JP3867993B2 - Repair method for concrete wall - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for repairing a concrete wall surface by injecting a concrete repair agent into a gap such as a separation space layer or a crack generated inside the concrete wall surface.
[0002]
[Prior art]
Recently, in concrete structures, aging of concrete, neutralization due to external environment, salt damage, alkali-aggregate reaction, poor construction, drying shrinkage, vehicle vibration, occurrence of cracks due to vibration, earthquake, etc., rebar accompanying this Phenomenon that the strength decreases due to rusting, that is, deterioration of concrete is a problem. In particular, there is a risk of falling of the outer wall tile of the building and peeling of the inner wall of the tunnel due to peeling between the concrete frame layer and the underlying mortar layer.
[0003]
The exfoliation space layer generated between the concrete frame layer and the base mortar layer is typically formed with a width of about 0.2 to 1 mm at a boundary portion having a depth of 2 to 3 cm below the wall surface. Conventionally, as a method of repairing the wall surface in which the separation space layer is generated, there is a method of opening an injection hole in a concrete wall surface and injecting epoxy resin as a repair agent into the separation space layer through the injection hole. In many cases, instead of this epoxy resin, a method of injecting cement slurry has been adopted. This is because the hardened cement slurry has almost the same composition as the hardened concrete and reacts integrally with the concrete to the physical change of the outside world, so the durability after repair is much higher than the epoxy resin, The cement slurry is a mixture of mixed cement powder in water to form a slurry. Therefore, even if water remains in the release space layer, there is no inconvenience as in the case of an epoxy resin. This is because the viscosity is lower than that of the resin, and thus there are various advantages such as easy diffusion into the release space layer.
[0004]
By the way, regardless of whether the concrete repair agent is epoxy resin or cement slurry, in order to inject it, first use an electric vibration drill, diamond core drill, etc. to reach the peeling space layer on the concrete wall It is necessary to open an injection hole. FIG. 8 shows an electric drill equipped with a screw-type drill bit 80, and FIG. 9 shows a direction perpendicular to the outer wall surface using a diamond core drill 90 having a tip in which diamond abrasive grains are arranged on the tip of the cutting edge. 1 shows a conventional method of opening an injection hole in which B is a concrete frame layer, A is a mortar layer on the outside thereof, and C is a separation space layer generated between both layers A and B.
[0005]
[Problems to be solved by the invention]
However, the injection hole drilled by the conventional method has a problem that the injection is often not performed particularly when the concrete repair agent is cement slurry. As shown in FIGS. 8 and 9, this is due to the phenomenon that the thin mortar dropping pieces G generated in the process of forming the injection holes block the flow path of the repair agent to the separation space layer C. It has been elucidated by the inventor.
[0006]
That is, immediately before the tip of the screw-type drill bit 80 shown in FIG. 8 or the core drill 90 shown in FIG. 9 reaches the separation space layer C, the mortar around the tip is greatly pressed by the pressing force of the tip. Tensile stress is generated. Since the mortar material has a high compressive strength but extremely low tensile strength, a conical crack due to the tensile stress is generated starting from the contact portion with the outer peripheral edge of the bit tip, thereby causing the mortar outer wall layer A The conical mortar debris G peels off on the inner surface side of the slab, falls off to the side of the concrete skeleton layer B, and is crushed to block the groove-shaped opening of the peeling space layer C appearing on the inner peripheral surface of the injection hole all around It becomes.
[0007]
At this time, a very narrow gap exists between the mortar outer wall layer A, the mortar fallen debris G, and the concrete frame layer B, but the cement slurry injected from the injection hole is filtered when passing through this gap. As a result, clogging due to cement powder in the cement slurry occurs, and finally the cement slurry cannot be injected at all.
[0008]
Further, in the conventional injection hole forming process, in order to cool the tip of the drill and discharge the shavings from the injection hole, compressed air is supplied to the tip from the base of the drill through the inside. However, there is a problem that the function of cooling the tip and discharging the shavings is insufficient only by supplying the compressed air.
[0009]
The present invention has been made in view of the circumstances as described above, and the technical problem thereof is that the mortar falling fragments generated in the process of forming the concrete repair agent injection holes are repaired to the separation space layer. It is to prevent the inability to inject the concrete repairing agent due to blocking the agent flow path.
Another object of the present invention is to enhance the function of cooling the drill tip and discharging chips in the injection hole forming step.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a concrete wall repair method according to the present invention is a method for repairing a concrete wall with a void formed therein, and pressing the drill while rotating it obliquely against the concrete wall surface. An injection hole forming step of excavating and forming an injection hole penetrating the gap, and a repairing method in which a repair agent injection plug is attached to the injection hole and a concrete repair agent is injected into the gap communicating with the injection hole through the injection plug And an agent injection step.
[0011]
According to a more specific configuration of the repair method of the present invention, the drill is composed of a hollow drill rod and a diamond tip embedded with diamond abrasive grains formed at the tip thereof, and the diamond tip includes One or more notches extending radially are formed, water is supplied from the base side of the drill rod to the tip side thereof through the inside thereof, and the discharge and recovery of shavings from the injection hole in the process of formation are performed. This is done without using a suction mechanism .
[0012]
【Example】
FIG. 1 shows an injection hole forming process in one embodiment of the present invention, FIG. 2 shows an injection hole formed in this process, B is a concrete frame layer, A is an outer mortar outer wall layer, and C is A separation space layer D generated at the boundary between both layers A and B is an injection hole to be formed. Reference numeral 110 denotes a generally cylindrical drill rod for excavating and forming a concrete repair agent injection hole D from the outer wall surface of the mortar outer wall layer B. The root side of the rod 110 is connected to a rotation drive unit inside the drill body (not shown). It is rotated around the axis by the drive unit.
[0013]
A cutter 111 is screwed into a tip portion of a drill rod 110 that is obliquely pressed against a concrete wall to be repaired, and a diamond tip in which a roughly annular diamond abrasive is embedded in the tip surface of the cutter 111. 111a is formed. The diamond tip 111a has one or more notches extending radially outward from the center thereof. Referring to the front view of FIG. 7, the number of notches in the diamond tip is only one as shown in (A) when the diamond tip has a small diameter, but when the diameter is increased to some extent (B ) Increase to about four as shown in
[0014]
During cutting, cutting water is supplied from the root side to the tip side through the inside of the drill rod 110. The cutting water that has reached the diamond tip 111a at the tip of the cutter 111 is discharged into the injection hole D through the radial notch while cooling the diamond tip 111a that is about to become high temperature by frictional heat with the cutting surface. The The cutting water discharged into the injection hole D passes outside the injection hole through a cylindrical gap formed between the outer peripheral surface of the drill rod 110 and the inner peripheral surface of the injection hole while entraining chips generated by cutting. To be discharged.
[0015]
In this way, when the mortar outer wall layer is pressed against the normal of the wall surface while rotating the drill, the mortar outer wall layer A is cut by the diamond tip 111 a formed at the tip of the cutter 111. Along with this, the diamond tip 111a advances into the mortar outer wall layer A, and a cylindrical injection hole D inclined with respect to the mortar outer wall surface is formed by excavation. At this time, since the mortar dust and particles generated on the cutting surface are discharged to the outside of the injection hole D by the cutting water as described above, the abrasive layer is damaged by the clogging of the mortar dust and particles. In addition to being prevented, rotation is smooth and frictional heat is also efficiently dissipated.
[0016]
A part of the outer peripheral edge of the cutting surface of the injection hole D formed to be inclined with the cutting by the drill reaches the separation space layer C first. In the reaching portion, a local drop piece E from the mortar outer wall layer A is instantaneously generated by the tensile stress described above. However, after this, the end F of the cutting surface, which is at the same angle as the axial inclination angle of the drill rod 110 with respect to the upper surface of the separation space layer C, is cut so as to move along the separation space layer C. Therefore, the compressive stress generated in the mortar outer wall A by the pressing force from the diamond tip 111a acts in a direction to relieve the tensile stress generated around the compressive stress.
[0017]
Moreover, since the diamond tip 111a reaches the concrete frame layer B on the side that has previously penetrated the peeling space layer C and the pressing force from the diamond tip 111a is received by the cutting surface of the concrete frame layer B, the diamond chip 111a is peeled off. The tensile stress generated in the mortar outer wall layer A on the side that does not reach the space layer C becomes small, and the generation of falling pieces is suppressed.
[0018]
Therefore, as in the prior art, when the diamond tip 111a penetrates the separation space layer C, the conical mortar fragments are separated to form a groove-shaped opening that becomes a flow path of the concrete repair agent into the separation space layer C. The problem of blocking all around is solved. In addition, the fine fallen fragments slightly generated in the process in which the diamond chip 111a passes to the concrete frame layer B side are discharged to the outside of the injection hole by cutting water together with dust.
[0019]
FIG. 3 is a partial cross-sectional view showing a state where the injection plug 10 is inserted into the injection hole D in order to inject a concrete repair agent such as cement slurry through the injection hole formed in the concrete wall as described above. The injection plug 10 has a substantially cylindrical structure and has a backflow prevention mechanism having an appropriate structure formed inside the large-diameter portion 12 on the upper portion thereof. A cylindrical rubber packing 13, a cylindrical pressing tube 14, and a retaining ring 15 are mounted on the outer peripheral surface of the small-diameter portion 11 on the distal end side in order from the distal end side.
[0020]
When the pressing tube 14 is slid to the distal end side of the injection plug 10 using the tool 40, the packing 13 is compressed in the axial direction by the flange for retaining the distal end portion and the pressing tube 14, and expands in the radial direction. The outer peripheral surface is firmly pressed against the inner peripheral surface of the injection hole D, and the injection plug 10 is firmly fixed to the injection hole D while maintaining a liquid-tight state. In order to prevent the pressing tube 14 from returning to the base side of the injection plug 10 when the tool 40 is removed, a retaining ring 15 made of a washer with a blade is attached. This washer with a blade is formed with a plurality of blades extending in a radial direction toward the center and the base side of the injection plug 10, and a small-diameter portion whose tip is made of plastic. 11, the return of the pressing tube 14 once slid to the distal end side to the root side is prohibited.
[0021]
When the injection hole plug 10 is fixed in the injection hole D, the injection hose is connected to the base of the injection hole plug 10 through a connector having an appropriate structure, and the concrete is repaired based on the power of the pump or the manual operation. Pressurization of the agent is performed. The injected concrete repair agent passes through the inside of the injection pipe 10 and the injection hole D, and is filled into the separation space layer C. When the injection of the repair agent is completed, the connector and the hose are removed from the base side of the injection plug 10, but the repair through the injection plug 10 is performed by the backflow prevention mechanism formed inside the large-diameter portion 12 of the injection hole plug 10. The back flow of the agent is prevented.
[0022]
As described above, the groove-shaped opening of the separation space layer C on the inner wall surface of the injection hole D does not have conical mortar fragments that block the entire circumference. For this reason, even when cement slurry is used as the concrete repair agent, the cement powder in the slurry is not filtered and clogged, and the concrete repair agent injected and filled into the injection hole D is separated from the separation space layer C. Smoothly flows into and fills. Further, even if a local dropout E exists, the repair agent is diffused widely into the peeling space layer C from other portions of the groove-like opening.
[0023]
As shown in FIG. 4, the injection plug 10 is removed from the concrete wall surface using a tool 50 after the injected repair agent is solidified. That is, by using the tool 50, the pressing tube 14 is slid toward the root side of the injection plug 10 against the resistance force of the retaining ring 15. Thereby, the compression in the axial direction and the expansion in the radial direction of the packing 13 are released, and the injection plug 10 is pulled out from the injection hole D. A repair agent is filled in the hole formed by pulling out the injection plug.
[0024]
FIG. 5 is a cross-sectional view for explaining a method of injecting a concrete repairing agent into a crack C generated in the concrete frame layer B. This type of crack C often occurs inside a concrete frame layer B constructed as a soil stop. Some of these cracks are formed in the thickness direction of the concrete frame layer B and reach the boundary surface with the embankment, and the groundwater accumulated in the embankment is guided to the front through the inside of the concrete frame layer B. Let it drip. In order to prevent water leakage from the embankment through the crack C, the injection hole D reaching the crack C is formed to be inclined with respect to the wall surface.
[0025]
That is, as in the case of FIG. 1, the injection hole D is formed while supplying cutting water using a cylindrical drill rod 110 having a diamond tip 111 a formed at the tip. FIG. 6 shows the shape of the injection hole D formed as described above. According to this oblique excavation method, the groove-shaped opening of the crack C on the inner wall surface of the formed injection hole D does not have conical mortar fragments that block the entire circumference. For this reason, even when cement slurry is used as a concrete repair agent, the cement powder in the slurry is not filtered and clogged, and the concrete repair agent injected and filled into the injection hole D enters the crack C. Smoothly flows and fills. Further, even if a local dropout E exists, the repair agent is diffused widely into the crack C from the other part of the groove-like opening.
[0026]
【The invention's effect】
As described above in detail, according to the method for repairing a concrete wall according to the present invention, in the step of forming the injection hole, the drill is inclined so as to make an appropriate angle with respect to the normal line of the concrete outer wall surface, and the injection hole is inclined. Therefore, the occurrence of falling pieces from the mortar layer to the separation space layer or from the concrete frame layer to the crack at the tip of the drill is suppressed. As a result, in the subsequent step of injecting the concrete repair agent, the inflow into the separation space layer and the crack is smoothly performed without being hindered by the falling pieces. That is, even if this repair agent is a cement slurry, clogging due to cement powder filtered by the falling pieces does not occur, so that the injection is performed smoothly.
[0026]
Further, in the step of forming the injection hole, since the cutting water is supplied from the base side of the drill through the inside thereof to the diamond tip at the tip portion, the cooling of the diamond tip and the chips are reduced as compared with the case of using compressed air. Is more efficiently discharged, the diamond tip is prevented from being damaged by clogging of chips, and the rotation is smoothed, so that the process of forming the injection hole becomes extremely efficient.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a step of forming an injection hole reaching a peeling space layer formed inside a concrete wall surface using a drill bit in an embodiment of the present invention.
2 is a cross-sectional view showing an example of the shape of an injection hole formed by the forming step of FIG.
3 is a cross-sectional view showing an example of a method for fixing an injection plug in the injection hole of FIG. 2;
FIG. 4 is a cross-sectional view showing an example of a method of removing the injection hole plug from the injection hole after the injected repair agent has solidified.
FIG. 5 is a cross-sectional view showing a process of forming an injection hole reaching a crack formed inside a concrete wall surface using a drill bit in another embodiment of the present invention.
6 is a cross-sectional view showing an example of the shape of an injection hole formed by the forming step of FIG.
FIG. 7 is a front view illustrating the shape of a diamond tip forming a tip portion of a drill cutter.
FIG. 8 is a cross-sectional view showing a drilling step of forming an injection hole in a concrete wall surface with a screw-type drill bit in a conventional method.
FIG. 9 is a cross-sectional view showing a drilling step of forming an injection hole in a concrete wall surface with a core drill in a conventional method.
[Explanation of symbols]
A Mortar outer wall layer B Concrete frame layer C Separation space layer or crack D Injection hole E Local fallen debris F End of cutting surface
10 Injection plug
110 Drill rod
111 Cutter
111a diamond tip

Claims (1)

A method for repairing a concrete wall with voids inside,
An injection hole forming step of excavating and forming an injection hole penetrating through the gap by pressing a drill while rotating it obliquely with respect to the concrete wall surface;
Wherein the injection hole fitted with a repair agent injection plug in the injection plug and the injection hole and repairing agent injection process and method of repairing including concrete walls and for injecting concrete repairing agent into the interior of the gap through,
The drill is composed of a hollow drill rod and a diamond tip embedded with diamond abrasive grains formed at the tip thereof;
The diamond tip is formed with one or more notches extending radially;
Water is supplied from the base side of the drill rod to the tip side through the inside thereof;
A method for repairing a concrete wall, characterized in that discharging and collecting shavings from the injection hole in the middle of formation is performed without using a suction mechanism .

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