One involves carving a 150km tunnel through a granite massif which is the Alps in a scale that never before was done in history of mankind, the other involves drilling a tunnel through alluvium and sedimentary deposits pretty much like any medium-scale tunneling work.
One involves carving a 150km tunnel through a granite massif which is the Alps in a scale that never before was done in history of mankind, the other involves drilling a tunnel through alluvium and sedimentary deposits pretty much like any medium-scale tunneling work.