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  • 301.
    Knutsson, Sven
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Rostmark, Susanne
    FriGeo AB.
    Sanera förorenade sediment med frysmuddring2004Ingår i: Bygg och Teknik, ISSN 0281-658X, E-ISSN 2002-8350, Vol. 96, nr 1, s. 71-75Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
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  • 302.
    Knutsson, Sven
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Rydén, Clas-Göran
    Porvattenövertryck i tinande jord1984Rapport (Övrigt vetenskapligt)
  • 303.
    Knutsson, Sven
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Tommik, Karina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Bansal, Tarun
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Motamedi, Zahra
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Tjäle och tjälforskning vid Luleå tekniska universitet2024Ingår i: Bygg & teknik, ISSN 0281-658X, nr 1Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [sv]

    Tjäldjup, tjällyftningar och tjällossningsproblem är årligen återkomman­de fenomen, som inträffar när jordmaterial fryser och tinar. I Sverige är frysningen säsongsmässig, med relativt korta vintrar i söder och upp till sex månader långa i norra Sverige. Tjällossningen sker under våren och avslutas i norra Sverige först vid midsommartid och är inte sällan förknippad med att vägars bärförmåga kan påverkas negativt. Tjäldjupet ökar successivt under vintern med mer eller mindre ojämn tjällyftning som följd. Graden av tjällyftning beror av temperatur i uteluft, jordmaterial och tillgång på vatten. Just ojämnhet i tjällyftningar för vägar och järnvägar är ett problem då det påverkar såväl komfort som säkerhet. Ojämna tjällyftningar behandlas för närvarande i tre olika doktorandprojekt vid LTU och dessa beskrivs här.

  • 304.
    Knutsson, Sven
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Viklander, Peter
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Hur påverkar geotekniska borrmetoder omkringliggande jordmaterial?: Jämförelse av några borrningsmetoders påverkan via fullskaleförsök i Malmberget.2013Ingår i: Bygg och Teknik, ISSN 0281-658X, E-ISSN 2002-8350, nr 1, s. 43-45Artikel i tidskrift (Övrigt vetenskapligt)
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  • 305.
    Knutsson, Sven
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Viklander, Peter
    Kujala, Kauko
    Oulu University of Technology.
    Permeability changes in soil liners due freezing and thawing1998Ingår i: Proceedings of the Symposium on Microstructural modelling og natural and artifically prepared clay soils with special emphasis on the use of clays for waste isolation: Lund, 12-14 October 1998 / [ed] Roland Pusch, Lund, 1998, s. 94-102Konferensbidrag (Refereegranskat)
  • 306.
    Knutsson, Sven
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Vikström, Lars
    LTU.
    Fältförsök av Wavins nedstigningsbrunnar "Euro Manholes"1999Rapport (Övrigt vetenskapligt)
  • 307.
    Knutsson, Sven
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Vikström, Lars
    Luleå tekniska universitet.
    Fältstudie av en axiellt töjbar plastbrunns egenskaper i tjällyftande jord: en fältstudie av "wavinbrunnen"1983Rapport (Övrigt vetenskapligt)
  • 308.
    Knutsson, Sven
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Vikström, Lars
    Luleå tekniska universitet.
    Laboratory study of strength reduction in thawing soils1994Ingår i: Proceedings: Polartech '94 - International Conference on Development and Commercial Utilization of Technologies in Polar Regions, March 22-25, 1994 Luleå, Sweden, Högskolan i Luleå , 1994, s. 425-Konferensbidrag (Övrigt vetenskapligt)
  • 309.
    Knutsson, Sven
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Westerberg, Bo
    Underballast av krossmaterial: dimensioneringsfilosofi1999Rapport (Övrigt vetenskapligt)
  • 310.
    Lagerlund, Johan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Viklander, Peter
    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.
    Design and strength development of a low-mobility grout for repair of embankment damsIngår i: Ground Improvement, ISSN 1365-781X, E-ISSN 1751-7621Artikel i tidskrift (Refereegranskat)
  • 311.
    Larsson, Rolf
    et al.
    Statens Geotekniska Institut.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Tremblay, Maurius
    Statens Geotekniska Institut.
    Öberg-Högsta, Anna-Lena
    Statens Geotekniska Institut.
    Siltjordars egenskaper: silt som konstruktionsmaterial - bestämning av geotekniska egenskaper1998Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    (1) Silt - förekomst och speciella egenskaper; (2) Grundvattenförhållanden och utvärdering av portryck; (3) Tjälproblematik; (4) Fältundersökning; (5) Laboratorieprovning; (6) Beräkning av släntstabilitet och bärighet för fundament; (7) Beräkning av sättningar; Appendix: Beräkning av släntstabilitet till negativa portryck.

  • 312. Larsson, Rolf
    et al.
    Westerberg, Bo
    Albing, Daniel
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Carlsson, Eric
    Sulfidjord: geoteknisk klassificering och odränerad skjuvhållfasthet2007Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    I denna rapport redovisas resultaten av ett forskningsprojekt av skjuvhållfastheten i finkornig sulfidjord längs Norrlandskusten. Undersökningens syfte har varit att på basis av egna resultat och vad som i övrigt är rapporterat i litteraturen beskriva den odränerade skjuvhållfastheten i sulfidjord och att ge rekommendationer för hur den lämpligen bestäms. Eftersom rekommendationerna i många delar skiljer sig från de som ges för annan typ av finkornig jord har det också varit viktigt att klargöra vad som här menas med sulfidjord och hur denna bör klassificeras. Med sulfidjord avses i detta sammanhang sulfidjord i Norrlands kustland, dvs. vad som förr kallades svartmocka. För att räknas in i denna kategori bör jorden ha en organisk halt av minst 1%. I undersökningen har ingått sulfidjordar med lerhalter upp till 40% och organiska halter upp till ca 10%. För eventuellt förekommande sulfidjordar med högre lerhalter och/eller organiska halter bör de utvärderingsregler som gäller för lera och organisk jord användas parallellt. Sulfidfärgad jord inom samma område med organiska halter lägre än 1% bör ur rent geoteknisk synvinkel inte klassificeras som sulfidjord utan behandlas som övrig jord med motsvarande kornfördelning. De aktuella sulfidjordarna har således en sammansättning som enligt geotekniska benämningsregler i huvudsak skulle klassificera dem som organisk silt eller organisk siltig lera och i fall med organiska halter högre än 6% som siltig eller lerig gyttja. Resultaten i denna undersökning visar också att hållfasthetsegenskaperna i sulfidjord normaliserade mot jordens organiska halt och spänningshistoria i stort följer samma mönster som för övrig organisk mineraljord och mineralisk organisk jord. Vad som geotekniskt främst skiljer sulfidjorden från de flesta andra finkorniga svenska jordarna är att den gradvisa övergång med först minskande korsstorlek och sedan ökande organisk halt från silt, siltig lera, lera, organisk lera till organisk jord och som avspeglas i jordens flytgräns, inte gäller för siltig organisk jord som sulfidjord. Detta medför att de empiriska utvärderingar av olika parametrar och försöksresultat som bygger på den nämnda kopplingen till flytgränsen oftast inte kan användas i sulfidjord. Enligt resultaten i denna undersökning bör hållfasthetsvärden för sulfidjord bestämda med fallkonförsök i laboratoriet och vingförsök i fält korrigeras med en faktor av 0,65. Spridningen i resultaten var relativt stor och korrektionsfaktorns variationskoefficient var ca 16-17%. Den odränerade skjuvhållfastheten respektive förkonsolideringstrycket bör ur CPT-sondering i sulfidjord utvärderas med konfaktorerna 20 respektive 4,75. Spridningen i resultaten från CPT-sonderingarna var liten och variationskoefficienterna för konfaktorerna, (faktorerna 20 respektive 4,75), var 10 respektive 8%. I de fall den odränerade skjuvhållfastheten är avgörande och osäkerhet om erforderlig säkerhet mot brott finns, bör komplettering göras med i första hand direkta skjuvförsök. Bedömning av förkonsolideringstrycket ur resultaten av CPT-sonderingar används främst som ett hjälpmedel för att kvalitativt bedöma förkonsolideringstryckets variation mot djupet och att med hjälp därav sammanbinda de enskilda värdena från ödometerförsök. I rapporten ges ett empiriskt samband för uppskattning av den initiella skjuvmodulen. Närmare rekommendationer för hur den odränerade skjuvhållfastheten bör bestämmas ges i kapitlet "Slutsatser och rekommendationer", som bör användas tillsammans med SGI Information Nr 3 (revision 2007) "Utvärdering av odränerad skjuvhållfasthet i kohesionsjord". Kapitlet "Slutsatser och rekommendationer" omfattar också övriga försök som bör utföras för en korrekt klassificering av jorden och för att föreslagna empiriska korrelationer skall kunna utnyttjas.

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  • 313.
    Lintzén, Nina
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Snow storage: modelling, theory and some new research2018Ingår i: Cold Regions Science and Technology, ISSN 0165-232X, E-ISSN 1872-7441, Vol. 153, s. 45-54Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The arrival of natural snow is often delayed nowadays due to global warming. This causes problems for ski resorts and other places where winter activities in different forms take place. Storing snow provides one solution for the winter business industry to deal with this problem. However, there is so far very little research concerning this question. In this paper a review of current knowledge of snow storage and experiences from mainly Scandinavian snow storages is presented. New results concerning melting losses of stored snow from a trial experiment in the north of Sweden are presented. These results are compared to theoretical calculations. The model used for the calculations is shown to be useful for estimating melting losses of insulated piles of snow. Thus the calculations can serve as an important background when designing an insulated snow depot. The model can also be used to compare different insulating materials and to determine properties such as thickness of the insulating layer needed to sufficiently insulate the snow. By minimizing the surface area of insulated snow depots, melt rate due to heat from the air, sun and sky, which constitute the largest part of the total melt, can be reduced. The quality of insulating materials used will be subject to annual observation. Commonly used insulating materials such as bark, wood chips, cutter shavings and sawdust deteriorate.

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  • 314.
    Magnusson, Ove
    et al.
    Skanska.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Behaviour of compacted earth-fill embankments constructed during winter and summer conditions1993Ingår i: Engineered Fills: Proceedings of the Conference Engineered Fills '93, Held on 15-17 September 1993 in Newcastle Upon Tyne / [ed] B. G. Clarke, London: Thomas Telford Ltd , 1993, s. 320-330Konferensbidrag (Refereegranskat)
  • 315.
    Magnusson, Ove
    et al.
    Luleå tekniska universitet.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Deformationer i sommar- och vinterbyggd vägbank: uppföljning av mätningar i fält och laboratorium1992Rapport (Övrigt vetenskapligt)
  • 316.
    Magnusson, Simon
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Lundberg, Kristina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Svedberg, Bo
    Ecoloop, Stockholm.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Sustainable Management of Excavated Soil and Rock: A Literature Review2015Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 93, s. 18-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Construction in developing urban areas implies use of construction materials from quarries and excavation of soil and rock. From a resource perspective, there could be benefits from using excavated soil and rock as a construction material. The aim of this paper is to describe the material flow and management practices of urban excavated soil and rock from the perspective of resource efficiency. A conceptual model for the urban flow of excavated soil and rock was developed and a literature review concerning the management of excavated soil and rock was conducted. The conceptual model was subsequently used to clarify the different perspectives of the scientific literature and knowledge gaps. Conclusions drawn are that there is little knowledge about the quantities and the fate of excavated soil and rock in urban regions. Current research is focusing on the waste flows of construction material and little is known about the overall management practices of excavated soil and rock. Clearly, excavated soil and rock are often disposed at landfills and the recycling rate for high quality purposes is low. There is a need to evaluate the potential for an increased use of excavated soil and rock as construction material. However, the overall efficiency of urban construction material management can only be evaluated and improved by also including construction materials produced in quarries.

  • 317.
    Mainali, Ganesh
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Nordlund, Erling
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Thunehed, Hans
    GeoVista AB, PO Box 276, Luleå, 971 08, Sweden.
    Tailings dams monitoring in Swedish mines using self-potential and electrical resistivity methods2015Ingår i: Electronic Journal of Geotechnical Engineering, E-ISSN 1089-3032, Vol. 20, nr 13, s. 5859-5875Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Tailings dam failures have been occurring in recent years. Many of these failures have caused human casualties, destruction of property, and damage to environment and huge economic loss to the mining industry. The monitoring of the dam is essential to know the existing state of the dams and to ensure the safety of the dam over its life time. The present study has been conducted to test the applicability of electrical resistivity and self-potential (SP), for detecting anomalous seepage through mine tailings dams in Sweden and monitoring the physical condition of the dam. This study has demonstrated the potential of using geoelectrical methods for monitoring the conditions of the tailing dams related to seepage.

  • 318. Makusa, Gregory
    et al.
    Macsik, Josef
    Ecoloop Stockholm.
    Holm, Göran
    Swedish Geotechnical Institute, Linkoping.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Process Stabilization- Solidification and the Physicochemical Factors Influencing the Strength Development of Treated Dredged Sediments2016Ingår i: Geo-Chicago 2016: sustainable waste management and remediation : selected papers from sessions of Geo-Chicago 2016, August 14-18, 2016, Chicago, Illinois / [ed] Nazli Yesiller; Dimitrios Zekkos; Arvin Farid; Anirban De; Krishna R Reddy, Reston, Va: American Society of Civil Engineers (ASCE), 2016, s. 532-545Konferensbidrag (Refereegranskat)
    Abstract [en]

    Process stabilization-solidification (PSS) is a convenient technology for amending high water content dredged sediments (DS) with binders. The PSS equipment comprises of a chassis that carries a pugmill and silos of up to four binders. Primary binders such as cement can be supplemented with pozzolanas materials. In this study, physicochemical interactions of single and composite (ternary) binders on strength development of treated DS are examined based on laboratory and a large-scale field tests. The findings of this study show that the unconfined compressive strength (UCS) depends on the amount of cement in the blend. The UCS decreased with increasing water/cement ratio. It is concluded that (i) the use of constant amounts of composite binder at increasing initial water content of the DS contributes to increased water/cement ratio; (ii) underwater discharge of stabilized DS prior to the initial setting increases the water/cement ratio of stabilized mass; and (iii) presence of mineral admixture hinders strength development of treated dredged sediments

  • 319.
    Makusa, Gregory
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mácsik, Josef
    Ecoloop, Stockholm, Sweden.
    Holm, Göran
    Swedish Geotechnical Institute, Linköping, Sweden.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    A laboratory test study on effect of freeze–thaw cycles on strength and hydraulic conductivity of stabilized dredged sediments2016Ingår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 53, nr 6, s. 1038-1045Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 320.
    Makusa, Gregory P.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mácsik, Josef
    Ecoloop, Stockholm, Sweden.
    Holm, Göran
    Swedish Geotechnical Institute, Linköping, Sweden.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Process stabilization–solidification and physicochemical factors influencing strength development of treated dredged sediments2016Ingår i: Geo-Chicago 2016: Sustainable Waste Management and Remediation / [ed] Nazli Yesiller; Dimitrios Zekkos; Arvin Farid; Anirban De; Krishna R. Reddy, Chicago, Illinois: American Society of Civil Engineers (ASCE), 2016, Vol. GSP 273, s. 532-545Konferensbidrag (Refereegranskat)
    Abstract [en]

    Process stabilization–solidification (PSS) is a convenient technology for amending high water content dredged sediments (DS) with binders. The PSS equipment comprises of a chassis that carries a pugmill and silos of up to four binders. Primary binders such as cement can be supplemented with pozzolanas materials. In this study, physicochemical interactions of single and composite (ternary) binders on strength development of treated DS are examined based on laboratory and a large–scale field tests. The findings of this study show that fixed amount of cement content at increasing initial water content of the DS contribute to decreased level of calcium ions in the blend. Organic matter in the DS retains calcium ions liberated during cement hydration. This causes delay in formation of calcium hydroxide (CH), nucleation and crystallization of calcium silicate hydrates (CSH). Delay in the formation of CH hinders pozzolanic reaction of mineral admixture. Furthermore, increased amount of free water surrounding the stabilized mass causes weakening effect on CSH bond and pH neutralization. It is concluded that strength development of dredged sediments will depend on the amount of cement in the blend in relation to mineral admixture, initial water content of the DS, and the amount of organic matters.

  • 321.
    Makusa, Gregory Paul
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Bradshaw, Sabrina, L.
    University of Wisconsin-Madison.
    Berns, Erin
    University of Wisconsin-Madison.
    Benson, Craig, H.
    University of Wisconsin-Madison.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Freeze-thaw cycling and the hydraulic conductivity of geosynthetic clay liners concurrent with cation exchange2014Ingår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 51, nr 6, s. 591-598Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 322.
    Makusa, Gregory Paul
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mattsson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Investigation of increased hydraulic conductivity of silty till subjected to freeze–thaw cycles2013Ingår i: Mechanical Properties of Frozen Soil, nr STP 1568, s. 33-46, artikel-id STP156820120139Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hydraulic conductivity of silty till increases when the till is subjected to freeze–thaw cycles. A dramatic increase normally occurs after the first freeze–thaw cycle, and the magnitude generally depends on the initial or molding water content. Freezing of silty till causes aggregations of clods and the formation of macrostructure. The initial or molding water content determines the number of freeze–thaw cycles required to complete the agglomeration of clods and the formation of stable macrostructures, which in turn controls the hydraulic conductivity of compacted specimens frozen and thawed in the laboratory. The findings of this study show that for specimens compacted wet of the optimum water content, a significant increase in the hydraulic conductivity was measured after the first freeze–thaw cycle. When specimens were compacted at the optimum water content, a number of freeze–thaw cycles were required in order to obtain the corresponding significant increase in the hydraulic conductivity.

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  • 323.
    Makusa, Gregory Paul
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mattsson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Shear strength evaluation of preloaded stabilized dredged sediments using CPT2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The undrained shear strength of preloaded stabilized dredged sediments increases with curing time. Evaluation of in-situ undrained shear strength using cone penetration test (CPT) data normally requires calibration of the CPT data with known undrained shear strength from vane shear test to obtain the cone factor, which is normally utilized in CPT empirical correlation to estimate the undrained shear strength. In this study, a new CPT empirical correlation for evaluation of in-situ undrained shear strength is presented. The proposed empirical correlation utilizes the effective vertical stress characteristic ratio to estimate the CPT induced stress, which was correlated to the in-situ undrained shear strength. The undrained shear strength computed using the proposed empirical correlation agrees reasonably well with the undrained shear strength estimated using the established empirical correlation at a large-scale field test.

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  • 324.
    Makusa, Gregory Paul
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mattsson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Verification of field settlement of in-situ stabilized dredged sediments using cone penetration test data2012Ingår i: Electronic Journal of Geotechnical Engineering, E-ISSN 1089-3032, Vol. 17Y, s. 3665-3680Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Utilization of in-situ mass stabilization for geotechnical applications is increasing. Laboratory tests may have drawbacks on valuations of engineering parameters for estimations of settlement of in-situ stabilized soil mass. Factors such as compression, mixing work, homogeneity and curing temperature may influence the differences in mechanical properties between laboratory test results and achieved field values. Therefore, utilization of appropriate in-situ mechanical parameters may be required during design analyses. Various in-situ tests are available for use in geotechnical context. Among others, cone penetration test (CPT) is one of most widely used in-situ tests. Numerous CPT empirical correlations are available for use in conventional soils. Utilization of such CPT empirical correlations for in-situ stabilized soils has to be examined. In this paper, the in-situ constrained modulus was evaluated using conventional CPT empirical correlation and utilized as oedometer modulus in finite element analysis for estimation of settlement of preloaded in-situ stabilized dredged sediments. The results show that, computed settlement values fall within the range of measured one. These findings suggest that, the cone penetration test and its empirical correlations, which were established for conventional soils, can also be utilized in stabilized soils.

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  • 325.
    Mattsson, Hans
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Hellström, J. Gunnar I.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Lundström, Staffan
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    On numerical modelling of internal erosion in embankment dams2009Ingår i: Proceedings 1st International Symposium on Rockfill Dams: October 18-21, 2009, Chengdu, China, 2009Konferensbidrag (Refereegranskat)
  • 326.
    Mattsson, Hans
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Zardari, Muhammad Auchar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Ormann, Linda
    Sweco, Karlstad.
    Gruvdammar och deras stabilitet2012Ingår i: Bygg och Teknik, ISSN 0281-658X, E-ISSN 2002-8350, Vol. 104, nr 1, s. 49-52Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 327.
    Mill, O.
    et al.
    Svenska Kraftnät.
    Dahlbäck, N.
    Vattenfall.
    Worman, A
    Kungliga tekniska högskolan, KTH.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Johansson, F.
    Kungliga tekniska högskolan, KTH.
    Andreasson, Patrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Yang, J.
    Kungliga tekniska högskolan, KTH.
    Lundin, U.
    UU.
    Aidanpää, Jan-Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Nilsson, H.
    CTH.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Glavatskih, Sergei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Analysis and development of hydro power research: synthesis within Swedish Hydro Power Centre2010Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The market for hydropower re-investments in Sweden is approx 2.5 billion SEK/yr the coming decade. Large investments will also be carried out in Swedish tailing dams. This will result in challenging projects and need of experts. A crucial factor for a successful management of these challenges is the supply of engineers and researchers with hydro power and dam skills and knowledge. Swedish Hydro Power Centre (Svenskt vattenkraftcentrum, SVC) is a competence centre for university education and research environments within hydro power and mining dams. SVC comprises of two knowledge areas: Hydraulic Engineering and Hydro Turbines and Generators, respectively. SVC builds high-quality and long term sustainable knowledge at selected universities...

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  • 328.
    Mohammad, M. E.
    et al.
    Department of Dams and Water Resources Engineering, University of Mosul, Mosul, Iraq.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Application of SWAT model to estimate the annual runoff and sediment of Duhok reservoir watershed2016Ingår i: Icse 2016 Scour and Erosion Proceedings of the 8th International Conference on Scour and Erosion: Oxford, Uk< 12-15 September 2016 / [ed] Harris, John; Whitehouse, Richard; Moxon, Sarah, London: Taylor & Francis Group, 2016, s. 1129-1136Konferensbidrag (Refereegranskat)
    Abstract [en]

    Estimation of runoff volume and sediment load is a problem that directly affects the performance of dams due to the reduction in the storage capacity of their reservoirs and their effect on dam efficiency and operation schedule. The simulation models can be considered for evaluation of sediment potential if the continuous field measurements are not available. Soil and Water Assessment Tool (SWAT) was applied to estimate the annual runoff volume and sediment load for Duhok Dam Reservoir in north of Duhok/Iraq for the period 1988–2011. The estimated annual runoff volume varied from2.6 to 34.7 MCM. Those values are affected by rainfall depth, intensity and runoff coefficient, while the annual runoff coefficient for the studied area ranged from 0.06 to 0.33 (average is 0.19) causing an average runoff volume of 14.3 MCM. The sediment routing indicated that the values of sediment yields varied from 50 to 1400 t/km2/year depending on sub basin properties. The average annual sediment load from the whole watershed was 124.6 *103 ton. The estimated total sediment arrived to Duhok Reservoir for the considered period 1988–2011 was about 2.99*106 ton.

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  • 329.
    Mohammad, Mohammad E.
    et al.
    Department Dams and Water Resources Engineering, University of Mosul, Mosul, Iraq.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mining and Geotechnical Engineering - Swedish Blasting Research Centre.
    Issa, Issa E.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi. Department Dams and Water Resources Engineering, University of Mosul, Mosul, Iraq.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Sediment in Mosul Dam reservoir using the HEC-RAS model2016Ingår i: Lakes & Reservoirs: Research and Management, ISSN 1320-5331, E-ISSN 1440-1770, Vol. 21, nr 3, s. 235-244Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mosul Dam, located on the Tigris River north of Iraq, is experiencing sedimentation problems, especially near the Al-Jazeera pumping station that supplies the irrigation water for the Al-Jazeera project. The sources of the sediment accumulated within the reservoir are from the Tigris River, as well as ten side valleys on both sides of the reservoir. The sediment inflow rate into the reservoir and the released values are considered on the basis of the operation schedule of the dam for the considered period from 1986 to 2011. The sediment loads were estimated on the basis of available measurements and estimated literature values. The HEC-RAS 4.1 model was used for flows and sediments in the main river and  reservoir. The model was calibrated for flow simulations (coefficient of determination r2 = 0.87) and sediment routing based on bed level, (with resultant r2 = 0.98 and Mean Absolute Deviation of 0.95). The Ackers–White equation was used in the HEC-RAS model for sediment routing because of the wide range of sediment sizes in the study case. The resultant total accumulated sediment load volume was 1.13 km3, a value that is very close to the measured values (1.143 km3) obtained from a previous bathymetric survey. Furthermore, the model indicated most of the sediment (80.7%) was deposited during the first five of the dam operation.

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  • 330.
    Mohammad, Mohammad E.
    et al.
    Department of Dams and Water Resources Engineering, University of Mosul.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Annual Runoff and Sediment in Duhok Reservoir Watershed Using SWAT and WEPP Models2016Ingår i: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 8, nr 7, s. 410-422Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Estimation of runoff volume and sediment load is the main problem that affects the performance of dams due to the reduction in the storage capacity of their reservoirs and their effect on dam efficiency and operation schedule. The simulation models can be considered for this purpose if the continuous field measurements are not available. Soil and Water Assessment Tool (SWAT) andWater Erosion Prediction Project (WEPP) models were applied to estimate the annual runoff volume and sediment load for Duhok Dam Reservoir in north of Duhok/Iraq for the period 1988-2011. The estimated annual runoff volume varied from 2.3 to 34.7 MCM for considered period.Those values were affected by rainfall depth, intensity and runoff coefficient. The resultant annual runoff coefficient for the studied area ranged from 0.05 to 0.35 (average was 0.18) causing an average runoff volume of about 14 MCM. The results of sediment routing indicated that the values of sediment yields varied from 50 to 1400 t/km2/year depending on sub basin properties. The average annual sediment load from the whole watershed is about 120 × 103 ton. The estimated total sediment arrived to Duhok Reservoir for the considered period 1988-2011 was about 2.9 × 106 ton. The results indicate that both models gave reasonable results in comparison with measured values. Based on statistical criteria, the results of both models are close to gather.

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  • 331.
    Mohammad, Mohammad E.
    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.
    Laue, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    A Computational Fluid Dynamics Simulation Model of Sediment Deposition in a Storage Reservoir Subject to Water Withdrawal2020Ingår i: Water, E-ISSN 2073-4441, Vol. 12, nr 4, artikel-id 959Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Siltation is one of the most common problems in storage projects and attached structures around the world, due to its effects on a project’s life span and operational efficiency. A three-dimensional computational fluid dynamics (CFD) model was applied to study the flow and sediment deposition in a multipurpose reservoir (Mosul Dam Reservoir, Iraq) subject to water withdrawal via a pumping station. A suitable control code was developed for the sediment simulation in intakes with multiblock option (SSIIM) model, in order to simulate a study case and achieve the study aims. The measured total deposited load in the reservoir after 25 years of operation and the measured sediment load concentration at different points near the pumping station intake were considered to validate the model results. The sediment load concentrations at several points near the water intake were compared; the percent bias (PBIAS) value was 3.6%, while the t-test value was 0.43, less than the tabulated value, indicating fair model performance. The model sensitivity to grid size and time steps was also tested. Four selected bed level sections along the reservoir were compared with the simulated values and indicate good performance of the model in predicting the sediment load deposition. The PBIAS ranged between 4.8% and 80.7%, and the paired t-test values indicate good model performance for most of the sections.

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  • 332.
    Mohammad, Mohammad E.
    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.
    Laue, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    A numerical study of pumping effects on flow velocity distributions in Mosul Dam reservoir using the HEC‐RAS model2020Ingår i: Lakes & Reservoirs: Research and Management, ISSN 1320-5331, E-ISSN 1440-1770, Vol. 25, nr 1, s. 72-83Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Water flow direction and velocity affect and controls erosion, transport and deposi- tion of sediment in rivers, reservoirs and different hydraulic structures. One of the main structures affected is pumping stations within the dams wherein the velocity distribution near the station intake is disturbed. The two-dimensional (2-D) HEC-RAS 5.01 model was utilized to study, analyse and evaluate the effects of pumping rates and flow depth on the flow velocity distribution, flow stream power and their effects in the Mosul Dam reservoir. The pumping station was considered as a case study. The station is suffering from sediment accumulation around, and in, its intake and suction pipes. The main inflow sources to the reservoir are the Tigris River and run-off from the valleys within its basin. The reservoir was divided into two parts for the present study, including the upper part near the pumping station (analysed as a two-dimen- sional zone), while the lower part was analysed as a one-dimensional flow to reduce the simulation period computation time (1986–2011). Different operation plans (i.e. pumping rate and water depth) were considered. The results of the depth-averaged velocity model indicated that when the pumping station was working at a range from the designed full capacity (100% to 25% of its full capacity), the maximum flow ve- locity increased from 75 to 4 times the normal velocity when there is no pumping dependent on pumping rate and flow depth. For the same operation plans, the flow stream power varied from around zero values to 400 times at full pumping capacity and low flow depth. For sediment routing along the reservoir, the considered statisti- cal criteria indicated the model performance in estimating the total sediment load deposition and invert bed level is much better than in the case of erosion and deposition areas for different considered bed sections of the reservoir.

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  • 333.
    O. Abdullah, Twana
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi. Groundwater Directorate of Sulaimani, Kurdistan Region, Iraq.
    S. Ali, Salahalddin
    Department of Geology, University of Sulaimani, Kurdistan Region, Iraq;Komar University of Science and Technology, Sulaimani, Iraqi Kurdistan Region, Iraq.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Assessment of Groundwater Vulnerability to Pollution Using VLDA and COP Models in Halabja Saidsadiq Basin, Iraq2018Ingår i: Journal of Civil Engineering and Architecture, ISSN 1934-7359, E-ISSN 1934-7367, Vol. 12, nr 11, s. 798-809, artikel-id 003Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Groundwater aquifer in the Halabja and Saidsadiq Basin considered being one of the most important aquifers in terms of water supplying in Kurdistan Region, NE of Iraq. The growing of economics, irrigation and agricultural activities inside the basin makes it of the main essentials to the region. Therefore, pollution of groundwater is of specific worry as groundwater resources are the principal source of water for drinking, agriculture, irrigation and industrial activities. Thus, the best and practical arrangement is to keep the pollution of groundwater through. The current study aims the evaluation of the vulnerability of groundwater aquifers of the study area. Two models were applied, to be specific VLDA and COP to develop maps of groundwater vulnerability for contamination. The VLDA model classified the area into four classes of vulnerability with each covered area: low (2%), moderate (44%), high (53%) and very high (1%). While four vulnerability classes were accomplished dependent on COP model including very low, low, moderate and high vulnerability classes with coverage areas of (1%, 37%, 2% and 60%) respectively. To confirm the suitability of each map for assessment of groundwater vulnerability in the area, it required to be validated of the theoretical sympathetic of current hydrogeological conditions. In this study, groundwater age evaluated utilizing tritium isotopes investigation and applied it to validate the vulnerability results. Based on this validation, the outcome exhibits that the vulnerability classes acquired utilizing VLDA model are more predictable contrasted with the COP model.

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  • 334.
    Ormann, Linda
    et al.
    Dam Safety, Fortum, Power Division Renewable Energy, SE-65002 Karlstad, Våxnäsgatan 10 Box 2087, Sweden.
    Zardari, Muhammad Auchar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mattsson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Bjelkevik, Annika
    Tailings Consultants Scandinavia AB, SE-11156 Stockholm, Kungsgatan 37, Sweden.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Numerical analysis of strengthening by rockfill embankments on an upstream tailings dam2013Ingår i: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 50, nr 4, s. 391-399Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 335.
    Ormann, Linda
    et al.
    Geotechnical Engineer, SWECO Infrastructure AB, Gjörwellsgatan 22, Stockholm.
    Zardari, Muhammad
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mattsson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Bjelkevik, Annika
    Geotechnical Engineer, SWECO Infrastructure AB, Gjörwellsgatan 22, Stockholm.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Numerical analysis of curved embankment of an upstream tailings dam2011Ingår i: Electronic Journal of Geotechnical Engineering, E-ISSN 1089-3032, Vol. 16, nr I, s. 931-944Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A curved embankment (corner) of an upstream tailings dam was analyzed with the finite element method to identify possible zones of low compressive stresses susceptible to hydraulic fracturing that might initiate internal erosion. The embankment was also analyzed as a straight section, with the same cross section as in the corner, in order to compare compressive stresses in the corner and the straight section. The analysis showed that in comparison to the straight section of the dam, the compressive stresses in the corner were (i) much lower above the phreatic level, in the rockfill banks and the filter zones, and (ii) fairly lower below the phreatic level. The rockfill and the filter contain coarse materials, which are not sensitive to hydraulic fracturing and internal erosion. An increase in radius of the corner is proposed to avoid too low compressive stresses that may develop due to future raisings. The slope stability analysis showed that the corner is currently stable, but an additional rock fill bank on the downstream toe is required for future raisings.

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  • 336.
    Osman, Yasin
    et al.
    University of Bolton.
    Abdellatif, Mawada
    Liverpool JM University.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Jawad, Sadeq
    Iraqi Government, Prime Minister Advisory Commission.
    Climate Change and Future Precipitation in Arid Environment of Middle East: Case study of Iraq2017Ingår i: Journal of Environmental Hydrology, ISSN 1058-3912, E-ISSN 1996-7918, Vol. 25, s. 1-18, artikel-id 3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper impact of climate change on precipitation in the arid environment of Iraq is examined.  LARS-WG weather generator was applied to 5 representative regions to model current and future precipitation under climate change. Seven Global Climate Models (GCMs) have been employed to account for any uncertainty on future projection for three selected periods, 2011-2030, 2046-2065 and 2080-2099. Performance of LARS-WG in each site was first evaluated using the Kolmogorov-Smirnov statistical test for fitting wet/dry days in each site, as well as comparison of the mean and standard deviation between the observed and simulated precipitation. The developed LARS-WG models were found to perform well and skilful in simulating precipitation in the arid regions of Iraq as evidenced by the tests carried and the comparison made. The precipitation models were then used to obtain future projections for precipitation using the IPCC scenario SRES A2. Future precipitation results show that most of the Iraq regions are projected to suffer a reduction in annual mean precipitation, especially by the end of the 21st century, while on a seasonal basis most of the regions are anticipated to be wetter in autumn and winter.

     

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  • 337.
    Osman, Yassin
    et al.
    University of Bolton, Bolton, UK.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Adbellatif, Mawada
    Liverpool JM University, Liverpool, UK.
    Al-Jawad, Sadeq B.
    Water Resources, The Prime Minister Office, Baghdad, Iraq.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Expected Future Precipitation in Central Iraq Using LARS-WG Stochastic Weather Generator2014Ingår i: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 6, nr 13, s. 948-959Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Middle East (ME) is characterized by its water shortage problem. This region with its arid climate is expected to be the most vulnerable in the world to the potential impacts of climate change. Iraq (located in ME) is seriously experiencing water shortage problem. To overcome this problem rain water harvesting can be used. In this study the applicability of the long-term weather generator model in downscaling daily precipitation Central Iraq is used to project future changes of precipitation based on scenario of seven General Circulation Models (GCMs) outputs for the periods of 2011-2030, 2046-2065, and 2080-2099. The results indicated that December-February and September-November periods, based on the ensemble mean of seven GCMs, showed an increasing trend in the periods considered; however, a decreasing trend can be found in March, April, and May in the future.

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  • 338.
    Pousette, Kerstin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Eriksson, Lars G.
    MRM Konsult AB.
    Knutsson, Sven
    Acidification properties of sulphide soil - a classification system based on leaching tests2008Ingår i: NGM 2008: Nordisk Geoteknikermøte i Sandefjord 4.- 6. september 2008 / [ed] Kaare Flate; Tor-Erik Frydenlund; Jon Prestegarden; Kåre Senneset, Norsk Geoteknisk Forening , 2008, s. 415-422Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Försurningseffekten från uppgrävd sulfidjord är ett miljöproblem. I ett projekt finansierat av Vägeverket och Banverket har en handbok tagits fram med råd och rekommendationer för hantering av sulfidjordsmassor. I handboken föreslås ett klassificeringssystem för försurningsegenskaperna som bygger på en lakmetodik som har tagits fram av MRM Konsult AB. Resultat från över 100 lakförsök har utvärderats där olika faktorers inverkan på försurningsegenskaperna har studerats.

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  • 339.
    Pousette, Kerstin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Klassificering av sulfidjord med hänsyn till miljö och teknik2007Ingår i: Bygg och Teknik, ISSN 0281-658X, E-ISSN 2002-8350, Vol. 99, nr 1, s. 40-44Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 340.
    Pousette, Kerstin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Study of a sulfide soil deposit at a road construction in Sunderbyn, near Luleå in the north of Sweden2012Ingår i: 7th International Acid Sulfate Soil Conference in Vaasa, Finland 2012, Proceedings volume: Towards Harmony between Land Use and the Environment / [ed] Peter Österholm; Markko Yli-Halla; Peter Edén, Geological Survey of Finland , 2012, s. 86-87Konferensbidrag (Refereegranskat)
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  • 341.
    Pusch, Roland
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Börgesson, Lennart
    Clay Technology, AB.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Origin of silty fracture fillings in crystalline bedrock1990Ingår i: Geologiska föreningens i Stockholm förhandlingar, ISSN 0016-786X, Vol. 112, nr 3, s. 209-213Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Silty fillings in subhorizontal fractures of large area are occasionally found at shallow depth in Swedish bedrock. The soil was deposited after widening of the fractures due to the rock stress conditions at the edge of retreating ice sheets, a probable further implication being artesian conditions leading to hydraulic lifting. It is concluded that if the rate of ice retreat was sufficiently high, the basal part of the ice would be adfrozen to still frozen rock, and highly pressurized meltwater discharged through interconnected, steep and flat-lying fractures, which became filled with soil material transported with the water.

  • 342.
    Pusch, Roland
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Hatem, Mohammed
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Kasbohm, Jörn
    Greifswald University.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Roles of clay and concrete in isolating high-level radioactive waste in very long holes2013Ingår i: International Journal of Research and Reviews in Applied Sciences, ISSN 2076-734X, E-ISSN 2076-7366, Vol. 16, nr 2, s. 263-273Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Groundwater flow transports possibly released radionuclides from underground repositories to the biosphere. It can also make construction difficult as is obvious from examining technical solutions for disposal of high-level radioactive waste (HLW) in long subhorizontally bored holes (KBS-3H) and in very deep boreholes (VDH). The presence of intersected, water-bearing fracture zones requires concrete for sealing these parts of the holes while the rest contains canisters surrounded and separated by dense, expandable clay. Casting of the concrete should be preceded by grouting of the fractured rock using cementitious materials composed so that mutual physical and chemical interaction do not degrade either of them. For the sake of rock stability the horizontal holes have to be located at very moderate depth, 400-500 m, where the rock has a high average hydraulic conductivity, while the slimmer, steep holes reaching down to 4 km are kept stable by using clay mud in the construction phase and dense clay for long term performance. The rock at this depth is much less permeable than higher up and the groundwater sufficiently salt to be maintained there, causing only local thermally induced circulation of possibly contaminated water. The KBS-3H concept involves practical difficulties and risks in the installation of the clay seals and waste canisters, for which the risk of shearing by slip of frequently intersected steep fractures is a major threat after closure of the repository. The VDH concept relies on effective sealing of the upper part of the deep holes and puts less demand on the seals in the lower, waste-bearing part, for which the buoyancy conditions of the groundwater make it a major barrier to upward migration of possibly released radionuclides.

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  • 343.
    Pusch, Roland
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Hatem, Mohammed
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    VDH – a case of ostrich philosophy or a serious alternative for the disposal of highly radioactive waste?2014Ingår i: Waste Management and the Environment VII / [ed] C.A. Brebbia; G. Passerini; H. Itoh, Southampton: WIT Press, 2014, s. 377-390Konferensbidrag (Refereegranskat)
    Abstract [en]

    Two basically different concepts for disposal of highly radioactive waste are the often cited KBS-3 method implying isolation of such waste in copper canisters in short holes bored from tunnels at a depth of a few hundred meters, and disposal in the lower part of 4 km deep holes (VDH). The deep hole concept has the advantage that the waste packages will be located in very salt, stagnant groundwater in rock that is much less permeable than shallow rock with repositories of KBS-3V type. Disadvantages are that some of the techniques for installation have not yet been demonstrated and that retrieval of damaged or stuck canisters is deemed more difficult than for KBS-3V. Both concepts require precise adaption of canister and seal positions to the rock structure, which, for KBS-3 repositories, is not known until the tunnels have been constructed. For VDH, pilot borings provide such knowledge at low cost at a very early stage. The deep holes need to be supported by casings and all work deeper than 500 m must be made with clay mud in them. Reconsideration of the design and function of VDH shows that it has significant advantages, primarily respecting cost and construction time, and that new types of concrete for sealing purposes can make such repositories safer than KBS-3V disposal since seismic and tectonic events are less detrimental and future glaciations will cause much less disturbance. The most important value is that the groundwater that can possibly become contaminated by failing engineered barriers will stay at more than 2000 m depth and that there is no mechanism that can bring it up to the biosphere

  • 344.
    Pusch, Roland
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Kasbohm, Jörn
    GeoENconLtd, Institute of Geography and Geology, Univ. of Greifswald, Germany.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Yang, Ting
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Two genuinely geological alternatives for disposal of highly radioactive waste (HLW)2016Ingår i: Comunicações Geológicas, ISSN 0873-948X, E-ISSN 1647-581X, Vol. 103, s. 25-39Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Disposal of highly radioactive waste (HLW) can be environmentally acceptable if radionuclides are kept isolated from the groundwater, which has inspired planners of repositories to work out multibarrier concepts that postulate defined functions of the host rock and engineered waste confinements. Assessment of the role of the host rock involves groundwater flow modelling and rock mechanical analysis, which are both highly speculative and ignore future changes in rock structure, stress conditions, and groundwater flow. Widening the perspective by considering the integrated physical performance of contacting geological strata respecting groundwater flow conditions can provide excellent isolation of HLW with a minimum of engineered barriers as illustrated by the principle of very deep boreholes (VDH) for which the very high salt content of deep water is the primary barrier by maintaining possibly contaminated groundwater at depth. Such isolation of groundwater regimes can also be obtained by constructing relatively shallow repositories in crystalline rock covered by clay-containing sedimentary rock in regions with no or very low hydraulic gradients. The paper describes a possible case of this type, showing that effective isolation of HLW in repositories of commonly discussed types, KBS-3H and VDH, can be achieved under present climatic conditions.

    The paper compares the short- and long-term functions of repositories located at the southern end of the Swedish island Gotland, being an example of desired geological conditions that are found also in other parts of Sweden and in Lithuania, Germany, Holland and the UK. Here, 500 m of sediment rock series cover gneiss bedrock in which a KBS-3H repository of SKB-type can be built under virtually “dry” conditions because of the tightness of the overlying sedimentary rock and lack of hydraulic gradients in the crystalline rock. Shafts leading down from the ground surface to the repository level are constructed by use of freezing technique and lined with low-pH concrete before installation of waste after which they have to be sealed with expanding clay. Use of initially largely water-saturated clay provides suitable physical properties of the embedment of waste containers. Alternatively, a VDH repository consisting of a number of steep 4 km deep boreholes with about 8oo mm diameter can be driven for installing waste below 2 km depth, leaving the upper 2 km for sealing with clay. The geological conditions, which are also believed to provide acceptable rock pressure conditions for construction of a KBS-3H repository at about 600 m depth, are believed to be suitable for the construction and short- and long-term performance of either repository type. 

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  • 345.
    Pusch, Roland
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Kasbohm, Jörn
    Greifswald University, Germany.
    Hoang-Minh, Thao
    VNU University of Science, Vietnam.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Nguyen-Thanh, Lan
    Technical University of Darmstadt, Germany.
    Holmehus clay — A Tertiary smectitic clay of potential use for isolation of hazardous waste2015Ingår i: Engineering Geology, ISSN 0013-7952, E-ISSN 1872-6917, Vol. 188, s. 38-47Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Danish Tertiary Holmehus clay belongs to the series of illite-smectite mixed-layer clays in northern Europe and has a potential to serve as an effective engineered barrier for isolating hazardous waste. Mineralogical specification was made of the components illite/smectite mixed-layer and dioctahedral vermiculite/smectite mixed-layer structures. The lower content of expandable phase than of smectite- rich clays like MX-80 gives somewhat higher hydraulic conductivity and somewhat lower swelling pressure but both are deemed suitable for isolating canisters with high-level radioactive waste in deeprepositories for densities at water saturation of at least 1900 kg/m3. The lower swelling pressure, the potential of being chemically more stable, and the high buffer capacity by providing dissolved Si makes Holmehus clay a candidate for use in both deep and near-surface repositories.

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  • 346.
    Pusch, Roland
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Kasbohm, Jörn
    Greifswald University, Germany .
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Hoang-Minh, Thao
    Greifswald University, Germany .
    Nguyen-Thanh, Lan
    Technical University of Darmstadt, Germany.
    Disposal of Low- and Intermediate-Level Radioactive Waste2019Ingår i: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 9, nr 3, s. 237-272Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As for isolation of high-level radioactive waste by use of smectite clay it serves very well also for hindering radionuclides from low- and intermediate-level waste to contaminate groundwater. It can be used for minimizing groundwater flow through and along waste packages and for providing them with ductile embedment for eliminating the risk of damage caused by displacements in host rock or concrete vaults. The clay can have the form of liners placed and compacted on site over vaults constructed on the ground surface, or consist of compacted blocks of clay granules that are tightly placed around waste packages in underground drifts and rooms. In either case the initially incompletely water saturated clay will swell in conjunction with water uptake until tight contact with the confining medium has been established. The clay seals must be sufficiently dense to fulfill criteria set with respect to hydraulic conductivity and swelling capacity, paying due attention to the salt content in the porewater. Their physical and chemical stabilities must be acceptable in short- and long-term perspectives, which is a few hundred years for most low-level wastes up to tens of thousands of years for long-lived waste. 

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  • 347.
    Pusch, Roland
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Kasbohm, Jörn
    Greifswald University.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Yang, Ting
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Nguyen-Thanh, Lan
    Technical University of Darmstadt.
    The role of smectite clay barriers for isolating high-level radioactive waste (HLW) in shallow and deep repositories2015Ingår i: Procedia Earth and Planetary Science, E-ISSN 1878-5220, Vol. 15, s. 680-687Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The major engineered barriers to migration of radionuclides from HLW in repositories are the canister and surrounding smectite clay. They interact physically and chemically by which the properties of both are changed, especially of the smectite “buffer” clay that is examined in the paper. The canisters are made of copper-lined iron according to the Swedish and Finnish concepts, steel being an alternative. The function of the host rock is of importance and the paper examines the role of two repository concepts with long subhorizontal or deep vertical holes for placing the waste. The hydraulic conductivity of the canister-embedding smectite clay can be significantly raised by high temperature and temperature gradients, which generate precipitation of salt and silica in different parts of the buffer clay. The impact of the degrading processes on the waste-isolating capacity is different for shallow repositories in permeable rock and for very deep disposal with higher temperature. The latter has stagnant groundwater as major barrier to the migration of radionuclides.

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  • 348.
    Pusch, Roland
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Taie, Laith
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    The impact of hydraulic gradients and boundary conditions on the microstructural stability of clayey backfills with special respect to the risk of piping and erosion2012Ingår i: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 2, nr 1, s. 89-112Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Disposal of hazardous waste like high-level radioactive waste (HLW) is made by confining it in canisters surrounded by dense, ductile “buffer” clay for placement in deposition holes at a few hundred meters depth in crystalline rock. The concept favoured by authorities in Sweden, Finland and Canada implies that the holes are bored from blasted or bored tunnels to be tightly backfilled by stacking compacted blocks of clay in the center and filling the remaining space between the blocks and the rock with blown-in clay pellets. The problem with this is that water flowing in from the rock can cause piping and erosion of the pellet filling, which can turn it into mud and disturb the placement of canisters and buffer clay. The controlling parameter is the rate of inflow of water per inflow point, which is determined by the structure and hydraulic conductivity of the rock. The paper describes a simple model of the mechanisms in penetration of water into the pellet fill and provides a basis for estimating the required rate of backfilling for avoiding critical conditions. The study indicates that such conditions will be caused irrespective of the rate of water inflow per point if the backfilling rate is low.

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  • 349.
    Pusch, Roland
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Taie, Laith
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Hatem, Mohammed
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Optimal ways of disposal of highly radioactive waste2012Ingår i: Natural Science, ISSN 2150-4091, E-ISSN 2150-4105, Vol. 4, nr 11A, s. 906-918Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multibarrier concepts are commonly proposed for effective isolation of highly radioactive waste (HLW). Present concepts consider the host rock as a barrier by retarding migration of possibly released radionuclides to the biosphere, containers for preventing release of radionuclides, and “buffer clay” embedding the canisters for providing ductility and minimizing the risk of container breakage and for delaying migration of possibly escaping radionuclides. Closer analysis of the isolating functions shows that rock will only serve as a mechanical protection of the “nearfield”, the containers of proposed types can be short-lived, and the surrounding clay will be increasingly permeable and stiffen hence becoming less ductile with time. A different approach, representing an alternative to the common concepts, can be safer and cheaper. It takes the HIPOW copper canister as the only major barrier and a cheap but sufficiently efficient buffer as embedment. The repository can consist of an abandoned copper mine, an option being to place HLW in emptied drifts while mining is still going in not yet exploited parts of the ore body.

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  • 350.
    Pusch, Roland
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Taie, Laith
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Shahrestanakizadeh, Mehras
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Isolation of hazardous soil contaminated by DU (depleted uranium) from groundwater2012Ingår i: Waste Management and the Environment VI / [ed] V. Popov; H. Itoh; C.A. Brebbia, WIT Press, 2012, s. 297-308Konferensbidrag (Refereegranskat)
    Abstract [en]

    Cappings of waste piles conventionally contain a drain layer over a low-permeable clay liner composed of smectite minerals. The rate of percolation of the clay liner, once it has been largely water saturated, determines the downward migration of water into and through the underlying waste. In desert climate, cyclic variation in the degree of hydration of the clay takes place, from desiccated to largely water saturated conditions. Clays of smectite type effectively seal off the underlying waste but the content must be low for preventing contraction and expansion causing a reduced isolation potential of the liner. Penetration of the liner, implying wetting of the waste, starts when the top liner is largely water saturated but the hydration followed by dehydration is confined to take place only to a limited depth according to the assumed wetting mechanism. The rate of wetting usually follows a log time law. For an ideal composition and density of the upper clay liner there will be no percolation and wetting of the underlying waste. The paper is focused on the mechanisms involved in hydration/dehydration of top clay liner prepared by mixing clay and ballast material for providing a basis for design, construction and maintenance of well performing cappings.

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