SPECIALIZED DRILL BIT FOR DEEP HOLE INVERTED T-SHAPED PILE AND FORMATION METHOD THEREOF

摘要

A specialized drill bit for a deep hole inverted T-shaped pile has a drill bit body (1) provided at the bottom of a drill pipe (12) and formed by a plurality of conical cutting bits (13) spaced from one another; a fixed support (10) provided in the hollow central part of the drill bit body (1), with an upper sliding piece moving up and down using the fixed support (10) as a limiting track; a base plate (11) connected to the lower end of the fixed support (10), with the base plate (11) being butted against the upper sliding piece by a spring (5); and an expanding edge drill (2) with its tail end pivotally connected to the outer periphery face of the upper sliding piece, with the outer surface of the lower part of the conical cutting bit (13) being pivotally connected with a rotatable cutting sleeve (3) and the other end of the expanding edge drill (2) passing through the cutting sleeve (3). The bottom end of a solid steel column (8) in the drill pipe (12) is connected to the upper sliding piece. Also disclosed is a method for forming a deep hole inverted T-shaped pile using the specialized drill bit. The drill bit and formation method increase the bearing capacity of such piles, reduce material costs and construction costs, and can form an inverted T-shaped pile in a deep hole at a building foundation.