That cover dirt materially adds to the resistance of the structure.

This is why even above-ground bunkers are almost always buried underneath a giant mound of dirt instead of being bare concrete. It is a cheap structural multiplier that greatly increases the amount of explosive required to damage the insides. It is also very cheap. A bunker buster is a very heavy and specialized munition which limits its scope of practicality.

There are entire civil engineering textbooks that focus exclusively on the types of scenario you are alluding to. It is a very mature discipline and almost all of it has been tested empirically.

I used to have a civil engineering textbook that was solely about the design of structures to resist the myriad effects of nuclear weapons. It was actually pretty damn interesting. Civil engineers have contemplated at length just about every structural scenario you can imagine.

> Civil engineers have contemplated at length just about every structural scenario you can imagine.

I bet. Do they recommend cut and cover highways in contested environments? Or do they recommend shooting back until the area is no longer contested? (Which you practically have to do anyway to build the cut and cover tunnel in the first place.)

I don’t doubt that it is a good idea to cover with earth C&C bunkers and launchers and such. But those are point installations. Miles and miles of tunnels used for logistics are lines. They scale very differently.