JP2001140595A - Repairing method for cold joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fundamental repairing method for a cold joint. SOLUTION: A cut groove 24 is first formed along a cold joint section 12 by a water jet in this repairing method. After the prescribed cut groove 24 is formed, a hardening repairing material 30 is filled in the cut groove 24, and the filled repairing material 30 is hardened as time elapses. The repairing material 30 has little shrinkage, a good filling property, and the same shearing strength as that of concrete, and it can be selected from nonshrinkage mortar, fiber-reinforced mortar, and pea gravel high-fluidity concrete. When the hardening repairing material 30 is filled and hardened in the cut groove 24, healthy portions on both sides of the cold joint section 12 removed for forming the cut groove 24 are integrated together by the hardened repairing material 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing a cold joint.

[0002]

2. Description of the Related Art In the case of cold joints, when concrete is continuously poured in, the transport of concrete is interrupted, so that the preceding concrete placed first and the subsequent concrete placed later are completely integrated. A joint that has not been transformed.

When such a cold joint occurs in a concrete structure, it becomes a weak point of the structure. Therefore, conventionally, the repair has been performed by the method shown in FIGS.

The method of repairing a cold joint shown in FIG. 1 shows a case where a cold joint 2 occurs in the lining concrete 1 of a tunnel.

[0005] When repairing the cold joint 2,
A steel material 3 such as an angle is disposed so as to straddle the generating portion of the cold joint 2, and both ends of the steel material 3 are anchored 4.
Fix with.

[0006] A plurality of such steel materials 3 are installed at predetermined intervals along the cold joint 2 extending along the tunnel axis direction.

However, such a conventional method of repairing a cold joint has the following technical problems.

[0008]

That is, the conventional repair method shown in FIGS. 5 and 6 is an effective method for preventing the concrete from falling off by fixing the steel material 3 with the anchor 4. The cold joint 2 which is a discontinuous surface generated in the concrete structure is not integrated, and the cold joint 2 is not fundamentally repaired.

In other words, in the above-described conventional method for repairing a cold joint, as a reinforcement for the cold joint 2, a weak portion is restrained by a steel material 3 such as an angle from the outside, so that the vicinity of the cold joint 2 is peeled or collapsed. It was a way to prevent.

[0010] However, such a repairing method is intended only to prevent peeling or collapse near the cold joint 2 and is not a method aiming at restoring the strength of the concrete structure.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a method capable of fundamentally repairing a cold joint.

[0012]

In order to achieve the above object, the present invention provides a method for forming a cutting groove to a predetermined depth by jetting a water jet along a cold joint generated in a concrete structure, and thereafter, The groove is filled with a curable repair material to be cured. According to the method of repairing a cold joint configured as described above, a cutting groove is formed to a predetermined depth by spraying a water jet along a cold joint portion generated in a concrete structure. The weak points of the concrete structure and the cold joints that are present are eliminated. In this case, since the cold joint portion usually has a thickness of about several centimeters, a cutting groove having a width larger than this, for example, a cutting groove having a thickness of about 5 to 20 cm may be formed by jetting a water jet.
Then, in the present invention, the hardening repair material is filled and hardened in the cutting groove formed by the jet of the water jet, so that when the repair material hardens, the sound portions on both sides of the cold joint portion removed by the cutting groove are hardened. These are integrated with each other with the cured repair material. For this reason, the cold joint, which is a discontinuous surface generated in the concrete structure, is integrated with the repair material, so that the cold joint can be repaired fundamentally. In this case, the inner surface of the cutting groove formed by the jet of the water jet is peeled and removed of the mortar component by the jet pressure of the water jet, and the aggregate is exposed to the surface and roughened. Since the shear strength between the material and the repair material is increased, and the repair material is filled in the groove, the hardened repair material in the groove hardly falls off. The repair material has a small shrinkage, a good filling property, and a shear strength similar to that of concrete,
It can be selected from non-shrink mortar, fiber reinforced mortar, bean gravel high fluidity concrete. The repair material can be injected into the cut groove at a predetermined pressure. Also,
The repair material can be spray-filled into the cut groove.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 to 3 show one embodiment of a method for repairing a cold joint according to the present invention.

The method of repairing a cold joint shown in FIG. 1 is applied to the repair of a cold joint 12 generated in tunnel lining concrete 10. When forming the tunnel lining concrete 10,
For example, as shown in FIG. 4, a metal foam form 16 is provided at a predetermined interval inside a digging surface on which primary lining or the like (not shown) has been applied, and the digging surface and the metal foam During this, concrete is poured through the concrete supply pipe 18.

When placing such concrete,
When the concrete supply from the concrete supply pipe 18 is stopped for some reason, the preceding concrete 20 poured first and the later concrete 22 poured later.
A cold joint 12 in which the two are not integrated occurs between the two.

The locations that can become cold joints 12 are usually the leading and trailing concrete 20,
22 is a seam, and there is a line along the seam, especially when cracks and openings exist along this line, or when powder due to breathing is observed along the line Is considered to be almost a cold joint.

The cold joint portion 12 does not occur in a straight line but in a curved or meandering manner along the axial direction of the tunnel as shown in FIG.

When the presence of such cold joints 12 in the lining concrete 10 is confirmed by the above-mentioned observation or the like, or when the cold joints 12 may be hit. For example, when the potential of the cold joint portion 12 is recognized as described above, in this embodiment, a drilled groove 24 is first formed along the cold joint portion 12 as shown in FIG.

The drilled groove 24 is provided with a head 28 provided with a nozzle 26 for jetting jet water W in a tunnel, and directs the jet water W from the nozzle 26 toward the cold joint portion 12 at a predetermined pressure, for example, , 1000-25
It is formed by a water jet sprayed at about 00 kg / cm ² .

When the water jet having such a configuration is used, the cutting groove 24 can be reliably formed along the curved or meandering cold joint portion 12 by operating the head 28.

In this case, the cold joint 12
Usually, since the thickness is about several cm, a cutting groove 24 having a width larger than this, for example, a cutting groove having a thickness of about 5 to 20 cm may be formed by jetting a water jet.

The depth of the cutting groove 24 is, for example, in the case of the present embodiment, the repair material 3 described later in the cutting groove 24.
When filling 0, it is necessary not to penetrate through the thickness of the lining concrete 10 because of the necessity of preventing the leakage.

In this manner, the cold joint 12
Along the cutting groove 24
Is formed to a predetermined depth, the formation of the cutting groove 24 removes the cold joint portion 12 which is a weak point of the lining concrete 10.

In this case, by adjusting the injection pressure of the water jet, it is possible to cut only the deteriorated portion while leaving the healthy portion of the lining concrete 10. When formed, since the deteriorated portion corresponds to the cold joint portion 12, the cutting groove 24 is necessarily formed along the cross-sectional direction and the longitudinal direction of the cold joint portion 12.

When the predetermined cutting groove 24 is formed as described above, the hardening repair material 30 is filled in the cutting groove 24 as shown in FIG.
Cures over time.

The repair material 30 used in this embodiment has a small shrinkage, a good filling property, a shear strength comparable to that of concrete, a non-shrink mortar, a fiber reinforced mortar,
Can be selected from pea gravel high fluidity concrete.

The repair material 30 can be injected into the cutting groove 24 at a predetermined pressure, or can be spray-filled into the cutting groove 24.

Then, the hardening repair material 30 is filled and hardened in the cutting groove 24 formed by the jet of the water jet, and the sound portions on both sides of the cold joint portion 12 removed by the formation of the cutting groove 24 are joined together. Are integrated with the cured repair material 30.

Therefore, the cold joint 12 which is a discontinuous surface generated in the concrete structure can be integrated with the repair material, and the cold joint 12 can be repaired fundamentally.

In this case, the inner surface of the cutting groove 24 formed by the jet of the water jet is peeled and removed of the mortar by the jet pressure of the water jet, and the aggregate is exposed to the surface and roughened. , Sound parts and repair materials 30
As the repair material 30 is filled in the groove 24, the repair material 30 hardened in the groove 24 hardly falls off.

The cutting groove 24 formed by the water jet shown in FIG. 2 is formed in a discontinuous state at a predetermined length along the tunnel axis direction in an intermittent manner, and is filled in the cutting groove 24. After the material 30 has hardened, a cutting groove 24 is formed in the discontinuous portion, and then the repair material 30 is filled in the groove 24 to repair the cold joint portion 12 in a continuous state.

Further, in the above embodiment, the case where the present invention is applied to the repair of the cold joint portion 12 generated in the tunnel lining concrete 10 is exemplified, but the practice of the present invention is not limited to this. The present invention can be applied to repair of a cold joint of another concrete structure provided with a joint portion in a vertical direction.

[0033]

As described above in detail, according to the method for repairing a cold joint according to the present invention, it is possible to fundamentally repair the cold joint.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a first step showing one embodiment of a method for repairing a cold joint according to the present invention.

FIG. 2 is an explanatory plan view of FIG. 1;

FIG. 3 is an explanatory sectional view of a step performed after the step shown in FIG. 1;

FIG. 4 is an explanatory diagram of a state of occurrence of a cold joint which is a repair measure of the present invention.

FIG. 5 is an explanatory sectional view showing an example of a conventional method for repairing a cold joint.

FIG. 6 is an explanatory plan view of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Lining concrete 12 Cold joint part 20 Leading concrete 22 Trailing concrete 24 Drilling groove 30 Repair material W Jet water

Claims (4)

[Claims] 1. A cutting groove is formed to a predetermined depth by spraying a water jet along a cold joint generated in a concrete structure, and thereafter, the groove is filled with a curable repair material and cured. A method for repairing a cold joint. 2. The repair material has a small shrinkage, a good filling property, a shear strength comparable to that of concrete, and is selected from non-shrink mortar, fiber reinforced mortar, and pea gravel high fluidity concrete. The method for repairing a cold joint according to claim 1, wherein: 3. The method for repairing a cold joint according to claim 1, wherein the repair material is injected into the cutting groove at a predetermined pressure. 4. The method for repairing a cold joint according to claim 1, wherein the repair material is spray-filled into the cut groove.