The results are presented of measurements made in connection with a 12 m deep braced excavation (in the construction of a railway tunnel) where ground conditions consist of 3 m fill overlying clay which is quick below 9 m. depth. The approximately 11.5 m wide and 12 m deep excavation required for the tunnel was designed with steel bracing spaced 1.7-2.0 m vertically and 3.0 m horizontally. The instrumentation is briefly described, and pore pressure, lateral displacement, settlement, earth pressure and strut load measurements are discussed. Good correspondence between measurements was noted. Due to the large stiffness of the sheet pile wall, close vertical spacing between struts, preloading of struts, and the construction of concrete beams below bottom grade, horizontal deformations of the sheet pile wall were small. Several months elapsed before the high excess pore pressure set up in the quick clay during the driving of the sheet piles dissipated. Such dissipation together with drainage led to settlements that were more than twice as large as the horizontal deformations. The resultant earth pressures on the outside face of the wall compares favorably with the theoretical earth pressure computed on the basis of the triaxial compression test.

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  • Corporate Authors:

    Norwegian Geotechnical Institute

    P.O. Box 40 Tasen
    Oslo 8,   Norway 
  • Authors:
    • Karlsrud, K
    • Myrvoll, F
  • Publication Date: 0

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Filing Info

  • Accession Number: 00148804
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 31 1977 12:00AM