CONSTRUCTION ACCURACY ESSENTIAL FOR LONDON JUMBO PILES

This article describes the installation of piles in a London contract, where a high level of accuracy was essential because of underground railways passing close to the piles. A summary of technical information regarding the piles, which involved a bored volume of 220 cu. M and a concreted volume of 160 cu. M for each unit, is followed by details of the pile layout. This involved three rows each of five piles at 5.9M centres, spaced at 12.6M and 10.9M respectively. The distance between the pile shafts and one railway being a little over 1 metre. Because of the accuracy requirements full-depth permanent steel liners of 12.5 mm wall thickness were used, two telescoping lengths being used for each hole. The tolerance on the centreline was + or - 75mm at ground level and + or - 25mm at a depth of 22.5M. The article continues with a brief account of the grouting of the annulus between lining and hole and the belling operation. Details are also given of the heavy reinforcement used in the concrete, which was carried out as a continuous process. The remainder of the article gives details of the instrumentation used, which included a sensitive inclinometer which makes use of a cantilever strip with a heavy pendulum mounted at one end and the other rigidly fixed in relation to the reference plane, and a fully temperature compensated Wheatstone bridge monitoring four strain gauges. The repeatability of the instrument is reported to be better than + or - 1 microstrain. /TRRL/

  • Availability:
  • Corporate Authors:

    Foundation Publications Limited

    7 Ongar Road
    Brentwood CM15 9AU, Essex,   England 
  • Publication Date: 1974-11

Media Info

  • Features: Figures; Photos;
  • Pagination: p. 33-37
  • Serial:
    • GROUND ENGINEERING
    • Volume: 7
    • Issue Number: 6
    • Publisher: EMAP CONSTRUCT LIMITED
    • ISSN: 0017-4653

Subject/Index Terms

Filing Info

  • Accession Number: 00098133
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Nov 5 1975 12:00AM