Tolkien always denied that LotR was a specific allegory for WW2 or anything else.

"Tolkien, however, repeatedly insisted that his works were not an allegory of any kind. He states in the foreword to The Lord of the Rings that he disliked allegories and that the story was not one."

Source: [link to en.wikipedia.org]

However, he also stated that "An author cannot of course remain wholly unaffected by his experience", and he was a veteran of WW1. Certainly this informed his depiction of war.