Dry flood proofing with a flood wall

[mijowe]

I intend to keep flood waters out of a space (a large parking area at grade) with a flood wall. When if ever do I need to worry about the flood waters seeping below the wall and either imparting a buoyant force on the slab or simply flooding the space? Ie I don't want to spend the money on waterproofing the slab or reinforcing it for the buoyant force. Levees and sandbags hold back flood waters. I assume the time an area is flooded and the porosity of the soils are relevant and that a calculation can be done. Does FEMA or another source define this risk?

 

[oldestguy]

What you will have meets the general requirements of a levee. Perhaps this publication will assist.

http://www.publications.usace.army.mil/Portals/76/Publications/EngineerManuals/EM_1110-2-1913.pdf

 

[cvg]

the water will seep below the wall. a transient seepage analysis based on the depth and duration of the flood loading will give you an idea of how long it will take. This is a task for a qualified, experienced geotechnical engineer. I would not suggest that a structural engineer attempt this without prior experience.

In addition to oldest guys recommendation, suggest the following:
EM 1110-2-2502 Retaining and Flood Walls
EM 1110-2-1901 Seepage Analysis and Control for Dams

 

[mijowe]

Thanks, this is the kind of reading i was looking for.

 

[oldestguy]

OG once more. The seepage that may occur may or may not be critical. But for your question " When if ever do I need to worry about the flood waters seeping below the wall ", a short comment. Critical is the head loss of the seepage water as it emerges. When the loss of head approaches 1 foot in one foot of flow, you have quick sand. Along with that can be major failure of the wall.