Transcript cve 311 engineering geology - University of Agriculture Abeokuta

CVE 311
ENGINEERING GEOLOGY
ENGR S.O ODUNFA
DEPT. OF CIVIL ENGINEERING
UNIVERSITY OF AGRICULTURE,
ABEOKUTA
Introduction
• Engineering geology is the application of
geology in design, construction and
performance of civil engineering works
Importance of engineering geology to
in Civil engineering practices
• To recognise potential difficult ground conditions
prior to detailed design and construction
• It helps to identify areas susceptible to failure due
to geological hazards
• To establish design specifications
• To have best selection of site for engineering
purposes
• To have best selection of engineering materials
for construction
Geological Structures
• These are the modified structures formed
from primary structures due to the influence
of tectonic forces on it.
• It gives details about how inherent properties
of rocks get modified , making them either
suitable or unsuitable for civil engineering
works. Emples are: Folds,Faults,Joints and
• Uncomformities
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Not all rocks are suitable for the studies
The suitable rocks are:
Sand stones and shales – Sedimentary rock
Gneissses and schist ( to some extent) Metamorphic rock
Folds
• They bend either upwards or down wards when a set of
horizontal layers are subjected to compressive forces
• Parts of fold:
• Limbs or flanks - side of a fold
• Crest and trough – the curved portions of fold at the top
and bottom are called crest and trough respectively
• Axial plane- Imaginary plane which divides the fold intotwo
equal or nearly equal halves’
• Axis – Trace of intersection between the axialplane and the
crest or trough of the fold
• Wave length – The distance between the successive crest
or trough
Classifications and types of folds
• Based on diifferent principles the folds are
variously classified as
• Symmmetrical and asymmetrical – symmetrical
character
• Anticline and syncline – upward or downward
bend
• Occurence of plunge – plunging and non-plunging
• Uniformity of bend thickness – open and closed
• Behaviour of the fold pattern with depth – similar
and parellel
Effects of Folds and their Engineering
Importance
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Location of dams
Location of reserviours
Location of tunnels
Quarrying
Ground water occurence
Roads and railways
Faults
• These are fractures along relative i.e parallel
displacement of adjacent blocks taken place.
• Parts of fault:
• Fault plane The plane along which the
adjacent blocks relatively displaced
• Footwall and hanging wall
• Heave and thtow
• Slip
Classification and Types of Faults
• Translational and rotational faults – based on
type of displacement along fault plane
• Normal/Gravity and reverse/thrust, dextral
faults – relative movement of the footwall and
hanging wall
• Strike and dip faults – type of slip involved