Please look at the information and related sources for Geophysics below, or, post a
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Geophysical Publications Available for Downloading
GT-16 - Determination of Unknown Subsurface Bridge Foundations. Provides
descriptions of various geophysical implementation, equipment and exploration methods.
NAVFAC 7.01 -
Soil Mechanics. This publication includes soil/ rock identification and properties,
field exploration, field testing, instrumentation, laboratory testing, distribution of
stresses, settlement analysis, volume expansion, seepage, erosion control, drainage filters,
slope stability and slope protection.
USACE EM 1110-1-1802 - Geophysical Exploration for Engineering and Environmental
Investigations. Provides information on geophysical methodologies, seismic procedures,
electrical/ electromagnetic methods, gravity techniques, magnetic methods, subsurface
geophysical methods, remote sensing, airborne geophysical methods and engineering vibration
Geophysical Technical Guidance
Geophysical surveys are excellent for economically exploring large subsurface areas very quickly. As soil borings are
restricted to exploring a vertical line at each boring location, geophysical surveys can easily cover a large area and detect
the bedrock-soil interface and interfaces between soil layers. However, geophysical surveys can only indicate general soil
properties while soil borings provide methods for determining engineering and index properties of the soil.
Geophones - Utilizes energy sources and detectors at various locations depending on the applicability in order
to obain rock quality, cavity locations and dynamic soil properties.
Resistivity - An electrical method that uses resistivity measured in the subsoil from two electrodes of a battery
source. This method is used to estimate horizontal extents as well as vertical depths of subsurface strata. Have also been
used to locate the boundary between salt and fresh water.
Magnetic Measurements - Devices used to measure the Earth's magnetic field at closely spaced intervals
along a traverse in order to indicate the outlines of faults, bedrock, underground utilities or metallic materials.
Gravity Measurements - Measuring differences in subsurface densities as indicated by gravitational fields
and vertical intensity in order to estimate boundaries of steeply inclined subsurface irregularities such as faults or intrusions.
Some application for karst location and studies.
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