This article deals with the construction, carrying capacity and applications of a special type of small diameter bored pile (less than 300 mm and normally between 120 and 250 mm) known under such names as root-piles, needle-piles, pali radice, micro piles, or mini piles. Because of the special method of construction during which concrete or mortar is forced into the soil, the pile's carrying capacity is comparatively very high (a 250 mm diameter pile can carry a load of 1.0 mm, in contrast to a 40 cm diameter pile which has an allowable load of only 0.30-0.37 mn.); but even without specific injection, i.e. with only hydrostatic pressure, carrying capacity is still high, perhaps because of the short construction time and small relaxation of the soil around the drilled hole. The construction method for the various types of pile are described, including those for the cast-in-place reinforced concrete type (The hole is drilled, the reinforcement put in place, and then the concrete is added.), anchor type (some of the concrete mortar is added before the reinforcement and injection pipe is added.), the micropile-tubfix type (similar to the preceding, except that the cement suspension via a plug), and the mini-core or Gewi pile (consisting of a 50 mm steel bar asembly incorporating a system of valves and pipes). Their main application is with special repair jobs and in the preservation of buildings and other structurs. They are also used for strengthening existing foundations, for the protection of buildings next to deep excavations, and they can supercede classical underpinning.

  • Availability:
  • Corporate Authors:

    Foundation Publications Limited

    76 Ongar Road
    Brentwood,   England 
  • Authors:
    • Koreck, H W
  • Publication Date: 1978-5

Media Info

  • Features: Figures; References;
  • Pagination: p. 14-20
  • Serial:
    • Volume: 11
    • Issue Number: 4
    • ISSN: 0017-4653

Subject/Index Terms

Filing Info

  • Accession Number: 00178885
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 27 1978 12:00AM