JP2949271B2 - Underground cable laying method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to underground cable laying using a perforated pipe block for laying underground cables for power and communication, such as electric wires, telephone lines, and optical fibers. About the method.

[0002]

2. Description of the Related Art Conventionally, there is a so-called common groove method as an underground method for cables for electric power and communication. In this method, cables such as electric wires are housed in the underground ditch together with gas pipes and water pipes. However, the conventional joint ditch method requires high construction costs and long-term construction, so it quickly responds to the information society. There was a problem that it was almost impossible to do.

[0003] For this reason, in recent years, a so-called cab system (abbreviation of cable box network system) in which a box for accommodating cables is buried in the ground and cables are inserted therethrough has been promoted.

[0004] In general, a cab system is constructed by using a cast-in-place concrete or a concrete block to construct a U-shaped groove-shaped underground groove and closing the upper part with a lid. As shown in FIG. 8, a plurality of cable insertion holes 1 and 1
As shown in FIG. 10, ceramic porous tubes 2, 2,... Having openings 1 are continuously buried between relay hand holes 10, 10,.

As shown in FIG. 9, each handle hole 10 is formed to have a size necessary for cable insertion work, and the upper portion is closed by a lid 11 so as to be openable.

These are installed at intervals of 20 to 50 m, and the spaces therebetween are communicated by the above-described ceramic porous tubes 2, 2,..., And the cable insertion holes 1, 1,. , And the branch cable insertion pipes 50, 50 from the handhole 10 as shown in FIG.
, The branch cable is led into each building 100, 100,....

Although not shown in the drawings, an underground method in which a steel pipe or a synthetic resin pipe is buried between hand holes instead of the above-described perforated pipe has been developed.

[0008]

In the cable underground method using a conventional perforated pipe as described above, since the perforated pipe is made of porcelain, it is not possible to form a branch hole after firing, and therefore, a handhole is required. The branch cable can be led out only from the part or the branch pipe part where the branch hole has been formed and fired in advance, and even when using a steel pipe or a synthetic resin pipe, the branch hole can be drilled when laying. However, there is a possibility that the cable passed inside may be damaged after laying, so that a branch hole cannot be formed, and in any case, the branch cable can only be led out from the handhole after laying.

For this reason, when it is necessary to derive a branch cable to a new building after laying the cable, if the building is far from the handhole, it is necessary to route a long branch cable, which leads to an increase in construction cost and construction period. And the traffic obstruction becomes longer.

[0010] The present invention has been made in view of such conventional problems, only <br/> Oh the branch hole in a substantially arbitrary position even after underground laying of cables can be suitably derived without damaging the branch cable The purpose of the present invention is to provide a cable underground laying method that can reduce the scale of cable drawing work to a new building.

[0011]

A cable according to the present invention for solving the conventional problems as described above and achieving the intended object.
The characteristic of the underground laying method is that cables for power and communications
Equipped with multiple cable insertion holes to be inserted in the longitudinal direction
A block main body, and the cable on a side surface of the block main body.
The cable insertion hole at the position corresponding to the cable insertion hole.
And a recess for a branch hole having a depth of
Many with thin walls that can be broken between bull insertion holes
Cable for underground laying perforated pipe block for each cable
Align the insertion holes with each other and make them continuous in the longitudinal direction.
Insert the main cable into each cable insertion hole.
And appropriate branching of the perforated tube block
Break and remove the thin wall in the hole recess to open the branch hole
And a cylindrical joint whose tip is expanded into the branch hole
Into the branch hole, and fix it.
And connect the branch cable insertion tube to the joint.
Through the joint and the branch cable insertion tube.
To derive the table .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS.

In the figure, reference numeral 20 denotes a perforated tube block,
As shown in FIG. 1 to FIG. 3, it is composed of a block main body formed of reinforced concrete into a rectangular parallelepiped having a length of about 1 m. The front and rear end surfaces of the block body are provided with mutually corresponding convex and concave fitting portions 28 and 29.

A plurality of cable insertion holes 22, 22,... Are arranged vertically, horizontally, and through the front end face to the rear end face inside the block body. The cable insertion hole 22 is formed in a cylindrical shape having a sufficient cross-sectional area for accommodating the main cable, and therefore the cross-sectional area of the block body is extremely small. Although the figure shows a block body having six cable insertion holes 22, the number of cable insertion holes 22 may be two, four, or the like according to the number of cables to be accommodated.

A plurality of branch hole recesses 24, 24... Are formed on both side surfaces of the block body.
The branch hole recess 24 is formed in a tapered cylindrical shape having a cross-sectional area similar to that of the cable insertion hole 22 and is formed at a depth that does not reach the cable insertion hole. . As a result, a thin wall 23 is formed between each cable insertion hole 22 and each branch hole recess 24. When the thin wall 23 is hit with a hammer or the like, the thin wall 23 is crushed and the cable insertion hole 22 and the branch hole are formed. A branch hole communicates and opens between the concave portions 24.

The porous tube block 20 constructed as described above
As shown in FIG. 4, a plurality of relay handholes 10, which are buried at a distance of 20 to 50 m, are connected in a longitudinal direction so as to communicate between the handholes 10, 10. Buried in In addition, handhole 10 and building 1
Between 00 and 00, the branch cable insertion tube 50 is embedded. In addition, the handhole 10 is formed in a box shape of a size necessary for the insertion work of the cables, similarly to the one shown in FIG.
The upper part is closed by a lid 11 so as to be openable, and the embedded state is the same. The embedded state of the perforated tube block 20 is the same as that of the perforated tube 2 shown in FIG.

In burying the perforated pipe blocks 20, 20,..., The cross-sectional area of the block body is minimized, so that the excavation (opening) range for burying is small, and the construction cost and construction period are reduced. Can be. The porous tube blocks 20, 20,... Are connected in such a state that rubber packing is sandwiched between the end faces of the front and rear block bodies, the fitting portions 28, 29 are fitted, and the cable insertion holes 22 are aligned with each other. so,
It is performed by tightening via bolts and nuts.

The main cable is inserted into each cable insertion hole 22 of the perforated pipe block 20, and the branch cable is inserted through the branch cable insertion pipe 50. Note that it is not always necessary to provide the branch hole concave portions in all the porous tube blocks. For example, a porous tube block having a branch hole concave portion and a porous tube block having no branch hole concave portion are alternately connected. And may be buried.

Thus, the perforated tube blocks 20, 2
After the burial of the handholes 10 and 10 and the underground laying of the cables are completed, if it becomes necessary to lead the cables to the new building 101, first, the building 1
The vicinity of the branch hole concave portion 24 of the porous tube block 20 which is the shortest distance from 01 is dug back. Then, the concave portion 24 for branch holes
The thin wall 23 inside is hit with a hammer or the like to be crushed and removed, and a branch hole is opened in a part of the side surface of the perforated pipe block 20 to allow the cable insertion hole 22 to communicate with the branch recess 24. In addition, since the porous tube block 20 is made of reinforced concrete, only the thin wall 23 can be suitably crushed and removed, and there is no possibility that other portions are destroyed as in the case of ceramic.

Then, as shown in FIGS. 5 and 6, a joint 40 is fixed to the side surface of the perforated tube block 20 so that the front end is inserted into the communication hole and the rear end is projected outward. The branch cable insertion pipe 51 is connected to the pipe joint 45 fixed to the rear end of the cable. As shown in FIG. 4, the branch cable insertion pipe 51 is buried between the building 101 and the branch cable insertion pipe 51. Therefore, since it is only necessary to dig the shortest distance perforated pipe block 20 from the building 101, the excavation area for burying the branch cable insertion pipe 51 is small, and the scale of the work for drawing the cable into the new building 101 is reduced. can do.

The joint 40 connecting the perforated tube block 20 and the branch cable insertion tube 51 is made of resin,
As shown in FIGS. 5 and 6, the distal end 43 is formed in a bell-shaped cylindrical shape with an expanded end, and the distal end 43 has an outer diameter of the cable insertion hole 22 so as not to protrude toward the cable insertion hole 22. Are formed in an arc shape corresponding to. Accordingly, since the branch cable inserted into the joint 40 does not contact the crushed surface of the branch hole, the branch cable can be suitably led out without damaging the branch cable, and the joint 40 becomes an obstacle to the insertion of the main cable. Nor. Further, the joint 40 has a flange 41 that can cover the branch hole concave portion 24. The joint 40 is fixed to the side surface of the perforated pipe block 20 with an adhesive through the flange 41, and the branch is formed. The hole is closed and water is stopped. The pipe joint 45 attached to the rear end of the joint 40 is formed in a cylindrical shape having a tapered portion, and is replaceable according to the pipe diameter of the branch cable insertion pipe 51.

When connecting the branch cable insertion tube 51 obliquely to the perforated tube block 20, a joint 140 as shown in FIG. 7 can be used. Since the joint 140 is the same as the joint 40, corresponding portions are denoted by the same reference numerals and description thereof will be omitted. Also,
Although the joints 40 and 140 are made of resin, they may be made of casting or may be fixed by bolts and nuts.

[0023]

As described above, the cable underground laying method according to the present invention has a block main body provided with a plurality of cable insertion holes for inserting power and communication cables in the longitudinal direction. A branch hole recess having a depth that does not reach the cable insertion hole is provided at a position corresponding to the cable insertion hole on the side surface of the main body, and a thin wall that can be broken between the branch hole recess and the cable insertion hole is provided. A large number of cable underground laid porous pipe blocks are buried in the ground so that the cable insertion holes are aligned with each other and are continuous in the longitudinal direction, and the main line cable is inserted into each of the cable insertion holes, as appropriate. wherein an appropriate thin wall of the branch hole for the recess of the porous tube blocks disrupted by removing by communication opening the branch hole, by deriving a branch cable from the branch hole, underground laying of cables If the retraction of the cable to a new building becomes necessary in so the branch cable may be laid in the shortest distance, it is possible to reduce the construction size Rutotomoni, minute岐孔recess for The thin wall is removed, a cylindrical joint having an expanded end is inserted and fixed in the branch hole communicated with the cable insertion hole, and the rear end is drawn out from the branch hole, and the branch cable is inserted into the joint. By connecting the pipes, the branch cable can be suitably led out without being damaged, and does not hinder the insertion of the main cable.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of an embodiment of a perforated pipe block for cable underground laying according to the present invention.

FIG. 2 is a cross-sectional view taken along line AA in FIG.

FIG. 3 is a longitudinal sectional view taken along line BB in FIG.

FIG. 4 is a view showing an example of an embodiment of a cable underground laying method according to the present invention, and is a plan layout view of a perforated pipe block, a handhole, and a branch cable insertion pipe.

FIG. 5 is a view showing an example of a joint, and is a cross-sectional view showing a state where the joint is mounted on a perforated tube block.

6 is a longitudinal sectional view taken along the line CC in FIG.

FIG. 7 is a view showing another example of the joint, and is a longitudinal sectional view showing a state where the joint is mounted on a perforated tube block.

FIG. 8 is a cross-sectional view showing an example of a conventional perforated tube block, which is buried under a sidewalk.

FIG. 9 is a cross-sectional view showing an example of a handhole, showing a state where the handhole is buried under a sidewalk.

FIG. 10 is a view showing an example of a conventional cable underground laying method, and is a plan layout view of a perforated pipe block, a handhole, and a branch cable insertion pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hand hole 11 Lid 20 Perforated pipe block 22 Cable insertion hole 23 Thin wall 24 Depression for branch hole 28, 29 Fitting part 40, 140 Joint 41 Flange 43 Tip 45 Pipe joint 50, 51 Branch cable insertion pipe 100, 101 Building

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E02B 9/06 E02F 5/10 E03F 3/04 F16L 1/038

Claims (1)

(57) [Claims] 1. A cable for inserting a power or communication cable.
Block body with multiple bull insertion holes facing the longitudinal direction
Having the cable insertion hole on the side surface of the block main body.
Depth of the depth that does not reach the cable insertion hole at the corresponding position
A recess for a branch hole is provided, and between the recess for the branch hole and the cable insertion hole.
Cables with thin walls that can be broken
Insert the insulated perforated pipe block into each cable insertion hole
Buried in the ground continuously in the longitudinal direction aligned with the
Insert the main cable into each cable insertion hole.
In the appropriate branch hole recess of the appropriate porous tube block
The thin wall is broken and removed to open the branch hole.
Insert a cylindrical joint with an expanded tip into the branch hole
And fix the rear end from the inside of the branch hole.
Connect the branch cable insertion tube to the
Of branch cable through the inside of branch and branch cable insertion tube
Underground cable laying method characterized by the following.