GLOSSARIES - Geotechnical Earthquake Engineering - page 516

Shotcrete Mortar or concrete pumped through a hose and projected at high velocity onto a surface.
Shotcrete can be applied by a wet or dry mix method.
Shrinkage Factor (SF) When the loose material is worked into a compacted state, the ratio of the
volume of compacted material to the volume of borrow material.
Site The particular lot or parcel of land where grading or other development is performed.
Slope An inclined ground surface. For graded slopes, the steepness is generally specified as
a ratio of horizontal:vertical (e.g., 2:1 slope). Common types of slopes include natural (unaltered)
slopes, cut slopes, false slopes (temporary slopes generated during fill compaction operations), and fill
slopes.
Slough Loose, noncompacted fill material generated during grading operations. Slough can also
refer to a shallow slope failure, such as sloughing of the slope face.
Slump In the placement of concrete, the slump is a measure of the consistency of freshly mixed con-
crete as measured by the slump test. In geotechnical engineering, a slump could also refer to a slope
failure.
Slurry Seal In the construction of asphalt pavements, a fluid mixture of bituminous emulsion, fine
aggregate, mineral filler, and water. A slurry seal is applied to the top surface of an asphalt pavement
to seal its surface and prolong its wearing life.
Soil Stabilization The treatment of soil to improve its properties. There are many methods of soil
stabilization such as adding gravel, cement, or lime to the soil. The soil could also be stabilized by
using geotextiles, by drainage, or through the use of compaction.
Specification A precise statement in the form of specific requirements. The requirements could be
applicable to a material, product, system, or engineering service.
Stabilization Fill Similar to a buttress fill, whose configuration is typically related to slope height
and is specified by the standards of practice for enhancing the stability of locally adverse conditions.
A stabilization fill is normally specified by minimum key width and depth and by maximum backcut
angle. A stabilization fill usually has a back drainage system.
Staking During grading, staking is the process where a land surveyor places wood stakes that indi-
cate the elevation of existing ground surface and the final proposed elevation per the grading plans.
Structure That which is built or constructed, an edifice or building of any kind, or any piece of
work artificially built up or composed of parts joined together in some definite manner.
Subdrain (for Canyons) A pipe and gravel or similar drainage system placed in the alignment of
canyons or former drainage channels. After placement of the subdrain, structural fill is placed on top
of the subdrain.
Subgrade For roads and airfields, the underlying soil or rock that supports the pavement section
(subbase, base, and wearing surface). The subgrade is also referred to as the basement soil or founda-
tion soil.
Substructure The foundation.
Sulfate (SO 4 ) A chemical compound occurring in some soils which, at above certain levels of con-
centration, has a corrosive effect on ordinary Portland cement concrete and some metals.
Sump A small pit excavated in the ground or through the basement floor to serve as a collection
basin for surface runoff or groundwater. A sump pump is used to periodically drain the pit when it fills
with water.
Superstructure The portion of the structure located above the foundation (includes beams,
columns, floors, and other structural and architectural members).
Tack Coat In the construction of asphalt pavements, a bituminous material that is applied to an
existing surface to provide a bond between different layers of the asphalt concrete.
Tailings In terms of grading, nonengineered fill which accumulates on or adjacent to equipment
haul roads. Tailings could also be the waste products generated during a mining operation.