Soil improvement method and soil improvement structure

Abstract

To provide a construction method for improving the ground of a ground, an open space, a park or the like in particular into the ground resistant to heavy rain, and a ground improvement structure formed by the ground improvement construction method.SOLUTION: A soil improvement structure 1 includes a plurality of columnar bodies 10 which are formed of a soil improvement material 11 charged into a plurality of vertical holes P reaching a sandy layer 20 excavated in soil G, respectively, have an aggregate structure having a lattice-shaped or net-shaped continuous void, and have water permeability, in which the columnar bodies 10 are obtained by solidifying the soil improvement material 11 containing one or more of crushed stone, Masago soil, and soil material, a solidifying material, an aggregating agent, and water. Particularly, the ground improvement structure 1 is preferably a structure further including a roadbed improvement material 30 laid on the ground G and the columnar body 10, and a soil improvement material 40 laid on the roadbed improvement material 30.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a ground improvement method for improving the ground of a ground, plaza, park, or parking lot to make it resistant to heavy rain, and to a ground improvement structure formed by this ground improvement method. [Background technology]

[0002] Heavy rainfall from torrential rains and typhoons has long caused flooding and serious damage. When heavy rain falls, existing drainage facilities are unable to handle the water, which can lead to flooding of grounds and other areas, or puddles that can lead to the breeding of pests. In order to respond to such disasters, various ground improvement technologies have been proposed and implemented. Conventional technology related to the present invention includes, for example, the "Ground Improvement Method and Ground Improvement Structure" described in Patent Document 1.

[0003] The ground improvement method described in Patent Document 1 includes a step of excavating multiple vertical holes in the ground, a step of providing multiple catchment basins around the periphery of the ground, a step of forming grooves in the ground that connect the upper openings of adjacent vertical holes and slope downwards toward the catchment basins, a step of providing drainage grooves that connect the upper openings of vertical holes located closest to the catchment basins and slope downwards toward the catchment basins, a step of pouring soil improvement material into the vertical holes, and a step of applying pressure to the soil improvement material poured into the vertical holes. This method includes the steps of forming a pile-shaped body having permeability and water retention, with an aggregate structure having continuous voids in the compacted ground, pouring a ground improvement material into the grooves and drainage ditches, and compacting the ground improvement material poured into the grooves and drainage ditches by applying pressure to form a permeable structure having permeability and water retention, with an aggregate structure having continuous voids in a grid or net shape that slopes downward toward the catch basin and is integrated with the head of the pile-shaped body. The ground improvement material used in this method includes one or more of crushed stone, granular sand, and earth material, a cement-based solidification material, an aggregate agent, and water.

[0004] In the ground improved by this soil improvement method, the bottom end and outer periphery of the pile-like body and the underside of the lattice- or mesh-like permeable structure are in close contact with the ground. This means that in the event of an earthquake, water in the ground can infiltrate not only into the pile-like body from the bottom end and outer periphery, but also from the underside of the lattice- or mesh-like permeable structure (see Figure 1(d)). Furthermore, water that infiltrates into the pile-like body rises within the pile-like body, and when it reaches the top of the pile, it infiltrates into the permeable structure connected to the top. Together with the water that infiltrates into the permeable structure from the underside of the lattice- or mesh-like permeable structure, the water moves laterally through the permeable structure, which slopes downward toward the catchment basin, and is smoothly discharged into the catchment basin. This prevents the ground from becoming unstable or liquefying during an earthquake. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7436970 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the ground improvement method of the invention described in Patent Document 1 can improve the ground on which a structure such as a house is built to make it less susceptible to liquefaction in order to prevent the structure from subsiding or collapsing, but it requires the installation of multiple catch basins, applying pressure to the ground improvement material to compact it, and creating a downward slope toward the catch basins. Therefore, using this ground improvement method in areas larger than the land area of ​​a house, such as sports grounds, plazas, or parks, is costly, and it is difficult to freely develop public facilities such as plazas and parks by installing catch basins or permeable structures.

[0007] Therefore, the present invention aims to provide a construction method for improving the ground, particularly in areas such as grounds, plazas, parks, or parking lots, to make it resistant to heavy rain, and a ground improvement structure formed by this ground improvement construction method. [Means for solving the problem]

[0008] The ground improvement method according to the present invention includes the steps of excavating a plurality of vertical holes in the ground that reach the gravel layer, and pouring a soil improvement material into the vertical holes to form permeable columns in the ground that have an aggregate structure with continuous voids in a lattice or network pattern, the soil improvement material including one or more of crushed stone, granular soil, and soil material, a solidification agent, an aggregate agent, and water. In particular, the ground improvement method preferably further includes the steps of laying a roadbed improvement material on the ground and on the columns, and laying a soil improvement material on the laid roadbed improvement material.

[0009] As a result, rain that falls on ground improved using this ground improvement method seeps into the ground through the multiple pillars that have been formed, reaching the gravel layer.

[0010] The agglomerating agent used in the above step preferably contains a polymer compound consisting of a complex of a magnesium salt of an acrylic acid-dimethylaminoethyl methacrylate copolymer and polyethyleneimine.

[0011] Preferably, the method further includes a step of excavating the plurality of vertical holes so that they fit within a partitioned area, and providing a gutter around the periphery of the area to treat rainwater that overflows from the area.

[0012] On the other hand, the ground improvement structure according to the present invention comprises a plurality of pillars formed by soil improvement material poured into a plurality of vertical holes excavated in the ground, each reaching down to the gravel layer, the pillars having a granular structure with continuous voids forming a lattice or network and being permeable, the pillars being made by solidifying a ground improvement material containing one or more of crushed stone, granular soil, and earth material, a solidification material, an aggregation agent, and water. In particular, it is preferable that the ground improvement structure further comprises a roadbed improvement material laid on the ground and the pillars, and a soil improvement material laid on the roadbed improvement material.

[0013] Furthermore, the granulating agent used in the ground improvement structure preferably contains a polymer compound consisting of a complex of polyethyleneimine and a magnesium salt of an acrylic acid-dimethylaminoethyl methacrylate copolymer.

[0014] It is preferable that the plurality of pillars are arranged so as to fit within a partitioned area, and that a gutter be provided around the periphery of the area to treat rainwater that overflows from the area. [Effects of the Invention]

[0015] Rain that falls on ground improved by the ground improvement method of the present invention permeates into the ground through the formed multiple pillars and reaches the gravel layer, allowing rainwater from the ground surface to permeate into the gravel layer and pass through the gravel layer underground to be sent to the sea. Furthermore, the ground improvement structure of the present invention can achieve the same effects as the ground improvement method of the present invention. In other words, the ground improvement method and ground improvement structure of the present invention relate to rainwater runoff suppression technology that can reduce the amount of rainwater flowing on the ground surface, particularly the amount of rainwater that flows outside a partitioned area. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic flow diagram showing a ground improvement method according to an embodiment of the present invention. [Figure 2] FIG. 2 is a partially omitted vertical cross-sectional view showing a ground improvement structure in the process of being formed by the ground improvement method shown in FIG. 1. [Figure 3] FIG. 2 is a partially omitted vertical cross-sectional view showing a ground improvement structure formed by the ground improvement method shown in FIG. 1. [Figure 4] FIG. 2 is a partially omitted plan view showing a ground improvement structure formed by the ground improvement method shown in FIG. 1. [Figure 5] FIG. 10 is a partially omitted vertical cross-sectional view showing a ground improvement structure formed by a ground improvement method according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] [First embodiment] An embodiment (first embodiment) of the present invention will be described in detail below with reference to Figures 1 to 4. However, the description of the components described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to the following content as long as it does not deviate from the gist of the present invention.

[0018] First, an earth auger drill (not shown) or the like is used to excavate from the surface Ga of the ground G of a ground, plaza, park, or other structure that is the target of the ground improvement method, toward the ground G, to form a plurality of vertical holes P extending vertically into the ground G (step S100). Here, the vertical holes P are formed so that their deepest parts reach the gravel layer 20 (see FIG. 2).

[0019] In this embodiment, the vertical hole P has a generally cylindrical shape with a diameter of about 20 cm, but the diameter is not limited to this size, and the shape is not particularly limited either. For example, the vertical hole P may have a generally rectangular prism shape with a planar shape of about 20 cm x about 20 cm.

[0020] Next, after forming a plurality of vertical holes P, the ground improvement material 11 is poured into each of the vertical holes P from above ground (step S200). The ground improvement material 11 is formed by mixing and kneading crushed stone, a solidification material, an agglomerating agent, and water. The blending amounts (mixing ratios) of each component such as crushed stone and solidification material that make up the ground improvement material 11 can be set arbitrarily depending on the construction conditions, etc., as long as they can form columnar bodies with water permeability in the ground. Furthermore, there are no limitations on the type of agglomerating agent, but it is desirable that the agent contain a polymer compound consisting of a complex of magnesium salt of acrylic acid / dimethylaminoethyl methacrylate copolymer and polyethyleneimine. In this embodiment, we used a product called "SS-M1" from Global Research Institute, Ltd., diluted 10 to 50 times with water.

[0021] Then, when the soil improvement material 11 is poured in until it reaches the surface Ga of the ground G, a pillar-shaped body 10 (see FIG. 3) having a substantially cylindrical shape that conforms to the internal shape of the vertical hole P is formed in the vertical hole P (step S300). Note that the pillar-shaped body 10 is formed by packing the soil improvement material 11 into the vertical hole P until it reaches the surface Ga of the ground G, so that a sturdy pillar-shaped body 10 with high friction resistance can be formed even if the ground G is soft.

[0022] Then, the roadbed improvement material 30 is laid on the ground G and the pillars 10 (step S400), and finally, the soil improvement material 40 is laid on the laid roadbed improvement material 30 (step S500). Here, the roadbed improvement material 30 is formed by mixing and kneading crushed stone, a solidification material, an agglomeration agent, and water. On the other hand, the soil improvement material 40 is formed by mixing and kneading soil, a solidification material, an agglomeration agent, and water. Due to this configuration, the roadbed improvement material 30 and the soil improvement material 40 have permeability similar to that of the ground improvement material 11. As described above, the ground improvement structure 1 is formed by the ground improvement method according to this embodiment.

[0023] As mentioned above, the ground improvement method according to this embodiment forms multiple vertical holes P extending vertically in the ground G, but the positional relationship of the multiple vertical holes P (multiple columnar bodies 10) can be designed arbitrarily depending on the size of the construction site, construction conditions, etc. For example, in the example shown in Fig. 4, a plurality of pillars 10 are formed in a regular positional relationship in a plaza S having areas A and B. Specifically, in area A of the plaza S, pillars 10 are formed in three rows of "four," "three," and "four." On the other hand, in area B, pillars 10 are formed along the periphery of area B.

[0024] 1 further includes a step of providing a gutter T (see FIG. 4) around the periphery of the areas A and B to treat rainwater overflowing from the areas A and B. Furthermore, the gutter T is provided with an outlet Ta for discharging (draining) the rainwater that has flowed along the gutter T into a river or waterway. Therefore, the ground improvement structure 1 is arranged so that multiple columnar bodies 10 fit within the partitioned areas A and B, and a gutter T is provided on the periphery of areas A and B to treat rainwater overflowing from areas A and B.

[0025] By configuring the ground improvement structure 1 in this way, even in the event of heavy rain, rainwater first flows through the gutter T and is discharged (drained) from the outlet Ta of the gutter T. Then, rainwater that cannot be treated by the gutter T alone accumulates on the surface of the plaza S, but the ground improvement structure 1 formed in the plaza S allows it to be drained underground (into the ground).

[0026] That is, rainwater first permeates the soil improvement material 40 and roadbed improvement material 30 of the ground improvement structure 1, and then further permeates into the columnar body 10. Here, because the columnar body 10 has a permeable aggregate structure with continuous voids, the rainwater passes through the columnar body 10 and flows into the gravel layer 20. The gravel layer formed in the ground is a highly permeable stratum (aquifer) that allows water to pass through easily. Therefore, even if rainwater that cannot be treated above ground due to heavy rain passes through the columnar body 10 and flows into the gravel layer 20, it can be sent underground to the sea.

[0027] In addition, the ground improvement structure 1 according to this embodiment is provided by layering the roadbed improvement material 30 and the soil improvement material 40 on the ground G, so it is possible to freely arrange the layout on the ground improvement structure 1. In particular, since the soil improvement material 40 can be made suitable for planting, it is possible to plant various trees and flowers on the ground improvement structure 1 depending on the environment and use of the construction target of the ground improvement method according to this embodiment. Therefore, by using the ground improvement method and ground improvement structure according to this embodiment, green infrastructure can be further promoted.

[0028] [Second embodiment] Next, another embodiment (second embodiment) of the present invention will be described in detail with reference to Figure 5, but parts that are the same as those in the configuration described with reference to Figures 1 to 4 will be given the same symbols and detailed descriptions thereof will be omitted.

[0029] A ground improvement method according to another embodiment of the present invention is used in places paved with paving materials such as concrete or asphalt, such as parking lots and outdoor facilities. In this ground improvement method, similar to the above-described step S100 (see FIG. 1), an earth auger drill or the like is used to excavate from the surface Ga of the ground G toward the ground G, forming a plurality of vertical holes P extending vertically in the ground G, but in this case, the roadbed 50 and the paving material 60, such as concrete or asphalt, laid on the surface 50a of the roadbed 50 are excavated together to form the vertical holes P (see FIG. 5).

[0030] Then, similar to the above-mentioned steps S200 and S300 (see FIG. 1), soil improvement material 11 is poured from the ground into each of the vertical holes P until it reaches a height approximately flush with the surface 60a of the paving material 60, forming approximately cylindrical pillars 10 in the vertical holes P. This makes it possible to form a ground improvement structure 2 comprising a plurality of pillars 10 and paving material 50. Therefore, according to the ground improvement method of another embodiment of the present invention, even in places such as parking lots and outdoor facilities that are paved with low-permeability concrete, it is possible to improve the ground in question to make it resistant to heavy rain.

[0031] The paving material 60 in the ground improvement structure 2 may be permeable concrete or asphalt, and is not limited to concrete or asphalt. For example, the ground improvement method according to another embodiment of the present invention can be used for a place paved with a resin-based mixed pavement or a wood-based pavement.

[0032] Although the embodiment of the present invention has been described above, the described embodiment is merely an example, and the present invention is not limited to the contents thereof as long as it does not deviate from the gist of the present invention. For example, the shapes and depths of the multiple vertical holes P and the shapes and vertical lengths of the pillars 10 may be different from one another. Even at the same construction site, the depth to the gravel layer may differ depending on where the vertical holes are excavated, so the depth of the vertical holes P and the vertical lengths of the pillars 10 can be designed as desired for each excavated location. Furthermore, even at the same construction site, in places where water is particularly likely to accumulate, vertical holes P and pillars 10 with larger diameters and other sizes can be formed to improve drainage capacity.

[0033] In addition, it is also possible to provide a groove (drainage groove) connecting the multiple pillars 10 (vertical holes P) formed together. For example, in the ground improvement structure 1 shown in Fig. 4, a drainage groove can be provided from one pillar 10 to multiple other pillars 10. This allows rainwater to flow down the drainage groove, so that the rainwater can be distributed so that the drainage amount of the multiple pillars 10 (vertical holes P) is equal, and the drainage efficiency of the entire ground improvement structure 1 can be improved.

[0034] Furthermore, the configuration of the ground improvement structure may be a structure in which only the soil improvement material 40 is provided on the ground G, or a structure in which neither the roadbed improvement material 30 nor the soil improvement material 40 is provided. In the case of a structure in which neither the roadbed improvement material 30 nor the soil improvement material 40 is provided, the columnar bodies 10 provided in the ground are easy to see, which makes it easier to lay out the construction site, etc.

[0035] The type of ground improvement method to be used and the type of ground improvement structure to be adopted can be appropriately designed by the contractor depending on the construction location, construction conditions, purpose, etc. In addition, the ground improvement method and ground improvement structure of the present invention can of course exert the above-mentioned effects even when large amounts of water flow in due to causes other than rainwater, such as a tsunami or a malfunctioning fire hydrant. [Industrial Applicability]

[0036] The present invention relates to a method for improving the ground to make it resistant to heavy rain and a ground improvement structure formed by this ground improvement method, which can be widely used in construction at various sites such as grounds, plazas, parks, and parking lots, and is therefore industrially useful. [Explanation of symbols]

[0037] 1,2 Ground improvement structure 10 columnar body 11 Ground improvement materials 20 Gravel layer 30 Roadbed improvement material 40 Soil conditioner 50 Roadbed 50a Roadbed surface 60 Paving materials 60a paving surface P vertical hole G Ground Ga Ground surface S Square A,B Square area T gutter Ta Gutter outlet

Claims

1. excavating a plurality of vertical holes in the ground down to a gravel layer; and a step of pouring a soil improvement material into the vertical hole to form a columnar body having a granular structure with continuous lattice-like or net-like voids in the ground and having water permeability, A ground improvement method in which the ground improvement material contains one or more of crushed stone, granular soil, and earth material, a solidification material, a granulation agent, and water.

2. A step of laying a roadbed improvement material on the ground and on the pillars; The ground improvement method according to claim 1, further comprising the step of laying a soil improvement material on the laid roadbed improvement material.

3. 2. The ground improvement method according to claim 1, wherein the granulating agent contains a polymer compound consisting of a complex of a magnesium salt of an acrylic acid / dimethylaminoethyl methacrylate copolymer and polyethyleneimine.

4. A plurality of the vertical holes are excavated so as to fit within a partitioned area; The ground improvement method according to any one of claims 1 to 3, further comprising providing a gutter around the periphery of the area to treat rainwater overflowing from the area.

5. The columnar structure is formed by pouring soil improvement materials into a plurality of vertical holes that reach the gravel layer excavated in the ground, and has a granular structure with continuous voids that form a lattice or net shape, and is permeable. The ground improvement structure is made by solidifying the columnar bodies using a ground improvement material containing one or more of crushed stone, granulated sand, and earth, a solidification material, a granulation agent, and water.

6. A roadbed improvement material laid on the ground and on the columnar body; The ground improvement structure according to claim 5, further comprising a soil improvement material laid on the roadbed improvement material.

7. 6. The ground improvement structure according to claim 5, wherein the granulating agent contains a polymer compound consisting of a complex of a magnesium salt of an acrylic acid / dimethylaminoethyl methacrylate copolymer and polyethyleneimine.

8. the plurality of pillars are provided so as to be contained within a partitioned region, The ground improvement structure according to any one of claims 5 to 7, wherein a gutter for treating rainwater overflowing from the area is provided on the periphery of the area.

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