Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 44) Show all publications
Bonath, V., Edeskär, T., Lintzén, N., Fransson, L. & Cwirzen, A. (2019). Properties of ice from first-year ridges in the Barents Sea and Fram Strait. Cold Regions Science and Technology, 168, Article ID 102890.
Open this publication in new window or tab >>Properties of ice from first-year ridges in the Barents Sea and Fram Strait
Show others...
2019 (English)In: Cold Regions Science and Technology, ISSN 0165-232X, E-ISSN 1872-7441, Vol. 168, article id 102890Article in journal (Refereed) Published
Abstract [en]

First-year ice ridges are one of the main load scenarios that off-shore structures and vessels operating in ice-covered waters have to be designed for. For simulating such load scenarios, the knowledge gap on ice mechanical properties from the consolidated part of first-year ridges has to be filled. In total 410 small-scale uniaxial compression tests were conducted at different strain rates and ice temperatures on ice from the consolidated layer of 6 different first-year ridges in the sea around Svalbard. For the first time uniaxial tensile tests were performed on ice from first-year ridges using a new testing method. Ice strength was evaluated for different ice type, which are determined for each specimen based on a proposed ice classification system for ice from first-year ridges. 78% of all samples contained mixed ice with various compounds of brecciated columnar and granular ice. Ice strength of mixed ice showed isotropy, except for the samples containing mainly columnar ice crystals. For horizontal loading, mixed ice was stronger than columnar and granular ice. The residual strength of ductile ice depended on the strain rate. At 1.5% strain remained 70% of peak strength at 10−4 s−1 and 50% at 10−3 s−1. Ductile failure dominated for 75% of all mixed ice tests at 10−3 s−1 and − 10 °C. Ductile compressive strength was generally higher than brittle compressive strength for mixed ice. Brine volume was the main parameter influencing the tensile strength of the mixed ice which was between 0.14 MPa and 0.78 MPa measured at constant ice temperature of −10 °C.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
First-year ice ridges, Ice texture, Uniaxial compression strength, Tensile strength, Mechanical properties
National Category
Other Materials Engineering Geotechnical Engineering
Research subject
Building Materials; Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-76074 (URN)10.1016/j.coldregions.2019.102890 (DOI)2-s2.0-85073186977 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-10-21 (johcin)

Available from: 2019-09-20 Created: 2019-09-20 Last updated: 2019-10-21Bibliographically approved
Edeskär, T. (2018). Longitude profiling as a tool for evaluation of frost actions active pavement section. In: : . Paper presented at 10th International Conference on the Bearing Capacity of Roads, Railways and Airfields, BCRRA 2017; Athens; Greece; 28 - 30 June 2017.
Open this publication in new window or tab >>Longitude profiling as a tool for evaluation of frost actions active pavement section
2018 (English)Conference paper (Refereed)
Identifiers
urn:nbn:se:ltu:diva-72859 (URN)2-s2.0-85058504861 (Scopus ID)
Conference
10th International Conference on the Bearing Capacity of Roads, Railways and Airfields, BCRRA 2017; Athens; Greece; 28 - 30 June 2017
Available from: 2019-02-12 Created: 2019-02-12 Last updated: 2019-02-12
Bhanbhro, R., Edeskär, T. & Knutsson, S. (2017). Effect of Particle Size On Mechanical Properties and Particle Breakage of Tailings. Canadian geotechnical journal (Print)
Open this publication in new window or tab >>Effect of Particle Size On Mechanical Properties and Particle Breakage of Tailings
2017 (English)In: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010Article in journal (Refereed) Submitted
Abstract [en]

Tailings material can have different material properties depending upon the type of ore and ore refining process and particle size distribution. Tailings dams are constructed as walk away solutions. Staged construction of tailings dams may lead to breakage of particles in subsequent layers resulting in change in particle sizes of material. This may lead to change in strength parameters upon change in particle sizes. This paper presents the direct shear tests performed on tailings material from a tailings dam. Remolded samples were manufactured in laboratory. The tailings material is separated in to four different particle sizes i.e.1-0.5mm, 0.5-0.25mm, 0.25-0.125mm and 0.125-0.063mm. The tests are performed on different normal stress levels as 50, 100, 150, 300 and 500kPa.The strength parameters are evaluated for each particle size and compared with said particle sizes. In order to study the effect of deposition, the tests are also performed on same material deposited in vertical and horizontal direction. This paper also describes the study of breakage of particles during direct shear tests by sieving the material at the end of each test. 

Keywords
Direct Simple Shear, Tailings Dams, Tailings Material, Particle Breakage, Vertical Height
National Category
Geotechnical Engineering
Research subject
Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-62681 (URN)
Available from: 2017-03-25 Created: 2017-03-25 Last updated: 2018-04-17
Bhanbhro, R., Edeskär, T. & Knutsson, S. (2017). Mechanical Behavior of Uniformed Tailings Material in Triaxial Tests. The Electronic journal of geotechnical engineering, 22(06), 1717-1730
Open this publication in new window or tab >>Mechanical Behavior of Uniformed Tailings Material in Triaxial Tests
2017 (English)In: The Electronic journal of geotechnical engineering, ISSN 1089-3032, E-ISSN 1089-3032, Vol. 22, no 06, p. 1717-1730Article in journal (Refereed) Published
Abstract [en]

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

Place, publisher, year, edition, pages
Mete Öner, 2017
Keywords
Shear Strength, Triaxial Tests, Tailings Dams, Mechanical Properties, Tailings
National Category
Geotechnical Engineering
Research subject
Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-62645 (URN)
Note

Validerad; 2017; Nivå 1; 2017-04-03 (andbra)

Available from: 2017-03-23 Created: 2017-03-23 Last updated: 2018-11-20Bibliographically approved
Edeskär, T. (2017). Vägytemätning för utvärdering av vägar vintertid. Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Vägytemätning för utvärdering av vägar vintertid
2017 (Swedish)Report (Other academic)
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2017. p. 62
Series
Research report / Luleå University of Technology, ISSN 1402-1528
Keywords
Vägytemätning, tjäle, tjälskador, tillståndsbedömning, vägteknik
National Category
Infrastructure Engineering
Research subject
Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-72485 (URN)978-91-7790-406-9 (ISBN)
Funder
Swedish Transport Administration
Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-06-17Bibliographically approved
Rodriguez, J., Bhanbhro, R., Edeskär, T. & Knutsson, S. (2016). Effect of vertical load on tailings particles (ed.). Journal of Earth Sciences and Geotechnical Engineering, 6(2), 115-129
Open this publication in new window or tab >>Effect of vertical load on tailings particles
2016 (English)In: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 6, no 2, p. 115-129Article in journal (Refereed) Published
Abstract [en]

Tailing dams could store hundreds, thousands or millions of cubic meters of tailings result of the mining extractive industry. Mechanical behavior of this man-made soil should be known in order to maintain a safe storage. Dykes rise up to form the dams and they are buildup with the same tailing material especially in the upstream method using the coarse part. The study uses oedometer classical test to determine the load effect over tailing coarse particles. Tailings are site specific and so its characteristics. It is necessary to understand the tailings degradations to achieve safe impounds. The study comprises four samples of one range-size tailing particles (e.g. 1-0.5, 0.5-0.25, 0.25-0.125, 0.125-0.063mm) subject to vertical load in traditional oedometers. Vertical load effects are measured using two dimensional image analysis and sieving. Results show that 0.063mm sample is the only one that has change in shape with low breakage (<1%) while the rest of the sizes have no shape change but high breakage is present especially in fraction 0.5mm. Settlements also are more pronounced in coarse fractions 0.5 and 0.25mm.

Place, publisher, year, edition, pages
Scienpress Ltd, 2016
National Category
Geotechnical Engineering
Research subject
Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-9274 (URN)7dd7b397-4584-4d2f-a6fe-c34846daea63 (Local ID)7dd7b397-4584-4d2f-a6fe-c34846daea63 (Archive number)7dd7b397-4584-4d2f-a6fe-c34846daea63 (OAI)
Note

Validerad; 2016; Nivå 1; 2016-11-22 (inah)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-12-14Bibliographically approved
Zeinali, A., Dagli, D. & Edeskär, T. (2016). Freezing-Thawing Laboratory Testing of Frost Susceptible Soils (ed.). In: (Ed.), (Ed.), Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM: Reykjavik, Iceland 25th – 28th of May 2016. Paper presented at Nordic Geotechnical Meeting : Challanges in Nordic Geotechnics 25/05/2016 - 27/05/2016 (pp. 267-276).
Open this publication in new window or tab >>Freezing-Thawing Laboratory Testing of Frost Susceptible Soils
2016 (English)In: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM: Reykjavik, Iceland 25th – 28th of May 2016, 2016, p. 267-276Conference paper, Published paper (Refereed)
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.

Series
Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM
Keywords
Civil engineering and architecture - Geoengineering and mining engineering, Frost action, Frost heave, Samhällsbyggnadsteknik och arkitektur - Geoteknik och gruvteknik
National Category
Geotechnical Engineering
Research subject
Soil Mechanics; Sustainable transportation (AERI)
Identifiers
urn:nbn:se:ltu:diva-30685 (URN)493296d9-7230-46cc-b22d-087fbde05c30 (Local ID)493296d9-7230-46cc-b22d-087fbde05c30 (Archive number)493296d9-7230-46cc-b22d-087fbde05c30 (OAI)
Conference
Nordic Geotechnical Meeting : Challanges in Nordic Geotechnics 25/05/2016 - 27/05/2016
Note
Godkänd; 2016; Bibliografisk uppgift: ISBN 978-9935-24-002-6; 20160530 (tomede)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-04-19Bibliographically approved
Bergliv, E. & Edeskär, T. (2016). Laboratory study on two-dimensional image analysis as a tool to evaluate degradation of granular fill materials (ed.). In: (Ed.), Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM: Reykjavik, Iceland 25th – 28th of May 2016. Paper presented at Nordic Geotechnical Meeting : Challanges in Nordic Geotechnics 25/05/2016 - 27/05/2016 (pp. 461-470).
Open this publication in new window or tab >>Laboratory study on two-dimensional image analysis as a tool to evaluate degradation of granular fill materials
2016 (English)In: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM: Reykjavik, Iceland 25th – 28th of May 2016, 2016, p. 461-470Conference paper, Published paper (Refereed)
Abstract [en]

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

Series
Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM
Keywords
Civil engineering and architecture - Building engineering, Ballast, Image analysis, Degradation, Samhällsbyggnadsteknik och arkitektur - Byggnadsteknik
National Category
Geotechnical Engineering
Research subject
Soil Mechanics; Sustainable transportation (AERI)
Identifiers
urn:nbn:se:ltu:diva-32888 (URN)787fa367-534a-45c6-b204-7d63adb98fbb (Local ID)787fa367-534a-45c6-b204-7d63adb98fbb (Archive number)787fa367-534a-45c6-b204-7d63adb98fbb (OAI)
Conference
Nordic Geotechnical Meeting : Challanges in Nordic Geotechnics 25/05/2016 - 27/05/2016
Note

Godkänd; 2016; 20160530 (tomede)

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-04-19Bibliographically approved
Rodriguez, J., Edeskär, T. & Knutsson, S. (2016). Mechanical weathering effect on tailing particles (ed.). In: (Ed.), (Ed.), Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM: Reykjavik, Iceland 25th – 28th of May 2016. Paper presented at Nordic Geotechnical Meeting : Challanges in Nordic Geotechnics 25/05/2016 - 27/05/2016.
Open this publication in new window or tab >>Mechanical weathering effect on tailing particles
2016 (English)In: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM: Reykjavik, Iceland 25th – 28th of May 2016, 2016Conference paper, Published paper (Refereed)
Abstract [en]

Over the last century the tailing volume generation has grown dramatically due to the mineral demand. Nowadays the mining industry is producing every year millions of tons of tailings. The storage of the tailings has become a challenge due to the increased storage capacity demanded. Physical risk associated to the tailings dams is the stability itself since tailing dams are considered a walk-away solution. Physical changes as breakage and shape occur to the tailing particles affecting the stability of the fills by reduced strength properties. In order to understand the reduction and shape changes of tailing particles degradation test by milling attrition (erosion) and image analysis was conducted. Uniform fractions 1-0.5, 0.5-025, 0.25-0.125 and 0.125-0.063mm were used.Results have shown that attrition agents e.g. ball attrition can increase the physical erosion but also change the shape of the particles compared with autogenous attrition. However particles shape has become more regular (less elongated) and rounded in coarse fractions 1-0.5 and 0.5-0.25mm while smaller fractions 0.25-0.125 and 0.125-0.063mm seems to have opposite behavior. Comparison with previous milling studies show consistent differences probably due to the breakage of the particles was the objective. In perspective if tailings become more rounded the strength could be compromised. More studies are needed to verify this.

Series
Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM
National Category
Geotechnical Engineering
Research subject
Soil Mechanics; Sustainable transportation (AERI)
Identifiers
urn:nbn:se:ltu:diva-34637 (URN)8e543d80-16eb-4f95-a3a1-18b125e11f21 (Local ID)8e543d80-16eb-4f95-a3a1-18b125e11f21 (Archive number)8e543d80-16eb-4f95-a3a1-18b125e11f21 (OAI)
Conference
Nordic Geotechnical Meeting : Challanges in Nordic Geotechnics 25/05/2016 - 27/05/2016
Note
Godkänd; 2016; 20151012 (juarod)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-04-17Bibliographically approved
Edeskär, T. & Fredriksson, A. (2016). Statistical analysis of thaw index for thaw weakening design purposes (ed.). In: (Ed.), (Ed.), Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM: Reykjavik, Iceland 25th – 28th of May 2016. Paper presented at Nordic Geotechnical Meeting : Challanges in Nordic Geotechnics 25/05/2016 - 27/05/2016 (pp. 1321-1327).
Open this publication in new window or tab >>Statistical analysis of thaw index for thaw weakening design purposes
2016 (English)In: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM: Reykjavik, Iceland 25th – 28th of May 2016, 2016, p. 1321-1327Conference paper, Published paper (Refereed)
Abstract [en]

In frost action research and design most focus has been put on frost heave. There are several models available to predict frost heave and the concept of statistical re-occurrence times of frost index is commonly used in design. Less effort has been put on thaw weakening modeling and design even though thaw weakening causes a lot of damage on infrastructure such as road and railways. In e.g. Sweden the Transport Administration collects temperature data during the freezing season for frost heave design purposes on project levels but thawing effects are conventionalized by reference tables on a regional level.The aim of this study is to define and quantify the thawing event in such way that it could be applied on a project level in a similar way as temperature measurements are used for frost design. In this study thaw index has been analysed statistically based on air temperature data from 50 stations, collected from year 1951 and onwards by the Swedish Meteorological and Hydrological Institute (SMHI), in Sweden. The temperature thaw seasons have been correlated to the Swedish Transport Administrations frost depth measurement stations.A reference table has been developed based on reoccurrence times of thawing seasons based on the magnitude of thawing index. Based on the statistical distribution of thawing indexes Sweden was divided into three regions in this study. It seems, by statistical means, to be fully possible to develop reference values for thawing periods where thawing index is the working unit. In order to implement the results in e.g. pavement design thawing temperature measurements on a local or semi-regional level are required.

Keywords
Civil engineering and architecture - Building engineering, thaw weakening, thaw design, Samhällsbyggnadsteknik och arkitektur - Byggnadsteknik
National Category
Geotechnical Engineering
Research subject
Soil Mechanics; Sustainable transportation (AERI)
Identifiers
urn:nbn:se:ltu:diva-38768 (URN)d4323efa-7d85-4ea5-8868-cd161d7bb6d4 (Local ID)d4323efa-7d85-4ea5-8868-cd161d7bb6d4 (Archive number)d4323efa-7d85-4ea5-8868-cd161d7bb6d4 (OAI)
Conference
Nordic Geotechnical Meeting : Challanges in Nordic Geotechnics 25/05/2016 - 27/05/2016
Note
Godkänd; 2016; 20160530 (tomede)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2018-04-17Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3390-3113

Search in DiVA

Show all publications