JP2013150445A - Conduit section of wire common duct and installation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent floating of the conduit section of a wire common duct due to liquefaction phenomenon.SOLUTION: Sand or improved soil 4 is placed around a conduit 3, the conduit and crushed rock or sand are held by a sheet 2 through which water permeates but sand does not permeate, and the sheet is connected to a bottom plate 4 under the conduit. With such a structure, irregular floating of the conduit due to liquefaction phenomenon can be prevented by the weight of the bottom plate. Furthermore, liquefied muddy water can preferably be released to upper part, when the periphery of the sheet is filled with a material 7 of high water permeability such as crushed rock.

Description

  The present invention relates to a conduit portion of an electric wire joint groove for wiring various electric wires such as a power line, a telephone line, a communication line, and an optical cable underground, and an installation structure thereof.

In the recent promotion plan for non-electric poles, various types of electric wires are collectively accommodated in an electric wire common groove (commonly known as CC Box), and the electric wire common groove is buried underground such as a main road. The utility pole is being planned. Such an electric wire joint groove is provided with a buried pipe section and a special section for maintenance management at regular intervals of the pipe section.
On the other hand, when the ground is liquefied by an earthquake, it is well known that buoyancy acts on the manhole and the upper part jumps out onto the road surface.
However, in reality, not only manholes, but also special parts of the cable common groove may rise, and pipes that have been placed in the ground over long distances may rise irregularly, resulting in cutting in the middle. There is a risk of damage to the extent that it cannot be put to practical use.

  In order to prevent the levitation of the pipe line due to such a liquefaction phenomenon, for example, on both sides of the underground buried pipe, a pair of bored holes sandwiching the buried pipe is provided with a hard layer below the ground where the buried pipe is buried. After drilling holes at regular intervals across the ground, jet grouting from the borehole around the buried pipe to form a jet grouting band of hardened material between the paired boreholes, then steel wire or steel in the borehole A floating prevention method characterized by inserting a steel rod is known (see Patent Document 1).

JP-A-7-286356

According to such a levitation prevention method, it is possible to prevent the levitation of the pipe line due to the liquefaction phenomenon, but it is too costly, and there are a plurality of relatively thin electric pipes in the pipe joint portion of the electric wire joint groove. Since there is a need for road expansion and branch construction, a method of fixing the pipe line by jet grouting around the buried pipe is not suitable.
Accordingly, an object of the present invention is to easily and effectively prevent the floating of the pipe portion of the common wire groove due to the liquefaction phenomenon without the above-mentioned problems.

  In view of such circumstances, the present inventor has conducted intensive research, and as a result, placed sand or improved soil around the pipe line, and the pipe line and the sand or the improved soil are permeable to the sand. The present invention has been completed by finding that it is possible to easily and effectively prevent irregular floating of a pipe line due to a liquefaction phenomenon by gripping with a non-penetrating sheet and connecting the sheet to a bottom plate as a weight.

  That is, the present invention arranges sand or improved soil around a pipe line, grips the pipe line and the sand or the improved soil with a sheet that is permeable but not permeable to earth and sand, and the sheet. Is connected to the bottom plate under the pipe, and provides a pipe part of the common wire groove.

Moreover, this invention provides the pipe line part of the said electric wire joint groove characterized by the said sheet | seat being further reinforced with the reinforcing material.
Moreover, this invention provides the pipe line part of the said electric wire joint groove whose said baseplate is a product made from precast concrete.
Furthermore, the said baseplate provides the pipe line part of the said electric wire joint groove | channel which has a drainage path of an up-down direction.
Furthermore, the present invention provides a pipe section of the above-mentioned electric wire joint groove characterized in that a part of a sheet reinforced with a reinforcing material and having water permeability but not penetrating earth and sand is embedded in a bottom plate. Is.
Furthermore, the present invention provides a material having high water permeability at the bottom of the groove, and provides a pipe section of any one of the above-mentioned electric wire joint grooves on the material, and further, a gap between the groove and the pipe section. And the installation structure of the pipe line part of the common wire groove | channel characterized by providing material with high water permeability on this pipe line part.

  According to the present invention, it is possible to easily and effectively prevent floating due to the liquefaction phenomenon of the pipe portion of the common wire groove, in particular, irregular rise for each pipe line.

It is a schematic longitudinal cross-sectional view of the pipe line part of an electric wire joint groove. It is the schematic longitudinal cross-sectional view which expanded a part of connection location of the special part main body and conduit part of an electric wire joint groove.

  Preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings, but the present invention is not limited thereto.

Embodiments will be described below with reference to the drawings.
FIG. 1 shows an embodiment of the conduit portion of the common wire groove according to the present invention.
As shown in FIG. 1, in the present invention, a sand or improved soil 4 is disposed around a pipe line 3, and the pipe 2 and the sand or improved soil 4 are permeable to water but do not pass through the earth and sand. And the sheet is connected to the bottom plate 1 below the pipe line.
With this configuration, the present invention mainly prevents the floating of the pipeline by the weight of the bottom plate, and prevents the irregular rise of the pipeline with the sheet.

The bottom plate 1 used in the present invention prevents the floating of the pipe line due to the liquefaction phenomenon due to its weight, and preferably has a large specific gravity. Preferred examples of the bottom plate include concrete, iron, stone, and the like, but precast concrete is particularly preferable in consideration of cost and convenience. Moreover, the bottom plate may have a drainage channel for allowing the liquefied mud water to escape upward.
In the present invention, the specific gravity of the bottom plate, the sheet that has water permeability but does not allow the earth and sand to pass through, and the pipe line portion including all of the pipe line wrapped inside the sheet and the inner sand, etc., is to prevent rising. It is necessary to exceed the specific gravity of the muddy water due to the liquefaction phenomenon. Accordingly, the material, weight, and size of the bottom plate may be determined according to this.

The sheet 2 having water permeability but not permeable to earth and sand used in the present invention is intended to prevent the floating of the pipeline, particularly the irregular rise of the pipeline, together with the bottom plate. As the sheet 2 having water permeability used in the present invention but not permeable to earth and sand, the sheet having water permeability and not permeable to earth and sand can be used. Examples of commercially available products include polyester-based short fiber nonwoven fabrics, such as Sandef (registered trademark) manufactured by Maeda Kosen Co., Ltd. Further, if it is considered that the strength is insufficient only with this sheet, the reinforcing material 5 may be used in combination. Although it does not specifically limit as a reinforcing material, The sheet | seat for embankment and ground reinforcement, especially a geogrid is mentioned as a preferable thing, As a commercially available thing, Maeda Kosen company Adem (trademark) etc. are mentioned, for example. .
In this embodiment, the sheet 2 that is water permeable but does not penetrate earth and sand is further reinforced by a reinforcing material 5, and the sheet 2 and the reinforcing material 5 are connected to the outer edge of the bottom plate. There is no particular limitation. In this embodiment, as shown in FIG. 1, a part of the sheet 2 and the reinforcing material 5 are already embedded in the bottom plate of the precast concrete. By adopting such a structure, it is possible to strongly prevent irregular rise of the pipeline due to liquefaction.
The improved soil used in the present invention is obtained by mixing and mixing an improving agent with general earth and sand, and the improving agent is generally called cement-based solidifying agent, solidifying agent, improving agent, etc. for earth and sand. There are cement-based and lime-based materials. Specifically, cement-based solidified materials include Solid Ace (registered trademark of Aso Lafarge Cement), Geoset (registered trademark of Taiheiyo Cement), etc. In the system, quick lime and slaked lime are mentioned.

  Next, the construction method will be described. First, a predetermined position to be newly installed such as a sidewalk is excavated, and temporary earth retainings 9 are installed on both right and left sides of the excavated groove. Next, the bottom surface of the groove is flattened, and a material 7 having high water permeability, that is, a material that is filled so that a relatively large number of voids are formed at the bottom of the groove, specifically, crushed stone or the like is stored. The bottom plate 1 is placed on the upper surface. Next, a pipe (electric wire) 3 is provided in the space on the bottom plate 1, and sand or improved soil 4 is disposed around the pipe 3, and the pipe 3 and the inner sand or improved soil 4 are permeable to water. Wrap it in a sheet 2 that has properties but is not transparent to earth and sand. In this embodiment, the sheet 2 is reinforced by the reinforcing material 5, and the sheet 2 and the reinforcing material 5 are connected to the outer edge of the bottom plate. Further, in this embodiment, the sheet 2 and the reinforcing material 5 are each composed of two sheets, which are overlapped at the upper part, and further, this overlapped part is locked by the spiral metal fitting 6. Thus, if it is made the structure which the upper part of the sheet | seat 2 which has water permeability but does not permeate earth and sand opens, workability | operativity will improve. Furthermore, it is preferable that the liquefied mud water can escape to the upper part if the space between the sheet 2 and the temporary earth retaining 9 and the upper part of the sheet 2 are filled with a material 7 having high water permeability, here crushed stone. And what is necessary is just to form a pavement surface on these finally.

  The connection between the conduit portion of the common wire groove of the present invention and the special portion main body 8 may be, for example, a structure as shown in FIG. 2, but is not limited thereto. This connection structure connects the end portion of the sheet 2 that is water permeable so as to surround the knockout of the special portion main body 8 side plate portion, but does not allow the earth and sand to pass through, to the special portion main body 8 side plate portion, It is fixed with the screw member 10 via the fixing bracket 11. The fixing bracket 11 has an L-shaped cross section having a first surface facing the special portion main body 8 side plate portion and a second surface facing the sheet 2. In the present embodiment, both the sheet 2 that has water permeability but does not penetrate earth and sand and the reinforcing material 5 are connected to the special part main body 8 side plate part.

  As described above, the present invention is highly industrially applicable because it can easily prevent irregular rise of the conduit portion of the common wire groove with a relatively simple structure.

1 Bottom plate 2 Sheet that has water permeability but does not penetrate earth and sand 3 Pipe line (electric wire)
4 Sand or improved soil 5 Reinforcement material 6 Metal fitting 7 Material with high water permeability

Claims (6)

  Sand or improved soil is disposed around a pipe line, the pipe line and the sand or the improved soil are gripped by a sheet that is permeable but not permeable to earth and sand, and the sheet is below the pipe line. A conduit portion of a common wire groove characterized by being connected to a bottom plate.   2. The conduit part of the electric wire joint groove according to claim 1, wherein a sheet that is water permeable but does not transmit earth and sand is further reinforced by a reinforcing material.   The conduit portion of the joint groove for electric wires according to claim 1 or 2, wherein the bottom plate is made of precast concrete.   The conduit portion of the electric wire joint groove according to any one of claims 1 to 3, wherein the bottom plate has a water drainage channel in the vertical direction.   5. The electric wire common groove tube according to claim 2, wherein a part of a sheet reinforced with a reinforcing material and having water permeability but not earth and sand is embedded in the bottom plate. Road part. A material with high water permeability is provided at the bottom of the groove, and the conduit portion of the electric wire joint groove according to any one of claims 1 to 5 is provided on the material, and a gap between the groove and the conduit portion. And the installation structure of the pipe line part of a common wire groove | channel characterized by providing material with high water permeability on this pipe line part.

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