JPH09221768A - Structure made of concrete for underground wiring and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure, which can be mass-produced and can be provided at a low cost and requires no construction works, in which the clearance of a pit for penetrating a cable is buried. SOLUTION: A hand hole 10, in which an approximately cylindrical sleeve 20, in which the width of an inner end 21 is expanded, is buried at the penetration predetermined place of a cable in a wall 12 and which is made of concrete, is provided. Since the sleeve is made approximately the same as or slightly shorter than the thickness of the wall 12, the sleeve can be installed even at any place in forms, and the hand hole 10, in which the sleeve 20 is buried at a proper place by using forms having durability, can be manufactured. The execution of works is completed only by inserting a buried conduit pipe 3 from the outer end 22 of the sleeve 20 and fixing the conduit pipe 3 with adhesives, etc. Accordingly, construction works, in which a clearance is filled, are unnecessitated, and burying is conducted in a short time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete structure for underground wiring such as a handhole used when laying underground wiring for electric power or communication.

[0002]

2. Description of the Related Art In recent years, cables for supplying electric power,
Underground construction work is underway for communication cables, including optical fiber cables. When laying an underground burial line or branching the underground burial line from the underground burial line of the main route toward users such as factories, offices and homes in the underground line construction, concrete such as a handhole is used. Many embedded boxes are used.

On the side wall 1 of these buried boxes,
As shown in FIG. 6, a through hole 2 for a cable to pass through.
1 or a plurality of embedded electric conduits (embedded conduits) 3 made of resin such as polypropylene or vinyl chloride are installed inside the through-holes 2.
Various cables 4 are guided through the inside of the box 5 to the inside of the box 10, and are also discharged from the inside of the box to the inside of the box. The embedded conduit 3 is inserted into the through hole 2 provided in the side wall 1 of the box 10 in advance, and then the gap 6 between the buried conduit 3 and the through hole 2 is filled with a material such as mortar or epoxy.

[0004]

The tip 3a of the buried conduit 3 penetrating the wall 1 of the box is wider than other parts so that the cable 4 will not be damaged even if the cable 4 is routed inside the box. , The shape that gradually spreads into a bell mouth shape is often used. Therefore, a through hole 2 having a diameter larger than that of the buried conduit 3 is prepared for attaching a conduit having a bellmouth-shaped tip on site. After mounting, it is necessary to completely fill the gap 6 between the through hole 2 and the buried electric wire tube 3 with mortar, epoxy, or the like, which is troublesome for this work. Even when a material with good adhesion to concrete such as mortar or epoxy is used, a minute gap is likely to occur between the concrete and the buried conduit due to shrinkage, etc. Have difficulty. Furthermore, materials such as epoxy, which have good adhesion, are more expensive than concrete, which leads to an increase in construction costs. Also, even if a box such as a handhole is installed on site, the work to attach the buried conduit as described above has already been completed, and the handhole cannot be backfilled until the mortar and epoxy that fill the gap have hardened. , Is a bottleneck in shortening the construction period.

Therefore, when prefabricating the handhole, it is considered that the buried conduit is embedded in the wall in advance to shorten the construction period. However, the conditions such as the cable penetration point and the required diameter of the buried conduit are
It changes variously depending on the site and the type and amount of cables installed. On the other hand, hand holes are mass-produced using a highly durable steel mold, but in order to pre-embed the buried conduit in the form, it is necessary to open a hole through which the buried conduit passes in the mold. There is. Therefore, it is necessary to change the positions of the holes of the formwork in order to provide the buried conduits at the positions corresponding to the construction sites, and a durable formwork cannot be used. Therefore, mass productivity of the handhole cannot be maintained, and the handhole becomes very expensive.

Therefore, the present invention provides a concrete structure for underground wiring, such as a handhole, which can be mass-produced and can be provided at a low cost, and which does not require construction for filling a gap for a cable penetration hole on site. The purpose is to do. It is also an object of the present invention to provide a concrete structure for underground wiring, which can shorten the construction period at the site and can easily and completely stop water at the portion where the cable penetrates.

[0007]

Therefore, in the concrete structure for underground wiring of the present invention, a sleeve having a shape in which the inside is widened and having a width substantially equal to or slightly shorter than the wall thickness is embedded in the penetration portion of the cable, The embedded conduit can be connected to the inner surface of the sleeve from the outside of the concrete structure. That is, the concrete structure for underground wiring of the present invention has a concrete wall whose outer surface faces the underground, and the underground wiring penetrates at least one portion of this wall and is guided to the inside of the wall. There is a resin-made cylindrical sleeve of approximately the same length as the wall thickness embedded in the penetration point of the underground wiring on the wall. It is characterized by being larger than the inner diameter of the part. Such a sleeve can be installed between the outer and inner forms forming the wall, and then the concrete structure is poured by pouring concrete between these outer and inner forms. Can be manufactured. Therefore, since it is not necessary to make holes in the formwork, it is possible to mass-produce concrete products that can flexibly respond to site conditions.
Can be provided at low cost.

Further, since the inner surface portion of the wall of the embedded sleeve is widened in a bell mouth shape or the like, it is possible to prevent the cable from being damaged. Therefore, in the field,
The buried conduit can be attached to the concrete structure by simply connecting the straight conduit buried conduit to the inner peripheral surface of the sleeve from the outside of the wall. Therefore, work such as filling a gap between the buried conduit and the wall at the site is unnecessary, and the construction period can be significantly reduced. On the outer peripheral surface of the sleeve,
A female screw may be provided to attach the embedded conduit to further shorten the construction period, or the embedded conduit may be attached with an adhesive or the like.

In the concrete structure of the present invention, since the sleeve is formed integrally with the wall, no gap is generated between the sleeve and the wall, and the waterproof performance is high. Further, since the adhesion is improved by providing continuous protrusions along the circumferential direction of the sleeve on the outer peripheral surface of the sleeve, even under the condition that a minute gap is generated between the sleeve and the wall, The water can be stopped almost completely. Further, by providing this projection, the sleeve is firmly fixed to the wall, so that the sleeve will not be displaced or come off during the work such as mounting the embedded conduit.

Further, it is desirable that at least a part of the inner peripheral surface of the sleeve is provided with a protrusion protruding inward so as to serve as a stopper when the embedded conduit is fitted into the sleeve on site.

[0011]

The present invention will be further described based on the following examples. FIG. 1 shows a handhole 10 according to an embodiment of the present invention. The handhole 10 is a box type having a substantially square bottom surface, and is composed of upper and lower two units 11a and 11b, and can be constructed by assembling these units 11a and 11b on site. The upper unit 11a is a unit including four side walls 12a and a cylindrical manhole 13 for entrance and exit. Also, the lower unit 11b
Is a unit including side walls 12 b on four sides and a bottom surface 14. Further, a plurality of substantially cylindrical sleeves 20 for connecting the buried conduit tube 3 are embedded in the side wall 12b of the lower unit 11b. Of course, it is also possible to embed a sleeve in the upper unit 11a.
These units are made of concrete and are prefabricated at the factory by a durable formwork using durable members such as steel plates and transported to the site.

FIG. 2 is a sectional view showing a portion of the side wall 12 where the sleeve 20 is embedded. The sleeve 20 of this example is made of resin such as polypropylene or vinyl chloride,
The shape is substantially cylindrical, and the inner end 21 facing the inner side 10a of the handhole 10 has a bell mouth shape in which it is slightly wider than other portions. The length of the sleeve 20 is substantially equal to or slightly shorter than the thickness of the wall 12 so that the sleeve 20 does not protrude from the wall 12. An outer end 22 of the sleeve 20 facing the outer side 10b of the handhole 10 is a portion for connecting the buried conduit tube 3 with an adhesive.
The inner peripheral surface 23 of the outer end 22 of 0 is finished to be a substantially flat surface. When the embedded conduit 3 is screwed into the sleeve 20 for connection, it is desirable to form a female screw on the inner peripheral surface 23 of the outer end 22 of the sleeve 20.

On the outer peripheral surface 24 of the sleeve 20, there is formed a projection 25 continuous along the outer periphery of the sleeve 20 at a position substantially at the center of the wall 12. The protrusion 25 has a function of enhancing the adhesion between the concrete constituting the wall 12 and the sleeve 20, and prevents the groundwater from entering along the sleeve 20. At the same time, the sleeve 20 is prevented from shifting or moving with respect to the wall 12 even if a force is applied when the embedded conduit 3 is attached to the sleeve 20. To further prevent the movement of the sleeve 20, the protrusion 25 may be provided with a portion extending along the central axis direction of the sleeve 20. The protrusion 25 protruding from the outer peripheral surface 24 toward the inside of the wall 12 has a small gap between the sleeve 20 and the wall 12 even under the condition that a minute gap is generated between the sleeve 20 and the wall 12. Since it prevents the inside and outside of the wall from being connected to each other, it exerts a high water stopping ability.

The sleeve 20 of this embodiment is further provided with a stopper 27 projecting toward the inside of the sleeve 20 at approximately the center of the inner peripheral surface 23. The stopper 27 has a function of stopping the tip of the buried electric wire tube 3 at a predetermined position in the sleeve when the buried electric wire tube 3 is inserted into the sleeve 20, and thus the mounting of the buried electric wire tube 3 is simplified. Furthermore, by preventing the tip of the buried conduit tube 3 from protruding into the handhole, the cable is laid along the bellmouth-shaped inner end 21 of the sleeve 20. The stopper 27 may be provided continuously along the inner peripheral surface 23 or may be provided intermittently.

FIG. 3 shows a state in which the embedded conduit tube 3 is attached to the sleeve 20 of the handhole 10 of this example.
In the handhole 10 of this example, the outer end 22 of the sleeve 20 is
The operation of attaching the embedded conduit to the handhole is completed simply by inserting the tip of the embedded conduit 3 into the above and fixing them with an adhesive. If the embedded conduit 3 is made of a material that is difficult to fix with an adhesive such as polypropylene, the embedded conduit 3 can be attached by using a sleeve 20 having an internal thread and screwing it into the sleeve 20. Of course, it is also easy to screw the inside of the sleeve 20 in the field. Since the inner end 21 of the sleeve 20 is widened in a bell mouth shape, the buried conduit 3 is removed from the handhole 1
The electric wire 4 drawn into the inside of the sleeve 0 and the wall 12
It does not interfere with the end of the cable and is not damaged, and cable laying work can be performed easily in the handhole. The inner end 21 of the sleeve 20 does not necessarily have to be a smooth bell mouth shape as in this example, and may have a shape that prevents damage to the cable and that can be easily routed. Of course, it may be a socket-shaped one.

As described above, when the connection work of the buried conduit 3 is performed using the handhole 10 having the sleeve of this embodiment, it is only necessary to insert the buried conduit 3 into the sleeve 20, The embedded conduit 3 and the sleeve 20 can be brought into close contact with each other with an adhesive or the like. The same applies when these are screwed in, and a seal tape or the like can be used to further improve the adhesion. For this reason, when the construction is performed using the handhole 10 of this example, it is not necessary to fill the gap between the buried conduit and the handhole with mortar or epoxy. Therefore, the construction cost is low, the construction period is short, and the product can be backfilled immediately. In particular, it is possible to easily construct buried conduits even at sites with high groundwater levels. In the handhole 10 of this example, the sleeve 2
0 and the buried conduit 3 have high adhesion, and further, the sleeve 20 and the wall 12 also have high adhesion, so that the waterproof performance around the buried conduit 3 is very high. Thus, by adopting the handhole 10 including the sleeve of this example,
Inexpensive underground wiring work such as undergrounding of electric wires,
And it can be done in a short period of time.

4 and 5, the handhole 1 of this example is shown.
The outline of manufacturing 0 using a mold is shown. The handhole 10 of this example is manufactured in a factory using a durable outer mold 31 and an inner mold 32 made of steel or the like. When manufacturing the handhole 10 of this example, the sleeve 20 having the above-described configuration is installed between the outer mold 31 and the inner mold 32 at a position where the side wall 12 is supposed to pass through the cable. Concrete 35 is poured between the outer mold 31 and the inner mold 32. Since the sleeve 20 of this example is approximately equal to or slightly shorter than the thickness of the wall 12, it can be installed without making holes in the outer mold 31 and the inner mold 32. Therefore, anywhere on the wall 12 of the handhole,
Any number of sleeves can be provided, and the position thereof can be freely changed. In this way, the handhole of this example can be mass-produced by using the durable formwork that manufactures the handhole of a predetermined shape, and by providing the cable penetration portion at the position desired by the builder. In addition to that, it is possible to inexpensively manufacture a product corresponding to each site. The sleeve 20 may be fixed by being sandwiched between the outer formwork 31 and the inner formwork 32 so as to be located at a position corresponding to the penetration position of the cable, or a core material such as styrene foam may be inserted into the sleeve 20. The core material may be fixed by being sandwiched between the outer mold 31 and the inner mold 32. It is also possible to attach the sleeve 20 to the form using an adhesive tape or magnetic force.

As described above, the handhole 10 provided with the sleeve 20 of this embodiment is excellent in mass productivity, and the sleeve for penetration can be installed at any position corresponding to the penetration position of the cable. In addition, this sleeve
Since there is no portion protruding from the handhole 10, it does not hinder transportation, and the buried conduit can be easily connected at the site as described above.

Although the present invention has been described by taking a handhole as an example in this example, the present invention is not limited to a handhole, and concrete that can be extended in the direction of embedding a cable having a U-shaped cross section. Needless to say, it can be applied to all unitized concrete structures that process underground wiring, such as manufactured underground wiring boxes.
Further, not only the side wall as in the above example, but also the bottom of a concrete structure or other direction bulkhead cable can be pulled in, the sleeve similar to the above can be used.

[0020]

As described above, in the concrete structure such as the handhole of the present invention, a sleeve having a thickness equal to or slightly shorter than the thickness of the wall which is widened inward is embedded in the penetration portion of the cable. A buried conduit can be connected to the inner surface of the sleeve from the outside of the concrete structure. Therefore, the work of filling mortar or the like in the gap between the buried conduit and the wall is unnecessary, the work on the site can be completed in a short period of time, and the construction cost can be reduced. Further, in the concrete structure of the present invention, the position where the sleeve is provided can be freely adjusted, and the cable penetration point can be changed without changing the formwork for manufacturing the concrete structure. Therefore, it is possible to provide a concrete structure for underground wiring that can flexibly respond to site conditions and can be inexpensively supplied.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a handhole according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a portion of the handhole shown in FIG. 1 in which a sleeve is embedded.

FIG. 3 is a cross-sectional view showing a state in which a buried conduit is constructed using the sleeve shown in FIG.

FIG. 4 is a diagram showing a state of manufacturing the handhole shown in FIG. 1, and a state of installing a sleeve between an outer mold and an inner mold.

5 is a diagram showing a state where concrete is poured between the outer mold and the inner mold shown in FIG.

FIG. 6 is a cross-sectional view showing a state in which a buried conduit is installed in a conventional handhole.

[Explanation of symbols]

 3 ・ ・ Buried conduit 4 ・ ・ Cable 5 ・ ・ Underground 10 ・ ・ Hand hole 11 ・ ・ Upper / lower unit 12 ・ ・ Sidewall 20 ・ ・ Sleeve 21 ・ ・ Sleeve inner end 22 ・ ・ Sleeve outer end 23 ・・ Inner surface of sleeve 24 ・ ・ Outer surface of sleeve 25 ・ ・ Protrusions protruding from the sleeve 27 ・ ・ Stoppers protruding to the inside of the sleeve 31 ・ ・ Outer mold 32 ・ ・ Inner mold

Claims (5)

[Claims] 1. A concrete structure for underground wiring, which has a concrete wall whose outer surface faces the ground, and through which underground wiring penetrates at least one location of the wall and is guided to the inside of the wall, A cylindrical sleeve made of resin and having a length substantially equal to the thickness of the wall is embedded in a portion of the wall where the underground wiring penetrates, and the inner surface side of the sleeve is wider than other portions. A concrete structure for underground wiring, which is characterized in that 2. The concrete structure for underground wiring according to claim 1, wherein a portion of the sleeve on the inner surface side of the wall has a bellmouth shape. 3. The concrete structure for underground wiring according to claim 1, wherein a continuous protrusion is formed on an outer peripheral surface of the sleeve along a circumferential direction of the sleeve. 4. The concrete structure for underground wiring according to claim 1, wherein a protrusion protruding inward from at least a part of an inner peripheral surface of the sleeve is formed. 5. A method for manufacturing a concrete structure for underground wiring, which has a concrete wall facing the ground, and underground wiring penetrates at least one portion of the wall and is guided to the inside of the wall. An outer mold for forming the wall, which is formed of a resin and has a bellmouth shape at one end, which is made of resin and has substantially the same length as the thickness of the wall at a position where the underground wiring is to be penetrated through the wall. A method of manufacturing a concrete structure for underground wiring, which is installed between a frame and an inner formwork, and concrete is injected between the outer formwork and the inner formwork.