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In transport engineering, subgrade is the native material underneath a constructed
In transport engineering, subgrade is the native material underneath a constructed road
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation.
There are many types o ...
,http://www.highwaysmaintenance.com/drainage.htm The Idiots' Guide to Highways Maintenance ''highwaysmaintenence.com'' pavement or railway track
A railway track (British English and UIC terminology) or railroad track (American English), also known as permanent way or simply track, is the structure on a railway or railroad consisting of the rails, fasteners, railroad ties (sleeper ...
(US: railroad track). It is also called formation level.
The term can also refer to imported material that has been used to build an embankment
Embankment may refer to:
Geology and geography
* A levee, an artificial bank raised above the immediately surrounding land to redirect or prevent flooding by a river, lake or sea
* Embankment (earthworks), a raised bank to carry a road, railway ...
.
Construction
Subgrades are commonly compacted before the construction of a road, pavement or railway trackSee also
*Subsoil
Subsoil is the layer of soil under the topsoil on the surface of the ground. Like topsoil, it is composed of a variable mixture of small particles such as sand, silt and clay, but with a much lower percentage of organic matter and humus, and ...
* Track bed
References
{{Geotechnical engineering Road transport Pavements Transportation engineering Permanent way