Earth Engineering: Perspectives, Principles, and Practices

By Murray Sarafinchin

Questions about the Earth continue to haunt engineers. For instance: What do we know about our ancient planet? How should we be using it? And what are the best technologies and strategies to sustain us?

Earth Engineering provides the background necessary to analyze these questions as well as perspectives, principles, and practices to guide your understanding of geoengineering problems. Scientists, engineers, regulators, designers, constructors, educators and students will find this book especially useful when considering challenges tied to civil engineering, construction, and mining. Written in simple language, this reference guide covers many areas, including

how the Earth began and developed over 4.6 billion years ago;

how the Earth began and developed over 4.6 billion years ago;
how to use site investigations to mitigate planning omissions and design errors;
how to cope with variable subsurface strata and building challenges;
how to approach geologic uncertainty and analyze problems on varying terraine;
how to handle environmental regulations and legal considerations.

You will treasure this broad collection and overview of geoengineering perspectives, principles, and practices. Enhance your knowledge and troubleshoot common problems with the knowledge, tools, and strategies you will fi nd in the extensive repertoire of topics and concise illustrations in Earth Engineering.

• Language: English
• Publisher: iUniverse
• Release date: Dec 27, 2010
• ISBN: 9781450275996

Murray Sarafinchin

MURRAY SARAFINCHIN is a Professional Engineer, a designated Consulting Engineer and an Honorary Geotechnics Specialist licensed in Ontario, Quebec and Barbados. Since 1984 he has served as President and Principal Engineer of Sarafinchin Associates Ltd. He has more than thirty five years of experience and has worked on more than two thousand engineering projects throughout the world. He is a guest lecturer. After graduating in civil engineering at the University of Western Ontario and working throughout Canada and internationally, he received his graduate degree in geotechnical engineering from the University of Waterloo.

Book preview

EARTH

ENGINEERING

Perspectives, Principles, and Practices

MURRAY SARAFINCHIN

iUniverse, Inc.

Bloomington

Earth Engineering

Perspectives, Principles, and Practices

Copyright © 2010, 2011 Murray Sarafinchin

All rights reserved. No part of this book may be used or reproduced by any means, graphic, electronic, or mechanical, including photocopying, recording, taping or by any information storage retrieval system without the written permission of the publisher except in the case of brief quotations embodied in critical articles and reviews.

iUniverse books may be ordered through booksellers or by contacting:

iUniverse

1663 Liberty Drive

Bloomington, IN 47403

www.iuniverse.com

1-800-Authors (1-800-288-4677)

Because of the dynamic nature of the Internet, any Web addresses or links contained in this book may have changed since publication and may no longer be valid. The views expressed in this work are solely those of the author and do not necessarily reflect the views of the publisher, and the publisher hereby disclaims any responsibility for them.

ISBN: 978-1-4502-7597-2 (pbk)

ISBN: 978-1-4502-7598-9 (cloth)

ISBN: 978-1-4502-7599-6 (ebk)

Library of Congress Control Number: 2010917405

Printed in the United States of America

iUniverse rev. date: 7/7/2011

Contents

Chapter 1

INTRODUCTION

Chapter 2

OUR EARTH

Chapter 3

GEOLOGY

Chapter 4

ROCKS AND MINERALS

Chapter 5

HYDROLOGY AND THE HYDROLOGIC CYCLE

Chapter 6

GEOTECHNICS

Chapter 7

SUBSURFACE INVESTIGATION

Chapter 8

SOIL CLASSIFICATION

Chapter 9

LABORATORY TESTING

Chapter 10

HYDROGEOLOGY

Chapter 11

GROUNDWATER

Chapter 12

ROCK ENGINEERING

Chapter 13

SOIL MECHANICS

Chapter 14

FOUNDATIONS

Chapter 15

SLOPE STABILITY AND LANDSLIDES

Chapter 16

EXCAVATIONS

Chapter 17

LATERAL EARTH PRESSURES AND RETAINING WALLS

Chapter 18

TUNNELS

Chapter 19

EMBANKMENT DAMS

Chapter 20

SOIL COMPACTION

Chapter 21

TRENCH EXCAVATION AND BACKFILL

Chapter 22

GEOSYNTHETICS

Chapter 23

PAVEMENTS, CONCRETE AND ASPHALT

Chapter 24

GROUND SUBSIDENCE

Chapter 25

GROUTING

Chapter 26

FROZEN GROUND ENGINEERING

Chapter 27

FIELD INSTRUMENTATION AND MONITORING

Chapter 28

GEOCONSTRUCTION QUALITY ASSURANCE

Chapter 29

GEOPHYSICS

Chapter 30

GEOCHEMISTRY

Chapter 31

MINING, PITS AND QUARRIES

Chapter 32

EARTHQUAKES, VOLCANOES AND TSUNAMIS

Chapter 33

GLOBAL WARMING, CLIMATE CHANGE

AND SOIL DEHYDRATION

Chapter 34

GEOENVIRONMENTAL ENGINEERING

Chapter 35

GEOENVIRONMENTAL SITE ASSESSMENT

Chapter 36

GEOENVIRONMENTAL SITE REMEDIATION

Chapter 37

GEOSCIENCES IN MEDICINE

Chapter 38

COMPUTER ANALYSIS AND MODELLING

Chapter 39

COMMUNICATION AND REPORTS

Chapter 40

INTERNATIONAL SYSTEM OF UNITS

Chapter 41

QUALIFIED PROFESSIONALS

Chapter 42

REGULATORY FRAMEWORK AND SAFETY

Chapter 43

LEGAL CONSIDERATIONS

Chapter 44

OUR EARTH’S FUTURE

Preface

Today we are fortunate to have university textbooks and library references to benchmark various aspects of geoengineering. These secure a wealth of detailed information on engineering geology, geotechnical and geoenvironmental engineering, hydrology, hydrogeology, mining, construction quality assurance, site remediation practices, and related topics. Despite this wealth of information, we habitually encounter earthworks and geoenvironmental problems during engineering, construction and mining projects. Problems may develop in the field from incorrect decisions made during the feasibility, planning and technical design stages concerning project specifications and plans, or from schedule and budget constraints during the construction stages. These problems are commonly of a basic, fundamental nature rather than due to more esoteric causes. This book addresses some of the day to day matters encountered in geoengineering. As such, this book is not about theories and formulae in geoengineering. This book uniquely offers a geoengineering collection with stimulating overviews and enlightening insights to our dynamic Earth transformations. It focuses our thinking to a perspectives, principles and practices approach to the investigation, design and construction challenges commonly encountered in earth engineering and environmental sciences.

These chapters transcend several basic and specialty subjects. Earth formation including soil, rock and groundwater components plus classification methods is presented. Various earth structures and ground subsidence are described. Some specialties are specific geotechnical problems such as expansive clays, collapsible soils, and freezing effects that cause distinctive problems in design, construction and service life. Included are helpful chapters on contamination and remediation, geotextiles, landfills, global warming, health, law and ethics.

The objective of this geoengineering sciences reference book is to provide perspectives, principles and practices to understand common geoengineering problems in civil engineering, construction and mining. The intended audience includes geologists, engineers, architects, contractors, developers, regulators, planners, earth scientists, educators and students who must plan, design, build and operate projects with geomaterials, provide drawings and specifications for the work, and then provide onsite engineering reviews that must optimize earthworks. A theoretical treatment of the issues is deliberately avoided, so prior education in mathematics, sciences and engineering is helpful, but not required to make use of this technical reference book.

Due to the uncertainties of earth evolution, including non homogeneous and anisotropic subsurface conditions as related to engineering, construction, mining and environmental sites, it is always best to set a conservative geoengineering course respecting any uncertainties affecting loss of equipment, property damages and most importantly human safety. Consequently, this reference book will be useful to scientists, engineers, contractors and quality control/quality assurance personnel working with geomaterials. Most projects today require integrated multidisciplinary teams, and it is felt this reference book will prove useful to specialist educators, planners, designers, constructors and practitioners who must work with applied geoengineering and environmental sciences as part of their tools. The student studying geology, civil engineering, architecture, construction, mining and environmental subjects will find this book useful as a guide to the geoscientific background, actual field problems and their solutions, and as a supplement to more theoretical academic studies.

Geoengineering technology is implemented daily to further mankind in the quest for knowledge and sustainable infrastructure development. It is professionally gratifying to be a part of this progressive industry. Hopefully, the perspectives, principles and practices provided in this reference book will assist novices as well as the experienced to build even more upon past experience and to reduce the errors that bring us to where we are.

Whether being more comfortable onsite solving problems for clients or in the office writing reports about them, or sparing time in university libraries the compilation of this book has required an extraordinary effort over many years. Discipline to complete the work has prevailed partly because of my dislike for the confusion created by special interests, a passion to have geoengineering showcased for the prime profession it is, and the fact that it is an essential and rewarding first step for sustainable development in all civil engineering, construction and mining sites.

The impetus to create this first book publication comes from within, and it is enhanced by valuable professional experiences. The uniqueness of such broad based subjects comes from the several and wide variety of Sarafinchin projects, and earlier assignments with Trow, Golder, and Monenco. The compilation of writings commenced with my role as a thirty year speaker for geoengineering seminars to the Ministry of the Environment and the Good Roads Association, plus my special lectures to universities, colleges and conferences. My explorations to Waterloo University, University of Western Ontario, Queens University, McGill University, University of Toronto, Columbia University in New York, Massachusetts Institute of Technology in Boston, University of Berkeley and Stanford University in California, Imperial College in London UK, Florida Atlantic University in Boca Raton, and natural science museums in the world gleaned numerous concepts, beliefs and achievements for this book. I am thankful for these opportunities. Similarly, I appreciate the assistance of my editors and publisher. I am indebted to industry leaders who inspired my early manuscript and later contributed helpful comments. My clients, fellow practitioners, educators, family and friends have been supportive. Time is precious in a consulting engineering office, and although library research and manuscript schedules fell behind, adding new chapter topics begot enlightenment and an amazing stimuli to get the book up and going. There is an addictive thrill in writing it. A variety of colleagues and peers graciously agreed to review and comment on specific portions of the manuscript, and I am grateful for their input.

Members of my staff, particularly my dedicated administrative assistant, are foundations to the preparations and illustrations. Their assistance is greatly appreciated. Any errors or omissions in the text are solely the author’s responsibility. A second edition will revitalize our thoughts.

Chapter 1

INTRODUCTION

All civil engineering and mining projects engage the surface of the Earth. The feasibility studies, planning, design, construction and operation of such projects are supported by or situated in the Earth’s crust.

We are fascinated with, but carefully reminded that every site used for civil engineering and mining structures is unique and nestled within a widely varying Earth terrain. There are often vast subsurface differences, or nonhomogeneous and anisotropic conditions, between adjoining sites due to the underlying and evolving geologic anomalies and the varying stratigraphy. Although site characteristics can vary, the fundamental geoengineering principles applied to the factual observations of the subsurface conditions do not vary.

The renowned engineering geologist, Dr. Robert F. Legget, advises us,

… the records of the geological survey show conclusively that closer cooperation between the geologist and the engineer would be greatly to the advantage of both, and it is a pity that there is no very direct way in which geologists could be kept informed of the progress of important excavations.

Within civil engineering the discipline of geotechnical engineering developed from the science of soil mechanics in the early part of the twentieth century.

The father of soil mechanics, Dr. Karl Terzaghi, stated,

…on account of the fact that there is no glory attached to the foundations and that the sources of success or failure are hidden deep in the ground, building foundations have always been treated as stepchildren and their acts of revenge for lack of attention can be very embarrassing.

and he has gone on to emphasize

…in earthwork engineering, success depends primarily on a clear perception of the uncertainties involved in the fundamental assumptions and on intelligently planned and consciously executed observations during construction. If the observations show that the real conditions are very different from what they were believed to be, the design must be changed before it is too late. These are the essentials of soil mechanics in engineering practice.

Both the science and the art of geoengineering are changing as many important advances are being made.

The purpose of the first edition of this engineering sciences reference book is to provide an overview of earth engineering and geoenvironmental sciences. It is organized by individual informative chapters with perspectives, concepts, principles, practices, examples, references and suggested further reading. The subjects are explained in simple terms and with nominal theory, formulae and mathematics. This reference book is intended for planners, developers, geologists, geoscientists, engineers, architects, contractors, regulatory agencies, investigators, practitioners, educators, students and interested parties. It embraces the wider specialist field of geoengineering as a marriage of geology and earth sciences with geotechnical and geoenvironmental engineering for civil works and mining applications.

This geoengineering reference book is introductory and an important checklist to the basic areas of interest, the terminology, the concepts, the investigative approaches and practical applications of geoengineering in civil infrastructure and mining projects respecting safe and clean environments for sustainable development. At the beginning of human life on Earth, there were few people, and nature seemed vast and endlessly self renewing. In 1900 almost two billion people on the planet lived mostly in rural village communities. We were agrarians, or farmers, who knew we must depend on and work with Earth’s natural processes. Only one hundred years later, in 2000, the global population has grown to six billion, and the number of cities with over one million people had increased to more than three hundred. Most people in industrialized countries live in large cities where it has become convenient to believe that our highest priority is the economy. At the same time, it is important to recognize that every single thing we consume comes from the Earth using geoengineering sciences and goes back to it as waste requiring geoenvironmental engineering solutions. Engineers and scientists in cooperation with owners and industries, are charged with the opportunities to create sustainable Earth developments using knowledge, experience, ingenuity, communication skills and nobler motives.

Chapter 2

OUR EARTH

Our Universe

Our universe or world is the whole of all existing matter, energy and space. From the beginning our ancient ancestors looked up into the night sky, and wondered, where did it all start? Religion has sought to provide us with some of these answers. At the same time a transition to science has developed rational thought to influence our understanding.

Religious Beliefs

The intent of this discussion is not to contradict the religious belief that the universe and the Earth within it were created by God, but to speculate and theorize, based on scientific findings and research by others, just how He made it happen.

In the Bible, Genesis 1:1-5 states that in the beginning God created the Heaven and the Earth. His world is in seven units, or seven days, as follows:

First day, creation of light

Second day, creation of heavens and water

Third day, creation of land and vegetation

Fourth day, creation of bodies of light

Fifth day, creation of creatures of heaven and waters

Sixth day, creation of life on land, vegetable food, and mankind

Seventh day, God rests from all work

Christian tradition has it that Moses wrote the creation story of our Earth along with the first five books of the Bible. The first five books of the Old Testament also comprise the Torah, the sacred scroll that is found in the Tabernacle of Jewish temple. Christianity considers Jesus as the son of God speaking as the Divine on Earth. However, from both the viewpoints of Judiasm and Islam, he is considered a prophet. In Judiasm, there is only one God and the prophets play a key role, and in Islam, there is also only one God and Mohammed is his prophet. Buddhism encourages that all problems on Earth be solved by overcoming greed, hatred and delusion. Hinduism believes in a reincarnation to Earth. Many other spiritual disciplines exist.

All cosmologies, or at least all early conceptions of the universe have a religious aspect. Many used symbolism, plus numerology, cosmology, and astrology thinkers such as Pythagoras, Plato, Ptolemy, Copernicus, and Galileo, while others relied on purely anthropomorphic tales of animal and family interactions

Scientific Reasoning

Cosmology is the study of the evolution and structure of the universe. Science estimates the age of our universe to be between 12 and 15 billion years old.

Cosmogony is the study of the origin of the universe. It probes if we are the only living creatures in this vast cosmos, or are there other beings out there?

In our universe there are many galaxies held together by gravitational attraction. Undoubtedly some have life supporting water and environments which are believed to have extraterrestrial beings different from Earth. If aliens secretly visit Earth, for which there is often reported evidence, then why do they appear to bypass us? Dr. Steven Hawking, the famous physicist, recommends that we do not try to communicate with aliens. Is this because these technologically super advanced beings have no special interest in us, in the same way that we walk through our forests, and neither stop to explore nor engage to interfere with the ants beneath our feet? Are advanced space travelers missing out on the human race in the same way we humans neglect ants, not knowing that genetic and molecular biology studies have shown that ants live in complex societies, they have a caste system, they go to war, they take slaves and they tend gardens on Earth.

Recognizing the 15 billion year age of the universe, the 4.6 billion year old Earth, the estimated 1.5 billion year presence of mankind, the scientific advancements that humans have made in only the past 100 years, and how much more there is to learn in science and engineering, perhaps our best current role is to continue collecting geoscientific knowledge and geoengineering experience for an effective future rendezvous in space?

Scottish geologist James Hutton (1790), one of the founders of earth science stated that geological investigation of Earth showed no vestige of a beginning, and no sign of an end. One of the great contributions to earth sciences is by Charles Lyell in his Principles of Geology (1830) suggesting that our Earth is shaped by constantly acting natural processes with a place for life in nature.

Many geoscientists accept some version of the big bang theory. At first all energy and matter was closely concentrated. About 15 billion years ago a vast explosion scattered everything through space. The Sun is believed to have come from an exploding supernova in our Milky Way Galaxy. Cosmologists believe the universe was over 10 billion years old when our solar system formed 4.6 billion years ago. The gravitational pull of the Sun caused elemental debris, or planetesimals, to orbit around it. Earth started as one of these planetesimals gaining mass and size as other planetesimals collided into it as it orbited the Sun. Each time an asteroid sized planetesimal collided with Earth, the tremendous impact created heat so intense that Earth’s surface stayed in a constant molten state. The entire Earth was covered by a sea of molten lava. Some researchers estimate the magma ocean to have been thousands of kilometres deep. The process of planetesimals crashing into each other to form planets is called accretion. Most of the planetesimals that orbited the Sun have accreted into planets and their moons. Consequently we are not in much danger of an asteroid hitting Earth and causing mass destruction. Planetesimals still fall to Earth, however most of them burn up in Earth’s atmosphere before reaching the ground. Seen in the night sky these shooting stars are meteors, and if they penetrate through Earth’s atmosphere hitting ground, then they are meteorites.

Thus our solar system comprises the Sun and the eight planets plus dwarf planets formed from a cloud of dust and gas spinning in space. The largest and most influential body is the Sun, a glowing ball of gases a million times the volume of Earth. The Earth’s radioactivity caused the surface to melt. Upon cooling molten rock layers formed the continents and volcanic gases formed the atmosphere. Water vapour condensed to make oceans. Earth is a revolving ball with a molten core and a rocky and water covered surface. Earth is one of eight planets along with minor planets and lesser moons, thousands of asteroids, billions of comets, uncounted meteorites, dust and gases orbiting the central star which is the Sun in our solar system. The planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto has relatively low mass, and recently it has been reclassified to a minor planet. Dwarf planets include Ceres, Charon and Eris.

As mentioned, accumulating mini planets, dust and gases formed the Earth about 4.6 billion years ago. Compression caused by gravity produced immense internal heat and pressure. The Earth’s molten surface cooled and hardened, but its interior is intensely hot. Oceans cover the majority of the Earth.

In space, Earth is a dense rocky planet, third closest to the Sun, and small compared with Jupiter and Saturn. While Earth tilts on an angle of 23.5 degrees and it rotates on its axis each day of 24 hours, it also orbits the Sun each year of 365 days, held in orbit by the Sun’s gravity. From space the Earth looks blue and calm, but under its oceans, deep beneath the crust, the Earth’s core is fiery and white hot.

An atmosphere of invisible gases mainly comprising nitrogen and oxygen surround the Earth. The crust of the rocky outer surface of Earth is about 6 km thick under oceans and up to 64 km thick under mountain ranges. The crust consists largely of granite under continents and basalt below oceans. The semi-molten mantle flows sluggishly between the crust and outer core. The dense molten outer core may be mainly iron and nickel with some silicon. The inner core has intense pressure and high temperatures of 3700 degrees C. From the Earth’s core, convection currents convey heat through the mantle to the crust.

The Earth has a diameter of 12,756 km. It has an equatorial circumference of 40,075 kilometres. The Earth has a mass of 5976 million million million tones. The Earth has a surface area of 510 billion square kilometres. The Earth is located 150 million km from the Sun. The Earth orbits the Sun at 29.8 km/sec. Oceans cover 71% of the Earth’s crust. Earth is a symmetric sphere because it bulges in the middle.

The most abundant elements in the Earth’s crust are oxygen (47%), silicon (28%), aluminum (8%), iron (5%), calcium (4%), sodium (3%), potassium (3%), magnesium (2%), and other elements. Heavier metals such as iron and nickel are formed in the core.

Gravity anomalies reinforce the theory of isostasy which describes a state of balance in the Earth’s crust where continents of light material float on a denser substance into which continental roots project like the underwater mass of floating icebergs.

The Earth’s crust is a floating mattress. It is a restless jigsaw puzzle of oceanic and continental plates coupled to a rigid slab of upper mantle. Heat rising from the Earth’s core and lower mantle are believed to produce convection currents that produce plate tectonics. Constructive margins are sub oceanic spreading ridges formed between two separating oceanic plates. Destructive margins are oceanic trenches where an oceanic plate dives below a less dense continental plate. Conservative margins are two plates sliding past each other. Active margins are where colliding continental and oceanic plates produce volcanic eruptions, earthquakes and mountain building.

The surface of the Earth’s crust receives significantly more energy from the Sun above than the hot molten core below. Sunshine warms the tropics more than the polar regions. This uneven heating creates belts of differing atmospheric pressure. Winds blow from high to low pressure. Winds drive ocean waves and surface currents spreading heat more evenly around the world. The Sun drives the water cycle. The resulting rain, rivers, ocean waves and glaciers sculpt the surface of the land. Gravitational energy provided by the Sun and Moon produces our ocean tides, and tidal energy inside the molten layers of the Earth.

The Earth’s crust is the rocky surface layer which scientists and engineers know best. Rocks are mixtures of minerals. Most rocks consist of interlocking grains or crystals cemented together naturally. Rocks vary greatly in size, shape and mineral proportions. Geologists have identified the three main rock groups as igneous, sedimentary and metamorphic.

Soil forms as weathering breaks rock into particles ranging in size from clay, silt, sand, gravel, cobbles and boulders. Air and water fill gaps between the soil particles. Chemical changes help bacteria, fungi and plants to move in. The chief influence on overburden soils is climate.

From space the presence of mankind on earth is analogous to how humans view an ant hill. Our lives and infrastructure activities are a very tiny speck in the vast spectrum of geological time and space.

We know that winds blow and oceans flow, and these are not the only parts of the Earth that are dynamic. Terra firma or solid Earth is not solid, and it is not forever fixed on the world map in space and time. Land moves about in response to natural forces. The drift of continents has a major influence on our climate and our life.

2_1.jpg

2.1 The Relative Sizes of the Sun and its Planets

2_2.jpg

2.2 The Interior Structure of the Earth

Chapter 3

GEOLOGY

Geology is the wide scope of geoscientific investigation and observation which studies the composition and arrangement of the Earth’s crust, followed by the application of these results to the art and practice of civil engineering, mining and geoenvironmental sciences.

Geologists recognize only one naturally occurring earth material called rock. Geoengineering differentiates between rocks and soils, and the reactions of rocks and soils to the forces imposed on them by earthworks and structures, and by groundwater chemistry.

The Earth has been undergoing changes for millions of years. Earthquakes, volcanic action, glaciers, floods, variable erosion and deposition, wind action and climatic factors produce the soil mantle on the Earth’s crust, which is derived from the underlying rock.

Billions of years ago when the Earth cooled from its gaseous state, it was composed of molten material. Further cooling formed a crust at the surface. Hot molten material or magma still exists at great depth below the Earth’s crust.

Continental Drift: Plate Tectonics

In 1915, Alfred Wegener, a German meteorologist and geophysicist, published The Origin of Continents and Oceans which set forth a radical hypothesis of continental drift.

Wegener suggested that a supercontinent named Pangaea, meaning all land, once existed. It was hypothesized that, about 200 million years ago, this supercontinent began breaking into smaller continents, which then drifted to their present positions.

Scientists collected substantial evidence to support the claims. The fit of South America and Africa, and the geographic distribution of fossils, rock types and structures, and ancient climates all seemed to support the idea that these current separate landmasses were once joined.

A current holistic theory to continental drift is plate tectonics. It is the framework for most geologic processes.

According to the plate tectonics model, the uppermost mantle along with the overlying crust, behaves as a strong, rigid layer, known as the lithosphere. This outermost shell overlies a weaker region in the mantle known as the asthenosphere. The lithosphere is broken into numerous segments called plates, which are in motion and are continually changing in shape and size. Seven major plates are recognized as the North American, South American, Pacific, African, Eurasian, Australian, and Antarctic plates. The largest is the Pacific plate, which is located mostly within the ocean and the continent moves with the ocean floor.

Intermediate-sized plates include the Caribbean, Nazca, Philippine, Arabian, Cocs, and Scotia plates.

The lithospheric plates move at very slow, but continuous, rates of a few centimetres a year. This movement is ultimately driven by the unequal distribution of heat within Earth. The titanic grinding movements of Earth’s lithospheric plates generate earthquakes, create volcanoes, and deform large masses of rock into mountains.

Folds and Faults

For anticline folds the beds are convex upwards, whereas, for syncline folds the beds are concave upwards.

A fault represents a surface of discontinuity along which the strata on either side have been displaced relative to each other. The displacement varies from tens of millimetres to hundreds of kilometres. The fracture may be clean break or a widely developed, infilled or mineralized fault zone.

Discontinuities

A discontinuity represents a plane of weakness within a rock mass across which the rock material is structurally discontinuous. Although discontinuities are not necessarily planes of separation, most in fact are and they possess little or no tensile strength. Discontinuities vary in size from small fissures to huge faults. The most common discontinuities are joints and bedding planes. Other important discontinuities are planes of cleavage and schistosity, fissures and faults.

According to their origin, rocks are divided into three groups.

Igneous rocks are formed from magma, which has cooled and hardened slowly.

Sedimentary rocks are formed from weathering and disintegration of igneous rocks. The further weathering of fine rock fragments into sand, silt and clay and the deposition of these soils into depressions of the Earth’s crust, followed by consolidation, cementation and pressure formed sedimentary rocks such as sandstone, limestone and shale.

Metamorphic rocks result from changes in heat or pressure, which alter other igneous or sedimentary rocks. Heat leads to recrystallization of the original rocks and pressure results in reorientation of the crystals and produces a banded or folded effect. Typical examples of metamorphism are sandstone to quartzite, limestone to marble, and shale to slate or mica.

A geologic survey of a region indicates the general type and pattern of subsurface strata to be anticipated. A geological site characterization is a preliminary step for conceptual design and construction purposes. A detailed geologic survey of a project site identifies the structural geology including the specific types of overburden soil and bedrock strata which are likely to be encountered. The geoengineering consultant may carry out a study of the regional geology and the local geology in order to plan and execute a major site exploration program. A geological site characterization is inadequate for quantitative engineering design and construction purposes.

Glacial Geology

Much of North America and Northern Eurasia are glaciated. A glacier is a large mass of ice which is formed by the accumulation and pressurized compaction of snow. Glaciers flow under the influence of gravity and/or extrusion. The effects of the glacial era are found as follows:

Glacial Advance: If the temperature trend is increasing, then the glacial winter has an advancing ice front. A

Reviews for Earth Engineering

[murraysarafinchin · Rating: 5 out of 5 stars]

Written in simple language, this reference guide provides an overview of geoengineering perspectives, principles, and practices.