FCE 311 – GEOTECHNICAL ENGINEERING I
OSN - Lecture Notes
Geotechnical Engineering is the branch of civil engineering concerned with the
engineering behaviour of earth materials. It uses principles of soil mechanics, rock
mechanics and engineering geology to investigate subsurface conditions and
materials, determine the relevant physical/mechanical and chemical properties of the
materials, evaluate stability of natural slopes and man-made soil deposits, access
risks posed by site conditions, design earthworks and structure foundations and
monitor site conditions, earthwork and foundation construction.
A typical geotechnical engineering project begins with a review of project needs to
define the required material properties. Then follows a site investigation of soil,
rock, fault distribution and bedrock properties on and below an area of interest to
determine their engineering properties.
Site investigations are needed to gain an understanding of the area in or on which
the engineering will take place. Investigations can include the assessment of the risk
to humans, property and the environment from natural hazards such as earthquakes,
landslides, soil liquefaction, debris flows and rock falls.
A geotechnical engineer then determines and designs the type of foundations,
earthworks and pavement subgrades required for the intended man-made structures
to be built. Foundations are designed and constructed for structures of various sizes
such as high-rise buildings, bridges, medium to large commercial buildings, and
smaller structures where the soil conditions do not allow code-based design.
Foundations built for above-ground structures include shallow and deep foundations.
Retaining structures include earth-filled dams and retaining walls. Earthworks
include embankments, tunnels and sanitary landfills.
Geotechnical engineering is also related to coastal and ocean engineering. Coastal
engineering can involve the design and construction of wharves (structures on the
shore of harbour where ships may dock to load and unload cargo or passengers) and
jetties (structures that projects into a body of water to influence the current or tide
or to protect a harbour or shoreline from storms or erosion).
UNIVERSITY OF NAIROBI