can i retrive xml data based on uri php

lets say I have a URI which I got from $_SERVER['REQUEST_URI'] I need to make it so that the result of eg /dir1/subdir/subsubdir becomes ->dir1->subdir->subsubdir

$xml=simplexml_load_file("xml.xml") or die("Error: Cannot create object");

so I can add it to the end of $xml

any help would be appreciated