JP3536155B2 - Apparatus and method for inducing crack in concrete structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crack inducing apparatus and a crack inducing method for a concrete structure which can be applied when constructing a wall of a structure such as a retaining wall, a continuous underground wall or a building.

[0002]

2. Description of the Related Art As shown in FIG. 10, when a concrete wall a is constructed, cracks are generated due to internal stress caused by heat of hydration of concrete and shrinkage of the concrete after drying. As a countermeasure against such cracking of the concrete wall body a, a joint portion b is provided on the surface of the wall body a. By providing the joint portion b, the cross-section of the wall body a is broken, and the generation of the crack c is concentrated on the joint portion b. Then, the repair material is injected from the crack c portion of the surface of the wall body a and hardened to repair the crack c.

[0003]

Problems to be Solved by the Invention The above-described crack inducing technique has the following problems. <A> When the joint portion b is cut into a large size, the effect of inducing the crack c is increased, but the strength of the wall a is reduced and the repair load is increased. On the other hand, if the joint b is formed small, the strength of the wall a and the burden of repair can be reduced, but the effect of inducing cracks is reduced. <B> When the reinforcing bars are arranged in the wall body a, the formation depth of the joint portion b formed on the side surface of the wall body a is restricted. Therefore, if the wall a is large and thick, even if the joint b is formed, the crack c cannot be surely induced at that position. <C> When the back side of the wall a is covered with earth and sand, the repair material is injected only into the front side of the wall, so that the crack c
It is difficult to fill the entire area with the repair material. For that reason,
There remains anxiety about the water stop of the wall a.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to reliably generate a crack at a predetermined position and to bring the crack into the crack regardless of the back side condition. It is an object of the present invention to provide a crack inducing device and a crack inducing method for a concrete structure that can be filled with a repair material.

[0005]

[Means for Solving the Problems] That is, the present invention is a device for inducing cracks in a structure, which is provided inside the concrete structure when the structure is constructed, and has a tubular cross-section reduction body, A crack inducing device for a concrete structure, which is formed by an injection pipe that is inserted into the cross-section reduction body and has one end opened at the outer circumferential surface of the cross-section reduction body. Further, the present invention is a device for inducing cracking in a structure when constructing a concrete structure, which is a tubular cross-section reduction body and is inserted into the cross-section reduction body, one end of which Comprises an injection pipe opened at the outer peripheral surface of the cross-section reducing body, and a water stop plate attached to the outer peripheral surface of the cross-sectional reducing body,
It is a crack inducing device for concrete structures. Further, the present invention is a device for inducing cracking in a structure which is disposed inside when constructing a concrete structure, and has a tubular cross-section reduction body, and is inserted into the cross-section reduction body, one end of which has a cross section. A crack inducing device for a concrete structure, comprising an injection pipe opened on the outer peripheral surface of the reduction body and a water stop plate attached to the outer peripheral surface of the reduction body. Further, the present invention, in the crack inducing device for a concrete structure described above, comprising an inner pipe insertable into the injection pipe, arranging a plurality of branch pipes, each branch pipe can be injected in several stages. It is a characteristic crack inducing device for concrete structures. Further, the present invention is the crack inducing device for a concrete structure according to the crack inducing device for a concrete structure, wherein at least two injection pipes are arranged so that the lower ends of the injection pipes can communicate with each other. Further, the present invention, in the crack inducing device for a concrete structure described above, characterized in that an elastic material is attached to the outer peripheral surface of the cross-section reducing body and around the opening of the injection pipe, the concrete structure. It is a crack inducing device. Further, the present invention is a crack inducing device for a concrete structure as described above, characterized in that an elastic closing body having a pinhole opened is attached to an opening in the injection pipe. is there. Further, the present invention is, in the crack inducing device for a concrete structure described above, characterized in that a check valve made of an elastic material that allows water to pass only to the outside is installed in an opening portion in the injection pipe, the concrete structure. It is a crack inducing device. Further, the present invention is a method of inducing cracks occurring in a concrete structure at the time of constructing the structure, wherein the crack inducing device described above is embedded in the structure, and a cross-section loss due to embedding of the inducing device is caused. This is a method for inducing cracks in a concrete structure, in which a crack is caused between the outer surface of the structure and the inducing device, and a repair material is injected into the crack from the cross-sectional reduction body of the inducing device. Furthermore, the present invention is the method for inducing cracks in a concrete structure, wherein in the method for inducing cracks in a concrete structure described above, a plurality of the crack inducing devices can be embedded along the direction in which cracks occur.

[0006]

Embodiment 1 An embodiment according to the present invention will be described below with reference to the drawings.

<A> Inducing device (FIG. 1) FIG. 1 is a perspective view of the inducing device 10. The trigger device 10 is
An injection pipe 30 is inserted into the cross-section reduction body 20, and a water stop plate 40 is connected to the outer periphery of the injection pipe 30. Hereinafter, each part will be described in detail.

<B> Cross-section reduction body (FIGS. 1 and 2) The cross-section reduction body 20 is made of a hollow and rigid pipe body as shown in FIG. 1, and is disposed upright in the wall body 50 to be constructed. It By disposing the cross-section reduction body 20 in the wall body 50,
It has a function of forming a defective section in the wall body 50 and inducing cracks. That is, the cross section of the wall body 50 is reduced by the amount of the cross-section reduction body 20 in the wall body 50. Therefore, when an expansion stress or a contraction stress acts on the wall body 50, the stress concentrates on a small portion of the cross section and cracks occur. Further, as shown in FIG. 2, it is preferable that the outer diameter d of the cross-section reducing body 20 is about 30% of the thickness T of the wall body 50. That is, if the outer diameter d of the cross-section reduction body 20 is too small, cracks cannot be reliably generated, and the outer diameter d
If it is too large, the workability and economy will be poor.

<C> Water stop plate (FIG. 1) A water stop plate 40 is continuously provided on the outer peripheral surface of the cross-section reduction body 20 along the longitudinal direction of the wall body 50. Water stop plate 40
Is a member for preventing water leakage due to communication between the cracks on the front surface side and the cracks on the rear surface side of the wall body 50, and two members are provided at positions opposite to the cross-section reducing body 20. The number of the water blocking plates 40 installed may be singular or two or more as needed. The shape of the water blocking plate 40 is not limited to the one shown in FIG. 1, but may be one having a concave or convex portion formed on the surface or one having a thick portion formed at the end. Further, if the water blocking plate 40 is formed of the same material as the cross-section reducing body 20 and has an integral structure, the water blocking property is improved. The water blocking plate 40 may not be installed if water blocking can be ensured by the presence of the cross-section reducing body 20.

<D> Injection Pipe (FIGS. 1 and 3) An injection pipe 30 is inserted into the cross-section reducing body 20. The injection pipe 30 is a member that forms an injection path for injecting the repair material 60 into the cracks formed around the cross-section reduction body 20, and a main pipe 31 arranged in the axial direction of the cross-section reduction body 20, It is configured by a branch pipe 32 that branches from the main pipe 31 and opens to the outer peripheral surface of the cross-section reduction body 20. The opening position of the branch pipe 32 is preferably at a substantially intermediate position where the water blocking plates 40, 40 are connected. The diameters of the main pipe 31 and the branch pipe 32 are as small as possible in order to reduce the injection amount of the repair material 60. This injection tube 3
By providing a plurality of branch pipes 32 at 0, the repair material 60 can be injected in several stages for each upper portion of the branch pipe 32, and the repair material 60 can be surely injected. Also, as shown in FIG.
An elastic closing body 33 is attached to an opening portion in the branch pipe 32. The elastic blocking body 33 is made of an elastic member such as rubber and is a member for preventing concrete or the like placed around the cross-section reducing body 20 from the opening portion of the branch pipe 32 from entering the injection pipe 30. . The elastic closing body 33 has a pinhole 331 formed in the axial direction of the branch pipe 32. The pinhole 331 is a through hole that is normally in a closed state and opens only when a liquid such as the repair material 60 is press-fitted into the open end of the pinhole 331. Further, a band-shaped elastic material 21 is attached to the outer peripheral surface of the cross-sectional reduction body 20 and around the opening of the branch pipe 32. The elastic member 21 is made of an elastic member such as rubber or sponge, and is a member that guides the repair material 60 discharged from the branch pipe 32 to the crack portion through the surface thereof. Since the cracks occur in the vertical direction of the wall body 50, it is preferable to form the elastic material 21 in a horizontally long shape.

<E> Repair Material The repair material 60 may be a hardener having fluidity such as epoxy resin type, urethane type and cement type. In particular, a fine particle cement-based curing agent that hardens even in the presence of water and has excellent fluidity is a suitable material.

<F> Wall body The wall body 50 to which the crack inducing device 10 is installed is a wall body constructed continuously to some extent. The installation position of the crack inducing device 10 is not the end portion (joint portion) of the wall body 50, but the continuous middle portion of the wall body 50.

[0013]

[Operation] Next, a crack inducing method will be described.

<A> Cracking step (FIG. 1) The induction device 10 is vertically arranged at approximately the central portion between the compression reinforcing bar (front reinforcing bar) and the tensile reinforcing bar (rear reinforcing bar) of the wall body 50 in accordance with the reinforcing bar assembly. To do. A plurality of the triggering devices 10 may be arranged at predetermined intervals along the continuous direction of the wall body 50,
You may arrange independently. The direction of the water stop plate 40 of the inducing device 10 is aligned substantially parallel to the longitudinal direction of the wall body 50. Next, a form is installed around the reinforcing bar and the inducing device 10, and concrete is placed in the form. At this time, the upper end of the inducing apparatus 10 is set to a position slightly higher than the concrete pouring upper surface so that the repair material 60 can be injected from above the wall body 50 later. Further, since the elastic closing body 33 is attached to the opening portion of the branch pipe 32, the concrete cast around the inducing device 10 is filled with the injection pipe 30, that is, the main pipe 31.
And does not penetrate into the branch pipe 32. Trigger device 10
Due to the burying, the cross section of the wall body 50 is in a state of being greatly reduced in the portion of the inducing device 10.

After several hours have passed since the concrete was poured,
Stress is generated inside the wall body 50 due to heat of hydration of concrete. Since the stress concentrates on a small part of the cross section of the wall body 50, the position where the inducing device 10 is embedded, that is, the cross section reducing body 20
A crack 51 is formed between the wall and the front and back surfaces of the wall body 50. By thus burying the inducing device 10, it is possible to reliably cause the crack 51 to occur at an arbitrary position in the wall body 50. In addition, notch-shaped joints may be formed on the surface of the wall body 50 so that the cracks 51 do not spoil the appearance of the wall body 50. In that case, a crack 51 occurs at a predetermined position (joint portion) on the surface of the wall body 50.
The restoration marks are finished beautifully.

<B> Injecting repair material (FIGS. 3 and 4) As shown in FIG. 3, the inner pipe 34 extends from the upper end of the main pipe 31 to the inside thereof.
Through. Next, the inner pipe 34 is gradually pulled up above the main pipe 31 while press-fitting the repair material 60 into the inner pipe 34. By injecting the branch pipe 32 into the main pipe 31 in several stages, the repair material 60 can be surely injected. The press-fitted repair material 60 reaches the inside of the branch pipe 32 from the lower end of the inner pipe 34 through the inside of the main pipe 31. Then, it is discharged to the outside of the cross-section reducing body 20 through the pinhole 331 of the elastic closing body 33 and filled in the crack 51.

On the other hand, as shown in FIG.
2 It may not occur at the opening. Even in such a case, the repair material 60 released from the elastic blocking body 33 is filled in the cracks 51 along the surface of the elastic material 21 attached to the outer peripheral surface of the cross-section reducing body 20. That is, the elastic material 21 contracts due to the release of the repair material 60, and allows the repair material 60 to flow. Therefore, the repair material 60 is surely cracked 5
1 can be filled.

<C> After filling the filling / repairing material 60 in the cross-section reduction body, mortar or the like is filled between the cross-section reduction body 20 and the injection pipe 30 (main pipe 31, branch pipe 32) for repair.

[0019]

Second Embodiment In some cases, the injection pipe 30 may not be arranged in the cross-section reducing body 20. In that case, the wall body 50 is cracked 51
After generating the cracks, the repair material 60 may be filled into the cracks 51 from the front surface, the back surface, or the upper end surface of the wall body 50.

[0020]

[Third Embodiment] The main pipe 31 of the injection pipe 30 is replaced by a cross-section reducing body 2.
There may be a case where multiple units are installed in 0. For example, as shown in FIG. 5, two main pipes 31a and 31b that are continuous at the lower end are arranged, and a branch pipe 32 is branched from each of the main pipes 31a and 31b to reduce the cross-section reduction body 2.
0 Open on the opposite side of the outer peripheral surface. The repair material 60 can be injected from one of the main pipes 31a and 31b and discharged from the other to check the filling state.
After injecting the repair material 60, the cleaning water is injected from one of the main pipes 31a and 31b and discharged from the other together with the repair material 60 remaining in the injection pipe 30 (the main pipe 31 and the branch pipe 32) to clean the inside of the injection pipe 30. I do. Then, after the wall body 50 is constructed, the upper end portion of the injection pipe 30 is opened on the surface of the wall body 50 as an injection hole. By cleaning the injection pipe 30 in this manner, even when the crack 51 occurs again after the completion of the construction of the wall body 50, the repair can be performed. The injection pipe 30
In order to enhance the cleaning effect inside, the branch pipe 32 may be formed to be extremely short, or the main pipe 31 may be arranged along the inner peripheral surface of the cross-section reducing body 20 without providing the branch pipe 32.

[0021]

[Embodiment 4] The means for closing the opening of the branch pipe 32 is not limited to the elastic closing body 33, but may be a valve structure which allows only one-way flow. For example, as shown in FIG. 6, the non-stretchable sheet material 21 is formed on the surface of the elastic material 21a.
1 is attached and formed so as to cover the opening portion of the branch pipe 32. Even if concrete is placed around the cross-section reduction body 20, the sheet material 211 does not expand, so that the concrete does not enter the branch pipe 32. On the other hand, at the time of injecting the repair material 60, the end portions of the elastic materials 21a, 21a are opened and the repair material 60 can be discharged to the outside of the cross-section reducing body 20.

[0022]

Fifth Embodiment When the wall body 50 has a large thickness, a plurality of inducing devices 10 may be arranged along the thickness direction thereof as shown in FIG. By disposing a plurality of inducing devices 10, it is possible to surely cause a crack in a large-sized wall body 50 by providing a cross-section defect, and also to induce a crack 51 from the inside of the wall body 50 through the cross-section reducing body 20. can do.

[0023]

Sixth Embodiment The cross-sectional shape of the cross-section reducing body 20 is not limited to the circular shape, but may be other shapes. In particular, if the cross-sectional reduction body 20 has a rhombic cross-sectional shape as shown in FIG. 8, cracks are likely to occur at the opening of the branch pipe 32.

[0024]

Seventh Embodiment As shown in FIG. 9, the branch pipe 32 may have a laterally elongated opening shape. In this case, the repair material 6 is also applied to the crack 51 that is generated from the central portion of the cross-section reduction body 20.
0 can be filled in the crack 51.

[0025]

[Embodiment 8] The inducing device 10 may of course be used for inducing a concrete structure other than the wall body 50.

[0026]

Since the present invention is as described above, the following effects can be obtained. <A> A cross-section reduction body was embedded in the concrete structure. Therefore, it is not necessary to form joints on the surface of the concrete structure for the purpose of cracking. That is, it is only necessary to form joints with shallow cuts on the surface of the concrete structure for the purpose of aesthetics. Therefore, it is possible to reliably generate a crack at a predetermined position without performing a repair work by boring from the outside. <B> Even if the structure is large and thick, cracks can be surely induced at a predetermined position. <C> The repair material can be filled into the crack through the cross-section reducing body embedded in the concrete structure. Therefore, even if the structure is a retaining wall or a mountain retaining wall and earth and sand are located on the back surface thereof, the repair material can be filled into the crack. Therefore, the water blocking property of the wall is not impaired. <D> An injection tube was inserted through the body with a reduced cross section. Therefore, if the cross-section reduction body has a large diameter and the injection pipe has a small diameter,
The effect of inducing cracks can be enhanced and the amount of repair material used can be reduced. Therefore, cracking can be economically induced. <E> By arranging a plurality of injection pipes and connecting the lower ends of the injection pipes to each other, the injection pipes can be washed and used again after use. Therefore, even if cracks occur again after the construction of the structure is completed, it is possible to repair them. <F> An elastic material was attached to the outer peripheral surface of the reduced cross-section body around the opening of the injection pipe. Therefore, even if the cracks are displaced from the opening position of the injection pipe, the repair material can flow along the surface of the elastic material due to the contraction of the elastic material and be filled in the cracks. <G> If an elastic blocker with a pinhole opened is attached to the opening in the injection pipe, and a valve element made of an elastic material that allows water to pass only to the outside is installed in the opening in the injection pipe.
Even if concrete is placed around the crack inducing device, it is possible to prevent the concrete from entering the injection pipe. <H> By burying a plurality of crack inducing devices along the direction in which cracks occur, it is possible to reliably cause cracks even in large structures.

[Brief description of drawings]

FIG. 1 is a perspective view of a crack inducing device.

FIG. 2 is a horizontal sectional view of a crack inducing device.

FIG. 3 is a vertical sectional view of a crack inducing device.

[Figure 4] Illustration of injection of repair material

FIG. 5 is an explanatory diagram of the third embodiment.

FIG. 6 is an explanatory diagram of Example 4.

FIG. 7 is an explanatory diagram of Example 5.

FIG. 8 is an explanatory diagram of Example 6.

FIG. 9 is an explanatory diagram of Example 7.

FIG. 10 is an explanatory diagram of a conventional technique.

Continuation of front page (56) Reference JP-A-6-248731 (JP, A) JP-B-53-10378 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) E04G 21 / 02 103 E04G 9/10 104 E04G 15 / 06,23 / 02 E04B 2/84 E04H 9/02 321

Claims (9)

(57) [Claims] 1. A device for inducing cracking in a structure when constructing a concrete structure, the device being a tubular cross-section reduction body, and being inserted into the cross-section reduction body, one end of which is provided. Cross-section reduced outside the body
A crack inducing device for a concrete structure, which is composed of an injection pipe opened at the peripheral surface . 2. A device for inducing cracks in a structure when constructing a concrete structure, the device being a tubular cross-section reduction body, and being inserted into the cross-section reduction body, one end thereof. A device for inducing cracking in a concrete structure, comprising: an injection pipe opened on the outer peripheral surface of the reduced cross section, and a water stop plate attached to the outer peripheral surface of the reduced cross section . 3. The concrete structure according to claim 1 or 2.
In the crack inducing device , at least two injection pipes are arranged and the lower end of the injection pipe is
A crack inducing device for concrete structures, characterized by being connected . 4. The crack inducing device for a concrete structure according to any one of claims 1 to 3 , which is an outer peripheral surface of the cross-section reducing body and is an opening portion of the injection pipe.
A device for inducing cracks in concrete structures, characterized in that an elastic material is attached to the periphery of the concrete structure. 5. The crack inducing device for a concrete structure according to claim 1 , wherein a pinhole is opened in the opening portion in the injection pipe.
A crack inducing device for a concrete structure, which is equipped with an elastic blocker. 6. The crack inducing device for a concrete structure according to any one of claims 1 to 5 , wherein water is allowed to flow only to the outside in an opening portion in the injection pipe.
A crack inducing device for concrete structures, which is equipped with a check valve made of elastic material . 7. A structure for constructing a concrete structure
A method for inducing a crack that occurs in a crack, the crack inducing device according to any one of claims 1 to 6.
By embedding the device in the structure and embedding its triggering device
Cross-section defects cause cracks between the outer surface of the structure and the trigger device.
A method for inducing cracks in a concrete structure , characterized by causing the cracks. 8. A method for inducing cracks occurring in a concrete structure when constructing the concrete structure, the crack inducing device according to any one of claims 1 to 6.
By embedding the device in the structure and embedding its triggering device
Cross-section defects cause cracks between the outer surface of the structure and the trigger device.
For the crack to occur, repair material from the cross-sectional reduction body of the induction device
A method for inducing cracks in concrete structures by injecting . 9. The concrete structure according to claim 7 or 8.
In the method for inducing cracks of an object, the crack inducing device is installed along the direction of the cracks.
A method for inducing cracks in a concrete structure , which is characterized in that a plurality of them are buried in the structure.