Underpinning is the securing, stabilizing, or supporting of an existing foundation.
Several procedures are available, including pressure or compaction grouting,
micropiles, or soil solidification. Underpinning can be temporary, as in the case where excavation is needed close by or abutting an existing foundation that will destabilize the existing foundation. Underpinning can also be permanent, for shoring up an existing foundation where environmental or planned conditions have changed rendering the existing soil bearing capacity inadequate.
