JP7553910B2 - Underground buried object protection equipment - Google Patents

Description

The present invention relates to underground buried object protection equipment that protects buried objects buried underground.

In recent years, for example, communication cables, gas and water pipes are buried underground as buried objects. These buried objects can be damaged, for example, during road construction work, by being cut by the blade of a concrete cutter or the claws of a backhoe, or by holes being made in them by striking them with the chisel of a jackhammer or concrete breaker.

Therefore, various types of equipment for protecting objects buried underground have been proposed to prevent damage to objects buried underground (see, for example, Patent Documents 1 to 3).

For example, the protective gear according to Example 1 of Patent Document 1 is characterized in that it comprises a hollow, flat box whose exterior is made of a rigid body, a high-strength fiber sheet that is laid across the inner bottom surface of the box, a spacer member that positions the high-strength fiber sheet above the inner bottom surface of the box, and an elastic body placed on the high-strength fiber sheet, the elastic body being made of an air bag, and the elastic body is stored between the inner ceiling of the box and the box so as to temporarily press and hold the members stored in the box.

The protective gear according to Example 2 of Patent Document 1 is characterized in that it comprises a hollow flat box whose exterior is made of a rigid body, a high-strength fiber sheet that is laid out on the inner bottom surface of the box, a sealing film that airtightly encases the high-strength fiber sheet, a spacer member that raises the internal pressure in the sealing film to position the high-strength fiber sheet wrapped in the sealing film above the inner bottom surface of the box, and an elastic body that contains the swelling caused by the internal pressure created by the sealing film, and that the elastic body is placed between the inner ceiling of the box and the box so as to temporarily press and hold the components stored in the box.

Furthermore, the protective gear according to Example 3 of Patent Document 1 is characterized in that in the protective gear described in Example 1 or Example 2, the spacer member is made of an elastic material, and a steel plate shaped to be laid on the inner bottom surface of the box is interposed between the spacer member and the high-strength fiber sheet.

Patent No. 5322010 Patent No. 4351077 JP 2007-37240 A

The present invention aims to provide underground buried object protection equipment that provides higher protection than conventional equipment.

An underground buried object protective equipment according to one embodiment of the present invention comprises a box body having an upper cover and a lower box, a highly work-hardened steel plate laid on the inner bottom surface of the lower box, and a high-strength fiber sheet laid on the upper surface of the highly work-hardened steel plate and shaped like a mesh formed by weaving fibers and having gaps that are surrounded by fibers .

In the above underground buried object protection equipment, the upper cover and lower box may be made of hot-dip Zn-Al-Mg alloy-plated steel sheet.

In the above underground buried object protection equipment, the highly work-hardened steel plate may be a high carbon, high manganese steel plate.

In the above-mentioned underground buried object protection equipment, the high-strength fiber sheet may be made of aramid fiber, synthetic fiber mixed with aramid fiber, or fiber made of polypropylene, polystyrene, or polycarbonate.

In the above-mentioned underground buried object protection equipment, the upper cover has a top plate and a peripheral wall formed on the periphery of the top plate and extending downwardly from the top plate, and the lower box has a bottom plate and a peripheral wall formed on the periphery of the bottom plate and extending upwardly from the bottom plate, and when the upper cover is assembled to the lower box, the peripheral wall of the lower box is positioned outside the peripheral wall of the upper cover, and a protrusion may be formed at the upper end of the peripheral wall of the lower box that protrudes above the top plate .

In the above underground buried object protection equipment, the highly work-hardened steel plate may be formed into an overall curved shape so as to form a single convex shape on the upper side.

The above underground buried object protection equipment may comprise only a box body, a highly work-hardened steel plate, and a high-strength fiber sheet.

The above underground buried object protection equipment may further include a spacer member disposed between the highly work-hardened steel plate and the high-strength fiber sheet.

In the above-mentioned underground buried object protection equipment, the spacer is a frame body that conforms to the outer shape of the highly work-hardened steel plate, and the high-strength fiber sheet may be spaced apart from the upper surface of the highly work-hardened steel plate inside the spacer frame.

The above underground buried object protection equipment may further include a waterproof cover that covers the upper surface of the highly work-hardened steel plate.

The present invention provides underground buried object protection equipment that provides higher protection than conventional equipment.

1 is a cross-sectional view showing an example of an underground buried object protector according to one embodiment of the present invention buried beneath the ground surface together with a plurality of buried objects. FIG. FIG. 2 is an exploded perspective view of the underground buried object protection equipment shown in FIG. 1 . FIG. 2 is a cross-sectional view of the underground buried object protection equipment shown in FIG. 1. FIG. 4 is a plan view showing a portion of the high-strength fiber sheet shown in FIG. 3 . 2 is a vertical cross-sectional view showing an example of a state in which the blade of a concrete cutter hits the underground buried object protection equipment shown in FIG. 1 . FIG. 2 is a vertical cross-sectional view showing an example of a state in which a chisel of a concrete breaker hits the underground buried object protection equipment shown in FIG. 1 . FIG. 2 is a vertical cross-sectional view showing a first modified example of the underground buried object protection equipment shown in FIG. 1. 1. FIG. 4 is an exploded perspective view showing a second modified example of the underground buried object protection equipment shown in FIG. FIG. 9 is a vertical cross-sectional view of the underground buried object protection equipment shown in FIG. 8. 9 is a vertical cross-sectional view showing an example of a state in which the blade of a concrete cutter hits the underground buried object protector shown in FIG. 8 . 1. FIG. 4 is a vertical cross-sectional view showing a third modified example of the underground buried object protection equipment shown in FIG.

One embodiment of the present invention is described below.

First, a description will be given of conventional underground buried object protective equipment and the problems associated with it that are envisaged in one embodiment of the present invention. Conventional underground buried object protective equipment has been proposed that includes an elastic body made of an air bag in addition to a box body, a high-strength fiber sheet, and a spacer member. With this protective equipment, the number of parts increases compared to when the protective equipment is made of, for example, a box body, a high-strength fiber sheet, and a spacer member, resulting in increased costs.

Furthermore, a conventional type of underground buried object protective equipment has been proposed that includes an elastic body made of a sealing film in addition to a box body, a high-strength fiber sheet, and a spacer member. This type of protective equipment requires more parts than, for example, a protective equipment made of a box body, a high-strength fiber sheet, and a spacer member, resulting in increased costs.

Furthermore, a conventional underground buried object protection device has been proposed that includes a box body, a high-strength fiber sheet, a spacer member, and a steel plate. This device requires more parts than a device that is composed of a box body, a high-strength fiber sheet, and a steel plate, resulting in increased costs.

Conventional underground buried object protection equipment has been proposed with steel plate thicknesses of 9 mm to 16 mm. This equipment is heavy because the steel plate is thick.

The embodiment of the present invention described below proposes, as an example, a protective gear for underground buried objects that can provide high protection while suppressing increases in cost and weight compared to the conventional protective gear for underground buried objects described above.

Figure 1 is a cross-sectional view showing an example of an underground buried object protector 10 according to an embodiment of the present invention buried under the ground surface 50 together with multiple buried objects 54. The arrow UP indicates the vertically upward direction. A concrete trough 52 formed with a U-shaped cross section is buried under the ground surface 50, and the underground buried object protector 10 is placed on top of the concrete trough 52. The underground buried object protector 10 covers an opening formed in the top of the concrete trough 52.

A plurality of buried objects 54 are installed inside the concrete trough 52. The plurality of buried objects 54 are, for example, communication cables, gas and water pipes, etc. The plurality of buried objects 54 are not particularly limited and may be any type. The plurality of buried objects 54 are placed on the inner bottom surface of the concrete trough 52. The interior of this concrete trough 52 is filled with river sand 56, for example.

Figure 2 is an exploded perspective view of the underground buried object protection equipment 10 shown in Figure 1, and Figure 3 is a cross-sectional view of the underground buried object protection equipment 10 shown in Figure 1. The underground buried object protection equipment 10 includes a box body 12, a highly work-hardened steel plate 14, and a high-strength fiber sheet 16.

The box body 12 is formed of a flat hollow body. As an example, the box body 12 is formed in a rectangular shape when viewed from above. Note that the box body 12 may be formed in a shape other than a rectangular shape when viewed from above.

This box body 12 has an upper lid 18 and a lower box 20. The upper lid 18 has a top plate 22 and a peripheral wall 24, and the lower box 20 has a bottom plate 26 and a peripheral wall 28. When the upper lid 18 is assembled to the lower box 20, the peripheral wall 28 of the lower box 20 is located inside the peripheral wall 24 of the upper lid 18. The upper lid 18 is assembled to the lower box 20 with the highly work-hardened steel plate 14 and the high-strength fiber sheet 16 (described later) housed in the lower box 20, and a waterproof seal is applied to the gap between the upper lid 18 and the lower box 20. The waterproof seal is, for example, welding. This seals the inside of the box body 12 and ensures waterproofing, thereby suppressing corrosion of the highly work-hardened steel plate 14 and deterioration of the high-strength fiber sheet 16.

The top cover 18 and the bottom box 20 are, for example, made of hot-dip Zn-Al-Mg alloy-plated steel sheet (ternary plated steel sheet), which has excellent corrosion resistance. Hot-dip Zn-Al-Mg alloy-plated steel sheet refers to a steel sheet that includes a steel sheet and a plating layer, with the plating layer containing Zn, Al, and Mg.

The highly work-hardening steel plate 14 is laid on the inner bottom surface of the lower box 20, i.e., on the top surface of the bottom plate 26. As an example, the highly work-hardening steel plate 14 is formed in a flat plate shape. This highly work-hardening steel plate 14 is formed in the same planar shape as the inner bottom surface, i.e., in a rectangular shape when viewed from above. In addition, this highly work-hardening steel plate 14 is large enough to cover the entire inner bottom surface. This highly work-hardening steel plate 14 has high work hardening properties. High work hardening properties, for example, are excellent in the property of becoming harder when processing such as bending is performed than before processing is performed.

This high work-hardening steel plate 14 is, for example, a high carbon, high manganese steel plate. The high carbon, high manganese steel plate used for the high work-hardening steel plate 14 is, for example, a steel plate containing 0.5% or more C (carbon) and 10% or more Mn (manganese). The plate thickness of the high work-hardening steel plate 14 is, for example, 3.5 mm or more and 9 mm or less.

When the thickness of the high work-hardening steel plate 14 is 3.5 mm or more, it is expected that the high work-hardening steel plate 14 can be prevented from being perforated even when it is struck by the chisel of a concrete breaker, as described below. On the other hand, when the thickness of the high work-hardening steel plate 14 is 9 mm or less, it is possible to achieve a reduction in weight compared to the above-mentioned conventional underground buried object protection equipment.

The high-strength fiber sheet 16 is laid on the upper surface of the highly processed and hardened steel plate 14. The high-strength fiber sheet 16 is formed, for example, from aramid fiber or synthetic fiber mixed with aramid fiber. The high-strength fiber sheet 16 may also be formed from high-strength fibers made of polypropylene, polystyrene, or polycarbonate. High strength means having high tensile strength. The high-strength fiber sheet 16 also has high heat resistance.

Figure 4 is a plan view showing a part of the high-strength fiber sheet 16 shown in Figure 3. The high-strength fiber sheet 16 is formed in a mesh shape by a plurality of fibers 16A. The mesh shape is, for example, a shape formed by weaving fibers and having gaps (mesh) surrounded by the fibers. The weaving method of the mesh shape of the high-strength fiber sheet 16 is not particularly limited, but in this embodiment, a twill weave is used as an example of the weaving method. The weaving method of the high-strength fiber sheet 16 may be any weaving method such as plain weave or twill weave other than twill weave. If the high-strength fiber sheet 16 is in a mesh shape, when the high-strength fiber sheet 16 comes into contact with the blade of a concrete cutter as described below, the fibers of the high-strength fiber sheet 16 are easily unraveled and easily entangled with the blade of the concrete cutter, and are difficult to cut.

The mesh size of the high-strength fiber sheet 16 is preferably 1 mm x 1 mm or more. However, if the mesh is too large, the amount of fiber caught between the blade of the concrete cutter and the high work-hardening steel plate 14 will be reduced, and the combined force of the force with which the blade rotates to cut the high work-hardening steel plate 14 and the tensile force trying to tear off the fibers will exceed the combined force of the cutting resistance of the high work-hardening steel plate 14, the tensile (shear) force of the fibers, and the frictional force between the fibers, blade, and high work-hardening steel plate due to the fibers being caught, which may result in the fibers being cut. Therefore, the mesh size is preferably 10 mm x 10 mm or less.

According to experiments conducted by the inventors, for a concrete cutter with a diamond tip portion of the blade that is 3.1 mm thick, a blade portion that is 2.5 mm thick, and a blade diameter of 370 mm, if the mesh size of the high-strength fiber sheet 16 is 3 mm x 4 mm, the fibers are difficult to cut and tend to become entangled in the blade of the concrete cutter.

In addition, in order to prevent costs from increasing, the above-mentioned underground buried object protection equipment 10 is configured to include only the above-mentioned box body 12, highly work-hardened steel plate 14, and high-strength fiber sheet 16, as an example.

Figure 5 is a vertical cross-sectional view showing an example of a state in which the blade 60 of a concrete cutter hits the underground buried object protection equipment 10 shown in Figure 1. When the blade 60 of the concrete cutter hits the underground buried object protection equipment 10 from the side, the blade 60 cuts into the box body 12. However, before the entire underground buried object protection equipment 10 is cut by the blade 60, the high-strength fiber sheet 16 becomes entangled in the groove 62 of the blade 60. At this time, since the high-strength fiber sheet 16 is in a mesh shape, when the high-strength fiber sheet 16 touches the concrete cutter blade 60, the fibers of the high-strength fiber sheet 16 are easily loosened and easily entangled in the concrete cutter blade 60, and are difficult to cut. Therefore, the blade 60 accurately bites into the cutting groove formed in the box body 12 by the blade 60 together with the high-strength fiber sheet 16, so that the resistance to the rotation of the blade increases and the rotation of the blade stops. This stops the blade 60 from cutting the underground buried object protection equipment 10, preventing damage to the buried object.

Figure 6 is a vertical cross-sectional view showing an example of a state in which the chisel 70 of a concrete breaker hits the underground buried object protector 10 shown in Figure 1. When the chisel 70 of the concrete breaker hits the underground buried object protector 10 from above, the chisel 70 penetrates the top plate 22 of the upper cover 18. However, before the chisel 70 penetrates the entire underground buried object protector 10, the highly work-hardened steel plate 14 receives the chisel 70. At this time, since the highly work-hardened steel plate 14 has work hardening properties, when the chisel 70 hits the highly work-hardened steel plate 14, the highly work-hardened steel plate 14 is work-hardened. Therefore, the resistance force against the chisel 70 increases, and the descent of the chisel 70 stops. This prevents the chisel 70 from penetrating the underground buried object protector 10, preventing damage to the buried object.

Next, we will explain the operation and effects of one embodiment of the present invention.

As described above in detail, in the underground buried object protection equipment 10 according to one embodiment of the present invention, the high-strength fiber sheet 16 is mesh-like, so that when the high-strength fiber sheet 16 comes into contact with the concrete cutter blade 60, the fibers of the high-strength fiber sheet 16 tend to easily loosen and become entangled in the concrete cutter blade 60, and are difficult to cut. Therefore, the blade 60 precisely bites into the cutting groove formed in the box body 12 together with the high-strength fiber sheet 16, increasing the resistance to the rotation of the blade 60 and stopping the rotation of the blade 60. This stops the blade 60 from cutting the underground buried object protection equipment 10, preventing damage to the buried object 54.

In addition, in the underground buried object protection equipment 10 according to one embodiment of the present invention, the highly work-hardened steel plate 14 has work hardening properties, so when the chisel 70 hits the highly work-hardened steel plate 14, the highly work-hardened steel plate 14 undergoes work hardening. Therefore, the resistance to the chisel 70 increases, and the descent of the chisel 70 stops. This prevents the chisel 70 from penetrating the underground buried object protection equipment 10, preventing damage to the buried object 54.

In this way, according to the underground buried object protective equipment 10 of one embodiment of the present invention, the high strength fiber sheet 16 is in a mesh shape, and the highly work-hardened steel plate 14 has work-hardening properties, so that it can exhibit higher protective properties than the above-mentioned conventional underground buried object protective equipment that does not have these characteristics.

Moreover, the underground buried object protection equipment 10 according to one embodiment of the present invention is configured to include only a box body 12, a highly work-hardened steel plate 14, and a high-strength fiber sheet 16. Therefore, compared to the above-mentioned conventional underground buried object protection equipment that includes an air bag, a sealing film, or a spacer member, the number of parts can be reduced, leading to cost reduction.

In addition, according to the underground buried object protective gear 10 of one embodiment of the present invention, the high work-hardening steel plate 14 has work hardening properties, so high impact resistance can be ensured, and the plate thickness of the high work-hardening steel plate 14 can be made thin. This makes it possible to suppress the increase in weight compared to the above-mentioned conventional underground buried object protective gear, which requires the steel plate to be thick.

(First Modification)
Next, a modified example of the embodiment of the present invention will be described.

Figure 7 is a vertical cross-sectional view showing a first modified example of the underground buried object protection equipment 10 shown in Figure 1. In the modified example shown in Figure 7, the configuration of the underground buried object protection equipment 10 has been changed as follows compared to the above embodiment.

In other words, in the underground buried object protection equipment 10 shown in FIG. 7, when the upper cover 18 is assembled to the lower box 20, the peripheral wall 28 of the lower box 20 is located outside the peripheral wall 24 of the upper cover 18. The peripheral wall 28 of the lower box 20 is formed with a protrusion 30. The protrusions 30 may be formed in a plurality of locations at intervals on the peripheral wall 28 of the lower box 20, or may be formed in a ring shape along the peripheral wall 28 of the lower box 20. The protrusions 30 protrude upward beyond the upper cover 18. The protrusions 30 are also formed with a through hole 32 that penetrates horizontally. The highly work-hardened steel plate 14 is also formed in a curved shape that is convex upward.

In the underground buried object protector 10 shown in FIG. 7, protrusions 30 are formed on the peripheral wall 28 of the lower box 20. Even if the vehicle's braking force or the like acts on the surface layer covering the underground buried object protector 10 when the underground buried object protector 10 is buried shallow underground, the protrusions 30 can prevent the surface layer from slipping against the underground buried object protector 10. This can increase the adhesion between the surface layer and the underground buried object protector 10.

In addition, since the protrusions 30 are formed with through holes 32, it is possible to connect multiple underground buried object protectors 10 by, for example, fixing the protrusions 30 of multiple underground buried object protectors 10 arranged horizontally together with a locking member or a cable tie. This makes it possible to prevent the buried positions of multiple underground buried object protectors 10 from shifting over time.

In addition, in the underground buried object protection equipment 10 shown in FIG. 7, the highly work-hardened steel plate 14 is formed in a curved shape that is convex upward. Therefore, when the blade 60 of the concrete cutter hits the underground buried object protection equipment 10 from the side, the inclination of the highly work-hardened steel plate 14 causes the high-strength fiber sheet 16 to move toward the blade, making it easier for the fibers of the high-strength fiber sheet 16 to become entangled with the blade of the concrete cutter. This improves the cut resistance of the high-strength fiber sheet 16.

In addition, when the chisel 70 of the concrete breaker hits the high work-hardening steel plate 14, the inclination of the high work-hardening steel plate 14 disperses the impact points of the chisel 70, preventing the impact points from concentrating at one point. This improves the impact resistance of the high work-hardening steel plate 14.

(Second Modification)
Next, a second modified example of the embodiment of the present invention will be described.

Figure 8 is an exploded perspective view showing a second modified example of the underground buried object protection equipment 10 shown in Figure 1. In the modified example shown in Figure 8, the configuration of the underground buried object protection equipment 10 is changed as follows compared to the above embodiment.

That is, in the underground buried object protection equipment 10 shown in FIG. 8, a spacer 80 is further provided between the highly work-hardened steel plate 14 and the high-strength fiber sheet 16, and the high-strength fiber sheet 16 is separated from the upper surface of the highly work-hardened steel plate 14.

The spacer 80 is a frame that conforms to the outer shape of the highly work-hardened steel plate 14, and in this embodiment, as an example, is a frame that is rectangular in plan view. The shape of the spacer 80 may be of any size as long as it can be housed inside the lower box 20 and the upper cover 18, but preferably, the frame portion of the spacer 80 is a round bar with a diameter of 5 to 7 mm (6 mm in this embodiment). The material of the spacer 80 is, for example, polyethylene foam.

Figure 9 is a vertical cross-sectional view of the underground buried object protection equipment 10 according to this modified example. As shown in Figure 9, the high-strength fiber sheet 16 is wrapped around at least two opposing sides of the spacer 80 from above and fixed in a tensioned state. Therefore, the high-strength fiber sheet 16 maintains a distance from the high work-hardened steel plate 14 inside the frame of the spacer 80. Note that the high-strength fiber sheet 16 may be wrapped around the four sides of the spacer 80 and tensioned in two perpendicular directions.

Figure 10 is a vertical cross-sectional view showing an example of a state in which the blade 60 of a concrete cutter hits the underground buried object protector 10 according to this modified example. As with the underground buried object protector 10 according to one embodiment of the present invention (see Figure 5), the high-strength fiber sheet 16 comes into contact with the groove 62 of the blade 60 before the entire underground buried object protector 10 is cut by the blade 60. At this time, since the high-strength fiber sheet 16 is separated from the highly processed and hardened steel plate 14, the blade 60 of the concrete cutter is likely to get caught in the mesh of the high-strength fiber sheet 16. This can improve the cut resistance of the high-strength fiber sheet 16.

The spacer in this modified example is not limited to a frame shape. For example, it may be in the shape of a lattice, a pair of rods, or a long flat plate.

(Third Modification)
Next, a third modified example of the embodiment of the present invention will be described.

Figure 11 is a vertical cross-sectional view of the underground buried object protector 10, showing a third modified example of the underground buried object protector 10 shown in Figure 1. In the modified example shown in Figure 11, the configuration of the underground buried object protector 10 has been changed as follows compared to the second modified example.

That is, the underground buried object protector 10 shown in FIG. 11 further includes a waterproof cover material 82 that covers the upper surface of the highly work-hardened steel plate 14. This cover material 82 prevents contact between the highly work-hardened steel plate 14 and water that has entered the inside of the box body 12, for example, between the upper cover 18 and the lower box 20, and suppresses rusting of the highly work-hardened steel plate 14. In the second modified example, the cover material 82 is formed in a bag shape and contains the highly work-hardened steel plate 14 inside. That is, the cover material 82 according to the second modified example covers the entire surface of the highly work-hardened steel plate 14. Note that the opening of the bag-shaped cover material 82 may be sealed by welding or the like after the highly work-hardened steel plate 14 is contained therein, and may have a structure in which an opening remains in the center of the lower surface, for example.

The cover material 82 may be made of any material that can prevent the highly work-hardened steel plate 14 from rusting due to water or the like that has penetrated into the box body 12, but as an example it is made of OPP (Originated Polypropylene). In particular, for a bag-shaped cover material 82 with an insertion opening smaller than one side of the highly work-hardened steel plate 14 (for example, a structure in which an opening remains in the center of the underside as described above), it is preferable to use OPP, which is a biaxially stretched material.

Here, if rust occurs on the top surface of the highly work-hardened steel plate 14, the highly work-hardened steel plate 14 and the high-strength fiber sheet 16 may adhere to each other. In this case, even if the highly work-hardened steel plate 14 comes into contact with the blade 60 of the concrete cutter, the high-strength fiber sheet 16 will not easily become entangled with the blade 60 of the concrete cutter.

In this modified example, the upper surface of the highly work-hardened steel plate 14 is covered with the cover material 82, thereby suppressing rusting on the upper surface of the highly work-hardened steel plate 14. This suppresses rusting of the highly work-hardened steel plate 14 and adhesion between the highly work-hardened steel plate 14 and the high-strength fiber sheet 16. This allows the cut resistance of the high-strength fiber sheet 16 to be maintained for a long period of time.

The cover material 82 may be in any shape as long as it can prevent rusting of the highly work-hardened steel plate 14 from water or other substances that may have entered the box body 12. For example, the cover material 82 is not limited to the bag-shaped configuration described above, and may be in the form of a single sheet. In this case, the sheet-shaped cover material 82 may be configured to cover the upper surface of the highly work-hardened steel plate 14 with its peripheral portion woven into the lower surface side of the highly work-hardened steel plate 14.

In addition, in the third modified example of the present invention, the spacer 80 may not be provided, and a high-strength fiber sheet 16 may be placed on the upper surface of the highly work-hardened steel plate 14 covered with the cover material 82. Even in this case, the above-mentioned cover material 82 can further improve the reliability of the underground buried object protection equipment 10 compared to one embodiment of the present invention.

In addition, in the underground buried object protection equipment 10 according to the above embodiment, the second modified example, and the third modified example, the peripheral wall of the lower box 20 may be positioned outside the peripheral wall 24 of the upper cover 18, as in the underground buried object protection equipment 10 according to the modified example shown in FIG. 7.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and can of course be modified in various ways without departing from the spirit of the invention.

10 Underground buried object protection equipment 12 Box body 14 Highly work-hardened steel plate 16 High-strength fiber sheet 18 Top cover 20 Bottom box 22 Top plate 24 Peripheral wall 26 Bottom plate 28 Peripheral wall 30 Protrusion 32 Through hole 50 Concrete trough 52 Buried object 54 River sand 60 Blade 62 Groove 70 Chisel 80 Spacer 82 Cover material

Claims (10)

A box body having an upper lid and a lower box;
A highly work-hardened steel plate laid on the inner bottom surface of the lower box;
a high-strength fiber sheet laid on an upper surface of the highly work-hardened steel plate, the high-strength fiber sheet being formed by weaving fibers and having a mesh shape with gaps surrounded by the fibers ;
Underground buried object protection equipment equipped with The upper cover and the lower box are formed of hot-dip Zn-Al-Mg alloy-plated steel sheets.
The underground buried object protection equipment according to claim 1. The high work-hardening steel plate is a high carbon and high manganese steel plate.
The underground buried object protection equipment according to claim 1 or 2. The high-strength fiber sheet is formed of aramid fiber, synthetic fiber mixed with aramid fiber, or fiber made of polypropylene, polystyrene, or polycarbonate.
The underground buried object protective equipment according to any one of claims 1 to 3. The upper cover has a top plate and a peripheral wall formed on a periphery of the top plate and extending downward from the top plate,
The lower box has a bottom plate and a peripheral wall formed on a periphery of the bottom plate and extending upward from the bottom plate,
When the upper cover is attached to the lower box, the peripheral wall of the lower box is located outside the peripheral wall of the upper cover,
A protrusion is formed on the upper end of the peripheral wall of the lower box, the protrusion protruding above the top plate .
The underground buried object protective equipment according to any one of claims 1 to 4. The high work-hardening steel plate is formed into an overall curved shape so as to form a single convex shape on the upper side.
The underground buried object protective equipment according to any one of claims 1 to 5. The box body, the highly work-hardened steel plate, and the high-strength fiber sheet are included.
The underground buried object protective equipment according to any one of claims 1 to 6. The invention further includes a spacer disposed between the highly work-hardened steel plate and the high-strength fiber sheet.
The underground buried object protective equipment according to any one of claims 1 to 7. The spacer is a frame body that conforms to the outer shape of the high work-hardening steel plate,
The high-strength fiber sheet is spaced from the upper surface of the high work-hardening steel plate inside the frame of the spacer.
The underground buried object protection equipment according to claim 8. Further provided is a waterproof cover covering the upper surface of the highly work-hardened steel plate.
The underground buried object protective equipment according to any one of claims 1 to 9.