Chapter 2 Flashcards
Excavation
removes weak or unstable soil until a solid bearing stratum is reached.
Backfill
is where soil is put back once the excavation is complete
Types of Excavations
shallow and deep
Shallow Excavation
take place close to grade, if not on grade
Sloped Excavation
less expensive than sheeted excavations, but it requires a site without nearby property line, adjacent structures or limits on excavation.
Benched Excavations
excavations are deep excavations that allow for a sloping of grade
Sheet/Support excavations
useful when there is a site restriction, the foundation is too close to the property line and when there is poor soil cohesion.
Types of support excavations
cantilevered or braced
Types of braced excavation
Crosslot, Rakers, Tiebacks
Crosslot
- where temporary steel columns are driven into the earth to support where the foundation will be placed
Rakers
When the excavation is too wide for crosslot bracing, they are used to support the soil
Tiebacks
used instead of braces to support the sheeting while having a open excavation where steel cables are used and anchored into the ground for support.
Solider Beams
where helical piles are driven into the earth lagging is used to retain the soil outside of the excavation
Sheeting
consists of vertical planks of wood, steel that are placed tightly against each other
Shotcrete
when excavation happens first the sloped sides are reinforced with concrete to temporarily hold a steep slope
