Showing papers on "Permafrost published in 1972"

The world of underground ice

Abstract: Underground ice is restricted to permafrost areas where its distribution is sporadic and often unpredictable. A knowledge of the distribution and abundance of underground ice is essential to northern development, because a variety of man induced disturbances can cause underground ice to thaw, often with serious consequences. The criteria for a classification of the principal types of underground ice are the source of the water prior to freezing and the processes which transfer water to the freezing plane. The origin of massive icy bodies in the Western Arctic of North America is explained by a water expulsion theory. The excess water now found in the icy bodies is attributed to water expelled from coarse textured sediments by the downward growth of permafrost. The suggested mechanism is illustrated by three pingos which have grown since 1950. The role of glaciation in the formation of relic offshore permafrost in relatively shallow Arctic coastal areas is examined. The evidence suggests that offs...

Palsas and peat plateaus in Central Manitoba and Saskatchewan

Abstract: Twenty-six peat plateaus and eight palsas were examined near Flin Flon, Manitoba at the southern limit of discontinuous permafrost Peat plateaus in different developmental stages were identified on the basis of their morphology The permafrost is entirely within the peat in all peat plateaus within the study area, but extends into mineral subsoil under all palsas examined Doming in peat plateaus is largely explained by volume change due to change from unfrozen to frozen stage, and by buoyancy of the frozen mass floating on unfrozen peat The occurrence of aggrading and degrading peat plateaus in the same area indicates that all developmental stages are permitted by the present climate

Offshore Permafrost and Ground Ice, Southern Beaufort Sea, Canada

Abstract: The distribution and origin of offshore permafrost is discussed for the southern Beaufort Sea. Two types of permafrost are identified: permafrost which is in thermal equilibrium with negative sea bottom temperatures, and disequilibrium permafrost, which is not in equilibrium with either positive or negative sea bottom temperatures. The origin of permafrost is considered in terms of the Quaternary period when coastal areas were exposed to cold air temperatures and then submerged. The effect of warm river waters, primarily from the Mackenzie River, is shown to ameliorate coastal water temperatures and may be responsible for a thin active layer at some sites. Water quality and oxygen isotope ratios are given for some samples. The evidence suggests that some relic land permafrost, with ground ice, is present beneath the southern Beaufort Sea. Perforated permafrost should be present, but not extensive thermokarst depressions. By inference, permafrost probably underlies much of the Canadian Arctic waters, altho...

Relic Pleistocene Permafrost, Western Arctic, Canada

Abstract: Icy layers and interbedded frozen sediments along the Arctic Coastal Plain of northwestern Canada have been subjected to glacial deformation. Radio-carbon dates indicate that the deformation took place more than 40,000 years ago.

Field Tests of Grouted Rod Anchors in Permafrost

Abstract: The use of guyed towers for power transmission and communication systems in northern Canada has received increased attention in recent years. In many cases perennially frozen ground (permafrost) poses special problems. The resistance of frozen soil to uplift forces must be evaluated for the design of anchors of guyed structures built on permafrost. There is little experience or information available, however, concerning the behavior of frozen soil in response to uplift forces or the capacity of various types of anchors. A field study of anchors in permafrost was therefore undertaken by the Division of Building Research of the National Research counci l of Canada to evaluate, in particular, the displacements associated with long-term creep of frozen soil under load. initial appraisal of various kinds of anchors suggested that grouted rod anchors were a type that should be investigated. Early in 1967 a total of 18 such anchors (nine at each site) were installed in permafrost at Thompson and Gillam, Manitoba. This paper describes the installation and testing procedures and the results of the test programs conducted on the anchors at both sites. In the analysis of the results the creep behavior of grouted anchors is related to U basic creep parameters of frozen soil, taking into account the effects of temperature and normal pressure. The theory employed allows field creep data to be used for estimating the long-term adfreeze strength of frozen soil, information that is required in the design

Control of permafrost degradation beneath a roadway by subgrade insulation

Abstract: The opinions , findings and conclusions expressed i n this publication are those of the authors and are not necessarily those held by the Federal Highway Administration. A section of new roadway across a muskeg area near Chitina, Alaska, under-l a i n by perennially frozen meat, was constructed w i t h both two and four inch thick polystyrene foam insulation 1 ayers t o control thawing and prevent roadway surface settlements. The adjacent uninsulated roadway areas and an area of undisturbed ground were also studied f o r comparison purposes. This report discusses the construction operations and presents settlement data and a i r , surface, and subsurface temperature data obtained d u r i n q the three year period following construction. were very small i n b o t h insulated areas. The adjacent uninsulated sections showed average settlements approximately ten times qreater than the insulated sections, with severe settlement differentials resulting i n the need f o r frequent regrading and patching. A1 though the average temperature of the underlying permafrost was-approximately 30°F, no residual thaw layers were developed i n any o f the sections studied, I t i s concluded t h a t roadway subgrade insulation layers can be of major benefit in control 1 i n g pos t-construction surface settlements. Observations of the insulated sections will continue, t o determine the long term performance of insulated roadways over permafrost. Newly constructed roadways crossing permafrost t e r r a i n originally covered w i t h vegetation have the effect of increasing the amplitude of the seasonal surface and subsurface temperature variations, and also of. altering the mean annual surface temperature. f r o s t table t o the new thermal conditions occurs over a period of years, Readjusting of the perma

Permafrost and well protection

Abstract: A method for protecting a permafrost zone and a well passing through that permafrost zone wherein a pipe string is placed in said well so as to extend through at least part of said permafrost zone and is heated over its length in said permafrost zone using electrical energy thereby avoiding alternate freezing and thawing of the permafrost and sloughing of the permafrost due to thermal cycling and preventing freeze up of the well itself.

Settlement of Pipeline on Thawing Permafrost

Abstract: A buried oil pipeline in permafrost will thaw the frozen soil around it, and will settle as the thawed soil consolidates Because the amount of ice in the soil varies from point to point along the pipe alignment, the settlement will be uneven, and will induce bending in the pipe Thaw settlement estimates from single boreholes give no information about the possible magnitude of differential settlements, and instead statistical measures of the intensity of fluctuations in thaw settlement have to be used Alternative sources of the required data are suggested, and two different ways of estimating the effects on the pipe are described, one way being based on random process theory and the other on statistical simulation The flexural stiffness of the pipe modifies the settlement, and methods of taking this effect into account are explained

Well production method for permafrost zones

Abstract: A method and apparatus for producing a warm fluid from a well through casing, the casing passing through a permafrost zone, wherein the permafrost is insulated from melting by the combined use of vacuum and solid thermal insulation.

Method of supporting a hot oil pipeline through permafrost

Abstract: An underground hot oil pipeline is maintained in a stable location by maintaining the permafrost in a frozen condition. This frozen condition is maintained by a combination of insulation means to reduce heat loss from the pipeline into the permafrost to below about 1 calory per square centimeter per day and by the provision of a plurality of elongated thermally conductive strips extending outwardly from the exterior of the pipeline insulating means in order to conduct that heat which flows from the immediate region of the pipeline insulating means into the surrounding permafrost. Above ground heat radiating means may be advantageously utilized to help conduct heat into the surrounding atmosphere.

On the Permafrost at the Summit of Mt. Fuji

Abstract: The observations on the active layer of permafrost were carried out at the summit of Mt. Fuji since 1970. The observational results can be summerized as follows.The existence of permafrost was confirmed at the summit of Mt. Fuji (3, 776.3m above sea level, 35°21'N, 138°44'E), not only within the small area near the Fuji-san Weather Station where the existence of frozen soil was observed at summer before, but in the whole area of the crater rim of summit.The lower limit of the existence of permafrost was about 2, 800m at the northern slope and about 2, 900m at the southern slope. The mean annual air temperature at these elevation is -1.4-1.8°C.Thickness of the active layer of permafrost was 50130cm at the end of July. The active layer was thinner in the area where the deposited snow was deeper in winter. Thickness of the active layer was nearly in proportion to the square root of thawing index after disappearance of the deposited snow.

Thermal Model For Roads, Airstrips And Building Foundations In Permafrost Regions

Abstract: A thermal model describing the one-dimensional heat conduction in a layered system is developed. Up to ten homogeneous layers, each having different thermal properties, porosity, water content and thickness, can be accommodated. A periodic temperature is input for the surface condition. The computed results consist of the depth of the thawed region as a function of time. The layered model is applied to the design of foundations for roads and airstrips in permafrost regions. A sensitivity study was made to find the effect on thaw depth of varying physical properties of the materials used, the geometry of the construction and the surface temperature. The means for extension of the model to building foundation design by modification of the surface boundary condition is presented.

Preliminary ecological evaluation of the effects of air cushion vehicle tests on the arctic tundra of northern Alaska

Abstract: : Of prime concern in the Arctic is the need for an efficient means of transportation over both frozen and unfrozen arctic terrain. As part of the effort to develop such a means, the Advanced Research Projects Agency established a program to determine the potential for using an air cushion vehicle (ACV). Studies on the effects of ACV tests were conducted in two areas at Barrow, Alaska. One area was a drained lake bottom with a fairly homogeneous vegetation cover and soil type. The second area, much drier than the first, consisted of low-centered polygons composed of a wet tundra soil and a varying vegetation complex. The initial effects of the ACV tests in both in both areas were quite similar. darpa

Hydrogeochemical prospecting for blind ores in permafrost

Abstract: (1972). Hydrogeochemical prospecting for blind ores in permafrost. International Geology Review: Vol. 14, No. 10, pp. 1037-1043.

Thawing and Differential Settlement Close to Oil Wells through Permafrost

Abstract: : The paper puts forward a preliminary analysis, whose purpose is to identify the factors which determine settlements and casing stresses, and to find out what information is needed for a more precise evaluation. Bold idealizations will be made in order to isolate primary from secondary factors: thus, for example, no account is taken of the variation with depth of the initial temperature of the undisturbed permafrost layer. The heat transfer problem is briefly considered first; simple models of thaw consolidation and arching follow, and their implications for thawing around a well are then examined.

Construction and Permafrost

Abstract: : The brochure relates the pecularities of permafrost construction in everyday language Future construction outlooks are shown; new, original and progressive designs for buildings and structures and methods of accomplishing work during permafrost construction are presented, and the most important points in the development of industry in the northern regions are described (Author)