DOCSLIB.ORG

Frost Action and Foundations Penner, E.; Crawford, C

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Frost Action and Foundations Penner, E.; Crawford, C NRC Publications Archive Archives des publications du CNRC Frost action and foundations Penner, E.; Crawford, C. B. This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur. NRC Publications Record / Notice d'Archives des publications de CNRC: https://nrc-publications.canada.ca/eng/view/object/?id=72a0db40-5304-473d-848e-a0f831b43c2e https://publications-cnrc.canada.ca/fra/voir/objet/?id=72a0db40-5304-473d-848e-a0f831b43c2e Access and use of this website and the material on it are subject to the Terms and Conditions set forth at https://nrc-publications.canada.ca/eng/copyright READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE. L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site https://publications-cnrc.canada.ca/fra/droits LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB. Questions? Contact the NRC Publications Archive team at [email protected]. If you wish to email the authors directly, please see the first page of the publication for their contact information. Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à [email protected]. NATIONAL RESEARCH COUNCIL OF CANADA DIVISION OF BUILDING RESEARCH FROST ACTION AND FOUNDATIONS by . E. Penner and C.B. Crawford Presented at the 27th Annual University of Minnesota Soil Mechanics and Foundation Engineering Conference February 1979 and published as DBR Paper No. 1090 of the Division of Building Research Ottawa March 1983 FROST ACTION AND FOUNDATIONS by E. Penner and C.B. Crawford ABSTRACT The relationship between climate, seasonal frost penetration and permafrost is discussed in relation to construction activities. The nature of the ground thermal regime, the mechanism of frost heaving, and the criteria for frost susceptibility of earth materials are outlined. Practical examples related to the design and construction of building foundations, roads, runways and ice rinks are described and problems of freezing during construction activities and thaw settlement of the ground are reviewed. Les auteurs 6tudient les relations entre le climat, la p6n6tration du gel saisonnier et le pergglisol en fonction des activitge de construction. 11s examinent la nature du rkgime thermique du sol, la mgcanique du soul2vement di3 au gel et les critsres de giSlivit6 de diffgrents sols. Les auteurs prgsentent des exemples pratiques relatifs 2 la conception et 3 la construction de fondations, de routes, de pistes d'atterrissage et de patinoires. 11s passent aussi en revue les problsmes du gel en cours de construction et du tassement du sol par le d6gel. In southern Canada and the northern United States the ground freezes every winter and thaws in the spring. Farther north the ground is perennially frozen in a condition called permafrost. The rate and depth of freezing or thawing is of special interest to those involved with the construction of buildings, roads, airports apd other modern structures or service facilities. There are so many factors influencing the freezing and thawing of the ground that precise computations of the change in phase are difficult if not impossible. Nevertheless, a general appreciation of the factors often permits reaeonable predictability. This paper diecusees the relationship between climate and ground temperatures and the mechanism of frost heaving in relation to a variety of engineering problems. Although the temperature of the ground tends to reflect the temperature of the air, the Mean Annual Ground Temperature (MAGT) is always higher (at least in northern latitudes) than the Mean Annual Air Temperature (MAAT). The primary reason for this is the influence of snow cover on the surface heat exchange. Summer vegetation has a more complex influence involving both evapotranspiration and shading. Other external factors include sunshine, rainfall, relative humidity, wind speed, precipitation and slope of the surface. Average ground temperatures are determined by external factors, but variations (daily and seasonal) are controlled by three intrinsic thermal properties: volumetric heat capacity Cv, thermal conductivity K, and the latent heat of water. The water content of the ground obviously has a great influence on these three variables and because water content varies with climate, soil type and drainage conditions, this is further evidence of the difficulties associated with the computation of ground temperatures. Volumetric heat capacity, thermal conductivity, and the latent heat capacity all increase with increasing water content. The ratio K/Cv, called thermal diffusivity, is a measure of the ease with which unfrozen soil will change temperature. It is usually a maximum at fairly low water contents. As the soil water freezes, the changes in the icelwater ratio and the latent heat of fusion become important factors in ground temperature calculations. In addition, in frost-susceptible soils the amount of water moved to the freezing plane must be estimated; this introduces further errors. Figure 1 shows monthly average ground temperatures in clay soil with a natural surface cover (grass and undisturbed snow). Note that at a depth of 4.5 m (15 ft) the minimum temperature occurs in July and the maximum in December, in each case about 6 months out of phase with the air temperatures. It may also be noted that there was little if any freezing of the ground under natural snow cover, although frost penetrated about 0.9 m (3 ft) under adjacent snow-cleared conditions (Crawford and Legget, 1957). Figure 2 shows the Mean Annual Ground Temperature profile for sites with natural snow cover (curve A) and snow cleared (curve B) at Ottawa, Ontario and for a snow-cleared area (curve C) at Knob Lake (Schefferville, Quebec). The MAGT varies imperceptibly with depth under natural snow cover (A), but under an adjacent snow- cleared roadway the MAGT near the surface is substantially lower (B). Figure 3 illustrates differences between the MAGT and MAAT for several locations in Canada. These differences vary from about 13"~at Vancouver to 7OC at Kapuskasing in northern Ontario (Williams and Gold, 1976). FROST PxmTuTIOH From an engineering point of view, one of the most important interests in ground temperatures concerns the depth of frost penetration. This value is needed for locating water and sewer services and the design of roads, runways, and many types of foundations. The prediction of frost penetration by computation is difficult because of the multitude and complexity of variables. The best way to establish the maximum, minimum and average depth of frost penetration is to ask the people who make excavations the year round, the city water department. An alternative is to refer to a reasonably well-established relationship between air temperatures and frost penetration and modify the result to account for major variations in surface or soil conditions. The general relationship between air temperatures and frost penetration was established by an extensive investigation of frost penetration through granular base courses under snow-cleared airport pavements in the northern United States (U.S . Corps of Engineers, 1949). The results of these studies showed a general relationship between the maximum depth of freezing and the Freezing Index (F.I.) - the cumulative total of degree days of air temperature below freezing during the entire winter. The F.I. is calculated using the mean daily temperatures with subtractions for days above freezing. The relationship between frost penetration and F.I. is commonly called the "Design Curve." The Design Curve has, of course, some limitations. It applies to snow-free surfaces and granular soils. It is intended to give an estimate of the maximum frost penetration during the entire winter - its use for estimating penetration some time during the winter is less reliable. It does not take into account the water content of the soil - the most important intrinsic factor. W.G. Brown (1964) calculated frost penetrations for a variety of soils with a range of water contents and for dry sand and rock using the modified Neumann solution and the Kersten (1949) values for thermal properties. He found that the results varied by a factor of less than 2 to 1, and they bracketed the Design Curve. Although Brown does not recommend calculating frost penetration, he did use his calculations and additional field data to recommend a slight change in slope of the original Design Curve as shown in Figure 4. The average F.I. can be computed from meteorological records or estimated from a Freezing Index map such as is illustrated in Figure 5 (Boyd, 1973; Burn, 1976). Once a value for frost penetration is obtained from the Design Curve, judgment must be applied to account for local conditions. Experience has shown, for example, that 0.3 m (1 ft) of natural snow cover will reduce frost penetration by at least 0.3 m and up to 0.6 m (1-2 ft). Compact snow or ice will reduce penetration by an amount approximately equal to its thickness. Frost will penetrate less into wet clay than into granular soils, but the penetration into almost dry granular soils may be greater than that estimated by the Design Curve. The difficulties in computing ground temperatures have led to the development of graphical methods for solving field problems dealing with natural or engineering structures lying directly on the ground surface (Brown, W.G., 1963). These include: 1) Shallow lakes and rivers on unfrozen or frozen soil (permafrost); 2) Basementless buildings, either heated or cooled; 3) Ice rinks; 4) Streets and streets bordered by buildings; and 5) Roads and runways.
Load more

Recommended publications
  • Sensors and Measurements Discussion
    “Measurements for Assessment of Hydrate Related Geohazards” Report Type: Topical No: 41330R07 Starting March 2002 Ending September 2004 Edited by: R.L. Kleinberg and Emrys Jones September 2004 DOE Award Number: DE-FC26-01NT41330 Submitting Organization: ChevronTexaco Energy Technology Company 2811 Hayes Road Houston, TX 77082 DISCLAIMER “This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.” ii Abstract Natural gas hydrate deposits are found in deep offshore environments. In some cases these deposits overlay conventional oil and gas reservoirs. There are concerns that the presence of hydrates can compromise the safety of exploration and production operations [Hovland and Gudmestad, 2001]. Serious problems related to the instability of wellbores drilled through hydrate formations have been document by Collett and Dallimore, 2002]. A hydrate-related incident in the deep Gulf of Mexico could potentially damage the environment and have significant economic impacts.
    [Show full text]
  • Managing Winter Injury to Trees and Shrubs
    Publication 426-500 Managing Winter Injury to Trees and Shrubs Diane Relf Extension Specialist, Horticulture, and Bonnie Appleton, Extension Specialist, Horticulture; Virginia Tech Reviewed by David Close, Consumer Horticulture and Master Gardener Specialist, Horticulture, Virginia Tech Introduction evergreen needles or leaves. It is worst on the side facing the wind. This can be particularly serious if plants are It is often necessary to provide extra attention to plants near a white house where the sun’s rays reflect off the in the fall to help them over-winter and start spring in side, causing extra damage. peak condition. Understanding certain principles and cultural practices will significantly reduce winter damage Management: Proper watering can is a critical factor in that can be divided into three categories: desiccation, winterizing. If autumn rains have been insufficient, give freezing, and breakage. plants a deep soaking that will supply water to the entire root system before the ground freezes. This practice is Desiccation especially important for evergreens. Watering when there Desiccation, or drying out, is a significant cause of dam- are warm days during January, February, and March is age, particularly on evergreens. Desiccation occurs when also important. water leaves the plant faster than it is taken up. Several environmental factors can influence desiccation. Needles Also, mulching is an important control for erosion and and leaves of evergreens transpire some moisture even loss of water. A 2-inch layer of mulch will reduce water during the winter months. During severely cold weather, loss and help maintain uniform soil moisture around the ground may freeze to a depth beyond the extent of roots.
    [Show full text]
  • Permafrost Soils and Carbon Cycling
    SOIL, 1, 147–171, 2015 www.soil-journal.net/1/147/2015/ doi:10.5194/soil-1-147-2015 SOIL © Author(s) 2015. CC Attribution 3.0 License. Permafrost soils and carbon cycling C. L. Ping1, J. D. Jastrow2, M. T. Jorgenson3, G. J. Michaelson1, and Y. L. Shur4 1Agricultural and Forestry Experiment Station, Palmer Research Center, University of Alaska Fairbanks, 1509 South Georgeson Road, Palmer, AK 99645, USA 2Biosciences Division, Argonne National Laboratory, Argonne, IL 60439, USA 3Alaska Ecoscience, Fairbanks, AK 99775, USA 4Department of Civil and Environmental Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775, USA Correspondence to: C. L. Ping ([email protected]) Received: 4 October 2014 – Published in SOIL Discuss.: 30 October 2014 Revised: – – Accepted: 24 December 2014 – Published: 5 February 2015 Abstract. Knowledge of soils in the permafrost region has advanced immensely in recent decades, despite the remoteness and inaccessibility of most of the region and the sampling limitations posed by the severe environ- ment. These efforts significantly increased estimates of the amount of organic carbon stored in permafrost-region soils and improved understanding of how pedogenic processes unique to permafrost environments built enor- mous organic carbon stocks during the Quaternary. This knowledge has also called attention to the importance of permafrost-affected soils to the global carbon cycle and the potential vulnerability of the region’s soil or- ganic carbon (SOC) stocks to changing climatic conditions. In this review, we briefly introduce the permafrost characteristics, ice structures, and cryopedogenic processes that shape the development of permafrost-affected soils, and discuss their effects on soil structures and on organic matter distributions within the soil profile.
    [Show full text]
  • Ground Freezing and Frost Heaving Penner, E
    NRC Publications Archive Archives des publications du CNRC Ground freezing and frost heaving Penner, E. For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous. Publisher’s version / Version de l'éditeur: https://doi.org/10.4224/40000788 Canadian Building Digest, 1962-02 NRC Publications Archive Record / Notice des Archives des publications du CNRC : https://nrc-publications.canada.ca/eng/view/object/?id=15f6f5eb-a070-4327-aec4-71472a903119 https://publications-cnrc.canada.ca/fra/voir/objet/?id=15f6f5eb-a070-4327-aec4-71472a903119 Access and use of this website and the material on it are subject to the Terms and Conditions set forth at https://nrc-publications.canada.ca/eng/copyright READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE. L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site https://publications-cnrc.canada.ca/fra/droits LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB. Questions? Contact the NRC Publications Archive team at [email protected]. If you wish to email the authors directly, please see the first page of the publication for their contact information. Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à [email protected]. Canadian Building Digest Division of Building Research, National Research Council Canada CBD 26 Ground Freezing and Frost Heaving Originally published February 1962 E.
    [Show full text]
  • Report No. REC-ERC-82-17, “Frost Action in Soil Foundations And
    REC-ERC-82-17 June 1982 Engineering and Research Center U.S. Department of the Interior Bureau of Reclamation 7-2090 (4-81) . .- water ana Power ~ TECHNICAL RE lPORT STANDARD TITLE PAGE 3. RECIPIENT’S CATALOG NO. 5. REPORT DATE Frost Action in Soil Foundations and June 1982 Control of Surface Structure Heaving 6. PERFORMING ORGANIZATION CODE 7. AUTHORIS) 8. PERFORMING ORGANIZATION C. W. Jones, D. G. Miedema and J. S. Watkins REPORT NO. REC-ERC-B2- 17 9. PERFORMING ORGANIZATION NAME AN0 ADDRESS 10. WORK UNIT NO. Bureau of Reclamation Engineering and Research Center 11. CONTRACT OR GRANT NO. Denver, Colorado 80225 13. TYPE OF REPORT AND PERIOD COVERED 12. SPONSORING AGENCY NAME AND ADDRESS Same 14. SPONSORING AGENCY CODE DIBR IS. SUPPLEMENTARY NOTES Microfiche and/or hard copy available at the Engineering and Research Center, Denver, CO I Ed: ROM 1I6 ABSTRACT This is a report on frost action in soil foundations that may influence the performance of irriga- tion structures. The report provides background information and serves as a general guide for design, construction, and operation and maintenance. It also includes information on the mechanics of frost action, field and laboratory investigations of potential frost problems, case histories of frost damage to hydraulic structures, and measures to control detrimental freezing to avoid damage. The structures mentioned include earth embankment dams with appurte- nant structures, canals with linings, and various other concrete canal structures. 7. KEY WORDS ANO OOCU~~ENT *NALY~IS 3. DESCRIPTORS-- / frost action/ frost heaving/ ice lenses/ frost protection/ foundation dis- placements/ behavior (structural) 5.
    [Show full text]
  • The Rheology of Frozen Soils
    The Rheology of Frozen Soils Lukas U. Arenson*1, Sarah M. Springman2, Dave C. Sego1 1 Department of Civil & Environmental Engineering, UofA Geotechnical Centre, 3-065 Markin/CNRL Natural Resources Engineering Facility, University of Alberta, Edmonton, Alberta T6G 2W2, Canada 2 Institute for Geotechnical Engineering, ETH Zurich, Wolfgang-Pauli-Str. 15, 8093 Zurich, Switzerland *E-mail: [email protected] Fax: x1.780.492.8198 Received: 2.6.2006, Final version: 2.8.2006 Abstract: The rheological behaviour of frozen soils depends on a number of factors and is complex. Stress and tempera- ture histories as well as the actual composition of the frozen soil are only some aspects that have to be consid- ered when analysing the mechanical response. Recent improvements in measuring methods for laboratory inves- tigations as well as new theoretical models have assisted in developing an improved understanding of the thermo-mechanical processes at play within frozen soils and representation of their response to a range of per- turbations. This review summarises earlier work and the current state of knowledge in the field of frozen soil research. Further, it presents basic concepts as well as current research gaps. Suggestions for future research in the field of frozen soil mechanics are also made. The goal of the review is to heighten awareness of the com- plexity of processes interacting within frozen soils and the need to understand this complexity when develop- ing models for representing this behaviour. Zusammenfassung: Das rheologische Verhalten von gefrorenen Böden hängt von einer grossen Anzahl verschiedener Faktoren ab und ist äusserst komplex. Druck- und Temperaturgeschichte, sowie die Zusammensetzung des gefrorenen Bodens sind nur einige Aspekte, welche betrachtet und berücksichtigt werden müssen, wenn man die mecha- nischen Eigenschaften analysiert.
    [Show full text]
  • Lecture 1 (Pdf)
    GFD 2006 Lecture 1: Introduction to Ice Grae Worster; notes by Rachel Zammett and Devin Conroy March 15, 2007 1 Introduction Our aim in this course is to understand some of the processes associated with ice in the natural environment. Figure 1 shows the location of some of Earth's ice during the north- ern winter. These ice deposits may be categorized as sea ice, ice sheets and shelves, and permafrost. Figure 1: Satellite image showing the ice cover in the northern hemisphere during northern winter, showing sea ice lying in the Arctic basin, the permanent ice sheet over Greenland and permafrost in the exposed land surface. 2 Ice sheets Firstly, figure 1 shows the ice sheet that covers approximately 80% of Greenland. This is about 105 years old and reaches depths of 2{3 kilometers. On large scales, ice can be treated as a highly viscous, non-Newtonian fluid that can flow because it is a polycrystalline solid and contains a percentage of unfrozen water (figure 2). Looking on a scale of about 100µm, 1 Figure 2: Image of the intersection of four ice grains. Between these grains lie the veins containing liquid water and dissolved impurities. The scale bar on this picture is 100 µm. we can see the ice grain junctions and the veins which lie between them. The liquid water contained in the veins between the ice crystals lubricates the flow, allowing the ice to flow more easily. This water can also transport dissolved impurities, which will therefore move relative to the ice crystals; this is important when analyzing ice cores, for example.
    [Show full text]
  • Frost Heaving – Winter Woes Require Summer Remedies”
    “FROST HEAVING – WINTER WOES REQUIRE SUMMER REMEDIES” As summer months approach, the symptoms of frost heaving that were present during the winter often disappear. This does not mean the cause and possible defects have been eliminated. If evidence of frost heaving was present in and around your dwelling last winter, now is the time to indentify possible causes so that repairs can be made before the next winter season. What is “frost heaving”? Frost heaving is a movement of soil caused by the formation of ice lenses within the ground. It is a natural occurrence in Minnesota and other northern climates during the winter and early springtime. Frost heaving occurs when water in the soil expands as it freezes. Generally, water expands by approximately 9% in volume when frozen. This expansion creates significant forces that can move and destroy what had seemingly appeared to be solid construction. Soil movement can vary from something that is barely visible to displacement that is many inches. Causes and consequences of frost heaving. Three conditions typically exist for frost heaving to occur. These are: 1. A sufficiently cold climate (such as found in Minnesota) so that freezing temperatures penetrate into the ground; 2. A sufficient amount of water in the soil; and 3. A type of soil that is frost susceptible When water in soil freezes, an ice lens is formed. Ice lenses collect nearby water in the soil by capillary action, which increases the size of the lens. The force created by the formation of the ice lens will heave soil and move the surface of the ground upward.
    [Show full text]
  • Genesis and Geometry of the Meiklejohn Peak Lime Mud-Mound
    University of Calgary PRISM: University of Calgary's Digital Repository Science Science Research & Publications 2001-12 Genesis and geometry of the Meiklejohn Peak lime mud-mound, Bare Mountain Quadrangle, Nevada, USA: Ordovician limestone with submarine frost heave structures- a possible response to gas clathrate hydrate evolution Krause, Federico F. Elsevier Krause, Frederico F.. (2001). "Genesis and geometry of the Meiklejohn Peak lime mud-mound, Bare Mountain Quadrangle, Nevada, USA: Ordovician limestone with submarine frost heave structures- a possible response to gas clathrate hydrate evolution". In: Carbonate mounds: Sedimentation, organismal response and diagenesis, D. W. Kopaska-Merkel and D. C. Haywick (editors). Sedimentary Geology, 145: 189-213. http://hdl.handle.net/1880/44457 journal article Downloaded from PRISM: https://prism.ucalgary.ca Sedimentary Geology Sedimentary Geology 145 (2001) 189-213 Genesis and geometry of the Meiklejohn Peak lime mud-mound, Bare Mountain Quadrangle, Nevada, USA: Ordovician limestone with submarine frost heave structures-a possible response to gas clathrate hydrate evolution Federico F. Krause* University qfcalgarv. Department of Geology and Geophysics, 2500 Universiiy Drive N. K, Calgaly, Alberta, Canada T2N IN4 Received 3 August 2000; accepted 15 May 2001 Abstract During the Early Middle Ordovician (Early Whiterockian) the Meiklejohn Peak lime mud-mound, a large whaleback or dolphin back dome, grew on a carbonate ramp tens to hundreds of kilometres offshore. This ramp extended from the northwest margin of Laurentia into the open waters of the ancestral Pacific Ocean to the north. The mound developed in an outer ramp environment, in relatively deep and cold water. A steep northern margin with a slope that exceeds 55' characterizes the mound.
    [Show full text]
  • Eastern Siberia) Lara Hughes-Allen, Frédéric Bouchard, Isabelle Laurion, Antoine Séjourné, Christelle Marlin, Christine Hatté, F
    Seasonal patterns in greenhouse gas emissions from different types of thermokarst lakes in Central Yakutia (Eastern Siberia) Lara Hughes-Allen, Frédéric Bouchard, Isabelle Laurion, Antoine Séjourné, Christelle Marlin, Christine Hatté, F. Costard, Alexander Fedorov, Alexey Desyatkin To cite this version: Lara Hughes-Allen, Frédéric Bouchard, Isabelle Laurion, Antoine Séjourné, Christelle Marlin, et al.. Seasonal patterns in greenhouse gas emissions from different types of thermokarst lakes in Central Yakutia (Eastern Siberia). Limnology and Oceanography, Association for the Sciences of Limnology and Oceanography, In press, 10.1002/lno.11665. hal-03086290 HAL Id: hal-03086290 https://hal.archives-ouvertes.fr/hal-03086290 Submitted on 8 Jan 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Limnol. Oceanogr. 9999, 2020, 1–19 © 2020 Association for the Sciences of Limnology and Oceanography doi: 10.1002/lno.11665 Seasonal patterns in greenhouse gas emissions from thermokarst lakes in Central Yakutia (Eastern Siberia) Lara Hughes-Allen ,1,2* Frédéric
    [Show full text]
  • Motivation for Frost Heave Author(S): JG Dash Source
    Thermomolecular Pressure in Surface Melting: Motivation for Frost Heave Author(s): J. G. Dash Source: Science, New Series, Vol. 246, No. 4937 (Dec. 22, 1989), pp. 1591-1593 Published by: American Association for the Advancement of Science Stable URL: http://www.jstor.org/stable/1704667 Accessed: 22-11-2015 23:33 UTC Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://www.jstor.org/page/ info/about/policies/terms.jsp JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. American Association for the Advancement of Science is collaborating with JSTOR to digitize, preserve and extend access to Science. http://www.jstor.org This content downloaded from 132.174.254.159 on Sun, 22 Nov 2015 23:33:34 UTC All use subject to JSTOR Terms and Conditions increasesthe mass input, and melting has GeophysicalUnion, Washington,DC, 1985), pp. 22. Glacio-isostaticuplift ended 4000 to 5000 yearsago 59-85. (A. Weidick,in Geologyof Greenland,A. Escherand little effect.Below the equilibriumline, in- 9. H. J. Zwally,A. C. Brenner,J. A. Major, R. A. W. S. Watt, Eds. (The GeologicalSurvey of Green- creasesln preclpltatlonreduce t le net sum- Bindschadler,J. G. Marsh, Sciet1ce 246, 1587 land, Denmark,1976), p. 450. Figure 3 in (1) mer ablationand partiallyoiset increasesin (1989).
    [Show full text]
  • Frost Heave Properties Assessment of the Soils for the Road Pavement Design
    Frost Heave Properties Assessment of the Soils for the Road Pavement design Final report Customer: VAS “Latvijas Valsts ceļi” Contractor: SIA “Vides eksperti” Sub-contractors: University of Latvia SIA “Ceļu eksperts” Experts: Māris Krievāns, PhD – University of Latvia Jānis Karušs, PhD – University of Latvia Ivars Pavasars, PhD – SIA “Vides eksperti” Aigars Strežs, MSc– SIA “Ceļu eksperts” Rīga 2019 KOPSAVILKUMS Apstiprinu, ___________________________ (vārds, uzvārds, paraksts) Pētniecības projekta nosaukums: Grunšu sala pacēluma īpašību novērtēšana ceļu segas projektēšanas vajadzībām Līguma numurs LVC2018/1.10/1/AC Līguma slēgšanas datums 2018. gada 7. jūnijs Pētniecības projekta stadija Gala ziņojums Starpziņojumu kopējais skaits Viens Ziņojuma nodošanas datums 2019. gada 18. marts Pētniecības projekta stadijas 2018. gada 12. novembris - 2019. gada 18. marts izstrādes periods Lappušu skaits 138 (neieskaitot pielikumus) Disks vai cits datu nesējs (ir/nav) Ir Eksemplāru skaits 1 Pētniecības programma JAUNU TEHNOLOĢIJU IZPĒTES PROGRAMMA 2017. - 2019. GADAM Pētniecības projekta izpildītāji Grāds,Vārds, Uzvārds Paraksts Pētniecības projekta vadītājs PhD, Ivars Pavasars Pētnieks PhD, Jānis Karušs Pētnieks PhD, Māris Krievāns Pētnieks MSc, Aigars Strežs Projektu finansē VAS ″Latvijas valsts ceļi″ / Satiksmes ministrija SIA “Vides eksperti”, Latvijas Universitāte, SIA “Ceļu Partneri eksperts” Apraksts Darba izstrādes ietvaros ir veikts zinātniskās literatūras apskats un analīze, kas koncentrējas uz sala pacēluma teorētiskajiem aspektiem, kā arī apskatīti un salīdzināti pašreiz pasaulē lietotie izpētes standarti un metodes sasaluma un atkusuma ietekmes novērtēšanai gruntīm. Sniegts vispārējs Latvijas klimatisko apstākļu apskats, tendences un analizēti LVC meteoroloģisko staciju dati. Rezultāti atspoguļoti arī grafiski uz Latvijas kartes. Lai novērtētu dažādu Latvijā sastopamo grunšu sala pacēluma īpašības un konstatētu svarīgākos to noteicošos parametrus, savākti Latvijā raksturīgo dažādu grunšu paraugi aptverot pēc iespējas vairāk dažādus grunšu tipus.
    [Show full text]