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Principles of Geocryology (Permafrost Studies). Part II, Engineering
Geocryology. Chapter XIII, New and Immediate Problems in
Engineering Geocryology. p. 348-357
Saltykov, N. I.
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PREFACE
This translation is the twelfth from the Russian permafrost publication "Principles of Geocryology", Part II (Engineering
Geocryology). Chapters of Part II that have already been
trans-lated and the TT numbers in the NRC series of technical translations are (in the order of their translation) as follows:
Chapter I Chapter VII Chapter II Chapter VIII Chapter IX Chapter XI Chapter III Chapter IV Chapter V Chapter VI Chapter X
Principal aspects of engineering geocryology by N.I. Saltykov (TT-1215)
Particular aspects of mining in thick permafrost by V.P. Bakakin (TT-1217)
Deformation of structures ｲ･ｳｵｬｴｩｮｾ from freezing and
thawing by A.I. Dement'ev (TT-1219)
Beds for roads and airfields by G.V. Porkhaev and A.V. Sadovskii (TT-1220)
Underground utility lines by G.V. Porkhaev (TT-1221) Specific features of the maintenance of structures in permafrost conditions by A.I. Dement'ev (TT-1232) Basic mechanics of freezing, frozen and thawing soils by N.A. Tsytovich et al. (TT-1239)
Thermal physical principles of controlling the inter-action between structures and frozen soils by
G.V. Porkhaev (TT-1249)
Principal methods of moisture-thermal amelioration of the ground over large areas by V.P. Bakakin and
G.V. Porkhaev (TT-1250)
Bases and foundations by N.I. Saltykov and G.V. Porkhaev (TT-1266)
Use of ice, snow and frozen soil in engineering structures by K.F. Voitkovskii and M.M. Krylov (TT-1267).
This translation of Chapter XIII by N.I. Saltykov is the last
chapter of this volume on engineering geocryology. It begins by
listing currently existing gaps in engineering research and practice
related to permafrost problems. New problems arising in controlling
the thermal and mechanical interactions between engineering structures
and the ground in permafrost regions are discussed. The chapter
con-cludes with a plea for improving the dissemination of the results of permafrost investigations to those involved in construction projects.
This chapter was translated by Associated Technical Services Inc., East Orange, New Jersey, U.S.A., for the U.S. Army Cold Regions
and Engineering Laboratory, Hanover, N.H., U.S.A. The Division of
Building Research is grateful to this agency for permitting the National Research Council to issue this translation in its technical translations series, and to Dr. R.J.E. Brown of this Division who checked the translation.
Ottawa March 1967
N.B. Hutcheon Assistant Director
Title:
Author: Reference:
Technical Translation
1276
New and immediate problems in engineering geocryology
(Novye problemy i blizhalshie zadachi inzhenernoi geokriologii) N.I. Saltykov
Principles of geocryology (permafrost studies), Part II, Engineering geocryology, Chapter XIII. Academy of Sciences of the U.S.S.R. Moscow
1959.
p.348-357
(Osnovy geokriologii (merzlotovedeniya), Chast' vtoraya, Inzhenernaya geokriologiya, Glava XIII. Akademiya Nauk SSSR. Moskva
1959.
s.348-357)
NE\oJ AND IMfo.IEDIATE PROBLEMS IN ENGINEERING GEOCRYOLOGY
1. Lagging areas in current engineering geocryology.
2. New problems in controlling thermal interaction between
struc-tures and the ground.
3.
New problems in mechanical interactionbetween structures and the ground.
4.
Complex problems inengin-eering geocryology.
5.
Other problems in engineering geocryology.1. Lagging Areas in Current Engineering Geocryology
The contents of the preceding chapters of this volume indicate that sub-stantial progress has been made in various areas of engineering geocryology
during the past 25 - 30 years. Nevertheless, as a whole, this science still
fails in many ways to meet the requirements of modern industry, as was also noted in resolution of the 7th Interdepartmental Permafrost Conference in
1956.
Consequently, the authors of this volume recognized the necessity, in the concluding chapter of their work, of presenting the principal general problems and certain points on specific questions requiring an immediate andcorrect solution. In advancing these problems it was found necessary to
anti-cipate the chief practical reqUirements and to work with internal, historically constituent, but thus far not sharply defined, relationships in the develop-ment of engineering geocryology itself, and at the same time to consider the possible means for resolving the problems advanced.
Before enumerating these problems, it appears expedient to point out the principal gaps in engineering geocryology today, for with this knowledge it
is easier to identify problems for future investigations. In our opinion
such gaps include the following.
(a) Lack of specifications for construction in frozen ground under complex
permafrost conditions. Current and officially recommended methods of ensuring
strength and stability of structures have, as a rule, been developed for application in the simplest natural conditions, characterized by homogeneous geologic structure and temperature, and by the absence of substantial of groundwater flow or complex permafrost phenomena.
Construction procedure have not yet been developed for more complex
con-ditions. Such complex natural conditions from the standpoint of construction
include those of the so-called transition zone·, situated along the southern edge of this territory, with its typical discontinuous distribution of frozen
• The transition zone, according to Baranov, means the zone of change from a seasonally to a perennially frozen zone.
ground both vertically and horizontally at a temperature close to zero
(re-gions of the Vorkuta, Chernovka and Bureya coal fields, etc.). Construction
in the transition zone is difficult because the slightest disturbance of natural conditions of the heat exchange in one direction or the other brings with it marked changes in the state of the ground (transition from frozen to thawed and reverse), the first connected with settlement and the second with
heaving. In places, construction and mining in the transition zone are
complicated by the presence of groundwater (Southern Transbaikal region), accompanied by icings and large frost mounds hampering the performance of all underground work.
Coarse clastic (gravelly, pebbly) sediments saturated with ice encounter-ed in some valleys of the mountainous area of the Magadan region (Kalabin,
1956),
near Noril'sk (KOVM, Noril'sk brigade,1937),
in Petrovsk-Zabaikal'skii(Ushkalov,
1956)
are subject, contrary to common beliefs to considerablesettlement during thawing.
Construction on ice-saturated, coarse gravelly soils (flooded after a thaw) is also complicated because the physical, mechanical, and particularly thermal, properties of these soils differ substantially from the properties
of fine-grained soils like clay loam, sandy loam, and sand. No proper study
has been made of the vast lowlands adjoining the arctic seas (in the lower courses of the Lena, Indigirka, Yana, Kolyma, and other rivers) comprised of silty soils with widespread thick ice veins, solifluction, etc.
With the expanding economic development of permafrost areas more new
natural characteristics are being encountered for which there are likewise thus
far no reliable engineering solutions. These include the excessively deep
freezing of fractured rock strata in the region of the Chul'man deposits,
apparently reaching a depth of 8 - 10 m as a result of convective heat
ex-change, and the cryogenic changes of frozen sedimentary deposits of the
Vilyui Basin, under the influence of which these deposits lose their original properties of rock and are transformed into soil characterized by low bearing
capacity on thawing, notwithstanding their nominal
(15 - 25%)
moisturecon-tent (Tyutyunov,
1955).
(b) The inadequate state of knowledge of the problem of basic permafrost
phenomena, in spite of
25
years of investigation: the heaving of soils onfreezing and their settlement on thawing, including clarification of the nature of these phenomena, their effect on construction, and the development of
measures to take into account, eliminate, or control this effect. Without
resolving the problem of soil heaving and settlement, which the engineer encounters not only in areas with widespread permafrost but also in areas having seasonal freezing, and which is being actively investigated by scient-ists and manufacturers, no real progress can be achieved in the control of
-5-heaving and settlement.
(c) The primitive nature of some of the procedures in permafrost
engineering field investigations. Lately, in field studies of building sites
and road locations, permafrost engineering has begun to adopt such advanced methods as aerial photography, direct current electric surveys, and
ultra-sonic exploration. Radio engineering and radioactive elements are beginning
to be used for research purposes. At the same time, thermal and mechanical
properties of frozen ground frequently still continue to be determined, with-out consideration of the geocryologic structure, on small samples taken in the field more or less at random and not characteristic of the properties of large ground masses.
At the present time there is not even a method for determining indices for different physical and mechanical properties of soil characterizing its large volumes under natural conditions, outside of the first steps in the direction of determining the settlement of frozen soil during thawing
(Pchelintsev, 1951; and Zhukov, 1958a) and in the direction of determining the average diffusivity by analyzing the temperature field (Porkhaev, 1958).
(d) Insufficient link between the work of designers and the work of
industrial field and base laboratories. There are numerous circumstances
responsible for this serious shortcoming: (1) the independent development of individual divisions of geocryology: general geocryology, engineering geocryo-logy, and the physics and mechanics of soils; (2) the break between the
analysis of theoretical questions in the field of engineering geocryology, the development of official standards regulating construction and mining, and actual design and planning; (3) the complete lack of serious investigations of the economics of constructing and maintaining structures build in permafrost
｣ｯｮ､ｩｴｩｯｮｾ and the enconomics of mining in frozen ground, in particular the absence of investigations and instructions on the comparison of alternatives from the enonomic and engineering standpoints in selecting the most favour-able and suitfavour-able methods for ensuring stability (method of construction) of
structures to be erected in permafrost conditions. This situation, on the
one hand, frequently led and continues to lead project engineers to make unfounded decisions, causes them without evidence to substitute in design formulae values of soil properties borrowed from handbooks and random sources in the literature and, on the other hand, forces them to spend time in search-ing for data that could have been obtained from standards and literature with-out hampering the operation - for example, in determining the maximum load for
frozen ground or in determining the amount of unfrozen water in it. The
re-sults of such determinations usually remain in the records and are not used in projects.
(e) Insufficient analysis of many questions in designing structures for permafrost areas, questions that remain unresolved in spite of the presence of specialist organizations (Dal1 s t r o i p r o e k t , the design organization of Nori11
stroi, Giproarktika). These questions include: designing for the ultimate
situation in building conditions on frozen ground; standard design, standard construction; auxiliary tables and nomographs for calculations related to construction on frozen ground; general establishments for developing con-structive measures directed towards overcoming difficulties due to permafrost and applicable to various structures; industrial processes for performing earth work, etc.
Having examined the principal gaps in current engineering geocryology, we will pass on to the examination of new problems in the diffe.rent areas of
this field.
2. New Problems in Controlling Thermal Interaction
Between Structures and the Ground
The partial knowledge that we now possess of the relationship in the thermal interaction between structures and the ground in permafrost areas makes it possible to calculate and foresee with a certain degree of accuracy the thermal state and temperature of the ground, which serves as the surround-ings, foundation soils, and actual material of the structures and to control it to a certain extent.
However, the current understanding of these relationships is inadequate. For further improvement of measures for the engineering control of the thermal interaction between structures and the ground and of thermal action on the ground it is necessary to develop and deepen the theoretical principles of
heat exchange applicable to problems of engineering geocryology. The analysis
and generalization of the state of knowledge today in this area (Chapter IV) requires first and foremost a study of heat exchange relationships under the following conditions:
(a) In the atmosphere-ground system and in the atmosphere-structure-ground system on the atmosphere-structure-ground surface and in the surface layer of the atmosphere-structure-ground.
(b) Between the liquids and gases cirCUlating in underground mines, pipes, and conduits and the surrounding soil and rock.
Both categories of the problem are the most general and necessary for
solving many thermal problems in the situation under consideration. We will
explain their content and significance in engineering geocryology in greater detail.
(a) Heat transfer in the system ground and in the
ｾＭ
conditions of a region being prepared for development or building. It governs
the temperature field of the ground to a depth of 10 - 15 m and has a con-siderable effect on the temperature of all structures placed in the ground
to this depth. Unless this effect is taken into account, the solution of
problems involving the thermal interaction between structures and the ground takes on a doubly tentative character and often becomes completely inaccurate.
The main purpose of investigating heat transfer relationships in the system atmosphere-ground system is to achieve a more effective utilization of solar energy for thawing placer mineral deposits and for preparing natural
foundations under structures erected with preconstruction thawing. These
investigations, the essence of which is presented in Chapter V of this volume were initiated by P.I. Koloskov (1918) and later generalized. by V.P. Bakakin
(1955). In recent years they have been conducted by the Northeastern Division
of the Permafrost Institute and Dal'stroi.
Successes were achieved in the application of heat-transparent films (greenhouse effect) and by transferring solar heat by water during seepage,
drainage, irrigation, etc. Further investigations must pinpoint the role of
the individual components of the heat exchange, search out the reasons for the action on these components, and create a general theory on thaWing large
areas by means of ･ｦｦ･｣ｴｾｶ･ utilization of solar energy.
An important task is the search for those measures by which the thawing and warming of the ground by solar energy would not be of short duration but would fundamentally alter the permafrost conditions of the warmed areas, and would for a long time preclude the possibility of lenses and beds of perenni-ally frozen ground arising in them.
In connection with the adoption of construction with preconstruction thawing of the frozen ground it will be necessary to find rapid and effective artificial means of thawing in sections which are relatively limited in area
but complex in configuration. Besides the familiar methods of utilizing the
energy of steam and electricity, it is desirable to try the application of the ultrasonic method.
Besides striving to increase the efficiency of utilizing solar energy for warming the ground, the control of heat exchange in the atmosphere-ground system has long pursued opposing objectives as well, i.e. the preservation of ground in the frozen state and its cooling by means of the simplest measures
(clearing the ground surface of snow in winter, protecting it from the sun's rays in summer, etc.).
In recent years we have been faced with the problem of freezing large areas in order to prepare them for the sinking of shafts and the erection of industrial bUildings and liVing quarters in regions of transitional frozen
heat transfer research in the atmosphere-ground system to discover means of reducing the amount of absorbed heat and increasing its emission.
In investigating the heat transfer mechanism in the atmosphere-structure-ground system, the main objective is to reduce the depth of summer thawing of the ground under roads and airports, and reduce the amount of heat penetrating into structures and the foundation soils of structures erected with
preserva-tion of the frozen state of the ground (for example, dams). In the main, the
control of heat transfer in the atmosphere-structure-ground system is similar
in method to the control of heat transfer in the ｡ｴｭｯｳｰｨ･ｲ･ｾｧｲｯｵｮ､ system and
must be based on an investigation of the heat transfer components, their effect on the results of heat transfer, and the quest for methods for acting on these components.
One of the principal elements of the problem of investigating heat transfer relationships in the atmosphere-ground and atmosphere-structure-ground systems is the development of an apparatus giving a continuous record of the heat transfer components.
(b) Investigation of convective heat transfer mechanisms between liquids and gases moving in underground mines, pipes, and conduits and the surrounding
ground and rock. Knowledge of these relationships is essential for the
solution of a whole series of problems: (1) for establishing a system of
ventilation in mines penetrating perennially frozen rock to ensure the op-timum temperature for the air in mine shafts (Chapter VII); (2) for calculating heat losses of pipelines laid in frozen ground and serving to transport water, crude oil, and other liquids (Chapter IX); (3) for calculating the cooling capacity (amount of heat removed) of ventilated pipes and pipelines laid in the ground to freezing it and maintaining it in a frozen state, etc. (Chapter
VI). In some instances these problems are interconnected. For example, the
air temperature in mine shafts cannot be viewed separately from natural geo-thermal and hydrogeological conditions in the field, nor can the temperature regime around the shafts be viewed separately from the heat liberation of underground passages, which, as a rule, intersect in various directions the territory where the shafts are located, or from the heat liberation of surface
structures. Altogether, we are faced with the problem of complex heat physics
of establishing an optimum heat exchange and temperature field in the shaft
and on the surface of the shaft field. Without its correct solution it is
impossible to ensure stability of shaft construction or convenience of main-tenance.
To date the temperature-moisture conditions and the method of ventilating mine shafts have been studies only as they applied to shafts penetrating un-frozen rock.
As for heat losses taking place in the transportation of liquids and
gases, that question is even more complicated since pipelines are usually laid near the ground surface and feel the effect of air temperature fluctuations.
-9-Attempts have been made at a partial solution of this problem with respect to certain categories of pipelines and for the simplest conditions. In them, the basic questions of heat losses were solved either empirically
(Chernyshev, 1925), or on the basis of well-known idealized assumptions - in particular, the assumption of steady state thermal conditions and a simplified understanding of the temperature at the contact between liquid (gas) and the
ground. Unsteady state thermal conditions, which are unavoidable, for
example in the upper ground layer, and especially in the presence of un-steady state hydraulic conditions during the emptying and subsequent filling
of pipes, were not considered at all. The primary permafrost problem is the
development of a sufficiently satisfactory general method for determining heat losses and heat absorption by underground mines, pipes or conduits with a consideration of transient temperature conditions and phase transformation
of the mositure in the ground. In particular, it is essential to resolve the
question of the relative advantages and disadvantages of the method based on the solution of Forkhgeimer and the method of M.Ya. Chernyshev and to establish the sphere of application for both.
Specific problems in controlling the thermal interaction between
struc-tures and ground are extemely numerous. Among these we will note the most
urgent.
(1) All possible expansion of construction with preservation of the frozen ground beneath heated structures, since this is the simplest and most reliable means of ensuring the stability of structures erected on frozen ground containing a large number of ice inclusions.
To this end the development of simple and reliable means of preserving
the frozen ground will be required: (a) at construction sites characterized
by a deep lying or discontinuous permafrost at a temperature close to zero,
and (b) in the foundation soils of structures where the floor is laid
direct-lyon the ground and even with some excavation into the ground in the building of cellar rooms, (c) at the sites of contemporary commercial buildings equipp-ed ｜ｾｩｴｨ a variety of pipelines and underground passages, sometimes at quite high temperatures.
It is necessary to utilize and generalize available examples of success-ful solutions of similar problems in practice at Yakutsk, Noril'stroi, and Dal'stroi, and to create a theory of construction with preservation of the
frozen ground in unfavorable permafrost and hydrogeologic conditions. This
theory should include the development of M.M. Krylov's proposal on the use of " z er oters," i.e. containers filled with frozen cryohydrates melting at a
temperature of -8 to _10°, as well as investigating possibilities of
manipula-ting the heat content of the ground in time and space. Here we have in mind
absorbent material (peat, moss, etc.) saturated with cryohydrate solutions
and frozen in the winter. In the summer such frozen masses, connected with
the foundation of the structure by a ventilation system, can serve as absorbers for heat given off by the structure, thereby maintaining the temperature at
a sufficiently low level. Only the idea of this measure is formulated here.
To date it has not been implemented or checked in practice but could theoreti-cally become a prospect.
(2) The final solution of the question of the possibility and
practi-cality of building dams of frozen ground in permafrost conditions with main-tenance of a perennially frozen core and foundation soils, by means of natural cooling without the application of refrigeration plants.
In solving this problem, questions will have to be answered on: the
seasonally changing heat exchange between the frozen core and the foundation soils of the dam, on the one hand, and the relatively warm mass of water in the reservoir on the other; the theory and practice of the freezing of ground-water sometimes seeping through at a high rate; the percolation of ground-water
through the coarse-grained frozen ground with a high and sustained head; the possibility of erecting dams and other earthworks by bUilding them up layer by layer and freezing each layer as it is applied.
(3) The method of thermal calculations, although it has recently received
some development, still needs additional work. At the present time the
de-mands that must be placed on this method are clear: the emission and
absorp-tion of heat during changes in the phase composiabsorp-tion of the moisture in the ground must be taken into account; the dependence of the basic thermal pro-perties of the soil - conductivity, diffusivity, and moisture conductivity*, specific heat capacity, geothermal gradient, and the content of thermally active moisture - on temperature and, consequently, on coordinates and time must be taken into account; practical experience confirms the necessity of
* Translator's Notel This factor, termed "moisture conductivity" or "potential
conductivity" by the Russians, is defined by the relation aPi nt
aw
,
v z
where k
m
=
migration coefficient (Buckingham, 1907), yw= unit weight of water,Yo :: unit weight of ground, Pint
=
"internal" pressure, and w :: moisturecon-tent. The term "potential conductivity" is also used to mean the
proportion-ality factor in Buckingham's law, written in the form
= -
kpot2!.
dz
-11-taking into account the heat transported by the air and moisture filtering
through in coarsely fragmented and fractured ground. The practicality of
taking into account the heat carried by migrating moisture in fine-grained soils is less clear and requires clarification.
It is imperative to develop new methods for thermal calculations:
analytical methods relying on modern mathematical accomplishments, performed by means of model studies and the development of theories on simulating heat transfer in engineering geocryology (particularly by solving problems on the hydrointegrator in dimensionless quantities), performed on high-speed
elec-tronic computers. Complex mathematical solutions must be reduced for simple
application with the aid of nomographs, graphs, and tables accompanied by
illustrative examples. It should not be forgotten that at the present time
there is not a single work which could serve as a guide for the engineer in making calculations connected with the freezing and thawing of the ground.
3.
New Problems in Mechanical InteractionBetween Structures and the Ground
Mechanical interaction between structures and the ground is controlled on the basis of studies of relationships which govern stresSes and deformations in frozen, freezing, and thawing ground at the contact with the surface of a
structure and in the region over which the stresses, extend. Stresses and
deformation arising in the ground on interaction with a structure are inade-quately studied and their relationships should be investigated further with consideration of the state of the ground, type of structure, nature of the
external load, etc. Of special significance in future investigations is the
state of the ground, on which the mechanical interaction between structure and
ground depends and changes qualitatively. Thus, it is necessary to investigate
the following:
(1) Mechanisms of the distribution of stresses and their change with time in frozen masses intersected by mine shafts and near the surface of
foundations and piles placed in permafrost. Corresponding to these
relation-ships, new designs must be developed for structures to assure the best utiliz-ation of the strength properties of the material, and new, more advanced
methods for calculating their strength. As one example of practical
utiliza-tion of the results of research on the mechanical interacutiliza-tion between frozen ground and the foundation, one can consider the recently suggested use of
light piers to replace heavy foundations in the form of columns with pedestals. Light piers are more suitable and less difficult to manufacture.
It is necessary to pay special attention to: (a) establishing ultimate
which the foundations are placed in them; (b) taking into account the hetero-geneous nature of frozen ground both in permafrost engineerinB research and in calculations related to their strength and stability; (c) determining the rheologic properties of frozen ground for consideration of soil creep in bUlk, in design formulae, without taking samples.
In a number of cases there is great significance in the consideration of
､･ｦｯｾｮ｡ｴｩｯｮ in frozen ground, for example, with a large content of ice in-clusions and at a temperature close to zero, as well as in those cases when the frozen ground or ice is used as the construction material (Chapter X).
(2) Mechanisms of the interaction between structures and freezing ground in which the determining factors are the forces of heaVing and displacement of
the heaving ground. First of all it is necessary, as pointed out above, to
investigate the nature of the migration process occurring with the freezing of the ground and a method of reducing its intensity; to investigate the tangen-tial and normal stresses arising in the action of the heaving ground on the structure and the methods for reducing these stresses; to develop a theory of structure formation and the dependence on it of soil settlement with thawing. In developing the problem of frost heaving, special attention will have to be paid to the experimental technique, in which natural and industrial scales and conditions must be combined with the accuracy and care taken in
measure-ments made in modern-day physics and physical chemistry. One of the most
important elements of the experiment must be the remote observation of the movement of the combined and free moisture ·in the ground with freezing under natural and working conditions.
While continuing to utilize already known heaVing control measures (Chap-ters I and VI), it is necessary to search for new ones which would use and reflect current ideas on the mechanism of heaving and the interaction between
the heaving ground and the structure. Among the specific questions involved
in this problem, the following should be considered paramount: the
continua-tion of the quest for measures to reduce moisture migracontinua-tion in the freezing ground, the establishing of relationships for the distribution of tangential heaving forces on the surface of the structure and action on these forces aimed at their reduction; the determination of the possibility for mechanical counteraction of the normal heaVing forces acting beneath shallOW foundations with a determination of the magnitude of this counteraction; the determination of relationships for the mechanical action of heaving on pipes for
under-ground lines and cables laid in the seasonally freezing layer on sloping piles,
etc. In developing measures to combat frost heaving, it is necessary to
consider the processes of creep.
(3) Mechanisms of the mechanical interaction between structures and
-13-(a) the settlement of fine-grained and coarse-grained frozen soils with thawing under the action'of uniform and localized loading; the dependence of the settlement of fine-grained thawing soils on their structure; the tech-nique for calculating thaw settlement of soils to which the method using the compression curve obtained under laboratory conditions is inapplicable;
(b) methods and measures for improving the properties of the ground, being developed in two directions depending on whether an attempt is being made to improve the properties of the ground after thawing (Zhukov, 1958a) or prior to thawing, based on the possibility that chemical reactions take place in frozen ground, as demonstrated by I.A. Tyutyunov (1955);
(c) the technique for designing and constructing structures to be built on a thawing foundation on the assumption of their working together as a
single system. Particularly, it is necessary to pinpoint the role of the rate
of thawing and settlement of the foundation soils in the working of this sys-tem, as noted by V.F. Zhukov (1958a), as well as to determine the depth be-yond the limits of which the thawing of the frozen ground does not have any adverse effect on the strength of the structure.
It is necessary to continue the development of a theoretical basis for methods of construction design assuring the strength of rigid structures and frame-type structures with nonuniform thawing and settlement of the foundations soils.
It is necessary to conduct experimental-theoretical investigations on structures made of ice, snow, and frozen ground in order to develop methods for designing them.
4. Complex Problems in Engineering Geocryology
In the combined investigation of the mechanical and thermal interaction between the ground and structures and the application of the results of such an investigation in practice, comprehensive permafrost engineering problems
will arise. Problems having great practical significance include: (1)
con-struction on perennially frozen ground having a temperature close to zero; (2) construction on ice-saturated ground with thick inclusions of ice and on pure ice; (3) developing methods for designing footings and foundations on the basis of limiting conditions; (4) construction of pavements and earth beds for roadways and airports on perennially frozen foundation soils,
5.
other Problems in Engineerin$ GeocryologyBesides deepening and developing the theoretical principles of engineering geocryology applicable to the problems enumerated above, permafrost investi-gators are faced with many problems in a purely applied nature related to the
organization and mechanization of processes involving hard labour and to the development of special structures, as well as thermal insulation and sealing compounds made from local raw materials.
In terms of proper organization and special equipment for the production of different types of earthworks in frozen ground, builders are most of all in need of those used for roadbeds, dams, trenches, waterways; for passages, tunnels and shafts in frozen ground, in ice and snow; for the exploration,
excavation and underground development of useful minerals. In order to
in-crease the output in performing this type of work it is necessary to continue and develop the building of construction (excavation, transportation, etc.) equipment adapted to the conditions in areas of widespread permafrost.
Besides the equipment for doing earthwork it is necessary to create devices for laying underground lines and foundations, to improve special drilling tools for installing piles in frozen ground, etc.
It is necessary to develop rules for maintaining structures erected on permafrost.
With the development of areas having widespread permafrost, the need arises for creating for these regions special technical literature on footings and foundations, underground lines, earthwork, drainage work, on combating
icings, etc. To aid construction foremen and workers it is necessary to
develop technical specifications which must clarify questions of construction
and maintenance under these conditions. Technical literature intended for
schools of civil engineering and mining, polytechnics, research institutes and for manufacturers must be based on the natural conditions of their area. These properties must be regarded not from the standpoint of any special
features but as ordinary natural conditions. Builders and miners must be
trained in this literature in such a manner that the presence of permafrost at a certain depth from the surface would be for them an ordinary and usual event.
Technical texts, manuals, etc., published in the towns of this area must include a section containing instructions on the special features of certain structures outside the areas of widespread permafrost, just as in towns of the southern and western regions of the U.S.S.R.; technical books must be publish-ed in which, along with the usual construction rules, special features of
construction on frozen ground must be presented. Instruction in schools of
civil engineering located in permafrost areas should be conducted in a
corresponding manner. The first of these is the mechanical engineering
de-partment of Yakutsk University, with its specialists in exploration geology,
mining, and construction. It is imperative to create the first and best
school of engineering geocryology here. With the presence of the Northeastern
Division of the Permafrost Institute and of qualified engineering permafrost investigators in Yakutsk, this goal should be easily attained.
-15-Literature
Bakakin, V.P. Experience gained in controlling heat exchanges in the active layer of frozen rocks in order to increase the efficiency of mining operations. Izd-vo AN SSSR, 1955.
Chernyshev, M.Ya. Water lines in frozen ground. Vladivostok, 1925.
Kalabin, A.I. Permafrost studies in the development of the north-east. Sb. Dal'stroya, Magadanskoe knizhnoe izdatel'stvo, 1956.
Porkhaev, G.V. Determination of coefficient of heat conductivity of frozen soils from observation under natural conditions. Tr. in-ta merzlotov. AN SSSR, Vol. 14, 1958.
Tyutyunov, I.A. Cryogenet1c processes and their effect on the temperature of soil and rocks. Fondy in-ta merzlotov. AN SSSR, 1955.
Ushkalov, V.P. foundation ucheniya 0 1956.
Determination of pressure exerted by a foundat10n on thawing soil (experimental results). Sb. Materialy k osnovam
merzlykh zonakh zemnoi kory, No.3. Izd-vo AN SSSR, Moscow, Zhukov, V.F. Pre-construction thawing of permafrost below the foundation (a
new method of construct10n). Izd-vo AN SSSR, 1958-a.
ｔｲ｡ｾｳｬ｡ｴ･､ by
ASSOCIATED TECHNICAL SERVICES, INC. P.O. Box 271 East Orange, N.J.
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Maximum depth of permafrost in m. Soil isotherms at 1-2 m under nat-ural characteristic conditions.
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Boundarl. of ｦｲ･ｾｵ･ｮｴ perennially frozen 'islands'.Hinimum ground temp. at depth where annual variations stop (for values in mountainou. regions). Permafrost boundary. ｾＺＱｉ ｾ r---:::l ｾ
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-- 78 U.S.S.R. 1956 by 1.Ya, Baranov3?O ? apo SpOII" I'>, . o f · • • • " " I " "I
1. Arctic Ocean; 2. Barents Sea; 3. Kara Sea; 4. Laptev Sea; 5. East Siberian Sea; 6. Vorkuta; 7. Igarka; 8. Verkhoyansk; 9. Anadyr; 10. Bering Sea; 11. Okhotsk; 12. Sea of Okhotsk;
13. Petrozavodsk; 14. Leningrad; 15. Ta11in; 16. Riga; 17. Vilnius; 18. Minsk; 19. Kiev; 20. Kishinev; 21. Moscow; 22. Tbi1isi; 23. Erevan; 24. Baku; 25. Ashkhabad; 26. Sta1inabad;
27. Sverd1ovsk; 28. Tashkent; 29. Frunze; 30. A1ma-Ata; 31. Omsk; 32. Novosibirsk; 33. Krasnoyarsk; 34. Irkutsk; 35. Chita; 36. Yakutsk; 37. Khabarovsk; 38. Vladivostok; 39. Oimyakon.
