Undercut, Shallow Undercut, and Aggregate Subbase (Subgrade Stabilization)

Subgrade Stabilization
      Subgrade stabilization is mostly called for by the Geotechnical Unit and on rare occasions may be called for by Pavement Management. It is done to stabilize the subgrade when required. For earthwork to work properly, the undercut component must tie to the subgrade line. In most cases, the quantities for Undercut Excavation and Subgrade Stabilization Material must be calculated. There are three conditions in which undercut is used and further explanation of the derived quantities is needed.

Proposed Undercut (Subgrade Stabilization) below Existing Ground. Note all undercut excavation is considered.

Proposed Undercut (Subgrade Stabilization) Partially Above and Below Existing Ground. Note only partial undercut excavation is considered.

Proposed Undercut (Subgrade Stabilization) In Fills. Note, there is no undercut excavation in this case.

Earthwork Computation

SHALLOW UNDERCUT

(Suitable) Subgrade Excavation - The amount of shallow undercut excavated (shown in red shapes as excavation only).
(Class IV) Fill - The amount of Class IV material to be backfilled (shown in red shapes).

UNDERCUT (REGULAR)

(Suitable) Subgrade Excavation - The amount of undercut excavated (shown in blue shapes as excavation only).
(Suitable) Fill - Include earth material to be backfilled of undercut (shown in blue shapes).

SUBGRADE STABILIZATION IN FILLS

(Suitable) Fill - Amount of earth material required for roadway embankment(shown in blue shapes).
(Class IV) Fill - Amount of subgrade stabilization material in fills (shown in red shapes).