The invention discloses a special
drill bit for a tapered hole and an application method of the tapered hole. The special
drill bit for the tapered hole consists of a
drill handle, a blade face, a positioning ring and a flexible limit ring, wherein the drill
handle and the blade face are integrated as a whole; the positioning ring and the flexible limit ring which are also integrated as a whole are sleeved on the drill
handle; the included angle formed by the outer line of the blade face and the axial line of the
drill bit is an
acute angle; and the blade face is embedded with a semi-
spiral blade edge, and the top end of the blade edge is a blade tip. The application method comprises the following steps: (1) pressing an expansion type special
anchor bolt with a nylon sleeve into a tapered
anchor bolt hole, so that the geometry formed after expansion of the expansion type special
anchor bolt is matched with the tapered anchor bolt hole, and the surface of the anchor bolt can be tightly combined with the tapered hole to achieve anchoring effect; (2) drilling an opening on the root part of a required rib, inserting the rib into a tapered bar planting hole, expanding the opening of the rib with a wedge to form a tapered shape, and injecting anchor
adhesive, so that the bar planting surface and the tapered hole can be tightly combined after solidification. The tapered hole drilled by the
drill bit of the invention can significantly improve the anchorage strength and the bar planting
solidity, and greatly enhance the pre-tightening force,
bearing capacity, pull-out resistance and tensile
bearing capacity of anchors or planted bars.