what sealant for this application? PHOTO

[mele63]

Some master craftsman used a dull axe to cut this hole. I want to seal it to keep mud and stones out of the sump pit. Should I pump a tube (or two) of silicone caulk in there? What about foam insulation; that expands real nice but I'm not sure how it holds up around water. Thanks.

[HayZee518]

cut a piece of screening to fit around the pipe as a sump hole is supposed to receive ground water to be pumped out.