rock pile
/ˈrɒk pʌɪl/noun
A heap of stones; frequently with allusion to the convict's task of breaking stones. Hence (US slang ): a jail or prison; ( humorously ) any place in which hard work is supposedly performed. Also ( rarely ): a large or imposing building.
Origin
Mid 19th century; earliest use found in Robert Montgomery (1807–1855), poet and Church of England clergyman. From rock + pile.