2007-01-04 07:34:12 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Earth Sciences & Geology
There are many components to underwater subway construction, but the key is the tunneling shield, a machine that made digging through water-bearing strata both safe and possible. The shield was pioneered in 1818 by Marc Isambard Brunel, a French naval officer living in England who noted how shipworms bore through wood, pushing sawdust behind them with the aid of their shell armor.
See the link below for more info. Cheers!
2007-01-04 07:47:40 · answer #1 · answered by krodgibami 5 · 0⤊ 0⤋
See http://en.wikipedia.org/wiki/Channel_Tunnel for "The Channel Tunnel (French: le tunnel sous la Manche) is a 31 mile (50.5 km)-long rail tunnel beneath the English Channel at the Straits of Dover, connecting Folkestone, Kent in England to Coquelles near Calais in northern France."
See http://en.wikipedia.org/wiki/Tunnel_boring_machine for "Tunnel boring machines (TBM) are used to excavate tunnels with a circular cross section through a variety of geologies. They can be used to bore through hard rock or sand and almost anything in between."
2007-01-04 15:47:52 · answer #2 · answered by Robert W 4 · 0⤊ 0⤋