CE 140 Soil Mechanics
Geotechnical Data Report
A geotechnical investigation is necessary for most civil engineering works.
depth of the investigation is a function of the risk of the work, the loads to be imposed on
the soil, the history of the site, and the economy of the project.
investigations have four major components: literature review, field testing, laboratory
testing, and result interpretation/recommendation.
The literature review examines existing information available relevant to the site.
Though a literature review can provide useful information related to the site conditions, it
is not a sufficient replacement for a thorough site-specific testing program.
can include historical documents relating to use of the site, agricultural reports, aerial
photographs, previous geotechnical studies (both onsite and for nearby sites), and
geologic maps from the USGS.
Historical documentation of the site usage can be difficult to obtain, but can
uncover important information that could affect the quality of the site for the current
Often in urban settings, sites can contain debris from old structures, garbage
(remember there wasn’t any sanitation engineering!), barrels of chemical waste (oil,
sludge waste, etc) and contaminated soils.
Discovery of such conditions can require
much more effort and money for the geotechnical investigation.
Garbage and debris may
need to be removed and replaced; contaminated soils must be cleaned up or removed.
Any contamination of the site often then requires involvement of the local and/or federal
Environmental Protection Agencies.
Permits for removal and disposal can delay projects
for months or even years.
Agricultural reports can be useful to determine some soil properties, but often only
soils usefulness as an agricultural
information can be useful to determine hydrologic properties of the soil, depth of soil
and, to a limited extent, the type of soil encountered.
Aerial photographs are helpful to view geologic properties of the site.
emphasize large-scale geologic characteristics that cannot be easily identified with a site
Historic landslides, faults, drainage paths and vegetation changes (relates to
hydrologic properties of the soil) can be spotted on aerial photographs.
characteristics may affect decisions regarding the usefulness of the site, necessary
stabilization methods and necessary drainage structures.