JP6673650B2 - Pavement method and pavement structure - Google Patents

Description

  The present invention relates to a pavement method and a pavement structure using a pavement block.

  Among the pavement structures used for roads and parking lots, for block-based pavement, blocks such as concrete flat plates and interlocking blocks are used as pavement materials. Among the block-type pavements, the pavement structure using the interlocking block for the pavement layer is particularly durable and safe by appropriately selecting the shape, dimensions, laying pattern, color tone and surface texture of the interlocking block. It is possible to realize a pavement excellent in easiness, comfort and landscape. In a pavement structure using an interlocking block, when a wheel load of a vehicle or the like is applied, sand (joint sand) filled in joints between the interlocking blocks exhibits an interlocking effect between the interlocking blocks. . The load can be dispersed by this meshing effect.

Patent Literature 1 discloses a technique in which a reinforcing layer made of a geogrid is provided on a roadbed, a roadbed layer is formed thereon, and a pavement block is laid on the roadbed layer. As a result, even if a certain degree of subsidence occurs on a soft roadbed, the reinforcement effect is exerted. Further, in Patent Document 2, a surface layer is formed by a porous concrete block, a cushion layer is provided below the surface layer, a base layer made of a porous asphalt treatment mixture is provided below the cushion layer, and below the base layer, and A technique for forming a roadbed made of a cement-stabilized material having a water permeability of 1.0 × 10 ^{−2 to} 1.0 × 10 ⁻⁵ (cm / sec) above a roadbed is disclosed. As a result, a permeable pavement structure that can be applied to a road with a large traffic volume is realized.

JP 2010-281080 A JP 2001-011810 A

  When block-type pavement such as interlocking blocks, concrete slabs, natural stones, tiles, bricks, etc. is to be constructed by dry construction method using joint sand or laying sand, steps and settlements will occur after operation, resulting in people and automobiles. Traffic may be impeded. The causes of such steps and settlements are that the load dispersion performance is reduced by applying products with large block dimensions, and that design, construction, and installation of granular roadbeds such as crusher ores and grain crushed stones. The quality and thickness of the sand may be excessive (the appropriate thickness is 20 to 30 mm depending on the application). In addition, the quality of the joint sand may be a cause.

  On the other hand, as a measure for reinforcing interlocking block pavement, a construction method using a reinforcing plate is known. The reinforcing plate is a plate made of plastic, which is placed on sand and inserted into the four corners of the block, and has an effect of assisting load distribution of a large-sized interlocking block pavement.

  However, the following problems exist in the reinforcing plate. That is, in the method using the reinforcing plate, the reinforcing plates have to be laid one by one manually at the four corners of the block, so that the construction takes more time and effort than the method using no reinforcing plate. As a result, the construction cost increases, and the material cost of the reinforcing plate also increases. In addition, the use of the reinforcing plate may increase the joint width between the blocks, and reduce the load distribution function. The reinforcement plate is used to reinforce the load distribution effect of the large block.However, the reinforcement of the load support effect may be insufficient at the center of the block without the reinforcement plate. As a result, there is a fear that the block may be broken. Furthermore, there is a problem that it cannot be applied to a rectangular block having a small size such as a size of 100 mm × 200 mm, which is most frequently used in Japan.

  Since the technology described in Patent Document 1 is assumed to be applied to a soft roadbed, it has been completely confirmed by a demonstration experiment and the like how to prevent a step and a settlement after the operation on the block pavement. Absent. In addition, the geogrid has a great influence on the deflection characteristics of the block pavement as the position of use becomes higher. That is, as the position where the geogrid is used is on the subgrade, in the subgrade, or on the subgrade, a problem such as a pumping phenomenon may occur, which may have an adverse effect rather than a reinforcing effect. For this reason, it is necessary to limit the size and specification to which the geogrid can be applied, but these points have not been confirmed in Patent Document 1. Furthermore, when using it on a roadbed, no consideration is taken into consideration in construction. Further, the technique described in Patent Document 2 aims at realizing a water-permeable pavement structure, and therefore cannot solve the problem in block-based pavement.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a pavement method and a pavement structure capable of effectively preventing a step or settlement specific to block pavement.

  (1) In order to achieve the above object, the present invention has taken the following measures. That is, the pavement method of the present invention is a pavement method using a pavement block, wherein a step of forming a subgrade layer on a subgrade, a step of forming a spread layer on the subgrade layer, and Laying a two-way stretched geogrid composed of vertical strands and horizontal strands having a length determined from the maximum particle size of the vertical grain and nodes of the vertical strands and the horizontal strands on the sand layer, Laying a paving block on the geogrid.

  In this way, a two-way stretch type geogrid composed of vertical strands and horizontal strands having a length determined from the maximum particle size of the bed sand of the bed sand layer and nodes of the vertical strands and the horizontal strands is placed on the bed sand layer. Lay it. Thus, when a load (for example, traffic load) is applied to the pavement block, the geogrid is pushed down in the direction of gravity by the uniformly distributed load, and at this time, a tensile stress is generated, and sand particles of the bed sand (and joint sand) are generated. In between, the frictional force and the interlocking effect, that is, the effect that the movement of the sand particles is restricted by the geogrid is exhibited. As a result, the pavement block, the bed sand (and joint sand), and the geogrid are integrated, and can withstand the load. In addition, since the geogrid is laid in a wide area, the distribution range of the load can be widened as compared with a structure without a geogrid or other reinforcing methods. As a result, the deflection of the pavement surface is reduced, and the stress generated in the sand layer and the roadbed layer is reduced, so that it is possible to suppress the steps and settlements caused by the pavement blocks.

  (2) In the pavement method according to the present invention, the nodes of the geogrid are thicker than the vertical strands and the horizontal strands and have a convex shape.

  As described above, since the nodes of the geogrid are thicker than the vertical strands and the horizontal strands, the strength of the nodes can be increased, and the grid structure of the geogrid is maintained even when tensile stress occurs. It becomes possible. In addition, since the node has a convex shape, it is possible to prevent interlayer slip between the geogrid and the pavement block.

  (3) In the paving method of the present invention, the thickness of the vertical strand and the horizontal strand is 1.0 mm or more and 3.0 mm or less, and the node is 2.0 mm or more and 4.0 mm or less. It is characterized by the following.

  Thus, the thickness of the vertical strand and the horizontal strand is 1.0 mm or more and 3.0 mm or less. When the thickness of the vertical strands and the horizontal strands is large, the deflection generated on the block pavement becomes large, and there is a concern about a ponbing phenomenon in which joint sand and bed sand are ejected. When the thickness is 0 mm or more and 3.0 mm or less, the pumping phenomenon can be prevented. In addition, the nodal point is 2.0 mm or more and 4.0 mm or less. As a result, it is possible to increase the strength of the node, and it is possible to maintain the grid structure of the geogrid even when tensile stress occurs.

  (4) Also, the paving method of the present invention may include laying the paving block so that a joint between one geogrid and another geogrid is always located immediately below the paving block. Features.

  In this way, the paving blocks are laid so that the joint between one geogrid and the other geogrid is always located immediately below the paving blocks. Therefore, the joint between one geogrid and another geogrid does not match. This makes it possible to prevent the paving block from shifting, stepping and sinking.

  (5) Further, the pavement structure of the present invention is a pavement structure using a pavement block, wherein a pavement layer formed on a subgrade, a pavement layer formed on the subbase layer, and a pavement layer formed on the pavement layer Laminated in the vertical direction and the horizontal strands having a length determined from the maximum particle size of the bed sand of the bed sand layer, and a two-way stretch type geogrid composed of nodes of the vertical strands and the horizontal strands, And a paving block laid on the geogrid.

  In this way, a two-way stretch type geogrid composed of vertical strands and horizontal strands having a length determined from the maximum particle size of the bed sand of the bed sand layer and nodes of the vertical strands and the horizontal strands is placed on the bed sand layer. Lay it. Thus, when a load (for example, traffic load) is applied to the pavement block, the geogrid is pushed down in the direction of gravity by the uniformly distributed load, and at this time, a tensile stress is generated, and sand particles of the bed sand (and joint sand) are generated. In between, the frictional force and the interlocking effect, that is, the effect that the movement of the sand particles is restricted by the geogrid is exhibited. As a result, the pavement block, the bed sand (and joint sand), and the geogrid are integrated, and can withstand the load. In addition, since the geogrid is laid in a wide area, the distribution range of the load can be widened as compared with a structure without a geogrid or other reinforcing methods. As a result, the deflection of the pavement surface is reduced, and the stress generated in the sand layer and the roadbed layer is reduced, so that it is possible to suppress the steps and settlements caused by the pavement blocks.

  According to the present invention, when a load (for example, a traffic load) is applied to a pavement block, the geogrid is pushed down in the direction of gravity by an evenly distributed load, and at this time, a tensile stress is generated, and sand (and joint sand) is generated. A frictional force and an interlocking effect, that is, an effect in which the movement of the sand particles is constrained by the geogrid is exerted on the sand particles. As a result, the pavement block, the bed sand (and joint sand), and the geogrid are integrated, and can withstand the load. In addition, since the geogrid is laid in a wide area, the distribution range of the load can be widened as compared with a structure without a geogrid or other reinforcing methods. As a result, the deflection of the pavement surface is reduced, and the stress generated in the sand layer and the roadbed layer is reduced, so that it is possible to suppress the steps and settlements caused by the pavement blocks.

It is a sectional view showing the schematic structure of the pavement structure concerning this embodiment. It is a top view of a geogrid. It is a conceptual diagram showing signs that a geogrid and sand particles receive a load and produce an interlocking effect. It is a key map showing signs that a pavement structure concerning this embodiment receives a load. It is a figure which shows the load dispersion effect in the pavement structure in which the reinforcement method is not performed. It is a figure showing the load distribution effect in the pavement structure using reinforcement board 13. It is a graph which shows the measurement result of the amount of deflection right under. It is a graph which shows the measurement result of a deflection ratio. It is a graph which shows the change of the amount of deflection with respect to a load. It is a figure which shows the load transmission range in case a reinforcement method is not performed, and the amount of settlement. It is a figure which shows the load transmission range at the time of using a reinforcement plate, and the amount of settlement. It is a figure which shows the load transmission range and sinking amount at the time of using a geogrid. It is a figure showing the state where the geogrid was cut along the width of the road and the width was adjusted. It is a figure showing signs that joints are formed between paving blocks 11.

  The present inventors have focused on geogrids laid on long slopes and steep embankments and having the effect of increasing their strength. It has been found that the problems described above can be prevented, and the present invention has been made.

  That is, the present invention relates to a paving method using a paving block, wherein a step of forming a roadbed layer on a subgrade, a step of forming a sandbed layer on the subgrade layer, and Laying, on the sand layer, a two-way stretch type geogrid composed of vertical strands and horizontal strands having a length determined from a diameter and nodes of the vertical strands and the horizontal strands, and And laying a paving block on the pavement.

  Thereby, the present inventors, while reducing the deflection of the pavement surface, reduce the stress generated in the sand layer and the roadbed layer, as a result, it is possible to suppress the step and settlement by the pavement block . Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[About pavement structure]
FIG. 1 is a sectional view showing a schematic configuration of a pavement structure according to the present embodiment. The pavement structure 1 according to the present embodiment includes a subgrade 3, a subgrade layer 5 formed on the subgrade 3, a sand layer 7 formed on the subgrade layer 5, and a geostructure laid on the sand layer 7. It is composed of a grid 9 and an interlocking block 11 as a pavement block laid on the geogrid 9.

  The geogrid 9 is a resin net called a geotextile, and has been conventionally used for reinforced earth walls, reinforced embankments, ground reinforcement, and the like. In the present embodiment, as shown in FIG. 1, a geogrid 9 is laid on the sand layer 7 and used to support the interlocking block 11.

[About Geogrid]
FIG. 2 is a plan view of the geogrid 9. The geogrid 9 is a two-way extending type, and is constituted by a vertical strand 9a and a horizontal strand 9b orthogonal thereto on a two-dimensional plane, and a node 9c which is an intersection of the vertical strand 9a and the horizontal strand 9. I have. The geogrid 9 according to the present embodiment can be defined as follows.
(1) The shape is a two-way stretching type.
(2) The size (length a of the vertical strand 9a × length b of the horizontal strand 9b) is “a = 19 to 38 mm, b = 28.5 to 47.5 mm”. This is determined from the size considering the maximum particle size of 4.75 mm or less as the quality of the bed sand applied to the block pavement. That is, the width and length of the mesh are determined as multiples of 4.75 mm from the relationship between the maximum particle size of the sand particles and the size of the mesh.
(3) If the thickness of the geogrid 9 increases, the deflection generated on the block pavement increases, which may cause a “pumping phenomenon” in which joint sand and floor sand erupt. The thickness was within 1.0 to 3.0 mm.
(4) In order to maintain the grid structure of the geogrid 9, the nodes 9c of the vertical and horizontal strands are made thicker (2.0 to 4.0 mm) than the strands. In addition, since sufficient joint strength (one strand) is required, the joint strength is set to 0.5 kN or more in both the vertical and horizontal directions.
(5) In order to prevent interlayer slip between the geogrid 9 and the interlocking block 11, the shape of the node 9c is made thicker than the vertical and horizontal strands 9a and 9b and is convex.
(6) Since a high tensile strength is required to withstand repeated traffic loads on the interlocking block 11, the tensile strength of the geogrid 9 is set to 10.0 kN / m or more in height and 20.0 kN / m in width. Above.
(7) Since a high elongational rigidity and a maximum tensile force are required in order to exhibit the load dispersion effect of the geogrid 9, the elongational rigidity is set to 20 kgf or more and the maximum tensile force is set to 0.5 kgf / cm or more.
(8) The material of the geogrid 9 is polypropylene, polyethylene, or the like.
(9) The width and length of the geogrid 9 are determined in consideration of workability. For example, it is assumed that the sheet is cut in advance to a width of 2 to 4 m, an extension of 100 to 200 m, or a certain size (100 to 200 cm in both length and width).
(10) The geogrid 9 can be applied to all block-based pavements constructed with joint sand and spread sand (including kneaded mortar).
(11) In addition, a geogrid is pasted on the surface of the interlocking block on the side of the sand (the lower surface of the interlocking block). May be laid. Thereby, it is possible to obtain the same effect as the case where the geogrid 9 is laid on the sand layer 7.

[Action of Geogrid]
FIG. 3 is a conceptual diagram showing how a geogrid and a sand particle receive a load to cause an interlocking effect, and FIG. 4 is a conceptual diagram showing how a pavement structure according to the present embodiment receives a load. . By laying the geogrid 9 on the upper surface of the sand layer 7, as shown in FIG. 4, the geogrid 9 is pushed down by the equally distributed load due to the traffic load, and at this time, a tensile stress (σt) is generated. As a result, an interlocking effect due to a frictional force between the sand particles (bed sand and joint sand), that is, an effect that the sand particles are restrained by the geogrid and do not move is exhibited. As a result, the interlocking block, the spread sand, the joint sand, and the geogrid can be integrated to counter the traffic load.

  As described above, the presence of the geogrid broadens the load distribution range as compared with a structure without the geogrid and other reinforcement methods. As a result, the deflection of the pavement surface is reduced, and the stress generated in the sand layer and the roadbed layer is reduced, so that the effect of suppressing steps and settlement is obtained.

[Load dispersion effect of geogrid]
Compare the load distribution effect of the pavement structure according to the present embodiment with the load distribution effect of the pavement structure not using the reinforcing method and the pavement structure using the reinforcing plate. FIG. 5 is a diagram illustrating a load dispersion effect in a pavement structure that has not been subjected to the reinforcing method. As shown in FIG. 5, the load is dispersed in a narrow range on the subgrade 3 via the sand layer 7 and the subbase layer 5, thereby increasing the vertical compressive strain (εZ ₁ ). FIG. 6 is a diagram showing a load distribution effect in a pavement structure using the reinforcing plate 13. As shown in FIG. 6, the load is widely distributed to the sand layer 7 and the subbase layer 5 via the reinforcing plate 13, and is also widely distributed to the subgrade 3, thereby generating a vertical compressive strain (εZ). ₂ ) becomes smaller. Therefore, it is considered that the pavement structure using the reinforcing plate 13 has a higher load dispersing effect than the pavement structure without the reinforcement method.

In contrast to these pavement structures, in the pavement structure according to the present embodiment shown in FIG. 4, since the geogrid 9 is provided, a load is applied by the geogrid 9 to a wide range of the sand layer 7. Then, it is dispersed over a wide range on the subgrade ₃ via the subbase layer 5, and the vertical compressive strain (εZ ₃ ) generated thereby is reduced. That is, the magnitude of the load dispersion effect is as follows in the order of the pavement structure according to the present embodiment shown in FIG. 4, the pavement structure using the reinforcing plate 13 shown in FIG. 6, and the pavement structure without the reinforcement method shown in FIG. 5. growing. In addition, the magnitude of the stress and the compressive strain (εZ) generated in the sand layer 7, the roadbed layer 5, and the subgrade 3 are determined by using a pavement structure without the reinforcing method shown in FIG. 5 and a reinforcing plate 13 shown in FIG. The size of the pavement structure becomes larger in the order of the pavement structure according to the present embodiment shown in FIG. The small vertical compressive strain (εZ) also has the effect of reducing “rutting” generated by vehicle traffic. Accordingly, it can be said that the pavement structure according to the present embodiment is the least likely to cause a step, a settlement, or the like, which hinders the traffic of the vehicle, after constructing the block pavement.

[Experiment to confirm the effect of geogrid]
The present inventors conducted the following experiments on the pavement structure according to the present embodiment, the pavement structure not reinforced, and the pavement structure using the reinforcing plate.

(1) First Outdoor Experiment For each pavement structure, the load and the amount of deflection at the loading position (hereinafter, referred to as “direct deflection”) were measured. The smaller the amount of deflection directly below, the higher the supporting capacity of the pavement structure. The test conditions are as follows.

Measurement date: Approximately 10 days from 2015/8/22 Set load: 8065.8N
Setting K ₃₀ value: 100 MN / m ³
Number of times of loading: 1 measurement for each point 16 times FIG. 7 is a graph showing the measurement results of the amount of deflection immediately below. As shown in FIG. 7, the pavement structure using the reinforced plate was the smallest in the first time (immediately after the construction), but the pavement structure using the geogrid according to the present embodiment was the second and subsequent times. The smallest value is shown. In addition, after the second time, except for the pavement structure that has not been subjected to the reinforcement method, the values show generally stable values, and the pavement structure using the geogrid according to the present embodiment has the most stable and high bearing capacity. I understand.

(2) Second outdoor experiment The deflection ratio was measured for each pavement structure. The larger the value of the deflection ratio, the higher the load transmission rate to the periphery. The test conditions are as follows.

Measurement date: Approximately 10 days from 2015/8/22 Set load: 8065.8N
Setting K ₃₀ value: 100 MN / m ³
FIG. 8 is a graph showing the measurement results of the deflection ratio. As shown in FIG. 8, the deflection ratio of the pavement structure using the geogrid according to the present embodiment shows the most stable and large value, and the deflection ratio is most excellent in most cases. The pavement structure using the reinforcing plate showed the smallest value throughout. This indicates that the pavement structure using the geogrid according to the present embodiment has a stable and high load transfer rate.

(3) Indoor experiment Next, an indoor experiment was performed using a simplified cross-section reproduction model. When the same load is applied, the smaller the amount of deflection, the higher the supporting force. Therefore, by measuring the amount of deflection, it is possible to evaluate the supporting force reinforcing performance and the load transmission range. Therefore, a load was applied to the simplified section reproduction model, and the difference in performance due to the construction method at the time of loading was measured. In the simplified cross-section reproduction model, sponge rubber was used instead of sand in order to clarify the change at the time of loading rather than sand.

  FIG. 9 is a graph showing a change in the amount of deflection with respect to the applied load. As shown in FIG. 9, it can be seen that as the load increases from around 500 N, the amount of deflection when the geogrid is used is minimized. That is, when the geogrid is used, it can be said that the supporting force reinforcing performance is higher than other construction methods.

  FIG. 10 is a diagram illustrating a load transmission range when the reinforcing method is not performed, FIG. 11 is a diagram illustrating a load transmission range when the reinforcing plate 13 is used, and FIG. It is a figure which shows the load transmission range at the time of using. In all of FIGS. 10 to 12, the applied load is 1250N. At the time of loading, the larger the deformation range of the sponge rubber 15, the more the load is transmitted. In FIG. 10, the load transmission range is L1, and the sinking amount from the original upper surface position of the interlocking block 11 indicated by the dotted line is d1. In FIG. 11, the load transmission range is L2, and the sinking amount from the original upper surface position of the interlocking block 11 indicated by the dotted line is d2. In FIG. 12, the load transmission range is L3, and the sinking amount from the upper surface position of the original interlocking block 11 shown by the dotted line is d3. As is clear from FIGS. 10 to 12, the load transmission range is L3> L2> L1, and the largest case is when the geogrid 9 is used, and the next case is when the reinforcing plate 13 is used. If not, it is minimal. The settlement amount of the interlocking block 11 is d3 <d2 <d1, and is the smallest when the geogrid 9 is used, and the largest when the reinforcing plate 13 is used and when the reinforcing method is not performed. It has become.

  From the above, it was found that the reinforcement method using the geogrid exerts a sufficient effect on the workability, the pavement support force, and the load dispersion effect. This makes it possible to shorten the construction time and extend the service life of the pavement.

[About construction]
(1) The effect of the geogrid is most exerted when it is installed on a sand layer. However, a suitable effect can be obtained even when used between the sand and the roadbed.

  (2) Around a pavement edge or a road surface facility such as a manhole where a step easily occurs, a geogrid may be laid in a double shape, that is, in a sandwich shape at positions above and below sand.

  (3) As the pavement block is laid, the geogrid gradually sags. If the sag increases, a part of the geogrid may be cut to provide an opening.

  (4) Do not lay the geogrid on top of each other.

  (5) In the curved part, the geogrid is cut and accommodated.

  (6) The joints of the pavement block and the joints of the geogrid joints generated by cutting or laying must not match. FIG. 13 is a diagram illustrating a state where the geogrid is cut along the width of the road and the width is adjusted. The portion indicated by the arrow corresponds to the joint. FIG. 14 is a diagram illustrating a state in which joints are formed between the paving blocks 11. The portion indicated by the arrow corresponds to the joint of the geogrid. As shown in FIG. 14, the joint of the geogrid and the joint of the pavement block are not matched. This makes it possible to maximize the effect of the geogrid.

  (7) According to the present embodiment, compared to other reinforcing methods or no reinforcement, the joint line, which is likely to be generated at the time of joint adjustment, can be prevented from meandering due to the biting between the blocks, so that the joint adjustment is facilitated and the joint is easily adjusted. It becomes easier to pass through the line.

  As described above, according to the present embodiment, the flexure of the pavement surface is reduced, and the stress generated in the sand layer 7 and the roadbed layer 5 is reduced. As a result, the step and settlement by the pavement block 11 are suppressed. Can be achieved.

DESCRIPTION OF SYMBOLS 1 Pavement structure 3 Subgrade 5 Subgrade layer 7 Sand layer 9 Geogrid 9a Vertical strand 9b Horizontal strand 9c Node 11 Pavement block (interlocking block)
13 Strengthening plate

Claims (6)

A pavement method using a pavement block,
Forming a subbase layer on the subgrade,
Forming a sand layer on the roadbed layer;
A vertical and horizontal strand having a length determined from the maximum particle size of the spreading sand of the spreading sand layer, and a two-way stretch type geogrid composed of nodes of the vertical strand and the horizontal strand, on the spreading sand layer. Laying process,
Laying a paving block on the geogrid,
A pavement method comprising laying the pavement block such that a joint between one geogrid and another geogrid is always located immediately below the pavement block. A pavement method using a pavement block,
Forming a subbase layer on the subgrade,
Laying a first geogrid on the roadbed layer;
Forming a sand layer on the roadbed layer on which the first geogrid is laid;
Laying a second geogrid on the sand layer,
Laying a paving block on the second geogrid,
The first and second geogrids are bidirectionally stretched composed of vertical strands and horizontal strands having a length determined from the maximum particle size of the bed sand of the bed sand layer, and nodes of the vertical strands and the horizontal strands. Ri type of geogrid der,
Wherein the first and second geo-grid paving wherein the Rukoto laid in a predetermined range including the surrounding pavement edge or road facilities.   The pavement method according to claim 1, wherein the nodes of the geogrid have a greater thickness than the vertical strands and the horizontal strands, and have a convex shape.   The pavement method according to claim 3, wherein the thickness of the vertical strand and the horizontal strand is 1.0 mm or more and 3.0 mm or less, and the node is 2.0 mm or more and 4.0 mm or less. . A pavement structure using a pavement block,
A subbase layer formed on the subgrade,
A sand layer formed on the roadbed layer,
A two-way stretch type geo laid on the bed sand layer and composed of vertical strands and horizontal strands having a length determined from the maximum particle size of the bed sand of the bed sand layer, and nodes of the vertical strands and the horizontal strands Grid and
And a pavement block laid on the geogrid,
A pavement structure wherein a joint between one geogrid and another geogrid is always located immediately below a pavement block.   On the roadbed layer, another two-way stretching type comprising vertical strands and horizontal strands having a length determined from the maximum particle size of the bed sand of the bed sand layer and nodes of the vertical strands and the horizontal strands The pavement method according to claim 1, further comprising a step of laying a geogrid.