Assuming datums match etc. you could import the data and create two surface models in LDD, and then use them for cut and fill calculations. You could also create contours for each set and add cut tick marks for a quick change detection.
I believe you can export the surfaces and/ or contour data...
About 10yrs ago in Wellington, New Zealand the Kiwis moved
a large 5 story hotel by using railway track and supports attached to the piers. Maybe this is helpful:
http://www.museumhotel.co.nz/history/index.html
JMTENG
Santa Rosa, CA