Perhaps the BEST B1G Forum anywhere, here at College Football Fan Site, CFB51!!!

The coastal tunnels can be buried tubes.  The Chunnel probably goes through some limestone.

Tunnel Boring | HRBT Expansion Project


The TBM will launch from the South Island (Norfolk side), and bore (work) at a rate of about 50 feet per day until it reaches the layer of soil known as the Yorktown layer, approximately 50 feet below the current tunnels. The TBM excavates the tunnels with a circular cross section through the soil.  The process will take more than two years. Built specifically for the HRBT Expansion Project, the TBM will be a central component of the project.  

The existing ten tunnels in Hampton Roads are immersed tubes. Advances in tunnel technology make the bored-tunnel approach desirable for the expansion project. The method has fewer environmental impacts and does not disrupt Navy, marine, or commercial traffic in the busy federal channel.

The Yorktown Formation is a mapped bedrock unit in the Coastal Plain of Maryland, Virginia, North Carolina and South Carolina. It is overconsolidated and highly fossiliferous.

Much of that part of Florida is coastal deposits from sea sediment. Not much limestone on that coast, from what I understand, and to reach bedrock you have to go pretty deep. Florida came together as three pieces. The North was connected to the USA mainland. The middle and South slammed into each other and the North in tectonic movement.

It kinda looks like this:

For sure, it's a standard part of transportation between England and the mainland now.  You don't hear about it, because it's no longer being built.  It's just a set of train tracks now.  That go underwater.

and we don't hear about it because it doesn't have alarming problems and safety issues

I was surprised to read the Hampton tunnels are just buried tubes.  I've driven through them a few times.

I can imagine limestone also isn't much of a structural material inside which a tunnel could hold without concrete.

Engineers are pretty awesome, or at least, engineering is.  When I was a kid, I wanted to be either an architect or a civil engineer.  And guess where I wanted to go to school?

Tech?  Lubbock seems a long way off for a boy from Georgia...

Tech?  Lubbock seems a long way off for a boy from Georgia...

I think the top engineering schools are something like MIT, CalTech, Purdue, and Georgia Tech (which officially is GIT of course).

I started chatting with profs at UGA about where to go to grad school and most of the names were, to me, like a foreign country.  I had not traveled much back then.

Now I've been to 49 states.

I think the top engineering schools are something like MIT, CalTech, Purdue, and Georgia Tech (which officially is GIT of course).

Stanford, the Cals, Washington, Texas, A&M, most of the B1G (IU does not have engineering), some of the Ivy's, Carnegie, Hopkins, the USC.

Yep... As much as I brag on Purdue, there are some very fine engineering schools in the B1G. I'd say Illinois, Michigan, and Purdue are the top of the heap (probably distinguished more based on which is stronger in each sub-domain of engineering rather than any overall differences), but even those not on that list are extremely good schools (minus IU of course).

UC-Boulder is definitely up there too.