A method is presented here which allows computation of the drain spacing for cases with and without smear, and a technique is described for the analysis of settlement data that determines the coefficient of consolidation from settlement data alone. Soil disturbance during drain installation is also discussed. The theory of rapid design computations is detailed, as well as design with intermediate drainage layers. Sand drains are constructed by making a vertical hole on the clay and filling the hole with sand. The horizontal layout of the drains is usually a pattern of squares and triangles with one drain at each node. The maximum drainage distance within the pattern is approximately one-half the spacing between drains. The spacing between drains, thickness of deposit, and the consolidation properties of the soil regulate how fast the consolidation settlements will acccur. Sand drain spacing should be optimized by designing for both the radial flow to the drain and the vertical flow. By conventional methods, design optimization requires either a trial and error procedure or the construction of graphs for a particular design. Design charts are presented that assist in computing the drain spacing explicitly for most cases. Diligent observation of the field instrumentation and subsequent data analysis is an important aspect of sand drain installations.

  • Corporate Authors:

    University of Connecticut, Storrs

    Department of Civil and Environmental Engineering, 261 Glenbrook Road
    Storrs, CT  United States  06269-2037
  • Authors:
    • Long, R P
  • Publication Date: 1975-7

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 30 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00149356
  • Record Type: Publication
  • Report/Paper Numbers: C.E. 75-93
  • Files: TRIS
  • Created Date: Aug 15 1977 12:00AM