JP2021191931A - Support structure for soil retain wall - Google Patents

Abstract

To provide a support structure for a soil retain wall allowing necessary displacement suppression performance to be efficiently secured only by installing a widening part in part.SOLUTION: A support structure for a soil retain wall 1 is provided with a ground improvement part 2 in a buttress shape under the ground surface. The ground improvement part 2 extends in a direction generally orthogonal to a wall surface 11 of the soil retain wall 1, and widening parts 3A and 3B are formed at a middle part and an edge of the extending direction, respectively. The ground improvement part 2 is formed by continuously arranging column shaped improvement bodies 22 on a body part 21 extending in a direction generally orthogonal to the wall surface 11 of the soil retain wall 1, and the widening parts 3A and 3B are formed by column shaped improvement bodies 31 disposed to be adjacent to both sides of the body part 21.SELECTED DRAWING: Figure 1

Description

The present invention relates to a support structure for a retaining wall in which a buttress-like ground improvement portion is provided below the ground surface.

When constructing a structure underground or burying a box culvert, etc., the ground is dug down by providing a retaining wall to protect the excavated surface. In urban areas where buildings and public facilities are concentrated, various displacement suppression measures are taken in order to suppress the effects of excavation, such as deformation or subsidence of the surrounding ground, as much as possible.

For example, Patent Document 1 discloses a construction method in which a beam-shaped soil straddle is provided inside a retaining wall and the facing mountain retaining walls are connected in the ground below the bottom of excavation. Further, in Patent Documents 1 and 2, a retaining wall (soil buttress) is constructed by providing a soil cement column column of the same length at a certain depth on the ground on the excavation side of the root of the retaining wall, and the earth retaining wall is retained. It is described to reduce the amount of horizontal displacement of the wall.

Japanese Unexamined Patent Publication No. 7-127064 Japanese Unexamined Patent Publication No. 2003-90043

However, the resistance to the fall of the retaining wall that can be expected from the flat plate-walled soil buttress is mainly the resistance that the edge and the lower edge opposite to the retaining wall receive from the ground, and the friction between the side surface of the soil buttress and the ground. The degree to which resistance is added (see FIG. 4 (b) described later). For this reason, in order to increase the resistance to rotation and sliding of the retaining wall, the overall shape of the soil buttress must be increased in order to lengthen the edge and the lower edge, which is not efficient.

Therefore, an object of the present invention is to provide a support structure for a retaining wall that can efficiently secure the required displacement restraining performance only by partially providing a widening portion.

In order to achieve the above object, the support structure of the earth retaining wall of the present invention is a support structure of the earth retaining wall in which a buttress-like ground improvement portion is provided below the ground surface, and the ground improvement portion is the soil. It is characterized in that it is stretched in a direction substantially orthogonal to the wall surface of the buttress, and a widening portion is formed in the middle of the stretching direction and at at least one end edge.

Here, the ground improvement portion is formed by continuously providing a columnar improvement body in a main body portion extending in a direction substantially orthogonal to the wall surface of the earth retaining wall, and the widening portion is the widening portion. It can be configured to be formed by columnar improved bodies provided adjacent to both sides of the main body.

Further, the widening portions can be provided at a plurality of locations at intervals in the stretching direction of the main body portion. Further, an integral core material may be embedded so as to straddle the main body portion and the widening portion. Further, the widening portion may be formed in a shape in which the amount of protrusions gradually increases as the distance from the retaining wall increases in a plan view.

In the support structure of the retaining wall of the present invention configured as described above, in the buttress-shaped ground improvement portion extending in a direction substantially orthogonal to the wall surface of the retaining wall, the middle and the edge in the extending direction A widening portion is formed at at least one place.

For this reason, the resistance due to the protrusions of the partially enlarged widening part is added to the normal displacement suppression performance of the buttress-shaped ground improvement part, and the required displacement suppression performance is efficiently secured. You will be able to.

The ground improvement portion provided with such a widening portion can be easily provided by the columnar improvement body. Further, by providing a plurality of widening portions at intervals in the stretching direction of the main body portion, it is possible to improve the displacement suppression performance per unit length.

Further, even if there is a risk of shear failure due to the force transmitted from the main body to the widening portion only by the joint strength of the ground improvement, if an integral core material is embedded straddling the main body and the widening portion, Shear failure can be prevented by the resistance of the core material itself. On the other hand, shear failure can also be prevented by forming the widening portion in a shape in which the amount of protrusions gradually increases as the distance from the retaining wall increases in a plan view.

It is a perspective view explaining the schematic structure of the support structure of the earth retaining wall of this embodiment. It is a perspective view explaining the structure which the widening part is provided in the middle of the extending direction of the earth retaining wall. It is a perspective view explaining the structure which the widening part is provided in the edge in the extending direction of the earth retaining wall. It is a figure explaining the resistance to the rotational force of the earth retaining wall provided with the widening part in the ground improvement part, (a) is the explanatory view about the support structure of the earth retaining wall shown in FIG. 2, (b) is It is explanatory drawing about the support structure of the earth retaining wall shown in FIG. It is a figure explaining the structure of the support structure of the earth retaining wall provided with the widening part of Example 1. FIG. It is a top view when the thickness gradually increases. It is a top view explaining the structure of the support structure of the earth retaining wall in which the core material was embedded in the widening part of Example 2. FIG. It is a figure explaining the structure of the support structure of the earth retaining wall of Example 2, (a) is the explanatory view when the resin core material is embedded in the widening part, (b) is the steel core material. It is explanatory drawing when is embedded in a widening part. It is a perspective view explaining the structure of the support structure of the earth retaining wall provided in the corner portion of the earth retaining wall of Example 3. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view illustrating a schematic configuration of a support structure for a retaining wall according to the present embodiment.
The earth retaining wall 1 is provided to protect the vertical excavation surface that appears when the ground G is excavated as it is. Here, the wall surface 11 exposed on the excavation side of the earth retaining wall 1 is almost vertically exposed.

The earth retaining wall 1 may have any form, and can be formed into a wall, for example, by arranging a plurality of soil cement columns in a row. Further, the earth retaining wall 1 can also be constructed by using a steel sheet pile, a parent pile horizontal sheet pile, a steel pipe sheet pile, an underground continuous wall, a muddy water solidification wall, and the like.

The support structure of the earth retaining wall of the present embodiment is provided on the excavated surface side with respect to the earth retaining wall 1. A portion deeper than the excavation bottom surface S, which is the bottom of the excavation space when the ground G is dug down, becomes the root of the earth retaining wall 1, and a support structure for the earth retaining wall is provided in order to suppress the horizontal displacement of the earth retaining wall 1. ..

The ground improvement portion 2, which is a support structure for the earth retaining wall of the present embodiment, is provided in the shape of a buttress of the earth retaining wall 1. That is, the rooting portion that is the lower part of the earth retaining wall 1 is provided as a buttress that supports the excavation space side.

When the pressure acting on the excavated surface side is released by excavation, the earth retaining wall 1 becomes unstable and tends to tilt. The typical deformation pattern of the earth retaining wall 1 is caused by the unevenness of the pressure, and the earth retaining wall 1 protrudes to the S side of the excavation bottom surface. Therefore, by providing the buttress-shaped ground improvement portion 2 in the moving direction of the rooting of the earth retaining wall 1, the displacement of the earth retaining wall 1 can be suppressed by the resistance thereof.

The ground improvement portion 2 stretched in the vertical direction is also stretched in a direction substantially orthogonal to the wall surface 11 of the retaining wall 1. By providing the resistor extending in the displacement direction of the earth retaining wall 1 in this way, the displacement suppressing performance can be exhibited.

The ground improvement unit 2 is a soil buttress constructed by stirring the ground while mixing, for example, a cement-based solidifying material. For example, the ground improvement portion 2 can be formed by a columnar soil cement column constructed by injecting cement milk while stirring the ground with an auger or a stirring blade. Further, the ground improvement unit 2 can also be provided by a jet stirring method in which the solidifying material is mixed with the ground while being jetted with a high pressure jet.

The ground improvement portion 2 of the present embodiment is formed in the main body portion 21 stretched in the stretching direction Y substantially orthogonal to the wall surface 11 of the earth retaining wall 1 and in the middle and the end edge of the main body portion 21 in the stretching direction Y. It is mainly composed of widening portions 3A and 3B.

When the main body portion 21 is provided by a columnar improved body 22 such as a soil cement column, the main body portion 21 is continuously provided in the stretching direction Y. For example, a continuous soil cement colonnade wall can be obtained by wrapping a part of a cross section with a multi-screw kneading auger machine equipped with a plurality of augers.

The widening portions 3A and 3B can also be provided by a columnar improved body 31 such as a soil cement column. Here, with reference to FIGS. 2 and 3, the widening portion 3A provided in the middle of the stretching direction Y and the widening portion 3B provided at the edge edge will be described separately.

FIG. 2 shows an example in which a plurality of widening portions 3A and 3A are provided at intervals in the stretching direction Y of the main body portion 21. The widening portion 3A is formed so that both sides of the side surface of the main body portion 21 are projected in the widening direction X orthogonal to the stretching direction Y in a plan view.

Specifically, the widening portion 3A can be formed by providing the columnar improved bodies 31 and 31 adjacent to both sides of the columnar improved body 22 of the main body portion 21, respectively. For example, when the main body 21 is constructed by a 3-axis multi-axis kneading auger machine, the widening portion is rotated by 90 degrees in a plan view from the stretching direction Y to the widening direction X. 3A can be constructed.

On the other hand, FIG. 3 shows an example in which the widening portion 3B is provided on the opposite end edge of the retaining wall 1 in the extending direction Y of the main body portion 21. The widening portion 3B is formed so as to expand the area of the edge of the main body portion 21.

As shown in FIG. 1, the ground improvement portion 2 and the widening portions 3A and 3B have a shape such that the upper end surface is exposed to the excavation bottom surface S as a result of excavation, for example. A plurality of ground improvement portions 2 having the widening portions 3A and 3B are provided at intervals in the width direction of the retaining wall 1.

Subsequently, with reference to FIG. 4, the resistance to the rotational force of the earth retaining wall 1 provided with the widening portions 3A and 3B in the ground improvement portion 2 (2A, 2B) will be described. First, the support structure of the earth retaining wall shown in FIG. 2 will be described with reference to FIG. 4 (a).

In the case of a general wall-shaped soil buttress, when a rotational force R acts so that the upper part of the earth retaining wall 1 protrudes to the excavation bottom S side, the edge of the soil buttress on the opposite side of the earth retaining wall 1 acts. Rotation and sliding are suppressed by the resistance P1 received from the ground, the resistance P2 received from the ground by the lower edge of the soil buttress, and the resistance P3 due to the friction between the side surface of the soil buttress and the ground.

In addition, since the ground improvement portion 2A shown in FIG. 2 includes a widening portion 3A protruding in the widening direction X, rotation and sliding are suppressed by the widening resistance TA due to this catching.

This widening resistance TA is increased at each location where the widening portions 3A are provided by providing a plurality of widening portions 3A and 3A at intervals in the stretching direction Y. Further, as shown in FIG. 2, by providing the widening portion 3A so as to be line-symmetrical with respect to the stretching direction Y of the main body portion 21, it is possible to prevent an unbalanced load from being generated.

On the other hand, the ground improvement portion 2B of the support structure of the earth retaining wall shown in FIG. 3 has a widening portion 3B extending in the widening direction X at the end edge of the main body portion 21, as shown in FIG. 4 (b). In addition, the widening resistance TB due to this expanded area is added, and rotation and sliding are suppressed. That is, the resistance of the edge of the ground improvement portion 2B is the magnitude obtained by adding the widening resistance TB received by the widening portion 3B to the resistance P1 received by the edge of the main body portion 21 of the general soil buttress.

Next, a method of constructing the support structure of the earth retaining wall of the present embodiment will be described.
First, the earth retaining wall 1 is constructed. The earth retaining wall 1 can be constructed, for example, by injecting cement milk while excavating the ground G from the ground surface with an auger to provide a soil cement column. The soil cement columns for the earth retaining wall 1 are continuously provided in the width direction of the earth retaining wall 1.

That is, a colonnade wall is constructed by wrapping both sides of the earth retaining wall 1 in the width direction with adjacent soil cement columns. If necessary, a core material such as H-shaped steel or a steel pipe can be inserted into the soil cement column for the earth retaining wall 1.

Further, as shown in FIG. 1, a main body portion 21 and widening portions 3A and 3B, which are ground improvement portions 2, are provided on the ground below the excavation bottom surface S formed when excavating below the ground surface. The columnar improved bodies 22 and 31 constituting the main body portion 21 and the widening portions 3A and 3B can be constructed by injecting cement milk while excavating the ground G from the ground surface with an auger.

Further, when the columnar improved body 22 is constructed by the multi-axis kneading auger machine, for example, three rows of columnar improved bodies 22, 22, 22 are formed by one propulsion. The main body 21 is constructed by pointing the multi-axis kneading auger machine so that three rows are lined up in the stretching direction Y, and by rotating the auger of the multi-axis kneading auger machine 90 degrees and pointing it in the widening direction X, the widening part 3A , 3B and the columnar improved body 22 intersecting the widening portions 3A and 3B are constructed.

The construction of the ground improvement portion 2 is also performed at positions spaced apart in the width direction of the retaining wall 1. After constructing the earth retaining wall 1 and the ground improvement part 2 supporting the earth retaining wall 1 in this way, excavation of the ground G is started. The excavation of the ground G is carried out by using a girder or the like as necessary.

Further, the excavation is performed while removing the columnar improved bodies 22 and 31 above the excavation bottom surface S with a breaker or the like. The result of such excavation is as shown in FIG.

Next, the operation of the support structure of the earth retaining wall of the present embodiment will be described.
In the support structure of the earth retaining wall of the present embodiment configured as described above, the extension direction Y in the buttress-shaped ground improvement portion 2 extending in a direction substantially orthogonal to the wall surface 11 of the earth retaining wall 1. Widening portions 3A and 3B are formed in the middle of and at least one of the edge edges.

For this reason, the resistance due to the protrusions of the partially enlarged widening portions 3A and 3B is added to the normal displacement suppression performance of the buttress-shaped ground improvement portion 2, and the required displacement suppression performance is efficient. Can be secured.

The ground improvement portion 2 provided with such widening portions 3A and 3B can be easily provided by the columnar improvement bodies 22 and 31. Further, by providing a plurality of widening portions 3A and 3B at intervals in the stretching direction Y of the main body portion 21, the locations where resistance is generated are dispersed, and the displacement suppression performance per unit length can be improved.

In short, it is possible to increase the resistance corresponding to the protruding area only by partially providing the columnar improved body 31 so as to project from the main body 21, so that the shape of the entire main body is not enlarged. It is efficient because it requires only a small area for ground improvement. That is, in order to provide the resistance required to prevent the earth retaining wall 1 from rotating or sliding, the main body portion 21 is not enlarged, but the widening portions 3A and 3B are partially provided to provide the entire soil cement. If the amount of construction can be reduced, the construction cost and construction period can be reduced.

Hereinafter, an embodiment different from the retaining wall support structure described in the above embodiment will be described with reference to FIG. The description of the same or equivalent parts as those described in the above-described embodiment will be described with the same terms or the same reference numerals.

The widened portion of the ground improvement portion described as the support structure of the earth retaining wall of the first embodiment has a thickness in the extending direction Y of the main body portion 21 in a plan view as compared with the widened portions 3A and 3B described in the above embodiment. Is thickly formed.

That is, the load acting on the ground improvement portions 2, 2A and 2B from the earth retaining wall 1 is transmitted to the main body portion 21 extending in the stretching direction Y, but the widening portions 3A and 3B protruding in the widening direction X are transmitted. At the provided location, a shearing force acts between the widening portions 3A and 3B and the main body portion 21. As long as this shearing force is within the range of the joint strength between the widening portions 3A and 3B and the main body portion 21, the widening portions 3A and 3B having a thickness of one row may be used.

On the other hand, in order to increase the joint strength so that shear failure does not occur when the shear force becomes large, the ground improvement portions 2C and 2D provided with the widening portions 3C and 3D described in the first embodiment are used. can do. FIG. 5A shows a widening portion 3C having a certain thickness thicker than the widening portions 3A and 3B described in the above embodiment.

Specifically, the widening portion 3C is formed by two rows of columnar improved bodies 31 protruding in the widening direction X on both sides of the main body portion 21. By increasing the thickness of the widened portion 3C in a plan view to increase the contact area with the main body portion 21 and disperse the stress, the proof stress against shearing force can be increased.

For example, the main body 21 is constructed by a multi-axis kneading auger equipped with a 3-axis auger, and the direction of the arrangement of the augers is rotated by 90 degrees at the place where the widening portion 3C is provided, and the columnar improved body on the retaining wall 1 side is used. The widening portion 3C is formed by constructing 31,22,31 and further constructing a columnar improved body 31,22,31 adjacent to it.

Subsequently, the direction of the arrangement of the augers is rotated by 90 degrees, the columnar improved body 22 of the main body 21 is constructed again, and the direction of the arrangement of the augers is rotated by 90 degrees at the place where the next widening portion 3C is provided. The widening portion 3C of is constructed.

On the other hand, FIG. 5B shows a widening portion 3D when the amount of protrusions gradually increases in addition to the thickness. That is, the widening portion 3D provided in the ground improvement portion 2D is formed in a shape in which the amount of protrusions in the widening direction X gradually increases as the distance from the retaining wall 1 increases in a plan view.

For example, in the widening portion 3D formed in the shape of a plan view, the columnar improved body 22 in one row of the main body portion 21 extending in the stretching direction Y becomes the columnar improved bodies 31 and 31 in two rows on the retaining wall 1 side. Therefore, three rows of columnar improved bodies 31, 31, 31 are formed adjacent to each other.

Then, the columnar improved bodies 22 are arranged in one row again to construct the main body portion 21, and at the location of the second widening portion 3D, the widening portion 3D having a plan view table shape is formed by the columnar improved bodies 31 in the second row and the third row. Will be built. By forming the widening portion 3D in a shape in which the amount of protrusions gradually increases from the earth retaining wall 1 side where the load is generated, the force can be transmitted smoothly without stress concentration, and the resistance to shearing force is also increased. be able to.

In the support structure of the earth retaining wall of the first embodiment configured in this way, the amount of protrusions gradually increases as the width increases from the widening portion 3C in which the thickness in the stretching direction Y is thick in the plan view and the earth retaining wall 1 in the plan view. By providing the widening portion 3D having a shape to be formed in the ground improvement portions 2C and 2D, shear failure can be prevented.
Since other configurations and actions and effects are substantially the same as those of the above-described embodiment or other examples, the description thereof will be omitted.

Hereinafter, an embodiment different from the above-described embodiment and the retaining wall support structure described in the first embodiment will be described with reference to FIGS. 6 and 7. The description of the same or equivalent parts as those described in the above-described embodiment or the first embodiment will be described with the same terms or the same reference numerals.

In the second embodiment, similarly to the first embodiment, the ground improvement unit 2E having improved the yield strength against a large shearing force will be described. FIG. 6 is a plan view for explaining the configuration of the ground improvement portion 2E provided with the widening portion 3E of the second embodiment.

The ground improvement portion 2E includes a main body portion 21 extending from the retaining wall 1 in the stretching direction Y in a plan view, a widening portion 3E protruding in the widening direction X so as to be substantially orthogonal to the main body portion 21, and a main body. It is mainly composed of an integral core material 5 embedded so as to straddle the portion 21 and the widening portion 3E.

The core material 5 is a rectangular member formed in the shape of a strip or the like, and is formed of a material having higher rigidity and tensile strength than the surrounding soil cement. For example, it is inserted in the center of the stretching direction Y in the plan view of the widening portion 3E spreading in the widening direction X so that the edge of the strip is on the upper surface.

By arranging the core material 5 oriented so as to counter the shearing force generated between the main body portion 21 and the widening portion 3E, the bearing capacity of the ground improvement portion 2E against the shearing force can be increased. On the other hand, the core material 5 must not interfere with excavation.

Therefore, the core material 5A can be formed of a machinable material such as synthetic resin. FIG. 7A is a diagram illustrating a case where the resin core material 5A is embedded in the widening portion 3E. Since the resin core material 5A can be cut by an excavator, a backhoe, or the like, it can be buried above the excavation bottom surface S. That is, when the widening portion 3E is continuously provided from the ground surface to the lower edge of the ground improvement portion 2E, the core material 5A having the same length as the widening portion 3E can be inserted.

On the other hand, the core material 5B can also be formed from a steel material such as a shaped steel. FIG. 7B is a diagram illustrating a case where the steel core material 5B is embedded in the widening portion 3E. Since the steel core material 5B hinders excavation of the ground G by an excavator, a backhoe, or the like, it is buried only below the excavation bottom surface S. That is, even when the widening portion 3E is continuously provided from the ground surface to the lower edge of the ground improvement portion 2E, the short core material 5B to be embedded only deeper than the excavation bottom surface S is inserted.

In the case of the support structure of the earth retaining wall of the second embodiment configured in this way, even if a large force that causes shear failure acts only by the joint strength due to the ground improvement, the main body portion 21 and the widening portion 3E Since the integral core materials 5, 5A and 5B are embedded across the core material 5, 5A and 5B, the resistance due to the core materials 5, 5A and 5B itself is added, and shear failure can be prevented.
Since other configurations and actions and effects are substantially the same as those of the above-described embodiment or other examples, the description thereof will be omitted.

Hereinafter, an embodiment different from the above-described embodiment and the retaining wall support structure described in Examples 1 and 2 will be described with reference to FIG. The description of the same or equivalent parts as those described in the above-described embodiment or Examples 1 and 2 will be described with the same terms or the same reference numerals.

In the above-described embodiments and Examples 1 and 2, the widening portion 3A-3E having a shape symmetrical with respect to the main body portion 21 in a plan view, that is, a shape symmetrical with respect to the stretching direction Y has been described. The shape of the widened portion is not limited to the symmetrical shape.

FIG. 8 shows a diagram schematically explaining the configuration of the support structure of the earth retaining wall provided at the corner portion of the earth retaining wall 1, 1A. When the earth retaining wall 1A orthogonal to the wall surface 11 of the earth retaining wall 1 is provided, the displacement in the vicinity of the side edge of the first earth retaining wall 1 is suppressed by the second earth retaining wall 1A.

The stress distribution Q in FIG. 8 shows a state in which the stress acting from the first retaining wall 1 side gradually decreases toward the second retaining wall 1A. Therefore, the resistance of the ground improvement portion 2F provided at the corner portion can also be reduced.

Specifically, when there is no difference in the magnitude of stress on both sides of the main body portion 21, line-symmetrical widening portions 3A and 3B are provided as in the ground improvement portion 2 on the left side. On the other hand, when there is a difference in stress between the left and right sides of the main body 21, a widening portion 3F asymmetric with respect to the stretching direction Y is provided by reducing the amount of protrusions on the side where the magnitude of the applied stress is small. be able to.

The left and right resistance forces of the widening portion 3F can be adjusted by adjusting the inclination between the stretching direction Y and the widening direction X1 and adjusting the amount of protrusions on the left and right. As can be seen from the support structure of the earth retaining wall of the third embodiment configured in this way, the widening portions 3A, 3B, and 3F having an arbitrary shape such as left-right symmetry and left-right asymmetry are provided according to the state of the stress to be resisted. Can be built.
Since other configurations and actions and effects are substantially the same as those of the above-described embodiment or other examples, the description thereof will be omitted.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments and examples, and the design changes to the extent that the gist of the present invention is not deviated. Is included in the present invention.

For example, in the above-described embodiments and examples, the ground improvement portions 2, 2A-2F in which the main body portion 21 is formed by the columnar improvement body 22 in one row has been described, but the present invention is not limited to this, and the columnar improvement body is not limited thereto. It is also possible to make a thick ground improvement part by continuously providing a plurality of rows in the width direction of the earth retaining wall.

Further, in the above-described embodiments and examples, the case where a plurality of widening portions 3A-3F are provided at intervals in the stretching direction Y has been described, but the present invention is not limited to this, and one in the middle of the main body portion 21 The widening portion 3A may be provided only at a location, or the widening portion 3B may be provided only at the edge.

1: Earth retaining wall 11: Wall surface 2, 2A-2F: Ground improvement part 21: Main body part 22: Columnar improvement body 3A-3F: Widening part 31: Columnar improvement body 5,5A, 5B: Core material G: Ground S: Excavation bottom Y: Extension direction

Claims (5)

It is a support structure of a retaining wall in which a buttress-like ground improvement part is provided below the ground surface.
The ground improvement portion is stretched in a direction substantially orthogonal to the wall surface of the retaining wall, and a widening portion is formed in the middle of the stretching direction and at at least one end edge of the retaining wall. Support structure. The ground improvement portion is formed by continuously providing a columnar improvement body in a main body portion extending in a direction substantially orthogonal to the wall surface of the earth retaining wall.
The support structure for a retaining wall according to claim 1, wherein the widening portion is formed by columnar improved bodies provided adjacent to both sides of the main body portion. The support structure for a retaining wall according to claim 2, wherein the widening portions are provided at a plurality of locations at intervals in the stretching direction of the main body portion. The support structure for a retaining wall according to claim 2 or 3, wherein an integral core material is embedded so as to straddle the main body portion and the widening portion. The support structure for a retaining wall according to any one of claims 1 to 4, wherein the widening portion is formed in a shape in which the amount of protrusions gradually increases as the distance from the retaining wall increases in a plan view.

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