1 overview

FCE 311 GEOTECHNICAL ENGINEERING

COURSE OUTLINE AND

GENERAL OVERVIEW

Department of Civil & Construction Engineering

University of Nairobi

Course Description

 • This course is an introductory part of Soil

Mechanics, which focuses on soil formation, soil structures, physical properties of soils, soil classifications, soil compaction and permeability.

Student Learning Outcomes

• Competence in the principles of soil mechanics

• Ability to list the relevant engineering properties of soils and their characteristics and describe the factors which control these properties.

•  Apply laboratory methods of determining the properties of soils.

Student Learning Outcomes

• Ability to identify common situations when the soil becomes a factor in an engineering or environmental problem.

• Ability to apply basic analytical procedures to obtain the engineering quantity desired and understand their limitations.

Teaching Methodology and Techniques

• This course relies on lectures and Power Point presentation by the lecturer. Worked examples will be offered. Students will then be required to contribute to discussions based on the explanations and will need to read the corresponding section in the assigned textbook.

Detailed Course outline:

Lesson 1:• Introduction - definitions of Soil Mechanics

and Soil.

• Soil formation - physical and chemical weathering, residual and alluvial soils, and tropical soils.

Detailed Course outline:

Lesson 2:• Clay mineralogy, soil structure, Lesson 3:• Basic properties, Phase relationshipsLesson 4:Physical properties of soils, water content,

specific gravity, bulk and dry densities, field densities.

Detailed Course outline:Lesson 5:• Consistency and plasticity of soils.Lesson 6:• Determination of soil properties by laboratory

testingLesson 7:• Particle size analysis and Lesson 8:Soil description and Classification

Detailed Course outline:Lesson 9:• Soil compaction, laboratory and field

compaction tests. Dry density/water content/air content relationships.

Laboratory tests

• Liquid Limit determination• Plastic Limit determination• Dry Density Determination using Sand

Replacement• Particle Size Distribution Determination by

Dry Sieving• Compaction Tests• Specific Gravity of Soils

Assessment

• Lectures – Mandatory • Laboratory tests – 10%• CAT – 20%• Final Examination – 70%

General Overview

ground

Typical Geotechnical Project

construction site

Geo-Laboratory~ for testing

Design Office~ for design & analysis

soil samples

soil properties

design details

01/05/23

GEOTECHNICAL APPLICATIONS

Shallow Foundations

15bed rock

firm ground

~ for transferring building loads to underlying ground

~ mostly for firm soils or light loads

Shallow Foundations

Deep Foundations

17

bed rock

weak soil

PILE

~ for transferring building loads to underlying ground

~ mostly for weak soils or heavy loads

Deep Foundations

18Driven timber piles

Retaining Walls

19

~ for retaining soils from spreading laterally

RoadTrain

retaining wall

Earth Dams

20

~ for impounding water

soil

reservoirclay core shell

Concrete Dams

21

reservoir

soil

concrete dam

Concrete Dams

22Three Gorges Dam, Hong Kong

Concrete Dams

23

Earthworks

24Roadwork

~ preparing the ground prior to construction

Geofabrics

25

~ used for reinforcement, separation, filtration and drainage in roads, retaining walls, embankments…

Geofabrics used Isiolo Airport

Reinforced Earth Walls

26

~ using geofabrics to strengthen the soil

Soil Nailing

27

~ steel rods placed into holes drilled into the walls and grouted

Sheet Piles

28

~ sheets of interlockingsteel or timber driven into the ground, forming a continuous sheet

ship

warehouse

sheet pile

Sheet Piles

29

~ resist lateral earth pressures

~ used in excavations, waterfront structures, ..

Sheet Piles

30

~ used in temporary works

Cofferdam

31

~ sheet pile walls enclosing an area, to prevent water seeping in

Landslides

32

Tunneling

33

Blasting

34

For ore recovery in mines

Ground Improvement

35Impact Roller to Compact the Ground

Ground Improvement

36Sheepsfoot Roller to Compact Clay Soils

Ground Improvement

37Smooth-wheeled Roller

Ground Improvement

38

Big weights dropped from 25 m, compacting the ground.

Craters formed in compaction

Environmental Geomechanics

39

Waste Disposal in Landfills

Instrumentation

40

~ to monitor the performances of earth and earth supported structures

~ to measure loads, pressures, deformations, strains,…

Soil Testing

Cone Penetration Test Truck

Soil Testing

More Field Tests

Standard Penetration TestVane Shear Test

Soil Testing

43Triaxial Test on Soil Sample in Laboratory

Soil Testing

44Variety of Field Testing Devices

Typical Safety Factors

45

Type of Design Safety Factor

Probability of Failure

Earthworks 1.3-1.5 1/500

Retaining structures

1.5-2.0 1/1500

Foundations 2.0-3.0 1/5000

Great Contributors to the Developments in Geotechnical

Engineering

Karl Terzaghi1883-1963

C.A.Coulomb1736-1806

WJM Rankine1820-1872 A.Casagrande

1902-1981

L. Bjerrum1918-1973

A.W.Skempton1914-

G.F.Sowers1921-1996

G.A. Leonards1921-1997

Geotechnical Engineering Landmarks

Leaning Tower of Pisa

49

Our blunders become monuments!

Hoover Dam, USA

50Tallest (221 m) concrete dam

Petronas Tower, Malaysia

51

Tallest building in the world

Monuments

52

and….

Geo-engineering at UoN

54

FCE 311Geotechnical Engineering I

FCE 411Geotechnical Engineering II

FCE 511Geotechnical Engineering III

PostGraduateGeotechnical Engineering

Practicals

55

~ five practical sessions~ closed footwear must be worn in the lab

Some Suggestions

56

Attend the lectures.

Develop a good feel for the subject.

It takes longer to understand from the lecture notes

It is practical, interesting and makes lot of sense.