The economical drilling range for the machine being used on the M25 orbital motorway at enfield is from 18 in (457 mm) to 9 ft (2.74 M) diameter and for depths up to 110 ft (33.5 M). The unit contains a hydraulic slide, with 1.22 M of travel for positioning and a hydraulic swing for alignment and dumping of spoil away from the hole. The mast accommodates a triple telescopic kelly bar, to give good drill depths. One of the six piled structures on the motorway involves a total of 58 piles, 18 for the abutments and 40 for the two piers. The structure required vertical and 1 in 6 raked piles up to 20 M deep. After open-hole augering at 600 mm, a full depth reinforcing cage made up of12 x 32 mm mild steel bars, helically bound was inserted and the shaft filled with ready-mix cement. To ensure a minimum of settlement, a driven cast in situ technique was adopted for an aquaduct over the motorway. A fundex rig was used to drive a tube a further 1 M or more down a pre-bored 15-16 M augered hole. Similar reinforcement and concreting was used. An outline is given of other possible configurations and operating modes of the rig. The supplement geodrilling also contains the following articles: looking for future energy beneath the past, and: versatile drill rigs designed for mobility. (TRRL)

  • Availability:
  • Corporate Authors:

    Foundation Publications Limited

    7 Ongar Road
    Brentwood CM15 9AU, Essex,   England 
  • Publication Date: 1980-10

Media Info

  • Features: Photos;
  • Pagination: p. 37-43
  • Serial:
    • Volume: 13
    • Issue Number: 7
    • ISSN: 0017-4653

Subject/Index Terms

Filing Info

  • Accession Number: 00334995
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Sep 16 1981 12:00AM