caissons

It distinguishes between box caissons and open caissons.

The John Hancock building has some of the deepest caissons of any building in the world into bedrock.

Then you have to create very strong concrete caissons to hold the building up, standing on that limestone layer.

People have been building structures below the water table for hundreds of years using cofferdams and caissons.

When the Brooklyn Bridge was built and workers were being crippled or killed by the bends down in the caissons...

Hour by hour the caissons reach down to the rock of the earth and hold the building to a turning planet.

Or the same caisson unable to erect because the caissons themselves are covered in silt...

Slap one downstream of one of the caissons of the Verrazzano-Narrows Bridge.

Then use caissons and hyperbaric chambers; Mine the old fashioned way.

Well, the concrete that actually takes all the load would be safe; that's how pretty much any caissons or foundations in water are built anyway.

Digging down to any deposits of other rock are going to require either significant effort in terms of dewatering, caissons, and equipment or else mining underwater.

I wonder what state the concrete caissons are in.

I think the original was supposed to be to the music from "The Caissons Go Rolling Along".

My mum was tracing maps for D-Day, and packing munitions and my Aunt did technical drawing on the "mulberry harbour" concrete caissons floated over to the beaches for D-Day.

(Caissons can be built and pumped dry, where earth must be dug.) Perhaps you're thinking of a cooling jacket lining the tunnel bore.