists to quantify the water loss by the record and observation throughout the distribution network. In addition, the BABE approach gives a specific water leakage and burst information. The geometrical mean method is used to forecast the population up to 2023 along with their fiscal value by the uniform tariff method. With respect to the revenue lost, 42575 Br and 42664 Br or in 1562$ and 1566$ were lost in 2017 and 2018, respectively. The next five-year population was forecasted to estimate the possible amount of water to be saved, which was about 549,627 m3 and revenue 65,111$ to make the system more efficient. The results suggested that the majority of losses were due to several components of the distribution system including pipe-joint failure, relatively older age pipes, poor repairing and maintenance of water taps, pipe joints and shower taps, negligence of the consumer and unreliable water supply. As per the research findings, recommendations were proposed on minimizing water leakage.

    Fulltekst (pdf)
    fulltext
  • 293.
    Bhanbhro, Riaz
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mechanical Behavior of Tailings: Laboratory Tests from a Swedish Tailings Dam2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Tailings is leftover material from mining industry and is produced in huge quantities approximately 70-99% of the ore production.  Tailings material is stored as impoundments by constructing tailings dams which are often constructed with tailings material itself. Tailings are artificial material and the mechanical behavior of tailings material upon loading is different as compared to natural soil materials. There are number of dam failures reported every year which has severe impact on inhabitants and environment nearby. Considering the failures of tailings dams and consequences there is a need to understand the tailings material in depth for safe existence of these dams. The confident dam design can assure the safe existence of tailings dams for long term as these dams are presumed to function for generations to come. The material properties in tailings dams can change during operation due to raising of new layer. Raised new layer can change stress level, which in turn may change the material properties in terms of strength, pore pressures, grain sizes etc. Today mostly tailings dam are designed by performing analysis for safety for existing and future rasings as well. These analyses are based upon a for certain factor of safety. Not very much can be done with design and analysis for tailings material if the material is not described very well. Understanding of tailings material in depth can provide help for detailed material parameters which later can be used in safety assessment for future raising and changed conditions in dam.

    This study presents the work carried out on tailings material from a Swedish tailings dam. The study is conducted on undisturbed and disturbed tailings material. The undisturbed tests are carried out to understand material properties as per in-situ conditions. Whereas disturbed materials are used to created different materials with different particles sizes. Initially in this study the basic properties of tailings materials are studied e.g. specific gravity, phase relationships, particle sizes, particle shapes and shear behavior on collected samples at various depths. During direct shear tests, the unexpected vertical height reductions were observed, these results are presented in this study. The comparison of strength parameters by direct shear and triaxial tests on material from various depths is also done and presented.

    Based on results from direct shear, triaxial and oedometer tests on uniform sized tailings material; the evaluation of primary and secondary deformations and particle breakage and effect of vertical loads is also carried out and presented. The study also includes the comparison of strength parameters for each particles size. The breakage of particles is analyzed by sieving the material after direct shear tests followed by a particle shape study. The effect of deposition on shear strength parameters is also studied by construction of samples with different angle of deposition of material. The strength parameters of uniform sized particles in triaxial tests are also evaluated and discussed.

    Fulltekst (pdf)
    fulltext
  • 294.
    Bhanbhro, Riaz
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mechanical Properties of Tailings: Basic Description of a Tailings Material from Sweden2014Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Tailings dams are constructed to store waste material from mining industry and usually these dams are raised with time depending upon production rate. Tailings material is sometimes used in construction of tailings dams. Tailings are artificial material and the behavior of tailings material upon loading is different compared to natural soil materials. The mechanical properties of tailings have influence on the performance of a tailing dam. Since the tailings dams are constructed to withstand for long times, it is essential to understand tailings materials in depth in order to assure safe existence of the dams in short term as well as in long term perspective. This licentiate thesis describes the present work carried out on sulphide rich tailings from one mine in Sweden. The material presented is based upon material from three different papers. The first paper describes the basic characteristics of tailings which includes; specific gravity, phase relationships, particle size, particle shape and direct shear behavior. The second paper discusses direct shear tests carried out on tailings from one Swedish mine. Shear strength parameters are evaluated and results from 27 tests (15 drained and 12 undrained tests) are discussed. This paper also describes the vertical height reductions observed during direct shear tests. The third paper focuses on the laboratory results from triaxial tests conducted on tailings materials. This paper shows the drained behavior of tailings under application of different consolidation pressures.The results from particle analysis showed that smaller particles were very angular and bigger particles were sub angular. The material was classified as silt and silty sand. The average particle density (ρs) is 2.83t/m3. The dry density and void ratios were found to be 1.18–1.65 t/m3 and 0.72–1.41 respectively. During direct shear tests vertical height reductions were observed with slight increment in pore pressures. The strain hardening behavior was observed in both drained and undrained conditions in direct shear tests. The strength parameters determined in triaxial test were higher than of those calculated in direct shear tests. Friction angle ϕ' in triaxial tests were found to be 39 to 41degrees and it did not showed any effect with relation to depth. The cohesion and friction angle in direct shear test at 0.15radian, in drained tests were found as in range of 9.7-33.7kPa and 12.5-18.3 degrees respectively. The same parameters for undrained tests were found as 7.1-16.1 kPa and 16.0-20.4 degrees for cohesion and friction angle respectively.

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    FULLTEXT01
  • 295.
    Bhanbhro, Riaz
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Frequent breaches in irrigation canals in Sindh Pakistan2014Inngår i: Journal of Water Resource and Protection, ISSN 1945-3094, E-ISSN 1945-3108, Vol. 6, nr 4, s. 214-223Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Every year a number of breach failures occur in Irrigation Canals in Sindh. Those failures cause displacement of thou-sands of people, destruction of properties, land, and damages costly crops worth millions rupees. In addition to that breach failures are also can cause water shortages when failure occurs during peak demand period. There are various causes of embankment failures that include overtopping, internal erosion, structural defects and piping. State of art for breach failures is presented in this paper and suggestions for prediction of breaches in context to canals in Sindh are discussed. Seepage and slope stability analyses are recommended for long term breach predictions.

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    FULLTEXT01
  • 296.
    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. 

  • 297.
    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.
    Mechanical Behavior of Uniformed Tailings Material in Triaxial Tests2017Inngår i: The Electronic journal of geotechnical engineering, ISSN 1089-3032, E-ISSN 1089-3032, Vol. 22, nr 06, s. 1717-1730Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tailings dams are raised with time depending upon rate of generation of waste. A tailings dam can contain different particle sized materials within its dam body. The newly raised embankment in a tailings dam can be considered as vertical load being applied on subsequent layer. The applied loads can cause deformations and breakage of particles. The particle breakage can then lead to a skeleton with new particle size particles and hence can lead to new material properties. This paper provides the results from triaxial tests conducted on uniformed particle sizes as, 0.5mm-0.25mm, 0.25mm-0.125mm and 0.125mm-0.063mm.  The tests are performed at various effective radial stresses. The results are evaluated and compared with each particle size. The results include stress-strain and volumetric behavior during shearing, the effective stress ratio and stress-dilatancy plot. The friction angles are also evaluated and compared with different particle sized specimens. It was found that effective stress ratios were slightly higher when tests were performed at lower confining stresses and vice versa. It was also observed that particle size did not show any effect of friction angles.

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  • 298.
    Bhanbhro, Riaz
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Roger
    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.
    Mechanical Properties of Soft Tailings from a Swedish Tailings Impoundment: Results from Direct Shear Tests2014Inngår i: The Electronic journal of geotechnical engineering, ISSN 1089-3032, E-ISSN 1089-3032, Vol. 19, nr Z, s. 9023-9039Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The shear strength of tailings can vary depending upon the type of ore and method of construction. Tailings dams may possess loose layers in subsequent layers, which may have low shear strength. Since the tailings dams are made-up to last for longer times, the strength parameters and material behaviors are essential to understand, especially potential for static liquefaction in loose layers. This article presents the results from direct shear tests performed on samples from loose layer of a tailings dam. Both drained and undrained tests are carried out. The results indicated the strain hardening behavior in tailings material which indicates loose condition. The shear strength was found to be relatively low as compared to typical values of tailings in literature. A contractant volume behavior was observed for all the tests. During shear tests the vertical height reductions in samples were observed. These changes were significantly increased after peak shear followed by slight increment in pore pressure along shearing angle. The reasons for these height changes are not fully known, but may be a rearrangement in skeleton or breakage of particles during shear which needs further investigative studies.

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    fulltext
  • 299.
    Bhanbhro, Riaz
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Roger
    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.
    Mechanical Properties of Soft Tailings from different Depths of a Swedish Tailings Dam: Results from Triaxial tests2018Inngår i: Scientia Iranica. International Journal of Science and Technology, ISSN 1026-3098, E-ISSN 2345-3605, Vol. 25, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Construction of tailings dams is done in stages by raising it layer by layer depending on production rate of a mine. These layered dams may possess different strengths and materials properties in each layer i.e. strength parameters, behavior with loading. Tailings dams may have loose layers in subsequent layers, which upon further loading may be susceptible to stability issues. Identification of material properties and behavior is important to know for safety of dam with further raising and long term perspective modeling. This paper presents the results from drained Triaxial compression tests conducted on samples collected from loose layers, from different vertical depths of a tailings dam. The results indicated that depth did not show much influence on strength parameters determined by drained triaxial tests. The different confining pressures influenced the strain-stress behavior, high confining pressures stress-strain curve showed tendency to formulate straighten line of stress-strain curve, with contractant volume behavior along axial strains. The influence of void ratio on effective stress ratio was observed.

  • 300.
    Bhanbhro, Riaz
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Roger
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Rodriguez, Juan
    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.
    Basic description of tailings from Aitik focusing on mechanical behavior2013Inngår i: International Journal of Emerging Technology and Advanced Engineering, ISSN 2250-2459, E-ISSN 2250-2459, Vol. 3, nr 12, s. 65-69Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tailings are artificial granular materials that behave different as compared to natural soil of equal grain sizes. Tailings particle sizes, shapes, gradation and mechanical behavior may influence the performance of tailings dams. Hence it is essential to understand the tailings materials in depth. This article describes present studies being carried out on Aitik tailings. Basic tailings characteristics including specific gravity, phase relationships, particle sizes, particle shapes and direct shear behavior are presented in this article. The results showed that particles size decreases along depth from surface for collected sample locations. The angularity of the particles increases as the grain size decreases. Vertical height reduction was observed during shearing of samples by direct shear tests.

    Fulltekst (pdf)
    FULLTEXT01
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