JP2016123256A - Conduit line, and method of installing cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conduit line which can absorb thermal expansion and contraction of a cable therein and can inhibit application of a local load to the cable, and a method of installing the cable.SOLUTION: A conduit line in which a cable is inserted has: a low bottom part disposed at a prescribed position in the vertical direction; a high bottom part separated from the low bottom part in the axial direction and disposed at a higher position in the vertical direction than the low bottom part; and an inclining bottom part disposed between the low bottom part and the high bottom part such that the bottom face inclines continuously in the axial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pipe line and a cable laying method.

  A power cable (hereinafter referred to as a cable) used in the underground power transmission line is laid in a pipe line provided in the ground, and is connected in a manhole provided at regular intervals in the laying direction. When a cable laid in the pipeline is energized, the cable may thermally expand and contract due to Joule heat, and may extend or contract in the axial direction from the pipeline. For this reason, in order to prevent a load from being applied to the connecting portion of the cable in the manhole due to the thermal expansion and contraction of the cable, the cable is laid in a state bent in an S shape near the connecting portion. This bent portion is called an “offset portion”.

  However, when the manhole is narrow, it may be difficult to provide an offset portion near the connection portion. For this reason, it is required to absorb or suppress the thermal expansion and contraction of the cable in the pipeline. Therefore, various pipes have been developed in order to absorb or suppress the thermal expansion and contraction of the cable in the pipe (for example, Patent Documents 1 and 2).

  In particular, Patent Document 2 discloses a pipe line provided with protrusions protruding in an annular shape inside the pipe wall at a predetermined interval along the axial direction. In the region between the annular projections, the cable hangs down due to its own weight. When the cable is energized, the amount of drooping of the cable increases, so that the thermal expansion and contraction of the cable can be absorbed in the pipeline.

JP 2002-44819 A Japanese Utility Model Publication No. 7-39240

  However, in Patent Document 2, since the cable is supported by the annular protrusion, a local load may be applied to the cable at the contact point with the annular protrusion. In this case, the mechanical or electrical characteristics of the cable may change locally.

  An object of the present invention is to provide a pipe line and a cable laying method that can absorb thermal expansion and contraction of a cable inside and suppress a local load from being applied to the cable.

According to one aspect of the invention,
A conduit through which a cable is inserted,
A low bottom portion provided at a predetermined position in the vertical direction;
A high bottom portion provided in an axial direction away from the low bottom portion, and provided at a position higher in the vertical direction than the low bottom portion;
An inclined bottom provided between the low bottom and the high bottom so that the bottom is continuously inclined in the axial direction;
A conduit is provided.

According to another aspect of the invention,
A low bottom portion provided at a predetermined position in the vertical direction, a high bottom portion provided in an axial direction away from the low bottom portion, and provided at a position higher in the vertical direction than the low bottom portion, and the low bottom portion and the high bottom portion A step of inserting the cable while supporting the cable by the high-bottom portion inside the conduit having an inclined bottom portion provided so that the bottom surface is continuously inclined in the axial direction between
A step of bending the cable by its own weight while the cable is supported by the high-bottom portion;
A cable laying method is provided.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to absorb the thermal expansion / contraction of a cable inside, the pipeline which can suppress that a local load is added to a cable, and the cable laying method are provided.

(A) is an axial sectional view showing the pipe line according to the first embodiment of the present invention, and (b) shows the pipe line when laying the cable and energizing the cable according to the first embodiment of the present invention. It is an axial sectional view shown. (A) is an axial sectional view showing a pipeline according to a second embodiment of the present invention, and (b) shows a pipeline at the time of cable laying and cable energization according to the second embodiment of the present invention. It is an axial sectional view shown.

<First Embodiment of the Present Invention>
(1) Configuration of Pipe Line A pipe line 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1A is an axial sectional view showing a pipe line according to the present embodiment. FIG. 1A shows the cable 100 when inserted into the conduit 10.

  The pipe line 10 of the present embodiment supports the cable 100 on the high-bottomed portion 220 and bends (bends) it in the vertical direction by its own weight, and supports the cable 100 from below vertically along the bent shape of the cable 100. It is configured. Details will be described below.

  In the following, the “axial direction” refers to the longitudinal direction of the conduit 10, and the “radial direction” refers to the direction perpendicular to the axial direction of the conduit 10, that is, the short direction of the conduit 10. Say. In the following, the “bottom point” of the pipe line 10 refers to a point located on the lowest vertical side in a cross section perpendicular to the axial direction at a predetermined position in the axial direction of the pipe line 10. The “bottom surface” means a surface including a bottom point at a predetermined position in the axial direction of the pipe line 10.

  In Fig.1 (a), the pipe line 10 is embed | buried under the ground, and the circumference | surroundings of the pipe line 10 are hardened with soil or concrete. Further, the conduit 10 is configured such that the cable 100 is inserted therein. The cable 100 installed in the pipe line 10 is configured as, for example, a single-core CV cable (Cross-Linked Polyethylene insulated Shearable Cable) used as an underground transmission line for high-voltage power.

  As shown in FIG. 1A, the conduit 10 of the present embodiment is configured as, for example, a cylindrical tube 200 whose inner diameter is uniform in the axial direction. The cylindrical tube 200 constituting the conduit 10 is made of, for example, FRP (Fiber Reinforced Plastics).

  For example, the pipe line 10 extends in the axial direction while being bent in an S shape (wave shape) in a direction having a vertical component. In other words, the pipe line 10 is bent in an S shape along a plane parallel to a direction having a vertical component. In the present embodiment, for example, the pipe line 10 is bent in an S shape in the vertical direction, and the cross-sectional shape in the axial direction of the pipe line 10 is a smooth sine wave shape. Accordingly, a low bottom portion 210, an inclined bottom portion 230, and a high bottom portion 220 are provided along the axial direction on the vertically lower side of the conduit 10.

  The low bottom portion 210 is provided at a predetermined position in the vertical direction. For example, among the bottom points of the pipe line 10, the bottom point is provided at the lowest position in the vertical direction. Moreover, the low bottom part 210 has a curved surface convex in the vertically downward direction, for example.

  The high bottom portion 220 is provided away from the low bottom portion 210 in the axial direction. Further, the high bottom portion 220 is provided at a position higher in the vertical direction than the low bottom portion 210. For example, among the bottom points of the conduit 10, the bottom point is provided at a position that is highest in the vertical direction. Further, the high-bottom portion 220 has, for example, a curved surface that protrudes vertically upward. The cable 100 after being inserted into the pipe line 10 is bent into an S shape by being supported by the high bottom portion 220 and being bent by its own weight.

  The inclined bottom portion 230 is provided such that the bottom surface is continuously inclined in the axial direction between the low bottom portion 210 and the high bottom portion 220. That is, no stepped portion (inflection portion) whose bottom surface changes discontinuously is formed between the low bottom portion 210 and the high bottom portion 220. When the cable 100 bends due to its own weight, the cable 100 smoothly abuts on the inclined bottom portion 230 and the like, so that a load is not locally applied to the cable 100. Further, when the cable 100 is thermally expanded and contracted, the cable 100 is bent so that the cable 100 protrudes in the vertical upward direction with a portion in contact with the inclined bottom portion 230 or the like as a fulcrum. Thereby, the extension of the cable 100 in the axial direction is suppressed. Details of these effects will be described later.

  A plurality of low bottom portions 210 and high bottom portions 220 are provided alternately in the axial direction. That is, the low bottom part 210, the inclined bottom part 230, the high bottom part 220, and the inclined bottom part 230 are repeatedly provided in this order. In the present embodiment, the plurality of low bottom portions 210 are arranged at regular intervals in the axial direction, and the plurality of high bottom portions 220 are also arranged at regular intervals in the axial direction. Moreover, the high bottom part 220 is arrange | positioned in the approximate center between the two low bottom parts 210 adjacent to an axial direction.

  Note that a low ceiling portion 260, an inclined ceiling portion 280, and a high ceiling portion 270 are provided on the vertical upper side of the conduit 10 so as to follow the low bottom portion 210, the inclined bottom portion 230, and the high bottom portion 220, respectively.

  Here, when the diameter of the cable 100 is d and the pitch (in the axial direction) between two adjacent high bottom portions 220 of the plurality of high bottom portions 220 (hereinafter, the pitch of the high bottom portions 220) is L, The pitch L of the bottom portion 220 is designed according to the bending rigidity of the cable 100. Specifically, the pitch L of the high bottom portion 220 is, for example, 20 times or more and 40 times or less the diameter d of the cable 100. If the pitch L of the high-bottom portion 220 is less than 20 times the diameter d of the cable 100, the pitch L of the high-bottom portion 220 is too short for the bending rigidity of the cable 100, and the gap between two adjacent high-bottom portions 220 is reduced. The bending of the cable 100 may be insufficient. For this reason, it may be insufficient to suppress the extension of the cable 100 in the axial direction when the cable 100 is thermally expanded and contracted. On the other hand, when the pitch L of the high-bottom portion 220 is 20 times or more the diameter d of the cable 100, the pitch L of the high-bottom portion 220 is sufficiently secured with respect to the bending rigidity of the cable 100, and the adjacent two A predetermined amount of bending in the vertical direction of the cable 100 between the two high bottom portions 220 can be ensured. Thereby, the extension of the cable 100 in the axial direction can be reliably suppressed when the cable 100 is thermally expanded and contracted. On the other hand, if the pitch L of the high-bottom portions 220 is more than 40 times the diameter d of the cable 100, the number of the high-bottom portions 220 per predetermined distance in the axial direction decreases, so that the cable 100 bends per predetermined distance in the axial direction. The number of parts (flexible parts) decreases. For this reason, it may be insufficient to suppress the extension of the cable 100 in the axial direction when the cable 100 is thermally expanded and contracted. On the other hand, when the pitch L of the high-bottom portions 220 is 40 times or less the diameter d of the cable 100, a sufficient number of the high-bottom portions 220 per predetermined distance in the axial direction is ensured, and per predetermined distance in the axial direction. A sufficient number of bent portions (flexible portions) of the cable 100 can be secured. Thereby, the extension of the cable 100 in the axial direction can be reliably suppressed when the cable 100 is thermally expanded and contracted.

  In addition, the bent shape between two high bottom portions 220 adjacent at a predetermined position is equal to the bent shape between two high bottom portions 220 adjacent at other positions. The step between the low bottom portion 210 and the high bottom portion 220 adjacent at a predetermined position is equal to the step difference between the low bottom portion 210 and the high bottom portion 220 adjacent at other positions. The step between the low bottom portion 210 and the high bottom portion 220 is equal to the step between the low ceiling portion 260 and the high ceiling portion 270.

Here, the inner diameter of the pipe line 10 (cylindrical pipe 200) is D, the step between the low bottom part 210 and the high bottom part 220 is δ, and the effective inner diameter of the pipe line 10 (between the high bottom part 220 and the low ceiling part 260). when the inside diameter) was _{D e,} effective inner diameter _{D e} of the pipe 10 is obtained by the following equation (1).
D _e = D−δ (1)

When laying a cable 100 to the conduit 10, to the cable 100 does not interfere with the lower ceiling portion 260, it effective diameter D _e of the pipe 10 is a predetermined ratio or more with respect to the diameter d of the cable 100 is necessary. On the other hand, in order to suppress the extension of the cable 100 in the axial direction when the cable 100 is thermally expanded and contracted, the amount of bending of the cable 100 in the vertical direction needs to be a predetermined amount or more. From these conditions, the step δ between the low bottom portion 210 and the high bottom portion 220 is designed as follows.

That is, the step δ between the low bottom portion 210 and the high bottom portion 220 is 20% or more and 30% or less of the diameter d of the cable 100, for example. If the step δ between the low bottom portion 210 and the high bottom portion 220 is less than 20% of the diameter d of the cable 100, the cable 100 is not sufficiently bent between the two adjacent high bottom portions 220, and the heat of the cable 100 is reduced. It may be insufficient to prevent the cable 100 from extending in the axial direction during expansion and contraction. On the other hand, when the step δ between the low bottom portion 210 and the high bottom portion 220 is 20% or more of the diameter d of the cable 100, the cable 100 is bent in the vertical direction between the two adjacent high bottom portions 220. A predetermined amount is secured, and the cable 100 can be reliably prevented from extending in the axial direction when the cable 100 is thermally expanded and contracted. On the other hand, if the level difference δ between the low bottom portion 210 and the high bottom portion 220 is more than 30% of the diameter d of the cable 100, for example, the inner diameter D of the conduit 10 is a standard value (D = about 1.5d). If, because the effective diameter _{D e} of the pipe 10 becomes smaller, the time of laying the cable 100 to the conduit 10, the cable 100 can interfere with the lower ceiling portion 260. In addition, even if the step δ between the low bottom portion 210 and the high bottom portion 220 is more than 30% of the diameter d of the cable 100, the cable extension suppressing effect of the present embodiment can be obtained technically. However, the amount of drooping deformation due to the weight of the cable 100 is limited, so that the effect of suppressing the cable extension of this embodiment is also limited to a predetermined range. Further, as the level difference δ increases, it is necessary to increase the pipeline D (in order to suppress interference of the cable 100), and there is a possibility that economic efficiency is lost. For this reason, the step δ between the low bottom portion 210 and the high bottom portion 220 is preferably 30% or less of the diameter d of the cable 100. By the step δ between the high bottom 220 and the lower bottom portion 210 is 30% or less of the diameter d of the cable 100, the effective diameter D _e of the pipe 10 becomes a predetermined ratio or more with respect to the diameter d of the cable 100 ( When D = 1.5d, D _e ≧ 1.2d from the equation (1), the cable 100 can be prevented from interfering with the low ceiling portion 260 when laying the cable 100 in the conduit 10. . Further, the inclination of the inclined bottom portion 230 can be made gentle, and a local load on the cable 100 can be suppressed.

Further, the inner diameter D of the conduit 10 (cylindrical tube 200) is 1.4 times or more the diameter d of the cable 100. When the required minimum step δ (0.2d of the above minimum value) is ensured that the inner diameter D of the conduit 10 is less than 1.4 times the diameter d of the cable 100, the conduit can be obtained from the equation (1). since the effective inner diameter _{D e} of 10 is less than 1.2d, it is difficult to insert the cable 100 into the conduit 10. On the other hand, when the necessary minimum step δ (0.2d of the above minimum value) is ensured because the inner diameter D of the conduit 10 is 1.4 times or more the diameter d of the cable 100, the tube since the effective inner diameter _{D e} of the road 10 is more than 1.2d, it is possible to stably insert the cable 100 into the conduit 10. Further, since the height of the bendable area in the vertically upward direction of the cable 100 is D + δ (1.6d or more when δ = 0.2d), the cable 100 is moved vertically upward when the cable 100 is thermally expanded and contracted. It can be bent sufficiently. The upper limit value of the inner diameter D of the pipe line 10 (cylindrical pipe 200) is not particularly limited, but from an economic viewpoint, the inner diameter D of the pipe line 10 (cylindrical pipe 200) is 2.0 times the diameter d of the cable 100. The following is preferable.

(Specific dimensions)
For example, the cable 100 is a single-core CV cable, the nominal voltage of the cable 100 is 66 kV (600 SQ) or more and 77 kV (2000 SQ) or less, and the diameter d of the cable 100 is 68 mm or more and 100 mm or less. The pitch L of the high bottom part 220 is 2.0 m or more and 4.0 m or less. The inner diameter D of the pipe line 10 (cylindrical pipe 200) is 100 mm or more and 150 mm or less. The step δ between the low bottom portion 210 and the high bottom portion 220 is 14 mm or greater and 30 mm or less.

(2) Cable laying method Next, the cable laying method according to the present embodiment will be described with reference to FIGS. 1 (a) and 1 (b). FIG.1 (b) is an axial sectional view which shows the pipe line at the time of cable laying and cable energization concerning this embodiment.

(Cable insertion process)
First, as illustrated in FIG. 1A, the cable 100 is inserted into the conduit 10 while the cable 100 is supported by each of the plurality of high-bottom portions 220.

(Cable bending process)
Next, as shown in FIG. 1B, the cable 100 is bent by its own weight in a state where the cable 100 is supported by each of the plurality of high bottom portions 220 (solid line portion in the figure). At this time, the cable 100 is bent so that the cable 100 follows the high bottom portion 220, the inclined bottom portion 230, and the low bottom portion 210. As a result, the cable 100 is bent into an S shape (snake shape). At this time, the cable 100 is supported not only by the high bottom portion 220 but also by at least one of the inclined bottom portion 230 and the low bottom portion 210. As described above, the cable 100 is laid in the pipe line 10.

(3) Effects according to the present embodiment According to the present embodiment, the following one or more effects are achieved.

(A) According to this embodiment, the pipe line 10 has the low bottom part 210, the inclination bottom part 230, and the high bottom part 220 along the axial direction, and the inclination bottom part 230 is the low bottom part 210. The bottom surface is provided so as to continuously incline in the axial direction between the bottom portion 220 and the high bottom portion 220. As a result, the pipe line 10 supports the cable 100 on the high-bottom portion 220 and bends (bends) it by its own weight in the vertical direction, and supports the cable 100 from below vertically along the bent shape of the cable 100. It is configured. As a result, the thermal expansion and contraction of the cable 100 can be absorbed in the pipe line 10, and a local load can be suppressed from being applied to the cable 100.

  Specifically, as shown in FIG. 1B, when the cable 100 is laid (before the cable 100 is energized), the cable 100 is supported by the high bottom portion 220 and bends by its own weight. Thus, it is bent into an S shape. At this time, the cable 100 is provided along the high bottom portion 220, the inclined bottom portion 230, and the low bottom portion 210. Further, the cable 100 is supported not only by the high bottom portion 220 but also by at least one of the inclined bottom portion 230 and the low bottom portion 210. As described above, the cable 100 smoothly abuts not only on the high bottom portion 220 but also on at least one of the inclined bottom portion 230 and the low bottom portion 210. Thereby, it can suppress that a local load is added to the cable 100. As a result, local changes in the mechanical or electrical characteristics of the cable 100 can be suppressed.

  Further, as shown in FIG. 1B, when the cable 100 is energized, the cable 100 is thermally expanded and contracted by Joule heat of the cable 100. At this time, at the bent portion on the lower vertical side of the cable 100, the movement of the cable 100 to the lower vertical side is restricted by at least one of the inclined bottom portion 230 and the low bottom portion 210, while the vertical portion of the cable 100 is In the upper bent portion, the vertical upper portion of the high-bottom portion 220 is open, so that the cable 100 is allowed to move vertically upward. For this reason, the cable 100 is bent so as to protrude vertically upward from the high bottom portion 220 with a portion in contact with at least one of the inclined bottom portion 230 and the low bottom portion 210 as a fulcrum (broken line in the figure). Since the extension of the cable 100 is absorbed by the bending of the cable 100 in the vertically upward direction, the extension of the cable 100 in the axial direction of the pipe line 10 is suppressed. In this way, thermal expansion and contraction of the cable 100 can be absorbed in the pipe line 10.

(B) According to this embodiment, the conduit 10 (cylindrical tube 200) is bent in an S shape (wave shape) in a direction having a vertical component, for example. Thereby, the low bottom part 210, the inclined bottom part 230, and the high bottom part 220 as described above are provided along the axial direction on the vertically lower side of the conduit 10. In this way, a structure for bending the cable 100 into an S shape can be easily manufactured simply by bending the conduit 10 (cylindrical tube 200) into an S shape.

(C) According to the present embodiment, the thermal expansion and contraction of the cable 100 can be absorbed using all the spaces (height D + δ) in the pipe line 10. Thereby, it is not necessary to increase the inner diameter of the pipe line 10 itself, and the cost for the pipe line 10 can be reduced.

  For reference, the pipeline of Patent Document 2 will be described. In the pipe line of Patent Document 2, when the cable is energized, in the region between the annular protrusions, the amount of cable sag increases, so that the thermal expansion and contraction of the cable can be absorbed in the pipe line. Has been. In this case, since the upper half space of the pipeline is not utilized, the construction cost of the pipeline may be excessive. On the other hand, according to the present embodiment, when the cable 100 is energized, the cable 100 bends in a vertically upward direction with a portion that contacts at least one of the inclined bottom portion 230 and the low bottom portion 210 as a fulcrum. By doing so, not only the lower half space of the pipe line 10 but also the upper half space of the pipe line 10 and the step (δ) of the pipe line 10 can be used to absorb thermal expansion and contraction of the cable 100. Thereby, it is not necessary to increase the inner diameter of the pipe line 10 itself, and the cost for the pipe line 10 can be reduced.

(D) According to this embodiment, there is no need to add a special structure to the cable 100 itself, and the standard cable 100 can be used to absorb the thermal expansion and contraction of the cable 100 inside the conduit 10.

  For reference, a so-called self-snake cable will be described. The self-snake cable is a cable having a spiral projection on the surface of the cable sheath, and has already been put into practical use in part. The self-snake cable is bent in an S shape by the spiral protrusion, so that the self-snake cable is prevented from extending in the axial direction. More than 20 years have passed since the self-snake cable was put to practical use, and the time to renew (replace) the self-snake cable is approaching. However, since the self-snake cable is more expensive than the standard cable, the cost for renewal may increase. On the other hand, according to this embodiment, the thermal expansion and contraction of the cable 100 can be absorbed inside the pipe line 10 using the standard cable 100. Therefore, the cost at the time of updating the cable 100 can be suppressed.

(E) According to the present embodiment, in the cable insertion process when the cable 100 is laid, the cable 100 is inserted into the duct 10 while the cable 100 is supported by each of the plurality of high bottom portions 220. In the cable insertion process, the cable 100 can be brought into contact with only the high-bottom portion 220, thereby reducing the frictional force when the cable 100 is inserted.

  For reference, a case where a cable is laid in the pipeline of Patent Document 1 will be described. The cross-sectional structure of the pipe line of Patent Document 1 is V-shaped. In the pipeline of Patent Document 1, it is said that by bringing the cable into contact with the two bottom surfaces of the V shape, the frictional force between the cable and the pipeline can be improved and the thermal expansion and contraction of the cable in the pipeline can be suppressed. Yes. However, in the pipe line of Patent Document 1, the frictional force between the cable and the pipe line increases even when the cable is laid, so that the tension when the cable is inserted (drawn) into the pipe line increases. In some cases, it may be difficult to lay the cable in the pipeline. For this reason, it may be difficult to construct a V-shaped pipeline over the entire length of the line. On the other hand, according to the present embodiment, in the cable insertion step, the cable 100 can be brought into contact with only the high bottom portion 220, thereby reducing the frictional force when the cable 100 is inserted. As a result, it is possible to reduce the tension when the cable 100 is inserted into the conduit 10, so that the conduit 10 of the present embodiment can be elongated.

(F) According to the present embodiment, even if foreign matter such as pebbles is present in the conduit 10, the foreign matter is captured by the low bottom portion 210. In the cable insertion process, since the cable 100 is inserted while the cable 100 is supported by the high bottom portion 220, the cable 100 is prevented from coming into contact with the foreign matter on the low bottom portion 210. Thereby, it can suppress that the cable sheath of the cable 100 is damaged with a foreign material.

<Second Embodiment of the Present Invention>
A second embodiment of the present invention will be described with reference to FIG. FIG. 2A is an axial cross-sectional view showing a pipe line according to this embodiment, and FIG. 2B is an axial cross-section showing a pipe line when the cable is laid and when the cable is energized according to this embodiment. FIG.

  In this embodiment, the aspect which bends a pipe line differs from 1st Embodiment. Hereinafter, only elements different from those of the first embodiment will be described, and elements substantially the same as those described in the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

(1) Configuration of Pipe Line The cylindrical pipe 202 constituting the pipe line 12 of the present embodiment is constituted by, for example, a flexible member. Examples of the flexible member include polyethylene, high density polyethylene (HDPE), and polyvinyl chloride (PVC).

  As shown in FIG. 2A, a groove 90 is provided in the ground where the pipe 12 is embedded. A support portion 302 is provided at a predetermined position on the bottom surface of the groove portion 90. And the flexible cylindrical pipe | tube 202 which comprises the pipe line 12 is mounted so that the support part 302 and the groove part 90 may be followed. The high-bottom portion 222 of the pipe line 12 is provided at a position overlapping the support portion 302 when viewed from vertically above, and is supported by the support portion 302 from below vertically. Thereby, the pipe line 12 bends in an S shape in the vertical direction, and a low bottom part 212, an inclined bottom part 232, and a high bottom part 222 are provided along the axial direction on the vertical lower side of the pipe line 12. In addition, the circumference | surroundings of the pipe line 12 and the circumference | surroundings of the groove part 90 and the support part 302 are hardened with soil or concrete.

  Further, for example, the vertical upper surface of the support portion 302 is curved in an arc shape so as to be convex upward. The bottom surface of the inclined bottom portion 232 provided between the low bottom portion 212 and the high bottom portion 222 is smoothly inclined in the axial direction by bending the conduit 12 along the curved shape of the vertical upper surface of the support portion 302. doing.

  The support portion 302 is made of, for example, concrete or FRP. As described above, since the support portion 302 is made of a material having a predetermined rigidity, the support portion 302 is deformed by the weight of the cable 100 even when the cable 100 is inserted into the conduit 12. Can be suppressed.

  A plurality of support portions 302 are provided along the axial direction of the pipe line 12. The pitch between two adjacent support portions 302 among the plurality of support portions 302 is a predetermined interval L, and the pitch between two adjacent high bottom portions 222 among the plurality of high bottom portions 222 (high The pitch of the bottom portion 222) is equal to the pitch between two adjacent support portions 302 among the plurality of support portions 302, and has a predetermined interval L. For example, the pitch L of the high bottom portion 222 is, for example, not less than 20 times and not more than 40 times the diameter d of the cable 100 as in the first embodiment.

  Further, the step δ between the low bottom portion 212 and the high bottom portion 222 is equal to the height of the support portion 302. The step δ between the low bottom portion 212 and the high bottom portion 222 is, for example, not less than 20% and not more than 30% of the diameter d of the cable 100 as in the first embodiment.

  Further, the inner diameter D of the conduit 12 (cylindrical tube 202) is 1.4 times or more the diameter d of the cable 100, as in the first embodiment.

(2) Effects according to the present embodiment According to the present embodiment, the following one or more effects are achieved.

(A) According to the present embodiment, the pipe line 12 is constituted by a flexible member, and the high bottom part 222 of the pipe line 12 is supported by the support part 302 from the vertically lower side. Thereby, the pipe line 12 bends in an S shape in the vertical direction, and a low bottom part 212, an inclined bottom part 232, and a high bottom part 222 are provided along the axial direction on the vertical lower side of the pipe line 12. As a result, as in the first embodiment, the thermal expansion and contraction of the cable 100 can be absorbed in the conduit 12, and the local load on the cable 100 can be suppressed.

  Specifically, as illustrated in FIG. 2B, when the cable 100 is laid (before the cable 100 is energized), the cable 100 includes the high bottom portion 222, the inclined bottom portion 232, and the low bottom portion 212. And at least one of the inclined bottom portion 232 and the low bottom portion 212 abuts smoothly. Thereby, it can suppress that a local load is added to the cable 100.

  Further, as shown in FIG. 2B, when the cable 100 is energized, the cable 100 has a high bottom portion with a portion that contacts at least one of the inclined bottom portion 232 and the low bottom portion 212 as a fulcrum. It is bent so as to protrude vertically upward from 222 (broken line in the figure). Thereby, it is suppressed that the cable 100 extends in the axial direction of the pipe line 10. In this way, thermal expansion and contraction of the cable 100 can be absorbed in the pipe line 12.

(B) According to the present embodiment, the conduit 12 bent in an S-shape is easily manufactured by simply placing the flexible cylindrical tube 202 so as to follow the support portion 302 and the groove portion 90. be able to. There is no need to use a special cylindrical tube, and the flexible cylindrical tube 202 existing in the current market can be used. Thereby, the pipe line 12 can be manufactured at low cost.

<Other Embodiments of the Present Invention>
As mentioned above, although embodiment and modification of this invention were described concretely, this invention is not limited to the above-mentioned embodiment and modification, and can be variously changed in the range which does not deviate from the summary.

  In the second embodiment described above, the case where the support portion 302 is provided as a separate body from the cylindrical tube 202 has been described. However, the support portion may be considered as a part of the conduit, and the support portion is attached to the cylindrical tube. It may be done.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

(Appendix 1)
According to one aspect of the invention,
A conduit through which a cable is inserted,
A low bottom portion provided at a predetermined position in the vertical direction;
A high bottom portion provided in an axial direction away from the low bottom portion, and provided at a position higher in the vertical direction than the low bottom portion;
An inclined bottom provided between the low bottom and the high bottom so that the bottom is continuously inclined in the axial direction;
A conduit is provided.

(Appendix 2)
Preferably, the conduit according to appendix 1,
The cable is supported on the high-bottom portion and bent in the vertical direction by its own weight, and the cable is supported from below vertically along the bent shape of the cable.

(Appendix 3)
Preferably, the conduit according to appendix 1 or 2,
The low bottom portion, the inclined bottom portion, and the high bottom portion are provided along the axial direction by bending in an S shape in a direction having a vertical component.

(Appendix 4)
Preferably, the pipe line according to any one of appendices 1 to 3,
Consists of flexible members,
The high bottom portion is supported by a support portion from the vertically lower side.

(Appendix 5)
Preferably, the pipe line according to any one of appendices 1 to 4,
A plurality of the low bottom portions and the high bottom portions are alternately provided in the axial direction.

(Appendix 6)
Preferably, the conduit according to appendix 5,
The pitch between two adjacent high bottom portions of the plurality of high bottom portions is not less than 20 times and not more than 40 times the diameter of the cable.

(Appendix 7)
Preferably, the pipe line according to any one of appendices 1 to 6,
A step between the low bottom portion and the high bottom portion is 20% or more and 30% or less of the diameter of the cable.

(Appendix 8)
Preferably, the pipe line according to any one of appendices 1 to 7,
A low ceiling portion, an inclined ceiling portion, and a high ceiling portion provided so as to follow the low bottom portion, the inclined bottom portion, and the high bottom portion, respectively.

(Appendix 9)
Preferably, the pipe line according to any one of appendices 1 to 8,
The inner diameter is uniform in the axial direction.

(Appendix 10)
According to another aspect of the invention,
A low bottom portion provided at a predetermined position in the vertical direction, a high bottom portion provided in an axial direction away from the low bottom portion, and provided at a position higher in the vertical direction than the low bottom portion, and the low bottom portion and the high bottom portion A step of inserting the cable while supporting the cable by the high-bottom portion inside the conduit having an inclined bottom portion provided so that the bottom surface is continuously inclined in the axial direction between
A step of bending the cable by its own weight while the cable is supported by the high-bottom portion;
A cable laying method is provided.

(Appendix 11)
Preferably, the cable laying method according to appendix 10,
In the process of bending the cable by its own weight,
The cable is bent so that the cable follows the high bottom portion, the inclined bottom portion, and the low bottom portion.

(Appendix 12)
Preferably, the cable laying method according to appendix 10 or 11,
In the process of bending the cable by its own weight,
The cable is supported by at least one of the inclined bottom portion and the low bottom portion.

10, 12 Pipe line 90 Groove part 100 Cable 200, 202 Cylindrical pipe 210, 212 Low bottom part 220, 222 High bottom part 230, 232 Inclined bottom part 260 Low ceiling part 270 High ceiling part 280 Inclined ceiling part 302 Support part

Claims (8)

A conduit through which a cable is inserted,
A low bottom portion provided at a predetermined position in the vertical direction;
A high bottom portion provided in an axial direction away from the low bottom portion, and provided at a position higher in the vertical direction than the low bottom portion;
An inclined bottom provided between the low bottom and the high bottom so that the bottom is continuously inclined in the axial direction;
Having a pipeline.   The conduit according to claim 1, wherein the cable is configured to be supported by the high bottom portion and bent in a vertical direction by its own weight, and to support the cable from a vertically lower side along a bent shape of the cable.   The pipe line according to claim 1 or 2, wherein the low bottom portion, the inclined bottom portion, and the high bottom portion are provided along the axial direction by bending in an S shape in a direction having a vertical component. Consists of flexible members,
The pipe line according to any one of claims 1 to 3, wherein the high bottom portion is supported by a support portion from a vertically lower side.   The pipe line according to any one of claims 1 to 4, wherein a plurality of the low bottom portions and the high bottom portions are alternately provided in the axial direction.   The pipe line according to claim 5, wherein a pitch between two adjacent high bottom portions of the plurality of high bottom portions is not less than 20 times and not more than 40 times the diameter of the cable.   The pipe line according to any one of claims 1 to 6, wherein a step between the low bottom portion and the high bottom portion is 20% or more and 30% or less of a diameter of the cable. A low bottom portion provided at a predetermined position in the vertical direction, a high bottom portion provided in an axial direction away from the low bottom portion, and provided at a position higher in the vertical direction than the low bottom portion, and the low bottom portion and the high bottom portion A step of inserting the cable while supporting the cable by the high-bottom portion inside the conduit having an inclined bottom portion provided so that the bottom surface is continuously inclined in the axial direction between
A step of bending the cable by its own weight while the cable is supported by the high-bottom portion;
A cable laying method comprising:

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