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THE USUAL METHOD OF CUT-AND-COVER SUBWAY CONSTRUCTION COULD NOT BE PERFORMED UNDER SAN FRANCISCO'S MARKET STREET. DEWATERING THE SITE WOULD HAVE PERMITTED PEAT LAYERS TO COMPRESS, WHICH WOULD HAVE INDUCED SUBSTANTIAL SETTLEMENTS AND CAUSED STRUCTURAL DAMAGE IN NEARBY BUILDINGS. THE ALTERNATIVE CHOSEN WAS TO EXCAVATE WITHIN A STRONG WATERTIGHT WALL, COMBINED WITH GROUNDWATER RECHARGE OUTSIDE THE WALL. SEEPAGE UNDER THE SUBWAYSTATION WALLS WAS CONTROLLED BY EXTENDING THE WALLS BELOW EXCAVATION LEVEL AT LEAST 20 FT. OR INTO ONE OF THE CLAY LAYERS. THIS METHOD WAS CALLED SOLDIER PILE TREMIE CONCRETE. THE METHOD IS OUTLINED. STOPPING SUBSIDENCE OF LAND OVER MINES IS DESCRIBED IN THE SCRANTON AND PITTSTON AREAS OF PENNSYLVANIA. HYDRAULIC BACKFILLING IS UNDER WAY ON A LARGE SCALE TO PREVENT FURTHER SUBSIDENCE. ALTHOUGH SAND IS A PREFERRED MATERIAL FOR BACKFILLING BECAUSE IT PROVIDES GOOD STRATA SUPPORT, COAL-MINE REFUSE AND OTHER MATERIALS ARE OFTEN USED. A SLURRY OF THIS MATERIAL AND WATER IS USED. GROUT-GRAVEL COLUMNS ARE USE FOR BUILDING OVER MINED AREAS IN THE PITTSBURGH AREA. THE GROUT-GRAVEL COLUMN IS PRESENTED IN DETAIL.

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  • Supplemental Notes:
    • Vol 38, No 11, PP 32-33
  • Publication Date: 1968-11

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  • Accession Number: 00215227
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 29 1994 12:00AM