Allusion
An allusion is a reference to a famous historical, literary, cultural, religious or mythological event or person. In this case the allusion is the Greek Mythological hero, Hercules. I'm not sure the comparison fits. Joe's much more mild mannered than Hercules was. I also don't see the flaws in Joe that I see in Hercules. I'll give Mr. Dickens the benefit of the doubt on this one and keep searching.