Author Topic: Understanding the dimensional space of caves  (Read 5515 times)

Offline robjones

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Re: Understanding the dimensional space of caves
« Reply #25 on: March 07, 2012, 09:47:42 pm »
Simplon met with a horizontal misalligment of 7.87" over 19,755.52m (apologies for mixed units but thats what Sandstrom gives in 'A History of Tunnelling', London, 1963) = about 0.0000012%. The vertical misalligment was 0.087m. Sandstrom states that "In America, the headings [of modest length tunnels] meet on a dime; if the tunnel is not too long a skilled instrument man will hit the dime's edge."