Space structure and shielding structure

Abstract

To facilitate the construction and removal of a space structure.SOLUTION: A spatial structure 7 constituting a high evacuation space is constructed by placing a foundation block 1 provided with a plurality of frustum-shaped through-holes 11 penetrating from an upper surface 14 to a lower surface 15 on a surface of a leveled ground 6, and closing the through-holes 11 of the foundation block 1 with a lower surface 211 of a bottom slab 21 of a box culvert 2 placed on the upper surface 14 of the foundation block 1 in a state where crushed stones 4 are charged into each of the through-holes 11 of the foundation block 1.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a spatial structure that constitutes an emergency evacuation space and a shielding structure that is installed at the entrance and exit of the emergency evacuation space. [Background technology]

[0002] An emergency evacuation space of a certain size (for example, large enough to accommodate multiple vehicles) is constructed as a place to temporarily evacuate from danger (storm, tsunami, fire, war, etc.). Such an emergency evacuation space is constructed, for example, by a spatial structure constructed using box culverts (Patent Document 1). The emergency evacuation space (tsunami evacuation stage) disclosed in Patent Document 1 is constructed by a spatial structure in which a box culvert is placed on foundation concrete poured by digging a small hole in the ground, with the bottom slab of the box culvert buried in the ground and most of it exposed above ground (Patent Document 2

[0009] [Figure 1]). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-025253 Summary of the Invention [Problem to be solved by the invention]

[0004] The spatial structures that make up the emergency evacuation space are placed on top of a solid foundation, which stabilizes the box culvert's position and creates a highly safe emergency evacuation space. Conventionally, the solid foundation that stabilizes the box culvert's position was created by pouring concrete over crushed stone, which took time to form. However, when the period of use of the emergency evacuation space is limited, it is desirable that the spatial structure be easy to construct and remove. In this case, even if the box culvert, which is simply placed on the foundation, is easy to install and remove, if the foundation takes time to form and is difficult to remove, the spatial structure is not easy to construct and remove.

[0005] Since the safety of the emergency evacuation space can be further enhanced by installing a shielding structure in a position that hides the entrance and exit, it is preferable to construct a shielding structure together with the spatial structure. The shielding structure is constructed, for example, by placing an L-shaped retaining wall or an inverted T-shaped retaining wall on a solid foundation. Here, if the use period of the emergency evacuation space is limited and the construction and removal of the spatial structure is easy, it is desirable that the shielding structure also be easy to construct and remove. However, even if an L-shaped retaining wall or an inverted T-shaped retaining wall that is simply placed on the foundation is easy to install and remove, if the foundation takes time to form and is difficult to remove, the construction and removal of the shielding structure is not easy.

[0006] As such, the foundations of the spatial structures that make up emergency evacuation spaces and the shielding structures installed at the entrances and exits of emergency evacuation spaces take time to form and are difficult to remove, making their construction and removal difficult and making it difficult to use temporary emergency evacuation spaces.Therefore, in order to make it easier to construct and remove spatial structures and shielding structures when the period of use of highly safe emergency evacuation spaces that combine spatial structures and shielding structures is limited, we studied foundations that are strong enough to ensure the stability of culverts, L-shaped retaining walls, or inverted T-shaped retaining walls, but that take a short time to form and are easy to remove. [Means for solving the problem]

[0007] As a result of the study, we have developed a spatial structure that constitutes an emergency evacuation space, characterized in that foundation blocks with multiple frustum-shaped through holes that penetrate from the top to the bottom are placed on the surface of leveled ground, crushed stone is poured into each of the through holes in the foundation blocks, and the through holes in the foundation blocks are then blocked by the underside of the base plate of a box culvert placed on the top of the foundation blocks.The spatial structure of the present invention is based on foundation blocks and crushed stone.

[0008] The spatial structure of the present invention is constructed by forming a foundation on the surface of the ground that is continuous with the ground surface or on the surface of the ground that has been excavated from the ground surface. The spatial structure is basically constructed with one box culvert placed on one foundation block, but it may also be constructed with one box culvert placed on multiple foundation blocks, or multiple box culverts placed on one foundation block. A large emergency evacuation space is constructed by arranging multiple foundation blocks and box culverts in the direction in which the box culverts are connected. The box culvert may be constructed as an integral structure or as a separate structure.

[0009] The through-holes in the foundation blocks are frustum-shaped, with the cross-sectional area increasing from the top to the bottom, and examples include a truncated pyramid shape and a truncated cone shape. A truncated cone-shaped through-hole is basically structured so that the central axis (the line connecting the centers of gravity of horizontal cross-sections at different heights) coincides with a vertical line, but the central axis may intersect the vertical line or be twisted. Multiple through-holes of the same shape may be lined up, or a combination of different shapes may be lined up.

[0010] The foundation blocks should be rectangular in plan view, with either the length or width being the same as the bottom slab of the box culvert. The length of the bottom slab of the box culvert is the internal penetration direction, and the width of the bottom slab is the direction perpendicular to the internal penetration. The foundation blocks should be rectangular in plan view, with either the length or width being the same as the bottom slab of the box culvert, but preferably they should be rectangular in plan view, with both the length and width being the same as the bottom slab of the box culvert. In addition, the foundation blocks should have height adjusters that can adjust the amount of protrusion protruding toward the surface of the ground. For example, a total of four height adjusters should be installed in each of the recesses (counterbore) at symmetrical positions on the front and back and left and right of the foundation block.

[0011] The shielding structure of the present invention is a shielding structure to be installed at the entrance / exit of an emergency evacuation space, and is constructed by placing foundation blocks with a plurality of frustum-shaped through holes that penetrate from the top to the bottom on the surface of leveled ground, pouring crushed stone into each of the through holes in the foundation blocks, and then blocking the through holes in the foundation blocks with the underside of the base slab of an L-shaped or inverted T-shaped retaining wall placed on the top surface of the foundation blocks. The shielding structure of the present invention is constructed by forming the foundation on the surface of ground that has been leveled continuously with the ground surface or on ground that has been leveled by excavating the ground surface. The foundation blocks and crushed stone can be those of a spatial structure.

[0012] The foundation blocks should be rectangular in plan view, with either the length or width being the same as the base slab of the L-shaped or inverted T-shaped retaining wall. The length of the base slab of the L-shaped or inverted T-shaped retaining wall is perpendicular to the vertical wall, and the width of the base slab is parallel to the vertical wall. The foundation blocks should be rectangular in plan view, with either the length or width being the same as the base slab of the L-shaped or inverted T-shaped retaining wall, but preferably have both the length and width being the same as the base slab of the L-shaped or inverted T-shaped retaining wall. In addition, the foundation blocks should have height adjusters that can adjust the amount of protrusion protruding toward the surface of the ground. For example, a total of four height adjusters should be installed in recesses (counterbores) located symmetrically in the front and back and left and right of the foundation block. [Effects of the Invention]

[0013] The spatial structure and shielding structure of the present invention provide a highly safe emergency evacuation space that is easy to construct and remove. The foundation of the spatial structure and shielding structure is formed by filling the through-holes in the foundation blocks with the underside of the base plate of a box culvert, L-shaped retaining wall, or inverted T-shaped retaining wall, and then pressing crushed stone poured through the through-holes against the surface of the ground to fix the foundation blocks, which are not fixed to the ground, in place, forming a strong foundation. This ensures the stability of the box culvert, L-shaped retaining wall, or inverted T-shaped retaining wall. However, because the foundation blocks and crushed stone are not fixed to the ground, they are easy to remove.

[0014] If the foundation blocks have a rectangular shape in plan view with the same length or width as the base slab of the box culvert, L-shaped retaining wall, or inverted T-shaped retaining wall, it becomes easy to position the box culvert, L-shaped retaining wall, or inverted T-shaped retaining wall in the width direction relative to the foundation blocks, shortening the construction time required to build spatial structures and shielding structures.In addition, the sides of the foundation blocks, L-shaped retaining wall, or inverted T-shaped retaining wall are flush with the sides of the box culvert, so spatial structures or shielding structures can be built in close contact with adjacent box culverts, L-shaped retaining walls, or inverted T-shaped retaining walls.This allows the creation of emergency evacuation spaces with increased structural strength against external forces caused by danger, improving the safety of the emergency evacuation space.

[0015] When a height adjuster that can adjust the amount the foundation block protrudes is made to protrude toward the surface of the ground, the position of the foundation block can be adjusted horizontally by adjusting the amount of protrusion of the height adjuster, regardless of the unevenness of the surface of the ground on which the foundation block is placed, which increases the stability of the box culvert, L-shaped retaining wall, or inverted T-shaped retaining wall placed on the foundation block, and also makes it possible to align the height of the base slabs of lined-up box culverts, L-shaped retaining walls, or inverted T-shaped retaining walls. This increases the stability of the box culvert, L-shaped retaining wall, or inverted T-shaped retaining wall, and lined-up box culverts, L-shaped retaining walls, or inverted T-shaped retaining walls with the same base slab height increase the safety of emergency evacuation spaces. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a perspective view showing an example of a foundation block used in the foundation of the present invention. [Figure 2] 2 is a cross-sectional view taken along the line AA in FIG. [Figure 3] 1. FIG. [Figure 4] FIG. 1 is a perspective view showing a box culvert for constructing a spatial structure. [Figure 5] FIG. 1 is a perspective view showing an L-shaped retaining wall that constitutes a shielding structure. [Figure 6] FIG. 1 is a perspective view showing an emergency evacuation space constructed by combining the spatial structure and the shielding structure of this example. [Figure 7]FIG. 1 is a partial cross-sectional left side view showing construction procedure 1 of a spatial structure representing excavated ground. [Figure 8] This is a partial cross-sectional left side view showing construction procedure 2 of a spatial structure, in which foundation blocks are placed on the excavated ground and the posture of the foundation blocks is adjusted using height adjustment tools. [Figure 9] This is a partial cross-sectional left side view showing construction procedure 3 of a spatial structure, illustrating the process of pouring crushed stone through the through holes in the foundation blocks. [Figure 10] This is a partial cross-sectional left side view showing construction procedure 4 of a spatial structure, in which a box culvert is being placed on a foundation block after crushed stone has been poured into the through hole. [Figure 11] This is a partial cross-sectional left side view showing construction step 5 of the spatial structure, which has been completed by backfilling the gap between the ground and the box culvert. [Figure 12] This is a partially cross-sectional left side view showing construction step 5 of the shielding structure, which has been completed by backfilling the gap between the ground and the L-shaped retaining wall. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The foundation 5 used for the spatial structure 7 or shielding structure 8 of the present invention is formed on the surface of the ground 6 by excavating the ground surface 61 and leveling it using, for example, flat foundation blocks 1 and crushed stone 4 as shown in Figures 1 to 3 (see Figure 9 and others below). A box culvert 2, an L-shaped retaining wall 3, or an inverted T-shaped retaining wall (not shown) is placed on the upper surface 14 of the foundation 5 to construct the spatial structure 5 or shielding structure 8 (see Figure 6 below). In this example, the spatial structure 5 or shielding structure 8 is simply the box culvert 2 or the L-shaped retaining wall 3 placed on the foundation blocks 1, and is not connected to each other, so it can be easily removed.

[0018] As shown in Figures 1 to 3, the foundation block 1 in this example is a flat concrete block with parallel upper and lower surfaces 14 and 15 that are rectangular in plan view and have equal vertical and horizontal lengths for the base slabs 21, 31 of the box culvert 2 or L-shaped retaining wall 3. There are 24 through holes 11 in this example. Each through hole 11 has the same shape, a square truncated pyramid whose central axis coincides with a vertical line. The multiple through holes 11 are arranged at equal intervals and are evenly distributed across the entire area of ​​the foundation block 1 (see Figure 1).

[0019] In this example, the foundation block 1 has inserts 121 embedded in each of four truncated conical recesses (countersinks) 13 located near the corners of the top surface 14, and bolts 12 are screwed into each insert 121 from above, causing the bottom ends of the bolts 12 to protrude downward. The bolts 12 are height adjusters that can adjust the amount of protrusion, and when the foundation block 1 is placed on the surface of the ground 6 (see Figure 7 and subsequent figures), the bolt heads visible through the recesses 13 are turned to adjust the distance between the bolt ends and the surface of the ground 6. In this way, the foundation block 1 in this example is supported on the ground 6 by the four bolts 12 (see Figure 8).

[0020] As shown in Figure 4, the box culvert 2 in this example is a concrete block with a rectangular parallelepiped shape, consisting of a base slab 21 that is equal to the top surface 14 of the foundation block 1, and a top slab 23 that is the same size as the base slab 21, connected by left and right side slabs 22, 22, and can be a pre-made or dedicated product. In the box culvert 2 in this example, the entire lower surface 211 of the base slab 21 is in contact with the top surface 14 of the foundation block 1, sealing all of the through holes 11 in the foundation block 1. The bottom surface 211 and top surface 212 of the base slab 21 are flat and parallel to each other, and when the box culvert 2 is placed on the foundation block 1, the level of the top surface 212 follows the top surface 14 of the foundation block 1.

[0021] When the box culverts 2 of this example are lined up in a direction in which their internal spaces are connected, connectors 24 for connecting each other with connecting bolts (not shown) are provided on the front and rear end faces of the bottom slab 21 and both side slabs 22, 22 that surround the opening of the box culvert 2. The connectors 24 of this example are configured by fitting metal plates with oblique long holes into grooves cut out from the front and rear end faces of the bottom slab 21 and the side slabs 22, following the front and rear end faces, and the box culverts 2 are connected by passing connecting bolts through the long holes in the metal plates of the opposing connectors 24 of the lined up box culverts 2 and tightening them with connecting nuts.

[0022] As shown in Figure 5, the L-shaped retaining wall 3 in this example is a concrete block that is L-shaped in side view and has a vertical wall 32 that rises along one end face of the base slab 31 that is equal to the top face 14 of the foundation block 1, and is either a pre-made product or a dedicated product. In the L-shaped retaining wall 3 in this example, the entire lower face 311 of the base slab 31 is in contact with the top face 14 of the foundation block 1, and all of the through holes 11 in the foundation block 1 are blocked. The bottom face 311 and top face 312 of the base slab 31 are flat and parallel, and when the box culvert 2 is placed on the foundation block 1, the level of the top face 312 follows the top face 14 of the foundation block 1. A plurality of L-shaped retaining walls 3 are used, and as long as the base slab 31 is the same, L-shaped retaining walls and inverted T-shaped retaining walls of different shapes can be used singly or in combination.

[0023] In the L-shaped retaining wall 3 of this example, when the base slab 31 and the vertical wall 32 are lined up in a direction in which they are flush with each other, connectors 33 are provided on the left and right end faces of the base slab 31 and the vertical wall 32 to connect them to each other with connecting bolts (not shown). The connectors 33 of this example are configured by fitting metal plates with oblique long holes into grooves cut out from the left and right end faces of the base slab 31 and the vertical wall 32, following the front and rear end faces, and the L-shaped retaining walls 3 are connected by passing connecting bolts through the long holes in the metal plates of the connectors 24 facing each other on the lined up L-shaped retaining walls 3 and tightening them with connecting nuts.

[0024] An example of the construction procedure for the spatial structure 7 of this example will be described. The foundation 5 is formed on the leveled ground 6 at the bottom of the excavated depression without fixing the foundation blocks 1. First, as shown in Figure 7 as construction procedure 1, the construction site of the ground surface 61 is excavated, and the bottom of the depression is leveled to form the ground 6. The spatial structure 7 of the present invention can also be constructed with the ground surface 61 as the leveled ground 6. However, in order to avoid the occurrence of steps due to the bottom slab 21 of the box culvert 2 that forms the emergency evacuation space 71, it is preferable to excavate the ground surface 61 to a depth where the ground surface 61 and the upper surface 212 of the bottom slab 21 are flush with each other, and to make the bottom of the depression the leveled ground 6.

[0025] Next, as shown in Figure 8, construction procedure 2 involves placing one or more foundation blocks 1 in a row on the leveled ground 6. In this example, two foundation blocks 1 are placed in a row, and a box culvert 2 is placed on each of them. A metal plate 62 is placed on the ground 6 to support the lower ends of the bolts 12, which act as height adjustment devices. This allows the posture of the foundation block 1, which is supported by four bolts 12, to be adjusted by adjusting the amount of bolt 12 protruding, without having to sink each bolt 12 into the ground 6.

[0026] The ground 6 is leveled so that it is generally horizontal, but it does not have to be completely flat and horizontal; for example, it may be uneven. The foundation blocks 1 in this example adjust their posture by adjusting the protrusion of the bolts 12, which act as height adjusters, to absorb the effects of unevenness or tilt of the ground 6. A box culvert 2 is placed on each of the multiple foundation blocks 1, and by adjusting the posture of the foundation blocks 1, the posture of the bottom slabs 21 of the box culverts 2 placed on each foundation block 1 can be aligned, and the floor surface of the emergency evacuation space 71 formed can be made flat.

[0027] In this way, two foundation blocks 1 are placed on the ground 6, and with their top surfaces 14 aligned horizontally, and crushed stone 4 is poured into each of the through-holes 11, as shown in Figure 9, as construction procedure 3. Crushed stone 4 is poured into the gap between the bottom surface 15 of the foundation block 1 and the surface of the ground 6, and the excess is poured in until it spills out over the periphery of the foundation block 1. When the contoured surface of the crushed stone 4 accumulated in the through-hole 11 reaches the opening of the top surface 14 of the through-hole 11, the pouring is complete. Figure 9 shows the state in which crushed stone 4 has been poured into the foundation block 1 on the left side of the drawing, and about half of the foundation block 1 on the right side of the drawing has been poured.

[0028] Once the poured crushed stone 4 has reached the openings of the top surfaces 14 of all the through-holes 11, the next step in construction procedure 4 is to place the box culvert 2 on the foundation block 1 that has had the crushed stone 4 poured into it through the through-holes 11, as shown in Figure 10, and complete the foundation 5 consisting of the foundation block 1 and the crushed stone 4. The box culvert 2 can be placed on the foundation block 1 without any misalignment by aligning the length and width of the base slab 21 with the length and width of the foundation block 1, respectively.

[0029] In this example, the top surface 14 of the foundation block 1 and the bottom surface 211 of the bottom slab 21 of the box culvert 2 are both flat, so when the box culvert 2 is placed on the foundation block 1, the bottom surface 211 is in contact with the entire top surface 14 of the foundation block 1. This blocks all of the through holes 11 in the foundation block 1, and the crushed stone 4 protruding from the openings of the through holes 11 that appear on the top surface 14 is subjected to a downward force by the bottom surface 211 of the bottom slab 21 of the box culvert 2. In this way, the crushed stone 4 is filled into the through holes 11 so that it cannot move, and the crushed stone 4 pressed against the ground 6 prevents the foundation block 1 from moving.

[0030] As shown in Figure 11 as construction procedure 5, the box culverts 2 are placed on each foundation block 1, and then the excavated depressions and gaps are filled with backfill 63 to prevent displacement. In this way, the spatial structure 7 is constructed using box culverts 2 that are prevented from dislocation by the backfill 63, even though they are simply placed on the foundation blocks 1. In this example, the spatial structure 7 is constructed with the top surface 212 of the bottom slab 21 of the box culvert 2 continuing to the ground surface 61, and forms an emergency evacuation space 71 that connects two internal spaces surrounded by the side slabs 22 and top slab 23.

[0031] The spatial structure 2 in this example constitutes an emergency evacuation space 71 that is surrounded by side slabs 22 and a top slab 23, except for the opening of the box culvert 2, which serves as the entrance and exit to the emergency evacuation space 71. To increase the safety inside such an emergency evacuation space 71, a shielding structure 8 is constructed in which L-shaped retaining walls 3 are lined up with vertical walls 33 perpendicular to the opening of the box culvert 2, as shown in Figure 6 (connectors 24, 33 are not shown). The shielding structure 8 in this example is constructed at a position away from the opening of the box culvert 2, taking into consideration the entry and exit of vehicles into and out of the emergency evacuation space 71, but it may also be constructed in a position very close to the opening of the box culvert 2, for example, if only the entry and exit of people is considered.

[0032] As shown in Figure 12, the shielding structure 8 of this example has a structure in which an L-shaped retaining wall 3 is placed on a foundation block 1 instead of a box culvert 2. The foundation 5 is composed of the foundation block 1 placed on leveled ground 6 at the bottom of an excavated depression and crushed stone 4 poured into through holes 11 in the foundation block 1, and the crushed stone 4 is blocked by the underside 311 of the bottom slab 31 of the L-shaped retaining wall 3 placed on the foundation block 1. The foundation block 1 is the same as the foundation block 1 of the spatial structure 7, which is equipped with a height adjustment device, and its posture can be adjusted using a bolt 12 that presses its lower end against a metal plate 62 placed on the ground 6 as the height adjustment device.

[0033] The L-shaped retaining wall 3 can be placed without misalignment on the foundation block 1 by aligning the length and width of the base slab 21 with the length and width of the foundation block 1. As described above, in the shielding structure 8 of this example, the L-shaped retaining wall 3 is placed on the foundation block 1 with the vertical wall 32 facing away from the opening of the box culvert 2 in order to open the entrance and exit of the emergency evacuation space 71 wide to allow for vehicle entry and exit. However, even when constructing the shielding structure 8 in the same position, it is possible to limit the entry and exit of people and narrow the entrance and exit of the emergency evacuation space 71 by, for example, placing the L-shaped retaining wall 3 on the foundation block 1 with the vertical wall 32 facing closer to the opening of the box culvert 2.

[0034] The L-shaped retaining wall 3 placed on the foundation block 1 has the underside 311 of the base slab 31 in contact with the entire top surface 14 of the foundation block 1, blocking all of the through holes 11 in the foundation block 1 and applying a downward force to the crushed stone 4 protruding from the openings of the through holes 11 that appear on the top surface 14. In this way, the crushed stone 4 is filled into the through holes 11 so that it cannot move, and the crushed stone 4 pressed against the ground 6 prevents the foundation block 1 from moving. In this way, the function of preventing the foundation 5 composed of the foundation block 1 and the crushed stone 4 from moving is the same for the spatial structure 7 and the shielding structure 8.

[0035] After the L-shaped retaining walls 3 are placed on each foundation block 1, the excavated depressions and gaps are filled with backfill 63 to prevent displacement. In this way, like the spatial structure 7, the shielding structure 8 is constructed using L-shaped retaining walls 3 that are prevented from dislocating by the backfill 63, even though they are simply placed on the foundation blocks 1. The shielding structure of this example is configured so that the upper surface 312 of the base slab 31 of the L-shaped retaining wall 3 is continuous with the ground surface 61, and only the vertical wall 32 stands. Although illustration and explanation are omitted, the shielding structure 8 can be constructed using an inverted T-shaped retaining wall instead of the L-shaped retaining wall 3. In a shielding structure 8 using an inverted T-shaped retaining wall, the vertical wall remains in approximately the same position even if the orientation is changed. [Explanation of symbols]

[0036] 1 foundation block 11 Square pyramidal truncated through hole 12 Height adjustment bolt 121 Insert 13 Conical recess 14 Top side 15 Bottom side 2 Box culverts 21 bottom plate 211 Bottom surface 22 side version 23 Heaven version 24 Connector 3 L-shaped retaining wall 31 Bottom plate 311 Bottom surface 32 Vertical Wall 33 Connector 4. Crushed Stone 5 Basics 6 Excavated and leveled ground 61 Ground surface 62 Metal plate 63 Backfill 7 Spatial structures 71 Emergency evacuation space 8 Shielding structures

Claims

1. A spatial structure that constitutes an emergency evacuation space, A foundation block with multiple truncated cone-shaped through-holes penetrating from the top to the bottom is placed on the surface of the leveled ground, and crushed stone is poured into each of the through-holes of the foundation block. The through-holes of the foundation block are then blocked by the underside of the bottom plate of a box culvert placed on the top of the foundation block. A spatial structure characterized by:

2. The foundation block is rectangular in plan view, with the same length or width as the bottom plate of the box culvert. The spatial structure according to claim 1.

3. The foundation blocks have height adjusters that can adjust the amount of protrusion, projecting toward the ground surface.

3. The spatial structure according to claim 1 or 2.

4. A shielding structure installed at the entrance and exit of an emergency evacuation space, A foundation block with multiple truncated cone-shaped through-holes penetrating from the top to the bottom is placed on the surface of the leveled ground, and crushed stone is poured into each of the through-holes of the foundation block. The through-holes of the foundation block are then blocked by the underside of the base plate of an L-shaped or inverted T-shaped retaining wall placed on the top of the foundation block. A shielding structure characterized by:

5. The foundation block is a square block in plan view with the same length or width as the base plate of the L-shaped or inverted T-shaped retaining wall. The shielding structure according to claim 4.

6. The foundation blocks have height adjusters that can adjust the amount of protrusion, projecting toward the ground surface.

6. A shielding structure according to claim 4 or 5.

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