JP7324399B2 - pavement structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pavement structure that is applied when burying equipment for melting snow or the like.

Various facilities are sometimes buried in roads for various purposes. For example, in areas where a lot of snow accumulates, snow-melting facilities are buried to remove accumulated snow or prevent freezing.

Snow-melting equipment includes water spraying nozzles buried in the center of two-lane roads and flowing it down the road shoulders, as well as water spraying nozzles embedded in the surface layer of pavement cross-sections that bleed water onto the road surface. A known method is to heat the road surface by energizing a heater buried inside or by passing groundwater through a pipe buried in the surface layer.

All of these snow-melting equipment can ensure driving safety in winter by removing accumulated snow or preventing the road surface from freezing. Damage due to the load of passing vehicles must be prevented by increasing the thickness and strength of the surface layer.

Here, Patent Document 1 discloses a configuration in which at least a part of the upper pavement layer is made of mortar containing resin short fibers as a base layer, and an embedded object is embedded in the base layer. According to this configuration, since the short resin fibers improve the crack resistance of the base layer, the thickness of the upper pavement layer can be reduced. It is possible to efficiently transfer the heat to the road surface.

JP 2018-53510 A

However, in the structure described in Patent Document 1, the base layer made of mortar containing resin short fibers is horizontally divided by the buried object in the depth range where the buried object is buried, so the tensile force is applied in the horizontal direction. In that case, the function as a bending resistance element is reduced by the depth range described above, and there is a possibility that the bending moment due to the load applied to the road surface may not be sufficiently resisted. was occurring.

This means that the crack-resistant function of the short resin fibers is not exerted in the depth range where the embedded object is embedded in the base layer. Since the depth is limited to the depth range from the top of the buried object to the road surface, an unexpected tensile stress is generated in this depth range, cracking occurs and progresses from the top of the buried object to the road surface, and as a result, the buried object There is also a problem that an unexpected load may be applied to the buried object, causing damage to the buried object.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pavement structure capable of preventing damage to buried objects without increasing the thickness of the surface layer.

In order to achieve the above object, the pavement structure according to the present invention has a surface layer whose upper surface is a road surface, which is arranged above the roadbed and is an object that is prevented from being damaged by the load applied to the road surface. In a pavement structure in which an object to be protected is embedded in the surface layer ,
Tensile resistance means are arranged in a depth range within the surface layer, the upper limit being the top end of the protection object and the lower limit being the lower boundary of the protection object, in such a manner as to extend to both sides of the protection object, In the tensile resistance means, a tensile force is generated in the tensile resistance means by an applied load on the road surface, and the tensile force acts on the surface layer as a compression reaction force. An arch mechanism is formed in the surface layer to cover the object .

Further, in the pavement structure according to the present invention, the surface layer is formed of a material capable of shear resistance, and the tensile resistance material is formed so that the load transmission between the surface layer and the tensile resistance means is performed through their adhesion. It constitutes the means.

Further, in the pavement structure according to the present invention, the surface layer is formed of fiber-mixed mortar.

Further, in the pavement structure according to the present invention, the tensile resistance means is composed of a grid-like resistance member, a sheet-like resistance member, a bar-like resistance member, or a hook-attached resistance member in which hooks are provided at each end of a bar-like portion. be.

Further, in the pavement structure according to the present invention, the surface layer is formed of a material capable of resisting compression, and the pressure between the surface layer and the tensile resistance means is provided via a bearing means provided in the vicinity of the tip of the tensile resistance means. is configured so that the load is transmitted.

In the pavement structure according to the present invention, the surface layer is composed of sand, clay, mortar that does not contain fiber, or cement-improved soil that does not contain fiber.

Further, in the pavement structure according to the present invention, the tensile resistance means is a rod-shaped resistance member, and the bearing pressure means is a plate-shaped resistance portion arranged orthogonally to the rod-shaped resistance member.

Further, in the pavement structure according to the present invention, the tensile resistance means is positioned below the object to be protected and is configured to extend continuously from one side to the other side of the object to be protected. be.

Further, in the pavement structure according to the present invention, the object to be protected is composed of a housing and equipment to be protected arranged in the housing, and the tensile resistance means is configured to extend from each side surface of the housing. It is what I did.

In the pavement structure according to the present invention, the object to be protected is embedded in the surface layer arranged above the roadbed. The tension resistance means is constructed such that a load on the road surface causes a tensile force to be generated in the tension resistance means, and the tensile force acts on the surface layer as a compression reaction force.

That is, when a vertical load is applied to the road surface, the surface layer tries to bulge laterally due to the applied load. The load can be transmitted not only downward but also obliquely downward as a compressive force.

In such a situation, if the tensile resistance means are arranged to extend to both sides of the object to be protected, a tensile force is generated in the tensile resistance means by the above-mentioned compressive force, and the tensile force acts on the surface layer as a compression reaction force. At the same time, the compressive reaction force becomes horizontal reaction force on the surface layer, forming an arch mechanism similar to that observed in reinforced concrete beams.

Therefore, if the loading point is set above the object to be protected, the arch mechanism will be formed in the surface layer so as to cover the object to be protected. Flow diagonally downward to avoid objects.

Therefore, even without increasing the thickness of the surface layer, it is possible to prevent the object to be protected from being damaged by the load of the road surface, and from the viewpoint that the surface layer is subjected to bending deformation due to the load of the road surface, the load On the other hand, the surface layer can resist bending with its entire thickness or with a cross-sectional thickness close to it, and when the surface layer is composed of a material with high shear resistance function, it fully exhibits the tensile resistance function that it also has. becomes possible.

Pavement structures are mainly intended for pavement structures for roads, but they can be used for any purpose other than roads as long as the load from running vehicles is applied to the road surface, such as parking lot pavement. Structure is also included.

It is sufficient for the surface layer to be placed above the roadbed, and in addition to the case where the surface layer is directly laminated on the roadbed, a form in which the surface layer is laminated with an intermediate layer such as a base layer interposed is also included.

A typical example of an object to be protected is a form in which it extends continuously in one direction, if the pavement structure is for a road, in the axial direction of the road, but a form in which it is discretely arranged in one direction is also included.

Items to be protected include cables and coils for power supply, wireless power supply, communication, etc., heating wires and pipes for snow melting, and piping for fluid transportation for cooling and heating. However, its use and form are arbitrary.

As described above, the load on the road surface is transmitted obliquely downward due to the arch mechanism, and the downward transmission is reduced. does not have to be

As for the structure for transmitting the load between the surface layer and the tensile resistance means, there are two main types: adhesion between the surface layer and the tensile resistance means, and bearing means provided near the tip of the tensile resistance means. separated.

Here, the former is based on the premise that the surface layer is formed of a material capable of shearing resistance, such as fiber-mixed mortar. A form comprising a member, a rod-shaped resistance member, or a resistance member with hooks provided with hooks at each end of the rod-shaped portion is encompassed.

On the other hand, the latter is based on the premise that the surface layer is made of a material that can resist compression, such as sand, clay, mortar that does not contain fibers, cement-improved soil that does not contain fibers, etc., and its composition is A typical example is a form in which the tensile resistance means is composed of a rod-shaped member and a bearing plate as a bearing means is attached to the tip thereof.

If the material forming the surface layer is shear resistant and compressive resistant, either transmission mechanism may be adopted, or the two transmission mechanisms may be mixed. .

For example, when the surface layer is formed of fiber-mixed mortar, and taking advantage of the fact that the fiber-mixed mortar is a material that can resist compression, if a bearing plate is attached to the tip of the rod-shaped member, the peripheral surface of the rod-shaped member can be The load is transmitted by the adhesion to the surface layer, and the load is transmitted by the bearing pressure on the bearing plate.

Since it becomes difficult to form an arch mechanism in the surface layer in a manner that covers the object to be protected at a position shallower than the depth where the object to be protected is buried, the tensile resistance means is limited to the top of the object to be protected. Shall be positioned in a depth range bounded by the lower boundary of the superficial layer.

Here, the tensile resistance means may have any configuration as long as it is arranged so as to extend on both sides of the object to be protected. It may be configured to extend continuously from one side to the other side, or the protected object may be composed of the enclosure and the equipment to be protected placed in the enclosure, and may extend from each side of the enclosure. may be configured.

In the latter case, the housing needs to have tensile strength so that the tensile force is transmitted between the two tensile resistance means. can be expected.

1 is a vertical sectional view of a pavement structure 1 according to this embodiment; FIG. Overall horizontal sectional view along line AA. Explanatory drawing which showed the effect|action of the pavement structure 1 which concerns on this embodiment. Explanatory drawing which showed another effect|action of the pavement structure 1 which concerns on this embodiment. The perspective view which showed the pavement structure which concerns on a modification. Explanatory drawing which showed the vertical sectional view which showed the pavement structure which concerns on another modification, and its effect|action. Explanatory drawing which showed the pavement structure which concerns on another modification, and its effect|action.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the pavement structure which concerns on this invention is described with reference to an accompanying drawing.

FIG. 1 is a vertical sectional view showing a pavement structure 1 according to this embodiment, and FIG. 2 is an overall horizontal sectional view along line AA. As can be seen from these figures, the pavement structure 1 has a surface layer 3 having a road surface 2 on its upper surface, which is laminated on a roadbed 4, and an object 5 to be protected is embedded in the surface layer 3. As shown in FIG.

The roadbed 4 is layered on a roadbed (not shown) and can be constructed of a crusher run, and the object to be protected 5 is housed in a circular steel pipe 5a as a housing and its internal space. It consists of equipment 5b to be protected.

The equipment to be protected 5b may be composed of cables and coils for power supply, wireless power supply, communication, etc., heating wires and pipes for melting snow, and piping for fluid transportation for cooling and heating. Just do it.

The surface layer 3 is made of fiber-mixed mortar as a material capable of shear resistance, and resistance members 6 with hooks as tensile resistance means are embedded in the surface layer so as to extend to both sides of the object 5 to be protected. There is.

The fiber-mixed mortar may be produced by adding fibers (short fibers) having a length of several mm to several tens of mm to fresh mortar kneaded according to an appropriate composition and further kneading the mixture.

The short fibers can be appropriately selected from metal fibers, carbon fibers, organic fibers, etc., and the metal fibers can be steel fibers, stainless steel fibers, amorphous alloy fibers, etc., and the organic fibers are It can be composed of polyamide, polypropylene (PP), polyvinyl alcohol or vinylon (PVA), polyethylene (PE), polyester, polyethylene terephthalate (PET), and the like.

The hooked resistance member 6 is formed by providing hooks 6b, 6b at each end of a rod-shaped portion 6a, and can be constructed by bending each end of a deformed reinforcing bar, for example.

Such a resistance member 6 with a hook is located below the object 5 to be protected in particular in the depth range D with the top end of the object 5 as the upper limit and the lower boundary of the surface layer 3 as the lower limit in this embodiment. It is positioned and configured to extend continuously from one side of the protected object to the other.

Here, the resistance member 6 with hooks is loaded on the road surface 2 by performing load transmission through adhesion between the surface layer 3 and the rod-shaped portion 6a and bearing pressure between the surface layer 3 and the hooks 6b, 6b. When a load is transmitted through the surface layer 3 as a compressive force, a tensile force is generated in the hooked resistance member, and the tensile force acts on the surface layer 3 as a compression reaction force.

As shown in FIG. 2, the resistance members 6 with hooks are arranged discretely at predetermined intervals along the embedding direction of the object 5 to be protected.

In the pavement structure 1 according to the present embodiment, as shown in FIG. 3A, when a vertical load is applied to the road surface 2 through the tires 31 of an automobile, the surface layer 3 is laterally bent by the applied load. It tries to inflate, but because the surface layer 3 extends horizontally, the lateral deformation is restrained, so the applied load can be transmitted not only downward but also obliquely downward as a compressive force. .

In this situation, since the resistance members 6 with hooks are arranged so as to extend on both sides of the object 5 to be protected, the compression force described above causes the resistance members with hooks to move between the surface layer 3 and the rod-like portions 6a. A tensile force is generated through load transmission due to the adhesion of the surface layer 3 and the bearing pressure between the hooks 6b and 6b, and the tensile force acts on the surface layer 3 as a compression reaction force. The force becomes a horizontal reaction force, and an arch mechanism 32 similar to that observed in a reinforced concrete beam is formed as shown in FIG.

Therefore, if the loading point is set above the object to be protected 5 , the arch mechanism 32 will be formed in the surface layer 3 so as to cover the object to be protected 5 . As for the flow of air, the obliquely downward flow along the arch mechanism 32 is dominant.

As described above, according to the pavement structure 1 according to the present embodiment, the resistance members 6 with hooks are arranged in the surface layer 3 so as to extend to both sides of the object 5 to be protected, and the resistance members 6 with hooks are Since a tensile force is generated in the resistance member with hooks due to the applied load on the road surface 2 and the tensile force acts on the surface layer 3 as a compression reaction force, the arch mechanism 32 covers the object 5 to be protected. The load on the road surface 2 formed in the surface layer 3 flows obliquely downward as a compressive force so as to avoid the object 5 to be protected. It is possible to prevent the object 5 from being damaged.

In addition, the surface layer 3 is subjected to bending deformation due to the load applied to the road surface 2, but when the object 5 to be protected is simply placed on the roadbed 4 as in the conventional art, the surface layer 3 is deeper than the top of the object 5 to be protected. In the range, as shown in FIG. 4(a), the surface layer 3 is horizontally divided by the object to be protected, and the tensile force is not continuous. Only a shallow region above the top of the protected object 5 can resist the tensile force, and a crack 41 is generated in a deep region below that because the tensile force cannot be resisted.

In other words, in the conventional art, only the thickness range T' shallower than the top of the object to be protected 5 in the surface layer 3 having the thickness T can contribute to the suppression of bending deformation. , the tensile resistance function that the fiber-mixed mortar has together with the shear resistance function is not exhibited, and an unexpected tensile stress is generated even in the thickness range T', and the crack 41 further progresses toward the road surface 2. As a result, an unexpected load may be applied to the object to be protected 5, causing damage. However, according to the pavement structure 1 according to the present embodiment, as shown in FIG. In order to resist tension due to bending, the surface layer 3 can resist bending at its full thickness T or at a cross-sectional thickness close to it, thus making it possible to fully exhibit the tensile resistance function of the fiber-mixed mortar. .

In this embodiment, the object to be protected 5 is composed of the circular steel pipe 5a as a housing and the equipment to be protected 5b housed in the inner space of the circular steel pipe 5a. Since the object 5 is prevented from being damaged, it is not necessary to house the equipment 5b to be protected in a strong housing such as the circular steel pipe 5a. For example, it may be housed in a resin tube. Furthermore, it is also possible to omit the housing and bury only the equipment 5b to be protected.

Further, in the present embodiment, fiber-mixed mortar is used as a shear-resistant material, but instead of this, for example, cement-improved soil containing short fibers can be used.

In addition, in this embodiment, the tensile resistance means is composed of the hooked resistance member 6, but instead of this, as shown in FIGS. A sheet-like resistance member 52 and a rod-like resistance member 53 may be used.

Here, the grid-like resistance member 51 and the sheet-like resistance member 52 can be made of polyester resin, for example, and the rod-like resistance member 53 can be made of deformed reinforcing bars. It should be transmitted. Specifically, the grid-like resistance member 51 can be made of expanded metal or grid-like FRP commercially available under the name of "Nefmac" (registered trademark).

In the present embodiment, the surface layer 3 is made of fiber-containing mortar, which is a material capable of shear resistance. It is possible to adopt load transmission by a bearing means provided in the vicinity of the tip of the tensile resistance means instead of the load transmission by the adhesion of the tension resistance means.

The pavement structure 61 shown in FIG. 6(a) is formed by stacking a surface layer 63 on which the upper surface is the road surface 2 on the roadbed 4, and an object to be protected 5 is embedded in the surface layer 63. 63 is made of a material capable of resisting compression, and in the surface layer, a rod-shaped resistance member as a tensile resistance means is constructed of round steel 66, and the round steel is placed on both sides of the object 5 to be protected. Angle steel 67 is attached to the vicinity of each end of the round steel by welding or the like. Particularly in this embodiment, it is positioned below the object to be protected 5 and is configured to extend continuously from one side of the object to be protected to the other side.

Here, in the angle steel 67, the flange 68 as a plate-like resistance portion orthogonal to the material axis of the round steel 66 functions as a bearing means for transmitting the load between the surface layer 63 and the round steel 66. ing.

The compression-resistant material may be appropriately selected from sand, clay, mortar containing no fibers, cement-improved soil containing no fibers, and the like.

The round steel 66 and the angle steels 67, 67 may be arranged discretely at predetermined intervals along the direction in which the object to be protected 5 is embedded.

In the pavement structure 61 according to this modified example, when a vertical load is applied to the road surface 2 through the tires 31 of the vehicle as shown in FIG. A steel 66 is placed and an angle steel 67 having a flange 68 positioned perpendicular to the material axis is attached to the tip of the round steel. A similar compressive force causes a tensile force through load transmission due to bearing pressure at the flange 68, and the tensile force acts on the surface layer 63 as a compressive reaction force, and the compressive reaction force acts on the surface layer 63 horizontally. The reaction force forms an arch mechanism 32' similar to that observed in reinforced concrete beams.

Therefore, if the loading point is set above the object to be protected 5, the arch mechanism 32' will be formed in the surface layer 63 so as to cover the object to be protected 5, so that the load is placed on the road surface 2. The load flow is predominantly diagonally downward along the arch mechanism 32'.

Therefore, according to this modified example, the arch mechanism 32' is formed in the surface layer 63 in such a manner as to cover the object 5 to be protected, as in the case of the present embodiment, so that the object 5 to be protected is prevented from being damaged by the load applied to the road surface 2. However, since these are generally the same as in the above-described embodiment, the description thereof will be omitted here.

In addition, in the present embodiment and its modifications, the hooked resistance member 6, the grid-shaped resistance member 51, the sheet-shaped resistance member 52, the bar-shaped resistance member 53, or the round steel 66, which are tensile resistance means, are all attached to the object 5 to be protected. and extend continuously from one side of the protected object to the other. In addition to the object equipment, hooked resistance members, grid-shaped resistance members, sheet-shaped resistance members, bar-shaped resistance members, or round bars as tensile resistance means may be configured to extend from each side of the housing. good.

FIG. 7(a) shows an object to be protected 5' composed of a square steel pipe 5c as a housing and equipment to be protected 5b accommodated in the inner space thereof, and the object to be protected is buried in the surface layer 3, and the tip is 4(b) shows a configuration in which hooked resistance members 71 having hooks provided at the ends are extended from each side of the rectangular steel pipe 5c. FIG. It shows a configuration extending from each side surface of the square steel pipe 5c.

In these configurations, it is necessary to give the rectangular steel pipes a corresponding tensile strength so that the hooked resistance members 71, 71 and the round steels 66, 66 can transmit the tensile force to each other through the rectangular steel pipes 5c. If the resistance members 71, 71 with hooks and the round steels 66, 66 are preliminarily attached to the square steel pipe 5c, it is possible to expect an improvement in workability during construction.

Note that the operational effects in FIG. 7 are substantially the same as those of the embodiment and its modification, and therefore the description thereof is omitted here.

1,61 Pavement structure 2,63 Road surface (upper surface)
3 surface layer 4 roadbed 5, 5' object to be protected 5a, 5c housing 5b equipment to be protected 6 resistance member with hook (tensile resistance means)
6a rod-shaped portion 6b hook 32 arch mechanism 51 grid-like resistance member (tensile resistance means)
52 sheet resistance member (tensile resistance means)
53 Rod-shaped resistance member (tensile resistance means)
66 Round steel (tensile resistance means, bar resistance member)
68 flange (bearing means, plate-like resistance part)
71 resistance member with hook

Claims (9)

A pavement structure in which a surface layer whose upper surface is a road surface is arranged above the roadbed and an object to be protected as an object to be prevented from being damaged by the load of the road surface is buried in the surface layer ,
Tensile resistance means are arranged in a depth range within the surface layer, the upper limit being the top end of the protection object and the lower limit being the lower boundary of the protection object, in such a manner as to extend to both sides of the protection object, In the tensile resistance means, a tensile force is generated in the tensile resistance means by an applied load on the road surface, and the tensile force acts on the surface layer as a compression reaction force. A pavement structure, characterized in that an arch mechanism is formed in said surface layer in such a way as to cover an object . 2. The pavement according to claim 1, wherein said surface layer is formed of a shear-resistant material and said tensile resistance means is constructed such that load transmission between said surface layer and said tensile resistance means is effected through their attachment. structure. 3. The pavement structure according to claim 2, wherein said surface layer is made of mortar mixed with fibers. 4. The pavement structure according to claim 2 or 3, wherein the tensile resistance means is composed of a grid-like resistance member, a sheet-like resistance member, a bar-like resistance member, or a hook-attached resistance member having a hook provided at each end of the bar-like portion. The surface layer is made of a material capable of resisting compression, and a load is transmitted between the surface layer and the tensile resistance means through bearing means provided near the tip of the tensile resistance means. A pavement structure according to claim 1. 6. The pavement structure according to claim 5, wherein the surface layer is composed of sand, clay, fiber-free mortar, or fiber-free cement-improved soil. 7. The pavement structure according to claim 5 or 6, wherein said tensile resistance means is composed of a rod-shaped resistance member, and said pressure-bearing means is composed of a plate-shaped resistance portion arranged orthogonally to said rod-shaped resistance member. 8. The tensile resistance means according to any one of claims 1 to 7, wherein the tensile resistance means is positioned below the object to be protected and is configured to extend continuously from one side to the other side of the object to be protected. pavement structure. 8. The object to be protected according to any one of claims 1 to 7, wherein the object to be protected is composed of a housing and equipment to be protected arranged in the housing, and the tensile resistance means is constructed so as to extend from each side surface of the housing. 1. The pavement structure of claim 1.

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