JP5773516B2 - Repair and reinforcement methods for existing concrete structures - Google Patents

Description

  The present invention relates to a method for repairing and reinforcing an existing concrete structure. More specifically, the present invention relates to a technique for cutting a concrete wall surface (for example, an inner wall surface of a hole drilled in a concrete floor board), a ground, or the like.

As a foundation for receiving the weight of the superstructure or the like on a horizontal plane, it has been conventionally practiced to place a concrete floor board on the ground surface subjected to the ground treatment.
For example, in a power transmission tower constructed in the Showa 40s, there is a floorboard made of concrete and having a thickness of about 2 m to 2.5 m as a foundation.
Such concrete floorboards are constructed with the expectation of shear strength only for concrete.

In such a floor board, peeling or cracking may occur in the floor board due to a so-called “cold joint” or the like. And there exists a concern that the shear strength in a floor board may fall by such peeling or a crack.
In addition, when the superstructure of the floorboard is a track or a road and heavy objects such as railways and vehicles frequently come and go, the foundation concrete part or the lower part of the floorboard is Furthermore, there is a risk that the ground below will soften. And if a foundation concrete part and also the ground under it soften, there exists a possibility that a floor board may sink by the weight of the upper part.

For the problem of lowering the shear strength in the floor board due to the above-mentioned peeling or cracking, in order to reinforce the floor board, a reinforcing bar extending in the vertical direction of the floor board is arranged in the region including the peeling or cracking, The construction which reinforces the part which peeled or cracked mentioned above by making the said reinforcing bar act as an anchor member is generally performed.
In such reinforcement work, a reinforcing bar insertion hole (for example, φ53 mm to 65 mm) for arranging a reinforcing bar is drilled at a predetermined position on the floor board by a core drill having a diamond tip, for example.
Then, a reinforcing bar is inserted into the drilled reinforcing bar insertion hole and filled with non-shrink mortar.

Here, when a core drill having a diamond tip is used, the inner wall surface of the reinforcing bar insertion hole drilled in the floor plate becomes too smooth.
Therefore, after the filled mortar is cured, if the pulling force is applied to the rebar placed on the ground side, the frictional resistance on the inner wall of the rebar insertion hole is small, so the rebar is pulled out of the rebar insertion hole together with the hardened mortar. There is a risk that.

In order to prevent the situation where the reinforcing bar comes out of the reinforcing bar insertion hole together with the mortar, a recess is formed on the inner wall surface of the reinforcing bar insertion hole (so-called “scratch”) or a groove is formed (so-called “graining”). Is conventionally performed.
If a recess is formed on the inner wall surface of the reinforcing bar insertion hole or a groove is formed, even if a force that pulls the reinforcing bar toward the ground acts, the mortar that has entered the recess or the groove exerts a resistance force. is there.

As a technique for performing such “roughening”, for example, a cutting device having an outer diameter substantially equal to the inner diameter of the reinforcing bar insertion hole and having a plurality of carbide tips protruding on the outer peripheral surface is inserted. A technique has been proposed in which a hole is inserted while rotating from the ground side, thereby forming a spiral groove on the inner wall surface of the reinforcing bar insertion hole.
However, in such a technique, since a cutting device having an outer diameter substantially equal to the inner diameter of the reinforcing bar insertion hole is inserted while rotating from the ground side, a large torque is required for the cutting device, etc. There are problems such as an increase in product cost and an increase in construction cost.

As a solution to the above problem, there is a conventional technique (see Patent Document 1) that uses a roller bit attached to a piston rod of a fluid pressure piston that is relatively disposed along the radial direction of the reinforcing bar insertion hole as a roughening means. .
The related art (Patent Document 1) has an advantage that the groove width and groove depth of the annular groove can be arbitrarily adjusted, but requires fluid and piping for operating the roughening means, and the configuration is complicated. Therefore, it is hard to say that the company is fully responding to the need to control high costs.

In addition, for the problem of subsidence of the floor board due to the softening of the foundation concrete part or the ground below, the floor board part is drilled with a core drill or the like, the ground under the floor board is drilled to the support layer, After inserting the core material, it was filled with mortar and the like, and piles were laid, thereby enhancing the ground supporting force.
According to such a construction method, the weight and impact from the upper portion of the floor board are supported by the force of the core material and the filler adhering to the inner wall of the hole. However, as described above, since the inner wall surface of the hole drilled with a core drill or the like is smooth, it is difficult to increase the force with which the filler adheres to the inner wall of the drilling hole, and supports a large weight and impact. Is difficult.

JP 2008-105339 A

The present invention has been proposed in view of the above-described problems of the prior art, and does not require fluid pressure and does not require a complicated configuration and equipment. The chip is less likely to break and is drilled in a concrete floor board. In addition, a cutting device that can perform roughing work with the same device even if there are multiple types of inner diameters of the reinforcing bar insertion holes can enhance the weight and impact support from the top of the floorboard. The purpose is to repair and reinforce concrete structures.

According to the present invention, a drilling hole (H) is drilled in a concrete layer (S), an inner wall surface of the concrete hole (H) is cut to form a recess, a reinforcing bar is inserted, and mortar is filled. In a method for reinforcing and repairing a concrete structure, a rod (Rd) to which a rotational force is applied by a rotational drive source provided on the ground side, and a shaft portion (connected to the underground side end of the rod (Rd) ( SH), a flat plate member (1) fixed to the shaft portion (SH), a bit (2) rotatably provided on the flat plate member (1), and a tip of the bit (2) . A cutting device (10) provided with a tip (3) and a stopper (5) provided on the flat plate member (1) so that the bit (2) does not rotate excessively is prepared, and the bit (2) , when said rod (Rd) is not rotating is located radially inwardly, Serial rods when (Rd) is rotating at least 300rpm is rotated about the rotational axis (4), above end provided with said chip (3) is positioned radially concrete layer Drill the boring hole (H) to the area (C, G) below (S), place the cutting device (10) in the boring hole (H), and move the rod (Rd) at 300 rpm to 1000 rpm. The diameter of the bit (2) is increased by rotating, and the tip (3) provided at the tip of the bit (2) is made to collide with the inner wall surface of the concrete layer (S) to cause the inner wall surface of the borehole to rotate. When the chip (3) hits the inner wall surface of the boring hole (H), the bit (2) provided with the chip (3) returns to the inner side in the radial direction, and the concrete of the boring hole (H) is formed. Area below layer (S) In C, G), the rod (Rd) is rotated at the same location for an arbitrary time, and the tip (3) at the tip of the bit (2) is made to collide with the inner wall surface of the boring hole (H). ) Is enlarged.

According to the present invention having the above-described configuration, when the cutting device (10) rotates, the bit (2) provided with the tip (3) at the tip is expanded from the cutting device (10) by centrifugal force. . When the tip (3) at the tip of the bit hits the inner wall surface of the reinforcing bar insertion hole (H), a recess (so-called “scratch”) is formed on the inner wall surface of the reinforcing bar insertion hole (H). At the same time, when the tip (3) hits the inner wall surface of the reinforcing bar insertion hole (H), the bit (2) provided with the tip (3) returns radially inward (in the direction of diameter reduction).
Then, the bit (2) expands again due to centrifugal force, the tip (3) collides with the inner wall surface of the reinforcing bar insertion hole (H), and a recess is formed on the inner wall surface of the reinforcing bar insertion hole (H). The diameter is immediately reduced radially inward.
By repeating this, a recess is formed on the inner wall surface of the inner wall surface of the reinforcing bar insertion hole (H). Here, if the vertical position of the bit (2) is the same, an annular groove is formed on the inner wall surface of the reinforcing bar insertion hole (H). According to the present invention, so-called “grain roughening” is performed in this way.
In addition, since the tip (3) collides with the inner diameter of the reinforcing bar insertion hole (H) and a recess is formed on the inner wall surface, the reinforcing bar (30) is placed and filled with mortar (non-shrinking mortar 40). Even if the reinforcing bar (30) is pulled by the shear resistance of the mortar (40) that has entered the recess, the mortar (40) and the reinforcing bar (30) are prevented from coming out of the reinforcing bar insertion hole (H). The

Further, according to the present invention, even when the outer diameter of the cutting device (10) is not equal to the inner diameter of the reinforcing bar insertion hole (H), the cutting device (10) can be inserted into the reinforcing bar insertion hole (H). For example, by rotating the cutting device (10) at a predetermined rotational speed (300 rpm) or more and expanding the diameter of the bit (2) from the cutting device (10) by the centrifugal force, the inner wall of the reinforcing bar insertion hole (H) is formed. The chip (3) can be collided to perform the “graining” operation.
That is, according to the present invention, as long as the cutting device (10) can be inserted into the reinforcing bar insertion hole (H), the inner diameter dimension of the reinforcing bar insertion hole (H) is not limited to the inner diameter of the reinforcing bar insertion hole (H). “Roughening” can be applied to the inner wall surface. In other words, even if there are a plurality of types of inner diameter dimensions of the reinforcing bar insertion hole (H), it is possible to perform the “roughening” operation with a single cutting device (10).

In the present invention, in the region below the concrete layer (for example, floor board S) (for example, foundation concrete C below the floor board, softened ground Gn, ground G, support layer Gs), the inner diameter of the boring hole (insertion hole H) is If it is configured to expand, in the boring hole (insertion hole H), the area where the inner diameter is expanded in the area (C, G, Gn, Gs) below the concrete plate (for example, floor board S) A stepped portion is formed at the boundary with (H2).
If a core material (for example, steel pipe 30A) is inserted into the boring hole (reinforcing bar insertion hole H), mortar (40) is filled, and the mortar (40) is cured to form a pile, The concrete layer (S) can be prevented from sinking by supporting the weight of the layer (S) and the superstructure (railway, road, train, large automobile, etc.).

It is a front view showing the state where the diameter of the cutting device concerning a 1st embodiment of the present invention was expanded. It is a top view of the cutting device of the state shown in FIG. It is a front view which shows the state which the cutting device which concerns on 1st Embodiment reduced in diameter. It is a top view of the cutting device of the state shown in FIG. It is sectional drawing which shows the process of arrange | positioning the cutting device reduced in diameter in the reinforcing bar insertion hole. It is sectional drawing which shows the state which rotated the cutting device and expanded the bit diameter in the state shown in FIG. It is sectional drawing which shows the state immediately after the chip | tip of a bit front-end | tip collided with the inner wall surface of the reinforcing bar insertion hole. It is a top view which shows the state of FIG. 6 in detail. It is a top view which shows the state in which the recessed part was formed in the rebar insertion hole inner wall surface. It is sectional drawing for demonstrating the construction area | region where 2nd Embodiment of this invention is applied. It is sectional drawing which shows the process of drilling an insertion hole in the construction area | region shown in FIG. It is sectional drawing which shows the process of expanding the area below a floor board in 2nd Embodiment. It is sectional drawing which shows the state which inserted the core material into the insertion hole by which the area | region below the floor board was expanded in diameter. It is sectional drawing which shows the state by which the pile was created in 2nd Embodiment. It is a front view which shows the cutting device which concerns on 3rd Embodiment of this invention. It is a front view which shows the state which the cutting device which concerns on 4th Embodiment reduced in diameter. It is a top view of the cutting device of the state shown in FIG. It is a front view which shows the state which the cutting apparatus which concerns on 4th Embodiment expanded. It is a top view of the cutting device of the state shown in FIG.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, a first embodiment of the present invention will be described with reference to FIGS.
1 to 4 show a cutting apparatus (reference numeral 10 is attached to the entire apparatus) according to a first embodiment of the present invention.
1 and 2 show a state in which the bit 2 of the cutting device 10 according to the first embodiment has expanded (expanded) radially outward. 3 and 4 show a stowed state (a reduced diameter state) in which the bit 2 of the cutting device 10 according to the first embodiment has moved inward in the radial direction.

1 to 4, in the cutting device 10, the shaft portion SH and the bearing portion 1 are integrally manufactured. For example, it can be manufactured by fixing a pair of bearing portions 1 and 1 to a shaft portion SH connected to the underground side end portion (the lower end portion in FIGS. 1 and 3) of the cylindrical rod Rd by welding or the like. . Alternatively, for example, the upper and lower portions of a cylindrical shaft portion SH having a diameter of 200 mm can be cut to about 65 mm, and the bearing portion 1 that functions as a bearing for the bit 2 can be formed in the middle portion.
1 to 4, the bit 2 is rotatably arranged with respect to each of the bearing portions 1. The inner side of the bit 2 in the radial direction is separated into two upper and lower portions 2A and 2B, and the bearing portion 1 is inserted in a region between the upper member 2A and the lower member 2B. In other words, the upper member 2A and the lower member 2B on the inner side in the radial direction of the bit 2 sandwich the bearing portion 1 in the vertical direction Y (the vertical direction in FIGS. 1 and 3).
The vertical gap between the upper member 2A and the lower member 2B on the inner side in the radial direction of the bit 2 is set slightly larger than the thickness of the bearing portion 1 (vertical dimension: Y dimension).

2 and 4, the bearing portion 1 is formed by cutting a part of a columnar shape, and the bit 2 is accommodated in the notched region. Depending on the shape of the bit 2, it may be unnecessary to form a notched region.
Rotating shafts (hereinafter referred to as “bit rotating shafts”) 4 are inserted into the bearing portion 1 of the cutting apparatus 10 at positions that are point-symmetric about the axis O of the bearing portion 1.
As shown in FIGS. 1 and 3, the bit rotation shaft 4 passes through the upper member 2 </ b> A and the lower member 2 </ b> B of the bit 2 and the bearing portion 1. In other words, two through holes are formed through the upper member 2A, the lower member 2B, and the bearing portion 1 of the bit 2, and the bit rotating shaft 4 is inserted into the through hole.
As described above, the upper member 2A and the lower member 2B on the inner side in the radial direction of the bit 2 sandwich the bearing portion 1 in the vertical direction Y (the vertical direction in FIGS. 1 and 3), and the upper member 2A of the bit 2 Since the bit rotating shaft 4 is inserted through the lower member 2B and the bearing portion 1, the bit 2 can rotate (rotate) with respect to the bearing portion 1 around the bit rotating shaft 4. is there.

As shown in FIG. 2, the bit 2 has a substantially rectangular planar shape, and a cutting tip 3 is attached to a corner portion on the radially outer side. The cutting tip 3 has a shape suitable for cutting an inner wall surface of a hole to be described later, has a sharp tip, and is manufactured from a hard material. As can be seen from FIG. 2, the cutting tip 3 radially outward of the right bit 2 in FIG. 1 cannot be directly seen in the arrangement of FIG. Therefore, in the bit 2 on the right side of FIG. 1, the cutting tip 3 is indicated by a dotted line.
A through-hole is drilled at a position corresponding to the through-hole of the bearing portion 1 in the rear portion (inward in the radial direction) of the bit 2 so as to be rotatable about the bit rotation shaft 4.
Although not shown in FIGS. 1 and 3, the upper portion of the cutting device 10 is threaded so that it can be connected to the upper structure such as the rod Rd or the upper guide member 6 (see the third embodiment in FIG. 15). Has been. The lower part of the cutting device 10 is threaded so as to be connectable to the lower guide member 7 (see the third embodiment in FIG. 15).
When a rotational force is applied to the rod Rd by a rotation drive source (not shown) provided on the ground side, the cutting device 10 connected to the rod Rd also rotates. For example, when rotating at a rotational speed of 300 rpm or more in the direction of arrow RO (rotational direction), the bit 2 is in a state of maximum diameter expansion as shown in FIG.

As shown in FIGS. 2, 4, 8, and 9, when the bit 2 rotates in the rotation direction RO at a rotation speed of 300 rpm or more and expands in diameter, the bit 2 rotates too much in the rotation direction. In order to regulate this, it is possible to provide a stopper pin 5.
In the example of FIG. 2, the stopper pin 5 is in contact with the traveling direction side edge 2sf in a state where the bit 2 is rotated at a rotational speed of 300 rpm or more in the rotational direction RO and has the maximum diameter expanded, and the bit 2 is further arrowed. It is regulated not to move to the RO side.
As will be described later, since the diameter of the bit 2 is increased by centrifugal force, the bit 2 does not move to the arrow RO side (normally) beyond the state shown in FIG. 2 even if the stopper pin 5 is not provided. .
Further, by adjusting the position of the stopper pin 5, it is possible to adjust the diameter at which the ground can be cut when the bit 2 is expanded.
Although not shown, for example, the position of the stopper pin 5 in FIG. 2 is set to a position where the amount of diameter expansion of the bit 2 is suppressed (the stopper pin 5 of the right bearing portion 1 in FIG. The amount of the bit 2 that can be expanded to the maximum can be controlled by displacing the stopper pin 5 in the upper left direction).
In other words, by adjusting the position of the stopper pin 5, it is possible to arbitrarily set the depth of the groove when cutting an annular groove in the ground as will be described later.

The state in which the diameter of the bit 2 is reduced (the state in which the bit 2 is accommodated: at the time of non-cutting) is shown in FIGS.
In order to expand the diameter of the diameter-reduced bit 2 (FIGS. 3 and 4) (FIGS. 1 and 2), the rod Rd and the cutting device 10 are rotated at a rotational speed of 300 rpm to 1000 rpm.

Although not shown, for example, in FIG. 1, if the tips 3 provided at the tips of the left and right bits 2 are arranged so that their vertical positions (positions in the Y direction in FIG. 1) are different, the diameter of the bits 2 is increased during excavation. Then, when the tip 3 collides with the inner wall surface of the reinforcing bar insertion hole H, the recesses are simultaneously formed at two different positions in the vertical direction, so that the “roughening” efficiency is improved.
On the other hand, if the vertical position of the tip of the left chip 3 is the same as the vertical position of the tip of the right chip 3 (see, for example, FIG. 1), an annular groove can be quickly formed on the inner wall surface of the reinforcing bar insertion hole. Can be formed.

After finishing the roughening operation, the cutting device 10 is pulled out to the ground side.
At that time, if necessary, the rod Rd is rotated in the direction of the arrow RS to reduce the diameter of the expanded bit 2 as shown in FIGS. 3 and 4 and pull it up to the ground side.
Although not clearly shown, it is configured such that water or compressed air is jetted from the lower end of the cutting device 10 toward the underground side, and the cut concrete chips and slime are discharged to the ground side. I can do it.

Next, with reference to FIG. 5 to FIG. 9, an aspect of “roughening” according to the first embodiment will be described.
In the process shown in FIG. 5, the cutting device 10 connected to the lower end (the end on the ground side) of the rod Rd is inserted into the reinforcing bar insertion hole H drilled in the floor plate S with a diamond bit (not shown).
In the state shown in FIG. 5, the cutting device 10 is in a reduced diameter state shown in FIGS. 3 and 4. That is, the bit 2 is housed in the bearing portion 1 and is not open.

In the process shown in FIG. 6, the rod Rd and the cutting device 10 are rotated from the state of FIG. 5 in the direction of the arrow RO (the turning direction in which the diameter of the bit 2 having a reduced diameter is increased).
When the rotation exceeds a predetermined rotation, the bit 2 is opened (expanded) by centrifugal force, and the tip 3 at the tip collides with the inner wall surface of the reinforcing bar insertion hole H. The locations where the tip 3 collides with the inner wall surface of the reinforcing bar insertion hole H are indicated by the signs P1 (right side in FIG. 6) and P2 (left side in FIG. 6) in FIG.
As a result, two concave portions (so-called “scratches”) P1 and P2 are formed at positions where the chip 3 collides with the inner wall surface of the reinforcing bar insertion hole H.

When the tip 3 at the tip collides with the inner wall surface of the reinforcing bar insertion hole H to form two recesses P1 and P2 (FIG. 6), the bit 2 is once moved radially inward by the reaction of the collision. Although it moves (moves in the direction of diameter reduction) (FIG. 7), since the rotational force is continuously given to the cutting device 10, the bit 2 is opened again by the centrifugal force.
Hereinafter, the state shown in FIG. 6 and the state shown in FIG. 7 are repeated, and innumerable recesses are formed on the inner wall surface of the reinforcing bar insertion hole H.
8 to 9 show the above-described recess formation in a plan view.

8 and 9, a rotational force in a rotational RO direction (a direction in which the bit 2 expands in diameter) is applied to the cutting device 10 through the rod Rd by a rotational force from a rotational driving force source (not shown). Then, when the rotation exceeds a certain level, centrifugal force acts, and the bit 2 is rotated outwardly about the axis 4o of the rotating shaft 4 (the bit 2 opens and expands in diameter).
In the illustrated example, the bit 2 is configured to open (expand the diameter) counterclockwise (arrow RO direction), but the bit 2 is rotated when the rod Rd and the cutting device 10 are rotated in the reverse direction (clockwise). Of course, it is also possible to configure so as to open.
Then, the centrifugal force is increased by the continuous rotation of the cutting device 10, and the tip 3 at the distal end portion of the expanded bit 2 collides with and hits the inner wall surface of the reinforcing bar insertion hole H. A concave portion (so-called “scratch”) is formed on the inner wall surface at a location where the tip 3 collides with the inner wall surface of the reinforcing bar insertion hole H.

Here, if the vertical position (the vertical position in FIGS. 5 to 7) of the cutting device 10 is the same, the innumerable recesses are formed at the same vertical positions as the recesses P1 and P2 in FIG. Further, by repeating the above operation at the same position, the concave portion (scratch) created as a “point” on the inner wall surface of the reinforcing bar insertion hole H is an annular groove that is a continuous “line” or “surface”. Formed as. By further expanding and deepening the groove portion, the reinforcing bar insertion hole H is eventually expanded.
On the other hand, when the vertical position of the cutting device 10 is gradually changed, a large number of recesses are intermittently formed on the inner wall surface of the reinforcing bar insertion hole H.

Here, the rotation speed of the rod Rd and the cutting device 10 will be described.
After the tip 3 collides with the inner wall surface of the reinforcing bar insertion hole H, the bit 2 tries to close by using this as a reaction force (an attempt to return in the direction opposite to the arrow RO direction: the bit 2 in the direction of the arrow RI in FIG. 8). However, the bit 2 is pushed out again in the diameter-expanding direction by the centrifugal force generated by the continuous rotation of the cutting device 10 and collides with the inner wall surface of the reinforcing bar insertion hole H.
By the way, the higher the rotational speed of the rod Rd and the cutting device 10, the more the centrifugal force acting on the bit 2 increases, and the bit 2 receives the reaction force (returned in the direction opposite to the arrow RO direction: bit 2). Since the time until the rotation is again switched to the RO direction is shortened, the number of times that the bit 2 collides with the inner wall surface of the reinforcing bar insertion hole H increases. Moreover, since the speed at which the bit 2 expands becomes faster and the impact force that the tip 3 collides with the inner wall surface of the reinforcing bar insertion hole H becomes stronger, the depth of the concave portion on the inner wall surface of the reinforcing bar insertion hole H becomes sufficiently deeper. The time for forming the is reduced, and the efficiency of the “roughening” operation is improved.
On the other hand, when the rotational speed of the rod Rd and the cutting device 10 is less than 300 rpm, the time until the bit 2 is switched to the rotation in the RO direction again becomes long, and the speed of expanding the diameter also becomes slow. The number of times that 3 collides with the inner wall surface of the reinforcing bar insertion hole H and the impact force are insufficient. For this reason, a long time is required for forming the recess, and the efficiency of the “roughening” operation is lowered.

On the other hand, if the rotation speed of the rod Rd and the cutting device 10 is higher than 1000 rpm, the rotational force transmission system for applying rotation to the rod Rd and the cutting device 10 and the cutting device 10 main body may be damaged. is there.
Therefore, in the illustrated embodiment, the rotational speed of the bit is set to 1000 rpm or less.

Next, a second embodiment of the present invention will be described with reference to FIGS.
In the first embodiment, referring to FIG. 5 to FIG. 9, the “roughening” is performed on the inner wall surface of the reinforcing bar insertion hole H formed in the floor board S using the cutting device 10 shown in FIG. "Do the work.
On the other hand, in the second embodiment, for example, in a place where heavy objects such as railways and vehicles frequently come and go, the foundation concrete portion and the ground below it are softened by vibration and shock caused by the coming and going, and the floor board is As a measure to prevent the sinking, piles are placed.

In FIG. 10, the upper structure of the floor board S is a track and a road, and the ground G is softened by vibrations and impacts caused by a railroad T, a vehicle (for example, a large vehicle such as a bus or a truck) V, and the like. The softened ground is indicated by the symbol Gn), and the area where the floor board S may sink is shown.
In the example shown in FIG. 10, after excavating the ground G at the floor plate S placement position to a certain depth and placing the foundation concrete C, the floor plate S is constructed. In FIG. 10, a floor board S-shaped sleeper is indicated by reference numeral WR, and a rail for rails arranged on the sleeper WR is indicated by reference numeral Rl.
As a measure for preventing the floor board from sinking, it is known to place a support pile from the top of the floor board S. However, in the conventional measures, the pile expects the adhesive force between the floor board S and the pile as a force to support the floor board S, but the inner wall surface of the insertion hole H drilled in the floor board S is smooth as described above. Therefore, the adhesive force between the floor board S and the pile filler was insufficient.
In order to solve such a problem, in the second embodiment shown in FIGS. 10 to 14, a part of the pile is expanded in diameter, and a pile having a structure that handles the weight of the upper portion in the expanded part is placed.

In the second embodiment, as shown in FIG. 11, first, a hole communicating from the upper part of the floor board S to the ground G is drilled by the drilling machine BM. In order to make a support pile, the insertion hole H is drilled until it reaches the support layer GS.
Next, in the step shown in FIG. 12, the cutting device 10 connected to the tip of the rod Rd connected to a rotational driving force generation source (not shown) (the lower side in FIG. Set at the bottom (lower side of FIG. 12).
Then, as described above with reference to FIGS. 5 to 9, an annular groove is formed in the insertion hole H by continuously rotating the cutting device 10 at 300 rpm to 1000 rpm at the same vertical position. Thus, the diameter of the insertion hole H is expanded. After the lowermost portion has been able to sufficiently expand the diameter, the cutting device 10 is moved (pulled up) to the unexpanded portion on the ground side (upper side in FIG. 12) to increase the diameter of the unexpanded portion in the same manner. Do. In the example of FIGS. 12 to 14, the insertion hole H drilled at φ200 mm is expanded to φ300 mm.

In the process shown in FIG. 13, the diameter of the insertion hole H is increased to φ300 mm until reaching the lower portion of the floor board S, and then the cutting device 10 is pulled up to the ground side, and a pile core material (for example, steel pipe) 30A is inserted.
In FIG. 13, the casting thickness of the floor board S (vertical distance in FIG. 13) is 2 m, the casting thickness of the foundation concrete C (vertical distance in FIG. 13) is 1 m, and the length of the expanded portion Since the length (distance in the vertical direction in FIG. 13) is 1.5 m, the lowermost part (lower side in FIG. 13) of the enlarged diameter part reaches the ground G under the foundation concrete C. Here, each dimension (the casting thickness of the floor board S, the casting thickness of the foundation concrete C, the length of the enlarged diameter portion) is appropriately determined in consideration of the weight of the floor board S and the upper structure, the impact force, and the like. .

In the step shown in FIG. 14, the insertion hole H is filled with a filler (for example, mortar) 40 after the core material 30 </ b> A is inserted, the head processing 42 is performed, and the placement of the support pile 44 is completed.
As shown in FIG. 14, the support pile 44 that has been placed has a diameter increased from φ200 mm to φ300 mm at the lower part of the floor board S, so that the support force is increased by increasing the friction area. Further, since the step 44S is formed in the support pile 44, the step 44S sufficiently takes the weight and impact from the floor board S and the upper structure, and the support pile 44 main body is formed by the support layer Gs in the deep ground G. Since it is supported, it can prevent that the floor board S sinks.
Furthermore, if the inner wall surface HI of the insertion hole H drilled in the floor board S is “grained” as described above with reference to FIGS. 5 to 9, the filler 40 of the support pile 44 and the floor board S As a result, the floor plate S and the support pile 44 can be integrated. Moreover, when the area | region Gn in the ground G under the foundation concrete C is severely softened, the proof stress of the ground G increases by improving the area Gn with an injection material etc., and the effect of the support pile 44 can be exhibited to the maximum. .

Next, a third embodiment will be described with reference to FIG.
In the cutting apparatus 10 according to the first embodiment shown in FIGS. 1 to 4, the bit 2 is provided in only one stage in the vertical direction.
On the other hand, in the cutting device 10A of the third embodiment shown in FIG. 15, two bits 2A are provided in the vertical direction.
In FIG. 15, the cutting device 10A includes four bearing portions 1A, one bearing portion 1B, two pairs of bits 2A, two pairs of chips 3A, a pair of bit rotation shafts 4A, and an upper guide. A member 6, a lower guide member 7, and a center shaft 20 are provided.
The four bearing portions 1A and the one bearing portion 1B are fixed to the shaft portion 201 of the center shaft 20 with an interval substantially equal to the thickness of the members 2a and 2b constituting the bit 2A. Such a structure can be manufactured by machining, for example, by applying the method described above with reference to FIGS.

The four bearing portions 1A have shaft through holes 1Ah at two locations.
The bearing portion 1B has the same outline as that of the bearing portion 1A, and through female threads 1Ba are formed at the same positions as the two shaft through holes 1Ah of the bearing portion 1A.
As described in FIGS. 1 to 4, the bit 2A has a radially inner region including an upper member 2a and a lower member 2b, and a gap between the upper member 2a and the lower member 2b. 1 A of bearing parts are clamped. The bit 2A, the upper member 2a, and the lower member 2b are pivotally supported by the bearing portion 1A via the bit rotation shaft 4A.
The chip 3A is attached to the radially outer end of the bit 2A.
The bit rotation shaft 4A is constituted by a bolt having a long shaft portion, and a male screw 4Ab at the tip thereof is screwed into a penetrating female screw 1Ba formed in the bearing portion 1B.

The center shaft 20 has a shaft portion 201 and an upper end male screw portion 202. The upper end male screw portion 202 is formed at the upper end of the shaft portion 201. Reference numeral 203 denotes a lower end portion in the vertical direction of the shaft portion 201.
The upper end male screw portion 202 is screwed and connected to a female screw (not shown) formed at the lower end of the shaft portion of the upper guide member 6.
Two annular grooves (not shown) are formed above the shaft portion of the upper guide member 6, and a retaining ring 81 is attached to the annular groove to sandwich the ball bearing 60. A donut-shaped member is mounted on the outer peripheral side of the outer race of the ball bearing 60 to constitute the upper guide member 6.

A lower guide member 7 is rotatably attached to the lower end portion 203 of the center shaft 20 via a ball bearing 70.
The ball bearing 70 is prevented from falling off from the lower end portion 203 by the retainer 8. The retainer 8 is a disk-shaped member in which a through hole (bolt insertion hole) 8a is formed at the center of the disk, and the outer diameter of the retainer 8 is larger than the diameter of the lower end portion 203. It is set smaller than the inner diameter.
A female screw 203 a is formed on the lower end surface 203 e of the lower end portion 203, and the female screw 203 a is engaged with the male screw 9 a of the stud bolt 9 to attach the retainer 8 to the lower end surface 203.

The upper guide member 6 and the lower guide member 7 are substantially the same as the inner diameters of the reinforcing bar insertion holes drilled in the floor board S (or the floor board S, the foundation concrete C, and the ground G) by a diamond bit (not shown). It has a slightly smaller outer diameter and functions as a guide member or pilot member of the cutting apparatus 10A.
It is also effective to attach the upper guide member 6 and the lower guide member 7 to the cutting device 10 shown in the first embodiment and the second embodiment of the present invention.
It may be possible to omit either the upper guide member 6 or the lower guide member 7 depending on the condition of the ground.

As described above, in the cutting apparatus according to the third embodiment, as shown in FIG. 15, two bits 2A are provided on the left and right sides, that is, in the vertical direction.
Since the tip 3A provided at the tip of each of the two-stage bits 2A cuts the inner wall of the reinforcing bar insertion hole, a large number of recesses (four in FIG. 15) can be formed at the same time. Therefore, the efficiency of the roughing work and the work of expanding the inner diameter of the reinforcing bar insertion hole is improved.

In the third embodiment, the radially inner sides of the plurality of bits 2A (the opposite end portion of the chip 3A: a base portion) are respectively formed into two forks (upper member 2a, lower member 2b), and the base portions formed into two forks. Are inserted between the three bearing portions 1A, and are rotatably attached by a bit rotating shaft 4A.
Thereby, although the thickness of the head (radially outward) of the bit 2 is large, each thickness of the base is configured to be small.
Since the area where the bit rotation shaft 4A and the base portion of the bit 2A are in contact with each other is small, the frictional force when the bit 2A rotates can be reduced, and smooth roughening can be realized.
Also in the first embodiment, the inner side in the radial direction of the bit 2 (the opposite end portion of the chip 3: a base portion) is formed into a bifurcated portion by the upper member 2 a and the lower member 2 b, and the base portion formed at the bifurcated portion is used. Since the bearing portion 1 is sandwiched and rotatably mounted by the bit rotating shaft 4, the thickness dimension of the head portion (outward in the radial direction) of the bit 2 is increased. Thereby, the surface which attaches the chip | tip 3 which strikes the inner wall face of the insertion hole H can be designed large.

Next, a fourth embodiment will be described with reference to FIGS.
The cutting device 10B of the fourth embodiment shown in FIGS. 16 to 19 is compared with the cutting device (first embodiment) shown in FIGS. 1 to 4 and the cutting device (third embodiment) shown in FIG. The vertical dimension L of the bit 2B is very long.
By increasing the vertical dimension L of the bit 2B, the diameter expansion / reduction operation of the bit is stabilized during the roughing operation, and a recess or groove is formed on the inner wall surface of the reinforcing bar insertion hole. I can do it.

In the fourth embodiment shown in FIGS. 16 to 19, since the vertical dimension of the bit rotation shaft 4B is long, the opening / closing (expansion / reduction) operation of the bit 2B is stabilized.
Further, by increasing the vertical dimension L of the bit 2B, the bit weight can be designed to be larger than that of the apparatus of the first embodiment.
Here, as described above with reference to FIG. 8, when the cutting device 10 is installed in the reinforcing bar insertion hole H and rotated, the bit 2 of the cutting device 10 is inserted into the tip 3 and the reinforcing bar insertion hole H. The collision with the wall surface is used as a reaction force to close one end. However, due to the centrifugal force generated by the continuous rotation of the cutting device 10, it is pushed out again in the diameter increasing direction and collides with the inner wall surface of the reinforcing bar insertion hole H.
In the present invention, coarsening and grooving are performed by this continuous motion. However, by increasing the weight of the bit 2, even when the reaction force is applied, the amount by which the bit 2 moves in the closing direction is reduced. it can.
Further, the recoil of the bit 2 is controlled by keeping the rotational speed of the cutting device 10 low, and the tip 3 is made of a carbide tip such as diamond, so that the tip 3 rubs against the inner wall surface of the reinforcing bar insertion hole H. It can also be cut.
However, if the vertical length of the bit rotation shaft 4B is too long, the bit weight becomes too large, which is inconvenient for the operations of expanding and reducing the diameter.
In the example of FIGS. 16 to 19, the vertical dimension L of the bit 2B is 150 mm with respect to the outer dimension diameter (the radial dimension when the bit 2B is reduced) of 55 mm when the bit 2B is reduced in diameter. is there.
Here, when the vertical dimension L of the bit 2B is shorter than twice the outer diameter, the effect of stabilizing the opening / closing (expansion / reduction) operation of the bit 2B is reduced. On the other hand, when the vertical dimension L of the bit 2B exceeds four times the outer diameter, opening / closing (expansion / reduction) operation becomes difficult due to the weight of the bit 2B.

16 and 17, the cutting device 10B has an upper bearing portion 1C, a lower bearing portion 1D, a pair of bits 2B, a pair of tips 3B, and a pair of bit rotation shafts 4B. Yes.
The upper bearing portion 1C has a small diameter portion 11C, a large diameter portion 12C, and a tapered portion 13C. The tapered portion 13C integrally connects the small diameter portion 11C and the large diameter portion 12C.

The small-diameter portion 11C is formed with a female screw not clearly shown in the figure, and the female screw is screwed with a male screw (not shown) formed at the lower end of the rod RdA.
Here, the state where the pair of bits 2B is reduced in diameter (not cut) is shown in FIGS.
In FIG. 16, female screws 14C are formed at two locations on the lower end surface of the large diameter portion 12C. The female screw 14C is screwed with a male screw 41B formed at the end of the bit rotation shaft 4B.

The lower bearing portion 1D is provided with a large diameter portion 11D and a small diameter portion 12D.
The diameter of the large diameter portion 11D is set larger than the diameter (maximum diameter) of the outer end when the bit 2B is reduced in diameter.
In the small diameter portion 12D, an annular groove 13D is formed in the vicinity of the lower end portion (the end portion on the side separated from the large diameter portion 11D), and a retaining ring 90 is attached to the annular groove 13D.
A ball bearing 70 is mounted between the boundary between the small diameter portion 12D and the large diameter portion 11D and the retaining ring 90.

FIGS. 18 and 19 show a state in which the cutting device 10B of the fourth embodiment expands the diameter and performs a roughing operation.
About the aspect of the roughening operation | work in the cutting device 10B of FIGS. 16-19, it is the same as that of having demonstrated in FIGS.
Configurations and operational effects other than those described above in the fourth embodiment of FIGS. 16 to 19 are the same as those of the embodiment of FIGS.

  It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Bearing part 2 ... Bit 3 ... Chip 4 ... Bit rotating shaft 5 ... Stopper pin 6 ... Upper guide member 7 ... Lower guide member 8 ... Retainer 10- ..Cutting device 44 ... Support pile

Claims (1)

Drilling a bore hole (H) in the concrete layer (S), cutting the inner wall surface of the concrete hole (H) to form a recess, inserting a reinforcing bar, and reinforcing an existing concrete structure filled with mortar, In the repair method, a rod (Rd) to which a rotational force is applied by a rotational drive source provided on the ground side, a shaft portion (SH) connected to the ground side end portion of the rod (Rd), and the shaft A flat plate member (1) fixed to the portion (SH), a bit (2) provided rotatably on the flat plate member (1), and a chip (3) provided at the tip of the bit (2) , bit (2) is prepared stopper (5) a cutting machine and a (10) provided in the plate member (1) so as not excessively rotated, the bit (2), said rod (Rd) There is located radially inwardly in the case of not rotating the rod (Rd There was rotated around the rotation axis (4) when rotating at 300rpm or more, the and the chip (3) above end provided with is located radially below the concrete layer (S) Boring holes (H) are drilled up to the regions (C, G), the cutting device (10) is disposed in the boring holes (H), the rod (Rd) is rotated at 300 rpm to 1000 rpm, and the centrifugal force The diameter of the bit (2) is further expanded, and the tip (3) provided at the tip of the bit (2) is caused to collide with the inner wall surface of the concrete layer (S) to form a recess in the inner wall surface of the borehole. At the same time, when the tip (3) hits the inner wall surface of the borehole (H), the bit (2) provided with the tip (3) returns radially inward, and the concrete layer (S) of the borehole (H) In the lower area (C, G) The rod (Rd) is rotated at an arbitrary position for an arbitrary time, and the tip (3) at the tip of the bit (2) is made to collide with the inner wall surface of the boring hole (H) to enlarge the inner diameter of the boring hole (H). A method for repairing and reinforcing an existing concrete structure.

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