| 1. |
- Bergliv, Elin, et al.
(författare)
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Laboratory study on two-dimensional image analysis as a tool to evaluate degradation of granular fill materials
- 2016
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Ingår i: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM. ; , s. 461-470
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 2. |
- Bergliv, Elin
(författare)
-
Large-scale testing of granular material
- 2022
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main problem to investigate in this study is if larger grained materials, up to 200 mm nominal size, could be used as an embankment material for high-speed railways. High-speed railways have very strict settlement requirements, allowing only very small settlements to ensure safety.To be able to test large grained materials, large devices and unique equipment is needed, something that makes testing and laboratory investigations rarer with increasing grain size. The studies that have been done focus on materials up to about 200 mm nominal size. The literature review finds that there is unclear common conception of how grain size influences the shear strength and deformation properties of a soil material. The most common finding is that increasing grain size results in lower shear strength and increased deformations. Some studies found the opposite and some found no influence of grain size on shear strength. One observation is that the shear strength tends to be unaffected by grain size if the grain strength is equal for all grain sizes. Otherwise the general impression is that larger grains tend to have higher occurrence of fractures and cracks, lowering the grain strength.The study presented herein is performed with a newly developed large-scale simple direct shear device. This device allows testing of grains up to 200 mm grain size. The design includes a free-standing load frame, where the sample is placed in a steel-wire lined rubber membrane on a swing. There are two actuators, one applies vertical force on the sample, while the other applies the shearing motion of the swing. The design is new and allows large forces in both vertical and horizontal direction, without pre-stressing the device.A total of six series are performed on materials with varying grain size, gradation, and grain shape. The findings of the laboratory study includes higher shear strength of well-graded material with larger grains (0-200 mm) compared to a uniformly graded sand with grain size 0-2 mm. The main challenge with the laboratory testing was handling the large amounts of soil material needed for each sample, making it difficult to control the initial void ratio. This is a drawback when analysing the deformation behaviour of the tests. The general behaviour was that the samples underwent initially contraction, which ended with dilatancy and most test reached net increase of volume by the end ofthe shearing.
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| 3. |
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| 4. |
- Berglund, Andreas, et al.
(författare)
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Comparison between temperature based thaw weakening prediction model and field observation methods
- 2011
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Ingår i: Proceedings of the 21st International Conference on Port and Ocean Engineering under Arctic Conditions. - Montreal.
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Konferensbidrag (refereegranskat)abstract
- Structures like roads and port yards located in cold climate are affected by freezing and thawing every year. The global trend of a warmer climate and temperatures around 0°C for longer periods of time will change the freezing/thawing behaviour in many locations. The tendency will changeto have several freezing /thawing cycles in a given location every year. The bearing capacity of low volume roads and simple port yards will be affected by a prolonged thawing period with lower bearing capacity as a consequence. Bearing capacity problems can lead to increased costs for traffic as well as increased maintenance costs. Due to very high costs for destroyed structuresduring thaw, a lot can be gained if bearing capacity problems at a given site can be forecasted well in advance in order not to destroy the structure. Such a method should preferably be based upon simple measurements like air temperatures to make it easy to use also in remote areas. In the described temperature based model air and ground temperatures are used to develop anaccumulated thaw index and corresponding limits. When the thaw index limit is reached, the construction at the evaluated depth thaws, leading to increased pore water pressure and reduction of strength and bearing capacity. This paper presents a study of the application of the model at low volume roads in Sweden. Bearing capacity at the road was evaluated from field tests by falling weight deflectometer (FWD) test carried out 24 times during the thawing season i.e.March 4 through June 9. Predictions made by the model were compared with the subgrade module evaluated from the FWD series. The results show that the model might be possible to use in Sweden and elsewhere if minor adjustments are carried out.
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| 5. |
- Bhanbhro, Riaz, et al.
(författare)
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Basic description of tailings from Aitik focusing on mechanical behavior
- 2013
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Ingår i: International Journal of Emerging Technology and Advanced Engineering. - 2250-2459. ; 3:12, s. 65-69
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Tidskriftsartikel (refereegranskat)abstract
- Tailings are artificial granular materials that behave different as compared to natural soil of equal grain sizes. Tailings particle sizes, shapes, gradation and mechanical behavior may influence the performance of tailings dams. Hence it is essential to understand the tailings materials in depth. This article describes present studies being carried out on Aitik tailings. Basic tailings characteristics including specific gravity, phase relationships, particle sizes, particle shapes and direct shear behavior are presented in this article. The results showed that particles size decreases along depth from surface for collected sample locations. The angularity of the particles increases as the grain size decreases. Vertical height reduction was observed during shearing of samples by direct shear tests.
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| 6. |
- Bhanbhro, Riaz, 1985-, et al.
(författare)
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Effect of Particle Size On Mechanical Properties and Particle Breakage of Tailings
- 2017
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Ingår i: Canadian geotechnical journal (Print). - 0008-3674 .- 1208-6010.
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 7. |
- Bhanbhro, Riaz, et al.
(författare)
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Evaluation Of Primary And Secondary Deformations and Particle Breakage of Tailings
- 2015
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Ingår i: From Fundamentals to Applications in Geotechnics. - : IOS Press. - 9781614996026 - 9781614996033 ; , s. 2481-2488
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Konferensbidrag (refereegranskat)abstract
- Tailings are the waste product of mining which is left over after extraction of materials of interest. Tailings material may possess different material properties depending upon type of ore and method of concentration. Sometimes the tailings material itself is used in construction of tailings dams and tailings dams are constructed to withstand for long times. A tailing dam can be exposed to settlements due to incremental load as these dams are raised in stages. Increasing load with time may also lead to particle breakage. This article presents the results from oedometer tests conducted on tailings materials. The study includes the stress-deformation behavior and particle breakage of tailings material of different gradations upon application of incremental loads in oedometer tests. The samples were collected from different sections of tailings dam from Sweden. Remolded samples were manufactured in laboratory as four batches of particle sizes i.e. 1-0.5 mm, 0.5-0.25mm, 0.25-0.125mm and 0.125-0.063mm. The results are analyzed from tested samples at different stress levels and compared with different particle sizes. The breakage of particles of each batch is analyzed by sieving the specimens after oedometer tests. The results are evaluated in terms of primary and secondary deformations. The primary and secondary deformations are also compared with different particle sized specimens.
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| 8. |
- Bhanbhro, Riaz, et al.
(författare)
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Mechanical Behavior of Uniformed Tailings Material in Triaxial Tests
- 2017
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Ingår i: Electronic Journal of Geotechnical Engineering. - : Mete Öner. - 1089-3032. ; 22:06, s. 1717-1730
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Tidskriftsartikel (refereegranskat)abstract
- Tailings dams are raised with time depending upon rate of generation of waste. A tailings dam can contain different particle sized materials within its dam body. The newly raised embankment in a tailings dam can be considered as vertical load being applied on subsequent layer. The applied loads can cause deformations and breakage of particles. The particle breakage can then lead to a skeleton with new particle size particles and hence can lead to new material properties. This paper provides the results from triaxial tests conducted on uniformed particle sizes as, 0.5mm-0.25mm, 0.25mm-0.125mm and 0.125mm-0.063mm. The tests are performed at various effective radial stresses. The results are evaluated and compared with each particle size. The results include stress-strain and volumetric behavior during shearing, the effective stress ratio and stress-dilatancy plot. The friction angles are also evaluated and compared with different particle sized specimens. It was found that effective stress ratios were slightly higher when tests were performed at lower confining stresses and vice versa. It was also observed that particle size did not show any effect of friction angles.
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| 9. |
- Bhanbhro, Riaz, et al.
(författare)
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Mechanical Properties and Particle Breakage of Uniform-Sized Tailings Material
- 2021
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Ingår i: Journal of materials in civil engineering. - Luleå : American Society of Civil Engineers (ASCE). - 0899-1561 .- 1943-5533. ; 33:3
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Tidskriftsartikel (refereegranskat)abstract
- Tailings dam disasters are reported almost every year and are triggered by mechanisms, such as overtopping, piping, and others.The failures due to inadequate management cannot be neglected as well. These dams are constructed mostly in a step-by-step constructionmethod that leads to a continuously changing state of vertical loads during construction and may lead to particle breakage and changes instrength. Therefore, a layer of tailings dam today may not be the same tomorrow during the construction phase. To study the effects ofdifferent loads on particle breakage and strength, direct shear tests were performed on remolded tailings samples that were separated intodifferent particle sizes. The tests were performed using different normal stresses that ranged from 50 to 500 kPa. The results indicate that finertailings exhibited slightly more shear resistance than that of coarser tailings irrespective of the deposition method. For normally depositedspecimen, the dilatant and contractant behavior in vertical height was observed when the normal effective stress was less than 300 kPa andgreater than 300 kPa, respectively. Under the vertical deposition method, the finer tailings showed contractant height behavior when subjectedto a normal effective stress of 300 kPa. The friction angle and the cohesion of vertically deposited specimens were slightly higher and slightlylower, respectively, than that of normally deposited ones. The breakage of tailings particles was observed to be proportional to the particle sizeof the tailings.
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| 10. |
- Bhanbhro, Riaz, et al.
(författare)
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Mechanical Properties of Soft Tailings from a Swedish Tailings Impoundment : Results from Direct Shear Tests
- 2014
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Ingår i: Electronic Journal of Geotechnical Engineering. - 1089-3032. ; 19:Z, s. 9023-9039
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Tidskriftsartikel (refereegranskat)abstract
- The shear strength of tailings can vary depending upon the type of ore and method of construction. Tailings dams may possess loose layers in subsequent layers, which may have low shear strength. Since the tailings dams are made-up to last for longer times, the strength parameters and material behaviors are essential to understand, especially potential for static liquefaction in loose layers. This article presents the results from direct shear tests performed on samples from loose layer of a tailings dam. Both drained and undrained tests are carried out. The results indicated the strain hardening behavior in tailings material which indicates loose condition. The shear strength was found to be relatively low as compared to typical values of tailings in literature. A contractant volume behavior was observed for all the tests. During shear tests the vertical height reductions in samples were observed. These changes were significantly increased after peak shear followed by slight increment in pore pressure along shearing angle. The reasons for these height changes are not fully known, but may be a rearrangement in skeleton or breakage of particles during shear which needs further investigative studies.
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| 11. |
- Bhanbhro, Riaz, et al.
(författare)
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Mechanical Properties of Soft Tailings from different Depths of a Swedish Tailings Dam : Results from Triaxial tests
- 2020
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Ingår i: Scientia Iranica. International Journal of Science and Technology. - Tehran : Sharif University of Technology, Scientia Iranica. - 1026-3098 .- 2345-3605. ; 27:3, s. 1066-1074
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Tidskriftsartikel (refereegranskat)abstract
- Construction of tailings dams is done in stages by raising it layer by layer depending on production rate of a mine. These layered dams may possess different strengths and materials properties in each layer i.e. strength parameters, behavior with loading. Tailings dams may have loose layers in subsequent layers, which upon further loading may be susceptible to stability issues. Identification of material properties and behavior is important to know for safety of dam with further raising and long term perspective modeling. This paper presents the results from drained Triaxial compression tests conducted on samples collected from loose layers, from different vertical depths of a tailings dam. The results indicated that depth did not show much influence on strength parameters determined by drained triaxial tests. The different confining pressures influenced the strain-stress behavior, high confining pressures stress-strain curve showed tendency to formulate straighten line of stress-strain curve, with contractant volume behavior along axial strains. The influence of void ratio on effective stress ratio was observed.
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| 12. |
- Bonath, Victoria, et al.
(författare)
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Properties of ice from first-year ridges in the Barents Sea and Fram Strait
- 2019
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Ingår i: Cold Regions Science and Technology. - : Elsevier. - 0165-232X .- 1872-7441. ; 168
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 13. |
- Dagli, Deniz, 1986-
(författare)
-
Laboratory Investigations of Frost Action Mechanisms in Soils
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Phase change of the water in the soil skeleton under cold climate conditions (also known as frost action in soils) affects soil properties and can be responsible for serious alterations in a soil body; causing damages (due to the volumetric expansion known as frost heave) to structures on or below the ground surface such as foundations, roads, railways, retaining walls and pipelines, etc. In order to improve the current design methods for roads against frost action, the Swedish Transport Administration (Trafikverket) has initiated a research program. The main goals of the program are to revise the existing frost heave estimation methods and improve the frost susceptibility classification system for subgrade soils.Literature was reviewed to gather the details of different freezing test equipment around the world and to identify common trends and practices for laboratory freezing tests. Based on the literature review and the collaboration with the University of Oulu, Finland an experimental apparatus was assembled for studying frost action in the laboratory. A detailed description of the experimental apparatus is given. Top to down freezing of specimens (of 10cm height and diameter) can be monitored while keeping track of water intake, vertical displacements (heave) and the temperature profile within the sample. Loads can be applied at the top of the sample to study the effects of overburden. Moreover, the test setup was modified with a camera system to have the option of recording the experiments.Disturbed samples of two different soil types were tested. Experiments with fixed and varying temperature boundary conditions were conducted to assess the validity of the assumptions for the frost heave estimation methods currently in use in Sweden. To this end, a qualitative relationship between frost heave and heat extraction rates based on theoretical equations was established. It was shown that there is a significant difference between the preliminary findings of the experimental work and the current system being used in Sweden to quantify heave.Image analysis techniques were used on two experiments that were recorded by the camera system. Image recording and correlation analyses provided detailed information about frost front penetration and ice lens formation(s) under varying temperature boundary conditions. Thawing has also been regarded in further studies. Results of the image analyses were compared to readings from conventional displacement measurements during the same test. Significant agreement between the results of image analyses and displacement measurements has been found. Image analysis was shown to be a viable method in further understanding of frost heave mechanisms.Shortcomings and disadvantages of utilizing the theoretical equations as well as the image analysis techniques were discussed. Potential remedies for overcoming the drawbacks associated with each approach are suggested. The work is concluded by discussing the potential improvements, planned upgrades (addition of pore pressure transducers) and the future experiments to be conducted.
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| 14. |
- Dagli, Deniz, et al.
(författare)
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Theoretical Analysis of the Relationship between Heave and Net Heat Extraction Rates Based on Freezing Experiments
- 2016
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Ingår i: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM. ; , s. 411-421
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Konferensbidrag (refereegranskat)abstract
- In order to improve the current design of roads against frost action, the Swedish Transport Administration (Trafikverket) has initiated a research programme. The main goals of the research are to revise the existing frost design models and the frost susceptibility classification system for subgrade soils.A qualitative theoretical analysis to establish a relationship between frost heave and net heat extraction rates based on experimental data has been done. Experiments were carried on disturbed (hand compacted), saturated samples of same type of soil without any overburden. Several different cold end temperatures were applied to create different boundary conditions to make a more detailed analysis.Results were analysed and compared to those of other researchers while pointing out the similarities and differences. Potential reasons for these differences have been identified. Based on the findings of the experimental work, suggestions for improvements are given for future testing. Some preliminary results providing hints for the relationship between segregational heave and net heat extraction rates were obtained. At the end it was shown that there exists a significant difference between the findings of the experimental work and the current system being used in Sweden in order to quantify heave.
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| 15. |
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| 16. |
- Edeskär, Tommy
(författare)
-
Deformationer i undergrund : Litteratursammanställning och analys
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det är troligt att tyngre bruttovikter kommer att tillåtas på åtminstone delar av vägnätet och andelen dispenstrafik har ökat. I denna rapport har en kartläggning över effekter av tung trafik och axelgrupper har på undergrunden. Utifrån litteraturgenomgången kan man dra slutsatsen att det ur ett vägnedbrytningsperspektiv är bättre, för samma bruttovikt, att fördela lasten på fler axlar. För belastningen i beläggningen är det i allmänhet bättre att ha lasten fördelad på flera axlar i axelgruppen. För undergrunden är det inte självklart så. Det finns en rad faktorer som verkar för ökade permanenta deformationer när lasten fördelas på axelgrupper med flera axlar genom olika effekter av amverkan mellan belastningspunkterna längre ner i konstruktionen.För att minska de permanenta deformationerna i undergrunden är det önskvärt att maximera avståndet mellan belastningspunkterna, öka lastspridningen och minska vattenkvoten i undergrundsmaterialet. Lastspridningen kan ökas genom förstärkning av överbyggnad kvalitetsmässigt eller ökad tjockleken på verbyggnaden. Dränering är den andra insatsen som kan genomföras för att minska de permanenta deformationerna. Laboratoriestudier visar att packning på den torra sidan om optimal vattenkvot bestämd genom Proctorförsök ger mindre permanenta deformationer vid cyklisk belastning. Det bör utredas närmare med tanke på att gängse praxis i Sverige är att packa med vattenöverskott eftersom det är gynnsamt för att nå optimal vattenkvot.
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| 17. |
- Edeskär, Tommy, et al.
(författare)
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Grundläggning av vindkraftverk med hänsyn till tjäle
- 2010
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Ingår i: Bygg och Teknik. - 0281-658X .- 2002-8350. ; 102:1, s. 68-73
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- På grund av den snabba utbyggnaden av vindkraftverk är erfarenheten från byggande i kallt klimat för dessa konstruktioner begränsad. Den forskning som bedrivs idag är mestadels inriktad mot vindkraftens miljöpåverkan samt frågor för att underlätta utbyggnaden och förbättra kostnadseffektiviteten, Statens energimyndighet (2008). Utbyggnad av vindkraftverk i extrema miljöer skapar nya frågor som bör utredas för att säkerställa verkens kvalitet i ett långtidsperspektiv. I denna artikel vill vi belysa frågan om tjäle och hur den är kopplad till grundläggning av vindkraftverk.
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| 18. |
- Edeskär, Tommy, et al.
(författare)
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Grundvattensänkning i morän
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det är vanligt att utförandet av grundvattenavsänkningar i moräner vid grundläggning av bro under torra förhållanden skiljer sig från beskrivningen i bygghandlingen. Det beror på att angivna metoder ofta inte är genomförbara i praktiken. Det innebär att utfallet från projekteringen inte är det önskade. Hur entreprenörerna beaktar projekteringsunderlaget i anbudet har stor inverkan på anbudsumman och därmed tilldelning. Avstegen från bygghandlingen resulterar i stora belopp för ändringar och tillägg under byggandet.Det finns metoder som används idag i stor utsträckning som inte är beskrivna som visat sig fungera relativt väl i praktiken som etappvis zonschakt med återfyll. Det är dock inte utrett under vilka förutsättningar som för vilka moräner, relativa skillnader i vattentryck och tids för utförandemomentet, metoden fungerar.Det bör övervägas att formulera funktionskrav till grundvattenavsänkning istället för strikta krav på grundvattennivåer i relation till schaktbotten eftersom det skulle rikta fokus mot syftet med kraven. Det skulle verka som stöd för både projektören, som behöver ta fram ett underlag för att säkerställa funktionen, och för entreprenören om avsteg från bygghandlingen av byggtekniska skäl.Det bör arbetas fram en revidering och komplettering av anvisningar förgrundvattenavsänkning inom branschen som inkluderar blandkorniga jordar som moräner, täcker de metoder som används idag, berör projektering och analys av grundvattensänkning och funktionskrav för utförande. Trafikverket bör överväga att inkludera dessa krav i sina tekniska styrdokument.
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| 19. |
- Edeskär, Tommy
(författare)
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Gummiklipp som konstruktionsmaterial i mark- och anläggningstekniska tillämpningar
- 2004
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I och med EG:s avfallsdirektiv från 1999 är det förbjudet att deponera hela däck från och med 2003 och förbjudet att deponera fragmenterade däck (gummiklipp) från och med 2006. Lagstiftningen syftar till ökad återanvändning eller återvinning av uttjänta däck. I Nordamerika, där liknande lagstiftning finns, har hela och fragmenterade däck använts i 30 år i vägbyggnadssammanhang som bland annat tjälisolerings- och lättfyllnadsmaterial. Syftet med detta licentiatarbete är att samla ihop och värdera den idag tillgängliga kunskapen om gummiklipps tekniska och miljömässiga egenskaper samt skaffa praktisk erfarenhet av att använda materialet i mark- och anläggningstekniska tillämpningar. Med gummiklipp avses fragmenterade däck där de enskilda bitarna varierar från ca. 30×30 mm2 till ca. 100×300 mm2. De övergripande målen med detta licentiatarbete är att: a) Identifiera, analysera och presentera den idag tillgängliga kunskapen om gummiklipps tekniska och miljömässiga egenskaper kopplat till mark- och anläggningstekniska tillämpningar. b) Genom egna fält- och laboratorieförsök skaffa praktisk erfarenhet av att använda materialet i vägkonstruktioner. c) Ge rekommendationer angående användande av materialet i mark- och anläggningstekniska tillämpningar. En vägsträcka med gummiklipp som skyddslager har byggts och utvärderats. Utrustning har installerats i vägkonstruktionerna för mätning av temperaturer, tjälfronten, sättningar och lakvatten. Konstruktionernas styvhet har bestämts genom fallviktsmätning. Tekniska egenskaper och erhållet lakvatten har jämförts mellan provsträckor och referenssträckan. Syftet med byggandet av provsträckan med gummiklipp som skyddslager är att: a) Erhålla kunskaper om att bygga med materialet. b) Studera funktionen av materialet ur tjälisoleringssynpunkt. c) Studera hur överbyggnaden ska dimensioneras för att kompensera för elasticiteten och styvheten i materialet. Målet med teststräckan är att kunna genomföra mätningar och utvärdering av sättningar av gummiklippslagret, temperaturer och tjälgränsen i vägkonstruktionen, konstruktionens styvhet (bärförmåga) och lakvatten från konstruktionen. Litteraturstudien visar att de karakteristiska egenskaperna för gummiklipp, i jämförelse med friktionsjord, är att materialet är lätt (låg densitet), elastiskt, dränerande och värmeisolerande. Gummiklipp är ett relativt kompressibelt material och många tekniska egenskaper beror av aktuell belastning. Materialet blir styvare med ökad belastning. De ämnesgrupper hos gummiklipp som främst är undersökta ur miljösynpunkt är metaller, PAH och i viss mån fenoler. I en anläggningsteknisk tillämpning är det normalt vattenburna föroreningar som är av intresse för vilken miljöpåverkan materialet kan ha på omgivningen. Lakförsök visar att metaller lakar ut från däcklipp, främst järn, koppar, mangan och zink. Metalläckaget är av samma storleksordning som för bergmaterial. Av studerade organiska föreningar lakar PAH och fenoler ut, i låga koncentrationer. Toxikologiska studier visar att lakvatten från däckmaterial har påvisbar negativ effekt på organismer. Färskt däckmaterial uppvisar större negativ respons på organismer än äldre material. Vägen med gummiklipp i skyddslager byggdes under perioden 2002-2003. Dimensioneringsarbetet med provsträckan visade att den uppskattade livslängden på konstruktionen inte påverkades nämnvärt av att styvhetsmodulen för skyddslagret varierades inom intervallet 0,25-2,0 MPa. Gummiklipp kan hanteras med konventionell utrustning som används vid vägbyggande. I vissa avseenden är gummiklipp mer lätthanterligt än konventionella vägbyggnadsmaterial som bergkross och friktionsjord, exempelvis håller materialet ihop bättre. Utvärderingen av vägkonstruktionen fram till färdigställandet av vägen visade att: a) Den utvärderade bärförmågan hos gummiklippslagret var lägre än förväntat. b) Den primära kompressionen av gummiklippet skilde mycket i storlek mellan de två delsträckorna med olika material i förstärkningslagret. c) Gummiklipp har en tjälisolerande förmåga. d) Gummiklippen lakar ut små mängder metaller och PAH. PAH-halterna var något högre än förväntat. Den färdigställda vägkonstruktionen kommer framledes att utvärderas fortlöpande dels för att jämföra dimensioneringsresultaten med verkliga konstruktionens egenskaper avseende bärförmåga och livslängd, och dels för att följa upp deformationer och tjälisoleringsförmåga samt bestämma lakvattnets sammansättning. Utifrån kunskapsnivån avseende de tekniska parametrarna som redovisats i denna avhandling kan tillämpningar pekas ut där kunskapsläget är tillräckligt för att rent tekniskt kunna använda materialet och tillämpningar där forskningsbehovet är större. Tillämpningar där tillräcklig kunskap avseende tekniska egenskaper idag kan anses finnas är bankfyllningar, dräneringslager, tjälisolering och motfyllnad. De tekniska begränsningarna som idag finns när det gäller användning av gummiklipp rör främst de elastiska egenskaperna i materialet, främst avseende styvhet och kompressibilitet. Miljöaspekten måste beaktas vid användning av gummiklipp. Vid känsliga recipienter och där avrinningsvatten kan ansamlas i små volymer kan materialet i extremfallet innebära en negativ påverkan. Placerat i applikationer där perkolationen är liten och kontakttiden mellan vatten och gummiklipp är kort bör materialet inte innebära mer påverkan än andra material. Uppföljningsstudier av provobjekt där gummiklipp använts som skyddslager i vägar och bankfyllnader visar att metaller och organiska ämnen lakar ut i låga koncentrationer från konstruktionerna.
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| 20. |
- Edeskär, Tommy
(författare)
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Gummiklipp som skyddslager i en vägkonstruktion i ett fullskaleprojekt
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Tyre shreds have been used as construction material in foundation engineering applications about 30 years, mainly in North America. Tyre shreds have interesting technical properties for foundation engineering applications such as low density, high draining capacity, and thermal isolation capability. In Europe the experiences are few in using tyre shreds in foundation engineering work. In this project tyre shreds have been used as capping layer for thermal insulation purposes in a test section of the national road 686 outside the city of Boden in northern Sweden. The road was reconstructed and paved in order to increase the bearing capacity. A 600 mm thick tyre shred layer was used as thermal insulation underlaying the sub-base material. The test site is divided into three test sections. In test section P1 crushed rock is used as sub-base material and in test section P2 air blast furnace slag as sub-base material. The third test section is used as a reference and consists of crushed rock as sub-base material without underlaying capping layer. The main objectives of the test site are to gain experience in using tyre shreds as a construction material, study the capacity of thermal insulation of the material and to study how to design the superstructure when using tyre shreds using the Swedish design practise for flexible pavement.
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| 21. |
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| 22. |
- Edeskär, Tommy, et al.
(författare)
-
Höghastighetsspår i Sverige : på bank
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det ska byggas höghastighetståg i Sverige, men det finns osäkerheter kring vilken metod som är bäst lämpad för de svenska förutsättningarna. Det kalla klimatet utgör ett frågetecken. Det är även okänt hur sättningar kan komma att utvecklas under konstruktionen, det finns erfarenheter från övriga världen att detta kan utgöra ett problem, särskilt för metoden med spårplattor.De två metoder att konstruera höghastighetsjärnväg som presenteras i rapporten är ballastburna spår och spårplattor. Ballastburna spår är vanliga i Sverige för konventionell hastighet, det finns gott om erfarenhet kring byggande och underhåll av denna typ av spår. Det är en billigare metod än spårplattor och det är lätt att justera spårläget då spåret är i bruk. Spårplattor däremot sägs vara ”underhållsfria”, vilket innebär att de byggs så att minimalt underhåll ska krävas. Om det då skulle uppstå deformationer under spårplattan är det arbetsamt att korrigera detta, därför ställs kravet att undergrunden ska vara ” i princip sättningsfri”. Försök att definiera vad detta betyder är att ställa mätbara krav på undergrundsmaterialet eller sätta tillåtna gränser för sättningen. Att ställa upp krav på tillåten deformation låter rimligt men det är svårt att dimensionera för eftersom det inte finns metoder för att prognostisera dessa deformationer. Därför har det i denna rapport undersökts hur permanenta deformationer för ett grovkornigt material (som är den typ av material som kanutgöra fyllningsmaterial) beror av olika parametrar. De permanenta deformationerna drivs på av de yttre lasterna och därför beror de av spänningsnivån både för statiska och repeterade belastningar. Ytterligare parametrar som inverkar är packningen, bergartens hållfasthet, kornens storlek, ytråhet och form. Packningen inverkar genom att tätare material har fler kontaktpunkter och lägre porositet, vilket leder till mindre deformation. Om ett korn är stort är sannolikheten större att det finns svagheter och andra brister än om kornet varit mindre. Större korn har därför lägre hållfasthet samt att större korn har färre kornkontakter mellan varandra vilket gör kontaktkrafterna större, detta leder till större deformationer. Kantiga korn (krossat material) har högrefastlåsningsmöjligheter mellan varandra än rundade korn (naturligt material, naturgrus, natursand). Frys-/töcykler har också inverkan på sättningarna genom att ett grovkornigt material omlagras vid frysning och tining, något som generellt gör materialet lösare och mer sannolikt att deformera.För att finna samband mellan olika parametrar och den permanenta deformationen används olika försöksmetoder, främst triaxialförsök. Vid studier av litteratur där triaxialförsök har genomförts kunde ses att det var vanligt att skala ned storleken på materialet för att grövre material kräver större försöksutrustning. Undersökningar har visat att kornstorleken påverkarskjuvhållfastheten och då ger inte ett nedskalat material ett representativt resultat. För att undersöka ett mycket grovkornigt materials egenskaper krävs att materialet testas i rätt storlek. Fortsatta studier beskrivs där ett mycket grovkornigt materials egenskaper undersöks med laborativa försök.
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| 23. |
- Edeskär, Tommy, et al.
(författare)
-
Leaching of phenol from tire shreds in a noise barrier
- 2004
-
Ingår i: Sustainable waste management and recycling. - London : Thomas Telford Ltd. - 0727732870 ; , s. 251-260
-
Konferensbidrag (refereegranskat)abstract
- As part of the Norwegian Roads Recycled Materials R&D Program (www.gjenbruksprosjektet.net), a large light fill noise barrier has been constructed along highway E6. The structure utilized 25% of all tyres that were collected in Norway in 2002. Four monitoring stations are used to sample leachate from drainage that enter local recipient. The leaching of anti-oxidizing compounds from tyre shreds is of concern for Norwegian environmental authorities. In national pilot projects where tyre shreds are used as a light fill material special precaution is taken not to harm the surface water recipients. A five-year monitoring program will document relative effect from different sources and the risk of environmental harm will be evaluated. Ongoing pilot projects indicate that leaching of nonyl-, octyl- or bisphenol from tyre shreds induces no environmental risk if applied under given design conditions. The way of application of recycled material will have an impact on long-term risk and the possibility of reuse or recycling of tyre shreds.
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| 24. |
- Edeskär, Tommy, et al.
(författare)
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Longitude profiling as a tool for evaluation of frost actions active pavement section
- 2017
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Ingår i: Bearing Capacity of Roads, Railways and Airfields. - London : CRC Press. ; , s. 2095-2102
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Konferensbidrag (refereegranskat)abstract
- In seasonal frost regions frost action is a major impact factor on pavement deterioration. Normally frost damage evaluation has been carried out by visual inspection in late spring in order to separate frost action related damages from other pavement damages. The drawback of this methodology is the labour cost, subjective judgement of damages by the personnel and work safety. This approach is not suited for monitoring the condition of on a road net level. Laser scanning has been used for decades as an efficient tool to monitor the rutting development on the road net. The monitoring technique requires a snow and ice free surface to get accurate results. Thus has the use of this technology been limited in the winter seasons. In a few regions longitude profiling measurements have been introduced during for quantify winter conditions. More development is needed in the field of evaluation and techniques to relate the measurements to frost related processes. In this study has data from longitude profiling in four monitoring lines in from summer and late spring been analysed for a number of road sections. Spatial data analysis has been applied to match the acquired measurements in between the monitoring directions along the road and the different seasons. The difference in roughness between the seasons has been used as a measure to identify and qualitative grade the amount of frost action. The methodology and its applicability as an objective frost damage classification tool are discussed.
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| 25. |
- Edeskär, Tommy, et al.
(författare)
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Numerical analysis of frost penetration around footings of power mills in subarctic conditions
- 2009
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Ingår i: Proceedings of the 20th International Conference on Port and Ocean Engineering under Arctic Conditions.
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Konferensbidrag (refereegranskat)abstract
- The potential for establishing wind power farms in the subarctic areas is high due to the combination of large available areas and few conflicting interests. In subarctic climate frost and thaw are major principal design aspects. In foundation work the major impact of frost action is at the outer peripheries of the foundation. Therefore most analysis work and prevention actions such as insulation around the foundation are concentrated to this part of the structure. The gravity foundations of wind power plants are often constructed as a reinforced concrete monolite. In the centre of the footing a steel cage is attached for anchoring the wind mill tower. This steel cage ends close to the sub-grade and can due to considerably higher thermal conductivity, compared to the concrete structure, transport a lot more heat. By FEM analysis, the frost penetration around, and under two typical wind-power foundations have been analyzed for different climate conditions in Sweden. In addition, different soil types have also been used. The result shows that the frost penetration in the centre of the foundation needs to be considered. Further it is shown that it is larger in the centre than compared to the periphery.
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| 26. |
- Edeskär, Tommy, et al.
(författare)
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Reparationsinjektering av dammar och undergrund : Strategi för forskning och utveckling
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Swedish hydropower dams are aging and the main focus within the hydropower industry is to preserve the functionality of the dams and to adapt to changing conditions and increased safety demands. In general it is more complicated to repair or upgrade a present dam compared to construct a new dam. To completely replace an old dam with a new is in general unrealistic and thus it is important to have access to available and reliable methods for repair and upgrade of existing dams.Today, there is a range of grouting methods that are possible to use for repair purposes on existing dams and their foundations that has been tested internationally or in Sweden. The following methods have been identified for remedial work on dams: compaction grouting, permeation grouting, intrusion grouting and slurry trench. Of these methods, permeation grouting is identified as the most promising method for remedial purposes of a typical Swedish dam and there are several interesting research and development issues connected to this method of importance for the Swedish hydropower industry.Permeation grouting is generally practiced by the use of a combination of grouts, individually adapted to cracks of different sizes. There are several grouts available on the market, but for several of these can the long term performance be doubtful from environmental concerns. There are some thoughs about alternative grout that are promising and that has not yet been tested in Sweden such as e.g. Silica Sol in solution activated by calcium ions.There is a need to develop the grouting techniques and a more engineering based grouting process for dam projects. Especially the injection pressure needs to be further investigated in order to secure the performance of grouting action without endanger the safety or overall performance of the dam. Furthermore, a better control method of the grout spread is needed, where the “real time grouting control method” is recommended for further research. Grouting in flowing regimes and under water pressure are of special interest for the dam industry. Especially with respect to research regarding erosion stable grout mixes.There is today a lack of exchange of experience from previous remedial grouting projects. Historical and future remedial grouting projects are recommended to be documented within the Swedish Hydropower Center (SVC) program.
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| 27. |
- Edeskär, Tommy, et al.
(författare)
-
Statistical analysis of thaw index for thaw weakening design purposes
- 2016
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Ingår i: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM. ; , s. 1321-1327
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 28. |
- Edeskär, Tommy
(författare)
-
Technical and environmental properties of tyre shreds focusing on ground engineering applications
- 2004
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This technical report is a state-of-the-art literature review regarding tyre shreds as a construction material for published material in English, Swedish and Norwegian languages. The main focus is to present the technical and environmental properties of tyre shreds focusing on the use of the material as unbound aggregates in foundation and geotechnical engineering applications. The technical properties of tyre shreds are relatively well investigated. In general, methods for determining technical properties for soils have been used in the studies. Compared to conventional soil materials like sand and gravel, tyre shreds are considered to be a lightweight material, bulk density 500-900 kg/m3 depending on compaction and overlaying pressure. The low thermal conductivity, 0.15-0.30 W/m,K, makes the material interesting for thermal insulation. The permeability is high,about 0.01 m/s, at overlaying pressures up to at least 200 kPa. Tyre shreds is a relatively weak material, Young’s modulus is approximately 1 MPa depending on overlaying pressure. Poisson’s ratio is typically 0.3. The stress-strain relationship is non- linear and the material becomes stiffer as the stress increases. The shear strength is high at large strains, effective cohesion intercept 0-82 kPa and effective friction angle 15–36º at 20 % strain, and low at smaller strains, effective cohesion intercept 0-12 kPa and effective friction angle 19-38º at 10 % strain. The durability of tyre shreds seems not to be a problem in applications where the material is not exposed to UV-radiation or heat. The environmental implications of using tyre shreds in ground engineering applications have here been studied by dividing the results into three different categories; chemical content, leachability and environmental response. Tyre shreds contain compounds that have a pollution potential, e.g. PAH, phenols and zinc. The leachability of most compounds is low under normal conditions in civil engineering applications, i.e. for pH 5-8 and water as a leaching agent. Ecotoxicological studies show that tyre leachate causes response in these tests. Compared to the European Unions classification for chemicals these responses are below hazardous limits. However, some other species studied are sensitive to tyre leachate. Field experiences of using tyre shreds shows, up to know, no measurable negative effects in surrounding environment. Tyre shreds have beneficial properties, e.g. low density, high hydraulic conductivity, low thermal conductivity and high shear strength at large strains. There are properties of tyre shreds which differs from soil materials like sand and gravel that must be especially considered in design, e.g. the elastic properties. There are several successful examples of use of tyre shreds in civil engineering applications, e.g. in road embankments, as thermal insulation layer, in lightweight embankments and as draining layers in landfills. There are also examples of not successful projects resulting in useful experiences in design work and limitations of the material. The environmental effects of using tyre shreds needs to be considered. Before use a site-specific evaluation is recommended where both the construction and surrounding environment are considered. Based on today’s knowledge the use of tyre shreds should be limited to above the ground-water table and, if high percolation is expected, to non-sensitive recipients where the potential accumulation of pollutants may not be a problem.
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| 29. |
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| 30. |
- Edeskär, Tommy, et al.
(författare)
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Use of scrap tyres as insulation layer in road construction
- 2007
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Ingår i: Proceedings of the 8th International Symposium on Cold region Development ISCORD 2007. - : RIL - Finnish Association of Civil Engineers.
-
Konferensbidrag (refereegranskat)abstract
- Used tyres are not allowed to be placed on landfills any more, but can be used as insulation materials with very good results. The present paper describes a study in which tyre shreds (50mm * 50 mm) were used as insulation material in a road construction. The tyre shreds had a thickness of 600 mm and were covered with 875 mm of road superstructure. The effect of the layer on frost depth and frost heave was measured during three winters. As scrap tyres are a highly elastic the bearing capacity and Young's module were measure directly on the road by the use of a falling weight deflectometer. The potential environmental impact was also studied. The scrap tyres showed a very good insulation performance, mostly due to its high porosity. Effects of frost action were not visible or recorded. The studied construction had deformation pattern of the road surface was within acceptable limits. The environmental impact was studied before the pavement was placed at the top and therefore leakage could be detected.
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| 31. |
- Edeskär, Tommy
(författare)
-
Use of tyre shreds in civil engineering applications : technical and environmental properties
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- End-of-life tyres are a disposal problem regarding the large volumes produced every year. Tyre shreds are primarily produced to reduce the transportation volumes of end-of-life tyres after collection. Within the European Union, there is a ban for landfilling tyre material in order to reduce the total landfilling volumes and to encourage recycling measures. Until recently the main disposal option has been energy recovery in industrial processes. However, legislation acts has recently been taken in the European Union to encourage recycling and recovery of end-of-life-tyres and re-use of tyre materials in construction works is listed as one disposal option.Tyre shreds possess interesting technical properties that could be beneficially used in civil engineering applications. Some characteristic properties of tyre shred materials are the low density, high elasticity, low stiffness, high drainage capacity and high thermal insulation capacity. These properties open up possibilities for utilisation of the material in an innovative manner.The overall aim of this thesis work has been to describe and evaluate tyre shreds as a civil engineering construction material from environmental and technical point of view. The thesis work has included laboratory tests and full scale field tests to investigate technical and environmental properties of tyre shreds and to investigate the tyre shred material behaviour in a real road construction. Furthermore, the state-of-the-art knowledge in the area has also been analysed and presented.In the laboratory studies technical properties focused on compaction and compression behaviour of tyre shreds have been investigated. In a field study of a built road, tyre shreds has been tested and evaluated, during four years, as lightweight fill and frost insulation material. Environmental properties of tyre shreds, mainly leaching characteristics, have been studied in laboratory tests and monitored in two full scale field tests.Based on the results in the laboratory studies a model is proposed for evaluation of stressstrain properties and prediction of compression behaviour. Recommendations for construction works and pavement design are suggested based on the road construction field study results.Conclusions regarding the studied leaching properties of tyre shreds, based on the laboratory tests and the field monitoring, are that zinc and iron are the metals mainly released and that the release of the studied organic compounds, i.e. PAH and phenols, are low. From an environmental point-of-view focus should be moved from PAH-compounds towards other compounds that are more interesting from mobility perspective and lack of knowledge. It is concluded from this thesis work that PAH is not a pollution problem in the area of use of tyre material covered by this work.Applications where tyre shreds have been successfully utilised as construction material, are e.g. as draining layers in landfills and as material in trotting tracks and paddocks. The utilisation of the material in trotting tracks and paddocks is especially interesting since the unique elasticity of the material is utilised. The potential of utilising tyre shreds in civil engineering construction is big. Since the available amounts of material is limited there is a possibility to direct the use of tyre shreds to the most favourable applications of tyre shreds and still solve the disposal problem of end-of-life tyres.
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| 32. |
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| 33. |
- Johansson, Fredrik, et al.
(författare)
-
Reparationsinjektering av dammar och undergrund : strategi för forskning och utveckling
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Svenska dammar blir allt äldre och i huvudsak fokuserar industrin på att bibehålla dammarnas funktion och anpassa dem till förändrade förutsättningar och ökade säkerhetskrav. Det är i allmänhet mer komplicerat att reparera eller uppgradera befintliga anläggningar jämfört med att bygga nya. Bygga nytt är i allmänhet orealistiskt vilket innebär att det är angeläget att det finns tillförlitliga metoder tillgängliga för att reparera och uppgradera befintliga anläggningar.Det finns en rad injekteringsmetoder som kan användas för reparation av dammar och undergrund och som prövats internationellt och i viss utsträckning även tidigare i Sverige. Följande metoder har identifierats: kompaktinjektering, permeationsinjektering, inträngningsinjektering och slitsmur. Av dessa metoder har permeationsinjektering identifierats som mest intressant för rehabilitering av medelstora svenska dammar. Inom detta område finns ett antal intressanta forsknings- och utvecklingsspår som är viktiga för branschen.Permeationsinjektering innebär vanligen en användning av en kombination av injekteringsbruk, oftast två olika, för att åtgärda sprickor av olika storlek. Det finns en rad injekteringsbruk tillgängliga men för flera kan beständigheten ifrågasättas eller bör undvikas av miljöskäl. Det finns dock alternativ som bör undersökas närmare och som inte tidigare använts i Sverige, t.ex. silica sol i lösning som aktiveras med kalcium.Vidare behöver en mer ingenjörsbaserad injekteringsmetodik utvecklas och skräddarsys för användning på dammar. Det gäller framförallt vid vilket tryck injekteringen ska utföras för att uppnå ett tillfredsställande injekteringsresultat utan att äventyra dammkonstruktionens säkerhet. Det krävs även bättre kontrollmetoder för brukets spridning under injektering, där forskning rekommenderas inom konceptet ”real time grouting method”. Injektering i strömmande förhållanden och under vattentryck bör också studeras närmare. Särskilt fokus bör läggas på att säkerställa under vilka förhållanden bruket är erosionsstabilt samt att injekteringsskärmarna uppnår de egenskaper som förväntas.Det finns idag bristande erfarenhetsåterföring i Sverige från genomförda reparationsinjekteringsprojekt. Historiska och kommande projekt bör därför dokumenteras inom SVC.
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| 34. |
- Johansson, Jens, et al.
(författare)
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Effects of external water-level fluctuations on slope stability
- 2014
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Ingår i: Electronic Journal of Geotechnical Engineering. - : Mete Öner. - 1089-3032. ; 19:K, s. 2437-2463
-
Tidskriftsartikel (refereegranskat)abstract
- There is a worldwide increasing need of land-use in costal/waterfront areas. All kinds of changes of geotechnical conditions in these areas pose potentially slope instability and jeopardized values of property and life. Soil slopes are affected by water-level fluctuations originating from as well tides and other waves, as non-natural sources such as watercourse regulation for irrigation, freshwater provision, and/or hydropower production. Due to a growing use of non-regulated energy sources (e.g. wind and solar), the need of energy balancing and storage is increasing. Also techniques such as pumped hydropower storage (PHS), which may be associated with significant water-volume changes in the reservoirs, are growing globally. This is expected to involve variations of hydropower reservoir water levels; hour to hour, day to day and/or seasonally. In this paper geotechnical effects of water-level fluctuations on slope stability are reviewed; relevant inter-disciplinary findings are presented, adventurous simplifications and/or inadvertencies are underlined, and potential improvement areas are identified. A lot of research has been carried out focused on coastal erosion; mainly aimed to investigate tide-water influence on slope-profile development, and quantification of sediment production. On the other hand, studies on effects of water-level changes on geotechnical conditions in adjacent soil structures have been predominantly concerning embankment dams. In addition, studies addressing processes in natural slopes and banks are often environmentally oriented, rather than focused on slope stability. Since also water-level rise (not only drawdown) has been shown to significantly influence slope stability, further investigation of processes of suction loss, effects of rapidly increased water pressures, and retrogressive failure development is needed. Long-term views are often missing; analyses tend to involve few rise-drawdown cycles, soil materials are deficiently described, and limited attention is put on constitutive models used. Reliable integration of seepage effects on soil-property changing requires consideration of as well acute effects as long-term changes. Therefore, proper consideration of internal erosion is central. Given the critical relationship between pore pressure, soil strength, and soil-deformation, analyses have to be performed using robust simulation approaches. The terms “simplicity” and “applicability”—promoting use of limit-equilibrium methods—should more often be set in relation to accuracy and robustness provided by use of methods considering also deformations.
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| 35. |
- Johansson, Jens, et al.
(författare)
-
Modelling approaches considering impacts of water-level fluctuations on slope stability
- 2014
-
Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scienpress Ltd. - 1792-9040 .- 1792-9660. ; 4:4, s. 17-34
-
Tidskriftsartikel (refereegranskat)abstract
- Waterfront slopes are affected by water-level fluctuations originating from as well natural sources (e.g. tides and wind waves), as non-natural sources such as watercourse regulation involving daily or hourly recurring water-level fluctuations. Potentially instable slopes in populated areas means risks for as well property as human lives. In this study, three different approaches used for hydro-mechanical coupling in FEM-modelling of slope stability, have been evaluated. A fictive slope consisting of a till-like soil material has been modeled to be exposed to a series of water-level fluctuation cycles (WLFC’s). Modelling based on assuming fully saturated conditions, and with computations of flow and deformations separately run, has been put against two approaches being more sophisticated, with unsaturated-soil behavior considered and with computations of pore-pressures and deformations simultaneously run. Development of stability, vertical displacements, pore pressures, flow, and model-parameter influence, has been investigated for an increased number of WLFC’s. It was found that more advanced approaches did allow for capturing larger variations of flow and pore pressures. Classical modelling resulted in smaller vertical displacements, and smoother development of pore-pressure and flow. Flow patterns, changes of soil density (linked to volume changes governed by suction fluctuations), and changes of hydraulic conductivity, are all factors governing as well water-transport (e.g. efficiency of dissipation of excess pore pressures) as soil-material transport (i.e. susceptibility to internal erosion to be initiated and/or continued). Therefore, the results shown underline potential strengths of sophisticated modelling. Parameter influence was shown to change during water-level cycling.
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| 36. |
- Lintzén, Nina, et al.
(författare)
-
Study on basic material properties of artificial snow
- 2012
-
Ingår i: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM. - Copenhagen : Danish Geotechnical Society. - 9788789833279
-
Konferensbidrag (refereegranskat)abstract
- For buildings and constructions made by snow, like for example the ICEHOTEL in Jukkasjärvi, generally artificial snow is used. Both for safety reasons and for design purposes it is hence of importance to understand the material behaviour of artificial snow. Many buildings and structures made by snow and ice are constructed using knowledge obtained by experience.When subjected to a load snow undergoes an immediate elastic deformation and a time-dependent irreversible deformation, known as snow creep, which constitutes the considerably highest part of the total deformation. The magnitude of the snow creep deformation is the dominating deformation mechanism for snow structures but it is poorly investigated and not well understood.To study material parameters and mechanical behaviour of artificial snow unconfined compression test and deformation tests to observe the creep behaviour have been performed. Results from experimental tests have been analyzed and compared with theoretical calculations and finite element simulations. The density and viscosity have shown to be important parameters for the deformation behaviour and will have a direct influence on the creep rate. The investigation indicates that the artificial snow used for the tests have higher density, compression strength and creep strength compared to natural snow used in other studies.
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| 37. |
- Lintzén, Nina, et al.
(författare)
-
Uniaxial Strength and Deformation Properties of Machine-Made Snow
- 2015
-
Ingår i: Journal of cold regions engineering. - 0887-381X .- 1943-5495. ; 29:4
-
Tidskriftsartikel (refereegranskat)abstract
- Snow as a construction material has been used for centuries, with igloos among the first examples. Each winter, snow and ice villages, buildings, and artwork are built in many places around the world. Machine-made snow manufactured by snow guns is commonly used for constructions made of snow. However, only a few basic studies on machine-made snow have been published. Knowledge based on experience and studies on natural snow constitute the basis for constructions made using snow and ice. Through material tests on machine-made snow used for construction, data on important physical and mechanical properties have been established that aim to improve and optimize safe constructions made from snow. Strength tests have been performed using two different qualities of machine-made snow. Specimens used for testing were cut out from one block of snow that had a coarse-grained structure with clusters of ice in the snow and from one block of snow with a fine-grained and homogeneous structure. The density for each tested snow sample was measured and strength tests were performed at different deformation rates to investigate the relationship between mechanical properties and deformation rate or strain rate. The load response curves achieved from the strength tests were used to evaluate compressive strength, Young’s modulus, and the residual modulus. The results show that compressive strength increases with increasing density. Increasing compressive strength with an increasing strain rate was also observed for fine-grained snow quality specimens, whereas no similar tendency was observed for coarse-grained snow. The residual modulus increased with an increasing strain rate up to a certain critical value for the fine-grained machine-made snow specimens. Regression analysis was used to investigate whether any dependence was observed between the calculated mechanical properties; no further relationship between the mechanical and the physical properties was noticed
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| 38. |
- Mácsik, Josef, et al.
(författare)
-
Kontroll och uppföljning av askvägar : Kommunikation och acceptans
- 2011
-
Rapport (refereegranskat)abstract
- Stabilisering av obundna lager i vägöverbyggnader är en tekniskt, ekonomiskt och miljömässigt lovande teknik. Det saknas en svensk vägledning för metoderna stabilisering av terrass och stabilisering av obundet lager, vilket leder till att tekniken används sparsamt. Metoden bedöms trots detta ha stor potential i och med att bärigheten är en allt viktigare fråga. Stabilisering med cement, kalk och Merit, som används traditionellt som bindemedel, är en förhållandevis dyr metod. Goda geotekniska egenskaper och lägre bindemedelskostnad är de största incitamenten till att använda flygaska som bindemedelkomponent. En viktig drivkraft hos producenter av flygaska är att hitta avsättning för stora volymer. Flygaska nyttjas främst som lager (monolit) och vid stabilisering av bär-/ förstärkningslager på industriytor och grusvägar. Kunskapen om de stabiliserade lagrens beständighet är begränsad till en förhållandevis korta tid. Projektets mål var att visa vad som bör mätas/redovisas för att visa att ett stabiliserat lager i en vägkonstruktion ger högre bärighet och längre livslängd. Målet var att ge stöd för att använda tekniken att stabilisera obundna lager och för att nyttja flygaskor som bindemedel. Målgruppen var nyckelaktörer som väghållare, utförare och miljömyndigheter. Inom projektets ramar har erfarenheter från fyra pilotprojekt, Rv90, Hallstavik, Lungviksverket, och Dåvamyrans industripark, summerats vad gäller bärförmåga och/eller miljötekniska egenskaper. Det genomfördes också en intervjustudie med nyckelaktörer för att utreda möjligheter och hinder för stabilisering med flygaska som bindemedel. Projektets resultat visar att de projekt som genomförts under senare tid med flygaskor som bindemedel har utförts enligt befintlig vägledning för ”Flygaska i mark och vägbyggnad”. Intervjuresultatet visar samtidigt att byggkontroll är ett viktigt instrument för att erhålla god vägkvalitet. Packningskontroll och kontroll av vattenkvot eller TS-halt är viktiga parametrar för att säkra vägens bärförmåga och goda tjälegenskaper. Det saknas en svensk vägledning för stabilisering av terrass och obundna lager, vilket lyftes som ett hinder för användning av flygaska som bindemedel. Exempelvis visar erfarenheter från vägsträckan utanför Hallstavik att det stabiliserade obundna lagret är ett tätt material. Grundvattenprover som togs i grundvattenrör installerade i vägdikesområdet längs provsträckan indikerar att halterna av metaller ligger på samma nivå eller under de halter som har uppmätts i referenspunkten. Besiktning av vägens tillstånd hösten 2009 visade att den stabiliserade sträckan håller god kvalitet, medan referenssträckan är i behov av åtgärd på grund av potthål etc. Resultaten från Lungviksverket visar att infiltrerat vatten med hög organiskt innehåll kan leda till utlakning av bl.a. As från flygaskan. En sammanställning av detta arbete pekar på att det finns ett stort behov av att objekt ska dokumenteras från planering till drift. Flera demonstrationsprojekt behövs för att styrka olika oberoende aktörers erfarenheter vad gäller livslängd, ekonomi, miljö, drift och underhållskostnader. Ett av problemen idag är att en sådan sammanhållen empiri saknas. Viktiga kontrollparametrar som bör kopplas till vägens livslängd är tillståndsbedömning, mätning av ytans jämnhet, spårbildning, beläggningsskador och vägens bärighet. Projektets resultat och intervjuerna indikerar flygaskans positiva långtidsegenskaper som konstruktionsmaterial i väg. Fältarbetena i Lungviken och Dåvamyrans industripark som utfördes inom ramen för detta projekt följde vägledningen för ”Flygaska i mark och vägbyggnad”, vilket bidrog till att sprida informationen om metodiken hos aktörer, som väghållare, vägtekniker, geotekniker, askleverantörer och miljömyndigheter.
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| 39. |
- Macsik, Josef, et al.
(författare)
-
Kontroll och uppföljning av askvägar : kommunikation och acceptans
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Stabilisering av obundna lager i vägöverbyggnader är en tekniskt, ekonomiskt och miljömässigt lovande teknik. Det saknas en svensk vägledning för metoderna stabilisering av terrass och stabilisering av obundet lager, vilket leder till att tekniken används sparsamt. Metoden bedöms trots detta ha stor potential i och med att bärigheten är en allt viktigare fråga. Stabilisering med cement, kalk och Merit, som används traditionellt som bindemedel, är en förhållandevis dyr metod. Goda geotekniska egenskaper och lägre bindemedelskostnad är de största incitamenten till att använda flygaska som bindemedelkomponent. En viktig drivkraft hos producenter av flygaska är att hitta avsättning för stora volymer. Flygaska nyttjas främst som lager (monolit) och vid stabilisering av bär-/ förstärkningslager på industriytor och grusvägar. Kunskapen om de stabiliserade lagrens beständighet är begränsad till en förhållandevis korta tid.Projektets mål var att visa vad som bör mätas/redovisas för att visa att ett stabiliserat lager i en vägkonstruktion ger högre bärighet och längre livslängd. Målet var att ge stöd för att använda tekniken att stabilisera obundna lager och för att nyttja flygaskor som bindemedel. Målgruppen var nyckelaktörer som väghållare, utförare och miljömyndigheter.Inom projektets ramar har erfarenheter från fyra pilotprojekt, Rv90, Hallstavik, Lungviksverket, och Dåvamyrans industripark, summerats vad gäller bärförmåga och/eller miljötekniska egenskaper. Det genomfördes också en intervjustudie med nyckelaktörer för att utreda möjligheter och hinder för stabilisering med flygaska som bindemedel.
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| 40. |
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| 41. |
- Mácsik, Josef, et al.
(författare)
-
Utformning av skyddsskikt : Beständighet
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Sluttäckning av deponier utförs i syfte att minimera inläckage av vatten och syre till avfallet. Principen är att ”det som inte läcker in inte heller kan rinna ut”. Förutom vattentransport ska sluttäckningen bidra till att minimera utläckage av metan som bildas i deponier med organiskt avfall. Sluttäckningen ska dessutom utformas så att den ska fungera under hundratals år. Skyddsskiktets frysmotstånd är en viktig funktion som kan påverka sluttäckningskonstruktionens funktion och livslängd. Trots detta läggs idag relativt lite fokus på hur den utformas med avseende på tjäle och metanoxidation. Traditionellt består sluttäckningens skyddsskikt av en sandwichkonstruktion som inkluderar ett skydds- och växtetableringsskikt. Med genomtänkt materialval kan skyddsskiktet utformas så att det med god marginal kan skydda tätskiktet från tjäle. Målsättningen med projektet är att visa att alternativa material kan fylla en viktig funktion i skyddsskiktet med avseende på metanoxidation och frysmotstånd. I projektet jämförs konventionellt skyddsskikt bestående av morän med skyddsskikt där morän kombineras med alternativa material. Olika materials värmeledningsförmåga togs fram baserat på litteraturstudier och tidigare erfarenheter. Modellering av frysmotstånd utfördes för fem befintliga deponiers skyddsskikt. Frysmotståndet jämfördes sedan med skyddsskikt som består av morän. En moräntäckning (finjordshalt < 30 %) på 1,2 m ger inte tillräckligt frysmotstånd vid en köldmängd på ca 600°dygn. Medelköldmängd 600°dygn i ett 30-årsperspektivpå motsvarar en linje mellan Karlstad och Gävle. Genom att ersätta 0,5 m morän med kompostjord, klarar skyddsskiktet drygt 2400°dygn även om moränkvaliteten inte uppfyller kriteriet på finjordshalt på > 30 % För att uppskatta gasförlusterna genom täckskiktet samlades information om mängd deponerat avfall, uppsamling av deponigas, nedbrytningshastighet och gasbildningspotential från några deponier. Baserat på sammanställningen och en utförd litteraturstudie gjordes bedömningen att metanläckage genom skyddsskiktet till atmosfären pågår och fortsätter att pågå i flera decennier. Bedömningen är att det finns ett behov att utforma skyddsskiktskikt så att metan kan oxideras innan det når atmosfären. Modellering visar att skyddsskiktets fukthalt och en jämn porositet är viktiga egenskaper både vad gäller frysmotstånd och metanoxidationseffektiviteten. Metanoxidation bedöms inte begränsas av näringsämnen och organiskt material. Användning av alternativa material i skyddsskiktet bedöms kunna leda till tunnare skyddsskikt och att sluttäckningskostnaderna reduceras samtidigt som bättre funktion och längre livslängd på sluttäckningskonstruktionen kan uppnås. Metanoxidation i skyddsskiktet är temperaturberoende och litteraturstudier indikerar att så länge temperaturen överstiger 12°C påverkas inte metanoxidationsförmågan nämnvärt Temperaturmätningar i en sluttäckningskonstruktion i Obbola, Umeå indikerar att värmen från nedbrytning av avfall i en deponin kan ge optimala temperaturförhållanden till en året runt effektiv metanoxidation i skyddsskiktet.
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| 42. |
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| 43. |
- Rodriguez, Juan, et al.
(författare)
-
Effect of vertical load on tailings particles
- 2016
-
Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 6:2, s. 115-129
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 44. |
- Rodriguez, Juan M., et al.
(författare)
-
Case of study on particle shape and friction angle on tailings
- 2013
-
Ingår i: Journal of Advanced Science and Engineering Research. - 2231-8844. ; 3:4, s. 373-387
-
Tidskriftsartikel (refereegranskat)abstract
- Tailings are crushed and milled materials result of the mining production. Tailings need to be stored in facilities, usually tailings dams, for a long time period for mainly safety and environmental protection. In order to design tailings dams in a long term perspective not only current material properties is needed but also future changes of these properties due to e.g. weathering. On a particle level the weathering will result in shape changes and decomposition. By studying the changes in shape a prognosis of changes in properties of a tailings deposit may be established.Tailings are site specific material and are not well investigated compared to natural geological materials such as soil. Tailings materials size ranges generaly from sand to silt and the particle shape by genesis or production processes. Based on laboratory tests tailings from the Aitik mine has been investigated through triaxial tests and particle shape quantification by two dimensions image analysis. The shape descriptors Aspect Ratio, Circularity, Roundness and Solidity are used in this study. These shape descriptors are evaluated based on how well these describes talings materials. The evaluated shape descriptors are used in previous published empirical relations between shape and friction angle. As reference are friction angles evaluated by triaxial tests on the material used.The results show that the particle shape is affected by the size of the aggregates. Aggregates in small fractions are more elongated and less rounded, i. e. more angular, compared to larger. Furthermore, the Aspect Ratio and Circularity seems to be the most situable quantities to describe the tailings behaviour in relation with the empirical model. The accuracy in predicting the friction angle of the tailings by previously published relations based on uniformly graded sand material are low. But the systematic underestimation of the friction angle indicates that it would be possible to establish such empirical relations based on tailings material.
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| 45. |
- Rodriguez, Juan M., et al.
(författare)
-
Particle Shape Quantities and Measurement Techniques–A Review
- 2013
-
Ingår i: Electronic Journal of Geotechnical Engineering. - : Mete Öner. - 1089-3032. ; 18/A, s. 169-198
-
Tidskriftsartikel (refereegranskat)abstract
- It has been shown in the early 20th century that particle shape has an influence on geotechnical properties. Even if this is known, there has been only minor progress in explaining the processes behind its performance and has only partly implemented in practical geotechnical analysis. This literature review covers different methods and techniques used to determine the geometrical shape of the particles. Particle shape could be classifying in three categories; sphericity - the overall particle shape and similitude with a sphere, roundness - the description of the particle’s corners and roughness - the surface texture of the particle. Thecategories are scale dependent and the major scale is to sphericity while the minor belongs to roughness. The overview has shown that there is no agreement on the usage of the descriptors and is not clear which descriptor is the best. One problem has been in a large scale classify shape properties. Image analysis seems according to the review to be a promising tool, it has advantages as low time consumption or repeatability. But the resolution in the processed image needs to be considered since it influences descriptors such as e.g. the perimeter. Shape definitions and its potential role in soil mechanics are discussed.
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| 46. |
- Rodriguez, Juan, et al.
(författare)
-
Mechanical weathering effect on tailing particles
- 2016
-
Ingår i: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM.
-
Konferensbidrag (refereegranskat)abstract
- 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.
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| 47. |
- Rodriguez, Juan, et al.
(författare)
-
Particle shape determination by two-dimensional image analysis in geotechnical engineering
- 2012
-
Ingår i: Proceedings of Nordic Conference on Soil Mechanics and Geotechnical NGM. - Copenhagen : Danish Geotechnical Society. - 9788789833279 ; , s. 207-218
-
Konferensbidrag (refereegranskat)abstract
- Particle shape of soil aggregates is known to influence several engineering properties; such as the internal friction angle, the permeability etc. Previously shape classification of aggregates has mainly been performed by ocular inspection and e.g. by sequential sieving. In geotechnical analysis has been a lack of an objective and rational methodology to classify shape properties by quantitative measures.Recent development in image analysis processing has opened up for classification of particles by shape. In this study 2D-image analysis has been adapted to classify particle shape for coarse grained materials. This study covers a review of soil classification methods for particle shape and geometrical shape descriptors. The image analysis methodology is tested and it is investigated how the results are affected by resolution, magnification level and type of shape describing quantity. Evaluation is carried out on as well idealized geometries as on soil samples. The interpreted results show that image analysis is a promising methodology for particle shape classification. But since the results are affected by the image acquisition procedure, the image processing, and the choice of quantity, there is a need to establish a methodology to ensure the objectivity in the particle shape classification.
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| 48. |
- Rodriguez, Juan, et al.
(författare)
-
Shear Strength in Uniformed Sized Tailing Particles
-
Ingår i: International Journal of Geotechnical Engineering. - 1938-6362 .- 1939-7879.
-
Tidskriftsartikel (refereegranskat)abstract
- Mining industry provides mineral to the modern society. Minerals are indispensable raw materials for commodities. A by-product of the mineral extraction is the mine waste also called tailings. Tailings are safety storage in tailing dams. Tailings dams troughs the history had had incidents and failures. Economic, environmental and social consequences of a tailing dam failure could be devastating. Soil strength is given by the consolidation, particle shape, stresses path, water content, hydraulic conductivity among other factors. Change on these factors produces changes in the soil strength. The development of economical and fast tests could improve the safety of the tailings deposits. Drained direct shear tests using uniformed graded tailing particles were performed. Three different size ranges 0.25, 0.125 and 0.063mm were used. Effect of particle size on shear strength and the effect of shearing on the tailing particles were studied. Normal consolidation pressure, void ratio, particle size and particle shape were monitored properties. Strength of the tailings was related with the monitored properties to suggest four empirical relations, two of them base in the morphology of the particle and two bases in the angularity. Results have shown that particle elongation diminishes the tailings strength but the angularity increases the strength. Particle size results are ambiguous and seem to be more related with the shape descriptor.
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| 49. |
- Svedberg, Bo, et al.
(författare)
-
FUD - SALA : provsträcka med stabilisering av obundna lager
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The objective of the project is to develop two applications, in which a subbase is stabilized using binders, for full scale demonstration. The binders that were used are cement, Merit 5000 and fly ash. The work indicates that stabilization of unbound layers are expected to improve the bearing capacity of the road construction though the total depth of the structure is reduced. The developed applications are durable against freezing and thawing cycles, will not be lifting due to frost and are not considerably insulating. In a life cycle cost perspective the applications are likely to be favourable. Next step is to perform a full scale demonstration where amongst other knowledge regarding determination of modulus, frost durability and cost aspects related to maintenance should be developed further.
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| 50. |
- Söderström, Patrik, et al.
(författare)
-
Snow grooming using machine guidance for piste management processes : Case study: Ormberget ski piste
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The snow is an increasingly precious commodity to the ski industry's production of pistes. To preserve this commodity is the basis for economic production. The wear on the groomed snow consists primarily of two reasons: skiers and melting. A slope that is optimally processed will last longer and require less maintenance. In addition to this obvious that maintenance must be planned based on where wear has taken place there is an additional planning variable, namely time. Timing is of utmost importance when it comes to snow as a material. A process model will be presented covering a systematic approaches how road construction technologies can be adapted to the snow grooming process. The expected results are a process model which can be used in order to optimize the snow grooming management in order to extend the skiing season. There is possibly two ways of doing this. Firstly to optimize the snow mass haul management process during the skiing season. Secondly re-build the different piste off season to create better environmental conditions during season. This study consists of four kinds of data. Laser scanned data for 3D terrain modeling of ski piste (ground) and collected data by snow groomer for 3D terrain modeling of ski piste during the objective period of investigation. The differences between 3D terrain models by laser scanning and snow groomer is representative of snow depth for corresponding day. Furthermore, in order to verify the method, snow depth and snow surface are measured by group of students from Luleå University of Technology.
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