The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . on the CentralLondon railway, and one ^2 ft. 4 in. in diameter and only9 ft. 3 in. long was used for a short distance on the Claphamextension of the City and South London railway. general, the upper half of the tunnel was executed first (figs. 9and 10) and the lower part completed by underpinning. Figs. II, 12 and 13 illustrate a case of tunnelling near impor-tant buildings in Boston in 1S96, with a roof-shield 29 ft. 4 in, inexternal diameter. The vertical sidcwalls were first made insmall drifts
The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . on the CentralLondon railway, and one ^2 ft. 4 in. in diameter and only9 ft. 3 in. long was used for a short distance on the Claphamextension of the City and South London railway. general, the upper half of the tunnel was executed first (figs. 9and 10) and the lower part completed by underpinning. Figs. II, 12 and 13 illustrate a case of tunnelling near impor-tant buildings in Boston in 1S96, with a roof-shield 29 ft. 4 in, inexternal diameter. The vertical sidcwalls were first made insmall drifts, the roof-shield running on top of these, and thecore was taken out later and the invert or Boor of the tunnelput in last. Each hydraulic press of the shield reacted againsta small continuous cast-iron rod imbedded in the brick some large sewerage tunnels in Chicago the shields werepushed from a wall of oak planks, 8 in. thick, surrounding thebrick walls of the sewer. tJy^^^/JN—. .!J^*g-WgJ^-»V -U-t-!^^ :~c-^:^V^J^ftiUMim\ij;mMjij-j. J H, V-^-^^^-i. :..Jij,A^>y>^. O^ ^^^Wf ^^r-W-W-^JF^ \^ p^ f^ t^t^i^ i^
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectencyclo, bookyear1910
