CVE 311 ENGINEERING GEOLOGY

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CVE 311ENGINEERING GEOLOGY

• ENGR S.O ODUNFA
• DEPT. OF CIVIL ENGINEERING
• UNIVERSITY OF AGRICULTURE, ABEOKUTA

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Introduction

• Engineering geology is the application of geology
  in design, construction and performance of civil
  engineering works

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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

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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

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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

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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

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Effects of Folds and their Engineering Importance

• Location of dams
• Location of reserviours
• Location of tunnels
• Quarrying
• Ground water occurence
• Roads and railways

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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

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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