A DEVELOPMENT IN SLURRY TRENCH TECHNIQUE FOR CUT-OFF CONSTRUCTION

A method has been developed for forming an impermeable and comparatively cheap cut-off for a reservoir scheme in England. This method, which has been continuously developed and improved on site and enables impermeable membrances to be formed quickly and economically on suitable ground, consists essentially of mixing in situ sands and gravel with cement, bentonite and water in proportions which will set to the consistency of soft cheese. The cut-off formed is both flexible and impermeable and could have widespread application in other situations. A 600 mm wide trench is excavated through the granular material into London Clay using a cement/bentonite grout. Average depth is about 11 m. The granular material is then mixed with grout and placed back into the excavation. Details of grout mixing, gravity feeding of bentonite slurry, trench excavation, and backfilling are outlined. Trials were carried out on site to prove that the specificed permeability coefficient could be met. In-situ falling head tests were carried out on all panels. Alternative methods (grouted screen technique, and the self-hardening grout technique) which were considered, for this application were about 30 per cent more expensive. Many other applications for this method are possible: by increasing the cement content of the grout the resultant membrane would set to a more rigid consistency and this could enhance the performance of some embankments; control of pollutant flow into underground aquifiers; limit areas affected by a dewatering system.

  • Availability:
  • Corporate Authors:

    Wells (Edward) and Sons, Limited

    143/145 Camberwell New Road
    London SE5,   England 

    Foundation Publications Limited

    7 Ongar Road
    Brentwood CM15 9AU, Essex,   England 
  • Authors:
    • Hetherington, J S
    • Nelders, B
    • PULLER, M J
  • Publication Date: 1975-11

Media Info

  • Features: Figures;
  • Pagination: p. 16-18
  • Serial:
    • GROUND ENGINEERING
    • Volume: 8
    • Issue Number: 6
    • Publisher: EMAP CONSTRUCT LIMITED
    • ISSN: 0017-4653

Subject/Index Terms

Filing Info

  • Accession Number: 00132921
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 5 1976 12:00AM