IT IS BEST NOTE

1. CHAPTER 1 INTRODUCTION
Contents
1.1 Definition of geology and its applied branch
1.2 Scope and objectives of geology
1.3 Importance of geology in civil engineering
1.4 Earth and its interior

2. 1.1 Definition of Geology and its applied branch
Geology is the science of the Earth, including its composition & structure,
its history or its past life forms.
Generally; Geology is divided into two major groups.
1. Physical Geology
2. Historical Geology
Physical Geology deals with the materials that constitute the Earth (soils
and rocks), the structures and surface features of the Earth, and the
processes that created these structures.

3. Cont..
Historical Geology deals with the history of the Earth. Geology is further
divided into a number of branches according to the subject matter that is
covered or to the industrial or commercial applications.
Applied Branches of Geology
The applied branches of Geology use the principles of basic geology and other
sciences to understand the nature of the Earth, Earth processes, Earth
materials, and to extract the natural resources of the Earth.

4. Cont..
Some of the common applied branches of Geology are:
1. Engineering Geology: geology and engineering;
• Engineering – concerned with putting scientific knowledge to practical
use.
• Geology - concerned with the physical nature and history of the earth.
It is the application of the geologic sciences to engineering practice for
the purpose of assuring that the geologic factors affecting the location,
design, construction, operation and maintenance of engineering
structures.

5. Cont..
Provides a means to identify geologic features that could have a
consequences on the performance of engineering structures & projects.
It is also a study of how we are affected by a geological phenomenon, &
how we can affect the environment & trigger the geological process.

6. Cont..
2. Environmental Geology (science): deals with the impact of human activity on the
natural environment (Earth) and vice Versa;
3. Petrology: systematic study of rocks and their origin. It consists of Petrography &
Petrogenesis.
Petrography- (identification, description, and classification of rocks)
Petrogenesis - (study the origin of rocks);
4. Hydrology: study of underground and surface water.
5. Mineralogy: study of rock constituents or minerals;

7. Cont..
6. Geophysics: application of principles of physics to the study of the Earth. It
consists of Geomagnetics (study of Earth's Magnetic field) and Seismology (study of
earthquakes);
7. Geomorphology: study of landforms, their origin and development;
8. Stratigraphy: study of layered rocks, mostly those of sedimentary origin;
9. Geodesy: study of the form and size of the Earth;
10. Oceanography: study of oceans and basins;
11. Mining Geology: deals with the techniques of exploration and extraction of
economic minerals and rocks;

8. 1.2 Scope and Objectives of Geology
1.2.1 Scope of geology
Geology covers the whole spectrum of the Earth (oceans and
continents) from the surface (the crust) to the centre (the core).
Therefore, it is a very wide, multi-disciplinary science which necessarily
involves the basic natural science disciplines (biology, chemistry,
physics), and also geography, economics, mathematics, computer
science etc.

9. 1.2.2 Major Objectives of Geology
• Describe and interpret earth surface physical features explaining their mode of
origin;
• Clarify the history of the earth’s evolution and past lift from the records
preserved in the rocks;
• Study the Earth processes that formed it, and continuously modifying it;
• Study materials (the natural resources) which are of economic importance;
• Locate those natural resources and know their extent;

10. Cont..
• To extract the natural resources (such as oil, coal, water, economic
minerals and rocks) and use them in a sustainable manner;
• Study natural Earth hazards (e.g. earthquakes, flood, landslide,
volcanism etc) that have an influence on human welfare, and
• Study the influence of human activities on the natural earth materials
and processes in order to investigate the environmental impacts

11. 1.3 Importance of Engineering Geology in civil
Engineering
1. Provides a systematic knowledge on; Occurrence, Composition, and
Durability of construction materials.
E.g. Building stones (granite), clay & sand
2. Provide knowledge on ground water: - Quantity & Depth of
occurrence in relation to;
• Water supply,
• Irrigation,
• Excavation/Drilling works

12. Cont..
3. For evaluation of foundation problems on projects such as;
• Dams,
• Bridges
• Buildings and Other large projects
4. To understand nature and structures of rocks for determination of
stabilities, in engineering structures such as;
• Tunneling,
• Road Constructions,
• Canals (for sewerage or for pipelines)
• Cuts & Slopes

13. Main tasks of Engineering Geologists include:
• Description of the Geologic Environment pertinent to the engineering
practice;
• Description of Earth Material, their Distribution, and Generally
Physical and Chemical Characteristics;
• Deduction of the history of relevant events affecting the earth
materials
• Forecasting Future Events and Conditions that may develop for design
and construction of various Eng. Structures
• Recommendation of materials for representative sampling and testing;

14. Applications of Engineering Geology
Civil engineering:
• Buildings, industrial and offshore foundations.
• Reservoirs, fills and embankments.
• Slopes.
• Roads, airports and industrial pavements.
• Bridges.
• Retaining structures.
• Tunnels and underground space facilities.

15. Cont..
 Mining and resource development.
 Environment: waste containment systems and site remediation
 Groundwater resources development and management.

16. 1.4 Earth and its interior
The Earth is a dynamic means of a system of various subsystems or related
parts (atmosphere, hydrosphere, biosphere, and solid earth) interacting in
organized fashion. Therefore, it is constantly changing planet in terms of: -
 its internal structure (initially homogeneous, but gradually with cooling
separated into distinct concentric layers, lava spewing out of its warm
interior, ice, water and windblown sand and gravity reshaping its
surface, over and over),

17. Cont..
• its external structure (its crust shifting to build mountains).
Structure and Composition of Interior of the Earth: - The current day
Earth is not composed of a homogeneous mixture of materials rather the
materials are arranged in a series of concentric layers of differing nature.
The Earth’s interior is chemically differentiated into three major zones.

18. Cont..
As a result of the molten nature of Earth, dense materials, like
metallic iron, would have tended to sink toward the middle of the
Earth.
As cooling progressed, lighter, low-density minerals crystallized and
floated out toward the surface. The eventual result was an earth
differentiated into several major compositional zones.

19. Cont..
Figure 1.1 A schematic view of Interior of the Earth with depth to each layers from the
Earth surface

20. Cont..
Crust
It is a rigid, outer most shell of the Earth; it can be exemplified by
breadcrumbs. The crust is very thin (average 40Km).
The thinnest parts are under the oceans (oceanic crust) and go to a
depth of roughly 10 kilometers.
The thickest parts are the continents (Continental crust) which extend
down to 100 kilometers on average.

21. Cont..
Mantle
It is the next layer. It can be exemplified by sausage meat. The mantle is
the layer beneath the crust which extends about half way to the centre.
Core: is divided into two.
Outer core: This is liquid and can be exemplified by egg white. The
outer core is the layer beneath the mantle depth of 2,900-5,200
kilometers.

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Inner core: This is a solid middle bit and can be exemplified by egg yolk.
The inner core is a bit in the middle at depth of 5,200-6,373 kilometers.
It’s unattached to the mantle, suspended in the molten outer core.