When a subgrade will not carry equipment or fails a proof roll, the usual fix is to undercut a set depth and backfill with stone or select fill. Geosynthetics are often used to cut the undercut depth or avoid it, by laying a woven or grid on the soft soil and building the platform over it. Undercut quantities are a frequent change-order fight, so they are measured and logged.
Engineer wants three feet of undercut, but with grid and fabric we can bridge it with eighteen inches of rock.
Also heard as
- undercut and replace
- over-excavation
- muck out
Related terms
Subgrade
Native or prepared soil surface on which a pavement, aggregate base or liner system is built.
Stabilization
Improving how soft ground or an aggregate base carries traffic by adding geogrids or geotextiles.
Mud wave
Bulge of very soft soil shoved up ahead of fill being placed on weak ground.
Separation
Keeping two different soil layers, such as an aggregate base and a soft subgrade, from mixing under load.
Same word, different worlds
A recess deliberately machined below finished size so the coating can fill it to full thickness.
Welding, Brazing & NDEA notch the arc melts into the base metal beside the weld toe that the weld metal never fills back in.
Gear EngineeringA notch cut into the base of small-pinion teeth when the generating tool removes part of the working involute.