FS in TEmporary Excavations 5

[pelelo]

ANyone knows if there is any excavation manual that specifies the minimum FS that needs to be met for temporary excavations?

Please advise. Thanks

 

[oldestguy]

You won't find it. Why would anyone publish instructions or guides for "temporary excavations"? That's generally the time for a cave in, when first being dug.

 

[MTNClimber]

If my memory serves me right, Duncan and Wright's Soil Strength and Slope Stability has some guidance.

 

[cvg]

caltrans trenching and shoring manual

https://dot.ca.gov/-/media/dot-medi...struction/201906-sc-trenchingshoring-a11y.pdf

 

[Guest090822]

A few state DOT's in the Northeast generally allow a 25% reduction to the factor of safety for temporary conditions, but it depends on what you are doing. Is this for a sheeting design, open trench, etc.?

 

[pelelo]

Thanks engineers.

this is for a 10 ft excavation (open trench), 8 ft wide.

 

[oldestguy]

not knowing soil type, etc., I'd say, very questionable.

 

[r13]

If this is a temporary excavation, I suggest to use/rent a metal trench box instead of sheeting. Local shoring company maybe able to come up something for you.

 

[HENRYZAU]

For global slope stability, a minimum FS of 1.2 may be adopted if there is no sensitive structure/utility nearby. If there is, ground movement/impact on adjacent structure/utility is likely the governing factors, FS may be 1.5 or higher.