A projecting collar, usually of concrete, built around the outside of a pipe, tunnel, or conduit, or conduit under or through an Embankment Dam to lengthen the seepage path along the outer surface of the conduit.
ANTI-SEEPAGE COLLAR
Meaning of ANTI-SEEPAGE COLLAR in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012