Механика мерзлых грунтов общая и прикладная

Ц ы т о в и ч Н.

А. К вопросу расчета фундаментов сооружений, возводимых

на вечной мерзлоте.

Научно-исследовательские работы Гипромеза, вып. 2, 1928.

Ц ы т о в и ч

Н.

А.,

В о л о г д и н а И. С. [и др.]. Лабораторные исследова­

ния механических свойств мерзлых грунтов. Сб. I и II, СОПС АН СССР, 1936.

Ц ы т о в и ч

Н. А.,

С у м г и н М. И. Основания механики мерзлых грунтов.

Изд. АН СССР, 1937.

Исследование деформаций мерзлых грунтов, (ч. II док­

Ц ы т о в и ч

Н.

А.

торской диссертации). Ленинград, 1940.

пластических деформаций

Ц ы т о в и ч

Н.

А.

1.

Исследование упругих и

мерзлых грунтов. Лабораторные исследования механических свойств

мерзлых

грунтов. Сб. I. Изд. АН СССР, 1936. 2. Некоторые механические свойства вечно­

мерзлых грунтов Якутии. «Труды КОВМ АН СССР», т. X, 1940.

Ц ы т о в и ч

Н.

А.

Расчет осадок фундаментов. Стройиздат, 1941.

Ц ы т о в и ч

Н.

А.

К теории равновесного состояния воды в мерзлых грун­

тах. «Известия

АН

СССР»,

серия «Географическая

и геофизическая»,

№ 5—6,

Ц ы т о в и ч

Н.

А.,

С а л т ы к о в Н. И.

[и др.]. Фундаменты

электростан­

ции на вечной мерзлоте. Изд-во АН СССР, 1947.

мерзлых грунтов.

Изд-во АН

Ц ы т о в и ч

Н.

А.

Принципы механики

СССР, 1952.

Н.

А.

Влияние условий замораживания на пористость водона­

Ц ы т о в и ч

сыщенных песков. Сб. «Вопросы геологии Азии», т. 2. Изд. АН СССР, 1955.

Ц ы т о в и ч

Н. А.

Вопросы теории механики грунтов при

строительстве

ской АН», т. XIX, вып. 1—3, 1956.

сил

сцепления связных глинистых грунтов

Ц ы т о в и ч

Н.

А.

Исследование

по методу шариковой пробы. «Труды Чехословацкой АН», т. V, № 3, Прага, 1956.

Ц ы т о в и ч

Н.

А.,

Н е р с е с о в а

3.

А. О физических явлениях и процес­

ча». Изд. АН СССР, 1957.

Ц ы т о в и ч

Н.

СССР, 1958.

Н.

А.,

В о т я к о в

И.

Н.,

П о н о м а р е в

В. Д. Методиче­

Ц ы т о в и ч

ские рекомендации

по исследованию

осадок

оттаивающих

грунтов.

Изд. АН

СССР, 1961.

Н.

А.,

Х а к и м о в

X. Р.

Применение искусственного

замора­

Ц ы т о в и ч

живания грунтов в строительстве и горном деле. Сб. «Доклады к V Международ­

ному

конгрессу

по

механике

грунтов»,

под

ред.

Н. А. Цытовича.

Строн-

издат,

1961.

Н.

А.

Нестабильность механических свойств мерзлых и оттаи­

Ц ы т о в и ч

вающих грунтов. «Труды I Международной конференции по мерзлотоведению».

США, 1963.

Н.

А.,

З а р е ц к и й

Ю.

К.

[и др.].

1. О консолидации оттаи­

Ц ы т о в и ч

вающих грунтов. «Доклады к VI Международному конгрессу по механике грун­

тов»,

Стройиздат,. 1965.

2. Сб. НИИоснований, № 56. Госстройиздат, 1966.

Ц ы т о в и ч

Н.

А.,

3 а р е ц к и й

Ю.

К. [и др.]. Прогноз осадок оттаиваю­

щих грунтов во времени. «Материалы V Всесоюзного совещания по обмену опы­

том строительства в суровых климатических условиях», вып.

5. Красноярск, 1968.

Ц ы т о в и ч

Н.

А.,

У х о в

С. Б.,

К р о н и к Я. А. Комплексные мероприя­

тия физико-химического

метода

борьбы

с

морозным пучением грунтов

насыпей.

механика грунтов», 1970, № 6.

Н. В., У х о в

С.

Б. Прогноз температурной

Ц ы т о в и ч Н.

А.,

У х о в а

устойчивости плотин

из

местных

материалов

на

вечномерзлых основаниях.

ла», 1968.

М.

Я. Деформации деревянных мостов от

пучин мерзлого

Ч е р н ы ш е в

грунта. «Железнодорожное дело» 1928, № 1—2.

мерзлых грунтов.

«Лабораторные

Ш е й к о в М.

Л.

Сопротивление сдвигу

Ш у й с к и й П.

А.

Основы структурного льдоведения. Изд. АН СССР, 1955.

Ш у ш е р и н а

Е.

П. К методике определения коэффициента оттаивания и

коэффициента уплотнения мерзлых грунтов при оттаивании. Сб. № 1 и 2

«Мате­

риалы по лабораторным

исследованиям мерзлых грунтов

под

руководством

Н. А. Цытовича». Изд. АН СССР, 1953, 1954.

поперечной деформации

и об

объем­

Ш у ш е р и н а

Е.

П. О коэффициенте

ных деформациях мерзлых грунтов в процессе ползучести. Сб. МГУ, вып. V, 1969.

Ш у ш е р и н а

Е.

П.,

Б о б к о в Ю.

П.

О влиянии влажности мерзлых

грунтов на их прочность. Сб. «Мерзлотные

исследования»,

вып.

IX.

Изд-во

МГУ, 1969.

SUMMARIES OF THE CHAPTERS

I N T R O D U C T I O N

In the Introduction the author formulates the general concepts

of

frozen

and

permafrost soils, and indicates the regions in which they are

found

and

their

principal properties leading to absolutely inadmissible deformations

of

structures

built on such soils (unless the necessary preventive measures

are

taken) up to

Based on a generalization of

a huge number

of

direct

determinations

of

the

content of unfrozen water in frozen soils, the principle

of

dynamic equilibrum

of

xvater and ice in frozen and permafrost soils is established. This principle

constitu­

tes the first law of frozen soil

mechanics and

is

formulated by

the author

as

follows: «The quantity, composition and properties

of

unfrozen

water

and

ice,

contained in frozen soils, do not remain constant, but vary with changes

in exter­

nal factors, being in dynamical equiliblium with these factors». Also treated of

are

the physical properties of frozen soils regarded as

a four-phase system of partic­

les, and interrelations of these

properties are established

(in Table

6). The chapter

This chapter is devoted to the problem of water

migration in

freezing

soils*

the prediction of the magnitude of cryogenic heaving

of

soils

and

the

neaving

forces developed in this process.

data

on

the

redistribution

of

On the basis of an analysis of experimental

moisture in. freezing soils

(natural soils and those artificially saturated

with

va­

rious cations), the motive

forces

of

migrationare

established

and

the

second

principle of frozen soil mechanics

is established.

It is

called

the

migration

prin­

ciple and states that: The migration of water in the freezing of wet soils is a mo­

lecular process of moisture

transfer, continuously

appearing

upon

any disturbance

of the equilibrium state of

the

soil phases

and upon

changes in

external actions

(the existence of gradients

in

temperature,

moisture

content,

pressure,

surface

energy of the mineral particles, velocity of the molecules in the water films, etc.).

Also discussed' are the methods of quantitative prediction of moisture accumu­

lation, due to its migration in freezing soils, and the cryogenic

heaving

of

soils

caused by this migration. On the basis of experimental data, the

order of

magni­

tude is established for the

normal

and tangential

forces

of

frost

heaving

in

soils

C H A P T E R III

Rheological processes in frozen soils

On the basis of

an

analysis of the

internal

bonds

in

frozen

soils,

and of

a study of the physical

causes leading to the development of

rheological processes

in them, as a result

of the initiation and extension

of

microand

macrofissures,

three stages of frozen and permafrost soil creep are discussed:

transient,

steady-

state (plasto-viscous flow) and progressive creep.

given

for the stressed-strained

Equations, based

on experimental data, are

state

of frozen

and

permafrost soils in the stages

of

attenuated

and

undamped

creep

(including

plasto-viscous flow). A

procedure

is

discussed

for

determining

design strengths of permafrost soils.

significance of

frozen

and

permafrost

As a general conclusion, the special

soil rheology is established. Without a

knowledge of the laws of

this

rheology, it

is impossible to access

the deformative

and mechanical properties

of

such

soils.

C H A P T E R

IV

Strength properties of frozen soils,

and critical

strength

values

In this chapter, on the basis of

experimental data,

obtained mainly

from

investigations conducted

by the author

and his

colleagues,

the instability of

the

and

permafrost

soils

are

discussed

in detail. These characteristics include

the

compressive, tensile

and

shear strengths, adfreezing

strength

and

the

resistance

to failure by cutting. The quantitative dependence of these values

on

the

above-

mentioned factors (changes in phase composition, temperature, etc.)

is

established.

Extremely

simple

analytical

relationships are

given

for

determining

the

initial and limiting critical pressure

on frozen and permafrost soils

regarded

as

cohesive bodies. These relationships are based on the equivalent

cohesion

of

the

soil

(determined

in

a ball

test). Calculated values are compared

here with

the

experimental data.

Besides, the determination of the critical

pressures

for

permafrost

soils is

discussed, as these soils have full shear strength with

variable

parameters of fric­

Examples of strength calculations end the chapter.

C H A P T E R

V

Deformation of frozen soils at subzero temperatures

Three kinds of deformations of frozen soils at subzero temperatures are dealt

with: instantaneous (adiabatic and elastic), long-term

(compaction, damped creep

and

steady plasto-viscous flow) and progressive creep

(brittle and ductile failure).

soils

Such

detailed investigations of elastic deformations of frozen and permafrost

are

given here for the first time. Values

obtained

by

the

author are

set forth

tants on the composition and the subzero

temperature. The laminated stratification

of frozen soils is also discussed.

The substantial compressibility of subzero hightemperature permafrost soils is

pointed out. Concrete values of the total

coefficient of compressibility are given

in

Part

Two

is devoted

to the

application

of

the

laws

of frozen soil

mechanics

construction

practice.

These laws serve as the basis for establishing the scienti­

fic

fundamentals of the

stable state of various kinds of structures

on

permafrost

soils. Such Structures include

apartment

houses,

industrial

buildings,

highways

and hydrotechnical structures.

C H A P T E R

VII

Geocryological engineering investigations

of permafrost

soils

This chapter deals with the main problems and the volume

of

geocryological

investigations required at

the constructions site. The concept is given of an integra­

ted geocryological engineering survey of the

territories

under

construction.

The

programme of

field and

laboratory investigations

of permafrost

soils is

set

forth

necessary investi­

gations

(allowing them

in some cases to

be

restricted

only

to

the

determination

chapter ends with an outline of

a

programme for

stationary

observations at

geocryological stations. These are highly important in

accessing

permafrost soils

for the foundation bases of structures.

C H A P T E R

VIII

Temperature stability of permafrost soils

in

the

built-up

territory

factors affecting

the temperature conditions of the

buildings and structures are

classified as: general, local and specific factors.

of permafrost soils is accessed

The general

temperature stability of the strata

on the basis of

the heat balance according to the meteorological and geocryologi­

determining the formation of

thawing range is

established (from

the

Fourier

equation for steady heat flow). It is shown that

under heated

buildings

(of a

width several times as great as the active layer)

a thawing range will be formed

in all cases, and the frozen state of the base soil

can be conserved only by remo­

ving the heat that is continuously liberated by heated buildings.

soils

under

heated

An approximate solution

for the temperature

of permafrost

chart forms which are convenient to

apply in engineering practice.

The

last

section of this chapter

deals

with the temperature stability of dams

built of

local

materials under permafrost

conditions. The transient temperature

As a re­

sult of many years of research, an approximate engineering method

of

predicting

the temperature stability of such dams was developed

and checked

on

physical

models by researchers, under the supervision of the author.

The conducted research showed that to conserve the temperature stability of

dams, built of local materials on permafrost soils, it

is absolutely

necessary

to

provide a waterproof frozen core that can be artificially frozen

and thowed

as

required.

calculation

of

the

required

Given at the end of the chapter are data on the

The researsch in frozen soil mechanics, dealt

with

in

the preceding

chapter^

necessitated to substantiate methods of

construction

on

permafrost

soils,

finds

extensive use in designing bases and foundation.

zen

Firstly, on the basis of concrete data on the

mechanical properties of the fro­

soils and the geocryological conditions of the

territory being built up, as well

as

the temperature conditions of the

buildings

and

structures to

be

built

the

permafrost soils in the frozen state» or

«construction

with

the use

of

such soils

in the thawing and thawed states».

The present chapter deals with the

calculation

and

design

of

foundations

according to the first of these principles.

majority

of cases

(the only exceptions being small buildings in subartic regions)

is the

provision of

cellars that can be ventilated either in the winter or

all year

round.

A

method

(developed by the author) is given for determining the

area of

base in the frozen state. A more exact solution

of the same

problem, proposed by

Dr. G. V. Porkhaev is also given.

the

frozen state of the base soils..

Measures are discussed for intensifying

Up-to-date methods are set forth in detail

for

calculating

the bearing capacity

ends with practical

examples of the design and building

of

structures

according:

to the

principle

of

conservation of the frozen state of the

soil

bases.

C H A P T E R

X

Bases and foundations on thawing soils

Structures

can be built on thowing soils only under the

condition

that

the-

design settlements of the foundations upon the thawing of the permafrost soils

do

not

exceed the

limiting permissible values. The pressure exerted by the

structure

on

the

thawing

soils should also be within the design value. The

latter

may

be

taken

equal to

the initial critical pressure on the soil at the design parameters of

shear

strength

corresponding to the unconsolidated and

undrained

state of

the

thawing soils, i. e. at the natural density and

moisture content that the

soil

has

in thawing. Moreover, the value of the adopted design strength should be a

cer­

tain

fraction (approximately 0,5 to 0,7)

of the

limiting load

on the soil

which is

also

determined

(according to the formula of Prandtl, Berezantsev

or others)

for

the unconsolidated and undrained state.

the

overall

dimensions

of the foundations

and finally selecting

their

cross

sections

ning a thawing depth, it is chosen so that the average settlement and

the diffe­

rence in settlements of the thawing base are less than the limiting

permissible

sible deformability.

a

generalization of

industrial

The end of this chapter is devoted mainly to

experience and special research on the methods

of

carrying out earth

work in

building various kinds of structures on permafrost

soils. Especial attention is given

to

the earth work performed in building dams of

local materials under

conditions

of

permafrost soils.

P A R T

O N E

RESEARCH AND THEORY

F O R E W O R D ..........................

. .

. .

.

3

I N T R O D U C T I O N

(Difficulties

in

the

construction

of

structures

orr

permafrost soils; principal concepts and

definitions;

establishment

and

develop­

ment of frozen soil mechanics in the USSR; basic principles). .

5

Chapter

I. Nature

of frozen soils,

their

distinctive

features

and

physical

properties

22

§

1.

Frozen soils as multicomponent and multiphase

systems

of

interconnected

particles

22

§

2.

Principal components of frozen soils

23

§

3.

Special

features

of

the

freezing of the

pore

water

in

soils

28

§

4.

Characteristic regions in the phase transitions of water

into

ice, and the unfrozen water content in frozen soils

35

§

5.

Dynamic equilibrium

of

unfrozen

water

and

ice

in

frozen

soils

. ..

39

§

6.

Physical

properties

of

frozen

soils

45

§

7. Types

of

ice

in frozen

and

permafrost

soils

and their

signi­

ficance

51

Chapter

II. Migration

of

moisture

in

the freezing of

soils, and

the

forces

of frost

heaving

58

§

1.

State

of

the

art

58

§

2.

Moisture

distribution

in

frozen soils

61

§

3.

Motive

forces

of

migration

69

§

4.

The

migration

principle

78

§ 5.

Prediction

of

moisture

migration

and

frost heaving

in free­

zing

soils

74

§

6.

Forces of the frost heaving of soils in their

action

on

the

foundations

of

structures

80

§

7.

Methods

of

frost

heaving

prevention

and

control

99*

Chapter

III. Rheological

processes

in

frozen

soils

107

§

1.

The

internal

bonds

in

frozen

soils

107

§

2. Initiation

and

development

of rheological

processes

in

frozen

soils

111

§

3.

Rheological

equations

for

the

stressed-strained

state

of

fro­

zen

soils

117

§

4.

Stress

relaxation

in

frozen

soils,

and

their

long-term

strength

. .

124

§

5.

Determining

the

creep

parameters

of

frozen

soils

131