is there any way to bulk load dita documents to windchill as dynamic documents using the load from file frame work of windchill

If these are XML documents that require bursting, then it's not possible. The only way to burst documents into Windchill is through Arbortext. Our company has written a utility that can automate bursting using Arbortext Publishing Engine for bulk migrations. This is the only way that I'm aware to do bulk bursting.

If these are not bursted documents, you may be able to use Info Engine as a bulk loader, too.