JP7627617B2 - Lightweight embankment structure, foam block, and method for constructing lightweight embankment structure - Google Patents

Description

The present invention relates to a lightweight embankment structure, and in particular to a lightweight embankment structure, foam blocks, and a method for constructing a lightweight embankment structure that is placed in an excavation trench formed by excavating the ground or the like.

When constructing embankment structures, a lightweight embankment method (for example, the EPS method using expanded polystyrene blocks) is known in which synthetic resin foam, which has excellent properties such as light weight, shock absorption, and ease of processing, is used as the embankment material. This lightweight embankment method involves piling up block-shaped synthetic resin foam according to certain rules, and then covering the outer surface with soil or sand to construct an embankment structure.

Patent Document 1 discloses a structure for protecting buried resin pipes buried underground, which aims to provide a structure that is excellent in protection and workability, and that allows easy detection of buried pipes or buried objects that require repair during restoration work. The structure is for protecting buried resin pipes buried underground, and a foamed resin protective block is installed above the buried pipe to fill the area between the buried pipe and the underside of the pavement layer, which requires heavy machinery for removal. When the pavement layer is removed, the protective block below is exposed, and when the protective block is removed, the buried pipe below is exposed.

According to the lightweight embankment structure disclosed in Patent Document 1, if a buried pipe is damaged due to a large-scale disaster such as an earthquake, the protective block body is exposed when the pavement layer is removed with heavy machinery, making it easy to know that the buried pipe is buried there. In that case, the buried pipe is exposed when the protective block body is removed, making it easy to find and repair damaged areas of the buried pipe or other areas that need repair.

JP 2012-92239 A

However, in the case of the lightweight embankment structure described above, in order to remove the foamed resin protective block, it is necessary to first remove the surrounding soil and sand, which is a large-scale task that requires the use of heavy machinery, making the removal work cumbersome. Furthermore, in disaster sites and other locations where it is difficult to access heavy machinery, it can be difficult to remove the protective block by hand, which can cause problems in repairing damaged areas of buried pipes.

The present invention has been made in consideration of the actual situation of the background technology described above, and aims to provide a lightweight embankment structure, a foam block, and a method for constructing a lightweight embankment structure that facilitates the removal of the constructed foam block assembly.

In order to solve the above problems, the present invention provides a lightweight embankment structure, a foam block, and a method for constructing a lightweight embankment structure as described in the following [1] to [8].
[1] A lightweight embankment structure comprising a base and a foam block assembly formed on the base by laminating a plurality of foam block layers composed of rectangular parallelepiped foam blocks,
At least one of the foam block layers includes a rectangular parallelepiped composite foam block composed of two or more divided foam blocks,
The rectangular parallelepiped composite foam block is divided into two or more parts from the upper surface to the lower surface of the rectangular parallelepiped composite foam block, and each of the divided foam blocks is a quadrangular columnar foam block having a bottom surface with a substantially trapezoidal shape,
In each bottom surface of the quadrangular columnar foamed block, a pair of opposing base sides are approximately parallel to each other, and at least one end of a first base side of the pair of opposing base sides is located inwardly without protruding beyond both ends of a second base side, and a side edge is provided between the first base side and the second base side, the side edge expanding toward the second base side ,
The rectangular parallelepiped composite foam block is characterized in that it is composed of two or more of the rectangular columnar foam blocks arranged with the side surfaces including the expanding sides of the rectangular columnar foam blocks facing each other .
Lightweight embankment structure.
[2] The lightweight embankment structure described in [1] above, characterized in that at least one of the angles formed between one of the upper and lower surfaces of the quadrangular columnar foam block and the side surfaces of two quadrangular columnar foam blocks intersecting with said one of the upper and lower surfaces is greater than or equal to 60 degrees and less than 90 degrees.
[3] The lightweight embankment structure described in [1] or [2] above, characterized in that the two or more rectangular columnar foam blocks constituting the rectangular composite foam block are connected by connectors .
[4] The lightweight embankment structure described in any one of [1] to [3] above, characterized in that a sheet-like material is interposed between the opposing faces of the two or more quadrangular columnar foam blocks that constitute the rectangular parallelepiped composite foam block.
[5] A lightweight embankment structure as described in any one of [1] to [4] above, characterized in that the lightweight embankment structure is placed in an excavation trench formed by excavating the ground.
[6] The lightweight embankment structure described in [5] above, characterized in that in the foam block assembly, the column axis direction of the quadrangular columnar foam blocks is arranged along the extension direction of the excavation trench.
[7] A foamed block used in the construction of a lightweight embankment structure according to any one of [1] to [6] above,
The foam block is a rectangular parallelepiped composite foam block composed of two or more divided foam blocks,
The rectangular parallelepiped composite foam block is divided into two or more parts from the upper surface to the lower surface of the rectangular parallelepiped composite foam block, and each of the divided foam blocks is a quadrangular columnar foam block having a bottom surface with a substantially trapezoidal shape,
In each bottom surface of the quadrangular columnar foamed block, a pair of opposing base sides are approximately parallel to each other, and at least one end of a first base side of the pair of opposing base sides is located inwardly without protruding beyond both ends of a second base side, and a side edge is provided between the first base side and the second base side, the side edge expanding toward the second base side ,
The rectangular parallelepiped composite foam block is constructed by arranging two or more of the quadrangular columnar foam blocks with their side surfaces including the expanding side edges facing each other.
Foam block.
[8] A method for constructing a lightweight embankment structure, comprising laminating a plurality of foam block layers made of rectangular parallelepiped foam blocks on a base in an excavation trench formed by excavating the ground to form a foam block assembly,
At least one of the foam block layers is composed of a foam block layer including a rectangular parallelepiped composite foam block composed of two or more divided foam blocks,
The rectangular parallelepiped composite foam block is divided into two or more parts from the upper surface to the lower surface of the rectangular parallelepiped composite foam block, and each of the divided foam blocks is a quadrangular columnar foam block having a bottom surface with a substantially trapezoidal shape,
In each bottom surface of the quadrangular columnar foamed block, a pair of opposing base sides are approximately parallel to each other, and at least one end of a first base side of the pair of opposing base sides is located inwardly without protruding beyond both ends of a second base side, and a side edge is provided between the first base side and the second base side, the side edge expanding toward the second base side,
The rectangular parallelepiped composite foam block is constructed from two or more of the quadrangular columnar foam blocks by arranging the side surfaces including the expanding sides of the quadrangular columnar foam blocks so as to face each other,
The rectangular parallelepiped composite foam block is disposed in the excavation trench such that the column axis direction of the quadrangular columnar foam block coincides with the extension direction of the excavation trench.
A method for constructing lightweight earth fill structures.

The present invention described above provides a lightweight embankment structure, a foam block, and a method for constructing a lightweight embankment structure that allows for easy removal of the constructed foam block assembly.

1 is a cross-sectional view showing one embodiment of a lightweight embankment structure according to the present invention. 1A to 1C are diagrams showing various shapes of the bottom surface (cross section perpendicular to the column axis) of the quadrangular columnar foam block according to the present invention. FIG. 13 is a conceptual cross-sectional view showing a state in which rectangular columnar foam blocks are connected using an L-shaped pin. 1 is a conceptual cross-sectional view showing adjacent rectangular columnar foam blocks connected vertically and horizontally using fastening fittings. FIG. FIG. 2 is a perspective view showing a state in which a sheet is interposed between quadrangular columnar foam blocks. This is a diagram showing the work process for dismantling the constructed lightweight embankment structure. FIG. 4 is a cross-sectional view showing another embodiment of the lightweight embankment structure according to the present invention.

The lightweight embankment structure, foam block, and method for constructing the lightweight embankment structure according to the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, the lightweight embankment structure of the present invention is a lightweight embankment structure S that includes a base G and a foam block assembly A formed on the base G and consisting of multiple laminated foam block layers made of rectangular parallelepiped foam blocks.

The base G is a portion on which an embankment made of foam block aggregate A is constructed. In the embodiment shown in FIG. 1, the base G is formed at the bottom of an excavation trench D formed by excavating the ground to bury the buried pipe B. The excavation trench D preferably has a trench width of 0.5 m or more and 2 m or less. The excavation trench D preferably has a trench height of 1 m or more and 5 m or less, more preferably 1 m or more and 3 m or less. The buried pipe B is disposed along the excavation trench D. A protective body C for protecting the buried pipe B is disposed around the buried pipe B. The protective body C can be, for example, crushed stone, soil, concrete, foam block, or the like. The base G including the buried pipe B and the protective body C is formed at the bottom of the excavation trench D. The buried pipe B is, for example, a cable protection pipe through which various cables such as gas pipes, water supply and sewerage pipes, hot water supply pipes, power cables, and communication cables are inserted.

The constructed foam block assembly A is backfilled with soil H, etc., and above it is formed a pavement layer E, which will serve as the roadbed if necessary. The pavement layer E may be a hard layer that requires heavy machinery such as a road cutter to remove. The pavement layer E may be composed of one layer or multiple layers, with the number of layers and layer structure being determined by the purpose of the road surface, the load capacity, etc.

In the foam block assembly A, at least one of the foam block layers includes a rectangular parallelepiped composite foam block Y composed of two or more divided foam blocks (quadratic columnar foam blocks X).
The rectangular composite foam block Y is divided into two or more parts from the top to the bottom of the rectangular composite foam block, and each divided foam block is composed of a quadrangular columnar foam block X having a bottom surface (cross section perpendicular to the column axis) of a substantially trapezoidal shape (see FIG. 2).
In the foam block assembly A, it is preferable that the upper and lower surfaces (top and bottom surfaces) of the rectangular parallelepiped composite foam block Y are arranged approximately horizontally. The side surfaces on the bottom side of the quadrangular columnar foam block X form the upper and lower surfaces of the rectangular parallelepiped composite foam block Y.

As shown in FIG. 2, the quadrangular columnar foam block X has a quadrangular columnar shape in which the angle α between one of the upper and lower faces of the quadrangular columnar foam block X and the two side faces of the quadrangular columnar foam block X that intersect with the upper and lower faces is 90 degrees or less, and the shape of the bottom face (cross section perpendicular to the column axis) is approximately trapezoidal.

In other words, as shown in FIG. 2 , the quadrangular columnar foamed block X has a pair of opposing base sides 1, 2 that are approximately parallel to each other on the bottom surface (cross section perpendicular to the column axis), and at least one end of a first base side (short side of the base side) 1 of the pair of opposing base sides 1, 2 is located inwardly without protruding beyond both ends of a second base side (long side of the base side) 2, and has a side side 3 between the first base side 1 and the second base side 2 that expands toward the second base side 2.
The quadrangular columnar foamed block X has a substantially trapezoidal bottom surface defined by a long side and a short side.
The angle α can also be expressed as the angle formed by the side surface on the long side of the base of the quadrangular columnar foam block and the adjacent side surfaces on the long sides of the two bases that intersect with the side surface on the long side of the base.
As shown in Figures 2(a), (c), (d) and (e), the rectangular columnar foam block X may be formed with only one expanding side edge 3 and the other side edge formed vertically, or as shown in Figure 2(b), both sides 3 may be formed with expanding sides 3. Also, as shown in Figures 2(f) and (g), the rectangular columnar foam block X may be formed with the side edges 3 expanding in a stepped manner.
However, from the viewpoints of facilitating the processing of the quadrangular columnar foamed block X and enhancing the workability and removal property of the foamed block aggregate A, it is preferable that the sides of the quadrangular columnar foamed block X are straight, and it is more preferable that the shape of the bottom surface of the quadrangular columnar foamed block X is trapezoidal. In addition, it is preferable that the quadrangular columnar foamed block X is a right square columnar foamed block.

The rectangular composite foam block Y is composed of two or more divided foam blocks (quadratic columnar foam blocks X) by abutting the expanding side edges 3 of the quadrangular columnar foam blocks X (side surfaces including the expanding side edges of the quadrangular columnar foam blocks X). For example, the rectangular composite foam block Y may be a combination of three quadrangular columnar foam blocks X having the bottom shapes shown in (a), (b), and (c) of FIG. 2, a combination of two quadrangular columnar foam blocks X having the bottom shapes shown in (d) and (e) of FIG. 2, or a combination of two quadrangular columnar foam blocks X having the bottom shapes shown in (f) and (g) of FIG. 2. From the viewpoint of further improving the workability and removal property of the foam block assembly A, it is preferable that the rectangular composite foam block Y is composed of two or three divided foam blocks.
In the foam block assembly A, the rectangular columnar foam blocks X constituting the rectangular columnar composite foam block Y are arranged such that the side faces of the rectangular columnar foam blocks X that include two base sides 1 or two base sides 2 that face each other in the column axis direction become the upper and lower faces of the rectangular columnar composite foam block Y.
In the foam block assembly A according to the embodiment shown in FIG. 1, all the laminated foam block layers are composed of a rectangular parallelepiped composite foam block Y formed by combining three quadrangular columnar foam blocks X having the bottom shapes shown in FIGS. 2(a), 2(b), and 2(c).

From the viewpoint of facilitating the processing of the quadrangular columnar foam blocks X and enhancing the workability and removability of the foam block assembly A, it is preferable that the rectangular composite foam block Y is formed from two quadrangular columnar foam blocks X, one of which is a sloped surface and the other a vertical surface (side surfaces other than the bottom side surface of the quadrangular columnar foam block X) including the side edges of the quadrangular columnar foam blocks X (combination of (d) and (e) in Figure 2), or that the rectangular composite foam block Y is formed from two quadrangular columnar foam blocks X, one of which is a sloped surface and the other a vertical surface, including the side edges of the quadrangular columnar foam block X, and one quadrangular columnar foam block X, both of which are sloped surfaces including the side edges of the quadrangular columnar foam block X (combination of (a) , (b) and (c) in Figure 2). In addition, from the viewpoint of more easily preventing the floating of the quadrangular columnar foam block X due to lateral soil pressure, etc., it is more preferable that the rectangular composite foam block Y is formed from two quadrangular columnar foam blocks X, one of which is an inclined surface and the other of which is a vertical surface, and one quadrangular columnar foam block X, both of which are inclined surfaces (the combination of (a), (b), and (c) in FIG. 2).

The foam block assembly A includes a plurality of quadrangular columnar foam blocks X, each having a substantially trapezoidal bottom surface, and the column axis direction of the quadrangular columnar foam blocks X is aligned with the extension direction of the excavation trench D.

At least one of the angles α between one of the upper and lower faces of the quadrangular columnar foamed block X and the side faces of the two quadrangular columnar foamed blocks X intersecting with the one of the upper and lower faces (the angle α of the corner formed by the second base edge 2 and the expanding side edge 3 intersecting with the second base edge 2 at the bottom face (cross section perpendicular to the column axis) of the quadrangular columnar foamed block X) is preferably 60 degrees or more and less than 90 degrees, and more preferably 70 degrees or more and 85 degrees or less. Since the side faces are formed at such a relatively deep angle (an angle close to vertical), when the quadrangular columnar foamed block X is placed and buried in an excavation trench D, etc., it is possible to suppress the floating of the quadrangular columnar foamed block X due to earth pressure generated laterally, and a good foamed block aggregate A can be stably formed.
From the viewpoint of more easily preventing the quadrangular columnar foamed block X from floating due to lateral earth pressure or the like, it is preferable that the rectangular composite foamed block Y includes a quadrangular columnar foamed block X in which the angles formed between one of the upper and lower faces of the quadrangular columnar foamed block X and the side faces of the two quadrangular columnar foamed blocks X intersecting with the one of the upper and lower faces are both 60 degrees or more and less than 90 degrees, and it is more preferable that the rectangular composite foamed block Y includes a quadrangular columnar foamed block X in which both of the angles are 70 degrees or more and 85 degrees or less.

In addition, the length of the long side of the base (the length of the second base 2) on the bottom surface of the quadrangular columnar foam block X is preferably 0.1 m or more and 1 m or less, and the ratio of the length of the short side of the base (the length of the first base 1) to the length of the long side is preferably 0.6 or more. A quadrangular columnar foam block X having such a shape and dimensions is preferable because it is easy to handle and is less likely to chip or crack even on the thin first base 1 side. From this perspective, the length of the long side of the base is preferably 0.2 m or more. The length of the long side of the base is preferably 0.8 m or less, more preferably 0.6 m or less, and even more preferably 0.5 m or less. The ratio of the length of the short side of the base to the length of the long side of the base is more preferably 0.7 to 0.9.

The length of the quadrangular columnar foamed block X in the column axis direction β is preferably 0.5 m or more and 3 m or less, more preferably 1 m or more and 2.5 m or less. The height of the quadrangular columnar foamed block X (the length between the first base 1 and the second base 2) is preferably 0.1 m or more and 1 m or less, more preferably 0.3 m or more and 0.8 m or less. The quadrangular columnar foamed block X having such a shape and size is excellent in handleability, and the construction workability of the foamed block aggregate A using the quadrangular columnar foamed block X and the dismantling workability of the constructed foamed block aggregate A are good. From the same viewpoint, the volume of the quadrangular columnar foamed block X is preferably 0.1 m ³ or more, more preferably 0.2 m ³ or more. The volume of the quadrangular columnar foamed block X is preferably 2 m ³ or less, more preferably 1 m ³ or less, and even more preferably 0.6 m ³ or less.

The base resin constituting the quadrangular columnar foam block X may be a thermoplastic resin or a thermosetting resin similar to the base resin constituting the rectangular parallelepiped foam block generally used in the construction of lightweight embankments. For example, examples of the thermoplastic resin include polystyrene-based resins such as polystyrene, polyolefin-based resins such as polyethylene and polypropylene, vinyl chloride-based resins, polyamide-based resins, etc., and examples of the thermosetting resin include phenol-based resins, polyurethane-based resins, etc. Among these, it is preferable to use a quadrangular columnar foam block X having a thermoplastic resin as the base resin, because of its excellent properties such as light weight, water resistance, and durability, as well as cost, and it is more preferable to use a quadrangular columnar foam block X having a polystyrene-based resin as the base resin.
The resins exemplified as the base resin constituting the quadrangular columnar foam block X can be used as the base resin constituting the foam block other than the quadrangular columnar foam block X. It is more preferable that the base resin constituting the quadrangular columnar foam block X and the base resin constituting the foam block other than the quadrangular columnar foam block X are the same type of resin.

In addition, the 10% deformation compressive stress in the height direction of the quadrangular columnar foamed block X is preferably 30 kN/ ^m2 or more, more preferably 50 kN/m2 or ^more , and even more preferably 100 kN/ ^m2 or more, from the viewpoint of suppressing deformation of the foamed block aggregate A due to load and increasing the strength of the lightweight embankment structure. The upper limit of the 10% deformation compressive stress is preferably about 600 kN/ ^m2 , and more preferably 500 kN/ ^m2 .
The 10% deformation compressive stress is a compressive stress [kN/m ² ] at a compressive strain of 10%, measured by carrying out a compression test in accordance with JIS K7220:2006.
From the viewpoint of being lightweight and having good strength, the apparent density of the quadrangular columnar foamed block X is preferably 12 kg/m3 or ^more and 100 kg/m3 ^or less, more preferably 15 kg/m3 ^{or more} and 60 kg/m3 ^or less, and even more preferably 20 kg/m3 or ^more and 50 kg/ ^m3 or less.

The method for producing the quadrangular columnar foam block X is not particularly limited, but examples include a method for producing a foamed bead molded product (quadratic columnar foam block X) having the above shape by molding foamed beads in a mold, and a method for producing a quadrangular columnar foam block X having the above shape by processing a prefabricated foam block formed into a predetermined shape by cutting or the like. Note that the foam block or quadrangular columnar foam block X may be formed by stacking multiple plate-shaped foams, etc.

The area of contact between the expanding sides 3 of the quadrangular columnar foam blocks X in the rectangular parallelepiped composite foam block Y is preferably 0.1 ^m2 to 5 ^m2 , more preferably 0.5 ^m2 to 3.5 ^m2 . It is preferable that the quadrangular columnar foam blocks X contact each other within the above-mentioned area from the viewpoint of enhancing the structural stability of the foam block assembly A to be constructed.

Moreover, the foam block layer including the rectangular parallelepiped composite foam block Y is preferably disposed in the height direction of the foam block assembly A at least in a range from the upper surface of the base G to a position that is 50% of the maximum height of the foam block assembly A. This is because the foam blocks located lower in the foam block assembly A are more difficult to remove due to the influence of earth pressure, etc., so it is preferable that a foam block layer including the rectangular parallelepiped composite foam block Y, which improves removal, is disposed in the lower portion of the foam block assembly A. When at least a part of the foam block layer is present at a position that is 50% of the maximum height, the foam block layer is deemed to be disposed in a range up to a position that is 50% of the maximum height.
From this viewpoint, the proportion of the number of foam block layers including rectangular composite foam blocks Y arranged in the height direction of the foam block assembly A in the range from the upper surface of the base G to a position that is 50% of the maximum height of the foam block assembly A is preferably 50% or more, more preferably 60% or more, and even more preferably 80% or more, when the number of foam block layers existing in the range up to a position that is 50% of the maximum height of the foam block assembly A is taken as 100%.
From the same viewpoint, the volume ratio of the quadrangular columnar foamed blocks X constituting the rectangular parallelepiped composite foamed block Y in the foam block assembly A is preferably about 20% or more, more preferably 25% or more, and even more preferably 30% or more. On the other hand, from the viewpoint of improving the workability of constructing the foam block assembly A and from the viewpoint of improving the structural stability of the foam block assembly A, the volume ratio of the quadrangular columnar foamed blocks X constituting the rectangular parallelepiped composite foamed block Y in the foam block assembly A is preferably 85% or less, and more preferably 70% or less.

In the height direction of the foam block assembly A, it is preferable that the angle α of the corners of the quadrangular columnar foam block X at the bottom surface is smaller in the foam block layer including the rectangular parallelepiped composite foam block Y located on the lower layer side than in the foam block layer including the rectangular parallelepiped composite foam block Y located on the upper layer side. The foam block layer located on the lower layer side of the foam block assembly A is more susceptible to the influence of earth pressure and the like generated on the sides when it is placed and buried in an excavation trench D, etc., so that the quadrangular columnar foam block X tends to be difficult to pull out. However, by forming the angle α of the corners of the quadrangular columnar foam block X in the foam block layer including the rectangular parallelepiped composite foam block Y located on the lower layer side relatively shallow, the pull-out property of the quadrangular columnar foam block X can be improved. From this perspective, in the height direction of the foam block assembly A, the angle α of the corner at the bottom surface of the quadrangular columnar foam block X in the foam block layer containing the rectangular parallelepiped composite foam block Y located on the bottom layer side is preferably smaller than the angle α of the corner at the bottom surface of the quadrangular columnar foam block X in the foam block layer containing the rectangular parallelepiped composite foam block Y located on the top layer side, and is more preferably 1 to 10 degrees smaller.

In constructing the foam block assembly A having a foam block layer including the above-mentioned rectangular composite foam block Y, it is preferable that the rectangular composite foam block Y is connected to the rectangular composite foam block Y by a connector. In this case, the rectangular composite foam block Y can be easily transported and the workability of the rectangular composite foam block Y can be improved. Examples of the connector include an L-shaped pin and a fastening metal fitting. For example, as shown in FIG. 3, when the expanding sides 3 of the rectangular composite foam block X are abutted against each other to construct the rectangular composite foam block Y, it is preferable to connect the abutting expanding sides 3 by piercing the L-shaped pin 10, or to connect the adjacent rectangular composite foam blocks X vertically and horizontally by using a double-claw type fastening metal fitting 20 as shown in FIG. 4, in order to construct a stable foam block assembly A.
In order to improve ease of construction and removal of the quadrangular columnar foam block X, the quadrangular columnar foam block X may be provided with a handle.

In order to construct a foam block assembly A that is easier to dismantle, it is preferable that a sheet-like material is interposed between the mating surfaces of the rectangular columnar foam blocks X in the rectangular composite foam block Y. In this case, it is preferable that the sheet-like material is exposed to the outside of the rectangular composite foam block Y. As the sheet-like material, a sheet that reduces the friction coefficient can be used. For example, as shown in FIG. 5, when constructing the rectangular composite foam block Y, it is preferable to sandwich a sheet 30 between the rectangular columnar foam block X located in the center in order to make the foam block easier to pull out. The material of the sheet to be interposed is preferably one that has tensile strength and flexibility, such as a polyethylene sheet or a polypropylene sheet. These sheets may be attached to the rectangular columnar foam blocks X in advance, or the sheet may be sandwiched between the rectangular columnar foam blocks X at the site.

The lightweight embankment structure S according to the present invention can be constructed, for example, as follows:

First, excavate the soil where the buried pipe will be installed to form an excavation trench D, and then install the buried pipe B at the bottom of the excavation trench D. The excavation trench D is formed to be much wider than the outer diameter of the buried pipe B, with a certain amount of space left on both the left and right sides of the buried pipe B. Then, a protective body C, etc. is placed around the buried pipe B, and a base G is formed on the bottom of the excavation trench D.

Next, on the base G of the excavation trench D, a foam block assembly A is constructed by laminating a plurality of foam block layers each composed of a plurality of rectangular parallelepiped foam blocks.
Here, at least one layer of the foam block layer is composed of a foam block layer including a rectangular parallelepiped composite foam block Y composed of two or more divided foam blocks (quadratic columnar foam blocks X). In constructing this foam block assembly A, the rectangular parallelepiped composite foam block Y is divided into two or more parts from the upper surface to the lower surface of the rectangular parallelepiped composite foam block, and the divided foam blocks are composed of quadrangular columnar foam blocks X having a bottom surface with a substantially trapezoidal shape. In the rectangular parallelepiped composite foam block Y, the angle α formed between one of the upper and lower surfaces of the quadrangular columnar foam block X and the side surfaces of the two quadrangular columnar foam blocks intersecting with the one of the upper and lower surfaces is both 90 degrees or less.
The rectangular parallelepiped composite foam block Y is formed by abutting the expanding side edges 3 of two or more of the above-mentioned quadrangular columnar foam blocks X. In the foam block assembly A, the upper and lower surfaces (top and bottom surfaces) of the rectangular parallelepiped composite foam block Y are arranged approximately horizontally.
Then, the rectangular parallelepiped composite foam block Y is placed in the excavation trench D with the column axis direction β of the quadrangular columnar foam block X aligned with the extension direction of the excavation trench D. In this manner, at least one foam block layer including the rectangular parallelepiped composite foam block Y is formed. When constructing the foam block assembly A, rectangular parallelepiped foam blocks that are generally used in the construction of lightweight embankments are stacked and placed as necessary to construct the foam block assembly A. In the foam block assembly A according to the embodiment shown in FIG. 1, all three stacked foam block layers are composed of rectangular parallelepiped composite foam blocks Y formed by combining quadrangular columnar foam blocks X.

Next, soil and sand H etc. are backfilled around the constructed foam block assembly A, and a paving layer E that will serve as the roadbed as needed is formed on top, completing the lightweight embankment structure S.

The lightweight embankment structure, foam block, and method for constructing a lightweight embankment structure according to the present invention described above facilitates the removal of the constructed foam block assembly A. This will be explained below using the example of the dismantling of the lightweight embankment structure S shown in Figure 1.

First, as shown in FIG. 6(a), the pavement layer E of the lightweight embankment structure S is removed using heavy machinery or the like. When the pavement layer E is removed, the foam block assembly A is exposed, so the worker can easily determine the position of the foam block assembly A to be removed.

6(b), the central quadrangular columnar foam block X is removed first from the foam block layer including the rectangular parallelepiped composite foam block Y composed of the uppermost quadrangular columnar foam blocks X. The central quadrangular columnar foam block X is not easily affected by earth pressure or friction with other foam blocks due to its shape, and can be easily removed by hand.
In addition, in conventional methods such as that described in Patent Document 1, when removing a protective block made of foamed resin, if the surrounding soil is not removed, it becomes difficult to remove the protective block due to earth pressure and friction between the soil and the protective block, and the removal work is complicated as the work requires large-scale heavy machinery. However, the present invention makes it possible to make the removal work easier.

Next, as shown in FIG. 6(c), the rectangular columnar foam blocks X at both ends of the foam block layer including the rectangular composite foam block Y composed of the top layer of multiple rectangular columnar foam blocks X are removed. The removal of the rectangular columnar foam blocks X at both ends is performed by moving the rectangular columnar foam blocks X at the ends toward the center, i.e., by removing them away from the surrounding soil and sand H. This makes it difficult to be affected by earth pressure or friction with other foam blocks, and also allows for easy removal by manual force.

Next, as shown in FIG. 6(d), the rectangular columnar foam blocks X constituting the second and bottom layers are removed in the same manner as described above, and the crushed stone or protective material C around the buried pipe B is removed to expose the buried pipe B, which can then be repaired.

As described above, when the lightweight embankment structure, foam blocks, and method for constructing a lightweight embankment structure according to the present invention are used as an embankment structure to fill in the space above buried pipes that need to be repaired due to a large-scale disaster such as an earthquake, the embankment can be easily removed by hand without using heavy machinery. In addition, because little damage is caused to the foam blocks, which are the embankment material, during removal, the removed foam blocks can be easily reused to construct a lightweight embankment structure.

Although an embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and it is natural that various modifications and changes are possible within the scope of the lightweight embankment structure, foam block, and method for constructing a lightweight embankment structure as the technical concept of the present invention described in the claims.
For example, in the above embodiment, the light-weight embankment structure S is constructed in a relatively narrow and low excavation trench D in which a buried pipe B is arranged. However, the present invention can also be applied to a large-scale light-weight embankment structure that is wide and high and constructed on an underground facility as shown in FIG. 7(a), and to a light-weight embankment structure that is constructed on a stepped base such as the back of a bridge abutment as shown in FIG. 7(b). In addition, the light-weight embankment structure in FIG. 7(a) and (b) includes a rectangular parallelepiped composite foam block Y formed by combining the square columnar foam blocks X shown in FIG. 2(d) and (e) in the foam block layer. FIG. 7 illustrates the construction of a foam block assembly in the middle of dismantling. In FIG. 7, the same members and parts as those in FIG. 1 are given the same reference numerals, O is a rectangular parallelepiped foam block generally used as an embankment material, and F is an underground facility such as an underground parking lot or an underground water tank.

The lightweight embankment structure, foam blocks, and method for constructing a lightweight embankment structure according to the present invention facilitate the removal of the constructed foam block assembly, and can therefore be widely used to construct embankment structures that are expected to require removal for repairs or other reasons after construction.

G: Base A: Foam block assembly B: Buried pipe C: Protective body D: Excavation trench E: Pavement layer H: Crushed stone, soil, etc. S: Lightweight embankment structure X: Square columnar foam block 1, 2: A pair of opposing bases 1: First base (short side of base)
2...Second base (longer side of the base)
3...Expanding side α...Angle between one of the upper and lower surfaces of the rectangular columnar foam block and the side surface of the two rectangular columnar foam blocks intersecting with one of the upper and lower surfaces β...Column axis direction of the rectangular columnar foam block Y...Rectangular parallelepiped composite foam block composed of two or more divided foam blocks (rectangular columnar foam blocks) 10...L-shaped pin 20...Fastening metal fitting 30...Sheet O...Rectangular parallelepiped foam block F...Underground facility

Claims (8)

A lightweight embankment structure comprising a base and a foam block assembly formed on the base by laminating a plurality of foam block layers each composed of a rectangular parallelepiped foam block,
At least one of the foam block layers includes a rectangular parallelepiped composite foam block composed of two or more divided foam blocks,
The rectangular parallelepiped composite foam block is divided into two or more parts from the upper surface to the lower surface of the rectangular parallelepiped composite foam block, and each of the divided foam blocks is a quadrangular columnar foam block having a bottom surface with a substantially trapezoidal shape,
In each bottom surface of the quadrangular columnar foamed block, a pair of opposing base sides are approximately parallel to each other, and at least one end of a first base side of the pair of opposing base sides is located inwardly without protruding beyond both ends of a second base side, and a side edge is provided between the first base side and the second base side, the side edge expanding toward the second base side ,
The rectangular parallelepiped composite foam block is characterized in that it is composed of two or more of the rectangular columnar foam blocks arranged with the side surfaces including the expanding sides of the rectangular columnar foam blocks facing each other .
Lightweight embankment structure. The lightweight embankment structure according to claim 1, characterized in that at least one of the angles formed between one of the upper and lower faces of the quadrangular columnar foam block and the side faces of the two quadrangular columnar foam blocks intersecting with the upper and lower faces is 60 degrees or more and less than 90 degrees. 3. The lightweight embankment structure according to claim 1, wherein the two or more rectangular columnar foam blocks constituting the rectangular parallelepiped composite foam block are connected by connectors . A lightweight embankment structure as described in any one of claims 1 to 3, characterized in that a sheet-like material is interposed between the opposing faces of the two or more quadrangular columnar foam blocks that constitute the rectangular composite foam block . The lightweight embankment structure according to any one of claims 1 to 4, characterized in that the lightweight embankment structure is placed in an excavation trench formed by excavating the ground. The lightweight embankment structure according to claim 5, characterized in that in the foam block assembly, the column axis direction of the quadrangular columnar foam blocks is arranged along the extension direction of the excavation trench. A foam block used for constructing a lightweight embankment structure according to any one of claims 1 to 6,
The foam block is a rectangular parallelepiped composite foam block composed of two or more divided foam blocks,
The rectangular parallelepiped composite foam block is divided into two or more parts from the upper surface to the lower surface of the rectangular parallelepiped composite foam block, and each of the divided foam blocks is a quadrangular columnar foam block having a bottom surface with a substantially trapezoidal shape,
In each bottom surface of the quadrangular columnar foamed block, a pair of opposing base sides are approximately parallel to each other, and at least one end of a first base side of the pair of opposing base sides is located inwardly without protruding beyond both ends of a second base side, and a side edge is provided between the first base side and the second base side, the side edge expanding toward the second base side ,
The rectangular parallelepiped composite foam block is constructed by arranging two or more of the quadrangular columnar foam blocks with their side surfaces including the expanding side edges facing each other.
Foam block. A method for constructing a lightweight embankment structure, comprising laminating a plurality of foam block layers made of rectangular parallelepiped foam blocks on a base in an excavation trench formed by excavating the ground to form a foam block assembly, comprising:
At least one of the foam block layers is composed of a foam block layer including a rectangular parallelepiped composite foam block composed of two or more divided foam blocks,
The rectangular parallelepiped composite foam block is divided into two or more parts from the upper surface to the lower surface of the rectangular parallelepiped composite foam block, and each of the divided foam blocks is a quadrangular columnar foam block having a bottom surface with a substantially trapezoidal shape,
In each bottom surface of the quadrangular columnar foamed block, a pair of opposing base sides are approximately parallel to each other, and at least one end of a first base side of the pair of opposing base sides is located inwardly without protruding beyond both ends of a second base side, and a side edge is provided between the first base side and the second base side, the side edge expanding toward the second base side,
The rectangular parallelepiped composite foam block is constructed from two or more of the quadrangular columnar foam blocks by arranging the side surfaces including the expanding sides of the quadrangular columnar foam blocks so as to face each other,
The rectangular parallelepiped composite foam block is disposed in the excavation trench such that the column axis direction of the quadrangular columnar foam block coincides with the extension direction of the excavation trench.
A method for constructing lightweight earth fill structures.

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