JP3091154B2 - Ground structure such as ground and method of forming it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground structure such as a ground excellent in drainage property and soil stability and a method for forming the same.

[0002]

2. Description of the Related Art Soil-based pavement ground, such as outdoor sports facilities and park facilities, such as a ground, is required to be continuously used by draining immediately after rainfall. Therefore, measures have been taken to promote and improve drainage. Have been.

[0003] As this means, as the surface aggregate of the ground, a mixture of a conventional surface aggregate and fine aggregate for promoting drainage such as sand or volcanic gravel having a higher permeability than the conventional aggregate is employed. ing. Precipitation on the surface layer formed in this manner is drained by penetrating the surface layer and naturally penetrating into the subgrade such as the lower Kanto loam layer.

[0004]

As described above, in the case where rainwater permeates directly from the surface layer onto the subgrade, the drainage capacity of the subgrade is low, and when the rainfall is large, There are problems that cannot be addressed. In addition, when fine aggregate is mixed on the surface layer, it is difficult to mix the mixed components uniformly, so that there is a problem that uneven mixing cannot be avoided and good ground cannot be obtained. That is, if the mixing ratio of the fine aggregate for promoting drainage is small, a sufficient drainage effect cannot be obtained. On the other hand, if the mixing ratio of the fine aggregate for promoting drainage is too large, the drainage is improved instead of improving the drainage property. The soil is not stable because it becomes dry and powdery. As a result, the comfort of sports and walking is lost. Therefore, there is a demand that a drainage ground that can be used as a natural and comfortable ground in park facilities and outdoor sports facilities, and that has excellent drainage properties can be realized at low cost.

An object of the present invention is to provide an inexpensive ground structure such as a ground which is excellent in drainage performance and excellent in usability.

[0006]

In order to achieve the above object, the present invention employs the following means. First, a sub-base layer formed by laying a sub-base layer aggregate such as volcanic gravel to a predetermined thickness on a leveled sub-bed is formed, and a middle-layer aggregate such as loam soil is formed to a predetermined thickness on the sub-base layer. The thing laid in the middle is made into a middle layer which is unevenly shaped, and a drainage core having a vertical hole filled with a water-repellent aggregate is arranged at a predetermined pitch in this middle layer. Furthermore, a ground layer with excellent drainage properties is obtained by laying a mixture of middle-layer aggregate and water-repellent aggregate on the middle layer with a drainage core and laying it to a predetermined thickness to make it uneven. To obtain the ground structure.

[0007] In the above-mentioned ground structure, specifically, the roadbed layer is made of irregularly shaped volcanic gravel to a thickness of 100 mm to 250 mm, and the middle layer is formed by unevenly adjusting intermediate aggregate such as loam soil. It has excellent drainage properties by being formed to a thickness of 50 mm to 150 mm.

The drainage core 4a has a diameter of 8 mm to 25 m in the middle layer.
The vertical holes 3a arranged at a pitch of 100 mm to 200 mm are filled with a water-repellent aggregate, so that clogging due to adhesion of mud or the like during penetration of rainwater or the like can be prevented, and the drainage capacity does not always decrease. It is like that.

Secondly, the above-mentioned ground structure such as a ground is provided with an underdrain pipe on a subgrade as required to improve drainage, and a drainage outlet for regulating the amount of drainage is provided at a drain port of the underdrain pipe. Means are provided. By allowing the humidity due to rainwater or the like accumulated in the roadbed layer to be appropriately maintained by the drainage regulating means, the stability of the soil can be promoted.

[0010] Third, for a ground structure that requires a reduction in the construction cost, it is possible to cope with a low-cost ground structure by omitting the formation of a roadbed layer and providing a middle layer and a drainage core directly on the roadbed. is there.

Fourthly, the present invention provides a method for forming a ground structure, comprising providing the above-mentioned roadbed layer on a leveled roadbed, forming an intermediate layer on the roadbed layer, and forming a vertical hole having a predetermined diameter in the intermediate layer. It is arranged at the pitch of. Next, a water-repellent aggregate is laid on the middle layer provided with these vertical holes to fill each vertical hole with the water-repellent aggregate, thereby providing a drainage core. Further, loam soil is laid on the water-repellent aggregate laid on the middle layer, and both the loam soil and the water-repellent aggregate are mixed to obtain a mixing ratio that enables good soil stability to be obtained. It is characterized by the fact that it is made uneven and the surface layer is formed after that, and the construction is easy.

[0012]

Next, an example of an embodiment of the present invention will be described. 5 and 6 show a cross-sectional structure of a ground structure as an example of the embodiment. As shown, a subbase layer 2 is formed on a subgrade 1 and a middle layer 3 is formed on the subbase layer. Vertical holes 3a are provided in the middle layer 3, and a drainage core 4a formed by filling each vertical hole with a water-repellent aggregate is formed. Further, a surface layer 5 is formed on the upper surface of the middle layer provided with the drainage core 4a.

The subgrade 1 is made of ground whose ground such as the Kanto loam layer is not so good in drainage. Volcanic gravel is adopted as the roadbed layer aggregate constituting the roadbed layer 2. Volcanic gravel is made by crushing volcanic rock, is formed in layers by compaction, and is adopted as a material that exhibits excellent drainage even when compressed.

The roadbed layer 2 is formed by depositing the above-mentioned
After being laid to a thickness of 250 mm, various roller machines, such as tire rollers, are rolled by running on the roller machine to form a thickness of 100 to 150 mm. The roadbed layer can be formed of crushed stone, sand, coal shell, slag, etc., in addition to volcanic gravel.

On the upper surface of the roadbed layer 2, a middle layer 3 having a thickness of 50 to 50
It is formed to 150 mm. The middle layer 3 is laid with fine-grained loam soil, and its upper surface is rolled by a roller machine such as a tire roller. In addition, the middle layer 3 may be formed of a nearby Kanto loam, Arakida, black soil, masago, or the like.

The middle layer 3 has a pitch of 100 to 200 mm.
8 to 25m in diameter in a matrix or staggered pattern at intervals of
m vertical holes 3a are provided, and each of the vertical holes 3a is filled with a water-repellent aggregate such as silica powder. The columnar body made of the water-repellent skeleton filled in this way is nothing but a drainage core (sand drain) 4a that connects the surface of the ground and the roadbed layer 2. In addition, a drainage aggregate such as sand may be employed instead of the water-repellent aggregate as a constituent material of the drainage core 4a.

The upper surface of the middle layer 3 and the upper end of the drainage core 4a are further provided with a surface layer 5 having a thickness of 30 to 50 m on which a mixture of a water-repellent aggregate and a loam soil constituting the drainage core is laid.
m. As for the loam soil for the surface layer, alternatives can be adopted as in the case of the middle-layer aggregate.

On the surface layer 5, bittern is further sprayed to promote drying after rainfall.

It is preferable that underdrain pipes 6 are arranged on the surface of the subgrade 1 at appropriate intervals, for example, at a pitch of 1 m (see FIG. 6). An earth pipe, a fume pipe, or the like is used as the culvert pipe 6, and the outlet of the culvert pipe is provided to be able to drain to a drainage facility such as a U-shaped groove. A cap (not shown) can be attached to and detached from the outlet of the underdrain pipe 6, and the drainage can be adjusted so that a certain amount of rainwater stays in the roadbed layer 2. In addition,
The underdrain pipe 6 determines whether or not to be installed according to the condition of the subgrade, the condition of the ground installation, the installation cost, and the like, and may be installed as needed.

Next, a method of forming a ground structure according to the present invention will be described by taking as an example a case where no underdrain pipe is provided (see FIG. 5). As shown in FIG. 1, a subgrade layer 2 is formed by laying volcanic gravel to a thickness of 100 to 250 mm on the top surface of a ground subgrade 1 and rolling it with a roller machine such as a tire roller.

Next, as shown in FIG. 2, loam soil is laid on the upper surface of the roadbed layer 2 to a thickness of 50 to 150 mm, and the intermediate layer 3 is formed by rolling with a roller machine.

Next, as shown in FIG. 3, using a so-called sanding machine, a vertical hole 3a is formed by digging down to a constant pitch and a depth reaching the surface of the roadbed layer 2. Vertical hole 3
“a” is a round hole having a diameter of 8 to 25 mm, and the soil column extracted to provide the round hole is removed later by a cleaning operation.

Next, as shown in FIG. 4, a water-repellent aggregate 4 such as silica is laid so as to cover the surface of the middle layer 3 having the vertical holes 3a. At this time, the water-repellent aggregate 4 is filled in the vertical hole 3a to form the drainage core 4a. In addition, it is also possible to reduce the cost by employing a material filled with inexpensive drainage aggregate such as sand instead of the water-repellent aggregate as the drainage core.

Next, loam soil is added to the surface on which the water-repellent aggregate 4 is laid, and both the loam soil and the water-repellent aggregate are mixed.
The surface layer 5 is formed by carrying out irregularity correction and rolling by a roller machine such as a tire roller (see FIG. 5). Finally, bitterness is sprinkled on the surface layer 5 that has been leveled to improve drainage, and a ground structure capable of coping with drainage during rainfall or the like is completed.

In the case where a culvert pipe is provided (see FIG. 6), a step of excavating a trench 1a for setting a culvert and piping the culvert pipe 6 before laying a volcanic rock or the like to be a subbase layer 2 is performed. Need to be added.

Next, another example will be described. As shown in FIG. 7, the middle layer 3 is provided directly on the subgrade 1, and the drainage core 4 is formed by filling a vertical hole 3a with a water-repellent aggregate.
a is provided. Subgrade 1 via drainage core 4a
Rainwater or the like that has reached the top is dropped from the subgrade or drained from a culvert or the like. Since the formation of the roadbed layer 2 is omitted, the cost of the construction and the like required for the formation of the roadbed layer becomes unnecessary, so that it is suitable for application as a simple drainage facility such as an outdoor facility that is used less frequently. .

[0027]

The present invention has the following effects. First,
Since a structure is adopted in which water permeation from the surface layer due to rainfall or the like flows into the roadbed layer through the drainage core, drainage after rainfall becomes extremely good. In addition, the drainage core is made of water-repellent aggregate with excellent water permeability, and the surface layer is made of a mixture of this water-repellent aggregate and loam soil, which improves drainage and soil stability. . Therefore, it is possible to provide comfortable walking and sports competitions. In addition, since it has excellent drainage properties, there is an effect that it can be used for sports or the like immediately after rain.

Secondly, if a culvert is provided on the subgrade and a regulating means such as a cap for regulating the amount of drainage is provided at the outlet of the culvert pipe, a desired amount of water can be retained in the subbase layer, so that the surface is over-dried. Can be prevented. Thereby, there is an effect that the state of the surface layer enabling comfortable use can be maintained (the soil is stabilized).

Third, since a certain effect can be obtained even if the formation of the roadbed layer is omitted, it is also possible to reduce the construction cost in the ground structure with excellent drainage by simplifying the construction. .

Fourth, in the construction method of the present invention, the water-repellent aggregate laid for arranging the drainage core is used as the surface bone as it is, and the loam soil is laid thereon to mix the two. The construction is extremely easy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first step.

FIG. 2 is a sectional view showing a second step.

FIG. 3 is a sectional view showing a third step.

FIG. 4 is a sectional view showing a fourth step.

FIG. 5 is a sectional view showing a fifth step.

FIG. 6 is a sectional view showing an example of a ground structure provided with an underdrain pipe.

FIG. 7 is a sectional view showing a ground structure in another example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Subgrade 2 Subbase layer 3 Middle layer 3a Vertical hole 4 Water-repellent aggregate 4a Drain core 5 Surface layer 6 Underdrain pipe

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E01C 7/02 E01C 13/00 E01C 7/32

Claims (5)

(57) [Claims] 1. A roadbed layer in which a roadbed aggregate such as volcanic gravel is laid to a predetermined thickness on a leveled roadbed, and a middle layer aggregate such as loam soil having a predetermined thickness on the roadbed layer. A middle layer formed by unevenly laying the thing laid in the middle layer; a drainage core formed by filling a vertical hole provided in the middle layer at a predetermined pitch with a water-repellent aggregate; A ground structure, such as a ground, comprising a surface layer obtained by laying a mixture of a material and the above-mentioned water-repellent aggregate to a predetermined thickness and adjusting the surface unevenness. 2. The roadbed layer according to claim 1, wherein the roadbed layer is formed by irregularly adjusting the thickness of the roadbed layer aggregate to a thickness of 100 mm to 250 mm, and the middle layer is formed by irregularly adjusting the intermediate layer aggregate. The drainage core is formed in a thickness of 50 mm to 150 mm, and the drainage core has a diameter of 8 mm to 25 mm in the middle layer.
Characterized in that the vertical holes are arranged at a pitch of 100 mm to 200 mm. 3. The ground according to claim 1, wherein an underdrain pipe is provided on the subgrade, and a drainage outlet of the underdrain is provided with drainage control means for controlling a drainage amount. Ground structure. 4. A ground structure such as a ground according to claim 1, wherein said middle layer is formed directly on said subgrade. 5. A subbase layer formed by laying a subbase aggregate such as volcanic gravel to a predetermined thickness on a leveled subgrade, and a middle substratum such as loam soil is provided on the subbase layer by a predetermined thickness. After laying on the surface, irregularities are adjusted to form a middle layer, vertical holes of a predetermined diameter are arranged at a predetermined pitch in the middle layer, and a water-repellent aggregate is laid on the middle layer. The vertical hole is filled with the water-repellent aggregate to form a drainage core, the middle-layer aggregate is laid on the water-repellent aggregate laid on the middle layer, and after mixing the two, the unevenness is corrected. A method for forming a ground structure such as a ground, comprising providing a surface layer comprising: