(19)
(11) EP 1 041 240 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
02.01.2002 Bulletin 2002/01

(43) Date of publication A2:
04.10.2000 Bulletin 2000/40

(21) Application number: 00106647.1

(22) Date of filing: 28.03.2000
(51) International Patent Classification (IPC)7: E21B 10/44, E21B 17/22
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 30.03.1999 JP 8895599

(71) Applicant: Showa Kensho Co., Ltd.
Mattou-shi, Ishikawa 924-0867 (JP)

(72) Inventors:
  • Matsuzawa, Kazuyuki
    Okaya-shi, Nagano (JP)
  • Miyajima, Masakatsu
    Kanazawa-shi, Ishikawa (JP)
  • Sanai, Masanobu
    Kanazawa-shi, Ishikawa (JP)

(74) Representative: Sajda, Wolf E., Dipl.-Phys. et al
MEISSNER, BOLTE & PARTNER Postfach 86 06 24
81633 München
81633 München (DE)

   


(54) Auger drill


(57) A method of constructing high-friction piles in the ground is provided, wherein the amount of excavated soil from prebored holes can be reduced, and the total number of piles which must be set for a pile foundation can be reduced. An auger is utilized which comprises an elongated shaft (1) and a helical blade (2, 3) extending around the shaft (1) and projecting radially from the periphery of the shaft (1). The shaft comprises a first helical blade (2) along the length of the main portion thereof with an inclination angle in the positive direction of rotation and at least one second helical blade (3) only along the top portion of the shaft (1) with an inclination angle in the opposite or reverse direction as that of the first helical blade (2). When drilling such an auger into the ground, the agitated soil is thrust sideways into the ground so that a plastic zone (A) is formed around the hole up to a prescribed range. Next, a hardening agent (4) is poured into the hole, and then a support or reinforcement material (5) is inserted into the hardening agent (4) before the hardening agent (4) hardens completely. The support material (5) and the plastic zone (A) surrounding the hole form together a monolithic pile.






Search report