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Almost one hall of Canada's total land surface is underlain by permafrost and its existence has many implications to both scientific and engineering interests. Engineering experience has indicated that site investigations are essential in permafrost areas but no standard method for reporting permafrost conditions has been used or is available. This booklet has been prepared with the hope that the descriptive system outlined will fulfil this need.

Vibration measurements in the main powerhouse at Inuvik, NWT, were taken to determine the amplitudes of vibration present in a structure supported on pile foundations in permafrost and subjected to large dynamic periodic forces. Accelerometers were placed on the support system for the main diesel generator and on the floor and pile foundation of the one-storey industrial building. One-third octave band RMS acceleration amplitudes produced by the generator, a 5.2 MW system, are presented. In comparison to ambient acceleration amplitudes (generator off), amplitudes produced by the generator were approximately 430 times larger on the structural system supporting the generator and five to ten times larger throughout the remainder of the powerhouse.

The purpose of this paper is to develop a method for predicting the creep settlement and the bearing capacity of frozen soils under deep circular loads. The theory uses experimentally determined creep parameters of frozen soil and is intended to be applicable to the design of deep circular footings and screw anchors embedded in permafrost soils. On the basis of available experimental evidence, it was concluded that a mathematical model different from that usual in soil mechanics should be used in solving the time- dependent bearing capacity problem of such footings. The solution proposed in the paper was obtained by using the mathematical model of an expanding spherical cavity in a nonlinear viscoelastic-plastic medium with time, temperature, and normal pressure dependent strength properties. For a given footing or anchor, the theory furnishes either isochronous load-displacement curves, or load-creep rate curves, or a time-dependent bearing capacity for which formulas and graphs of nonlinear elastic-plastic bearing capacity factors are supplied. The theoretical predictability of creep rates and ultimate failure loads was checked against the results of screw anchor tests carried out by the Division of Building Research, N.R.C.C., at a permafrost site in Thompson, Manitoba. It was found that the use in the theory of the creep parameters determined by creep-pressuremeter tests performed at the site, resulted in a satisfactory agreement between the predicted and the observed behavior.

Workshops on Subsea Permafrost and Pipelines in Permafrost, November 18-19, 1985

The Soviet North, encompassing about 4 million square miles or almost 50 per cent of the total land area of the Soviet Union, is roughly comparable in area to the total land area of Canada. It is exceedingly rich in natural resources and development of these northern regions is most important and necessary to the over-all development of the Soviet Union. As in the Canadian North, long distances, difficult access, and severe climate and terrain conditions, notably permafrost which underlies about one half of the land area of both countries, pose many difficult engineering and construction problems. Northern technology is essentially the same in both countries, there being no basic differences. Large hydro-electric, mining, oil and gas, and industrial projects have been or are being developed. Living conditions are now being improved and multi-storey dwellings are being constructed in new towns and also during redevelopment of their older cities and communities in Siberia., Annual Meeting of the Canadian Construction Association, January 29, 1973, Saskatoon, Saskatchewan, Canada

Laminated frozen soils, consisting of alternate horizontal layers of dark brown clay and light brown silt, with ice lenses between the layers, are found in the northern area of ancient glacial Lake Agassiz. Laboratory tests confirmed the results of in situ ground anchor, penetrometer, and pressuremeter tests performed at Thompson, Manitoba, which showed these soils to be stronger in the horizontal direction, parallel to the layers, than in the vertical direction. Undisturbed block samples of these laminated ( varved) frozen soils were obtained and test specimens were prepared at various orientations to the direction of layering. Unconfined compression tests, using both naturally frozen and remolded frozen specimens, have shown the extent of strength anisotropy due to the natural anisotropic soil structure., Permafrost: 4th International Conference, July 17, 1983, Fairbanks, Alaska, USA

In 1972 four insulated and two uninsulated test sections were installed and instrumented on the Mackenzie Highway (a gravel-surfaced, all-season road) near Inuvik, N.W.T., to evaluate the use of extruded polystyrene board insulation to control permafrost degradation. Two test sections were insulated with a 90-mm layer of insulation, another with a 50-mm layer, and a fourth with 115 mm. Preliminary analysis had indicated that an optimum insulation thickness of about 90 mm would be required. Ground temperature and settlement observations over a 6-year period showed that permafrost aggraded under all insulated test sections, whereas under the uninsulated (control) sections it receded by as much as 60 cm. Approximately 60 cm of settlement was experienced by the control sections, about 30 cm by the 50- mm insulated section, and little or none by the sections having 90 and 115 mm of insulation. The 90 mm of insulation was shown to provide adequate protection against thawing; 50 mm of insulation was not sufficient., 4th International Conference on Permafrost, July 17, 1983, Fairbanks, Alaska, USA

The Inuvik airfield was constructed between 1956 and 1958 on a site underlain by frozen fine-grained soils containing considerable quantities of ice. Its design and performance were therefore of considerable concern. The airfield consists of an embankment of rock fill constructed on the undisturbed ground surface to a thickness sufficient to prevent, or minimize, thawing of the frozen subgrade soils: from 2.5 to 4.2 m, and averaging about 3m. The airfield was paved with asphaltic concrete in 1969. Ground temperatures were measured at several locations in the subgrade and the embankment from 1958 to 1974. All temperature observations showed that the permafrost table moved up at least 0.6 m into the fill after construction was completed in 1958 and remained at about the same level in subsequent years, even after paving. The airstrip has performed extremely well to date and has required little maintenance work., Fourth Canadian Permafrost Conference, March 2, 1981, Calgary, Alberta, Canada

Electrical potentials developed during thawing of the active layer in frozen ground have been measured at a test site in Inuvik, Northwest territories. Probes containing copper electrodes spaced at regular intervals were installed vertically in a clay hummock, in an ice-rich soil at the junction of three hummocks, and in a sandy gravel and reconstituted clay in wax-coated cardboard tubes placed in an adjacent hummock. The maximum voltage measured across the thaw boundary was of the order of 500mV in the fine- grained soil and about 200mV in the coarse-grained soil. The difference may be due to the larger amounts of moisture in the fine-grained soil., 4th International Symposium on Ground Freezing, August 5, 1985, Sapporo, Japan

This little paper records the result of a reconnaissance of some large craters near Norman Wells which was made at the request of members of the National Research Council who saw these phenomena when flying up to Norman Wells in June 1956. Even though further information is being obtained, this note is issued in this incomplete form in view of the expressed interest of members of the Council in the craters.

A field investigation was carried out at the Kelsey Generating Station of Manitoba Hydro during the period 25 March to 7 April 1963 to determine the depth of thaw that has occurred to date under and adjacent to East and West Dykes No. 2 constructed on permafrost.This report has been prepared primarily for record purposes and describes the scope of the investigations and the results obtained.

A series of field tests was carried out at a permafrost site near Thompson, Manitoba, to investigate the suitability of the Ménard Pressuremeter as a tool for in-situ determination of the rheological properites of frozen soils. Both short- term and long-term tests were conducted using the standard pressuremeter equipment with only minor modifications. Special care was taken in drilling and preparing the borehole for the tests to minimize the temperature disturbance. By using a newly developed method described in the paper, it was possible to obtain from the tests both the short-term and the long-term strength parameters. The first were obtained from conventional type pressuremeter tests, while the latter resulted from stage-loaded creep tests. In addition to the time dependent strength, the constitutive creep equation of the frozen soil was also established from the pressuremeter creep tests. The pressuremeter technique was found to be quite promising for creep testing of frozen soils. Its main advantages over laboratory methods used for similar purpose is that it is quicker, less expensive and involves a relatively large volume of soil. Its drawback is that it furnishes information on the soil behavior in only one direction, i.e., normal to the axis of the borehole which may be insufficient for foundation design if the permafrost stratum is anisotropic and contains horizontal ice lenses and layers., 2nd International Conference on Permafrost, July 1973, Yakutsk, Siberia

The role of climate and, in particular, air temperature in determining the geographical distribution of permafrost is discussed briefly for Canadian conditions. The thermal properties of permafrost materials and the climatic factors that make up the surface heat balance are discussed in general terms. The importance of surface materials in determining the ground thermal regime is illustrated by a number of theoretical calculations based on a one- dimensional finite-difference model. Using a simplified two- dimensional finite-difference model, theoretical calculations of thawing round a hot oil pipeline and freezing around a cold gas pipeline are presented and the settlement and stability problems that would result are discussed qualitatively. The importance of drainage and the effect of water bodies on permafrost is commented on. Finally, a brief review is given of current design and construction practice to minimize thermal disturbance when placing fills and foundations in permafrost regions.

La moitié environ de la superficie totale du pays est occupée par le pergélisol, un terrain qui reste toujours gelé en profondeur, et comme le Canada se développe vers le nord, cette particularité du sol doit être prise en considération. Le présent Digeste décrit brièvement le pergélisol et ses traits caractéristiques, et traite des questions touchant le genre de fondations convenables dans les régions où il existe.

This report consists of a complete reproduction of the field notes of the authors made while they participated in the survey for the new site for the town of Aklavik during the summer of 1954.

This paper describes the fabrication of a complete thermocouple assembly. Elements of construction and installation are discussed under the headings thermocouple current, fabrication, switch box fabrication, field installation of the cable and temperature readings. The principle of measurement is that the emf generated between a reference junction of known temperature and one of unknown temperature can give the unknown temperature. The two metals used are copper and constantan, and the wires must be protected electrically from short circuits. Twenty gauge duplex wire individually encased in polyvinyl chloride is satisfactory. The wires from the installation are usually terminated in a weatherproof switch box. Leeds and Northrup rotary switches, type 31-3 are used. Simple clamp type connectors and terminal blocks ensure positive connection. The copper wires are attached to rotary switches. The constantan wires are attached to a common constantan wire. The thermocouple cable's outer jacket is cut at the depths at which readings are required and the copper and constantan wires are soldered to give a thermocouple junction. The completed multi-wire cable is inserted in a suitable length of polyethylene hose. A lucite or brass plug seals the lower end. Steel switch boxes house the switches and wire connection from the elements and still provide accessibility for readings. The cable and switch box are filled with high quality transformer oil. Installation involves pushing the assembly into a bore hole or in the case of short cables, a test pit. Longer assemblies are usually lowered into bore holes with a 10-20 lb weight tied to the bottom. Finally the bore hole is backfilled so that no air pockets exist.

The purpose of this report is to make available a record of data collected by Permafrost Research Station personnel at this most suitable of the sites, East Three. The report is concerned mainly with soil and permfrost conditions. Information on other physical aspects of East Three is included because of its inter-relationship with the soil and permafrost condtions.

Roughly one-fifth of the world's land area is subject to permafrost, that is, perennially frozen ground. It is particularly important in the Soviet Union and in Canada, each of which has roughly half of its territory affected. Permafrost not only poses questions of great geophysical interest but presents the civil engineer with many exceedingly difficult problems. This article reviews the principles governing the distribution of permafrost and some of the ways of overcoming the difficulties.

Soils and soil conditions typical of the delta proper are described first. Most of this information was collected during 1953, but data obtained in succeeding years also are included. Soils information also is given on areas investigated on the western edge of the delta along the Husky Channel and farther north. On the eastern edge of the delta, detailed exploratory soil surveys for the Aklavik Relocation Project were carried out at two potential townsite areas approximately 35 miles east of Aklavik. Notes on soils at Kittigazuit and in the Caribou Hills, are also included. Wherever it may prove helpful, soil information is augmented by typical aerial photographs, borehole logs, and ground photographs.

About one half of the total land area of Canada is underlain by perennially frozen ground, more commonly known as permafrost, and as development moves northward consideration must be given to this feature of the terrain. This Digest briefly describes permafrost and its characteristics and discusses problems related to foundation design in permafrost areas.

While permafrost provides excellent bearing for structures, it may lose its strength to such an extent that it will not even support light structures when thawed. Differential settlement is normal and usually results in serious damage or building collapse. Pile foundations were used extensively at Inuvik, NWT, an area of continuous permafrost to depths of over 300 ft. The use of piles at Inuvik was a suitable foundation type for the majority of buildings and facilities., Permafrost International Conference, 1966

This report summarizes the soils and permafrost data of the potential site bordering the West Channel on the west side of the Mackenzie Delta.

This report was prepared to record and describe the scope of the research program and the details of the instrumentation designed and installed at Kelsey Generating Station to assess the thawing effect of water on the performance of dykes constructed on perennially frozen ground. The predominant soils at Kelsey are stone-free lacustrine varved "clays" composed of rock flour. Perennially frozen ground was encountered in many of the exploratory holes. The active layer was 1-3 ft in low areas and 6-7 in higher ground. Permafrost was found to a depth of 35 ft. Extensive ice lensing had occurred in the varved clays from a thickness of hair-line to 8 inches. Ground temperatures in permafrost measured to depths of 20 ft in undisturbed ground varied from 30.5 to 3l.5 degrees F. The instrumentation consisted of ground temperature installations using thermocouples in nearby undisturbed ground, underneath the dykes and in the flooded zone. To measure possible dyke movements settlement gauges were installed.

Main factors hindering construction in arctic and subarctic regions are access problems, limited transportation facilities, a severe climate with long periods of cold and darkness, and the dominating feature of the terrain, permafrost. Emphasis must be placed on careful planning and the compilation of pertinent information prior to conducting field investigations. Air photos provide a valuable aid for preliminary planning and site evaluation. Field investigations involve an exploratory survey over a wider region to assess general site conditions; investigations that follow are to gather detailed information about permafrost which will directly affect the design and construction techniques to be used. Some thought should be given to continuing and expanding observations begun during the field investigations. Observations such as ground temperatures, depth of thaw in undisturbed and disturbed locations and effects of changing drainage patterns will provide valuable information for other projects in the area. Studies should continue using instrumentation and observations of the performance of the structure and its effect on the underlying permafrost., Permafrost International Conference, November 1963, Series: Technical Paper (National Research Council of Canada. Division of Building Research); no. DBR-TP-234