JP5401746B2 - Lawn protection mat and protection structure using it - Google Patents

Description

  The present invention relates to a lawn protection mat and a protection structure using the same.

  Conventionally, there is a roadbed (for example, Patent Document 1) that protects a vegetation surface on which a grass plant such as a lawn is planted to protect a lawn, which is a soft or synthetic resin roadbed, and has a plurality of through holes. .

  And a reusable device for temporarily covering a portion of the playing field, wherein the surface is capable of supporting one or more persons above the portion of the playing field, A plurality of holes for sending air to a plant covered by the device, having a shape that creates a free space between the surface and the playing field, as positioning means for positioning the device in the playing field; Positioning means comprising: a downwardly extending member; and a leg that extends transversely from the downwardly extending member and that can distribute a load applied to the downwardly extending member. There is a cover (for example, Patent Document 2) that allows the plant covered by the apparatus to grow, and this cover is formed from a plastic material, and is used after temporarily covering the playground. Can not be obtained by the existing covering device flooring type, it is possible to obtain adequate protection of the grass portion.

Japanese Utility Model Publication No. 2-1242 Japanese Patent Publication No. 5-504897

  By using the above Patent Documents 1 and 2, lawn and the like can be protected. However, in Patent Document 1, the lower part of the through hole is in contact with the ground, and in Patent Document 2, the leg is in contact with the ground. When sandwiched between vegetation surfaces, the lawn is partially damaged.

  Moreover, in patent document 1, since the front-end | tip of a lawn protrudes from a through-hole, there exists a problem which damages a lawn when stepping on a lawn, such as passing on a roadbed.

  Moreover, although the thing of the said patent documents 1 and 2 is equipped with the hole for ventilation | gas_flowing, when sunlight itself etc. receive and temperature rises, heat | fever will conduct to a leg part and there exists a possibility of having a big bad influence on a lawn. is there.

  Accordingly, an object of the present invention is to provide a lawn protection mat capable of obtaining a state suitable for lawn growth without dispersing the load applied from above and damaging the lawn, and a lawn protection structure using the same. To do.

The invention according to claim 1 is a lawn protection mat laid on a lawn to protect the lawn, wherein the lawn protection mat has a void and has a three-dimensional network structure in which a synthetic resin wire is made into a three-dimensional network. The body has a thickness of 25 to 35 mm, the entangled portions of the wires are fixed at the welded portion by heat welding, and by changing the density in the thickness direction, the lawn side is a sparse part and the anti-grass side is a dense part The sparse part is thicker than the dense part, the thickness of the sparse part is 17 to 33 mm, the thickness of the dense part is 2 to 8 mm, and the porosity of the sparse part is 90 to 98%. The porosity of the part is 79 to 88%, the density is 1200 to 1900 g / m ³ , and the wire is white.

  The invention according to claim 2 uses the lawn protection mat according to claim 1, lays the mat with the sparse portion on the lawn side, and lays a cover on the mat.

  According to a third aspect of the present invention, the cover has a ventilation portion.

  According to a fourth aspect of the present invention, the cover has a rib portion projecting in the intersecting direction on the lower surface of the flat plate portion having a through hole, and a plurality of leg portions, and the lower surface of the leg portion includes the rib portion. It is located below the lower edge.

  According to the configuration of the first aspect, the lawn covered with the mat enters the sparse part, is protected without being crushed, and grows in the void without standing in the steam. In addition, since there is a sparse part under the dense part, the load applied to the dense part on the upper surface is dispersed, the load is not partially concentrated on the sparse part, and the lawn is not partially damaged.

  Moreover, according to the structure of Claim 1, the nurturing | growth part of a lawn can be ensured by taking a thick part, and since there are few dense parts, handling, such as winding in a roll shape, becomes easy.

  Moreover, according to the structure of Claim 1, when the porosity of a sparse part is less than 90%, the nurturing | growth space of a lawn cannot fully be ensured, but leaf tips are in the space | gap part by setting it as 90% or more. Protected while standing. On the other hand, if it exceeds 98%, the strength of the sparse portion decreases, and the effect of dispersing the load from above cannot be obtained sufficiently.

  In addition, if the thickness of the dense portion is less than 2 mm, it is difficult to obtain a predetermined strength, and if it exceeds 8 mm, air permeability is impaired and light does not easily pass. On the other hand, if the porosity of the dense portion is less than 79%, the air permeability is lowered and it becomes difficult to transmit light.

Moreover, since the mat is white, heat absorption of the mat itself can be suppressed, and temperature stress under growth conditions can be reduced. Moreover, since the density of the mat is 1200 to 1900 g / m ³ , the temperature stress under the growth conditions can be lowered by reducing the thermal conductivity of the mat itself and increasing the proportion of the voids.

  Moreover, according to the structure of Claim 2, it protects with a cover, and the load which the cover received is disperse | distributed by a mat | matte, and the partial concentration of the load to a lawn can be prevented.

  Moreover, according to the structure of Claim 2, it protects with a cover, and can disperse | distribute the load which the cover received by the net structure of a mat | matte, and can prevent partial concentration of the load to a lawn.

  Moreover, according to the structure of Claim 3, the air permeability to a lawn can be ensured through a cover and a mat | matte.

  Moreover, according to the structure of Claim 4, by irrigating from the top of a cover, the effect of lowering the temperature of a legged cover itself and the temperature of internal space is acquired, and the water | moisture content to the vegetation surface from a through-hole is acquired. Can be replenished.

It is sectional drawing of the protective structure which shows Example 1 of this invention. It is sectional drawing of a mat | matte and a vegetation surface same as the above. It is a side view of the mat wound to roll shape same as the above. It is a side view explaining a test method same as the above. It is a graph which shows the relationship between the compression distortion of the result of Table 2, and a compression load same as the above. It is a graph which shows the relationship between the compression distortion of the result of Table 3, and a compression load same as the above. It is a graph which shows the relationship between the compression distortion of the result of Table 4, and compression load same as the above. It is sectional drawing of the protective structure which shows Example 2 of this invention. It is a perspective view which shows an example of a cover same as the above. It is a perspective view which shows an example of another cover same as the above. It is sectional drawing which shows an example of another cover same as the above. It is a side view explaining a test method same as the above. FIG. 13A is a plan view and FIG. 13B is a cross-sectional view. It is a graph which shows a temperature measurement result same as the above. It is a flowchart figure which shows Example 3 of this invention.

  Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all of the configurations described below are not necessarily essential requirements of the present invention. In each embodiment, by adopting a new lawn protection mat different from the conventional one, an unprecedented lawn protection mat and a protection structure using the same can be obtained. The lawn protection mat and the protection using the same Describe the structure.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 7 show Embodiment 1 of the present invention. As shown in FIG. 1, a lawn 2 is vegetated on a vegetation surface 1 such as a soccer field or a park, and the lawn 2 is protected by a protective structure.

  The protective structure includes a substantially flat mat 11, which is laid on the vegetation surface 1. The mat 11 is a three-dimensional network structure in which a synthetic resin wire rod 12 is formed into a three-dimensional network, and has a gap portion 13 continuously in the thickness direction and the planar direction, and has a thickness on the lawn side. The lower surface side in the direction is the sparse portion 14, and the upper surface in the thickness direction on the anti-grass side is the dense portion 15.

  The wire 12 is made of a thermoplastic resin as a raw material, and is made of, for example, polypropylene, polyester, or polyethylene, and has a diameter of about 0.1 to 5 mm (0.1 mm or more and 5 mm or less: the same applies hereinafter). In addition, although the wire 12 has a circular cross section, the diameter of the wire 12 is a dimension when the cross section is converted into a circle, for example, in the case of a square cross section other than the circular cross section. And, when used for the protective structure, if the diameter of the wire 12 is less than 0.1 mm, the strength is not sufficient, and the lawn 2 cannot be protected because it tends to be crushed by a load from above, while 5 mm If it exceeds 1, the strength is sufficient, but the flexibility is lowered, and the porosity (ratio of voids per unit volume) is reduced, and the preferred range is 0.1 to 2.0 mm.

  Although the thickness T of the mat 11 is 50 mm or less and depends on the height of the lawn 2, it is preferably 25 to 35 mm. The height of the lawn 2 is not more than the thickness T of the mat 11 and is 15 to 20 mm. Preferably, the lawn 2 is made to have a height equal to or less than the thickness T of the sparse portion 14 before the mat 11 is laid.

  As an example, in a mat 11 having a size of 25 to 35 mm, the thickness T2 of the dense portion 15 is 2 to 8 mm, and the thickness T1 of the sparse portion 14 is 17 to 33 mm. In addition, thickness T2 shall be 1/2 or more of thickness 1. The porosity of the dense portion 15 (ratio of voids per unit volume) is 90 to 98%. Further, the porosity of the dense portion 15 is smaller than the porosity of the sparse portion 14 and is 79 to 88%. And when the porosity of the sparse part 14 is less than 90%, the nurturing space of the lawn 2 cannot be secured sufficiently, and when it exceeds 98%, the strength of the sparse part 14 decreases, and the load from above is reduced. A sufficient dispersion effect cannot be obtained, and 94 to 98% is particularly preferable. In addition, if the thickness of the dense portion 15 is less than 2 mm, it is difficult to obtain a predetermined strength, and if it exceeds 8 mm, air permeability is impaired and light does not easily pass. . On the other hand, when the porosity of the dense portion 15 is less than 79%, the air permeability is lowered and it becomes difficult to transmit light.

The density of the mat 11 is about 1200 to 1900 g / m ³ , and preferably 1400 to 1600 g / m ³ .

  Further, the mat 11 is white, and in this example, a white wire 12 is used.

  In the method of manufacturing the mat 11, an extruder that melts a thermoplastic resin is used. The extruder includes a die (not shown) that extrudes a large number of wires 12 and a plurality of wires 12 extruded from the die. Is formed by being fixed at a welded portion 121 by heat fusion at a portion entangled at random. In order to change the density in the thickness direction, the molten thermoplastic synthetic resin is extruded downward from a number of nozzles and is naturally lowered between a pair of submerged belt conveyors, and is taken slower than the above-described lowering speed. There is a method in which the distance between the pair of belt conveyors is narrower than the extruded molten resin bundle, and one side of the molten resin bundle contacts the belt conveyor before being submerged by the belt conveyor. Since the surface portion of the material falls on the belt conveyor and moves to the inside of the molten thermoplastic synthetic resin bundle, it becomes a dense state. As a matter of course, the dense portion 15 which is a surface portion having a low porosity has a larger number of welded portions 121 than the sparse portion 14 having a high porosity, and the tensile strength is remarkably increased.

  The lawn 2 is protected by laying a mat 11 on the vegetation surface 1 with the sparse portion 14 side down. As shown in FIG. 3, the mat 11 is provided with a roll body 21 wound in a roll shape, and the roll body 21 is unfolded and turned upside down and laid. Further, if necessary, fixing pins 22 are inserted into appropriate portions of the mat 11, and the pins 22 are inserted into the vegetation surface 1 and fixed.

  Thus, the lawn 2 covered with the mat 11 enters the sparse portion 14, is protected without being crushed, and can grow in the void portion 13 without being steamed and standing with leaves.

Further, since the mat 11 is white, heat absorption of the mat 11 itself can be suppressed, and temperature stress in the growth conditions can be reduced. Further, since the density of the mat 11 is 1200 to 1900 g / m ³ , preferably 1400 to 1600 g / m ^3, it is possible to reduce the thermal conductivity of the mat 11 itself and increase the ratio of the voids 13 in the growth conditions. Temperature stress can be reduced.

  In addition, by providing the dense portion 15, a sufficient restoring force against tension and compression can be obtained on the mat 11, laying work and removal work can be easily performed, and a uniform laying state can be obtained. Furthermore, work efficiency in transportation and storage is improved.

  Further, the upper surface of the mat 11 is constituted by the dense portion 15 and is difficult to slip, so that the work can be safely performed on the mat 11. In addition, there is a sparse part 14 with a blister-like structure (after drying) at the lower part of the dense part 15 on the upper surface, and the point pressure applied to the upper surface is dispersed so that the point pressure is partially concentrated on the sparse part 14 Can be prevented and the lawn 2 of the sparse part 14 can be protected.

  In addition, since the net-like wire 12 that forms the dense portion 15 and the sparse portion 14 has an elastic restoring force, even if the pin 22 is inserted into the mat 11, the inserted portion does not spread and the mat 11 can be fixed without rattling. On the other hand, the operation of removing the pin 22 is also facilitated. Further, since the portion into which the pin 22 is inserted does not remain wide, it is suitable for repeated use.

  Thus, in this embodiment, in the lawn protection mat 11 that is laid on the lawn 2 and protects the lawn 2, it is a three-dimensional network structure composed of the synthetic resin wire 12 having the gap portion 13, In the thickness direction, the wire 12 has a sparse part 14 on the lawn side and a dense part 15 on the opposite lawn side. Therefore, the lawn 2 covered with the mat 11 enters the sparse part 14 and is protected without being crushed. It grows in a standing state without being steamed. In addition, since the sparse portion 14 is located under the dense portion 15, the load applied to the dense portion 15 on the upper surface is dispersed, and the load is not partially concentrated on the sparse portion 14, and the lawn 2 is partially damaged. There is no.

  Further, in this embodiment, since the sparse portion 14 is thicker than the dense portion 15, the thickening of the sparse portion 14 can secure the nurturing space for the lawn 2 and the dense portion 15 is small. It becomes easy to handle in a roll shape.

  Further, in this example, since the porosity of the sparse portion 14 is 90% or more in this example, if the porosity of the sparse portion 14 is less than 90%, the nurturing space of the lawn 2 cannot be sufficiently secured, By setting it to 90% or more, the leaf portion is protected in the gap 13.

  Further, as an effect on the embodiment, the dense portion 15 has a strength and thickness because the curled wire 12 is overlapped in the vertical direction and a large number of the wires 12 and 12 are welded together at the weld portion 121. The air permeability of the direction can be ensured and light can be transmitted.

Next, a compression test of the mat 11 will be described. As the mat 11, a mat having a total thickness of 30 mm, the dense portion 15 having a thickness of 4 mm, and the sparse portion 14 having a thickness of 26 mm was used. The test product A is a mat 11 having a density of 1200 g / m ³ , the test product B is a mat 11 having a density of 1500 g / m ³ , and the test product C is a mat 11 having a density of 1900 g / m ³ .

  Here, as a representative example, data of the test product B is shown in Table 1 below.

  A compression test of the test products A, B, and C was performed. As shown in FIG. 4, a test article having a flat surface of 250 mm × 250 mm is placed on a flat placement surface 31 with the sparse portion 14 facing down, and a loading board 32 having a diameter of 100 mm is placed in the center of the upper surface of the test article. Then, the lifting / lowering rod 33 was lowered and a load was applied to the test article stepwise by the loading board 32, and the compression rate at that time was determined. Three test pieces were prepared and subjected to compression tests.

The applied load: The load per unit area is 85.7 N: 1.2 kN / m ³ , 107.1 N: 1.5 kN / m ³ , 142.9 N: 2.0 kN / m ³ , 178.6 N: 2.5 kN / m ³ .

  The test results of the test product A are shown in Table 2 below, and a graph corresponding to Table 2 is shown in FIG.

  The test results of the test product B are shown in Table 3 below, and a graph corresponding to Table 3 is shown in FIG.

  The test results of the test product C are shown in Table 2 below, and the graph corresponding to Table 4 is shown in FIG.

  From the result of the above compression test, it was found that the test products A, B, and C have sufficient strength, for example, when holding a concert in a soccer field.

  FIGS. 8-14 shows Example 2 of this invention, attaches | subjects the same code | symbol to the same part as the said Example 1, and abbreviate | omits the detailed description, The protection structure of this example is the said structure. A protective cover is provided on the mat 11. As this protective cover, as shown in FIG. 9, a plate-like cover 43 having a plurality of through holes 42 formed in a flat plate portion 41 made of wood or synthetic resin, or as shown in FIGS. An example is a legged cover 47 in which ribs 45 and 45A are projected in the crossing direction on the lower surface of a synthetic resin flat plate portion 44 having light 42, and a plurality of leg portions 46 are provided on the lower surface. Flat plate portions 41 and 44. The lower surface of the leg portion 46 is positioned below the lower edge of the rib portions 45, 45A, and a space is provided below the flat plate portion 44 between the lower surface of the flat plate portion 44 and the lower surface of the leg portion 46. Since 48 is formed, it is also possible to lay the cover 47 with legs directly on the vegetation surface 1, and the lawn 2 in the space 48 is well protected. However, although the ratio is small with respect to the total area, the lawn 2 is crushed by the legs 46, and when used alone, it is inevitable that the lawn 2 corresponding to the legs 46 will be damaged.

  In the present embodiment, the cover 47 with legs is overlapped on the mat 11 to form a protective structure. And the test was done about this protective structure.

  As shown in FIG. 12, in the preliminary test, a protective material 51 such as a palm mat, cocoons, a net (resin mesh net), a turf protection mat, and a cocoon is laid on the lawn 2 and the legs are attached thereto. A cover 47 is placed, a weight 52 such as H-shaped steel is placed on the legged cover 47, covered with a polyethylene sheet 53 provided with a vent (not shown), and temperature is measured for 48 hours. The state of the turf was observed after and 96 hours later. “None” is an example in which the legged cover 47 is directly laid on the lawn 2. The preliminary test was conducted in Niigata City in late May.

  The results are shown in Table 5 below.

  The temperature measurement showed a tendency to keep the temperature of the lawn low when using a net with a net, a turf protection mat, and this.

  Since it seemed that the net and the grass protection mat were effective from the state of the lawn after 96 hours, these tests were continued and the results after 144 hours were observed, and the results shown in Table 6 below were obtained.

  From the results of the preliminary test, it was confirmed that the net was effective when it was a mesh net, so the test was performed using an equivalent of the mat 11. This equivalent was black. The following tests were conducted in Niigata City in early June. As a result after 48 hours, it was considered that the surface and the internal temperature of the lawn 2 were lower when the net was used as the protective material 51 and the lawn 2 was more effective.

  However, the equivalent of the mat 11 has the grass 2 with the tip of the lawn 2 standing up, whereas the shigara net has a part where the lawn 2 falls down. In addition, a test was conducted using a net having various sizes. The results are shown in Table 7 below.

  Note that, for example, “7 * 7 * 3.4” is a standard of the net, as shown in FIG. 13, where one side a = 7 mm, the other side b = 7 mm, and the thickness t = 3.4 mm at the opening of the mesh. Gara Net 61. Note that the net 61 is continuous in the planar direction in FIG. 13A, is continuous in the left-right direction in FIG. 13B, has a predetermined width, and has a roll shape in the length direction, similar to the mat 11. Can be wound. As shown in the drawing, the grass net 61, which is a lawn protection mat, is a net-like structure made of synthetic resin wire materials 62, 63, and includes a plurality of wire materials 62 in one side direction and a plurality of wires in a crossing direction. The wire 63 in the other side direction is crossed by the crossing portion 64, and a mesh 65 serving as a gap is formed between the wires 63 and 64. The mesh 65 has a square shape with one side a × the other side b. Further, the wire rods 63 and 64 have a strip shape wider in the width direction than the thickness direction, the thickness t of the intersecting portion 64 is formed to be thicker than the other portions, and the outer surface of the intersecting portion 64 is a convex curved surface. It is configured. Note that the mesh 65 of the net 61 may be hexagonal, and the shape is not limited. Further, in the above test, the black or green tail net 61 is used. However, it is preferable that the net 61 is also white or white as in the case of the mat 11.

  Moreover, the result of having measured the surface temperature of the lawn 2 from 8:00 to 16:00 is shown in FIG.

From the above results, it was found that the mat 11 is the best for the lawn. In addition, like the shield net 61 used as the protective material 51, the tail net 61 can provide the necessary effects and is suitable for turf protection. In particular, in this example, the area of the mesh 64 was 100 mm ² or less, and particularly good results were obtained.

  Furthermore, in a test using three types of mats 11 having different densities, the results shown in Table 8 below were obtained. This test was conducted in Niigata City in the middle of June. The test time and the test place are only examples, and the season and place where the protection structure is used may be anywhere.

From the above test, compared with the other protective materials 51, the leaf tip of the lawn 2 stands up with any mat 11 and the best result is obtained compared with the other. Further, among the mats 11, the density is 1500 g / m ³ . The thing of the leg 46 did not stick to the lawn 2, and the result was the least yellowing.

  Further, in this embodiment, the lawn protection mat according to claim 1 is used, the mat 11 is laid with the sparse portion 14 on the lawn side, and the legged cover 47 as a cover is laid on the mat 11. Therefore, it can be protected by the cover 47 and the load received by the cover 47 can be dispersed by the mat 11 to prevent partial concentration of the load on the lawn 2.

  In this way, in this embodiment, the net 61 for the lawn protection mat of the mesh structure composed of the wire 62, 63 made of synthetic resin and having the mesh 65 as the gap is laid on the lawn 2, Since the leg cover 47 as a cover is laid on the net 61, the cover 47 protects the load and the load received by the cover 47 is dispersed by the mat 11 to partially concentrate the load on the lawn 2. Can be prevented. However, since the net 61 has a simpler structure than the mat 11, the net 61 is inexpensive and cost-effective.

  Further, in this embodiment, since the flat plate portion 44 that is a plate-like material of the cover 47 has a ventilation portion, the air permeability to the lawn 2 can be ensured through the cover 47 and the mat 11.

  Further, as an effect on the embodiment, the shin net 61 has a thicker crossing portion 64 than the other portions, and the outer surface of the crossing portion 64 is a convex curved surface. Partially applying a load can be suppressed. In addition, various types of covers can be used for the laying on the net 61, but in particular, a cover having a space 48 is preferable, and the cover 47 having the space 48 is used and the height of the lawn 2 is measured. When the net 61 is used while the thickness is smaller, the lawn 2 inserted through the mesh 65 is kept standing in the space 48 and can be bred well. In order to form the space 48, a member that forms the space 48 under the flat plate portion 44 that is the upper surface and is grounded on the net 61, such as the leg portion 46 and the rib portions 45 and 45A, is provided. That's fine.

  FIG. 15 shows a third embodiment of the present invention. The same reference numerals are given to the same portions as those of the above-mentioned embodiments, and detailed description thereof is omitted. In this example, the lawn before the mat 11 is laid is shown. This relates to the second processing. The above-described mat 11 having a thickness of 30 mm will be described as an example.

  First, about 2 to 3 weeks before using the protective structure, the height of the lawn 2 is cut to about 23 to 30 mm to be equal to or less than the thickness of the mat 11 (first cutting). In addition, soil improvement material is sprayed on the lawn 2. Then, 1-2 weeks before, the height of the lawn 2 is cut to about 21-28 mm (intermediate cutting). Note that there is at least one day interval between the first trimming and the middle trimming. Just before use (within 24 hours), the lawn 2 is cut to a height of about 15 to 20 mm (cutting just before). The height of the lawn 2 is made lower than the thickness of the sparse portion 14 by cutting immediately before this. The mat 11 is sufficiently irrigated before the mat 11 is laid, and then the mat 11 is laid on the lawn 2 and a legged cover 47 is laid on the mat 11 as necessary.

  In addition, after laying the legged cover 47, irrigation from above the legged cover 47 provides an effect of lowering the temperature of the legged cover 47 itself and the temperature of the internal space 48, and from the through hole 42. It is possible to supply water to the vegetation surface 1.

  As described above, in this embodiment, the lawn 2 is trimmed a plurality of times before use, the height of the lawn 2 is gradually lowered, and then the lawn 2 is mowed again immediately before use to stress the lawn 2. The condition after the protective structure is removed is also improved, and the condition suitable for the lawn 2 can be made before the mat 11 and the net 61 are laid.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the gist of the present invention. For example, in the examples, the three-dimensional network structure is referred to as a flat shape, but the present invention is not limited to this, and various shapes such as a structure in which wires are randomly entangled can be used. Further, the density of the sparse part and the dense part can be appropriately selected depending on the use conditions. Moreover, although the cover with a leg was shown in the Example, the concentration of the load by a rib part can be prevented also with the cover provided with the rib part without a leg part. In addition, the shape of the net can be selected as appropriate.

1 Vegetation surface 2 Lawn
11 mat
12 Wire
13 Gap
14 Sparse part
15 Dense part
42 Through-hole
43 Plate cover (protective cover)
44 Flat part
45, 45A rib part
46 Leg
47 Cover with legs (protective cover)
61 Shigara Net (Matte)
62, 63 wire

Claims (4)

In the lawn protection mat that is laid on the lawn to protect the lawn, the lawn protection mat is a three-dimensional network structure having a void and a three-dimensional mesh of synthetic resin wire, 25 to 35 mm, the entangled portions of the wires are fixed at the welded portion by heat welding, and by changing the density in the thickness direction, the grass side is a sparse part and the anti-grass side is a dense part, and the sparse part is more The portion is thick, the thickness of the sparse portion is 17 to 33 mm, the thickness of the dense portion is 2 to 8 mm, the porosity of the sparse portion is 90 to 98%, and the porosity of the dense portion is 79 to A lawn protection mat comprising 88%, a density of 1200 to 1900 g / m ³ , and the wire is white. A lawn protection structure using the lawn protection mat according to claim 1, wherein the mat is laid with the sparse portion on the lawn side, and a cover is laid on the mat. The lawn protection structure according to claim 2, wherein the cover has a ventilation portion. The cover has a rib portion projecting in a crossing direction on a lower surface of a flat plate portion having a through hole and a plurality of leg portions, and the lower surface of the leg portions is positioned below a lower edge of the rib portion. The lawn protection structure according to claim 3.

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