TUNNELING ON LONDON'S VICTORIA LINE UNDERGROUND RAILWAY

TUNNELING IS COMPLETED ON THE VICTORIA LINE UNDERGROUND RAILWAY WHICH WILL FORM A 10.5 MILE ADDITION TO THE EXISTING 215 MILES OF SUBWAY IN LONDON. THERE ARE TWELVE STATIONS ON THE ROUTE, ELEVEN OF WHICH HAVE INTERCHANGE CONNECTIONS TO EXISTING TUBE LINES. THE ENLARGED AREAS AT STATIONS WERE EXCAVATED BY HAND INSIDE CONVENTIONAL SHIELDS. AT CROSSOVER AND STEP-PLATE ENLARGEMENTS HAND MINING WAS CARRIED OUT WITHOUT SHIELDS, SOMETIMES UNDER AIR PRESSURE. THE RUNNING TUNNELS WERE CONSTRUCTED MAINLY WITH MECHANICAL DIGGER SHIELDS. TO SAFE GUARD THE CROWN, WHICH WAS 42 FT BELOW GROUND LEVEL WITH A CLAY COVER OF ONLY 9 FT SEPARATING THE TUNNEL FROM WATER-BEARING GRAVEL, A BLANKET OF GRAVEL WAS GROUTED FROM THE STATION TRACKS AND PLATFORMS OVER THE ENLARGEMENT AREA. THE GROUTING PROCESS STARTED BY DRIVING PIPE FROM GROUND LEVEL INTO THE GRAVEL ON A GRID TWO FT SQUARE. INJECTIONS WERE MADE BY THE JOOSTEN PROCESS - A TWO- SHOT PROCEDURE. THE FIRST INJECTIONS WERE MADE WHEN DRIVING THE RODS AND CONSISTED OF A SODIUM SILICATED SOLUTION. A CALCIUM CHLORIDE SOLUTION WAS INJECTED AS THE RODS WERE WITHDRAWN. JELLING TOOK PLACE ALMOST INSTANTANEOUSLY, FORMING A WEAK MATRIX OF CONCRETE IN THE GRAVEL. CAST IRON RINGS AND PRECAST CONCRETE LININGS WERE USED. EXPANDED BOLTED RINGS ARE USED WHERE THE CLAY IS GENERALLY FIRM BUT WATER IS PRESENT, EITHER FROM SILT SEAMS OR CLAYSTONES.

  • Availability:
  • Supplemental Notes:
    • Vol 37, No 1, PP 40-43, 3 FIG, 5 PHOT
  • Authors:
    • Dodds, G S
  • Publication Date: 1967-1

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  • Accession Number: 00214792
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 1 1970 12:00AM