Blue Marl

[rcjordan]

I've mentioned it in construction threads in the past.  Here's a good vid.  Also, the top comments are why I like /r ... I "Am geotechnical engineer"

Clean excavator dig : oddlysatisfying

https://old.reddit.com/r/oddlysatisfying/comments/17qz4t1/clean_excavator_dig/

[Rupert]

"clay" in the UK is used to line canals.

We have "boulder clay" under our house, yes the surface dries, and cracks but it is very stable. I guess if there were extremes of wet/dry it might be a problem?

[rcjordan]

I once read that North Carolina has the largest number of different types of clays --the inland topsoils are almost universally orange-to-red.  Along the coast, we have sandy topsoil and bands of reddish clay below. The red clays are hard when dry (but will expand some when soaked). But occasionally you'll hit a band of what local contractors call 'blue marl.'  It is absolutely the stickiest, gooey-est, awful-est stuff to encounter where you need to dig. It will literally pull a shovel out of your hand.  It will ooze out from heavy structures, that's why the engineers and construction guys go on & on about it in the comments.

>canal

Ha! I hadn't heard of that.  I'd hate to have the job of applying it.