There has been an unusual application of pre-packed 'sandwick' drains on a half constructed embankment of the A256 Sandwich bypass. It was discovered that pore water pressure on the alluvium beneath the embankment was not dissipating as quickly as expected. Vertical sand drains were found to be necessary to provide a further drainage path for the pore water upwards into a 0.5 M drainage blanket at the base of the embankment. Cementation's design using a 65 mm diameter woven-polypropylene stocking was used. The site-filled drains were inserted in previously prepared pores drilled through the half constructed embankment and the alluvium to the thanet sands 9 M below. The spacing of the sand drains, important to their efficient operation, varied from 3.5 M at the start of the embankment to 0.8 M at the viaduct abutment. /TRRL/


  • English

Media Info

  • Features: Figures; Photos;
  • Pagination: p. 18
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00184462
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Monograph
  • Files: ITRD, TRIS
  • Created Date: Jan 13 1979 12:00AM