[suhb-greyd]Civil Engineering, Building Trades.
- the prepared earth surface on which a pavement or the ballast of a railroad track is placed or upon which the foundation of a structure is built.
- beneath the finished ground level of a project.
Origin of subgrade
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for subgrade
The side-walls and subgrade electric conduits were water-proofed with felt and pitch.
In the subgrade telephone and telegraph ducts east of the Manhattan Shaft, much trouble was caused by grout in the ducts.
When the work was finished, a subgrade reversed-grade drain carried the water to the shaft sump by gravity.
Some engineers advocate that in preparing the subgrade, the earth be thoroughly rolled; others prefer not to roll the subgrade.American Rural Highways
T. R. Agg
The pavement laid was bitulithic and the subgrade was an old macadam road built by the County.Third Biennial Report of the Oregon State Highway Commission
S. Benson, W. L. Thompson, R. A. Booth, Herbert Nunn
- the ground beneath a roadway or pavement
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012