The Lord Doc
Pro
So Supes could rip the helmet off unless there was a specific magic spell that made that impossible.
I mean characters from Colussus to fukking Angel have ripped that helmet off at one point or another.
No, Superman could certainly rip his helmet off, probably in a manner similar to what Hulk did in their first fight.. The question is, what would he do after that?
Traditionally, all the helmet did was protect Juggernaut from telepathic attacks; it doesn't make him any less durable.