JP7645733B2 - Earth retaining structure - Google Patents

Description

The present invention relates to a retaining structure constructed on the ground, and in particular to a retaining structure constructed by connecting the flanges of multiple retaining members with connecting fittings.

Conventionally, civil engineering structures such as shafts for constructing foundations for structures, underground collection wells, and sloped retaining walls are constructed with retaining structures that are made by connecting retaining members such as earth retaining members to form a ring-shaped or horseshoe-shaped (U-shaped) wall.

This type of earth retaining structure has the advantage that each of the earth retaining components is lightweight and can be easily constructed by hand, even in mountainous areas where large heavy machinery cannot be used. For example, when constructing a shaft with a small inner diameter, a single worker can enter the shaft and connect the earth retaining components.

Retaining members can be connected together with bolts and nuts, but when a single worker connects retaining members, it is difficult and time-consuming to pass the bolt through the connecting hole formed in the flange of the retaining member. Therefore, by connecting the flanges of the retaining members together using a connecting fitting that has an insertion part that is inserted into the connecting hole and a clamping part that clamps the flange, the worker can support the retaining member with one hand while performing the connecting work.

The connecting fitting connects the retaining members by overlapping and clamping the flanges of the retaining members with the clamping part. The tip of the insertion part of the connecting fitting is bent into an L-shape so that the tip abuts against the periphery of the connection hole formed in the flanges of the retaining members. This makes the flanges of the retaining members supported at two points, the tip of the insertion part and the clamping part, making the connection strong (see, for example, Patent Document 1).

JP 2020-2634 A

Because an earth-retaining structure is constructed by combining multiple earth-retaining members, the connections between the multiple earth-retaining members are prone to displacement when subjected to earth pressure from the ground. In particular, as in Patent Document 1, an earth-retaining structure uses connecting fittings to connect multiple earth-retaining members, making it easier to connect the members while ensuring the connecting force between them. However, when multiple earth-retaining members are connected together using connecting fittings, there is an issue that the strength and rigidity of the earth-retaining structure varies at some of the connecting parts because the connecting fittings have a directional property.

The present invention aims to solve the above problems and provide an earth retaining structure that reduces the variation in strength and rigidity of each connecting part.

The earth retaining structure according to the present invention is constructed by connecting a plurality of earth retaining members, the ends of which are shifted in a first direction, in a second direction perpendicular to the first direction using a plurality of connecting members, and is an earth retaining structure in which the earth retaining members hold back soil in the ground and form a space, and each of the plurality of earth retaining members has a main body arranged along the ground and a flange portion protruding from the edge of the main body in the second direction toward the space, and the flange portion has a connecting hole formed through the thickness direction of the flange portion, and the plurality of connecting members include a plurality of connecting fittings, and the plurality of connecting fittings are attached to a connecting portion formed by overlapping the flange portions of the plurality of adjacent earth retaining members. The connecting hardware includes a connecting hardware body, an insertion portion formed by bending one end of a member constituting the connecting hardware body toward one side of the connecting hardware body, and a clamping portion formed by bending the other end of the member constituting the connecting hardware body toward the one side in a U-shape, the insertion portion is inserted into the connecting hole formed in each of the plurality of adjacent earth retaining members, the clamping portion clamps the flange portions of the plurality of adjacent earth retaining members in an overlapping state, and the plurality of connecting hardware includes a first connecting hardware and a second connecting hardware that is installed in the connecting portion with the one side facing in a different direction from the first connecting hardware.

According to the present invention, the retaining structure can partially change the direction of the connecting fittings, so that even if the retaining members are displaced by external forces such as earth pressure, the connecting fittings can maintain the connection between the retaining members. This allows the retaining structure to reduce variation in the strength and rigidity of each connection between the retaining members.

1 is an oblique view of an earth retaining structure 100 according to embodiment 1. FIG. 1 is a plan view and a cross-sectional structural diagram of an earth retaining structure 100 according to embodiment 1. FIG. This is an enlarged view of the axial connecting portion 11 and the area around the connecting portion 12 of the earth retaining member 10 of the earth retaining structure 100 of embodiment 1. A cross-sectional view of an earth retaining member 10 according to embodiment 1. A cross-sectional view of an earth retaining member 10 according to embodiment 1. 1 is an oblique view of a connecting fitting 20 that connects the earth retaining members 10 of the earth retaining structure 100 of embodiment 1. FIG. FIG. 7 is a top view of the connecting fitting 20 of FIG. 6 . FIG. 7 is a side view of the connecting fitting 20 of FIG. 6 . FIG. 7 is a bottom view of the connecting fitting 20 of FIG. 6 . 1 is an oblique view of a connecting fitting 20 attached to an earth retaining structure 100 according to embodiment 1. FIG. 1 is an oblique view of a connecting fitting 20 attached to an earth retaining structure 100 according to embodiment 1. FIG. This is a cross-sectional view showing the state in which the first retaining member 10a of the retaining structure 1100 which is a comparative example of the retaining structure 100 of embodiment 1 is subjected to earth pressure. A cross-sectional view showing the state in which the first retaining member 10a of the retaining structure 100 of embodiment 1 is subjected to earth pressure. 1 is a perspective view of a connecting fitting 120 which is a modified example of the connecting fitting 20 according to the first embodiment. FIG. 1 is a cross-sectional view of a portion of an earth retaining structure 200 according to embodiment 2. An oblique view of an earth retaining structure 100 relating to embodiment 3. 17 is an enlarged oblique view of the area around the axial connection portion 11 of the earth retaining structure 100 of FIG. 16. A cross-sectional view showing the state in which the earth retaining member 10 of the earth retaining structure 100 of embodiment 3 is displaced by earth pressure. A schematic diagram illustrating an example of the arrangement of connecting fittings 20 of an earth retaining structure 400 relating to embodiment 4.

The following describes the retaining structure 100 and retaining member 10 according to the embodiment with reference to the drawings. Note that in the following drawings, including FIG. 1, the relative dimensional relationships and shapes of the components may differ from the actual ones. In the following drawings, the same reference numerals are used to denote the same or equivalent items, and this applies throughout the entire specification. In addition, to facilitate understanding, terms indicating directions (e.g., up, down, left, right, front, back, front and back, etc.) are used as appropriate, but these notations are for the convenience of explanation and do not limit the arrangement, direction or orientation of devices, instruments, parts, etc.

Embodiment 1.
[Earth retaining structure 100]
FIG. 1 is a perspective view of the retaining structure 100 according to the first embodiment. FIG. 2 is a plan view and a cross-sectional structural view of the retaining structure 100 according to the first embodiment. FIG. 3 is an enlarged view of the periphery of the axial connecting portion 11 and the connecting portion 12 of the retaining member 10 of the retaining structure 100 according to the first embodiment. FIG. 3 is an enlarged view of the part B in FIG. 2(b). The retaining structure 100 will be described with reference to FIGS. 1 to 3. The retaining structure 100 is, for example, a civil engineering structure such as a vertical shaft for constructing the foundation of a structure or a drainage well constructed in the ground, and is constructed inside a vertical hole formed by excavating the ground. In the following description, the outside of the retaining structure 100 is called the natural ground 92, and the inside is called the space portion 93. In the first embodiment, the retaining structure 100 is formed in a circular tube shape, but is not limited to a circular tube shape. The retaining structure 100 can be formed in an oval, elliptical, rectangular, oval, or horseshoe shape in a plan view, and is not limited to a tube shape. 2 indicates the radial direction of the earth retaining structure 100, the θ direction is the circumferential direction, and the z direction is the height direction. The θ direction coincides with the longitudinal direction of the earth retaining member 10 and is referred to as the first direction. The z direction coincides with the width direction of the earth retaining member 10 and is referred to as the second direction. In the first embodiment, the z direction coincides with the direction of gravity, but is not limited thereto and may be inclined toward the direction of gravity.

The retaining structure 100 according to the first embodiment has a structure in which a plurality of retaining members 10 are connected by a plurality of connecting members to form annular bodies 50, and the annular bodies 50 are connected to each other in the axial direction by a plurality of connecting members. The retaining structure 100 shown in Figures 1 and 2 has a structure in which annular bodies 50A and 50B are stacked alternately in six stages in the z direction.

[Annular body 50]
Each annular body 50 constituting the earth retaining structure 100 is formed by connecting a plurality of earth retaining members 10 in the θ direction, and is formed by connecting the longitudinal ends of the earth retaining members 10 to each other. The earth retaining members 10 include a main body 14 (see FIG. 4 and FIG. 5) corrugated in the width direction, i.e., in the z direction, and flat connecting plates 19 at both ends of the main body 14 in the longitudinal direction, i.e., in the θ direction. The connecting plates 19 are welded to the longitudinal end faces of the main body 14. In the annular body 50, the connecting plates 19 of adjacent earth retaining members 10 are joined to each other by connecting fittings 20g or fastening members 40 to form an axial connecting portion 11. The axial connecting portion 11 is a portion that connects the connecting plates 19 extending in the axial direction to each other, and is a connecting portion that extends in the z direction. Note that three connecting fittings 20g are attached to the axial connecting portion 11 shown in FIG. 3, but the number of connecting fittings 20g attached can be appropriately changed depending on the shape of the earth retaining members 10. For example, in the case of the earth retaining member 10 shown in FIG. 4 described later, four connecting fittings 20 g are attached to the axial connecting portion 11 .

The annular bodies 50 formed by the soil retaining members 10 are joined together by connecting fittings 20 at the ends of the soil retaining members 10 in the z direction. As shown in FIG. 2(b), the soil retaining members 10 of the upper annular body 50A and the soil retaining members 10 of the lower annular body 50B are joined with both ends in the longitudinal direction (θ direction) shifted from each other. In the first embodiment, the soil retaining members 10 located above and the soil retaining members 10 located below are connected with a shift of half the longitudinal length. This allows the soil retaining structure 100 to suppress variations in strength and rigidity at each position in the θ direction. However, the soil retaining members 10 located above and below are not limited to being connected with a half shift in the longitudinal direction. For example, the soil retaining members 10 may be connected with at least one or more connecting holes 13a formed in the flange portion 13 of the soil retaining members 10 shifted in the longitudinal direction.

[Earth retaining member 10]
4 and 5 are cross-sectional views of the retaining member 10 according to the first embodiment. 4 and 5 show a cross section perpendicular to the longitudinal direction of the retaining member 10, and show an example of a cross section including the C-C portion of the retaining structure 100 shown in FIG. 3. The body 14 of the retaining member 10 shown in FIG. 4 has a sine curve-like waveform in a cross section perpendicular to the longitudinal direction. Also, the body 14 of the retaining member 10 shown in FIG. 5 has a rectangular wave shape with rounded corners, and parallel surfaces are formed on the outside and inside of the retaining structure 100.

The retaining members 10 shown in Figures 4 and 5 have different cross-sectional shapes and different corrugations of the main body 14, but flanges 13 are formed at both ends in the z direction, making them connectable to each other in the z direction. The flanges 13 have connecting holes 13a for connecting fittings 20 or fastening members 40. Multiple connecting holes 13a are formed in the flanges 13, and are spaced equally apart in the θ direction.

The body 14 of the retaining member 10 shown in FIG. 4 has a sine curve-like waveform, and can withstand the load caused by earth pressure from the ground. Because the body 14 has a wavy shape, it has higher strength and rigidity against the load applied in the r direction than if it were formed with a simple flat cross-sectional shape.

The trapezoidally corrugated body 14 of the retaining member 10 shown in FIG. 5 includes an inner flange portion 16 that protrudes inward from the annular body 50 in the cross section of FIG. 5, and outer flange portions 17 and 18 that protrude outward from the annular body 50. The inner flange portion 16 and the outer flange portions 17 and 18 are formed substantially parallel to each other. The inner flange portion 16 and the outer flange portions 17 and 18 are connected by a web portion 15. The web portion 15 has a surface that extends in the r direction in the cross section of FIG. 5 and is slightly inclined with respect to the r direction. The inclination direction of the web portion 15 is such that, when the body 14 is viewed from the central axis C, the open end of the valley portion of the corrugated shape is wide and the valley bottom is narrow. By being configured in this way, the body 14 is easy to release from the mold when performing plastic processing for corrugation, making it easy to manufacture.

In addition, the web portion 15 is formed at an angle close to parallel to the r axis, so that the widths of the inner flange portion 16 and the outer flange portions 17 and 18 are wide. As a result, the retaining member 10 has a high rigidity when a bending moment is applied in the r direction. For example, the retaining member 10 shown in FIG. 5 has a larger dimension in the r direction than the retaining member 10 shown in FIG. 4, and has a high rigidity against a load applied in the r direction. When the retaining member 10 of the retaining structure 100 in FIG. 1 is loaded in the surface direction, that is, in the r direction, a bending moment is applied to the retaining member 10 in the r direction. At this time, the section modulus of the retaining member 10 about the bending neutral axis N is larger when the widths of the inner flange portion 16, the outer flange portion 17, and 18 farther from the neutral axis N are wider. Therefore, by forming the web portion 15 at an angle close to parallel to the r axis, the width dimensions in the z direction of the inner flange portion 16, the outer flange portion 17, and 18 are widened, and the retaining member 10 has a high strength and rigidity against a bending load in the r direction. Specifically, the web portion 15 is set at an angle of 0° to 20°, and more preferably at an angle of 0° to 3°, relative to the direction perpendicular to the inner flange portion 16 or the outer flange portions 17 and 18.

In FIG. 5, the inner flange portion 16 and the outer flange portions 17 and 18 are formed with the same plate thickness as the web portion 15, but the plate thickness may be made thicker than that of the web portion 15. By configuring them in this way, the cross-sectional area of the inner flange portion 16 and the outer flange portions 17 and 18 that are far from the neutral axis N becomes larger, and the section modulus of the soil retaining member 10 can be further increased.

The retaining member 10 shown in Figures 4 and 5 has flanges 13 formed at both ends in the z direction. The flanges 13 are formed perpendicular to the z direction, and have connecting holes 13a in their flat portions. The flanges 13 are parallel to the r and θ directions, and have a surface to which the connecting fitting 20 can be attached. In particular, the tip 13b of the flanges 13 has a flat surface to which the clamping portion 23 (see Figures 6 to 9) of the connecting fitting 20 can fit.

[Connecting fitting 20]
FIG. 6 is a perspective view of the connecting fitting 20 that connects the retaining members 10 of the retaining structure 100 according to the first embodiment. FIG. 7 is a top view of the connecting fitting 20 of FIG. 6. FIG. 8 is a side view of the connecting fitting 20 of FIG. 6. FIG. 9 is a bottom view of the connecting fitting 20 of FIG. 6. The plane formed by the x-direction and y-direction shown in FIG. 6 to FIG. 9 is a plane along the connecting fitting body 22 of the connecting fitting 20, and the z-direction indicates a direction perpendicular to the x-direction and the y-direction. The x-direction coincides with the width direction of the clamping portion 23, and approximately coincides with the θ-direction when the connecting fitting 20 is attached to the flange portion 13. In the first embodiment, the connecting fitting 20 is a fitting formed by bending a metal plate, and is one of the connecting members that connect the retaining members 10. The connecting fitting 20 comprises a connecting fitting main body 22 having a convex portion 26 formed by embossing, an insertion portion 25 bent from one end of the connecting fitting main body 22 in the y direction in the opposite direction to the z direction, and a clamping portion 23 bent from the other end of the connecting fitting main body 22 in the y direction in the opposite direction to the z direction.

The connecting fitting 20 connects two retaining members 10 by inserting the insertion portion 25 into the connecting hole 13a formed in the flange portion 13 of the retaining member 10 and clamping the tip portion 13b of the flange portion 13 with the clamping portion 23. The connecting fitting 20 can connect the retaining members 10 by fitting it into the flange portion 13, which improves the efficiency of the connecting work compared to connections using bolts and nuts.

As shown in Figures 7 and 9, the edge 22c of the clamping end 22a where the clamping portion 23 of the connecting fitting body 22 is formed is formed parallel to the x-axis. The connecting fitting body 22 extends at an angle to the y-direction. The y-direction edge 22d of the connecting fitting body 22 is connected to the insertion portion 25 that extends in the opposite direction to the z-direction. The edge 22d to which the insertion portion 25 is connected is inclined to the x-axis.

The insertion portion 25 extends in the z direction from the edge 22d of the connecting metal body 22, and is bent at its tip into an L shape to form the tip portion 21. The tip portion 21 has a plate surface 21b extending along the y direction. The plate surface 21b of the tip portion 21 is formed approximately parallel to the plate surface of the connecting metal body 22 at a position shifted in the z direction from the connecting metal body 22. Alternatively, the plate surface 21b of the tip portion 21 may not be parallel to the plate surface of the connecting metal body 22, and may be inclined so that the tip 21a faces in the z direction. By configuring it in this way, the connecting metal body 22 is arranged on one side of the flange portions 13 of the two earth retaining members 10 to be connected, and the tip portion 21 is arranged on the other side, and the two flange portions 13 can be held between the tip portion 21 and the connecting metal body 22.

As shown in FIG. 7, the insertion end 22b where the insertion portion 25 of the connecting fitting body 22 is formed is narrower than the clamping end 22a where the clamping portion 23 is formed, and is formed to a width that can be inserted into the connecting hole 13a of the flange portion 13. In other words, the tip portion 21 can be freely inserted into the connecting hole 13a of the flange portions 13 of the two retaining members 10. In addition, the insertion end 22b is embossed to form a protrusion 26, which improves its rigidity.

On the other hand, the clamping side end 22a where the clamping portion 23 is formed is formed with a wide width so that the clamping portion 23 can clamp and hold the flange portions 13 of the two retaining members 10.

[Attachment state of the connecting fitting 20]
Figures 10 and 11 are perspective views of connecting fittings 20 attached to the earth-retaining structure 100 according to embodiment 1. Figure 10 is a perspective view of first connecting fittings 20a, 20b, 20e, and 20f of the earth-retaining structure 100 shown in Figure 3. Figure 11 is a perspective view of connecting fittings 20c and 20d of the earth-retaining structure 100 shown in Figure 3. In embodiment 1, the connecting fittings 20 installed at the connection parts 12 with the annular bodies 50A and 50B of the earth-retaining structure 100 are not all attached facing the same direction, but are partially attached facing in the opposite direction to the z direction shown in Figures 6 to 9.

Specifically, the first connecting fittings 20a, 20b, 20e, and 20f shown in Fig. 3 are arranged in a state in which the insertion portion 25 and the clamping portion 23 extend from the connecting fitting body 22 in the z direction in the opposite direction, i.e., in the state shown in Fig. 10. The connecting fittings 20c and 20d shown in Fig. 3 are arranged in a state in which the insertion portion 25 and the clamping portion 23 extend from the connecting fitting body 22 in the z direction, i.e., in the state shown in Fig. 11.

10 and 11, the connecting fitting 20 has the tip 21 and insertion portion 25 inserted into the connecting hole 13a of the flange portion 13, and the clamping portion 23 clamps the flange portion 13 of the two retaining members 10 to connect the retaining members 10 together. With the tip 21 and insertion portion 25 inserted into the connecting hole 13a, the connecting fitting 20 is rotated around the connecting hole 13a to insert the flange portion 13 between the clamping portion 23 and the connecting fitting body 22. The opening width between the abutting portion 23b of the clamping portion 23 and the connecting fitting body 22 is formed narrower than the thickness dimension of the tip portions 13b of the two flange portions 13, and the abutting portion 23b of the clamping portion 23 and the connecting fitting body 22 hold the two flange portions 13 in pressure contact in the z direction.

Returning to FIG. 3, the arrangement of the multiple connecting fittings 20 attached to the earth-retaining structure 100 according to embodiment 1 will be described. The multiple earth-retaining members 10 constituting the earth-retaining structure 100 are connected to each other in the z and θ directions by connecting fittings 20. The z-direction connecting portion 12 connecting the annular body 50A and the annular body 50B is connected by multiple connecting fittings 20. Some of the multiple connecting fittings 20 at the connecting portion 12 are attached facing in the opposite direction. Note that the connection in the θ direction between each of the annular bodies 50A and 50B is also performed by connecting fittings 20.

The earth retaining members 10 constituting the annular body 50A and the earth retaining members 10 constituting the annular body 50B are arranged at positions where the connecting plates 19 arranged at the longitudinal ends are offset in the θ direction. The axial connecting parts 11 formed on the annular body 50A and the axial connecting parts 11 formed on the annular body 50B are arranged at positions where they are offset from each other in the θ direction. In other words, as shown in FIG. 3, the axial connecting parts 11 of the annular body 50A and the intermediate parts in the θ direction of the earth retaining members 10c and 10d of the annular body 50B are aligned in the z direction.

When we look at the periphery of the axial connection portion 11 of the first retaining members 10a and 10b of the annular body 50A, the first retaining members 10a and 10b are connected to the second retaining member 10c in the z direction, and to the third retaining member 10d on the opposite side in the z direction. The flange portion 13 of the first retaining member 10a and the flange portion 13 of the second retaining member 10c are overlapped so that the connection holes 13a are aligned to form the first connection portion 12a. The flange portion 13 of the first retaining member 10a and the flange portion 13 of the third retaining member 10d are overlapped so that the connection holes 13a are aligned to form the second connection portion 12b.

The first connecting portion 12a and the second connecting portion 12b are connected by inserting the connecting fittings 20 into the overlapping connecting holes 13a and by the clamping portion 23 clamping and holding the two flange portions 13.

The connecting fittings 20a, 20b, and 20e attached to the first connecting portion 12a shown in FIG. 3 are attached to the flange portion 13 in a position in which the clamping portion 23 and the insertion portion 25 extend in the opposite direction z from the connecting fitting body 22 as shown in FIG. 10. These connecting fittings 20 are referred to as first connecting fittings.

Of the connecting fittings 20 attached to the second connecting portion 12b, the connecting fitting 20c located at the end of the first retaining member 10a in the θ direction is attached facing in the opposite direction to the first connecting fitting 20a as shown in FIG. 11. In other words, the connecting fitting 20c is attached to the flange portion 13 with the clamping portion 23 and the insertion portion 25 extending in the z direction from the connecting fitting main body 22. These connecting fittings 20 are referred to as second connecting fittings.

These connecting fittings 20 are arranged in the same manner in the first retaining member 10b, which is arranged adjacent to the first retaining member 10a. In other words, at least the two connecting fittings 20 arranged at the ends of the flange portions 13 of the first retaining members 10a and 10b in the θ direction are arranged so that one side 22e (see FIG. 8) facing the direction in which the insertion portion 25 and the clamping portion 23 extend from the connecting fitting body 22 faces each other. In other words, the first connecting fitting 20a and the second connecting fitting 20c are arranged opposite each other at the ends of the flange portions 13 of the first retaining members 10a and 10b in the θ direction.

In FIG. 3, attention is focused on the periphery of the axial connecting portion 11 of the first retaining members 10a and 10b, but all of the retaining members 10 constituting the retaining structure 100 have an axial connecting portion 11. In the retaining structure 100, the two connecting fittings 20 arranged closest to the axial connecting portion 11 of the retaining members 10 are attached so that one side 22e faces each other.

In other words, in the second connecting portion 12b of the first retaining member 10a, the second connecting fitting 20c is positioned closer to the end of the first retaining member than the first connecting fitting 20f, that is, closer to the axial connecting portion 11.

[Function of the connecting fitting 20]
Fig. 12 is a cross-sectional view showing a state in which the first earth-retaining member 10a of the earth-retaining structure 1100 according to a comparative example of the earth-retaining structure 100 according to the first embodiment is subjected to earth pressure. Fig. 12 is a schematic diagram illustrating the state of the connecting fitting 20 closest to the axial connecting portion 11 of the first earth-retaining member 10a of the earth-retaining structure 1100. The earth-retaining structure 1100 according to the comparative example connects multiple earth-retaining members 10 using connecting fittings 20, similar to the earth-retaining structure 100 according to the first embodiment. However, in the earth-retaining structure 1100 according to the comparative example, all of the connecting fittings 20 are attached facing in the same direction.

As shown in FIG. 12(a), when the retaining structure 1100 is in its normal state, the connecting fittings 20 located above and below in the z-direction hold the two flanges 13 in an overlapping state by the tip 21, the connecting fitting body 22, and the clamping portion 23, connecting multiple retaining members 10.

Figure 12 (b) shows a state in which the retaining structure 1100 is subjected to a load due to earth pressure or the like from the ground side on the outside. Since the retaining structure 1100 is subjected to earth pressure on its entire outer periphery, the retaining members 10 positioned side by side in the z direction will not generally shift in the r direction. However, if a large load is locally applied to the outer periphery of the retaining structure 1100, the θ-direction end of the retaining member 10 will shift in the r direction by the amount of the clearance between the insertion portion 25 of the connecting fitting 20 and the connecting hole 13a.

The connecting fitting 20 located on the upper side of FIG. 12(b) maintains the abutment portion 23b of the clamping portion 23 in contact with the back surface 13c of the flange portion 13 when the first retaining member 10a is displaced in the opposite direction r. On the other hand, the connecting fitting 20 located on the lower side of FIG. 12(b) shifts so that the back surface 13c of the flange portion 13 disengages from the abutment portion 23b of the clamping portion 23, and the abutment portion 23b of the clamping portion 23 can no longer apply a load to the flange portion 13. Therefore, the connecting fitting 20 on the lower side of FIG. 12(b) is easily disengaged from the flange portion 13, and the connection between the retaining members 10 is weak.

Figure 13 is a cross-sectional view showing the state in which the first retaining member 10a of the retaining structure 100 according to the first embodiment is subjected to earth pressure. Unlike the retaining structure 1100 according to the comparative example shown in Figure 12, the retaining structure 100 has the lower connecting fitting 20 attached in the opposite direction. At this time, even if the retaining member 10a is displaced in the opposite direction r, the abutting portion 23b of the clamping portion 23 remains in abutment with the back surface 13c of the flange portion 13. Therefore, the connecting fitting 20 can continue to apply a load in the direction in which the two flange portions 13 are pressed together. In Figure 13, the connecting fittings 20 located at the top and bottom are both configured to suppress a decrease in the connecting force even when a load is applied to the retaining structure 100, and the strength and rigidity of the retaining structure 100 can be suppressed from decreasing, and the variation in strength and rigidity in the circumferential direction of the retaining structure 100 can be suppressed.

In general, in an earth retaining structure 100 formed by connecting multiple earth retaining members 10, the earth retaining members 10 are prone to displacement at the axial connecting portion 11, but by changing the directionality of the connecting fitting 20 closest to the θ-direction end of the earth retaining member 10 as described above, it is possible to reduce the variation in strength and rigidity of each part of the earth retaining structure 100. Specifically, the connecting fitting 20 closest to the axial connecting portion 11 is positioned so that the directions in which the insertion portion 25 and the clamping portion 23 extend are opposed to each other.

[Modification]
In the above description, the embodiment has been described in which the directionality of only the connecting fitting 20 closest to the axial connecting portion 11 in the earth-retaining structure 100 is changed, but the connecting fitting 20 that changes the directionality may be provided not only with one connecting fitting 20 closest to the axial connecting portion 11 but also with two or more connecting fittings 20. In other words, the number of connecting fittings 20 that change the directionality of the connecting fitting 20d shown in FIG. 3 can be appropriately changed depending on the amount of displacement of the earth-retaining member 10 or the earth pressure that the earth-retaining structure 100 is subjected to.

Figure 14 is a perspective view of a connecting fitting 120, which is a modified example of the connecting fitting 20 according to the first embodiment. In the modified connecting fitting 120, the insertion portion 25 is not inclined relative to the clamping portion 23. Therefore, the connecting fitting 120 connects multiple earth retaining members 10 by fitting the clamping portion 23 into the flange portion 13 while inserting the insertion portion 25 into the connecting hole 13a. In the earth retaining structure 100 connected by the connecting fitting 120 configured in this manner, as with the connecting fitting 20 according to the first embodiment, by changing the mounting direction near the axial connecting portion 11a, the earth retaining structure 100 is less likely to come off the flange portion 13, and the variation in strength and rigidity in the circumferential direction of the earth retaining structure 100 can be suppressed.

The connecting fittings used in the retaining structure 100 according to the first embodiment are not limited to those formed by bending a metal plate, such as the connecting fitting 20 shown in FIG. 6 or the connecting fitting 120 shown in FIG. 14. The connecting fittings may be of other shapes as long as they have an insertion portion 25 extending from the connecting fitting main body 22 toward one side 22e and a clamping portion 23.

In addition, in the earth retaining structure 100 according to the first embodiment, one or more connecting fittings 20 at the very end of the first earth retaining member 10a are arranged to face each other, but even in other configurations, the effect of the connecting fittings 20 being less likely to come off can be expected as shown in Fig. 13. In other words, the earth retaining structure 100 may be configured to include a first connecting fitting 20b and a second connecting fitting 20d that is installed in the connecting portion 12a with one side 22e facing the first connecting fitting 20b, as shown in Fig. 3, for example, and the connecting fittings 20a and 20c that are closest to the axial connecting portion 11 may be attached facing the same direction. In other words, the connecting fittings 20a, 20b, and 20c in Fig. 3 may be configured as first connecting fittings, and only the connecting fitting 20d may be configured as the second connecting fitting. In other words, if a pair of connecting fittings 20 attached to the connecting parts 12 at both ends in the z direction of the first retaining member 10a are arranged so that one side 22e faces each other, it is possible to suppress a decrease in the connection strength between the first retaining member 10a and 10b and the second retaining member 10c and the third retaining member 10d. In other words, a pair of connecting fittings 20 attached to the connecting parts 12 at both ends in the z direction of the retaining member 10, with one side 22e facing each other, may be arranged at any position in the θ direction (circumferential direction) of the retaining member 10.

Embodiment 2.
An earth retaining structure 200 according to the second embodiment will be described. The earth retaining structure 200 is obtained by partially modifying the members connecting the connecting portions 12 of the earth retaining members 10 constituting the earth retaining structure 100 according to the first embodiment. Note that components having the same functions and actions as those in the first embodiment are given the same reference numerals and their description will be omitted.

15 is a cross-sectional view of a portion of the retaining structure 200 according to the second embodiment. In the retaining structure 200 according to the second embodiment, the portions connected using the second connecting fittings 20 in the retaining structure 100 according to the first embodiment are connected using bolts 41 and nuts 42. Portions that are relatively easy to come off, such as the connecting fittings 20 on the lower side in the z-direction of the retaining structure 1100 according to the comparative example shown in FIG. 12, may be connected using bolts 41 and nuts 42 as fastening members 40. That is, the multiple connecting members connecting the retaining members 10 may include fastening members 40 composed of bolts 41 and nuts 42. Specifically, at least one of the connecting fittings 20c and 20d shown in FIG. 3 may be replaced with the fastening member 40. In the case of the bolts 41 and nuts 42, the decrease in the connecting force due to the shifting of the retaining members 10 is suppressed, so that the retaining structure 200 has the same circumferential variation in strength and rigidity as the first embodiment. In addition, by using connecting fittings 20 other than the fastening members 40, the efficiency of the work of connecting the retaining members 10 is improved.

Embodiment 3.
An explanation will be given of an earth retaining structure 100 according to embodiment 3. The earth retaining structure 100 will be given of the earth retaining structure 100 according to embodiment 1, particularly with regard to the arrangement of the connecting members that connect the axial connecting parts 11 of the earth retaining members 10. Note that components having the same functions and actions as those in embodiment 1 will be given the same reference numerals and their explanation will be omitted.

Figure 16 is a perspective view of an earth retaining structure 100 according to embodiment 3. Figure 17 is an enlarged perspective view of the periphery of the axial connection portion 11 of the earth retaining structure 100 of Figure 16. In embodiment 3, the earth retaining structure 100 is described as being circular when viewed from above as an example, but the earth retaining structure may be rectangular, oval, horseshoe-shaped, or other shapes.

The earth retaining members 10 constituting the annular body 50A and the earth retaining members 10 constituting the annular body 50B are arranged at positions where the connecting plates 19 arranged at the longitudinal ends are shifted in the θ direction. Therefore, as shown in Figures 16 and 17, the earth retaining structure 100 has an axial connecting portion 11 in which the connecting plates 19 that connect the earth retaining members 10a and 10b arranged adjacent to each other in the θ direction are overlapped. The axial connecting portion 11 extends along the z direction. Therefore, the earth retaining structure 100 has an intersection portion where the axial connecting portion 11 and the connecting portion 12 extending in the θ direction intersect to form a T shape. The connecting plate 19 is also called a vertical flange.

The axial connecting portion 11 is connected by a connecting fitting 20. As shown in FIG. 17, the connecting fittings 20 attached to the axial connecting portion 11 are connected from the bottom to the top as connecting fittings 20g1, 20g2, 20g3, and 20g4. The connecting fittings 20g1 to 20g4 attached to these axial connecting portions 11 may be collectively referred to as connecting fittings 20g. Also, the connecting fitting 20g1 may be referred to as the third connecting fitting, and the connecting fittings 20g2 to 20g4, which have one side 22e facing away from the third connecting fitting, may be referred to as the fourth connecting fitting. In the third embodiment, the number of connecting fittings 20g attached to the axial connecting portion 11 is four, but this is not limited to this. In FIG. 17, the cross-sectional shape of the main body 14 of the retaining member 10 is formed into a sine curve-like waveform, and four connecting holes 19a are arranged in accordance with the waveform, and connecting fittings 20g are arranged in each of the connecting holes 19a. In contrast, for example, in the case of the trapezoidal wave-shaped cross-sectional shape shown in FIG. 5, three connecting holes 19a are arranged in accordance with the outer flanges 17 and 18, so that adjacent earth retaining members 10 are connected by three connecting fittings 20g. The wave shape of the cross-sectional shape of the body 14 of the earth retaining member 10 can be changed as appropriate according to the dimension in the z direction, so the position and number of connecting fittings 20g may be changed accordingly. Also, as described in the second embodiment, the connecting fittings 20g and the fastening members 40 may be used together in the axial connecting portion 11 of the earth retaining structure 100.

In the third embodiment, only the connecting fitting 20g1, which is located at the bottom of the connecting fittings 20g arranged in the axial connecting portion 11, is attached facing in the opposite direction to the other connecting fittings 20g2 to 20g4. In other words, the connecting fitting 20g1 is arranged with one side 22e, which faces the direction in which the insertion portion 25 and the clamping portion 23 extend from the connecting fitting body 22, facing in the θ direction, and the other connecting fittings 20g2 to 20g4 are arranged with one side 22e facing in the opposite θ direction.

Figure 18 is a cross-sectional view showing the state in which the retaining member 10 of the retaining structure 100 according to embodiment 3 is displaced by earth pressure. Figure 18 is a schematic diagram of the state in which the retaining member 10a or 10b arranged adjacent to each other in the θ direction is displaced in the r direction. Figures 18(a) and (b) show the state in which the retaining member 10b is displaced to the inside of the retaining structure 100, that is, in the opposite direction to the r direction. Figures 18(c) and (d) show the state in which the retaining member 10a is displaced to the inside of the retaining structure 100, that is, in the opposite direction to the r direction. For example, in the axial connecting portion 11 shown in Figure 17, when the retaining member 10b is displaced inward, the back surface 19c of the connecting plate 19 of the retaining member 10a is displaced so as to come off the abutment portion 23b of the clamping portion 23 of the connecting fitting 20g1 as shown in Figure 18(a). As a result, the force with which the connecting fitting 20g1 holds the connecting plate 19 of the retaining members 10a and 10b is reduced.

On the other hand, as shown in FIG. 18(b), the connecting fittings 20g2 to 20g4 are attached in the opposite direction to the connecting fitting 20g1, so the abutment portion 23b remains in contact with the rear surface 19c of the connecting plate 19. Therefore, the connecting fittings 20g2 to 20g4 can hold the connecting plates 19 of the retaining members 10a and 10b in an overlapping state by the clamping portion 23.

In the state shown in Figures 18(c) and (d), the abutment portion 23b of the connecting fitting 20g1 remains in contact with the back surface 19c of the connecting plate 19. On the other hand, the back surface 19c of the connecting plate 19 of the retaining member 10a of the connecting fittings 20g2 to 20g4 has come off the abutment portion 23b of the clamping portion 23 of the connecting fittings 20g2 to 20g4, and the force holding the connecting plate 19 is reduced.

As described above, in the retaining structure 100 according to the third embodiment, the force of holding the connecting plate 19 of some of the connecting fittings 20g may decrease due to the relative displacement of adjacent retaining members 10 in the circumferential direction. However, as shown in FIG. 17, at least one connecting fitting 20g1 among the connecting fittings 20g installed in one axial connecting section 11 is installed with one side 22e facing in the opposite direction to the other connecting fittings 20g2 to 20g4. Therefore, it is possible to avoid a state in which the holding force of all connecting fittings 20g installed in the axial connecting section 11 decreases. Therefore, it is possible to respond to both cases in which the relative displacement of adjacent retaining members 10a and 10b occurs in the forward and reverse directions.

As shown in FIG. 17, in the third embodiment, only the bottom connecting fitting 20g1 installed in the axial connecting portion 11 is reversed. As shown in FIG. 7, the connecting fitting 20 used in the third embodiment has the tip portion 21 and the clamping portion 23 shifted in the x direction. Therefore, when the connecting plate 19 is fitted into the clamping portion 23 of the connecting fitting 20g1 arranged in a position close to the connecting portion 12, the clamping portion 23 may come into contact with the connecting portion 12 extending in the θ direction. Therefore, by attaching the connecting fitting 20g1 in the reverse direction, there is an advantage in that it is possible to avoid a situation in which the abutment portion 23b of the connecting fitting 20g1 interferes with the connecting portion 12, making it difficult to assemble the connecting fitting 20g1.

In addition, in the retaining structure 100 according to the third embodiment, one of the four connecting fittings 20g installed in the axial connecting portion 11, the connecting fitting 20g1, is installed facing in the reverse direction, but the number and position of the connecting fittings 20g facing in the reverse direction may be changed as appropriate. For example, in the axial connecting portion 11 shown in FIG. 17, one side 22e of the connecting fitting 20g3 may be installed facing in the θ direction. By alternately providing connecting fittings 20g facing in the forward and reverse directions in one axial connecting portion 11, it is possible to suppress a decrease in the holding force of the connecting fitting 20g of the axial connecting portion 11 regardless of the relative displacement of the adjacent retaining members 10.

Embodiment 4.
An explanation will be given of an earth retaining structure 400 according to embodiment 4. The earth retaining structure 400 shows an example of the arrangement of connecting fittings 20 that connect the connecting portions 12 of the earth retaining members 10 that constitute the earth retaining structure 100 according to embodiment 1. Note that components having the same functions and actions as those in embodiment 1 are given the same reference numerals and their explanations are omitted.

Figure 19 is a schematic diagram illustrating an example of the arrangement of connecting fittings 20 of an earth retaining structure 400 according to embodiment 4. Figure 19 shows the earth retaining structure 400 as viewed from the inside. The connecting fittings 20 shown solid in Figure 19 are arranged with one side 22e, which is the direction in which the tip portion 21 and clamping portion 23 extend, facing in the opposite direction to the connecting fittings 20 shown in white.

In the retaining structure 400 according to the fourth embodiment, as in the first embodiment, the connecting fitting 20c located at the end of the retaining member 10 in the θ direction is arranged with one side 22e facing in the opposite direction to the connecting fitting 20a arranged opposite in the z direction. And, for example, when focusing on the connecting portion 12a of the two retaining members 10a and 10c connected in the z direction, the connecting fittings 20 arranged adjacent to each other in the θ direction (circumferential direction) of the retaining member 10 are arranged so that their directions are opposite to each other.

In the example shown in FIG. 19, six connecting fittings 20 are arranged at the connecting portion 12a of the two retaining members 10a and 10c, so that the connecting fittings 20a, 20e, and 20d are in the forward direction and the connecting fittings 20b, 20f, and 20c are in the reverse direction, and can be arranged alternately.

In contrast, for example, when five connecting fittings 20 are installed in the connecting portion 12a, they cannot be arranged alternately, so first the direction of the connecting fittings 20a and 20c closest to the axial connecting portion 11 is determined, and the connecting fittings 20b and 20d adjacent to these connecting fittings 20a and 20c are installed so that they face in the opposite direction to the connecting fittings 20a and 20c. In other words, in the connecting portion 12 of two earth retaining members 10 connected in the z direction, the connecting fittings 20 closest to the axial connecting portions 11 at both ends are arranged so that they face in the opposite direction, and then the connecting fittings 20 arranged adjacent to these connecting fittings 20 are arranged in the opposite direction. By configuring in this way, even if a relative displacement occurs between the two earth retaining members 10 connected in the z direction, it is possible to prevent the connecting fittings 20 installed in the connecting portion 12 from coming off.

The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies. Parts of the configurations may be omitted or modified without departing from the spirit of the invention.

10 soil retaining member, 10A soil retaining member, 10B soil retaining member, 10a (first) soil retaining member, 10b (first) soil retaining member, 10c (second) soil retaining member, 10d (third) soil retaining member, 11 axial connecting portion, 12 connecting portion, 12a (first) connecting portion, 12b (second) connecting portion, 13 flange portion, 13a connecting hole, 13b tip portion, 13c back surface, 14 main body, 15 web portion, 16 inner flange portion, 17 outer flange portion, 19 connecting plate, 20 connecting fitting, 20a (first) connecting fitting, 20b (first) connecting fitting, 20c (second) connecting fitting, 20d connecting fitting, 20e (first) connecting fitting, 20f (first) connecting fitting, 20g connecting fitting, 20g1 Connecting fitting, 20g2 connecting fitting, 20g3 connecting fitting, 20g4 connecting fitting, 21 tip, 21a tip, 21b plate surface, 22 connecting fitting body, 22a clamping end, 22b insertion end, 22c edge, 22d edge, 23 clamping portion, 23b abutment portion, 25 insertion portion, 26 protrusion, 50 ring body, 50A ring body, 50B ring body, 92 natural ground, 93 space portion, 100 earth retaining structure, 100A earth retaining structure, 120 connecting fitting, 200 earth retaining structure, 1100 earth retaining structure, C central axis, N neutral axis.

Claims (14)

A retaining structure constructed by connecting a plurality of retaining members, the ends of which are shifted in a first direction, in a second direction perpendicular to the first direction using a plurality of connecting members, and holding down soil in the ground with the plurality of retaining members to form a space,
Each of the plurality of earth retaining members is
A main body that is placed along the natural ground;
a flange portion protruding from an edge of the main body in the second direction toward the space portion,
The flange portion is
A connecting hole is formed through the flange portion in the thickness direction,
The plurality of connecting members include
A plurality of connecting fittings are included.
The plurality of connecting fittings include
The flange portions of the adjacent earth retaining members are attached to a connecting portion formed by overlapping the flange portions of the adjacent earth retaining members,
A connecting fitting body,
an insertion portion formed by bending one end of a member constituting the connecting fitting body toward one surface of the connecting fitting body;
a clamping portion formed by bending the other end of the member constituting the connecting fitting body toward the one surface side into a U-shape,
The insertion portion is
The connecting holes are inserted through the connecting holes formed in each of the plurality of adjacent earth retaining members,
The clamping unit is
The flange portions of the plurality of adjacent earth retaining members are sandwiched in an overlapping state,
The plurality of connecting fittings include
A retaining structure comprising a first connecting fitting and a second connecting fitting installed at the connecting portion with the one side facing in a different direction relative to the first connecting fitting. The plurality of earth retaining members include
A first retaining member;
a second retaining member having an end position in the first direction shifted relative to the first retaining member and connected to one of the flange portions of the first retaining member in the second direction;
a third retaining member having an end position in the first direction shifted relative to the first retaining member and connected to the other flange portion of the first retaining member in the second direction;
When the connection portion between the first soil retaining member and the second soil retaining member is a first connection portion, and the connection portion between the first soil retaining member and the third soil retaining member is a second connection portion,
Among the plurality of connecting fittings installed in the second connecting portion, at least the second connecting fitting is disposed at the end of the first retaining member,
The retaining structure according to claim 1 , wherein the first connecting fitting is arranged at a position facing the second connecting fitting among the plurality of connecting fittings installed at the first connecting portion. The plurality of earth retaining members include
A first retaining member;
a second retaining member having an end position in the first direction shifted relative to the first retaining member and connected to one of the flange portions of the first retaining member in the second direction;
a third retaining member whose end position in the first direction is shifted relative to the first retaining member and which is connected to the other flange portion of the first retaining member in the second direction;
When the connection portion between the first soil retaining member and the second soil retaining member is a first connection portion, and the connection portion between the first soil retaining member and the third soil retaining member is a second connection portion,
In the second connecting portion, the second connecting fitting has
The retaining structure according to claim 1 , which is positioned closer to an end of the first retaining member than the first connecting fitting. The retaining structure according to claim 2 or 3, wherein the second connecting fittings are the multiple connecting fittings that are arranged at the ends of the first retaining member among the multiple connecting fittings installed in the second connecting portion. The retaining structure according to claim 2 or 3, wherein the first connecting fitting is arranged adjacent to the second connecting fitting arranged at the end of the first retaining member in the first direction among the plurality of connecting fittings installed in the second connecting portion. Each of the plurality of earth retaining members is
a connecting plate provided on an edge of the main body in the first direction,
The connecting plate is
A connecting hole is formed through the connecting plate in the thickness direction,
The plurality of connecting fittings include
The connecting plates of the adjacent earth retaining members are attached to an axial connecting portion formed by overlapping the connecting plates of the adjacent earth retaining members,
The insertion portion is
The connecting hole is inserted into each of the plurality of earth retaining members adjacent to each other in the first direction,
The clamping unit is
The connecting plates of the plurality of adjacent earth retaining members are sandwiched in a stacked state,
The plurality of connecting fittings include
A retaining structure as described in any one of claims 1 to 5, comprising a third connecting fitting and a fourth connecting fitting installed at the connecting portion with the one side facing in a different direction relative to the third connecting fitting. A retaining structure constructed by connecting a plurality of retaining members, the ends of which are shifted in a first direction, in a second direction perpendicular to the first direction using a plurality of connecting members, and holding down soil in the ground with the plurality of retaining members to form a space,
Each of the plurality of earth retaining members is
A main body that is placed along the natural ground;
A connecting plate provided on an edge of the main body in the first direction;
a flange portion protruding from an edge of the main body in the second direction toward the space portion,
The connecting plate is
A connecting hole is formed through the connecting plate in the thickness direction,
The plurality of connecting members include
A plurality of connecting fittings are provided to connect two adjacent soil retaining members in the first direction among the plurality of soil retaining members ,
The plurality of connecting fittings include
The connecting plates of the two adjacent earth retaining members are attached to an axial connecting portion formed by overlapping the connecting plates of the two adjacent earth retaining members,
A connecting fitting body,
an insertion portion formed by bending one end of a member constituting the connecting fitting body toward one surface of the connecting fitting body;
a clamping portion formed by bending the other end of the member constituting the connecting fitting body toward the one surface side into a U-shape,
The insertion portion is
The connecting hole is inserted into each of the two adjacent earth retaining members,
The clamping unit is
The connecting plates of the two adjacent earth retaining members are sandwiched in an overlapping state,
The plurality of connecting fittings include
An earth retaining structure comprising: a third connecting fitting; and a fourth connecting fitting installed on the axial connecting portion with the one side facing in a different direction relative to the third connecting fitting. The retaining structure according to claim 6 or 7, wherein the fourth connecting fitting is arranged adjacent to the third connecting fitting in the second direction among the multiple connecting fittings installed in the axial connecting portion. The retaining structure according to any one of claims 1 to 8, wherein the second direction is the direction of gravity. The retaining structure according to any one of claims 1 to 9, wherein the bent portion of the clamping portion is formed at an angle to the longitudinal direction of the connecting fitting body. The tip of the insertion portion is
The flange portion is bent in a direction along the flange portion, and the insertion portion is abutted against a back surface around the connecting hole when the insertion portion is inserted into the connecting hole,
The flange portion is
The retaining structure described in any one of claims 1 to 10, wherein the connecting fitting body is rotated around the insertion portion inserted into the connecting hole, so that the connecting fitting body enters the clamping portion and is clamped. The opening width of the inlet of the clamping part is
The retaining structure according to any one of claims 1 to 11, which is formed narrower than the thickness of the overlapping flange portions. The width of the clamping portion is
The retaining structure according to any one of claims 1 to 12, which is formed wider than the width of the insertion portion. The plurality of connecting members include
The retaining structure according to any one of claims 1 to 13, comprising fastening members constituted by bolts and nuts.

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