Soldier Piles Anchorage

[jas4]

Can soldier piles that are socketed 5 feet into bedrock
(HP 10 in 18 in. dia. sockets ) be backfilled with
granular fill in the socket or do they have to be concrete
filled? If so ,how to determine the base capacity?

 

[GeoPaveTraffic]

Like much in life, it depends. If you could provide some information on the use of the soldier piles, the loads involved and any tie backs, then we may be able to give you some feedback.

 

[jas4]

Additional Information:
The soldier piles are 8' o.c. retaining a 12' high level
granular backfill (no surcharge). The lagging is concrete planks with free draining capabilities. The soldier piles will have tie-backs at 1.5' below grade on each pile. The
piles will be about 5 feet into soil then 5 feet into bedrock.

 

[PEinc]

jas4,

Sounds like overkill to me. Most walls 12 feet high do not need tiebacks. Most relatively low tiedback walls do not need 10 feet of embedment - especially with 5 feet of it in rock. Do you have any high surcharge loads behind the wall? Do you have very bad soils?

 

[PEinc]

P.S.
Is this a cut situation or a fill situation? Are you constructing the wall from the top down? Are you installing the lagging in lifts working downward or are you open cutting 12 feet deep and then stacking the precast lagging from the bottom up?

Precast lagging is not recommended for cut situations because it is too hard to work with and to hold in place when lower cuts of excavation are made. Precast lagging usually needs to be installed by stacking and backfilling it starting at subgrade and then working upward. Steeply sloped open cuts can make an unsafe or unstable situation for taller walls.

Also, are you going to stress the tieback anchors? If so, you will probably damage the precast panels when you jack the tiebacks.

I would not backfill the drill holes with stone. I'd use lean mix concrete or flowable fill.

Tiedback walls with precast lagging were not a good idea in the 1980's and are an even worse idea today.