Posted by Rob on April 24, 2005
In Reply to: Herculaneum effort posted by Lynn Myrick on April 24, 2005
I'd never heard the expression before. I would imagine that it was originally a malapropism. Google finds 50 references to this phrase, but more than 45,000 to "Herculean Effort".
On the other hand, I could imagine appropriate uses of it, signifying an heroic effort that ultimately fails (and leaves you buried under tons of slag).
The expression seems to have been used by Lucy Maud Montgomery in Anne of Avonlea (see here). There's also an interesting item on an Art-Crit site (see here)