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  • 1301.
    Yi, Changping
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Sjöberg, Jonny
    Itasca Consultants AB.
    Johansson, Daniel
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Petropoulos, Nikolaos
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    A numerical study of the impact of short delays on rock fragmentation2017Inngår i: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 100, 250-254 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 1302. Young, Raymond N.
    et al.
    Nakano, Masashi
    Pusch, Roland
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Environmental soil properties and behaviour2012Bok (Fagfellevurdert)
    Abstract [en]

    Examining the many changes in soil properties and behavior as a result of stresses from both anthropogenic and environmental forces, this critical work details the requirements of soils to maintain their design engineering properties (rheological, transmission, buffering, and ion-accumulation) over their projected life-spans. It discusses the use of soils as engineered materials in the construction of structures on and in the ground, including foundations, bridges, nuclear waste repositories, tunnels, and other civil infrastructures. The book presents numerous laboratory tests, procedures, techniques, data gathering, data reduction models, and analyses of soil structure.

  • 1303. Yousefi, Bagher
    et al.
    Nordell, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Boroomandnasab, Saeed
    College of Water Science Engineering, Shahid Chamran University, Ahwaz.
    Lindblom, Jenny
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Condensation Irrigation: Field Test in Iran2016Inngår i: Journal of Water Supply: Research and Technology. Aqua, ISSN 1606-9935, E-ISSN 1605-3974Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Due to the growing population and scarcity of fresh water it is increasingly important to produce potable water by desalination of saline water. However, desalination requires energy and in a sustainable world it has to be based on renewable energy. Condensation irrigation (CI) is a method that combines desalination and irrigation. In such systems solar energy could be used to provide needed energy. By letting air flow over the water surface in a solar still with saline or polluted water, the air is humidified. The vapor-saturated airflow is then lead into buried pipes, where the air gradually cools and the water precipitates along the pipe surface. In current field study perforated PVC pipes were used i.e. the condensed water left the pipe through its walls and irrigated the surrounding soil. In PVC pipes without perforations the produced water was collected at the pipe outlet. A fan was used to force the air through the 25 m pipes of the CI system. The resulting amount of produced water per 8 hours for drinking water and irrigation was 4.0 and 6.0 l, respectively.

  • 1304.
    Yu, Y.
    et al.
    Luleå tekniska universitet.
    Axelsson, Kennet
    Luleå tekniska universitet.
    Li, Z. Q.
    Interaction between soil and bored pile based on field tests1991Inngår i: Field measurements in geomechanics: proceedings of the 3rd international sysmposium Oslo / [ed] Geraldine Sorum, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1991, 799-808 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Three long instrumented bored piles have been tested in the ground of a multilayer soil of clay and sand. The shaft load transfer mechanism was investigated with regard to the soil type, pile geometry and test procedures. Additional pile tests of large displacement penetration have also been carried out to study the performance of tip resistance. Special attention is given to the installation procedure of piles, which may play a significant role in the performance of the bored piles.

  • 1305.
    Yu, Yan
    Luleå tekniska universitet.
    Silty landslides in the river valleys of northern Sweden1994Inngår i: Proceedings: Seventh International Congress, International Association of Engineering Geology, 5-9 September 1994, Lisboa Portugal / [ed] R. Oliveira, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1994, 1731-1740 s.Konferansepaper (Fagfellevurdert)
  • 1306.
    Yu, Yao
    Luleå tekniska universitet.
    Constitutive relations for soils and their verifications: a report on the level of development of geomaterial modelling : a state-of-the-art report1988Rapport (Annet vitenskapelig)
  • 1307.
    Yu, Yao
    Luleå tekniska universitet.
    Stability of embankments on sulphide-rich soils1994Rapport (Annet vitenskapelig)
  • 1308.
    Yu, Yao
    Luleå tekniska universitet.
    Testing and modelling of silty and sulphide-rich soils1993Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Silt and sulphide soil are two types of soil which are dominating in northern Sweden, especially in the coast area of the Baltic sea. The stress-strain and strength characteristics of these two soils have so far not been as much explored as those for e.g. Scandinavian clays. With increasing use of numerical methods in geotechnical engineering, better knowledge of the constitutive behaviour of soils is needed as well as more accurate models. The work reported in this thesis is an attempt to achieve such a knowledge for silt and sulphide soil. The drained and undrained stress-strain characteristics of silt have been investigated by means of triaxial compression and extension tests. The compressibility, the dual characteristic of contractancy and dilatancy during shearing, the effect of the clay content and the dependence of the failure surface on the Lode angle have been specially discussed. The drained and undrained stress-strain characteristics of sulphide soil were investigated by means of triaxial and CRS oedometer tests. The compressibility, the effect of the excess pore pressure and the anisotropy have been specially discussed. A plasticity model was proposed for modelling the constitutive behaviour of silt. Among others, the model takes into account the dual characteristic and the dependence of the yield criterion on the Lode angle. An analytical solution was carried out for the undrained triaxial state which links the dilatancy parameter to other parameters. Conditions of material stability were also derived for the triaxial stress state. A plasticity model was proposed for modelling the constitutive behaviour of sulphide soil. Among others, the model takes into account the cohesion and the initial and stress-induced anisotropy. An explicit relation was derived to relate failure or critical state parameters in the isotropic case to those in the anisotropic (K0) case. A calibration method based on optimization was designed to improve the overall quality of model parameters. By using this method, the two proposed models were then calibrated to experimental data from several sets of tests on silt and sulphide soil. Two boundary-value problems, with available data from field tests, were analyzed using a finite element code with the proposed models implemented to demonstrate the capability of the proposed models and of the numerical method.

  • 1309.
    Yu, Yao
    Luleå tekniska universitet.
    Three-dimensional finite element analyses of pile group foundations1993Rapport (Annet vitenskapelig)
  • 1310.
    Yu, Yao
    et al.
    Luleå tekniska universitet.
    Axelsson, Kennet
    Luleå tekniska universitet.
    A plasticity model for silt1992Inngår i: Numerical models in geomechanics: of the fourth International Symposium on Numerical Models in Geomechanics, NUMOG IV, Swansea, U.K., 24-27 August 1992 / [ed] G.N. Pande; S. Pietruszczak, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1992, Vol. 4, 37-45 s.Konferansepaper (Fagfellevurdert)
  • 1311.
    Yu, Yao
    et al.
    Luleå tekniska universitet.
    Axelsson, Kennet
    Luleå tekniska universitet.
    Constitutive driver for response behaviour of soils1992Rapport (Annet vitenskapelig)
  • 1312.
    Yu, Yao
    et al.
    Luleå tekniska universitet.
    Jacobsson, A.
    Geological and geotechnical characteristics of tills for road construction1994Inngår i: Proceedings: Seventh International Congress, International Association of Engineering Geology, 5-9 September 1994, Lisboa Portugal / [ed] R. Oliveira, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1994, 3235-3243 s.Konferansepaper (Fagfellevurdert)
  • 1313.
    Zainy, Maher T.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ask, Maria
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The Tectonic and Structural Classifications of the Western Part of the Zagros Fold and Thrust Belt, North Iraq, Review and Discussion2017Inngår i: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 7, nr 2, 71-89 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Zagros fold and thrust belt represents a tectonically significant area, and one of the richest areas in oil and gas reservoirs in the world. The Zagros fold and thrust belt is the deformational product of the Cretaceous-present day convergence of the Arabian and Iranian (Eurasian) plates (subduction and collision). The belt extends more than 2000 km from southern Turkey through the north and northeastern Iraq to the Strait of Hormuz in southwestern Iran. The Zagros fold and thrust belt is divided into two parts which are; Western part within Iraqi region and Eastern part within Iranian region. The western part of the Zagros fold and thrust belt has been traditionally subdivided into several structural zones that are generally striking parallel to the plate boundary. This is characterized by exposure of Late Ordovician to Pliocene - Pliestocene formations with different types of Quaternary Sediments. This research will concentrate on Western part of Zagros fold and thrust belt and the styles of structural classifications, which will aid to clarify and better understand the tectonic and structural history and evolution of the region. We have considered the last version of structural classification as the most relevant one to the reality, especially within outer platform (Unstable shelf). Where it divides the region into four structural zones, which are: Low Folded zone, High Folded Zone, Imbricate Zone, and Zagros Suture Zone and these zones were further divided to several subzones. This classification is based on the structural style and intensity of deformation, stratigraphy, mechanicalstratigraphy and tectono-stratigraphy of the deformed sequences, Age of deformation, surface physiography and morphology. The data used in the classification is more reliable, up to date and relevant.

  • 1314.
    Zakaria, Saleh
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Rain water harvesting and supplemental irrigation at Sinjar district in northwest Iraq2012Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Rainwater harvesting is one of the methods that can ensure availability of water for winter crop in Iraq. Using this technique the excess rainwater (runoff) is stored in reservoirs of dams of different sizes. The water from these reservoirs can be used later when required to satisfy the crops requirements.It is believed that rainwater harvesting will be one of the solutions to overcome water shortages problem in Iraq.This work deals with rainwater harvesting modeling on Sinjar District. The area of study is a plan area located on the northern and southern flank of Sinjar Mountain, within Nineveh province in northwest Iraq. The model was first applied on southern of Sinjar Mountain, where barley crop was chosen as one of the main crops grown in the area. Linear programming technique was adopted to optimize the irrigated area for irrigation scenario of supplemental irrigation (SI) 100% of full irrigation requirements. Two scenarios of operation were considered for each main basin. In the first, each reservoir was operated as a separate unit while in the second all reservoirs in a basin were operated as one system. Both scenarios gave encouraging results. Scenario two however, was relatively better.And then the model was applied again on the northern Sinjar Mountain area. Wheat crop was considered as the main crop grown in the area. A linear programming technique was adopted to optimize the irrigated area for three scenarios of irrigation. They were: 1/supplemental irrigation (SI) 100%, 2/deficit irrigation (DI) 50%, 3/deficit irrigation (DI) 25% of full irrigation requirements. The results of the three scenarios used indicated that, using deficit irrigation (DI) of 50% can be more beneficial than SI of 100% and DI of 25% of full irrigation requirements. These results reflect useful value of RWH and its influence to increase the irrigated area in the studied region.This study had been carried out at Lulea University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Lulea, Sweden.The present work structured in seven chapters, and can be pursued as follows: In chapter 1, Background of the rainwater harvesting, aims of study and research methodology are addressed. In chapter 2, Scope of description of Water Resources in Iraq, Numbers and facts about Iraq, Present water resources conditions in Iraq, Irrigation practices in Iraq, Main Rivers of Iraq, Dams on Tigris and Euphrates Rivers, The impact of Southeastern Anatolia Project (GAP) on water resources in Iraq, Environmental Consequences and Groundwater in Iraq are described.In chapter 3, Information review on rainwater harvesting and supplemental irrigation is presented. In chapter 4, Description of the study area of the Sinjar District, simulation models used in the study and a research methodology are presented.In chapter 5, The results are presented and discussed for southern and northern of Sinjar Mountain. In chapter 6, Summaries for future study: water harvesting and groundwater recharge, water harvesting and its role in increasing crop productivity and the impact of forecasting on water harvesting. In chapter 7, Summaries for the overall conclusions based on the results and then references of the study are listed.Extended of thesis 1-Water harvesting and reservoir optimization of selected areas south Sinjar Mountain, Iraq, Lulea University of Technology, Sweden.Nadhir Al-Ansari, Mohammad Ezz-Aldeen, Sven Knutsson, Saleh Zakaria Submitted to the Journal of Hydrological Engineering. 2- Rainwater harvesting and supplemental irrigation at northern Sinjar Mountain, Iraq, Lulea University of Technology, Sweden.Saleh Zakaria, Nadhir Al-Ansari, Sven Knutsson, Mohammad Ezz-Aldeen Journal of Purity, Utility Reaction and Environment, Vol. 1 No.3,May 2012, 121-141.

  • 1315.
    Zakaria, Saleh
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Rain Water Harvesting (RWH) North of Iraq2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Rainwater harvesting is one of the methods that can ensure availability of water for winter crop in Iraq. Using this technique the excess rainwater (runoff) is stored in reservoirs of dams of different sizes. The water from these reservoirs can be used later when required to satisfy the crops requirements. It is believed that rainwater harvesting will be one of the solutions to overcome water shortages problem in Iraq.This work includes four parts dealing with macro rainwater harvesting modeling. The study area includes selected sites at three Governorates located north of Iraq (Erbil, Sulaymaniyah, and Nineveh). In part one of the work, three selected sites at south, north and east of Sinjar district (Nineveh Governorate) were used. The slope of the study area at Sinjar district is less than 5%. The technique was first applied on southern Sinjar Mountain. Linear programming technique was adopted to optimize the irrigated area of barley crop for irrigation scenario of supplemental irrigation (SI) 100% of full irrigation requirements. Two scenarios of reservoir operation were considered for each main basin. In the first, each reservoir was operated as a separate unit while in the second all reservoirs in main basin were operated as one system. Both scenarios gave encouraging results. Scenario two however, was relatively better. The technique was applied again on the northern and eastern Sinjar Mountain area but with different catchments area and scenarios of irrigation (supplemental irrigation (SI) 100%, deficit irrigation (DI) 50%, and deficit irrigation (DI) 25% of full irrigation requirements). Wheat crop was considered as the main crop grown in the area. A linear programming technique was adopted to optimize the irrigated area for the above three scenarios of irrigation. The results of the three scenarios used indicated that, using deficit irrigation (DI) of 50% can be more beneficial than SI of 100% and DI of 25% of full irrigation requirements. Part two of the work includes application of Macro RWH technique at mountain areas in Northeastern part of Iraq. In these areas, all selected basins having slope more than 5 % and located at the rain-fed farms of Kurdistan region of Iraq, Erbil and Sulaymaniyah Governorates. The annual rainfall is greater than what was available at Nineveh Governorate. Part three of the work focused about the ability of Macro RWH technique to support wheat crop yield production in dry rain-fed farms at north Sinjar district, north west of Iraq, using wheat crop yield-water relationship that conducted by International Center for Agricultural Research in the Dry Areas (ICARDA). Three scenarios of supplemental irrigation (100%, 75% and 50%) of full irrigation. requirements with, various rainfall conditions were used, two types of wheat (bread and durum) were considered. Part four of the work focused on climatic change and future prospects for Macro RWH technique. Box-Jenkins methodology for time series analysis and forecasting (ARIMA model) was used to study future rainfall for 4 main rainfall stations surrounding Sinjar area in order to forecast expected rainfall for the period 2012-2016. Future rainfall depths were forecasted with adoption of a confidence level of 95%. The future rainfall was employed for RWH technique. This part also includes a review of the impact of climatic change on countries of the Middle East and North Africa (MENA region). The climatic model CGCM3.1 (T47) 2 was used to explain the changes in the average temperatures and rainfall on MENA region with special emphases on Iraq. Long term future seasonal rainfall during the period 2020-2099 at east Sinjar (Nineveh Governorate) showed a clear negative trend reflecting the reduction in total seasonal rainfall amount. For these future rainfall depths, the maximum, minimum and average harvested runoff volumes were estimated. The comparison of the runoff results between future and historical recorded rainfall for the same study area was carried out to show the future validity of rainwater harvesting. In order to estimate the amount of runoff that can be harvested from a given catchment area at eastern Sinjar, an attempt was made to provide set of charts that are easy to be used in order to estimate the equivalent harvested runoff depth (mm) for different selected rainfall depths under different hydraulic conditions for the catchment area. Macro rainwater harvesting (RWH) technique had been tested for future rainfall data that predicted by two emission scenarios of climatic change (A2 and B2) for the period 2020-2099 at Nineveh and Sulaymaniyah Governorates north of Iraq. The results of the four parts of the thesis reflect useful values for RWH and its influence to increase the irrigated area and then the crop yield in the studied region when combined with an effective system like supplemental irrigation. Rain-fed land in the studied areas requires effective technique in terms of saving significant runoff water for irrigation purposes and this might be achieved by rain-water harvesting (RWH) technique.

  • 1316.
    Zakaria, Saleh
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Dawood, Anwer
    Koya University.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Future Prospects for Macro Rainwater Harvesting Technique at Northwest Iraq2014Inngår i: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 4, nr 1, 1-16 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Rainfall data is part of the main components in the hydrological cycle and firmly associated with almost all aspect of climate. Previous research indicated that Macro rainwater harvesting techniques (RWH) can be implemented successfully in Sinjar area northwest Iraq. Recently, prediction of rainfall trends in the Middle East and Iraq in particular suggest a decrease in rainfall due to climate change. This raises the question about the future validity of RWH in the area.In this research, the validity of RWH was investigated using predicted rainfall data in Sinjar area. Eight seasons were selected representing different decades that start 2020 to 2099. The results showed that the maximum, minimum and average harvested future runoff volumes reached about 28.5, 7.61, and 13.9 million cubic meters, that may occurred during the seasons 2055-2056, 2046-2047, and 2065-2066 respectively. The resultant harvested runoff volumes produced by four selected basins at Eastern Sinjar as a catchment area with total area of 435.15 km2. In the second part, an attempt had been made to provide the study area by a set of charts that can help in estimating daily runoff under dry, wet and normal conditions for rainfall depths that ranged between 15 to 55 mm.

  • 1317.
    Zakaria, Saleh
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Ezz-Aldeen, Mohammad
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Rain water harvesting at eastern Sinjar mountain, Iraq2012Inngår i: Geoscience Research, ISSN 0976-9846, E-ISSN 0976-9854, Vol. 3, nr 2, 100-108 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Iraq is facing water shortages and the problem is becoming more serious with time. The main water resources of Iraq (Tigris and Euphrates Rivers) suffer from severe reduction in their discharges due to construction dams on the both banks of Rivers inside Turkey and Syria. Agricultural land had been reduced drastically due to water scarcity. Despite this fact, none of the Iraqi farmers had yet used non-conventional techniques to augment water resources to overcome water shortage problems such as Rainwater Harvesting (RWH) technique.The main aim of this research is to contribute to solving the problem of water shortage of Iraq by finding effective results in terms of saving significant runoff water for irrigation purposes, and therefore provide an academic effort as a tool for encourage and decision support for RWH in Iraq.Macro RWH (large catchment area), was applied at East Sinjar Mountain in Iraq. The estimating volume of harvested runoff ranged (0.11-28.11) ×106 m3 calculated using the Watershed Modeling System (WMS) for the four selected basins together with total area of 435.14 km2 for the study period of (1990-2009).The results of estimating runoff volume showed that the runoff volume can be considered for irrigation practices especially in supplementary irrigation.A linear programming technique was adopted to maximize the irrigated area. Three scenarios of irrigation level were chosen: supplemental irrigation (SI) 100% Satisfy full irrigation requirements (S1), deficit irrigation (DI) 50% of full irrigation requirements (S2), and deficit irrigation (DI) 25% of full irrigation requirements (S3). The resultant irrigated area ranged between 18-2646 for SI 100%, 58-41303 for DI 50%, and 27-9543for DI 25% hectares respectively for all four selected basins together. These results reflect useful value of RWH and its influence to increase the irrigated area in the studied region.

  • 1318.
    Zakaria, Saleh
    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.
    Historical and future climatic change scenarios for temperature and rainfall for Iraq2013Inngår i: Journal of Civil Engineering and Architecture, ISSN 1934-7359, E-ISSN 1934-7367, Vol. 7, nr 12, 1574-1594 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The world is facing a big challenge of climatic change, mainly due to increasing concentrations of greenhouse gases (GHGs) in the atmosphere. Many researches indicated that the climate change occurred disproportionately on developing countries such as Middle East and North Africa (MENA) countries.The climatic model CGCM3.1 (T47) 2 is used in this research to explain the changes in average temperatures and the rainfall on MMENA region with special emphases on Iraq. Historical records (1900-2009) and future (2020-2099) were studied and compared, each period was divided to four sub-periods of thirty years. The results showed that the average monthly temperature for the four historical periods fluctuated between the lowest and highest value as follows: 9.2-32.9, 10.3-32.7, 9.3-32.8, and 8.6-33.9 (Cº).The rainfall for historical periods kept on the same distribution during the past 109 years, and fluctuated between the lowest and highest value of 21.3 and 37.6 mm with an average that reached up to 26.51 mm. For the future period, the maximum average monthly temperature reached up to 37.41 (Cº) during June and minimum average monthly temperature reached up to 4.24 (Cº) during January. The average monthly temperature fluctuated giving a clear impression that the future portends a higher temperature. The average monthly of rainfall, for the future period, fluctuated between the lowest and highest value of 12.91 and 20.63 mm with an average that reached 16.84 mm which represent a reduction percentage of about 36.47% relative to the historical record of rainfall for the same months.

  • 1319.
    Zakaria, Saleh
    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.
    Rainwater harvesting using recorded and hypothetical rainfall data scenarios2013Inngår i: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 3, nr 2, 21-42 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Macro Rainwater Harvesting (RWH) under recorded and forecasting rainfall scenarios helps to overcome the water shortage problem. Eastern Sinjar District-Iraq had been investigated for the potential of RWH with a catchment area of four basins. Three recorded rainfall scenarios (S1, S2, and S3) were diagnosed representing seasons of the maximum, minimum and average weekly rainfall events for the period 1990-2011. Forecasting the rainfall depths for the same catchment area were estimated depending on Box-Jenkins methodology to build Autoregressive Integrated Moving Average (ARIMA) models for weekly rainfall data for the period 2012-2016. Three forecasting rainfall scenarios (S4, S5, and S6) were diagnosed to represent the seasons of the maximum, minimum and average weekly forecasting rainfall events. The results of these scenarios were compared with an average area to be irrigated obtained from the results of 19 years record. The results indicated that in wet years RWH technique with supplemental irrigation help to give total irrigated area larger than a total specified average irrigated area. In average and dry years, the amounts of the additional needed water were estimated to irrigate the total areas that should be increase in order to satisfy the specified average irrigated area.

  • 1320.
    Zakaria, Saleh
    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.
    Wheat yield scenarios for rainwater harvesting at northern Sinjar mountain, Iraq2013Inngår i: Journal of Natural Science, ISSN 0075-4307, Vol. 5, nr 10, 1057-1068 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Iraq is part of West Asia and North Africa (WANA) region. The area is known as dry land, famous with gap of crop yield as a result of the water shortage problem.Six basins with total catchment area of 614.19 km2 at rain-fed of Northern Sinjar District-Iraq had been chosen to investigate both of the potential of rainwater harvesting (RWH) and three supplemental irrigation (SI) scenarios S1, S2, and S3 (100%, 75%, and 50% of full irrigation requirement) to support the wheat yield (bread and durum) under various rainfall conditions for the study period 1990-2009.The results indicated that, the total volume of harvested runoff can be considered for irriga- tion practices, that reached up to 42.4 , 25.1, 0.6, 10.9 (*106 m3) during 1995-1996, 1996-1997, 1998-1999, and 2001-2002, respectively.The total irrigated area ranged between 10.9-5163.7 and 8.8-3595.7 (ha) for bread and durum wheat crop for the four selected seasons respectively. The yield scenarios for supplemental irrigation condition Y1, Y2, and Y3 give 68–9712, 94–12999, and 105–22806 Ton for bread wheat, and for durum wheat give 56–8035, 87–10906, and 103–17396 Ton.

  • 1321.
    Zakaria, Saleh
    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.
    Al-Badrany, Thafer
    University of Mosul.
    ARIMA Models for weekly rainfall in the semi-arid Sinjar District at Iraq2012Inngår i: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 2, nr 3Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Time series analysis and forecasting is an important tool which can be used to improve water resources management. Iraq is facing a severe water shortage problem. The use of rainwater harvesting is one of the techniques to overcome this problem. To put this into practice, it is of prime importance to forecast future rainfall events on a weekly basis.Box-Jenkins methodology has been used in this research to build Autoregressive Integrated Moving Average (ARIMA) models for weekly rainfall data from four rainfall stations in the North West of Iraq: Sinjar, Mosul, Rabeaa and Talafar for the period 1990-2011. Four ARIMA models were developed for the above stations as follow: (3,0,2)x(2,1,1)30, (1,0,1)x(1,1,3)30, (1,1,2)x(3,0,1)30 and (1,1,1)x(0,0,1)30 respectively. The performance of the resulting successful ARIMA models were evaluated using the data year (2011).These models were used to forecast the weekly rainfall data for the up-coming years (2012 to 2016). The results supported previous work that had been carried out on the same area recommending the use of water harvesting in agricultural practices.

  • 1322.
    Zakaria, Saleh
    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.
    Ezz-Aldeen, Mohammad
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Rain water harvesting and supplemental irrigation at northern Sinjar mountain, Iraq2012Inngår i: Journal of Purity, Utility Reaction and Environment, ISSN 2232-1179, Vol. 1, nr 3, 121-141 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Iraq is facing water shortages and the problem is becoming more serious with time. Despite this fact, none of the farmers had used Rainwater Harvesting (RWH) technique yet. The main aim of this research is to contribute to solving the problem of water shortage of Iraq by finding effective results in terms of saving significant runoff water for irrigation purposes. Macro RWH was applied at Northern Sinjar Mountain in Iraq, where macro is indicator for large catchment area. Runoff volume was determined by applying the watershed modeling system (WMS) for six selected basins with total area of 614.19km2 for the study period of (1990-2009). The volume of harvested water ranged (0.6-42.4) × 106 m3 for all six basins together for the study period. A linear programming technique was adopted to optimize the irrigated area for three scenarios of irrigation, 1/ supplemental irrigation (SI) 100%, 2/ deficit irrigation (DI) 50%, 3/ deficit irrigation (DI) 25% of full irrigation requirements. The results of calculation of irrigated area ranged between 14.5-3663.7 for SI 100%, 33.0-39827.1 for DI 50%, and 20.1-7314.0 for DI 25% hectares respectively. These results reflect useful value of RWH and its influence to increase the irrigated area in the studied region.

  • 1323.
    Zakaria, Saleh
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mustafa, Yaseen
    Zakho University.
    Alshibli, Mohammad
    Ministry of Water Resources.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Macro rain water harvesting network to estimate annual runoff at Koysinjaq (Koya) district, Kurdistan region of Iraq2013Inngår i: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 5, nr 12, 956-966 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Macro rainwater harvesting techniques (Macro RWH) are getting more popular to overcome the problem of water scar-city in arid and semi-arid areas. Iraq is experiencing serious water shortage problem now despite the presence of Tigris and Euphrates Rivers. RWH can help to overcome this problem. In this research RWH was applied on Koya city in its districts, North West Iraq. Twenty two basins were identified as the catchment area for the application of RWH tech-nique. Watershed modeling system (WMS), based on Soil Conservation Service - curve number (SCS-CN) method, was applied to calculate direct runoff from individual daily rain storm using average annual rainfall records of the area. Two consecutive adjustments for the curve number were considered. The first was for the antecedent moisture condition (AMC) and the second was for the slope. These adjustments increased the total resultant harvested runoff up to 79.402 *106 m3. The average percentage of increase of harvested runoff volume reached 9.28%. This implies that water allocation is of the order of 2000 cubic meter per capita per year. This quantity of water will definitely help to develop the area.

  • 1324.
    Zakaria, Saleh
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mustafa, Yaseen
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Ahmed, Payman
    Ghafour, Bahra
    Rainwater harvesting at Koysinjaq (Koya), Kurdistan region, Iraq2013Inngår i: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 3, nr 4, 25-46 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Macro Rainwater Harvesting (RWH) has been tested at Koysinjaq (Koya) District, Kurdistan region of Iraq, due to its limited source of water.The studied area consists of four basins with total area of 228.96 km2. The estimating volumes of harvested runoff for the four selected basins together for the study period (2002-2011) were calculated using the Watershed Modeling System (WMS) which is based on Soil Conservation Service Curve Number (SCS-CN) method.In this research, a comparison between maximum and minimum rainfall seasons was conducted to give better understanding for the events that is governing the harvested runoff collection.The results show that, the total harvested runoff ranged from14.83 to 80.77(*106 m3) from the four selected basins together. This indicates that the technique of Macro RWH can be considered to provide a new source of water to contribute to reduce the problem of water scarcity.

  • 1325.
    Zakaria, Saleh
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mustafa, Yassen
    Zakho University.
    Mohammed, Diary
    Sulaimaniya University.
    Ali, Salahalddin
    Sulaimaniya University.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Estimation of annual harvested runoff at Sulaymaniyah Governorate, Kurdistan region of Iraq2013Inngår i: Journal of Natural Science, ISSN 0075-4307, Vol. 5, nr 12, 1272-1283 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Kurdistan Region (KR) of Iraq has suffered from the drought period during the seasons 2007- 2008 and 2008-2009 that affected the human and economic activities of the region. Macro rain- water harvesting (Macro RWH) is one of the te- chniques that can ensure water availability for a region having limited water resources. This te- chnique is based on Soil Conservation Service- Curve Number (SCS-CN) method and the Water- shed Modeling System (WMS) was used to esti- mate the runoff. Rainfall records of Sulaymani- yah area for the period 2002-2012 were studied and an average season was selected (2010-2011). The results of the application of the WMS model showed that about 10.76 million cubic meters could be harvested. The results also showed that the quantity of the harvested runoff was highly affected by rainfall depth, curve number values, antecedent moisture conditions (AMC) and the area of the basins.

  • 1326. Zang, A.
    et al.
    Stephansson, Ove
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik (flyttat 20130630). GFZ German Research Centre for Geosciences, Telegrafenberg, Germany .
    Stress field of the earth's crust2010Bok (Fagfellevurdert)
    Abstract [en]

    This book about rock stress is suitable for students in geosciences and rock engineering, who need to broaden their horizons about the Stress Field of the Earth?s Crust. The book covers the topic so that geosciences students will be able to grasp the Cauchy Stress Principle without fear of matrix transformations in an exercise. Students interested in mathematics, physics and engineering will learn how strain gauges are used to obtain in-situ stress by the overcoring method. Leading edge technology in determining rock stress like quadruple packer and the Kaiser effect are presented together with classical methods like hydraulic fracturing. Borehole techniques (breakouts) and core-based methods (anelastic strain recovery) are illustrated. With respect to stress data, we choose to present the scientific ultra-deep drilling project KTB (Germany), the excavation for nuclear waste disposal at Olkiluoto (Finland) and the drilling into a seismic active fault zone at SAFOD (USA). Stress compilations viewed by the World Stress Map project are presented and interpreted in terms of plate tectonics.

  • 1327.
    Zardari, Muhammad Auchar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mechanical properties of fine grained, sulphur rich, silty soils2010Rapport (Annet vitenskapelig)
    Abstract [en]

    Tailings are the waste products produced during extraction of minerals from the ore. The particle size of tailings varies from medium sand to silt or clay size. Tailings are used as a construction material for raising of embankments called tailings dams. During spigotting, the coarse particles (sands) lie close to the embankment, while the fine particles (slimes) move downwards to the impoundment. The rate of failure in tailings dams is higher than that for the conventional water dams. In the past, tailings dams have failed due to various causes such as meteorological incidents, slope instability, piping/seepage, weak foundations, and seismic liquefaction etc. The statistics shows that the tailings dams are not safe even in their construction stages. The closure and reclamation measures require that the tailings dams and impoundments should be stable for a long time (more than 1000 years). Hence, the proper understanding of the mechanical properties (i.e., permeability, stiffness and strength) of tailings is essential in order to make reliable predictions for the long time stability of tailings dams and impoundments. The purpose of the literature survey carried out is: (a) to understand the mechanical properties of tailings material regarding anisotropy, cyclic loading, particle crushing and creep effects; (b) to know the current design practice and identify the factors that may have strong influence on the long time stability of tailings dams and impoundments, and (c) to find from literature, an appropriate constitutive model that can predict realistic behaviour of tailings material. There is similarity in properties of coarse tailings and loose to medium dense natural sands. Slimes are complex material and may show resemblance to natural sands, clays, or a combination of both. The hydraulic conductivity of tailings varies from point to point in a deposit. Tailings are more compressible than the natural soils. The coefficient of consolidation of slimes is in the range shown by natural clays. Due to high particle angularity, the sands and slimes show higher drained shear strength than that for similar natural soils. Undrained strength of sands is important in evaluation of liquefaction behaviour. The embankments can be raised with upstream, downstream or centreline construction methods. The upstream method is susceptible to liquefaction, whereas the downstream and centreline methods are relatively seismic resistant. The stability of the tailings embankments can be enhanced by keeping the phreatic surface low within the embankment body. The phreatic surface can be lowered with the application of cores, drainage zones, and the use of sand tailings in the embankment construction. Cut-off trenches, slurry walls, grout curtains, and liners can control seepage in tailings dams.The pore water pressures develop during construction of tailings embankments. These pore pressures are described as initial static pore pressure, initial excess pore pressure, and pore pressure due to shearing. The stability analyses conditions for conventional water dams (such as end of construction, staged construction, and long term) are also applicable to the tailings dams. The end of construction condition, and staged construction condition of a tailings dam can be analysed with undrained strength analysis. The drained analysis can be used for the long-term condition of a tailings dam (when an embankment attains maximum height and is constructed slowly). The aim of reclamation measures for tailings dams and impoundments is to achieve long time mass stability, environmental safety, and productive land use. Tailings impoundments can be stabilized with ripraps, chemicals, vegetation, and dry/wet covers etc.Most natural soils show anisotropy in strength due to their depositional history. Due to low density and high degree of saturation, tailings show large cyclic strains in a few cycles of stress reversal. The cyclic strength of tailings can increase with decreasing void ratio. Creep occurs in all soils. Clays show more creep than sands. Loose sands creep more than dense sands. The loads due to high tailings embankments may cause particle crushing and creep. The long time stability of tailings dams and impoundments can be predicted with finite element analysis with suitable constitutive models. The numerical analysis needs to be carried out for severe conditions of rainfalls, floods, and earthquakes.

  • 1328.
    Zardari, Muhammad Auchar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Numerical analyses of stability of a gradually raised tailings dam2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Numerical analyses are presented in this thesis to address potential stability problems that may occur during gradual raisings and under seismic loading conditions of Aitik tailings dam in northern Sweden. The dam is mainly raised using upstream construction method. It is planned to raise the dam gradually in several stages. Two dam parts were studied. The first dam part is a straight dam portion, and the second dam part is a corner. The main concerns associated with future raisings of the straight dam part were: (i) the stability of the dam could be affected by an increase in excess pore pressures during sequential raisings, (ii) how to gradually strengthen the dam by using rockfill berms as supports in such a way that required slope stability can be achieved with a minimum volume of rockfill berms, and (iii) if the dam is subjected to seismic loading, whether or not an increase in excess pore pressures could lead to extensive liquefaction which may cause a failure. The problems related to the dam corner were that tension zones and/or low compression zones could develop because of the horizontal pressure of the stored tailings on the inside of the curvature of the dam corner.Numerical analyses were conducted on both the dam parts using finite element method. Two dimensional (2D) plane strain finite element model was utilized to analyse the straight dam. The dam corner was analysed with both the three dimensional (3D) finite element model, and the 2D axisymmetric finite element model. Coupled deformation and consolidation analyses, and slope stability analyses were performed on both the dam parts to simulate gradual raisings, and to compute safety factors. In addition to this, dynamic analyses were carried out on the straight dam part to evaluate the potential for liquefaction, and seismic stability of the dam. The seismic behaviour of the dam was analysed for two cases: (i) a normal case (earthquake of 3.6 Swedish local magnitude), and (ii) an extreme case (earthquake of 5.8 moment magnitude).The results of the straight dam part, with only previously existing rockfill berms, indicate that stability of the dam was reduced due to an increase in excess pore pressures during raisings. Rockfill berms were utilized as supports to raise the dam with enough safety. An optimization technique was utilized to minimize the volume of rockfill berms. This technique could result in significant saving of cost of rockfill berms.The results of the dam corner show that tension zones and/or low compression zones were located on the surface of the dam corner, mainly above the phreatic level. It is interpreted that there is no risk of internal erosion through the embankments because no seepage path occurs above the phreatic level, and a filter zone exists along the slope of the dam. It is suggested to gradually strengthen the dam corner with rockfill berms. The results of the 2D axisymmetric analyses of the dam corner were in a fairly good agreement with those of the 3D analyses. This implies that the 2D axisymmetric analyses are valid for this dam corner. This is an important finding as 2D axisymmetric analyses require much less computational time compared to 3D analyses.The results of the dynamic analyses performed on the straight dam (including additional rockfill berms) suggest that, for the extreme case, liquefaction could occur in a limited zone that is located below the surface near the embankments. For both the normal and the extreme case, (i) seismically induced displacements seem to be tolerable, and (ii) the post seismic stability of the dam is considered to be sufficient.The findings of this study have been practically applied to the Aitik tailings dam. In general, the modelling procedure and the optimization technique to minimize volume of rockfill berms, presented in this study, could be applied to other tailings dams.

  • 1329.
    Zardari, Muhammad Auchar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Stability of tailings dams: focus on numerical modelling2011Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Upstream tailings dams may experience slope stability problems when the rate of raising is too fast. Tailings consolidate slowly due to low hydraulic conductivity. The excess pore pressures can build up due to accelerated rate of raising. The cumulative increase in excess pore pressures due to successive raisings can endanger slope stability of a tailings dam. The stability of a tailings dam is closely related to the consolidation process. The consolidation process and associated stability of an upstream tailings dam during staged construction was modelled with the finite element program PLAXIS. The analysis indicated that the stability of the dam reduced during raising due to increase of excess pore pressures. The safety of the dam was improved by adding rockfill banks on the downstream side. The volume of the rockfill banks was minimized with an optimization technique. This technique involves (i) construction of a rockfill bank on the downstream side when the factor of safety is less than a permissible limit, (ii) utilization of a minimum volume of the rockfill that is necessary to stabilize the slope. This technique can be practicable when the rate of raising is moderate, and partial consolidation occurs between consecutive raisings. Numerical analysis was also performed on a curved embankment of an upstream tailings dam in order to investigate the possible risk of hydraulic fracturing and internal erosion in a corner of the dam. The analysis showed that low compressive stresses occurred above the phreatic level, near the zones of filter and rockfill banks. These zones contain coarse material, and are, therefore, not susceptible to hydraulic fracturing and internal erosion. An increase in the radius of the corner is suggested in order to prevent large reductions in compressive stresses that may occur due to future raisings. Presently the curved dam section is stable. However, an additional rockfill bank on the downstream side will be required for future raisings. Static liquefaction is considered as a common cause of disastrous flow failures of tailings dams. These flow failures can be predicted with numerical modelling using suitable constitutive models. In this context, some constitutive models capable of simulating static liquefaction behaviour of loose saturated sands are reviewed. It is generally concluded that the finite element method can be a helpful tool for modelling stability of tailings dams.

  • 1330.
    Zardari, Muhammad Auchar
    et al.
    Quaid-e-AwamUniversity of Engineering, Science and Technology, Nawabshah.
    Mattsson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Ormann, Linda
    Fortum, Power Division, Renewable Energy, Våxnäsgatan 10, Box 2087, SE-65002 Karlstad, 8 Sweden.
    Comparison of three-dimensional and two-dimensional axisymmetric finite element analyses of a corner section of a tailings dam2017Inngår i: Scientia Iranica. International Journal of Science and Technology, ISSN 1026-3098, E-ISSN 2345-3605, Vol. 24, nr 5, 2320-2331 s., 9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents three dimensional (3D) and two dimensional (2D) axisymmetric finite element analyses of a corner of a tailings dam. The analyses were performed to: (i) locate tension and/or low compression zones and to evaluate slope stability during sequential raising of the dam corner, and (ii) find whether the results of 2D axisymmetric analyses can be reliable for the dam corner. The corner is a potentially weak section of the dam where tension and/or low compression zones may develop. Development of such zones inside the dam corner can lead to cracks and initiation of internal erosion. The results of both the 3D and 2D axisymmetric analyses indicated that (i) tension and/or low compression zones were located in vicinity of surface of the dam corner mainly above the phreatic level, and (ii) the dam corner is stable up to the planned height if it is gradually strengthened with rockfill berms on the downstream side. The results of 2D axisymmetric analyses showed a fairly good agreement with those of 3D analyses. It is concluded that 2D axisymmetric analyses are appropriate for this dam corner. This implies that significant computational time can be saved by utilizing 2D analyses instead of 3D analyses.

  • 1331.
    Zardari, Muhammad Auchar
    et al.
    Department of Civil Engineering, MUET.
    Ormann, Linda
    Dam Safety Forum, Power Division Renewable Energy.
    Mattsson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Numerical Analysis of Staged Construction of an Upstream Tailings Dam2014Inngår i: Proceedings of 1st National Conference on Civil Engineering (NCCE 2013-14): (Modern Trends and Advancements), Quest Nawabshah, Pakistan: Department of Civil Engineering, Quest Nawabshah, Pakistan , 2014, 150-160 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A case study is presented in this paper which describes finite element analysis of staged construction of the upstream tailings dam Aitik, located in north of Sweden. The purpose of the study is to evaluate stability of the dam for current and future raisings and to strengthen the dam with optimum volume of rockfill banks on the downstream side when stability of the dam is not satisfactory during a construction stage. The finite element method was utilized to model the consolidation process and stability of the dam during the staged construction. The study has shown that stability of the dam during raisings was reduced due to build-up of excess pore pressures. Therefore, the dam was strengthened with rockfill banks on the downstream side to carry out the construction of the dam at a planned rate of raising. An optimization analysis was performed in order to reduce the volume of the rockfill necessary for stabilizing the dam. With the use of the finite element based optimization approach discussed in this paper, stability of the dams during staged construction can be enhanced by utilizing a minimum volume of rockfill banks.

  • 1332.
    Zeinali, Amin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Dagli, Deniz
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Edeskär, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Freezing-Thawing Laboratory Testing of Frost Susceptible Soils2016Inngår i: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM: Reykjavik, Iceland 25th – 28th of May 2016, 2016, 267-276 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Frost heave and thaw weakening are two common concerns in designing and constructing roads throughout cold region areas. Cold regions can be defined in terms of air temperature and frost penetration by frozen ground engineering. Researchers have been studying frost action in soil for the past 85 years in order to design ways to reduce the costly damage to roads. Conducting the test on frost-susceptible soil must be done in order to retrieve data for frost heave and thaw weakening modeling in the soil body during a certain freezing-thawing cycle. This paper reviews and discusses the apparatuses used for this purposes. The studied apparatuses are cylindrical and provide heat through one dimension. The studied apparatuses mostly differ in the diameter and length of their cylindrical cell; likewise, temperature gradients differ from one apparatus toanother. In this study the LTU’s apparatus which was primarily designed to investigate the research related questions concerning freezing and thawing phenomena is presented in detail. The theory of segregation potential is applied for evaluation of the frost heave test and the thaw consolidation theory is applied for the thaw test. The main goal of the project is to conduct a series of experimental tests on various types of soil while exposing them to frost action in the apparatus to propose a classification system for the different types of soil in question with respect to their susceptibility to the frost action phenomena.

  • 1333.
    Zervens, Mikaela
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Samverkansgrundläggning - en sättningsuppföljning av två objekt i Uppsala2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 1334.
    Zhao, Zhihong
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Jing, Lanru
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik, Biogeofysik.
    Neretnieks, Ivars
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Evaluation of hydrodynamic dispersion parameters in fractured rocks2010Inngår i: Journal of Rock Mechanics and Geotechnical Engineering, ISSN 1674-7755, Vol. 2, 243-254 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A numerical procedure to determine the equivalent hydrodynamic dispersion coefficients and Péclet number (Pe) of a fractured rock is presented using random walk particle tracking method. The geometrical effects of fracture system on hydrodynamic dispersion are studied. The results obtained from the proposed method agree well with those of empirical models, which are the scale-dependent hydrodynamic dispersion coefficients in an asymptotic or exponential form. A variance case is added to investigate the influence of longitudinal hydrodynamic dispersion in individual fractures on the macro-hydrodynamic dispersion at the fracture network scale, and its influence is demonstrated with a verification example. In addition, we investigate the influences of directional flow and stress conditions on the behavior of hydrodynamic dispersion in fracture networks. The results show that the magnitudes of the hydrodynamic dispersion coefficients are relatively smaller when the flow direction is parallel to the dip directions of fracture sets. Compressive stresses significantly reduce hydrodynamic dispersion. However, the remaining questions are: (1) whether the deformed fracture network under high stress conditions may make the scale-dependent hydrodynamic dispersion coefficients have asymptotic or exponential forms, and (2) what the conditions for existence of a welldefined equivalent hydrodynamic dispersion tensor are. They need to be further investigated.

  • 1335.
    Zhao, Zhihong
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik, Teknisk geologi och geofysik.
    Jing, Lanru
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik, Teknisk geologi och geofysik.
    Neretnieks, Ivars
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Particle mechanics model for the effects of shear on solute retardation coefficient in rock fractures2012Inngår i: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 52, 92-102 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Damage on rock fracture surfaces during shear process changes the mechanical and hydrological properties of the fractures, therefore, affects the solute migration in fractured rocks. Laboratory experiments on this issue are rarely reported in literature due to technical difficulties in measuring the asperity damage and gouge generation. To conceptually investigate the effects of rock fracture surface damage on solute sorption during shear, this paper presents, for the first time, a retardation coefficient model considering the wear impacts and a generic numerical evaluation procedure. The particle mechanics model was employed to investigate the effects of gouge generation (abrasive wear) and microcrack development in the damaged zones, on the solute retardation coefficient in rock fractures. The results from demonstration examples show that the shear process significantly increases the retardation coefficients, by offering more sorption surfaces in the factures due to gouge generation (wear), microcracking and crushing of gouge particles. Conceptually three damage zones are classified to characterize the various wear impacts on the solute transport in single fractures. Outstanding issues of the present model and suggestions for future study are also presented.

  • 1336.
    Zhao, Zhihong
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Jing, Lanru
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Neretnieks, Ivars
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Moreno, Luis
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    A new numerical method of considering local longitudinal dispersion in single fractures2014Inngår i: International journal for numerical and analytical methods in geomechanics (Print), ISSN 0363-9061, E-ISSN 1096-9853, Vol. 38, nr 1, 20-36 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The solutions of advection-dispersion equation in single fractures were carefully reviewed, and their relationships were addressed. The classic solution, which represents the resident or flux concentration within the semi-infinite fractures under constant concentration or flux boundary conditions, respectively, describes the effluent concentration for a finite fracture. In addition, it also predicts the cumulative distribution of solute particle residence time passing through a single fracture under pulse injection condition, based on which a particle tracking approach was developed to simulate the local advection-dispersion in single fractures. We applied the proposed method to investigate the influence of local dispersion in single fractures on the macrodispersion in different fracture systems with relatively high fracture density. The results show that the effects of local dispersion on macrodispersion are dependent on the heterogeneity of fracture system, but generally the local dispersion plays limited roles on marodispersion at least in dense fracture network. This trend was in agreement with the macrodispersion in heterogeneous porous media.

  • 1337.
    Zhao, Zhihong
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik, Teknisk geologi och geofysik.
    Jing, Lanru
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik, Teknisk geologi och geofysik.
    Neretnieks, Ivars
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Moreno, Luis
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Analytical solution of coupled stress-flow-transport processes in a single rock fracture2011Inngår i: Computers & Geosciences, ISSN 0098-3004, E-ISSN 1873-7803, Vol. 37, nr 9, 1437-1449 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A closed-form solution is presented for modeling the coupled stress-flow-transport processes along a single fracture embedded in a porous rock matrix. Necessary assumptions were made to simplify the subject into a two-dimensional (2D) problem, considering the changes of fracture aperture and matrix porosity under various stress conditions. The cubic law was assumed to be valid for the fluid flow in the fracture, with an impermeable rock matrix. For transport mechanisms, advective transport along the fracture, longitudinal hydrodynamic dispersion in the flow direction, and the matrix diffusion were considered in three different transport models under constant concentration or constant flux (Danck- werts’) inlet boundary conditions. This analytical solution can be used as a constitutive model, or as an example for validation of similar constitutive models, for modeling the coupled hydro-mechanical- chemical (HMC) processes in fracture networks of crystalline rocks. The influences of stress/deformation processes on different transport mechanisms in a single fracture under different inlet boundary conditions were studied for the first time. The results show that changes of fracture, as controlled by a combination of normal closure and shear dilatancy, have a significant influence on the solute concentration distribution both along the fracture and in the rock matrix, as well as on the solute residence/breakthrough time, especially when shear-induced dilatancy occurs. Under compressions, the decreasing matrix porosity slightly increases the solute concentration along the fracture and in the rock matrix.

  • 1338.
    Zhou, Pin
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    The Use of the Continuity Factor as a Tool to Represent Representative Elementary Volume in Rock Engineering Design2014Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 1339.
    Zhou, Pin
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Johansson, Fredrik
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    A comparison between the represenatative volume for circular excavations and rectangular rock mass samplesInngår i: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453XArtikkel i tidsskrift (Annet vitenskapelig)
  • 1340.
    Zhou, Pin
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Johansson, Fredrik
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    On the use of the continuity factor for rock mass properties based on a literature review of the representative elementary volume2014Inngår i: Rock Engineering and Rock Mechanics: Structures in and on Rock Masses - Proceedings of EUROCK 2014, ISRM European Regional Symposium, Taylor & Francis Group, 2014, 427-431 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The REV (Representative Elementary Volume) is widely employed to define the scale limit when the continuum or discontinuum method is suitable for rock mass analyses. A simplified tool is needed as an aid to approximate this limit. The Continuity Factor (CF) was proposed by Palmstrom for this purpose. The definition of the CF implies that the joint spacing is the most significant parameter for the REV. However, other parameters might also influence the REV. In this paper, a literature review of derived REVs is performed. For each REV, the average block size is calculated. The correlation between the REV and the average block size index I-b is thereafter analyzed. The results show that a CF limit of approximately four may exist for the geometrical and the mechanical REV. If other parameters exists that significantly influence the REV are discussed.

  • 1341.
    Zhou, Pin
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Johansson, Fredrik
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Stille, Håkan
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Numerical study on the continuity factor and the limits between continuous and discontinuous behaviors2012Inngår i: ISRM International Symposium 28-30 May 2012, Stockholm, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

     Discontinuum approach or equivalent continuum approach is usually adopted in order to model the behavior of rock masses. The latter approach is more frequently used. However, this approach might be unacceptable for slightly-jointed rock masses. The continuity factor (CF), mainly derived from empirical experience, is defined as the ratio of the tunnel span to the block diameter. It is commonly used to determine whether a rock mass should be modeled as a continuum or a discontinuum material. Only a few analyses regarding the CF have been performed previously. In order to study the limits between continuous and discontinuous behavior, nu-merical analyses with UDEC have been performed. In these analyse, a rock mass with two sets of orthogonal joints are initially generated. From this rock mass, square areas corresponding to a certain CF are randomly chosen as models in UDEC. Confined compression test is conducted on the mentioned model and the constrained modulus (Dm) regarding this rock mass is calculated. Due to the variations of the relative loca-tions between the square and the joints cut inside, as well as the joint quantity and the joint lengths, several Dm are yielded for each CF. Several CFs are also analyzed and the results are compared with previous suggested limits between continuous and dis-continuous behaviors.

  • 1342.
    Zubeck, Hannele
    et al.
    University of Alaska, Anchorage.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Jensen, Pernille
    ARTEK, Technical University of Denmark.
    Nielsen, Mårten Holtegaard
    ARTEK, Technical University of Denmark.
    University of the Arctic's thematic network on Arctic engineering and science2009Inngår i: Cold Regions Engineering 2009: Cold Regions Impacts on Research, Design, and Construction / [ed] John Joseph Hinzmann; Howard D. Mooers, American Society of Civil Engineers (ASCE), 2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Thematic Network in Arctic Engineering and Science (TN AES) was created In June 2008 when it was approved by the University of the Arctic's Council. The TN AES focuses on the development of sustainable technologies through engineering and science in the Arctic. The goals of the TN AES are twofold: The main goal is to improve the quality of life and allow the development of natural resources in the arctic through innovations in technologies used in the construction, maintenance and operation of infrastructure, housing, public/private facilities and equipment. The other goal is to assess the impact of climate change on these technologies. This paper introduces briefly the University of the Arctic to the engineering community and then describes current and planned network activities, such as joint education programs.

  • 1343.
    Åkerlund, Håkan
    Luleå tekniska universitet.
    Deponering av anrikningssand med hjälp av sildammar: rännförsök vid LKABs anläggning i Kiruna2005Rapport (Annet vitenskapelig)
    Abstract [en]

    In mining production, the refining process generates a fine-grained waste rock, called tailings. Tailings and process water is pumped or conducted to a deposit. Usually the deposit is a tailings dam, where the tailings are settled. Though this disposal method is widely used, it has some disadvantages related to the dammed water. In order to reduce the risks, tailings can be disposed under drained conditions with the use of seepage dams. The main issue of a seepage dam will be; filter the tailings and drain the water away. When tailings are disposed under drained conditions the opportunities will be raised to dispose tailings on heights. This provides landscaping possibilities. If waste rock can be used when seepage dams are built, this method will have some economical advantages.In order to find an optimal design of seepage dams with proper performance a number of tests have been carried at LKAB in Kiruna. The tests were accomplished during the summer 2001 in Kiruna. The test plant was set up with three cells with three seepage dams. One seepage dam was built of a fine-grained waste rock originating from mining activities in Kiruna and two seepage dams were constructed with a filter layer made of two different geotextiles. As a support layer a coarse-grained waste rock were used. The size of each cell was 10 * 20 * 2 m3. The filtration and the drainage capacity were measured. A laboratory test preceded the field test where the hydraulic conductivity was measured in two different types of fine grained waste rock.Slurry containing water and tailings was pumped into the test plant with the flow of 6 l/s. The concentration of solids was approximately 35 % by mass. In general, the filtration capacities were high in all seepage dams and, in particular, the seepage dam that was built of fine-grained waste rock. Almost 100 % of all particles were filtrated by the seepage dams. The drainage capacity was measured with piezometers, in one of the cells. They were placed at different depths near the seepage dam. Measured values were compared with those expected based on values if no drainage. After 41 days the pore pressures were decreased 60 %. This will give a proportional increase in shear strength and stability of disposed material. When the water was drained away, the disposed material was settled. The laboratory tests showed relevant values, based on hydraulic conductivity according to literature. Proper materials were found, when filter criteria and hydraulic conductivity were used. The seepage dams showed high filtration capacities which made it possible for fine-grained particles to sediment in the cells. The presence of fine-grained particles influenced the geotechnical properties, such as grain-size, consolidation behaviour and hydraulic conductivity. Though the settled material was drained, still surface water was visible.

  • 1344.
    Åkerlund, Håkan
    Luleå tekniska universitet.
    Dränerad deponering av anrikningssand med hjälp av sildammar: en litteraturstudie2005Rapport (Annet vitenskapelig)
    Abstract [en]

    Mining generates two different types of wastes; a coarse-grained material called waste rock and a fine-grained material called tailings. The most common way of dispose tailings is by mixing it with water and dispose it in a tailings dam. Tailings are settled in the dammed water and redundant water is led back, to be reused in the refining process. Though tailings dams are widely used, they have some drawbacks connected to the dammed water. A method is to be developed where the tailings are disposed in a pond surrounded by seepage dams. Deposit with the use of seepage dams makes it possible to dispose tailings under drained conditions. This also makes it possible to dispose tailings on heights.The task of a seepage dam is to filter solid particles in the slurry and drain water away. This report will compile experiences and knowledge from several deposit methods. In addition, the aim I also to find and identify factors that influence the particle deposition, the filter and drainage capacity of the seepage dams and finally to find out how these factors are connected to each other.

  • 1345.
    Åkerlund, Håkan
    Luleå tekniska universitet.
    Dränerande sildammar för deponering av anrikningssand2005Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [sv]

    Vid gruvbrytning genereras bland annat ett finmalet gråbergsavfall, anrikningssand. Den vanligaste deponeringsmetoden för anrikningssand är att den tillsammans med vatten pumpas eller leds till en gruvdamm. Där deponeras anrikningssanden genom sedimentation. Trots att det är den vanligaste deponeringsmetoden är den behäftad med svagheter. Det uppdämda vattnet i gruvdammen kan ge upphov till incidenter och i olyckliga fall till allvarliga haverier. Ett sätt att minska riskerna och att öka stabiliteten, är att deponeringen sker under dränerade förhållanden. Detta kan åstadkommas med hjälp av sildammar. För att studera funktion och lämplig uppbyggnad av sildammar har ett anta fält- och laboratorieförsök genomförts. Grovkornigt gråbergsavfall, kallat sovringsgråberg, användes när sildammarna byggdes. Sildammarnas uppgift var att hindra flödet av anrikningssand genom filtrering och samtidigt tillåta dränering av inpumpat vatten. Syftet med denna licentiatuppsats har varit att hitta en lämplig design för sildammar. Efter en inledande litteraturstudie byggdes testanläggningar, både som rännförsök och i pilotskala. I testanläggningarna testades olika sildammar genom att dess filtrerande och dränerande förmåga undersöktes. Testerna föregicks av laboratorieförsök där sildammsmaterialens hydrauliska konduktivitet undersöktes. Testerna visar att vid valet av lämpligt material för sildammar, kan filterkriteria användas tillsammans med bedömningar av materialets hydrauliska konduktivitet. Finns inte lämpligt sovringsgråberg att tillgå, kan geotextiler användas som filter i en sildamm. Sildammarnas filtrerande förmåga beräknades som verkningsgrader, vilka låg mellan 34 - 100 % beroende på sildammarnas design. Sildammarnas dränerande förmåga beräknades i det deponerade materialet med hjälp av uppmätta och beräknade porvattentryck. Porvattentrycken sjönk mellan 60 - 100 % under testperioden. Testerna visar att det deponerade materialets egenskaper påverkas av den inpumpade mängden av vatten och anrikningssand samt av sildammarnas funktion. Där sildammens filtrerande förmåga var hög, tog det längre tid innan det deponerade materialet dränerades. Vidare påverkas sildammarnas funktion av det deponerade materialets egenskaper. Vid deponeringen skedde en partikelsegregering, då de tyngsta partiklarna sedimenterade närmast inloppsröret medan lättare partiklar transporterades längre innan de sedimenterade. Denna segregation påverkar sildammens dränerande funktion negativt. Sildammen kan inte filtrera enbart de finkornigaste partiklarna samtidigt som sildammen skall dränera det inpumpade vattnet. Ju mer omfattande partikelsegregationen är och ju bättre sildammen kan hindra de finkornigaste partiklarna, desto större kommer sättningarna i det sedimenterade materialet bli nära sildammen. Detta kan försvåra dränering av ytvattnet. Testerna genomfördes sommartid. Framtida undersökningar bör koncentreras på att anpassa metoden även för vinterförhållanden. Vidare bör materialprover tas för att få en bättre uppskattning av partikelsegregationen. Målet är att kunna beräkna deponins optimala storlek. Slutligen bör ytterligare fältförsök genomföras där anrikningssanden deponeras i våningar. Vid dessa försök bör det deponerade materialets dräneringsförmåga ytterligare utredas tillsammans med undersökningar av eventuella erosionsproblem i underliggande sildammar från dränerat vattnet.

  • 1346.
    Åkerlund, Håkan
    Luleå tekniska universitet.
    Tailings disposal with the use of seepage dams2004Inngår i: Proceedings: NGM 2004. XIV Nordic Geotechnical Meeting, Linköping: Svenska geotekniska föreningen , 2004, G 63- s.Konferansepaper (Annet vitenskapelig)
  • 1347.
    Åkerlund, Håkan
    Luleå tekniska universitet.
    Utformning av sildammar för dränerade deponering av anrikningssand: tester i pilotskala vid LKABs anläggning i Malmberget2005Rapport (Annet vitenskapelig)
    Abstract [en]

    In mining production, the refining process usually generates two different kinds of wastes; tailings and waste rock. Tailings and water from the refining process are pumped or conducted from the refining plant and usually disposed in a tailings dam, containing dammed water and tailings. Though this disposal method is widely used, it has some disadvantages. Most of them are related to the dammed water. To reduce the risks, tailings can be disposed under drained conditions with the use of seepage dams. The purpose of a seepage dam will be to stop the flow of tailing and at the same time drain the water away. An advantage with this method is the possibility to dispose the tailings on heights. This provides landscaping possibilities. If waste rock can be used when seepage dams are constructed the method will be economical beneficial. The aim of this work was to optimize the design of seepage dams. In order to do this a pilot plant was built, containing 4 cells with 4 different seepage dams. The seepage dams where constructed with waste rock. The total flow of tailings and water from the refining process was pumped into the test plant. During operation, the filtration and drainage capacity were measured. In a parallel study, the possibility to dispose tailings direct into waste rock also was tested.The filtration capacities were evaluated with two different methods and coefficients of efficiency were calculated. The coefficients varied between 34 - 100 % depending on the design of the seepage dams. An analysis of the sensitivity of the coefficient of efficiency shows that it will be best calculated based on a comparison between in pumped and disposed volume of tailings. The analysis also shows that the grain density is the parameter having the biggest influence on the calculated coefficient. With one exception, the drainage capacity was high in all cells.The disposal test shows, great variations of the pumped water and tailings. The flow velocity influences the deposition of tailings and the capacity of the seepage dams. In order to reduce this influence, the size of the cells is an important factor. In order to find material for the seepage dam, filter criteria was applied. Hydraulic conductivity of the material in the seepage dam had to be supplemented to find the best material. It is possible to dispose tailings by the use of seepage dams. The possibility to dispose tailings directly into the big heads of waste rock seems to be limited.

  • 1348.
    Åkerlund, Håkan
    et al.
    Sweco AB.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    The use of seepage dams in mine waste disposal2001Inngår i: Securing the Future - International Conference on Mining and Environment, Proceedings: June 25th -July 1st 2001, Skellefteå, Sweden, Stockholm: Swedish Mining Association , 2001, 1-9 s.Konferansepaper (Fagfellevurdert)
  • 1349.
    Åström, Christoffer
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Underlättande protokoll för datahantering inom geoteknik2017Independent thesis Basic level (university diploma), 5 poäng / 7,5 hpOppgave
  • 1350. Ödman, Svante
    et al.
    Levitan, Herbert
    Robinson, Peter J
    Michel, Mary Ellen
    Ask, Per
    Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik. Linköpings universitet, Tekniska högskolan.
    Rapoport, Santley I
    Peripheral nerve as an osmometer: role of endoneurial capillaries in frog sciatic nerve.1987Inngår i: American Journal of Physiology, ISSN 0002-9513, E-ISSN 2163-5773, Vol. 252, nr 3 Pt 1, C335-41 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The sciatic nerve of the frog was perfused in vivo with isotonic Ringer solution followed by Ringer made hypertonic by addition of sucrose or of NaCl. Nerve diameter and endoneurial hydrostatic pressure fell during hypertonic Ringer perfusion. Using a model that describes the elastic and osmotic properties of the nerve, sigma sLp, the product of the osmotic reflection coefficient at endoneurial capillaries for s equals sucrose or NaCl (which approximates 1), and of capillary hydraulic conductivity, was found to equal 73 X 10(-13) cm3 X s-1 X dyn-1. The nerve is elastic. It has a compliance K of 3.7 X 10(-5) cm2 X mmHg-1, corresponding to a modulus of elasticity E of the perineurium equal to 1.2 X 10(6) dyn X cm-2. The results indicate that the nerve behaves as an osmometer during vascular perfusion, due to the low permeability of endoneurial capillaries to small solutes such as NaCl and sucrose. A low capillary hydraulic conductivity limits bulk water flow between blood and nerve, and a low compliance limits nerve swelling and edema.

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