No, that's from digging pipeline trenches offshore Gulf of Mexico's sandy side clays. You might have a look at the Corps of Engineers coastal engineering and protection design manuals available online.
BigInch, thanks again. Those USACE manuals are quite intense but I am sure they are good reference. Hope I can find something about Slope Stability for Dredging. Thanks !
Sounds like you should do some intense reading. I'm sure you'll find what you need there. They contain very practical design methods and are well worth the read.
Technology is stealing American jobs. Stop visas for robots.