JP3378403B2 - Reinforcement and repair method of asbestos cement pipe - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing and repairing asbestos cement pipes used for water pipes and the like.

[0002]

2. Description of the Related Art Asbestos-cement pipes are lightweight, easy to process and inexpensive, but have a lower strength than iron pipes and are more susceptible to breakage. Especially after many years of installation,
It may be eroded by soil, groundwater, etc., and the thickness of the pipe may be reduced, resulting in a significant decrease in strength.

In this case, when the asbestos cement pipe buried due to road surface vibration or gas or water works is dug out, the fragile portion is broken and causes a flood accident.

In order to prevent such an accident, it is necessary to reinforce the fragile portion of the pipe body. Therefore, conventionally, when a fragile portion is found in the asbestos cement pipe, one straight pipe is laid. The pipes are replaced or replaced with other types of tough pipes.In that case, the buried part of the pipes must be excavated extensively and new pipes must be arranged. If it is carried out, the construction will be large-scaled, and many man-hours and construction periods will be required, and the construction cost will increase.

Therefore, there is a construction method in which the existing asbestos cement pipe is used as it is, and the fragile portion of the asbestos cement pipe or the branch pipe construction site and further only the vicinity of the valve installation site are reinforced.

This construction method is, for example, as shown in FIG.
As shown in Japanese Patent No. 5919, the asbestos-cement pipe 01 is dug up around the place where the branch pipe construction is to be performed to form an excavation moat A, and the asbestos-cement pipe 01 is covered with a metal auxiliary dividing pipe 02 to asbestos. The space between the cement pipe 01 and the auxiliary metal split pipe 02 is filled with a filler such as concrete milk or epoxy resin.

[0007]

However, since the asbestos-cement pipe 01 is generally eroded and weakened due to secular change, a large excavation moat A as shown in the figure is dug,
When the asbestos-cement pipe 01 is exposed, the asbestos-cement pipe 01 is easily broken due to the weight of the metal auxiliary split pipe 02 and the filler 03.

Further, the metal auxiliary division pipe 02 has a large weight for securing strength, and the asbestos cement pipe 0 is not provided in the excavation moat A.
A large number of workers are required for the work of installing the auxiliary split pipe 02 below 1, which complicates the work.

It is an object of the present invention to provide a strong asbestos-cement pipe covering pipe that does not use a material having a large specific gravity such as a metal pipe when reinforcing or repairing an asbestos-cement pipe.

[0010]

In order to solve the above problems, the asbestos cement pipe reinforcement and restoration method of the present invention is a method for reinforcing or restoring an existing asbestos cement pipe,
A high strength concrete is applied to the outer peripheral surface of an asbestos cement pipe to form a high strength concrete layer, and then the outer peripheral surface of the high strength concrete layer is covered with at least a two-piece plastic covering pipe. There is.

In the asbestos-cement pipe reinforcement and restoration method of the present invention, it is preferable that a plurality of projections having a length equal to or greater than the wall thickness of the high-strength concrete layer are formed on the inner surface of the plastic covering pipe. .

In the asbestos cement pipe reinforcement and restoration method of the present invention, it is preferable that the covering pipe is a fiber reinforced plastic.

In the method for reinforcing and restoring the asbestos-cement pipe of the present invention, it is preferable that the high-strength concrete is made by mixing semi-pyroxene garnet, synthetic resin or the like into cement.

[0014]

[Function] By applying high strength concrete to the outer peripheral surface of the asbestos cement pipe to form a high strength concrete layer, the asbestos cement pipe is reinforced and restored. Since this high-strength concrete layer is thin and lightweight, it can strongly support a fragile asbestos cement pipe without burdening it. Further, since the plastic coating pipe is applied after the high-strength concrete is applied, it is possible to backfill without completely curing it, and since the concrete is not exposed in the soil, deterioration of the pipe can be prevented.

By forming a plurality of projections having a length equal to or greater than the wall thickness of the high-strength concrete layer on the inner surface of the plastic cladding tube, the cladding tube can be formed without waiting for drying and hardening of the high-strength concrete. Since it can be installed, the construction period is shortened.

When a fiber reinforced plastic pipe is used as the covering pipe, the fiber reinforced plastic has the same strength as or higher than that of the asbestos cement pipe, and therefore, in combination with the strength of the high strength plastic, The strength can be increased.

By using semi-pyroxene garnet and cement mixed with synthetic resin as the high-strength concrete layer, strong reinforcement can be achieved with a thin concrete layer.

[0018]

Embodiments of the present invention will now be described with reference to the drawings. First Embodiment FIGS. 1 and 2 show the first embodiment of the present invention.
Is an asbestos cement pipe (AC) made of Portland cement and asbestos fiber (asbestos), and is normally buried in the ground as an existing water pipe. This asbestos cement pipe 1
As mentioned above, since it has been eroded and weakened due to aging, it is necessary to reinforce the fragile part, take out a branch pipe from this asbestos cement pipe, and install an on-off valve, a switching valve, etc. Done. Therefore, in order to perform these reinforcements, repairs, and even waterworks, an excavation trench for construction is dug around it, and the asbestos-cement pipe 1 is locally and temporarily exposed.

Next, high-strength concrete used as a reinforcing and repairing material for concrete is applied to a predetermined position on the outer peripheral surface of the asbestos-cement pipe 1 at a predetermined thickness, for example, to a total thickness of the exposed outer peripheral surface. The outer periphery is covered with a high strength concrete layer 7. This high-strength concrete includes, for example, semi-pyroxene garnet mixed with synthetic resin and cement, and the bending strength is 5 times or more as compared with the current method of overcoating cement, and acrylic resin aqueous solution, etc. By being mixed, the adhesiveness with the asbestos cement pipe 1 is extremely high.

Reference numeral 2 is a covering pipe made of plastic, and is composed of divided covering pipes 2 ', 2'which are divided into two parts so that the asbestos cement pipe 1 can be crowned vertically or horizontally. It should be noted that although it is divided into two in this embodiment, it may be divided into three and four according to the diameter of the asbestos cement pipe.

These divided coating tubes 2 ′ can be polymerized and bonded without continuously forming a protrusion such as a flange for continuously connecting the coating tube 2, and the coating tube completed before the coating. In order to be able to polymerize and adhere to one outer peripheral portion of the outer peripheral portion of 2, the superposed pieces 3 and 4 having an inner diameter larger than the inner diameter of the divided covering tube 2 ′ by the thickness of the divided covering tube 2 ′ are provided in a protruding manner. The polymerized piece 3 has a function of widely taking an adhesive portion, and is extremely effective for joining the divided covering tubes 2 '.

The split cladding tube 2'in the present invention is, for example, one operator who splits the split cladding tube 2'from below the excavation pit.
The other person lowers the divided covering tube 2 ′ from above and presses the surface of the adhesive resin 6 appropriately coated with the adhesive resin onto the surface of the other adhesive resin to easily and sequentially asbestos. The coating pipe 2 can be coated on the cement pipe 1.

Here, 5 is a screw or a rivet for connecting the two divided covering pieces 2 ', 2'using the facing overlapping piece 3 when the bonding strength is insufficient with only the adhesive.

Further, in this embodiment, the outer diameter of the asbestos-cement pipe 1 and the inner diameter of the covering pipe 2 are substantially the same, considering the thickness of the high-strength concrete layer 7, and allowing a slight allowance. As shown in FIG. 2, the inner surface of the covering pipe 2 is close to or in contact with the outer peripheral surface of the high-strength concrete layer 7 so that the covering can be integrally covered.

FIG. 3 and FIG. 4 show a second embodiment of the present invention, which is different from the first embodiment in that at least an appropriate portion of the inner peripheral surface of the divided covering tube 2 ′ located at the upper portion is at least elevated. Protrusion 10 having a length equal to or greater than the thickness of the strength concrete layer 7
That is, a plurality of points are formed. The protrusion 10 can be easily cut with a file or the like, and the alignment of the asbestos cement pipe 1 and the covering pipe 2 can be easily adjusted at the construction site.

Further, since these projections 10 have at least a length equal to or greater than the wall thickness of the high-strength concrete layer 7,
For example, even if the upper and lower split covering pipes 2'are attached to the outer peripheral surface of the high-strength concrete layer 7 while the high-strength concrete layer 7 applied to the outer peripheral surface of the asbestos-cement pipe 1 is not completely cured, A space in which the high-strength concrete layer 7 having a predetermined thickness is formed is ensured on the inner peripheral surface of 1 and the entire outer peripheral surface of the asbestos-cement pipe 1. Therefore, after applying the high-strength concrete, the outer surface of the high-strength concrete layer 7 is covered with the covering pipe 2 without waiting for the drying and hardening of the high-strength concrete.
Since it can be covered with, the construction period can be shortened.

As described above, in the present invention, the asbestos cement pipe 1 is used.
By applying high-strength concrete to the outer peripheral surface of and the high-strength concrete layer 7 is formed, the fragile asbestos-cement pipe 1 is reinforced. The high strength concrete layer 7
Since the whole is thin and lightweight, the weight burden on the asbestos cement pipe 1 is extremely reduced, and since it is the same concrete, the compatibility with the asbestos cement pipe 1 is good.

Furthermore, by covering the outer peripheral surface of the high-strength concrete layer 7 with the covering pipe 2, the reinforced asbestos cement pipe 1 can be backfilled early without waiting for the hardening time of the high-strength concrete to elapse. it can. In addition, since the surface of the high-strength concrete layer 7 is protected without being exposed in the soil even when the asbestos-cement pipe 1 is backfilled in the soil, deterioration of the concrete is more effectively prevented. Also, since the cladding tube 2 is made of lightweight plastic,
The weight load on the asbestos cement pipe 1 and the work load are reduced.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and even if there are changes and additions within the scope not departing from the gist of the present invention, the present invention is not limited. Included in the invention.

For example, various constituent materials of high-strength concrete are optional and are not limited to those of the embodiment. Further, when the covering pipe 2 is made of reinforced fiber plastic, it works together with the high-strength concrete layer 7 to further increase the reinforcing strength.

[0031]

As described above, the present invention has the following effects.

(A) The asbestos cement pipe is reinforced and restored by applying high strength concrete to the outer peripheral surface of the asbestos cement pipe to form a high strength concrete layer. Since this high-strength concrete layer is thin and lightweight, it can strongly support a fragile asbestos cement pipe without burdening it. Further, since the plastic coating pipe is applied after the high-strength concrete is applied, it is possible to backfill without completely curing it, and since the concrete is not exposed in the soil, deterioration of the pipe can be prevented.

(B) On the inner surface of the plastic cladding tube,
By forming a plurality of protrusions having a length at least equal to the wall thickness of the high-strength concrete layer, it is possible to install the cladding tube without waiting for the high-strength concrete to dry and harden, which shortens the construction period. It

(C) When a fiber reinforced plastic pipe is used as the cladding pipe, the fiber reinforced plastic has the same strength as or higher than that of the asbestos cement pipe, so that the asbestos is more effective in combination with the strength of the high strength plastic. The strength of the cement pipe can be increased.

(D) By using semi-pyroxene garnet and cement mixed with synthetic resin as the high-strength concrete layer, strong reinforcement can be achieved with a thin concrete layer.

[0036]

[Brief description of drawings]

FIG. 1 is a process drawing of an asbestos cement pipe reinforcing process according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view of essential parts of a second embodiment of the present invention.

FIG. 4 is a sectional view of a second embodiment corresponding to FIG.

FIG. 5 is a partial cross-sectional view of a conventional asbestos-cement pipe during reinforcement.

[Explanation of symbols]

1 asbestos cement pipe 2 cladding 2'split cladding 3 polymer pieces 4 polymerized pieces 5 screws or rivets 6 Adhesive resin agent 7 High-strength concrete layer 10 protrusions

Front page continuation (72) Inventor Ryoichi Ishida No. 701, 2-16-1, Shimbashi, Minato-ku, Tokyo Room No. 706, New Shimbashi Building Cosmo Koki Co., Ltd. (72) Inventor Toshio Saito 2283 Sakahama, Inagi, Tokyo Within Super Resin Industry Co., Ltd. (56) References: Showa 63-109524 (JP, U) Showa 52-14704 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16L 1/024 F16L 58/06 F16L 58/10

Claims (4)

(57) [Claims] 1. A method for reinforcing or repairing an existing asbestos cement pipe, wherein high strength concrete is applied to the outer peripheral surface of the asbestos cement pipe to form a high strength concrete layer,
Next, a method for reinforcing and repairing an asbestos cement pipe, characterized in that the outer peripheral surface of the high-strength concrete layer is covered with a plastic covering pipe divided into at least two parts. 2. A method for reinforcing and repairing an asbestos-cement pipe according to claim 1, wherein a plurality of protrusions having a length of at least the wall thickness of the high-strength concrete layer are formed on the inner surface of the plastic covering pipe. . 3. The method for reinforcing and restoring asbestos cement pipe according to claim 1, wherein the covering pipe is fiber reinforced plastic. 4. The method for reinforcing and restoring asbestos-cement pipe according to claim 1, wherein the high-strength concrete is cement mixed with semi-pyroxene garnet, synthetic resin and the like.