VIBRATING BEAM INJECTS THIN CUTOFF WALLS

A cost-saving 10-year-old European method is described in which Bentonite-cement slurry flows through 2 pipes to three jets at the bottom of a vertical steel I-beam. A 17-ton French-made vibrating hammer sinks the beam into sandy soil and slurry is injected to lubricate the beams downward path. The wall is built as the beam is pulled back up, because more slurry is injected during withdrawal, as it flows under the void left by the beam on the way up. Upon completion of one 40-inch-ling section, the crane backs up and repeats the cycle. In 45-ft depths, the machine can put down about 90-ft of wall in a 24-hour day. The key to the process is the 50-ft long injection beam which is a 33-inch, wide-flange section that weighs 190 lb per ft. Two pipes run along its length and connect to three nozzles at the bottom that are evenly spaced across the 33-inch width. The beam's web carves out the spice of the wall and the flanges stabilize it during the 900 to 1,200 vibrations per minute delivered to its top. To ensure continuity in the wall, each time the crane backs up and the beam is lowered, it overlaps the last section by 18 in., the width of 14-in. fin plus 4 in. of beam. The steel fin, welded to the flange and pointing away from the crane travel cuts a groove in the last-placed section of wall, allowing fresh liquid to be injected. Two rigs working 6-day weeks, 24 hours a day, have progressed about 4,200 sq ft of wall per machine per 24-hour shift. The cost of the entire outfit is $600,000.

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  • Corporate Authors:

    McGraw-Hill, Incorporated

    330 West 42nd Street
    New York, NY  United States  10036
  • Publication Date: 1975-11-27

Media Info

  • Features: Photos;
  • Pagination: p. 19
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00128809
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 29 1976 12:00AM