Levee Underseepage
Levee Underseepage
(OP)
Assuming a clay levee over an impervious top stratum overlying sand and fully loaded; is there a difference between the factor of safety against piping (FS=ic/i) at the levee toe (landside)
versus the factor of safety against uplift (landside toe)? Are these terms essentially the same phenomenon?
versus the factor of safety against uplift (landside toe)? Are these terms essentially the same phenomenon?
RE: Levee Underseepage
In short, the factors of safety can be different since they represent different phenomenon. However, criteria are also usually quite different.
Personally, I use the method described in EM 1110-1-1913 by USACE for the design of levees. In that method the gradiant accross the impervious statum is compared to 0.5 for materials with a moist unit weight above 110 pcf.
Mike Lambert
RE: Levee Underseepage
The safety factor against uplift is more applicable for your case. The confining layer(impervious stratum) may experience blowout if the seepage pressure in the pervious layer is higher than the overburden pressure of the confining layer .
RE: Levee Underseepage