Water pressure on sheet piles

[Lovi]

Hey all, Im designing a cofferdam for the construction of a pad 3.5m x 3.5 m pad foundation, therefore a short term structure. Cofferdam is to be circular. The ground is a fully saturated sitly clay, fairly dense. there is a river about 300m away.

In determining water pressures, my guess is that there will be no significant seepage of water into the excavation during the construction since it is only short term and the permeability is very low.

does this seem a reasonable judgement?

 

[fattdad]

No, it's not reasonable. Irrespective of short-term conditions, the pore pressure at the base of the excavation will be high. The relief of this pore pressure will lead to instability. You need to consider the flow net conditions to minimize critical gradients at the base (and minimize base heave). This is one element of stable cofferdam design that needs to be considered. Earth pressures being another element of design.

Interesting project!

f-d

¡papá gordo ain’t no madre flaca!