JP2005271230A - Excavation method and hole excavating jig - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excavation method capable of easily and certainly performing excavation work when a cavity hole is excavated around an anchor bolt using a core drill to contribute to the practicality of a repairing method of a foundation for a structure. <P>SOLUTION: A core drill 30 constituted by providing a rotary body 42 rotatable with respect to the protruded part on the side of the screw part of the anchor bolt 3 embedded in foundation concrete 2 in a state extruded upward on the side of the screw part and mounting a bottomed cylindrical core bit 32 on the leading end of an electromotive drill 31 is prepared. The core bit of the core drill is externally fitted to the rotary body in state having a play to excavate a cylindrical hole by the core drill while positioning the core bit. Thereafter, the inside of the cylindrical hole is crushed to excavate the cavity hole. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an excavation method and a hole excavation method used when repairing a structural foundation for installing a lighting column, a sign post, a soundproof wall, or a building structure on a concrete rail of a bridge or a road shoulder. Concerning ingredients.

  In general, when installing a columnar structure such as a lighting column or a sign column on a concrete railing of a bridge, for example, as shown in FIGS. 5 to 7, a foundation as an installation stand provided on the shoulder side of the railing 1. A plurality of (four in the figure) anchor bolts 3, 3,... Are embedded in the concrete 2 with their thread portions 3a projecting upward, and columnar structures with respect to the thread portions 3a of the respective anchor bolts 3. A bolt hole 6 provided in the base plate 5 is externally fitted and a nut 7 is screwed and fastened from above. In FIG. 5, reference numeral 10 denotes a sound insulation wall installed on the upper surface of the rail 1, and the sound insulation wall 10 is provided with an inspection port 11 that can be opened and closed corresponding to the installation location of the columnar structure 4. In FIG. 6, 12 is a frame for connecting adjacent anchor bolts 3, 3, and 13 is a mortar material that covers the gap between the upper surface of the foundation concrete 2 and the base plate 5 of the columnar structure 4.

  By the way, although the life of the anchor bolt 3 has been conventionally considered to be almost permanent and comparable to that of the foundation concrete 2, the columnar structure 4 has recently been used for a foundation for a columnar structure that has been several decades after construction. When the base plate 5 of the base plate 5 was removed and inspected, there was no problem in the portion screwed with the nut 7 of the anchor bolt 3, but the portion exposed from the upper surface of the foundation concrete 2 below that portion, that is, the bolt hole of the base plate 5 It has been discovered that rust is generated more than expected in the portion corresponding to 6 and the portion covered with the mortar material 13, and deterioration of the anchor bolt 3 is a problem.

  Therefore, the applicant of the present invention, as an appropriate countermeasure to solve such a problem, the portion embedded in the foundation concrete 2 of the anchor bolt 3 is not exposed to the outside air and rust is not generated. In view of the above, a method for repairing a foundation for a structure that effectively utilizes this portion has been proposed (see Japanese Patent Application No. 2002-350365 specification and drawings).

  In one specific repair method of this proposal, first, as shown in FIG. 8, a hollow hole 20 is excavated so that a part of the embedded portion of the anchor bolt 3 is exposed around the anchor bolt 3 of the foundation concrete 2. The threaded portion 3a of the anchor bolt 3 is cut before or after. Subsequently, a new screw portion 21 (see FIG. 9) is formed at a portion exposed in the hollow hole 20 of the anchor bolt 3. Next, as shown in FIG. 9, a screw portion 22a is formed at one end, and a screw hole 22b that can be screwed into a new screw portion 21 of the anchor bolt 3 exposed in the hollow hole 20 at the other end. A rod-shaped connecting bracket 22 is prepared, and a screw hole 22 b of the connecting bracket 22 is screwed and fastened to a new threaded portion 21 of the anchor bolt 3. After that, the resin adhesive 23 is injected into the hollow hole 20 until the end of the connecting hole 22 on the screw hole 22b side is buried, and the sealing material is formed around each bolt hole 6 on the lower surface of the base plate 5 of the columnar structure 4. 24, and the base plate 5 is placed on the upper surface of the foundation concrete 2 with the sealing material 24 and the liner material 25 interposed between the bolt holes 6 of the base plate 5 of the columnar structure 4 and the threaded portions 22a of the connecting fittings 22. Place. Subsequently, after injecting a soft resin material 26 into a gap between the bolt hole 6 of the base plate 5 and the connection fitting 22, a nut 27 is screwed and fastened to the screw portion 22 a of the connection fitting 22 from above the base plate 5. Finally, the mortar material 28 is poured and solidified so as to cover the gap between the upper surface of the foundation concrete 2 and the base plate 5, particularly the periphery of the base plate 5.

  By the way, as a drilling method for drilling the hollow hole 20 so that a part of the embedded portion of the anchor bolt 3 is exposed around the anchor bolt 3 of the foundation concrete 2, a bottomed cylindrical core bit is attached to the tip of the electric drill. However, it is not easy to accurately and quickly excavate the anchor bolt 3 and the substantially concentric hollow hole 20 on the narrow foundation concrete 2 on the shoulder side of the rail 1. In particular, when the hollow hole 20 is excavated around the anchor bolt 3 located near the rail 1 of the foundation concrete 2, the anchor bolt 3 is very close to the rail 1 and the sound insulation wall 10 on the rail 1 is inspected. Since there are projections 14 such as eaves protruding outside, that is, closer to the columnar structure 4 near the mouth 11, the core bit of the core drill is inclined obliquely from the vertical direction with respect to the upper surface of the foundation concrete 2. There is a problem that excavation must be performed, and the excavation position is not easily determined due to the reaction of the core bit in the initial excavation.

  The present invention has been made in view of the above points, and the problem is that when a hollow hole is excavated around an anchor bolt using a core drill as described above, the excavation work is easily and reliably performed. Therefore, an excavation method and a hole excavation jig that can contribute to the practical application of the structural foundation repair method according to the prior application are provided.

  In order to solve the above-mentioned problem, the invention according to claim 1 is configured so that a part of the embedded portion of the anchor bolt is exposed around the anchor bolt embedded in the foundation concrete with the screw portion side protruding upward. As a drilling method for excavating the hollow hole, a rotatable body is provided at the protruding portion on the threaded side of the anchor bolt, and a core drill is prepared by attaching a bottomed cylindrical core bit to the tip of the electric drill, The core bit of the core drill is fitted on the rotating body with play and the core bit is positioned by the rotating body, and a cylindrical hole is drilled by the core drill. After that, the inner side of the cylindrical hole is crushed and empty. The cavern will be excavated.

  In this configuration, when drilling a cylindrical hole around the anchor bolt using a core drill, the core bit of the core drill has play in a rotating body provided in advance so as to be rotatable in the protruding portion on the threaded side of the anchor bolt. When fitted, the core bit is positioned by the rotating body. At that time, when the rotating body and the core bit come into contact with each other, the rotating body rotates as the core bit rotates, so that the rotation of the core bit and hence the drilling of the cylindrical hole are not affected by the contact, and the cylindrical hole can be easily drilled. This can be done reliably and reliably.

  According to a second aspect of the present invention, in the excavation method according to the first aspect, particularly when the hollow hole is excavated from obliquely above the upper surface of the foundation concrete, the protruding portion on the screw portion side of the anchor bolt is predetermined before the excavation. It cut | disconnects leaving the remainder part of height, and it is set as the structure which provides the said rotary body rotatably with respect to the remainder part. In this configuration, even when a cylindrical hole is excavated by tilting the core bit of the core drill, the protruding part on the threaded side of the anchor bolt does not interfere with excavation, and the cylindrical hole is inclined by the guide function of the rotating body. It can be easily and reliably excavated in the direction.

  The invention according to claim 3 is the excavation method according to claim 2, in particular, as a hole excavation jig used when excavating a cylindrical hole from an oblique upper side of the upper surface of the foundation concrete using the core bit of the core drill. A columnar jig body and a ring-shaped rotating body rotatably mounted on the upper outer peripheral surface of the jig body are provided. Then, the jig body is formed such that the lower surface thereof is inclined at a predetermined angle with a plane perpendicular to the central axis, and a fitting hole for fitting the remaining portion of the anchor bolt is orthogonal to the lower surface of the jig body. A plurality of tap holes extending toward the fitting hole are formed on the outer peripheral surface of the jig body.

  In this configuration, when drilling a cylindrical hole using a hole drilling jig, first, the fitting hole of the jig body is fitted to the remaining part of the anchor bolt, and the jig body is placed on the foundation concrete. At the same time, by screwing the tap into each tap hole of the jig body from the outer peripheral surface side, the jig body is in a predetermined state with respect to the remaining portion of the anchor bolt, that is, the center axis of the jig body is inclined by a predetermined angle from the vertical direction Fix to the state. After that, the core bit of the core drill is externally fitted to the rotating body mounted on the upper outer peripheral surface of the jig body so as to have a play, and the core bit is positioned by the rotating body and the cylindrical hole is drilled by the core drill. Thus, the drilling operation of the cylindrical hole can be performed easily and reliably in a state where the core bit of the core drill is inclined obliquely from the vertical direction with respect to the upper surface of the foundation concrete.

  According to a fourth aspect of the present invention, in the hole excavation jig according to the third aspect, a pressing plate for preventing the rotator from coming off is attached to the upper surface of the jig main body, and a handle is provided on the pressing plate. To do. In this configuration, the holding plate attached to the upper surface of the jig body has a function as an attachment member for providing a handle in addition to a function for preventing the rotating body from coming off, thereby reducing the number of parts. While reducing the jig body, the jig can be easily carried.

  As described above, according to the excavation method of the present invention, when a cylindrical hole or a hollow hole is excavated around the anchor bolt using the core drill, the core bit is removed by the rotatable rotating body provided at the protruding portion of the anchor bolt. Since the cylindrical hole can be excavated by the core drill while performing positioning, the excavation work can be easily and reliably performed, which can contribute to the practical use of the structural foundation repair method according to the prior application. . In particular, in the invention according to claim 2, even when excavating the cylindrical hole by tilting the core bit of the core drill obliquely, the protruding portion on the screw portion side of the anchor bolt does not obstruct the excavation, and the excavation work is easy. Speedup can be effectively achieved.

  Moreover, according to the hole excavation jig of the present invention, when excavating a cylindrical hole from the diagonally upper surface of the foundation concrete using the core bit of the core drill, the excavation work can be easily and reliably performed. This can further contribute to the practical application of the structural foundation repair method according to the prior application. In particular, the invention according to claim 4 is advantageous for implementation because the hole excavation jig can be easily carried while reducing the number of parts.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments that are the best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 shows a state of one step of an embodiment in which the excavation method of the present invention is applied when excavating a hollow hole around an anchor bolt 3 located near a rail 1 of a foundation concrete 2. In FIG. 1, 30 is a core drill, and this core drill 30 is known as a hand-type drilling tool. A core bit 32 having a bottomed cylindrical shape is attached to the tip of an electric drill 31, and the core bit 32 is shown in FIG. Although not shown, it has a blade portion made of diamond or the like at the tip.

  Reference numeral 40 denotes a hole excavation jig used when excavating a cylindrical hole in a state where the core bit 32 of the core drill 30 is inclined obliquely from the vertical direction with respect to the upper surface of the foundation concrete 2. 2 and 3, a substantially cylindrical jig body 41, a ring-shaped rotating body 42 rotatably mounted on the upper outer peripheral surface of the jig body 41, and a jig body 41. And a U-shaped handle 45 fixed to the pressing plate 44 by welding. The circular pressing plate 44 is fixedly attached to the upper surface of the rotating body 42 with fastening bolts 43 to prevent the rotating body 42 from coming off. .

  The lower surface of the jig body 41 is inclined with respect to a plane perpendicular to the central axis by a predetermined angle (about 10 ° to 20 °). A fitting hole 46 that can be fitted to the anchor bolt 3 is formed in a direction orthogonal to the lower surface at the position where the anchor bolt 3 is fitted, and three taps extending toward the fitting hole 46 are formed on the lower outer peripheral surface of the jig body 41. Holes (screw holes) 47, 47, 47 are formed at substantially equal intervals in the circumferential direction. Further, the upper outer peripheral surface of the jig body 41 is formed to have a smaller diameter than the lower outer peripheral surface, and the rotating body 42 is sandwiched between the stepped portion of the boundary and the pressing plate 44 so that the rotating body 42 is located above the jig main body 41. It is rotatably provided on the outer peripheral surface. The outer diameter of the rotating body 42 is set smaller than the inner diameter of the core bit 32 by a predetermined dimension (about 1 to 3 mm).

  Next, an operation procedure, that is, an excavation method when excavating a hollow hole around the anchor bolt 3 located near the rail 1 of the basic concrete 2 using the core drill 30 and the hole excavation jig 40 will be described.

  First, after the columnar structure 4 as shown in FIGS. 5 to 7 is removed from the foundation concrete 2, the four anchor bolts 3, 3... Embedded in the foundation concrete 2 are above the upper surface of the foundation concrete 2. Each protruding portion on the protruding screw portion 3a side is cut. At that time, the anchor bolt 3 located near the rail 1 of the foundation concrete 2 has a predetermined height (about 20 to 30 mm) corresponding to the fitting hole 46 of the jig body 41 of the hole excavation jig 40. The remaining portion 3b (see FIG. 1) is left and cut.

  Subsequently, the fitting hole 46 of the jig body 41 is fitted into the remaining portion 3 b of the anchor bolt 3, and the hole excavation jig 40 is placed on the foundation concrete 2. At that time, the jig 40 is placed in a state where the central axis of the jig body 41 is inclined from the vertical direction (vertical direction) to the side away from the rail 1. In this state, the tap (or set screw) 48 is screwed into the three tap holes 47, 47, 47 of the jig main body 41 from the outer peripheral surface side and pressed against the anchor bolt 3 in the fitting hole 46, so The tool main body 41 and the hole excavation jig 40 are fixed to the remaining portion 3 b of the anchor bolt 3.

  After that, as shown in FIG. 1, the core drill 30 is externally fitted to the rotating body 42 of the hole excavating jig 40 with play and the core bit 32 is positioned by the rotating body 42 while positioning the core bit 32. Thus, a cylindrical hole is excavated obliquely around the anchor bolt 3 as a substantial center. At this time, the jig body 41 and the center axis of the hole excavation jig 40 are inclined to the side away from the rail 1 from the vertical direction, and the core bit 32 is fitted on the rotating body 42 of the hole excavation jig 40. Since the core drill 30 to be inclined is also inclined to the side away from the rail 1, the core drill 30 does not come into contact with the protruding portion 14 protruding outward from the rail 1 and the rail 1 side. Further, when the rotating body 42 and the core bit 32 come into contact with each other, the rotating body 42 rotates following the rotation of the core bit 32, so that the rotation of the core bit 32 and the excavation of the cylindrical hole are not affected by the contact. Moreover, even when a reaction occurs in the core bit 32 at the beginning of excavation, the excavation position of the core bit 32 does not shift, and a cylindrical hole can be excavated around the anchor bolt 3 easily and reliably.

  Subsequently, after removing the hole excavating jig 40 from the remaining portion 3b of the anchor bolt 3, the inside of the cylindrical hole is crushed with an air hammer or the like to excavate the hollow hole. As described above, the excavation work for the hollow hole for one anchor bolt 3 located near the rail 1 of the foundation concrete 2 is completed.

  Thus, in the excavation method of excavating the cylindrical hole and the hollow hole around the anchor bolt 3 using the core drill 30 and the hole excavation jig 40, the excavation work can be easily and reliably performed. This can contribute to the practical application of the structural foundation repair method according to the prior application.

  In addition, the hole excavation jig 40 functions as a mounting member for providing a handle 45 and a function for preventing the rotating body 42 from being detached from the holding plate 44 mounted on the upper surface of the jig body 41. Since it is combined with the function, the jig 40 can be easily carried while reducing the number of parts, which is advantageous for implementation.

  FIG. 4 shows a rotating body 50 used when excavating a cylindrical hole around an anchor bolt 3 located on a side away from the rail 1 of the foundation concrete 2. The rotating body 50 has a cylindrical shape with a relatively large thickness, and its inner diameter is set slightly larger (about 1 to 2 mm) than the outer diameter of the anchor bolt 3, and the outer diameter is the inner diameter of the core bit 32. Is set smaller than a predetermined dimension (about 1 to 3 mm).

  Next, the working procedure in the case of excavating a hollow hole around the anchor bolt 3 located on the side away from the rail 1 of the foundation concrete 2 using the rotating body 50 and the core drill 30 will be described. In the same manner as when excavating a hollow hole around the anchor bolt 3 located near the rail 1 of the foundation concrete 2, the remaining portion 3b having a predetermined height is cut when the protruding portion of the anchor bolt 3 on the threaded portion 3a side is cut. Cut leaving. However, the height dimension of the remaining portion 3 b may be larger than the height dimension of the rotating body 50 as long as it does not interfere with the drilling of the core drill 30. Further, if the length of the protruding portion of the anchor bolt 3 on the screw portion 3a side does not disturb the drilling of the core drill 30, the cutting of the screw portion 3a may be omitted.

  Subsequently, the rotary body 50 is fitted on the remaining portion 3b of the anchor bolt 3 (the screw portion 3a when cutting of the screw portion 3a is omitted) with play, that is, rotatably, and the core drill 30 is attached to the rotary body 50. The core drill 32 is externally fitted with play and the core drill 30 is set substantially perpendicular to the upper surface of the foundation concrete 2, and the core hole 30 is positioned substantially vertically by the core drill 30 while positioning the core bit 30 by the rotating body 50. Excavate. Thereafter, the rotating body 50 is removed and the inside of the cylindrical hole is crushed to excavate the hollow hole.

  Also in such excavation method, the cylindrical hole can be excavated by the core drill 30 while positioning the core bit 30 by the rotating body 50 externally fitted to the anchor bolt 3, so that the cylindrical hole and the hollow hole can be excavated. Can be easily and reliably performed.

  In addition, this invention is not limited to the said embodiment, A various other form is included. For example, in the above embodiment, as the hole excavation jig 40, a function for preventing the rotating body 42 from being detached from the holding plate 44 attached to the upper surface of the jig main body 41 and an attachment for providing the handle 45. The hole excavation jig of the present invention is not limited to this, but an annular groove is formed on the outer peripheral surface of the jig body 41, and a ring-shaped rotation is formed in the annular groove. The presser plate may be omitted by fitting the body rotatably. Further, the handle may be directly attached to the jig body.

It is sectional drawing which shows 1 process of the excavation method which concerns on embodiment of this invention. It is a vertical side view of the hole excavation jig according to the embodiment of the present invention. It is sectional drawing in the XX line of FIG. (A) is a top view of a rotary body, (b) is sectional drawing in the YY line of (a). It is sectional drawing which shows the installation structure of columnar structures, such as an illumination pillar. It is the figure which expanded the principal part of FIG. It is sectional drawing in the ZZ line | wire of FIG. It is sectional drawing which shows the state in the middle of the repair for demonstrating the repair method of the foundation for structures concerning a prior application. It is sectional drawing which similarly shows the state after repair.

Explanation of symbols

2 foundation concrete 3 anchor bolt 3a screw part 3b remaining part 4 columnar structure 20 hollow hole 30 core drill 31 electric drill 32 core bit 40 hole excavation jig 41 jig body 42, 50 rotating body 44 holding plate 45 handle 46 fitting hole 47 Tap hole

Claims (4)

An excavation method for excavating a hollow hole so that a part of the embedded portion of the anchor bolt is exposed around the anchor bolt embedded in a state in which the screw portion side protrudes upward in the foundation concrete,
A rotatable body is provided at the protruding portion of the anchor bolt on the threaded side, and a core drill is prepared by attaching a bottomed cylindrical core bit to the tip of the electric drill, and the core bit of the core drill is attached to the rotating body. A cylindrical hole is excavated by a core drill while positioning the core bit with a rotating body while being fitted with play, and then a hollow hole is excavated by crushing the inside of the cylindrical hole. Drilling method.   When excavating the hollow hole obliquely from above the upper surface of the foundation concrete, the projecting portion on the threaded side of the anchor bolt is cut leaving a residual portion of a predetermined height prior to the excavation, and the rotating body against the residual portion The excavation method according to claim 1, wherein the excavator is rotatably provided. In the excavation method according to claim 2, in particular, a hole excavation jig used when excavating a cylindrical hole obliquely above the upper surface of the foundation concrete using the core bit of the core drill,
The jig body includes a substantially cylindrical jig body and a ring-shaped rotating body rotatably mounted on the upper outer peripheral surface of the jig body, and the jig body has a plane whose lower surface is orthogonal to the central axis. The lower surface of the jig body is formed with a fitting hole that fits in the remaining portion of the anchor bolt in a direction perpendicular to the lower surface, and on the lower outer peripheral surface of the jig body. A hole excavation jig characterized in that a plurality of tap holes extending toward the fitting hole are formed. 4. The hole excavation jig according to claim 3, wherein a pressing plate for preventing the rotating body from coming off is attached to the upper surface of the jig main body, and a handle is provided on the pressing plate.

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