I never worked with precast, but I wouldn’t think it would take too long.
Once the ground is prepped and the foundation done I imagine the precast sheets would go up pretty quickly.
The hardest part would be tying them together as they are set.
A good crane crew could set them in place quickly.
Getting them tied together would take a little longer.
IMO you would have to first build a good road to truck the precast in on.
Building the road and trucking in the precast might not be the most cost efficient.
You can build a small plant to mix the crete wherever you like.
Either way it ain’t gonna be cheap.
The road on top of the berm is the truck road. Come in, the crane takes the load off, the truck leaves. A continous line all pointed the same way.
And yup, would need a batching plant to pour the footings. I would say rebar pounded down some 20 to 30 feet into the ground. Why that far? Because them dirt bags like to tunnel and motion sensors can be hooked on that rebar.
I dont think it would be that expensive. Dam good CCC projects were done real quick back in the 30s. Even the Hoover dam was one of the greatest public works projects and that was done, I believe, ahead of schedule and under budget if I remember right.
Got to remeber that this is largely in the desert. I have seen concrete poured down here and even as it sets it cracks.
That is why I favor the pre cast done somewhere in a building that is climate controled. The sheets, or whatever they call them, cant be that wide. pre fitted with to fit with each other. Round Tounge and groove. They can be grouted after they are set.