Groundwater in Civil Engineering

465 Pages·1983·8.893 MB·2-478\465

by  LÁSZLÓ RÉTHÁTI (Eds.)

Further titles in this series:
1. G. SANGLERAT, THE PENETROMETER AND SOIL EXPLORATION
2. Q. ZÂRUBA and V. MENCL, LANDSLIDES AND THEIR CONTROL
3. Ε. E. WAHLSTROM, TUNNELING IN ROCK
4. R. SILVESTER, COASTAL ENGINEERING, I and II
5. R. N. YOUNG and B. P. WARKENTIN, SOIL PROPERTIES AND BEHAVIOUR
6. Ε. E. WAHLSTROM, DAMS, DAM FOUNDATIONS, AND RESERVOIR SITES
7. W. F. CHEN, LIMIT ANALYSIS AND SOIL PLASTICITY
8. L. N. PERSEN, ROCK DYNAMICS AND GEOPHYSICAL EXPLORATION
Introduction to Stress Waves in Rocks
9. M. D. GIDIGASU, LATERITE SOIL ENGINEERING
10. Q. ZÂRUBA and V. MENCL, ENGINEERING GEOLOGY
11. H. K. GUPTA and B. K. RASTOGI, DAMS AND EARTHQUAKES
12. F. H. CHEN, FOUNDATIONS ON EXPANSIVE SOILS
13. L.HOBST and J. ZAJfC, ANCHORING IN ROCK
14. B. VOIGT (Editor), ROCKSLIDES AND AVALANCHES, 1 and 2
15. C. LOMNITZ and E. ROSENBLUETH, SEISMIC RISK AND ENGINEERING DECISIONS
16. C. A. BAAR, APPLIED SALT-ROCK MECHANICS. 1
The In-Situ Behavior of Salt Rocks
17. A. P. SELVADURAI, ELASTIC ANALYSIS OF SOIL-FOUNDATION INTERACTION
18. J. FEDA, STRESS IN SUBSOIL AND METHODS OF FINAL SETTLEMENT CALCULA-
TION
19. A. KÉZDI, STABILIZED EARTH ROADS
20. E. W. BRAND and R. P. BRENNER (Editors), SOFT-CLAY ENGINEERING
21. A. MYSLIVEC and Z. KYSELA, THE BEARING CAPACITY OF BUILDING FOUNDA-
TIONS
22. R. N. CHOWDHURY, SLOPE ANALYSIS
23. P. BRUUN, STABILITY OF TIDAL INLETS
Theory and Engineering
24. Z. BASANT, METHODS OF FOUNDATION ENGINEERING
25. A. KÉZDI, SOIL PHYSICS
Selected Topics
26. H. L. JESSBERGER (Editor), GROUND FREEZING
27. D. STEPHENSON, ROCKFILL IN HYDRAULIC ENGINEERING
28. P. E. FRIVIK, N. JANBU, R. SAETERSDAL and L. I. FINBORUD (Editors), GROUND
FREEZING 1980
29. P. PETER, CANAL AND RIVER LEVÉES
30. J. FEDA, MECHANICS OF PARTICULATE MATERIALS
The Principles
31. Q. ZÂRUBA and V. MENCL, LANDSLIDES AND THEIR CONTROL
Second completely revised edition
32. I. W. FARMER (Editor), STRATA MECHANICS
33. L. HOBST and J. ZAJÎC, ANCHORING IN ROCK AND SOIL
Second completely revised edition
34. G. SANGLERAT, G. OLIVARI and B. CAMBOU, PRACTICAL PROBLEMS IN SOIL
MECHANICS AND FOUNDATION ENGINEERING
35. L. RÉTHÂTI, GROUNDWATER IN CIVIL ENGINEERING
Developments in Geotechnical Engineering 35
GROUNDWATER
IN CIVIL ENGINEERING
by
LASZLO RETHATI D. SC. (TECHN.)
Institute for Geodesy and Geotechnics,
Budapest
Elsevier Scientific Publishing Company
AMSTERDAM—OXFORD—NEW YORK—1983
This book is the revised version of the original Hungarian
Talajviz a mélyépitésben, Akadémiai Kiado, Budapest
Translated by
MIKLOS BOSZNAY and PAL MAGYAR
Joint edition with Akadémiai Kiado, Budapest
The distribution of this book is being handled by the following publishers:
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for all remaining areas
Elsevier Scientific Publishing Company
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Library of Congress Cataloging in Publication Data
Réthâti, Lâszlo.
Groundwater in civil engineering.
(Developments in geotechnical engineering ; 35)
Translation of: Talajviz a mélyépitésben.
Bibliography: p.
Includes indexes.
1. Water, Underground. 2. Seepage. 3. Civil
engineering. I. Title. II. Series.
TC176.R4713 1982 624.Γ51 82-1 1362
ISBN 0-444-99686-9 (Vol. 35)
ISBN 0-444-41622-5 (Series)
Copyright © 1983 by Akadémiai Kiado, Budapest
All rights reserved. No part of this publication
may be reproduced, stored in a retrieval system, or transmitted in any form or by any means,
electronic, mechanical, photocopying, recording, or otherwise,
without the prior written permission of Akadémiai Kiado, Budapest
Printed in Hungary
PREFACE
Problems related to groundwater are of prime importance in hydrology and in
geotechnics. Yet, despite this, the two sciences have developed in relative isolation
both as concerns theory and practice.
Hydrology is concerned primarily with the forecasting of water levels, for
example during spring maxima, or those developing during the vegetation period.
The aims of geotechnics (dewatering of subsurface spaces, dewatering of excava-
tions, establishment of infiltration networks, change of physical characteristics with
water level, etc.) have directed its field of interest towards the forecasting of
the maximum and the construction of groundwater level; of water stages during
frost periods; towards the determination or the direction of flow; and the
most favourable time of construction from the point of view of dewatering.
Statistical investigations have shown that 80 percent of damage to buildings
due to geotechnical effects is connected with the position or fluctuation of
groundwater.
In Hungary, research was initiated in the mid-fifties to develop geotechnical
methodologies which were best suited to the methods of analysis and the tasks of
geotechnics. The research was greatly facilitated by the fortunate situation that a
dense network of drillings is available giving accurate information about some
characteristics of the groundwater (instantaneous water stages, direction of flow,
slope conditions, chemical composition, spatial location of the water-bearing layer,
etc.), at the very site of the planned project.
Increasing interest in the problems resulting from industrialization, the ever-
growing influence of man on the water regime, the already substantial time-series
from observation wells, the advent of probability theory and the use of computers
have meant that a fresh summary of the present stage of development is urgently
required. The solution of problems at a higher level calls, at the same time, for a
gradual convergence of the two sciences both as to concepts and to methods, and
for increased application of the scientific knowledge acquired in related sciences:
geology, pedology and meteorology.
Many examples are given in this book in order to foster the practical application
of theoretical and empirical methods. Some of these are based on observations
made in Hungary, but these can easily be adapted — with re-assessment by
probability — for other countries with different physical conditions. The reader
5
should bear this in mind, and concentrate on the overall general interrelations and
on the methods presented and discussed in this work.
Finally, I would like to express my grateful thanks to Elsevier Scientific
Publishing Co., and to Akadémiai Kiado, the Publishing House of the Hungarian
Academy of Sciences, the workers of the Printing House and to my colleagues
who translated the text for their valuable work associated with the publication
of this book.
LÂSZLO RÉTHÂTI
6
1. ORIGIN OF SUBSURFACE WATER
AND CLASSIFICATION
1.1. The origin of subsurface water
Man had observed long ago that water, an element so important to him, is
available not only above but also below the ground surface. Obscure and mystic
theories prevailed for thousands of years about springs erupting in mountains and
water seeping into caves. Scientific views have been developed only recently on the
ground of observations acquired with the help of modern technology.
VENDL (1968) and BISWAS (1965) have commented on ancient theories as follows:
According to THALES (7th century B.C.) it is the wind that forces the water of the sea
into the soil, from which it is lifted toward the ground due to enormous stresses
originating from the gravitational forces of rocks, ARISTOTEF.ES (4th century B.C.) was
at the point that a great part of subsurface waters is a produce of the local
condensation process of vapour but there are also springs originating from
precipitation seeping through the soil and accumulated in the caves. It was clear to
him that precipitation comes from water vapour lifted up by the sun from surfaces of
water stretching above the ground. He used the term "meteorology" for the first time
when discussing atmospheric phenomena.
MARCUS VITRUVIUS POLLio (1st century B.C.) was the first to have understood
correctly the hydrologie cycle. He wrote that the sun lifts up water from rivers and
sea, clouds are formed; the cloud is then dispersed by collision with the mountains
and its water content is precipitated. Groundwater and springs originate from this
source. The latter in such a way that precipitation percolates down to a layer
consisting of rock, ore or clay then along the layer up to the ground surface, L. A.
SENECA (1st century B.C.) wrote in his Questiones Naturales that according to his
observations in his vineyard, precipitation did not penetrate deeper into the soil
than 10 feet. He thought that water is produced from underground air masses due to
a pressure caused by the "big darkness". Droughts are straight consequences of
earthquakes that demolish underground corridors from time to time.
The theories developed during the Middle Ages and up to the beginning of the
modern times about the origin of underground water hardly coincide with the
scientific views of today.
According to DESCARTES (1596-1650) there existed a system of channels below the
ground fed by the sea. The internal heat of the Earth caused water vapour to
develop, which then condensed upon the cool arches of the caves, and was finally
forced upward through crevices. (He did not consider the whereabouts of the large
15
amount of precipitated salt which would necessarily accrue.) DAVITY supported this
theory by noting that the sea never inundated land. Around this time the "theory of
capillarity" was also developed, which provided an explanation of how water could
emerge from the deeper layers and reach the ground as a result of capillary
attraction (KIRCHER).
The Frenchman B. PALISSY (1510-1590) stated that springs were fed by
precipitation percolating down to the impervious layer, LEIBNITZ (1646-1716)
largely reiterated DESCARTES' theory.
The founders of modern hydrology were P. PERRAULT (1608-1680), who also
measured precipitation quantitatively, and E. MARIOTTE (1620-1684) who proved
that well-water accumulates from precipitation, and also that springs may be fed
from surface precipitation sources. (His ideas were developed further by DE LA
MATHERIE around the end of the 18th century.) Astronomer HALLEY can also be
mentioned in this controversy. He studied evaporation and stated in 1687 that there
is a close connection between evaporation and precipitation.
The ideas of modern hydrologists were not accepted by a number of scientists.
KEFERSTEIN stated in one of his publications in 1827 that water is a produce of the
Earth's "transpiration" or "metabolism", o. VOLGER'S condensation theory (end of
19th century) attracted a lot of attention. According to this theory, groundwater is
fed by vapour condensed inside the cold pores of the soil from external warm air
masses and not by precipitation. It is surprising that similar misleading views
existed even at the beginning of the 20th century.
Nowadays, a number of ideas prevail about the development of the Earth's water
resources; these may be grouped basically around two theories.
The earlier theory (which might today be called the classical theory) assumed that
available water resources composed a part of Earth's appurtenances from the
beginning. Around the end of the star-ages of our satellite, a solid surface layer
started to develop pierced often by materials and gases with extremely high
temperatures, primarily water vapour and carbon dioxide. These were dispersed in
the atmosphere, but after a certain time — when temperature dropped below a
critical level — the water vapour condensed and precipitated.
According to M. DE TURVILLE'S solar theory, the material (corpuscular) radiation of
the sun resulted in the solar wind bringing a great number of hydrogen atoms into
the vicinity of the Earth, where association with oxygen took place. This concept is
seemingly supported by two facts: (1) the amount of seawater existing today is of the
same order of magnitude as the calculated amount of solar water developed since
the Earth's beginning (the specific amount of the latter is 1-2 t/day), (2) at an altitude
of 60-66 km there is a clouding zone the origin of which is supposedly celestial.
TURVILLE'S theory did not exclude the possibility of origin according to the classical
concept, but assumed that the amount of surface and subsurface waters created in
that way is relatively small.
Regardless of the accepted theory, two types of water may be distinguished
according to origin and location: juvenile and vadose.
16
Juvenile water is stored in the form of vapour in the liquid magma. By piercing the
cool crust of the Earth during volcanic eruptions, it reaches the ground and starts to
condense (SUESS'S theory). Vadose water takes part in the hydrological cycle. (In
ancient geological ages it was also juvenile — with a terrestrial or solar origin.)
Vadose waters may be classified as:
— condensed water;
— infiltrated water;
— fossil water;
— effusion water.
Condensed water is developed if water vapour stored in the pores of the soil
becomes cooled. This may modify only the first floor of the aquifer although only
slightly due to the small temperature-gradient of the soil and to the fact that, in
general, the air of the pores is close to saturation. Its role in the heat- arid
waterhousehold of the soil and at the investigation of diurnal fluctuations of
phreatic waters are discussed in detail in Chapters 1 and 3, and Chapter 7,
respectively.
Infiltrated water penetrates into the soil through seepage from the ground surface.
Its importance is preponderant in engineering practice. It is the main feeder of the
first phreatic layer and of karstic waters; moreover — according to individual
opinions — even a considerable part of the deep water originates from surface water
seepage.
Fossil water was encaved in the pores during the time of development of soil
(rock) by precipitation, or it originated from the surface water in which the soil
(rock) was sedimented.
Effusion water (dehydrated water) was emitted by rocks hydrated at the surface
and later submerged to considerable depths while exposed to substantial heat. N. A.
GAUTIER'S experiments have yielded the following data: 1 kg granite effused 7-3 g and
1 kg basalt 16-8 g water, respectively, if heated in vacuum. This process may take
place only in those layers of the Earth where temperatures range between the boiling
point and the critical point (374 °C) for water.
Of the types of water described above, infiltrated water originating from present
day precipitation is of utmost importance in civil engineering.
It is not easy to answer the question when this subsurface water mass reached its
present location. By radioactive methods, the age of rocks can be determined with
sufficient accuracy: isotope 14C traces back to 70 thousand years, thorium to 300
thousand, and fluor to 50 million years (LANG 1968). However, the method is usable
for the determination of water-age only if it is proved unambiguously that the water
is fossil, i.e. it has remained at the same place since its origin. Recently, the deuterium
and tritium content of water has provided clues relating to age and origin (see
Section 2.2.5).
2 Réthâti 17
1.2. Sciences dealing with subsurface water
The hydrological cycle takes part in the atmosphere and the lithosphère. The
sciences which deal with subsurface water are, therefore, those which are involved in
the investigation of the laws of subsurface hydraulic processes and which seek to
understand the nature of phenomena connected with water in both the atmosphere
and below the ground surface.
First of all hydrology must be mentioned which was to cover all phases of the
hydrological cycle. (Some people think that hydrophysics, hydrochemistry and a
part of hydraulics should also belong to hydrology.) However, hydrology (technical
hydrology) in a strictly narrow sense involves the investigation of the water cycle
from ι he point of view of water management primarily, viewed in this way, it
embraces geohydrology, surface hydrology and hydrometeorology.
Owing to the fact that subsurface water and rock are related to each other,
consideration of groundwater also forms a part of geology, and its study is the
domain of hydrogeology.
Fig. LI. Interrelation of sciences dealing with subsurface waters
Pedology is concerned, among other things, with the physical characteristics of
soils and, further, with relationships between soil, water and plant biology. The
latter discipline is called hydropedology, and the former embraces colloid
chemistry, geochemistry and even petrology, which is a subdiscipline of geology. In
many problems hydropedology calls upon agrometeorology which is involved in
the investigation of atmospheric phenomena, the heat- and waterhousehold of the
soils and plant vegetation.
As is evident, the sciences mentioned so far are closely related to each other and
there is much overlapping and common areas of interest (Fig. 1.1).
18
For the sake of completeness, hydrogeography should also be mentioned. This new branch of the
geographical sciences is concerned with the qualitative relationships of surface and subsurface waters.
Among the supplementary and auxiliary sciences the most important are:
— physics, primarily fluid-mechanics (hydromechanics), discussing the laws of
static and dynamic waters, and its applied aspect — more or less abstract — called
hydraulics;
— chemistry, primarily geochemistry and hydrochemistry, which deal with the
soil and the chemical composition of water, respectively;
— mathematics (which, more recently, includes mathematical statistics);
— hydrometry, for the measuring of hydrological characteristics (stage,
discharge, water-depth and velocity, etc.) and hydrography for data collection,
processing and dissemination and for the determination of empirical relationships
between the elements of the water regime.
With overlapping areas of interest, soil mechanics or — in a broader sense —
geotechnics may be added to the list. Soil physics, belonging to this subject, is closely
related to pedology, petrology, rock mechanics and colloid chemistry; it extends its
activity beyond soil-water interactions, toward the consideration of several other
hydraulic problems (seepage coefficient, capillary fringes above the phreatic level,
etc.). In the solution of technical questions, the position and characteristic
parameters of phreatic waters (expected fluctuation, direction of flow, chemical
composition, etc.) must be determined and later evaluated by geohydrological
methods.
1.3. Classification of water in the soil
Several researchers have tried to classify the different types of water observed in
the soil; however, there is no generally accepted method as yet. The aspects of
classification are as follows:
a) origin of water;
b) physical, chemical, biological characteristics;
c) forces affecting water;
d) hydraulic characteristics;
e) relation to plant vegetation.
As far as origin is concerned, two main groups may be distinguished.
1. Water created together with material and removable only by heat. This
comprises two types:
— constitutional water, OH " (hydroxil) ions attached to metallic or non-metallic
elements in a crystal lattice. During heating accompanying water deduction,
oxidation also takes place;
— crystal water, which is present in the structure of the crystal lattice as H 0. If
2
heated, it disappears accompanied by a transformation of the crystal lattice.
2. Juvenile or vadose water (see Section 1.1) completely, or partially, filling the
pores of the soil.
2' 19