Topic 1

TOPIC 1
INTRODUCTION TO GEOTECHNIC

TOPIC 1 INTRODUCTION TO GEOTECHNIC

Upon completion this chapter,
students should be able to:

PLO 1 – Apply knowledge of applied
mathematics, applied science,
engineering fundamental and an
engineering specialization as
specified in DK1 to DK4 respectively
to wide practical procedures and
practices.

Prepared by Julia MU

TOPIC 1 INTRODUCTION TO GEOTECHNIC What is soil?
- Soil is a natural body consisting of layers (soil horizons)
Mechanics of Soil:
- Soil mechanics is a field of the civil engineering of primarily mineral constituents, which differ from their
parent materials in their texture, structure, consistency,
discipline that studies the mechanical behavior of soil. color, chemical, biological and other physical
characteristics.
Geotechnical engineering: - Soil is composed of particles of broken rock that have
- Geotechnical engineering uses principles of soil been altered by chemical and mechanical processes
that include weathering, erosion and precipitation
mechanics and rock mechanics.
- It include to investigate subsurface conditions and Types of rock

materials; determine the relevant Igneous
physical/mechanical and chemical properties of Rock
these materials; evaluate stability of natural slopes
and man-made soil deposits; assess risks posed by Sedimentary
site conditions; design earthworks and structure Rock
foundations; and monitor site conditions, earthwork
and foundation construction. Metamorphic
Rock

Prepared by Julia MU

TOPIC 1 INTRODUCTION TO GEOTECHNIC

Igneous Rock

- Formed from 2 methods: Example:
cooling or Granite
hardened a) Intrusive Basalt
process of –plutonic Gabbro
magma or lava Obsidian
b) Extrusive Rhyolite
- May form – volcanic Andesite
with or Diorite
without Pumice
crystallization

Prepared by Julia MU

TOPIC 1 INTRODUCTION TO GEOTECHNIC

Prepared by Julia MU

TOPIC 1 INTRODUCTION TO GEOTECHNIC

Sedimentary Rock

Formed from Remains of Example:
cementing, living things Conglomerate
compacting and on the sea
hardening floor or on Sandstone
Mudstone
process. land. Limestone
Diatomite
It also deposited Layered
at the earth’s appearance Shale
surface and and presence

within bodies of of fossils
water.

Take thousands
of years to form.

Prepared by Julia MU

TOPIC 1 INTRODUCTION TO GEOTECHNIC

Prepared by Julia MU

TOPIC 1 INTRODUCTION TO GEOTECHNIC

Metamorphic Rock

Form from Transformed Example:
heat and along with the Marble
pressure Slate
applied to structure. Gneiss
igneous or Pegmatite
sedimentary Granite → Phyllite
rocks. It gneiss Quartzite
change into a
new type of Shale → slate
→ schist
rock.
Limestone →
marble

Prepared by Julia MU

TOPIC 1 INTRODUCTION TO GEOTECHNIC

Prepared by Julia MU

TOPIC 1 INTRODUCTION TO GEOTECHNIC Video of rock formation
Youtube link: shorturl.at/tSXZ7
Rock Cycle

Prepared by Julia MU

TOPIC 1 INTRODUCTION TO GEOTECHNIC Organic soil
- The upper layer of soil.
Soil formation: - Usually the top 2 inches to 8 inches.
- Soil formation occurs as a result of - Organic soil is a material not suitable for

a gradual breakdown of rock. engineering because of its high
- Rocks are broken into finer compressibility and low shear strength.

particles through many process
caused by weathering and erosion
(disintegration and decomposition)

Soil Classification:
1. Organic soil
2. Residual soil
3. Transported soil

Prepared by Julia MU

TOPIC 1 INTRODUCTION TO GEOTECHNIC

Residual Soil:
- Formed by weathering of rocks but

located at the place of origin
- Varieties of thickness
- Divided into three zone:
a) Upper zone – high degree of

weathering
b) Intermediate zone – weathering at

the top part and deposition at bottom
c) Partially weathered zone – transition

from weathered material to the
unweather

Prepared by Julia MU

TOPIC 1 INTRODUCTION TO GEOTECHNIC Transported Soil:
- Soil that have been moved from their

place origin by transported agent to a
new place by one or more erosion
agents.
- Transporting agent:
a) glacier
b) water
c) wind
d) Gravity
- The soil will have a mineral composition
different from that of the bedrock

Prepared by Julia MU