GEOLOGY FOR CIVIL ENGINEERS
SITE
INVESTIGATIONS
WHAT IS
A SITE
INVESTIGATION?
A site investigation simply is
the process of the collection
of information, the appraisal of
data, assessment, and
reporting without which the
hazards in the ground beneath
the site cannot be known.
-British Archaeoligical Jobs
and Resources.
-RSA GEOTECHNICS LTD
Site investigation is carried out in
order to enable a geotechnical and
geoenvironmental assessment of
the ground conditions and analysis
of the engineering and
environmental considerations
related to the proposed
development.
SITE
CLASSIFICATION
A site classification, also known as a soil or
lot classification is a series of tests conducted
on a site to classify the soil conditions,
enabling the engineer to design the building
foundations.
The purpose of a site classification is to
determine the expected level of reactive soil
movement on your site.
SITE CLASSIFICATIONS
INCLUDE:
BOREHOLE DRILLING
SITE CLASSIFICATIONS
INCLUDE:
DENSITY SOIL PROFILES
(DCP’S OR PP’S)
SITE CLASSIFICATIONS
INCLUDE:
ABOVE SURFACE FEATURES
AND OBSERVATIONS
SITE CLASSIFICATIONS
INCLUDE:
SOIL CLASSIFICATION
SITE CLASSIFICATIONS
INCLUDE:
WIND CLASSIFICATION
The information is essential for
the design of structures & for
planning construction
techniques.
INTENSITY OF SITE
INVESTIGATION
Site investigation is done for
obtaining the information about
surface & subsurface conditions
at the site of proposed
construction.
Site investigations are generally done to obtain
the information useful for following purposes.
To select the type and depth of foundation for
given structure.
To determine the bearing capacity of soil.
To estimate the probable maximum &
differential settlement.
To establish the ground water level & to
determine the properties of water.
To predict the lateral earth pressure against
retaining walls & abutments.
To select suitable construction techniques.
To predict & to solve potential foundation
problems.
To ascertain the suitability of the soil as a construction
material.
To investigate the safety of the existing structures & to
suggest the remedial measures.
GEOLOGIC
RECONNAISSANCE
The results of the geologic reconnaissance
are used to assess the need for more
detailed
investigation
and
whether
additional technical expertise is needed.
Geologic reconnaissance includes the collection
and review of existing data.
Site should be assessed in terms of the following:
Characteristics
Geomorphology
Topography
Drainage
Other conditions
All of these might affect the suitability of the site for its
intended use and for potential impacts on natural
resources.
SITE VISITS
MAY BE
CONDUCTED
TO:
Assess the suitability of the area for
the proposed project
·
Verify the accuracy or adequacy of
existing information
Identify significant gaps in
information needed to continue with
the design.
EVALUATE
The engineering properties of
soil and rock materials need to
be evaluated.
ADDRESS
Consideration
of
how
the
operation of the proposed project,
structure, or practice might affect
local natural resources must be
addressed.
ADDRESS
Logistical concerns, such as
access, that may affect future
activities also need to be
addressed.
REVIEW
Existing data and information
should be reviewed before
field investigation.
DATA AND INFORMATION
SOURCES INCLUDE:
GEOLOGIC MAPS
DATA AND INFORMATION
SOURCES INCLUDE:
TOPOGRAPHIC MAPS
DATA AND INFORMATION
SOURCES INCLUDE:
WELL LOGS
DATA AND INFORMATION
SOURCES INCLUDE:
AERIAL PHOTOGRAPHS
DATA AND INFORMATION
SOURCES INCLUDE:
OTHER IMAGERY
DATA AND INFORMATION
SOURCES INCLUDE:
SOIL SURVEYS
DATA AND INFORMATION
SOURCES INCLUDE:
WATER AND MINERAL RESOURCE
REPORTS
DATA AND INFORMATION
SOURCES INCLUDE:
OTHER INFORMATION SOURCES THAT
PERTAIN TO THE AREA AND THE
NATURE OF THE PROJECT
To recognize hazards
To verify the accuracy or adequacy
of existing information
To identify significant gaps in information
needed to continue with design.
LIMITED ON-SITE INVESTIGATIONS
MAY BE CONDUCTED TO ASSESS
THE FEASIBILITY AND SUITABILITY
OF THE SITE:
general geology of the site:
surface and subsurface
earth materials.
geologic conditions that
may affect erosion and
sedimentation
Data gathered during
the reconnaissance
are primarily
descriptive and
should include the
following:
geologic conditions that
may influence groundwater
movement and recharge
general character of
topography and stream
system
engineering properties of
soil and rock materials
presence and activity of
faults
general relationship
between the geologic
conditions at the site and
known or typical design
requirements for the
proposed conservation
practice or structure
known or projected mining
activities and oil or gas
extraction
PRELIMINARY
SITE
INVESTIGATION
This phase includes gathering information such as the type of
structure to be constructed and its future use, the requirements
of local building codes, and the column and load bearing wall
loads.
Considerable savings in the exploration program can
sometimes be realized if the geotechnical engineer in
charge of the project thoroughly reviews the existing
information regarding the subsoil conditions at the
site under consideration.
Useful information can be obtained from the following
sources.
Geologic survey maps.
County soil survey maps
Soil manuals published by the state highway
department.
Existing soil exploration reports prepared
for the construction of nearby structures.
The engineer should visually inspect the
site and the surrounding area.
REFERENCES:
https://civiltoday.com/geotechnical-engineering/siteinvestigation/19-site-investigation
https://directives.sc.egov.usda.gov/OpenNonWebContent.a
spx?content=31846.wba
https://www.nastasiassociates.com.au/geotechnical_investi
gations.html
Ella Faye B.
Atienza
Damme Levi I.
Fabian
Warren Mae P.
Paciones
SITE INVESTIGATIONS