A comprehensive study was made of the earthquake resistance of prefabricated highway tunnels embedded into soft undersea soil deposits to establish design methodology for providing adequate structural resistance to seismic disturbances. Measurements of seismic motions were carried out employing downhole accelerometers at three sites around Tokyo Bay, and dynamic analyses were conducted by utilizing seismic records obtained and applying the multi-reflection theory. Model experiments and dynamic analyses on the dynamic response of a highway tunnel embedded in soft soil deposits were also conducted. The following conclusions were drawn: (1) accelerations at deeper locations of soft soil deposits are small in comparison with the surface accelerations, and shapes of vertical distribution of maximum accelerations are different among various earthquakes; (2) the multi-reflection theory may be employed satisfactorily in estimating seismic response of multi-layered subsoils, provided that soils properties, primarily elastic moduli, are appropriately evaluated; (3) for estimating three-dimensional behavior of long structures embedded in soft subsoils during earthquakes, model experiments would be effective, and in the model experiments gelatin can be advantageously used as soft soil; (4) dynamic analyses by means of the finite element method would be also effective in obtaining seismic response of underground structures; and (5) deformation of soft soil deposits has significant effects on the dynamic behavior of the embedded structures, and soil deposits in resonance to seismic motions might exert the structures into critical state, and furthermore, the structures would be affected extensively in the vicinity of a site where depth of soft soil deposits varies steeply due to the fact that the deformation of deeper soil deposits is larger than that of the other section.

  • Supplemental Notes:
    • Papers of International Conferences 1972-1974.
  • Corporate Authors:

    Public Works Research Institute

    2-28-32 Honkomagome, Bunkyo-ku
    Tokyo,   Japan 

    Public Works Research Institute

    2-28-32 Honkomagome, Bunkyo-ku
    Tokyo,   Japan 
  • Authors:
    • IWASAKI, T
  • Conference:
  • Publication Date: 1975

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: p. 305-315

Subject/Index Terms

Filing Info

  • Accession Number: 00128526
  • Record Type: Publication
  • Report/Paper Numbers: Tech Memo #1023 Pt I
  • Files: TRIS
  • Created Date: May 14 1976 12:00AM