Unseamed geotextiles depend on overlaps that grow as the subgrade softens, from about 300 mm on firm ground to a meter or more, or sewn seams, on very soft soils. GCL overlaps are typically 150 to 300 mm with added bentonite. Fill is spread in the direction of the overlaps so the top roll is pressed down instead of peeled back.
Overlap is two feet on this soft stuff, and push the stone in the direction of the laps.
Also heard as
- lap
- laps
- overlap width
Related terms
Shingle
To lay overlapping panels with the upslope piece on top, so water sheds over the lap instead of into it.
GCL
Geosynthetic clay liner: a factory-made barrier of sodium bentonite held between two geotextiles.
Separation
Keeping two different soil layers, such as an aggregate base and a soft subgrade, from mixing under load.
Biaxial geogrid
Geogrid with similar strength in both directions, used mainly to stabilize aggregate bases over soft ground.