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Evening Star, Issue 22458, 1 October 1936, Page 14

The Japanese engineers, directed by Jiro Tachibana, of the Way and Works Bureau of the Japanese Government Railways, face difficulties greater than other tunnel builders have met. Preliminary surveys show they_ will have to bore through nine kinds or rock, and in at least two places through rock faults produced by earthquakes. The tunnel must be „ built flexibly enough to withstand earthquakes (Japan has 4,000 perceptibl® ones each year). The engineers expect tq meet this problem by constructing a'flexible tube of welded steel plates. Most under-water tunnels are made of rigid cast-iron or cast-steel sections. Buried in the bottom of the channel,, the tube must be anchored against tha sweeping action of the tidal_ currents,which may uncover it. This will bo done bv sinking huge concrete blocks at either side. The currents are so swift that the preliminary rock borings could not be made until caissons had been sunk to the bottom to protect the drillers.—' Literary Digest.’-