How Did Engineers Construct Submerged Tunnels Like BART's?

[CrossFit415]

How did engineers manage to build tunnels submerged 100 ft under water without having tunnels collapsing? Say for example, BART, has trains going through these tunnels daily. How did engineers build water tunnels?

 

[JaredJames]

Well my guess would be similar to how they build a submarine and not have it collapse.

I'm not sure what BART is, but most tunnels are drilled through bedrock (http://en.wikipedia.org/wiki/Tunnel_boring_machine) with concrete sections inserted in an arch arrangement to act as reinforcement for the tunnel.

The basics being you simply create a tunnel which is strong enough to withstand the required pressure.

If the tunnel was not drilled, you could create sections and lower them to the bottom of the water and once completed (and as such waterproof) you could simply pump the water out to leave you with a tunnel.

 

[CrossFit415]

I see thanks. Oh BART stands for Bay Area Rapid Transportation located here in Bay Area, California

 

[JaredJames]

I see thanks. Oh BART stands for Bay Area Rapid Transportation located here in Bay Area, California

Yes, I did a bit of Googling to see if they showed whether it was above the bottom of the water or below in bedrock. Apparently not so I can't be more specific in the reply.

 

[CrossFit415]

I did research and engineers prebuilt the tunnel to be submerged under water after completion. By using gravel and rock its holding down the tunnels.

I just thought I found this facsinating. Very interesting to see what we can design. We can design anything we see.. incredible.