JP6506538B2 - Drilling method of concrete structure - Google Patents

Description

  The present invention relates to a method of drilling a concrete structure, and more particularly to a method of drilling a cylindrical hole having a diameter-increased portion at the bottom thereof in a concrete structure.

  Reinforcement work is known, in which a cylindrical hole is drilled in a concrete structure with a drill, etc., and an anchor material such as rebar is inserted there, and a post-filling material such as grout material or resin is injected and fixed. If the inner surface of the cylindrical hole is smooth, the anchor material has insufficient fixing strength, and the anchor material may come off the concrete structure when an excessive external force is applied (Patent Document 1).

  On the other hand, insert the drilling rod into the bottom of the cylindrical hole opened in the ground, expand the diameter-enlarging bit provided on the head of the drilling rod, and rotate the drilling rod to form the diameter-expanding portion at the bottom of the pilot hole A method has been proposed in which concrete is cast in this hole to form a concrete pile having a high pullout resistance (Patent Document 2).

JP 2012-177222 A Unexamined-Japanese-Patent No. 07-268867 gazette

  However, since the diameter expansion method described in Patent Document 2 enlarges the diameter-expanding bit of the head and rotates it to expand the diameter of the bottom of the pre-drilled hole in the ground, if this is applied to drilling of a concrete structure, The attitude of the rod was not stable and diameter expansion was difficult.

  An object of the present invention is to provide a method of drilling a concrete structure which can reliably open a cylindrical hole having an enlarged diameter portion at the bottom in the concrete structure.

  Therefore, in the method of drilling a concrete structure according to the present invention, a cylindrical hole having an enlarged diameter portion at the bottom is formed in the concrete structure, the inner diameter of the concrete structure having an inner diameter equal to that of the cylindrical hole. Forming the first drive shaft rotatably at the base portion and foldably connecting the second drive shaft to the tip end of the first drive shaft and biasing the second drive shaft in the bending direction The enlarged drill is inserted into the pilot hole using the drill, and the base is brought into contact with the inner surface of the pilot hole to maintain the posture of the drill, and the second drive shaft is biased by a biasing force. An enlarged diameter portion is formed at the bottom of the pilot hole by bending the drive shaft and pressing the diameter-increasing bit attached to the second drive shaft against the bottom of the pilot hole and driving the first drive shaft. Characterized in that it comprises a process

  One of the features of the present invention is that the base of the drilling drill is brought into contact with the lower hole to stabilize the posture of the drilling drill, and the diameter of the bottom of the lower hole is expanded in that state.

  As a result, it is possible to make an enlarged hole at the bottom of a concrete structure that is harder than the ground, and for example, when an anchor material is inserted and fixed in the hole, high pullout resistance can be obtained.

  Although the base of the enlarged diameter drill is brought into contact with the inner surface of the pilot hole in the above description, the posture of the diameter expanded drill may be stabilized by bringing the expanded diameter drill itself into contact with the inner surface of the pilot hole. Therefore, in the method of drilling a concrete structure according to the present invention, a cylindrical hole having an enlarged diameter portion at the bottom is formed in the concrete structure, the inner diameter of the concrete structure having an inner diameter equal to that of the cylindrical hole. Forming a cam and an operation shaft in a drill main body having an opening on the side wall of the tip end portion, and mounting an excavating bit rotatably in the opening while squeezing the enlarged diameter drill The drill bit is inserted by inserting the drill into the pilot hole, maintaining the posture of the drill by contact with the inner surface of the pilot hole, and operating the operation shaft to rotate the cam. And a step of forming an enlarged diameter portion at the bottom of the pilot hole by making the drill body project from the opening against the biasing force and rotationally driving the drill body.

It is a figure which shows typically the preferable embodiment of the drilling method of the concrete structure which concerns on this invention. It is a figure which shows typically one example which fixes an anchor material to the hole which opened in the said embodiment. It is a figure which shows typically the state which looked at the state of FIG. 2 from the plane. It is a figure which shows typically the drilling method by 2nd Embodiment. It is a figure which shows the side structure of the front-end | tip part of the diameter-expansion drill used in the said embodiment. It is a figure showing the plane composition of the above-mentioned diameter expansion drill.

  Hereinafter, the present invention will be described in detail based on specific examples shown in the drawings. 1 to 3 show a preferred embodiment of the method for drilling a concrete structure according to the present invention. When a cylindrical hole is made in a concrete structure, as shown in FIG. 1A, the pilot hole 21 is made in the concrete structure 20 using a drilling drill 40 or the like. The pilot hole 21 has an inner diameter substantially equal to the cylindrical hole to be drilled.

  When the pilot hole 21 can be formed, as shown in (b) of FIG. 1, the diameter-expanding drill is inserted and set in the pilot hole 21. In this enlarged diameter drill, the first drive shaft 10 is rotatably inserted in the base 11 having an outer diameter equal to the inner surface of the pilot hole 21, and the second drive shaft 12 is foldably connected to the tip of the first drive shaft 10. While the diameter-enlarging bit 13 is fixed to the second drive shaft 12, a spring member 14 is interposed between the first and second drive shafts 10 and 12.

  When the diameter expansion drill can be set, the diameter expansion bit 13 is pressed against the inner surface of the bottom of the pilot hole 21 with the second drive shaft 12 bent with respect to the first drive shaft 10 by the biasing force of the spring member 14 When the first drive shaft 10 is rotated, the diameter-enlarging bit 13 expands while digging the inner surface of the bottom of the pilot hole 21 and, as shown in FIG. 1C, the diameter of the bottom of the pilot hole 21 is enlarged The portion 22 can be formed.

  When the cylindrical hole 21 having the enlarged diameter portion 22 is thus obtained, for example, as shown in FIGS. 2 and 3, the retaining member 23 is inserted into the enlarged diameter portion 22, and the anchor between the retaining members 23 is inserted. Insert the material, cast the concrete, solidify the concrete, you can firmly fix the anchor material.

  4 to 6 show a second embodiment. When a cylindrical hole is made in a concrete structure, as shown in FIG. 4A, the pilot hole 21 is made in the concrete structure 20 using a drilling drill 40 or the like. The pilot hole 21 has an inner diameter substantially equal to the cylindrical hole to be drilled.

  When the pilot hole 21 can be formed, as shown in (b) of FIG. 4, the diameter-expanding drill is inserted and set in the pilot hole 21. In this enlarged diameter drill, as shown in FIGS. 5 and 6, the drill body 30 has an inner diameter equal to the inner surface of the pilot hole 21, and the drill bit 31 is fixed to the tip of the drill body 30, An opening is formed on the side surface of the distal end portion of the main body 30, and an enlarged diameter bit 34 is rotatably attached to the opening about a vertical shaft 34A, a spring member is provided on the shaft 34A, and the diameter enlarged bit 34 is embedded It is rotationally biased in the direction.

  Further, a cam 33 and an operation shaft 32 are built in the drill main body 30, a concave cam surface 33A is formed on the cam 33, and the diameter-enlarged bit 34 can be accommodated in the cam surface 33A.

  When the diameter expansion drill can be set, when the operation shaft 32 is gradually rotated, the diameter expansion bit 34 is pushed out and rotated by the cam surface 34A, is protruded from the opening and pressed against the inner surface of the bottom of the pilot hole 21, and diameter expansion is performed. When the drill is driven, the enlarged diameter bit 34 excavates and expands the inner surface of the bottom of the pilot hole 21 so that the diameter enlarged portion 22 can be formed at the bottom of the pilot hole 21.

  In this way, when the cylindrical hole 21 having the enlarged diameter portion 22 is obtained, the anchor material is inserted, concrete is poured, and when the concrete is solidified, the anchor material can be firmly fixed.

DESCRIPTION OF SYMBOLS 10 1st drive shaft 11 base 12 2nd drive shaft 13 diameter expansion bit 20 concrete structure 21 pilot hole 22 diameter expansion part 30 drill main body 32 operation shaft 33 cam 34 diameter expansion bit

Claims (2)

In a method of forming a cylindrical hole having a diameter-increased portion at the bottom in a concrete structure,
Forming in the concrete structure (20) a pilot hole (21) having an inner diameter equal to the cylindrical hole;
The first drive shaft (10) is rotatably supported on the base (11) of the same outer diameter as the inner surface of the pilot hole (21), and the second drive shaft (12) is mounted on the tip of the first drive shaft (10). The diameter-expanding drill is inserted into the pilot hole (21) using a diameter-expanding drill which is foldably connected and the second drive shaft (12) is biased in the bending direction, and the base (11) is The posture of the diameter expanding drill is held in contact with the inner surface of the pilot hole (21), and the second drive shaft (12) is bent with respect to the first drive shaft (10) by the biasing force, the second drive shaft The diameter-expanding bit (13) attached to (12) is pressed against the inner surface of the bottom of the pilot hole (21), and the first drive shaft (10) is rotationally driven to expand the bottom of the pilot hole (21). Forming the diameter portion (22);
The drilling method of the concrete structure characterized by having. In a method of forming a cylindrical hole having a diameter-increased portion at the bottom in a concrete structure,
Forming in the concrete structure (20) a pilot hole (21) having an inner diameter equal to the cylindrical hole;
While incorporating an operation shaft cam (33) (32) having a concave cam surface to the lower hole (21) inner surface equal to the outer diameter of the drill body (30) that having a opening in the front end portion sidewalls (34A) The drill bit (34) is housed in the concave cam surface (34A) using the enlarged diameter drill rotatably attached to one end of the drill bit (34) in the opening and pivoted in the insertion direction . In this state, the drill main body (30) of the enlarged diameter drill is inserted into the lower hole (21) and the outer surface of the drill main body (30) is brought into contact with the inner surface of the lower hole (21) to maintain the posture of the expanded diameter drill and, by rotating the operation shaft (32) against the biasing force of the other end of the drill bit (34) by the said cam (34) projecting from said opening, said drill body (30) the drill bit by rotating the ( Forming enlarged diameter portion (22) in the bottom of the pilot hole (21) by the other end of the 4),
The drilling method of the concrete structure characterized by having.

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