Micropile foundation structure and construction method of micropile foundation

摘要

The present invention relates to a micropile foundation structure and a construction method of a micropile foundation. According to the present invention, the micropile foundation structure is configured such that a soft ground is perforated, a steel bar is installed in the perforation, an injection material, commonly referred to as a grout fluid, is injected, and thus, a load of a structure transmitted through the steel bar can be transmitted to a firm lower ground through the injection material. According to the present invention, the micropile foundation structure comprises: a hollow mounting portion installed in the lower ground after or at the same time when the ground is perforated to transmit a load transmitted from an upper portion to the adjacent ground and having an outer diameter smaller than the diameter of the perforation; a hollow transmission portion connected to an upper end of the mounting portion to transmit the upper load transmitted from the upper portion to the mounting portion, extended to be exposed above the surface of the earth, and having an outer diameter smaller than the diameter of the perforation; one or more ring or C-shaped reinforcing structures provided on an outer surface of the transmission portion to reinforce the same; a blocking portion having a blocking means, which is protrudingly coupled to a circumference of an upper outer side of the mounting portion to prevent soil dust fallen from a transmission portion outer space from entering a mounting portion outer space, wherein the mounting portion outer space exists between an outer surface of the mounting portion and a hollow wall of the lower ground; the injection material filling a space in the perforated hollow wall to integrate the mounting portion with the adjacent ground; and a foundation portion of a reinforce concrete material formed to have a loading portion to be embedded therein.