Yeah you are right Ward, it’s a very interesting topic to get into. Geology was my subject but I'm not an engineer. For the earthworks to be done, you”ll definitely need the help of a geotechnical engineer. They use many techniques to determine the soil and rock behaviour. Sorry I don’t have a deep knowledge in this but I guess some geotechnical contractors such as DST people (
https://www.dstgroup.com/services/geotechnical-engineering/ground-investigation-in-situ-testing/ ) can help you.
