DEFORMATIONS OF THE BOTTOM OF AN EXCAVATION IN CLAY. FIELD MEASUREMENTS AND EVALUATION OF THE RESULTS

DEFORMATIONER I EN SCHAKTBOTTEN AV LERA. FAELTMAETNINGAR OCH UTVAERDERING AV MAETRESULTAT

When the overburden pressure is removed, there is a change in the equilibrium and stress conditions in soft clay. As A result, the shear stresses are changed. On the basis of present knowledge, the deformations or their components, change in shape and change in volume, cannot be estimated, nor can the time dependent growth in deformation be determined. For practical reasons, it is necessary to predict whether the deformation at the bottom of a deep excavation can be tolerated in view of settlements after construction of foundations and backfilling. In order to obtain more information concerning the relationship between heave and consequent settlement around deep excavations inside sheet piling, measurements were made of vertical movements inside and outside the sheeting, and deflections in the sheeting, during excavation and after construction of foundations. A rough idea of a clay's susceptibility to creep can be gained from test results. An expression is proposed whereby the boundaries between elastic and plastic deformation can be determined. It is suggested that when the bearing factor n is less than 4, elastic heave of 0.5% of excavation depth occurs, while when n is above 4, time dependent heave up to 2% of depth takes place. /TRRL/

  • Corporate Authors:

    Statens Raad Foer Byggnadsforskning

    St Goeransgatan 66
    Stockholm,   Sweden 
  • Authors:
    • MAGNUSSON, O
  • Publication Date: 1975

Language

  • Swedish

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: 87 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00133712
  • Record Type: Publication
  • Source Agency: Swedish National Road and Transport Research Institute (VTI)
  • Report/Paper Numbers: R21:1975
  • Files: ITRD, TRIS
  • Created Date: Sep 4 1976 12:00AM