Carolina Sunrock constructed a new primary crusher and needed a 51 foot tall retaining wall to create the grade separation. They went with a Redi-Rock faced wall, and were in the unique position to buy the forms and cast the blocks themselves since they operate a redi-mix plant. The reinforced zone extends 57 feet behind the wall because of the heavy surcharge loads from the haul trucks. Read more about the case study at the link below.
[Update Jan 28, 2008] It appears as if the Port of Seattle is in some hot water for some alleged shady dealings with one of the contractors on the project. More at Seattle Times. [/Update]
Erosion Control magazine has an interesting article on MSE Walls. I think the tie-in of MSE Walls with erosion control is a little questionable (they did mention wall drainage a few times), but the article highlights several interesting projects, particularly the Seattle-Tacoma Airport or Sea-Tac Third Runway Project retaining walls. The West wall for that project is the tallest MSE Wall in North America, 130-ft at its highest point. More after the break. (Photo by Sea-Tac Airport)