Would you notice a curve. Most brick today is a little short of 8" (.166"scale) X a little short of 2 2/3" (.0556"scale) I'm thinking to do this you would probably want to simulate bricks at least twice that size which would still be interesting.
Anywho. This is how the pit looked NS Conway yard, Beaver County Pennsylvania.
The pit is used as a collection basin for all water and other fluids from the engine facility. Collected waste water then is treated at an on site plant to remove all that wonderful stuff you see.
We, Anthony, (Lurker 2004), and I got a really good tour that day. We were asked if we wanted to go down in the pit, but declined.
We eventually did a gravel/fine ballast base in both model TT I am responsible for.
Modular TT
Layout TT
Best wishes on your project.
Mike