Cable movement suppression method and deflection suppression device

Abstract

To provide a technique for suppressing the movement of a cable movement caused by a surfing phenomenon with a simple configuration at low cost in a cable movement suppression method for suppressing the movement of a cable laid inside a pipe buried underground.SOLUTION: A cable movement suppression method for suppressing the movement of a cable laid inside a pipe buried underground includes disposing a deflection suppression device between the buried pipe and the ground to suppress deflection of the pipe due to a load transmitted from the ground to the pipe. The deflection suppression device includes, for example, at least one deflection suppression member including a first plate and a second plate disposed opposite each other, with an air layer formed between the first plate and the second plate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a cable movement restraint method and a deflection restraint device. [Background technology]

[0002] One method for laying cables such as power lines, telephone lines, and communication lines underground is to run them through pipes (also called "ducts") buried underground (also called "ductwork"). It is known that when cables are laid under roads using the ductwork method, the cables laid inside the pipes may move in one direction (also called "surfing") due to vehicles traveling on the road. If the cables laid inside the pipes move, they may be damaged. Therefore, it is necessary to suppress cable movement due to surfing. For example, Patent Document 1 discloses a technique for suppressing cable movement due to surfing, in which the load acting on the cable is distributed by restraining the cable in a pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-106415 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, the cable must be attached to the pipe at various points inside the pipe, which makes the installation process time-consuming and costly. In recent years, resin pipes have been used as pipes for laying cables inside. Resin pipes are more susceptible to elastic deformation and bending than concrete pipes, which can increase the force acting on the cable due to the surf-riding phenomenon (surf-riding force). Therefore, there is a demand for the development of a simple, inexpensive technology to suppress cable movement due to the surf-riding phenomenon. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a method for suppressing movement of a cable laid inside a pipe buried underground, comprising disposing a deflection suppression device between the buried pipe and the ground to suppress deflection of the pipe due to a load transmitted from the ground to the pipe. According to this embodiment of the cable movement restraining method, the movement of the cable caused by the surf-riding phenomenon can be restrained inexpensively with a simple configuration in which the deflection restraining device is disposed underground. (2) In the cable movement suppression method of the above embodiment, the deflection suppression device may include at least one deflection suppression member including a first plate and a second plate arranged opposite each other, with an air layer formed between the first plate and the second plate. According to this form of cable movement suppression method, it is possible to suppress the deflection of the pipe caused by the load applied to the ground, and to suppress the movement of the cable caused by the surf-riding phenomenon. (3) In the cable movement restraining method of the above aspect, the deflection restraining device may include a plurality of the deflection restraining members arranged along the vertical direction. According to this form of cable movement restraining method, the wave-riding movement force generated in the cable due to the load applied to the ground can be reduced compared to when a single deflection restraining member is used. (4) In the cable movement restraining method of the above aspect, the ground may be a road on which a vehicle travels. According to this form of cable movement suppression method, it is possible to suppress the bending of the pipe that occurs when a vehicle travels on a road, and to suppress the movement of the cable that is caused by the surf-riding phenomenon. (5) In the cable movement restraining method of the above aspect, the deflection restraining device may include a plurality of the deflection restraining members arranged along the extension direction of the road. According to this embodiment of the cable movement suppression method, it is possible to suppress the movement of the cable caused by the bending of the pipe that occurs as a vehicle travels on the road. (6) In the cable movement restraining method according to the above aspect, the deflection restraining device may include an elastic member. According to the cable movement suppression method of this embodiment, it is possible to suppress the movement of the cable caused by the surf-riding phenomenon with a simpler configuration. (7) According to another aspect of the present disclosure, there is provided a deflection suppression device disposed between the ground and a pipe buried in the ground with a cable laid therein to suppress deflection of the pipe. The deflection suppression device includes at least one deflection suppression member including a first plate and a second plate disposed opposite each other, with an air layer formed between the first plate and the second plate. According to the deflection suppressing device of this embodiment, the movement of the cable caused by the surf-riding phenomenon can be suppressed inexpensively with a simple configuration in which the deflection suppressing device is disposed underground. (8) In the deflection suppressing device of the above aspect, one of the first plate and the second plate may include a plurality of ribs extending from the one plate toward the other plate. According to the deflection restraining device of this embodiment, it is possible to improve the effect of restraining the deflection of the pipe and the impact resistance of the deflection restraining member. (9) In the deflection suppressing device of the above aspect, the deflection suppressing member may further include a low-resilience member between the first plate and the second plate, the low-resilience member having a resilience lower than that of the first plate and the second plate. According to the deflection suppressing device of this configuration, movement of the cable caused by the surf-riding phenomenon can be suppressed more effectively than in a case where no synthetic resin foam is provided. (10) In the deflection suppressing device of the above aspect, the first plate may include a plurality of first ribs extending from the first plate toward the second plate, and the second plate may include a plurality of second ribs extending from the second plate toward the first plate. According to the deflection restraining device of this embodiment, it is possible to improve the effect of restraining the deflection of the pipe and the impact resistance of the deflection restraining member. (11) In the deflection suppression device of the above aspect, the first ribs may extend along a first direction intersecting with a vertical direction, and the second ribs may extend along a second direction intersecting with the vertical direction and the first direction. According to the deflection suppressing device of this embodiment, the deflection suppressing effect of the deflection suppressing member on the pipe can be improved. (12) In the deflection suppressing device of the above aspect, the deflection suppressing member may further include a low-resilience member between the first plate and the second plate, the low-resilience member having a resilience lower than that of the first plate and the second plate. According to the deflection suppressing device of this configuration, the movement of the cable caused by the surf-riding phenomenon can be suppressed more effectively than in a case where no low-resilience member is provided. (13) In the deflection suppressing device of the above aspect, the low resilience member may abut against the plurality of first ribs and the plurality of second ribs. According to the deflection suppressing device of this embodiment, the deflection suppressing effect of the deflection suppressing member can be improved. (14) The deflection suppressing device of the above aspect may include a plurality of the deflection suppressing members arranged along the vertical direction. According to this type of deflection suppression device, the wave-riding force generated in the cable due to the load applied to the ground can be reduced compared to when a single deflection suppression member is used. (15) The deflection suppressing device of the above aspect may include a plurality of the deflection suppressing members arranged side by side along a direction intersecting the vertical direction. According to the deflection suppressing device of this form, it is possible to reduce the wave-riding movement force generated in the cable over a wider range than when a single deflection suppressing member is used. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is an explanatory diagram showing an overview of a cable movement suppression method according to the first embodiment. [Figure 2] FIG. 2 is an explanatory diagram showing the configuration of a deflection suppression device in the direction in which the road extends. [Figure 3] FIG. 2 is a plan view showing the external configuration of a deflection suppressing member. [Figure 4] FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3 . [Figure 5] Cross-sectional view of the VV position in Figure 3. [Figure 6] Cross-sectional view taken along the line VI-VI in Figure 3. [Figure 7] FIG. 4 is an explanatory diagram showing the configuration of the opposing surface of the second plate. [Figure 8] FIG. 4 is an explanatory diagram showing the configuration of the opposing surface of the first plate. [Figure 9] FIG. 2 is an explanatory diagram showing the external configuration of a synthetic resin foam. [Figure 10] FIG. 10 is an explanatory diagram showing an experimental device for evaluating the effect of reducing deflection. [Figure 11] FIG. 1 is an explanatory diagram showing experimental conditions and experimental results using an experimental device. [Figure 12] FIG. 10 is a cross-sectional view showing the configuration of experimental sample number "#2." [Figure 13] FIG. 10 is a cross-sectional view showing the configuration of experimental sample number "#6." [Figure 14] FIG. 10 is a first explanatory diagram showing a modified example of a deflection suppressing member. [Figure 15] FIG. 10 is a second explanatory diagram showing a modified example of the deflection suppressing member. [Figure 16] FIG. 10 is a third explanatory diagram showing a modified example of the deflection suppressing member. [Figure 17] FIG. 4 is a fourth explanatory diagram showing a modified example of the deflection suppressing member. [Figure 18] FIG. 10 is an explanatory diagram showing a modified example of the deflection suppressing device. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: FIG. 1 is an explanatory diagram showing an overview of a cable movement suppression method according to a first embodiment. In the cable movement suppression method according to this embodiment, a conduit 90 is placed underground under a road WS on which a vehicle VH travels, and then a deflection suppression device 100 is placed between the buried conduit 90 and the road WS. The road WS is an example of the "ground surface GD." In the example of FIG. 1, the left-right direction shown in the figure is the width direction of the road WS, and the front-rear direction shown in the figure is the extension direction of the road WS (the traveling direction of the vehicle VH).

[0009] The conduit 90 is a tubular member, for example, cylindrical. The conduit 90 is also simply called a "pipe." As shown in FIG. 1 , the cable movement restraint method according to this embodiment employs a conduit system in which cables 92, such as power cables, communication cables, and telephone cables, are inserted into the conduit 90. The cables 92 are inserted into the conduit 90 and are restrained (fixed) to the conduit 90 by a restraining device (not shown). As the restraining device, a known restraining device may be used.

[0010] In this embodiment, the conduit 90 is formed of, for example, rigid polyvinyl chloride, which has relatively high load-bearing capacity, insulating properties, and flame retardancy. In the example of FIG. 1, three conduits 90 are arranged. Note that the conduit 90 is not limited to rigid polyvinyl chloride, and may be made of reinforced plastic other than polyvinyl chloride, or various materials such as metals such as iron, or concrete. Furthermore, the number of conduits 90 may be one or any number equal to or greater than two.

[0011] In this embodiment, the pipeline 90 is installed in a roadbed 40 made of, for example, excavated soil, crusty runoff, or sand. The roadbed 40 is a layer below the surface layer 20 containing an asphalt mixture or the like, and the roadbed 30 containing crusty runoff, granular crushed stone, or the like. In the example of FIG. 1 , the pipeline 90 is fixed to a pipe bolster 94 molded from a resin material such as plastic in the roadbed 40. The pipe bolster 94 is placed on pre-formed sand spreader 50. The pipe bolster 94 allows adjustment of the underground position and height of the pipeline 90.

[0012] Here, for example, when the vehicle VH travels on the road WS, the load of the vehicle VH is applied to the road WS via the wheels of the vehicle VH, etc., causing a deflection in the conduit 90. When the conduit 90 recovers from the deflection, the cable 92 may slide on the inner surface of the conduit 90. As a result, a wave-riding phenomenon occurs in which the cable 92 moves inside the conduit 90.

[0013] As shown in Fig. 1, the deflection suppression device 100 according to this embodiment is placed underground and suppresses deflection that occurs from the ground GD to the pipeline 90. As shown in Fig. 1, the deflection suppression device 100 reduces deflection that occurs in the pipeline 90 due to the running of a vehicle VH.

[0014] In this embodiment, the deflection suppression device 100 includes a deflection suppression member 80. The deflection suppression member 80 is a substantially flat plate-shaped member. The deflection suppression member 80 reduces deflection that occurs in the conduit 90 and suppresses movement of the cable 92 caused by the surf-riding phenomenon. For ease of explanation, the following description will be given taking as an example a case where the deflection suppression member 80 is installed underground with its surface direction aligned with the horizontal direction.

[0015] Fig. 2 is an explanatory diagram showing the configuration of the deflection suppression device 100 in the extension direction of the road WS. As shown in Fig. 2, the conduit 90 is arranged along the extension direction of the road WS. In the example of Fig. 2, the left-right direction shown in the figure is the extension direction of the road WS (the traveling direction of the vehicle VH), and the front-rear direction shown in the figure is the width direction of the road WS.

[0016] If the conduit 90 is arranged along the extension direction of the road WS, the location where the deflection occurs will move as the vehicle VH travels. In such a case, the cable 92 may be more likely to move within the conduit 90. If the conduit 90 is made of hard polyvinyl chloride or reinforced plastic, the conduit 90 has high flexibility, so deflection will be more pronounced compared to a concrete-lined conduit, and the movement of the cable 92 within the conduit 90 may be greater.

[0017] As shown in Fig. 2, the deflection suppression device 100 of this embodiment includes a plurality of deflection suppression members 80. The plurality of deflection suppression members 80 are arranged consecutively along the extension direction of the road WS at positions directly above the conduit 90. In other words, the plurality of deflection suppression members 80 are arranged side by side along a direction intersecting the vertical direction. By arranging the plurality of deflection suppression members 80 along the traveling direction, it is possible to suppress deflections that occur sequentially at different locations in the conduit 90 as the vehicle VH travels.

[0018] The configuration of the deflection suppressing member 80 will be described with reference to Figures 3 to 5. Figure 3 is a plan view showing the external configuration of the deflection suppressing member 80. The "thickness direction of the deflection suppressing member 80" refers to the direction in which a load is applied to the pipeline 90 when the vehicle VH travels on the road WS. The deflection suppressing member 80 is formed in the shape of a plate that extends in a direction intersecting the thickness direction.

[0019] FIG. 3 shows a first direction and a second direction. The first direction is the extension direction of a first rib 811 (described later), and the second direction is the extension direction of a second rib 822 (described later). As illustrated in FIG. 1, when the deflection suppressing member 80 is disposed horizontally underground, the first and second directions are perpendicular to the vertical direction. In this embodiment, the first direction is disposed parallel to the extension direction of the road WS shown in FIG. 2. However, the deflection suppressing member 80 may be disposed so that the first direction intersects with the extension direction of the road WS at a predetermined angle. The deflection suppressing member 80 may be disposed so that the second direction is parallel to the extension direction of the road WS.

[0020] In this embodiment, the deflection suppressing member 80 has a substantially square external shape extending in a first direction and a second direction perpendicular to the first direction in a plan view. However, the shape of the deflection suppressing member 80 is not limited to a square, and various shapes such as a rectangle or a circle can be adopted. The first direction and the second direction may be set to intersect at a predetermined angle. Furthermore, the first direction and the second direction may be parallel to each other.

[0021] 1, the deflection suppressing member 80 is buried between the conduit 90 and the road WS in order to reduce deflection of the conduit 90 caused by the load of a vehicle VH traveling on the road WS. Therefore, the width of the deflection suppressing member 80 is configured to be wider than the diameter of the conduit 90, for example. In this embodiment, the width of the deflection suppressing member 80 is set to a length that can cover three conduits 90 from above.

[0022] The internal configuration of the deflection suppressing member 80 will be described with reference to FIGS. 4 to 9. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view taken along line VV in FIG. 3. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 3. FIG. 7 is an explanatory diagram showing the configuration of the opposing surface 825 of the second plate 82. FIG. 8 is an explanatory diagram showing the configuration of the opposing surface 815 of the first plate 81. FIG. 9 is an explanatory diagram showing the external configuration of the synthetic resin foam 86. Note that FIG. 4 shows a cross-section of the first plate 81 at a position where a first rib 811 (described later) is formed, and FIG. 5 shows a cross-section of the first plate 81 at a position where the first rib 811 is not formed.

[0023] 4 and 5, the deflection suppressing member 80 includes a first plate 81 and a second plate 82. The first plate 81 and the second plate 82 are disposed opposite each other in the thickness direction. The first plate 81 and the second plate 82 extend in a planar shape in a direction intersecting the thickness direction.

[0024] The first plate 81 and the second plate 82 are formed using an elastic body such as a known rubber material. In this embodiment, a synthetic rubber such as ethylene propylene diene rubber (EPDM: Ethylene Propylene Diene Methylene Linkage) is used for the first plate 81 and the second plate 82. This makes it possible to provide a deflection suppressing member 80 that is excellent in weather resistance, heat resistance, chemical resistance, electrical insulation, low-temperature flexibility, and the like.

[0025] The hardness of the first plate 81 and the second plate 82 is evaluated, for example, by a type A durometer hardness in accordance with Japanese Industrial Standard JIS K6253. In this embodiment, the type A durometer hardness of the first plate 81 and the second plate 82 is A40 or A70.

[0026] The first plate 81 has a first rib 811, an outer edge protrusion 813, an opposing surface 815, and a first recess 817. The opposing surface 815 is a surface that faces the second plate .

[0027] 5 and 8, the outer edge protrusion 813 is formed on at least a part of the outer periphery of the opposing surface 815. The outer edge protrusion 813 protrudes from the peripheral edge of the opposing surface 815 toward the second plate 82. The outer edge protrusion 813 has a shape corresponding to the shape of the outer edge recess 823 of the second plate 82. The first recess 817 is a recess in the opposing surface 815 that is defined by the inner wall surface of the outer edge protrusion 813 and the opposing surface 815.

[0028] 5, the second plate 82 has a second rib 822, an outer edge recess 823, an opposing surface 825, and a second recess 827. The opposing surface 825 is a surface that faces the first plate 81.

[0029] 5 and 7, the outer edge recess 823 is formed on at least a part of the outer periphery of the facing surface 815, specifically, at a position corresponding to the outer edge protrusion 813 of the first plate 81. The second recess 827 is a recess in the facing surface 825 that is defined by the inner wall surface of the outer edge recess 823 and the facing surface 825.

[0030] The first plate 81 and the second plate 82 are assembled so as to face each other and extend parallel to each other. More specifically, as shown in Fig. 5, an outer edge convex portion 813 of the first plate 81 and an outer edge concave portion 823 of the second plate 82 are fitted together to form a single flat plate-like structure. Note that in this embodiment, as shown in Figs. 3 and 4, after the first plate 81 and the second plate 82 are fitted together, the assembled state is maintained by inserting pins 84 into through holes formed in the first plate 81 and the second plate 82.

[0031] In this embodiment, the thickness of the deflection suppression member 80 is configured to be approximately 15 mm. This is relatively thin compared to metal members used for reinforcement purposes, etc. Therefore, the deflection suppression device 100 can be made smaller. However, the thickness of the deflection suppression member 80 is not limited to 15 mm, and may be 10 mm, 20 mm, or any thickness of 30 mm, 50 mm, 100 mm, or more. From the viewpoint of achieving both the deflection suppression effect of the deflection suppression member 80 on the pipeline 90 and compactness, the thickness of the deflection suppression member 80 is preferably 10 mm or more and 20 mm or less. If the deflection suppression member 80 is less than 10 mm, there is a possibility that the load transmitted from the road WS cannot be sufficiently reduced.

[0032] 4 to 6, when the first plate 81 and the second plate 82 are fitted together, an air layer is formed between the first plate 81 and the second plate 82, defined by the first recess 817 and the second recess 827. The air layer is a space formed inside the deflection suppression member 80. The air layer reduces the load applied to the conduit 90 from the vehicle VH and damps deflection that occurs in the conduit 90.

[0033] As shown in FIGS. 4 to 6, in this embodiment, the deflection suppressing member 80 includes a synthetic resin foam 86 between a first plate 81 and a second plate 82. Specifically, the synthetic resin foam 86 is disposed in the air space between the first plate 81 and the second plate 82. As shown in FIG. 9, the synthetic resin foam 86 is a flat plate-shaped member having a substantially square external shape. By disposing the synthetic resin foam 86 in the internal space, deterioration of the synthetic resin foam 86 can be suppressed.

[0034] The synthetic resin foam 86 is configured to have a lower resilience than the first plate 81 and the second plate 82. The synthetic resin foam 86 is an example of a "low resilience member." A low resilience member refers to a member with a low resilience coefficient or a low modulus of resilience. The resilience coefficient of the synthetic resin foam 86 is lower than the resilience coefficients of the first plate 81 and the second plate 82, for example.

[0035] In this embodiment, the synthetic resin foam 86 is a plastic or elastomer formed as a foamed or porous body. In this embodiment, a foam containing a styrene-based elastomer is used as the synthetic resin foam 86. However, various synthetic resins may also be used for the synthetic resin foam 86, such as polyolefins such as polyethylene and polypropylene, polyurethane, polystyrene, silicone, polyvinyl chloride, and phenolic resin.

[0036] The synthetic resin foam 86 configured in this manner reduces the load applied to the pipeline 90 from the vehicle VH and damps the deflection that occurs in the pipeline 90. It is also possible to omit the synthetic resin foam 86. Whether the synthetic resin foam 86 is a low-resilience material or not can be evaluated, for example, by conducting a test in which an object is allowed to freely fall and collide with the synthetic resin foam 86, and using the rate of change between the height at which the free fall begins and the maximum height after the collision.

[0037] As shown in FIGS. 6 and 8 , the first plate 81 has at least one first rib 811 (preferably a plurality of first ribs 811 extending parallel to the first direction) that intersects with the thickness direction (preferably orthogonal to the thickness direction). The first rib 811 is formed on the opposing surface 815 of the first plate 81. The first rib 811 is a structure that extends from the first plate 81 (more specifically, the first recess 817) toward the second plate 82. In this embodiment, the first rib 811 has an external shape of a substantially rectangular parallelepiped that extends along the first direction. In this embodiment, a plurality of first ribs 811 are formed that are arranged in parallel at equal intervals in the second direction.

[0038] As shown in FIGS. 5 and 7 , the second plate 82 has at least one second rib 822 (preferably, a plurality of second ribs 822 extending parallel to the second direction) extending in a second direction intersecting the thickness direction (preferably, perpendicular to the first direction). The second rib 822 is formed on the opposing surface 825 of the second plate 82. The second rib 822 is a structure extending from the first plate 81 (more specifically, the second recess 827) toward the first plate 81. In this embodiment, the second rib 822 has an external shape of a substantially rectangular parallelepiped extending along the second direction. In this embodiment, a plurality of second ribs 822 are formed and arranged in parallel at equal intervals in the first direction. Note that the number of first ribs 811 and second ribs 822 is not limited to a plurality, and may be a single number. The second direction can be set to intersect (including "perpendicular to") the first direction or to be parallel to the first direction.

[0039] The first rib 811 and the second rib 822 distribute the load transmitted from the ground GD over the entire surface of the deflection suppressing member 80. As a result, it is possible to suppress in-plane variations in the load suppression and impact resistance of the deflection suppressing member 80. In this embodiment, the first direction and the second direction are orthogonal, and the first rib 811 and the second rib 822 are arranged so as to be orthogonal to each other, and the first ribs 811 and the second ribs 822 are arranged in a grid pattern in a plan view. Therefore, it is possible to further suppress in-plane variations in the load suppression and impact resistance of the deflection suppressing member 80.

[0040] 5 and 6, in this embodiment, the tips of the first rib 811 and the second rib 822 are configured to abut against the synthetic resin foam 86. As a result, as shown in FIG. 6, the multiple first ribs 811 divide a first air layer AL1, which is formed between the first plate 81 and the second plate 82 and is closer to the first plate 81 than the synthetic resin foam 86, into multiple regions. As shown in FIG. 5, the multiple second ribs 822 divide a second air layer AL2, which is formed closer to the second plate 82 than the synthetic resin foam 86, into multiple regions. This configuration can reduce in-plane variations in load suppression and impact resistance caused by the deflection suppressing member 80.

[0041] 10 to 13, the deflection reduction effect of the deflection suppression device 100 according to this embodiment on the pipeline 90 will be described. Fig. 10 is an explanatory diagram showing the configuration of an experimental device DE for evaluating the deflection reduction effect of the deflection suppression device 100.

[0042] The force exerted on the cable 92 when the cable 92 moves due to the wave-riding phenomenon is defined as a "wave-riding movement force F." The wave-riding movement force F (unit: N) of the cable 92 is derived, for example, by the following formula (1). F=K CC(f) V(f)+β Formula (1)

[0043] CC(f) is a coefficient related to the condition of the cable 92, and is derived, for example, by the following equation (2). CC(f)=CL(f)·LU(f)·CR(f)·W···Formula (2) CL(f): Coefficient related to the length of the cable 92 LU(f): Coefficient related to the lubricant used in the pipeline 90 (for example, the coefficient is 1.0 when no lubricant is used, and the coefficient is 0.7 when grease is used). CR(f): Coefficient related to the stiffness of the cable 92 (for example, the coefficient is 1.0 for a single-core cable). W: Coefficient related to the weight of cable 92 β: Correction value for the actual measurement value

[0044] V(f) is the vibration coefficient of the pipe 90, and is derived, for example, by the following equation (3). V(f)=(Vmax) 1.53 ...Equation (3) Vmax: Maximum deflection when a 20-ton vehicle travels at 40 km / h (unit: mm)

[0045] The wave-riding force F is proportional to the maximum deflection Vmax of the pipe 90. Here, the deflection of the pipe 90 can be calculated by integrating the acceleration occurring in the pipe 90 twice. In other words, when the "acceleration" is large, the "deflection" (the second integral of the acceleration) also becomes large, and the wave-riding force caused by the deflection becomes large. For these reasons, in this experiment, the acceleration occurring in the pipe 90 was used to evaluate the "deflection."

[0046] As shown in Figure 10, in the experimental device DE, soil and sand were placed in a concrete container HS, also known as a U-shaped gutter, to simulate the ground surface GD. The soil and sand introduced into the container HS was then compacted using a rammer or similar.

[0047] A conduit 90 similar to that shown in Fig. 1 was placed in the ground GD. A plurality of experimental samples 80S including deflection suppressing members 80 and modified deflection suppressing members 80, as will be described later, were placed above the conduit 90.

[0048] Inside the pipe 90, an acceleration (unit: m / s 2 Three acceleration sensors S1, S2, and S3 are arranged to detect the velocity of the pipe 90. For example, strain sensors are used as the acceleration sensors S1, S2, and S3. The acceleration sensors S1, S2, and S3 are installed at equal intervals at a distance LS. The acceleration sensors S1, S2, and S3 are fixed to the pipe 90 using bolts and fixing plates or the like.

[0049] A weight WT of approximately 10 kilograms was allowed to freely fall and collide with the ground GD, and the acceleration generated upon impact was detected by acceleration sensors S1, S2, and S3. The weight WT was dropped from three locations: position P1 directly above acceleration sensor S1, and positions P2 and P3 equally spaced a predetermined distance WW from position P1. The drop started from four heights: 300, 500, 700, and 1000 mm above the surface of the ground GD for each location. The number of samples (so-called N number) for each experimental condition was three or more. Although not shown in the figure, a cylindrical guide member was used to guide the weight WT along a vertical path as it was dropped onto the ground GD.

[0050] Figure 11 is an explanatory diagram showing the experimental conditions and results of the experimental device DE. For ease of explanation, Figure 11 shows only the experimental results of acceleration sensor S1 out of acceleration sensors S1, S2, and S3 shown in Figure 10. Also, only the experimental results for the experimental conditions where the weight WT height was 1000 mm and the position was P1 are shown.

[0051] As shown in Fig. 11, six types of experimental samples 80S, numbered "#1" to "#6," were used in the experiment using the experimental device DE. Sample number "#1" is the deflection suppression member 80 shown in Fig. 3 and other figures. The outer shapes of each of the samples numbered "#1" to "#6" in plan view are the same as the outer shape of the deflection suppression member 80 shown in Fig. 3, and therefore are not shown in the figures.

[0052] 12 is a cross-sectional view showing the configuration of experimental sample number "#2." Sample number "#2" is a structure (hereinafter also referred to as "deflection-reducing member 80b") in a state where the synthetic resin foam 86 has been removed from sample number "#1" (i.e., deflection-reducing member 80).

[0053] 12, in the deflection suppressing member 80b, the tip of the first rib 811 does not abut the second plate 82, and the tip of the second rib 822 does not abut the first plate 81. Therefore, an air layer AL is formed between the first plate 81 and the second plate 82. Note that in FIG. 12 and FIGS. 13 to 17, which will be described later, a cross-sectional view of each sample taken along line VI-VI in FIG. 3 is shown.

[0054] Sample number "#3" is a sample of sample number "#1" (deflection suppressing member 80) in which the first plate 81 and the second plate 82 are replaced with first and second plates whose Type A durometer hardness has been changed to A70. Sample number "#4" is a sample of sample number "#3" in which the synthetic resin foam 86 has been removed. The cross-sectional structures of sample numbers "#3" and "#4" are the same as those shown in Figures 3 and 12 above, and therefore are not shown in the figures. Sample number "#5" is a sample of sample number "#1" (deflection suppressing member 80) in which only the synthetic resin foam 86 shown in Figure 9 is used.

[0055] Figure 13 is a cross-sectional view showing the configuration of experimental sample number "6." Sample number "6" is a sample (hereinafter also referred to as "deflection suppressing member 80c") composed of a flat elastic member with a type A durometer hardness of A45 and a thickness of approximately 10 mm. The material of deflection suppressing member 80c is the same as the material of the first plate 81 and second plate 82 of sample number "#1" (deflection suppressing member 80).

[0056] The sample number "Comparative Example" shown in FIG. 11 is the result of an experiment using the experimental device DE under the condition that no samples were provided on the ground GD. In the comparative example, the detected value by the acceleration sensor S1 was 1715 (m / s 2 ) The "reduction rate" shown in FIG. 11 means the ratio of acceleration to acceleration under the conditions of the comparative example (i.e., without the deflection suppressing member 80). In the example of FIG. 11, the reduction rate is shown in units of % as the calculation result of 1.0 - (detection value of acceleration sensor S1 / 1715). The reduction rate for sample number "comparative example" is 0%.

[0057] 11, according to the experimental results, the acceleration reduction rate of sample number "#1", i.e., the acceleration reduction rate of deflection suppressing member 80 according to this embodiment, was approximately 86%. Therefore, according to deflection suppressing member 80 according to this embodiment, the deflection generated in conduit 90 due to the load applied to the ground GD can be reduced the most among the experimental sample 80S, and the wave-riding force F generated in cable 92 can be reduced the most.

[0058] According to the experimental results, the reduction rate for sample number "#2" was approximately 82%. This result indicates that the synthetic resin foam 86 is effective in reducing the wave-riding force F generated in the cable 92. Therefore, it is preferable that the deflection suppressing member 80 include the synthetic resin foam 86. However, if a high reduction rate is not required for the deflection suppressing member 80, the synthetic resin foam 86 may be omitted, as in the case of deflection suppressing member 80b. Even in this case, as shown by the experimental results, the acceleration generated in the conduit 90 can be significantly reduced compared to a comparative example not including the deflection suppressing member 80, and the wave-riding force F generated in the cable 92 can be significantly reduced. Furthermore, in this case, omitting the synthetic resin foam 86 can reduce the number of parts of the deflection suppressing device 100.

[0059] According to the experimental results, the reduction rate for sample number "#3" was approximately 77%. Furthermore, according to the experimental results, the reduction rate for sample number "#4" was approximately 67%. These results indicate that setting the hardness of the first plate 81 and the second plate 82 to A40, which is lower than A70, can further reduce the wave-riding movement force F. Note that the hardness is not limited to A40, and may be set within a predetermined range including A40, for example, A30 to A50, taking into account tolerances. Furthermore, if a high reduction rate is not required for the deflection suppression member 80, the hardness may be set to A70. In this case, the hardness may be set to A60 to A80, taking into account tolerances.

[0060] According to the experimental results, the reduction rate for sample number "#5" was approximately 69%. This result indicates that the synthetic resin foam 86 has the effect of reducing the wave-riding traveling force F. Furthermore, when compared with sample number "#1," it can be seen that the first plate 81 and the second plate 82 have the effect of reducing the wave-riding traveling force F. Therefore, it is preferable that the deflection suppressing member 80 be provided with not only the synthetic resin foam 86 but also the first plate 81 and the second plate 82. However, if a high reduction rate is not required for the deflection suppressing member 80, a deflection suppressing member 80 formed only with the synthetic resin foam 86 may be used. In this case, the wave-riding traveling force F can be reduced with a simple configuration that omits the first plate 81 and the second plate 82.

[0061] According to the experimental results, the reduction rate for sample number "#6" was approximately 44%. When compared with sample number "#5," it can be seen that the synthetic resin foam 86 is more effective at suppressing the movement of the cable 92 than the elastic member. However, if a high reduction rate is not required, a deflection suppressing member 80 comprising only an elastic member may be used. In this case, the movement of the cable caused by the surf-riding phenomenon can be suppressed with a simpler configuration.

[0062] As described above, in the cable movement suppression method according to this embodiment, a deflection suppression device 100 is disposed between the conduit 90 and the ground GD to suppress deflection of the conduit 90 due to a load transmitted from the ground GD. The acceleration generated in the conduit 90 due to the load on the ground GD can be reduced, and the wave-riding movement force F acting on the cable 92 can be suppressed. Therefore, with the simple configuration of disposing the deflection suppression device 100 underground, it is possible to inexpensively suppress movement of the cable 92 due to the wave-riding phenomenon. Any of the deflection suppression devices according to the following embodiments may be used as the deflection suppression device 100.

[0063] As shown by sample number "#1," the deflection suppression device 100 according to this embodiment is equipped with at least one deflection suppression member 80, which includes a first plate 81 and a second plate 82 arranged opposite each other, with an air layer AL formed between the first plate 81 and the second plate 82. This makes it possible to suppress deflection of the conduit 90 caused by a load applied to the ground GD, and to suppress movement of the cable 92 caused by the surf-riding phenomenon.

[0064] The deflection suppression device 100 of this embodiment is installed under the road WS on which the vehicle VH travels. Therefore, it is possible to suppress deflection of the conduit 90 that occurs when the vehicle VH travels on the road WS, and to suppress movement of the cable 92 that is caused by the surf-riding phenomenon.

[0065] The deflection suppression device 100 of this embodiment includes a plurality of deflection suppression members 80 arranged along the extension direction of the road WS. Therefore, it is possible to suppress movement of the cable 92 caused by deflection of the conduit 90 that occurs as the vehicle VH travels on the road WS.

[0066] In the deflection suppression device 100 of this embodiment, the first plate 81 is provided with a plurality of first ribs 811 extending from the first plate 81 toward the second plate 82. The second plate 82 is provided with a plurality of second ribs 822 extending from the second plate 82 toward the first plate 81. Therefore, the deflection suppression effect of the pipeline 90 and the impact resistance of the deflection suppression member 80 can be improved.

[0067] According to the deflection suppressing device 100 of this embodiment, the deflection suppressing member 80 includes, between the first plate 81 and the second plate 82, a synthetic resin foam 86 having a lower resilience than the first plate 81 and the second plate 82. With this configuration, movement of the cable 92 caused by the surf-riding phenomenon can be suppressed more effectively than in a case where the synthetic resin foam 86 is not provided.

[0068] According to the deflection suppression device 100 of this embodiment, the multiple first ribs 811 extend along a first direction that intersects with the vertical direction. The multiple second ribs 822 extend along a second direction that intersects with the vertical direction and the first direction. By arranging the first ribs 811 and the second ribs 822 in a grid shape in a plan view, the deflection suppression effect of the deflection suppression member 80 can be improved.

[0069] According to the deflection suppressing device 100 of this embodiment, the synthetic resin foam 86 abuts against the plurality of first ribs 811 and the plurality of second ribs 822. The air layer AL between the first plate 81 and the second plate 82 is divided into a plurality of regions. With this configuration, the deflection suppressing effect of the deflection suppressing member 80 can be improved.

[0070] B. Other Embodiments: (B1) FIG. 14 is a first explanatory diagram showing a modified example of the deflection suppressing member 80. FIG. 12 illustrates a deflection suppressing member 80b in which the tip of the first rib 811 does not abut the second plate 82, the tip of the second rib 822 does not abut the first plate 81, and a single air layer AL is provided between the first plate 81 and the second plate 82. Alternatively, as in a deflection suppressing member 80d shown in FIG. 14, the tip of the first rib 811 may abut against the opposing surface 825 of the second plate 82. In this case, the air layer AL is divided into multiple regions by the first rib 811. Note that instead of the first rib 811, the second rib 822 of the second plate 82 may abut against the opposing surface 815 of the first plate 81. This configuration can improve the deflection suppressing effect of the deflection suppressing member 80.

[0071] (B2) Fig. 15 is a second explanatory diagram showing a modified example of the deflection suppressing member 80. As in the deflection suppressing member 80e shown in Fig. 15, the tip of the first rib 811 and the tip of the second rib 822 may be configured to abut against each other. In this case, the air layer AL is divided into multiple regions by the first rib 811 and the second rib 822. By configuring it in this way, the deflection suppressing effect of the deflection suppressing member 80 can be improved.

[0072] (B3) FIG. 16 is a third explanatory diagram showing a modified example of the deflection suppressing member 80. As in a deflection suppressing member 80f shown in FIG. 16, the first rib 811 of the first plate 81 and the second rib 822 of the second plate 82 may be omitted. In the example of FIG. 16, an air layer AL is formed on the synthetic resin foam 86 between the first plate 81 and the second plate 82. However, the air layer AL on the synthetic resin foam 86 may be omitted by disposing the synthetic resin foam 86 so as to be sealed between the first plate 81 and the second plate 82. Even with a deflection suppressing member 80 configured in this manner, movement of the cable 92 due to the surf-riding phenomenon can be suppressed with a simple configuration and at low cost.

[0073] (B4) Figure 17 is a fourth explanatory diagram showing a modified example of the deflection suppressing member 80. As in a deflection suppressing member 80g shown in Figure 17, the synthetic resin foam 86, the first rib 811 of the first plate 81, and the second rib 822 of the second plate 82 may be omitted. In this case, a single air layer AL defined by the first recess 817 and the second recess 827 is formed between the first plate 81 and the second plate 82. Even with a deflection suppressing member 80 configured in this manner, it is possible to suppress movement of the cable 92 caused by the surf-riding phenomenon with a simple configuration and at low cost.

[0074] (B5) Figure 18 is an explanatory diagram showing a modified example of the deflection suppression device 100. As shown in Figure 18, the deflection suppression device 100 includes a plurality of deflection suppression members 80 arranged along the vertical direction. With this configuration, it is possible to further reduce the wave-riding force F generated in the cable 92 due to the load applied to the ground GD, compared to when a single deflection suppression member 80 is used. In addition, the plurality of deflection suppression members 80 are spaced apart. With this configuration, it is possible to further reduce the wave-riding force F generated in the cable 92.

[0075] (B6) In the above embodiment, an example was shown in which the deflection suppression device 100 was installed under the road WS. However, the deflection suppression device 100 may also be installed, for example, under a ground surface GD other than the road WS. In this case, it is preferable that the deflection suppression device 100 be placed under the ground surface GD where a load may be applied from the ground, such as a construction site.

[0076] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0077] Furthermore, in consideration of the spirit of the present invention and the above-described embodiment and its modified examples, the following aspects are constructed. The following aspects can be employed independently or in combination with the deflection suppression device 100 shown in the embodiment, the modified examples, other aspects, or the inventions described in the claims. [Aspect 1] The hardness of the first plate and the second plate is a type A durometer hardness of A30 or more and A50 or less in accordance with Japanese Industrial Standard JIS K6253. [Aspect 2] The thickness of the deflection suppressing member is 20 mm or less. [Aspect 3] The plurality of deflection suppressing members are arranged in a vertical direction and spaced apart from one another. [Explanation of symbols]

[0078] 20...surface layer, 30...roadbed, 40...subgrade, 80, 80b, 80c, 80d, 80e, 80f, 80g...deflection suppression member, 80S...experimental sample, 81...first plate, 82...second plate, 84...pin, 86...synthetic resin foam, 90...pipe, 92...cable, 94...pipe pillow, 100...deflection suppression device, 811...first rib, 813...outer edge convex portion, 815...opposing surface, 817...first concave portion, 822...second rib, 823...outer edge concave portion, 825...opposing surface, 827...second concave portion, AL...air layer, AL1...first air layer, AL2...second air layer, DE...experimental apparatus, GD...ground, HS...container, S1, S2, S3...acceleration sensor, VH...vehicle, LS...distance, WS...road, WT...weight

Claims

1. A cable movement suppression method for suppressing movement of a cable laid inside a pipe buried underground, comprising: a deflection suppression device is disposed between the buried pipe and the ground to suppress deflection of the pipe due to a load transmitted from the ground to the pipe; A method for restraining cable movement.

2. 2. The cable movement restraining method according to claim 1, the deflection suppressing device includes at least one deflection suppressing member including a first plate and a second plate arranged opposite to each other, with an air layer formed between the first plate and the second plate; A method for restraining cable movement.

3. 3. The cable movement restraining method according to claim 2, The deflection suppression device includes a plurality of the deflection suppression members arranged along a vertical direction. A method for restraining cable movement.

4. 3. The cable movement restraining method according to claim 2, The ground is a road on which a vehicle travels. A method for restraining cable movement.

5. 5. The cable movement restraining method according to claim 4, The deflection suppression device includes a plurality of the deflection suppression members arranged along the extension direction of the road. A method for restraining cable movement.

6. 2. The cable movement restraining method according to claim 1, The deflection suppression device includes an elastic member. A method for restraining cable movement.

7. A deflection suppression device that is disposed between the ground and a pipe that is buried underground and has a cable laid inside, and that suppresses deflection of the pipe, The device includes at least one deflection suppressing member, the deflection suppressing member including a first plate and a second plate arranged opposite to each other, with an air layer formed between the first plate and the second plate. Deflection suppression device.

8. The deflection suppression device according to claim 7, One of the first plate and the second plate includes a plurality of ribs extending from the one plate toward the other plate. Deflection suppression device.

9. The deflection suppression device according to claim 8, The deflection suppressing member further includes a low-resilience member between the first plate and the second plate, the low-resilience member having a resilience lower than that of the first plate and the second plate. Deflection suppression device.

10. The deflection suppression device according to claim 7, the first plate includes a plurality of first ribs extending from the first plate toward the second plate; the second plate includes a plurality of second ribs extending from the second plate toward the first plate; Deflection suppression device.

11. The deflection suppression device according to claim 10, The first ribs extend along a first direction intersecting a vertical direction, The second ribs extend along a second direction intersecting the vertical direction and the first direction. Deflection suppression device.

12. The deflection suppression device according to claim 11, The deflection suppressing member further includes a low-resilience member between the first plate and the second plate, the low-resilience member having a resilience lower than that of the first plate and the second plate. Deflection suppression device.

13. The deflection suppression device according to claim 12, the low-resilience member abuts against the first ribs and the second ribs; Deflection suppression device.

14. The deflection suppression device according to claim 7, The deflection suppressing member is provided in a plurality of positions along the vertical direction. Deflection suppression device.

15. The deflection suppression device according to claim 7, The deflection suppressing member is provided in a plurality of positions arranged along a direction intersecting the vertical direction. Deflection suppression device.

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