JP2021046705A - Ground improvement structure - Google Patents

Abstract

To reduce the number of columnar improved bodies.SOLUTION: A ground improvement structure 20 comprises: a plurality of columnar improved bodies 30 formed on a ground 10 supporting an embankment 12; an overhanging improvement portion 40 formed on the ground 10 and projecting outward from an upper part of the columnar improved body 30; and a wall-shaped improved body 50 formed on the ground 10 and connecting the adjacent columnar improved bodies 30.SELECTED DRAWING: Figure 1

Description

The present invention relates to a ground improvement structure.

A ground improvement structure is known in which a plurality of columnar improved bodies (improved pillar bodies) are formed on the soft ground supporting the embankment (see, for example, Patent Document 1).

Further, as a ground improvement body, a ground improvement body including a pile-shaped solidifying portion and an enlarged solidifying portion integrated with an upper end portion of the pile-shaped solidifying portion is known (see, for example, Patent Document 2).

Further, as a ground improvement device for creating a ground improvement body on the ground, a ground improvement device capable of increasing the diameter of the ground improvement body is known (see, for example, Patent Document 3).

Japanese Unexamined Patent Publication No. 2005-299174 Japanese Unexamined Patent Publication No. 2008-144386 Patent No. 6397147

For example, in the ground improvement structure disclosed in Patent Document 1, a plurality of columnar improvement bodies are provided so that the shear angle in the embankment with respect to the peripheral edge of the upper surface of the columnar improvement body and the internal friction angle of the embankment satisfy a predetermined relationship. By forming, the number of columnar improved bodies is reduced.

However, there is room for further improvement in order to reduce the number of columnar improved bodies.

An object of the present invention is to reduce the number of columnar improved bodies in consideration of the above facts.

The ground improvement structure according to claim 1 includes a plurality of columnar improvement bodies formed on the ground supporting the embankment, an overhang improvement portion formed on the ground and projecting outward from the upper part of the columnar improvement body. It includes a wall-shaped improved body formed on the ground and connecting adjacent columnar improved bodies.

According to the ground improvement structure according to claim 1, a columnar improvement body, an overhang improvement part, and a wall-like improvement body are formed on the ground supporting the embankment. The overhanging improvement part projects from the upper part of the columnar improved body to the outside. This overhanging improvement section increases the support area of the columnar improvement body that supports the embankment. Thereby, in the present invention, the distance between the adjacent columnar improved bodies can be widened while reducing the ground subsidence under the embankment and the ground deformation around the embankment as compared with the columnar improved body having no overhanging improved portion. Therefore, the number of columnar improved bodies can be reduced.

Further, the adjacent columnar improved bodies are connected by the wall-shaped improved body. By reinforcing the adjacent columnar improved bodies with this wall-shaped improved body, the ground subsidence under the embankment and the ground deformation around the embankment are further reduced.

In addition, the embankment is also supported by the wall-shaped improver. This reduces land subsidence between adjacent columnar improvements. Therefore, the distance between adjacent columnar improved bodies can be further increased. Therefore, the number of columnar improved bodies can be further reduced.

The ground improvement structure according to claim 2 is the ground improvement structure according to claim 1, wherein the improvement depth of the overhang improvement portion is from the tip end portion in the overhang direction to the base end portion of the overhang improvement portion. Gradually or gradually deepens.

According to the ground improvement structure according to claim 2, the improvement depth of the overhanging improvement portion gradually or gradually increases from the tip end portion in the overhanging direction to the base end portion of the overhanging improvement portion.

Here, when an embankment load acts on the overhanging improved portion, a bending moment acts on the overhanging improved portion. This bending moment increases from the tip end portion of the overhanging improvement portion in the overhanging direction toward the base end portion (columnar improved body side). Therefore, the base end portion of the overhang improvement portion may be damaged.

On the other hand, in the present invention, the improvement depth of the overhanging improved portion gradually or gradually increases from the tip end portion in the overhanging direction to the base end portion of the overhanging improved portion. As a result, the flexural rigidity of the overhanging improved portion gradually or gradually increases from the tip end portion in the overhanging direction toward the base end portion. Therefore, it is possible to rationally suppress damage to the base end portion of the overhang improvement portion while reducing the improvement range of the overhang improvement portion.

The ground improvement structure according to claim 3 is the ground improvement structure according to claim 1 or 2, wherein the wall-shaped improvement body is provided on an upper portion of adjacent columnar improvement bodies, respectively. Connect the parts.

According to the ground improvement structure according to claim 3, the overhang improvement portion is provided on the upper part of the adjacent columnar improvement body. These overhanging improved parts are connected by a wall-shaped improved body. By reinforcing the adjacent overhanging improved portions with this wall-shaped improved body, the ground subsidence around the overhanging improved portions is further reduced.

The ground improvement structure according to claim 4 is the ground improvement structure according to any one of claims 1 to 3, wherein the wall-shaped improvement body is arranged along the width direction of the embankment.

According to the ground improvement structure according to claim 4, the wall-shaped improvement body is arranged along the width direction of the embankment. As a result, the columnar improved bodies connected by the wall-shaped improved bodies are suppressed from being deformed in the width direction of the embankment. Therefore, the ground deformation on both sides (slope side) of the embankment in the width direction can be efficiently reduced.

The ground improvement structure according to claim 5 includes a plurality of columnar improved bodies formed on the ground supporting the embankment, and the columnar improved bodies formed on the ground and projecting outward from the upper part of the columnar improved body and in the projecting direction. It is provided with an overhanging improvement portion in which the improvement depth gradually or gradually increases from the tip end portion to the base end portion.

According to the ground improvement structure according to claim 5, a columnar improvement body and an overhang improvement portion are formed on the ground supporting the embankment. The overhanging improvement part projects from the upper part of the columnar improved body to the outside. This overhanging improvement section increases the support area of the columnar improvement body that supports the embankment.

Thereby, in the present invention, the distance between the adjacent columnar improved bodies can be widened while reducing the ground subsidence under the embankment and the ground deformation around the embankment as compared with the columnar improved body having no overhanging improved portion. Therefore, the number of columnar improved bodies can be reduced.

Here, when an embankment load acts on the overhanging improved portion, a bending moment acts on the overhanging improved portion. This bending moment increases from the tip end portion of the overhanging improvement portion in the overhanging direction toward the base end portion (columnar improved body side). Therefore, the base end portion of the overhang improvement portion may be damaged.

On the other hand, in the present invention, the improvement depth of the overhanging improved portion gradually or gradually increases from the tip end portion in the overhanging direction to the base end portion of the overhanging improved portion. As a result, the flexural rigidity of the overhanging improved portion gradually or gradually increases from the tip end portion in the overhanging direction toward the base end portion. Therefore, it is possible to rationally suppress damage to the base end portion of the overhang improvement portion while reducing the improvement range of the overhang improvement portion.

As described above, according to the ground improvement structure according to the present invention, the number of columnar improved bodies can be reduced.

FIG. 1 is a sectional view taken along line 1-1 of FIG. 2 showing the ground to which the ground improvement structure according to the embodiment is applied. It is a top view which shows the ground to which the ground improvement structure which concerns on one Embodiment is applied. It is an enlarged view of FIG. 1 which shows a columnar improvement body, an overhang improvement part, and a wall-like improvement body. It is an elevation view which shows the ground improvement apparatus for constructing a columnar improvement body, an overhang improvement part, and a wall-like improvement body shown in FIG. It is a top view which shows the ground improvement apparatus shown in FIG. (A) to (C) are plan views which show the ground to which the modification of the ground improvement structure which concerns on one Embodiment is applied. (A) and (B) are vertical cross-sectional views showing the ground to which the modified example of the ground improvement structure according to one embodiment is applied. It is a vertical cross-sectional view which shows the ground to which the modification of the ground improvement structure which concerns on one Embodiment is applied.

Hereinafter, the ground improvement structure according to the embodiment will be described with reference to the drawings.

(ground)
FIG. 1 shows the ground 10 to which the ground improvement structure 20 according to the present embodiment is applied. The ground 10 contains, for example, clay and silt, and is considered to be a soft ground that easily sinks. An embankment 12 is provided on the ground 10.

(Embankment)
The embankment 12 is used, for example, for roads, railways, embankments, and the like. The cross-sectional shape of the embankment 12 is trapezoidal. The embankment 12 has an upper surface (top surface) 12U and a pair of slopes 12S. The pair of slopes 12S are slopes formed on both sides of the embankment 12 in the width direction. The ground improvement structure 20 according to the present embodiment is applied to the ground 10 under the embankment 12. The cross-sectional shape of the embankment 12 can be changed as appropriate.

(Ground improvement structure)
The ground improvement structure 20 has a plurality of columnar improvement bodies 30, a plurality of overhanging improvement portions 40, and a plurality of wall-shaped improvement bodies 50. The columnar improved body 30, the overhanging improved part 40, and the wall-shaped improved body 50 are excavated with an auger or the like (not shown) for supporting the embankment 12, and the ground 10 is cemented with cement milk or the like. It is formed (created) in the ground 10 by injecting a solidifying material and stirring and mixing the cement-based solidifying material and the excavated soil.

(Columnar improved body)
The columnar improved body (pile-shaped improved body) 30 is formed in a columnar shape, for example. As shown in FIG. 2, the plurality of columnar improved bodies 30 are arranged with intervals C1 and C2 in the width direction (arrow X direction) and the longitudinal direction (arrow Y direction) of the embankment 12. An overhang improvement portion 40 is formed on the upper portion of each columnar improvement body 30.

The columnar improved body 30 may or may not reach the non-consolidated layer (support layer) of the ground 10. Further, the intervals C1 and C2 of the adjacent columnar improved bodies 30 may be the same or different.

(Overhang improvement department)
Overhanging improvement portions 40 are formed on the upper portions of the plurality of columnar improvement bodies 30. The plurality of overhanging improvement portions 40 are arranged with intervals G1 and G2 in the longitudinal direction and the width direction of the embankment 12.

As shown in FIG. 3, the overhang improvement portion 40 is formed by improving the ground around the upper portion of the columnar improvement body 30. The overhanging improvement portion 40 projects outward (sideways) from the upper part of the columnar improving body 30. More specifically, the overhanging improvement unit 40 projects outward from the upper part of the columnar improving body 30 over the entire circumference of the columnar improving body 30. Further, the overhang improving portion 40 is formed in a circular shape in a plan view. Further, the overhang improving portion 40 is formed in a hemispherical shape forming a convex shape downward from the ground surface 10U of the ground 10. The embankment 12 is supported by the circular upper surface 40U of the overhanging improvement portion 40.

The improvement depth D of the overhang improvement portion 40 gradually becomes deeper from the tip portion 40A in the overhang direction of the overhang improvement portion 40 toward the base end portion 40B. As a result, the lower surface 40L of the overhanging improvement portion 40 has a spherical shape. Further, the bending rigidity (flexural rigidity in the vertical direction) of the overhanging improved portion 40 gradually increases from the tip portion 40A in the overhanging direction toward the base end portion 40B. As a result, damage to the base end portion 40B side of the overhang improvement portion 40 is suppressed.

Here, the intervals G1 and G2 of the adjacent overhanging improvement portions 40 are appropriately set in consideration of, for example, the arch effect generated in the embankment 12. That is, an arch portion 14 is formed in the embankment 12 as the unimproved region 10V (see FIG. 2) of the ground 10 sinks. The arch portion 14 is formed over a plurality of overhanging improved portions 40 surrounding the unimproved region 10V. The embankment load F on the arch portion 14 acts in a dispersed manner on the plurality of overhanging improvement portions 40 along the arch portion 14. Therefore, the amount of subsidence in the unimproved region 10V is reduced.

On the other hand, when the distances G1 and G2 between the adjacent overhanging improved portions 40 are widened, the embankment load acting on the unimproved region 10V from the arch portion 14 increases, and the subsidence amount of the unimproved region 10V increases. Therefore, for example, the intervals G1 and G2 of the adjacent overhanging improvement portions 40 are set so that the subsidence amount of the unimproved region 10V is equal to or less than a predetermined value.

The intervals G1 and G2 of the adjacent overhanging improvement portions 40 may be the same or different.

(Wall-shaped improved body)
As shown in FIGS. 1, 2, and 3, the columnar improved bodies 30 adjacent to each other in the width direction of the embankment 12 are connected by the wall-shaped improved body 50, respectively. The wall-shaped improved body 50 is formed by improving the ground 10 between the columnar improved bodies 30 adjacent to each other in the width direction of the embankment 12 into a wall shape.

As shown in FIG. 3, the wall-shaped improved body 50 extends in the width direction of the embankment 12 and extends over the adjacent columnar improved bodies 30. Further, the wall-shaped improved body 50 is formed from the ground surface 10U of the ground 10 to the intermediate portion of the columnar improved body 30 in the material axial direction. The upper portion of the wall-shaped improved body 50 connects adjacent overhanging improved portions 40. On the other hand, the lower portion of the wall-shaped improved body 50 is below the overhanging improved portion 40 and connects the adjacent columnar improved bodies 30.

The lower end portion 50E of the wall-shaped improved body 50 is arranged below the lower surface 40L of the overhanging improved body 40 and above the lower end portion 30E (see FIG. 1) of the columnar improved body 30. That is, in the present embodiment, the improvement depth of the wall-shaped improvement body 50 is deeper than the improvement depth D of the overhanging improvement portion 40 and shallower than the improvement depth of the columnar improvement body 30.

(Construction method of ground improvement structure)
Next, an example of the construction method of the ground improvement structure 20 according to the present embodiment will be described.

As shown in FIG. 4, first, the overhang improvement portion 40 is formed on the ground 10 by the ground improvement device 60. The ground improvement device 60 includes a rod 62, a rotary biaxial hinge 64, and a swivel auger 66.

The rod 62 is attached to a backhoe or the like (not shown) along the vertical direction. One end of the swivel auger 66 is attached to the lower end of the rod 62 via a rotary biaxial hinge 64. The rotary biaxial hinge 64 has a swivel shaft R1 extending in the lateral direction (horizontal direction) and a rotary shaft R2 (see FIG. 5) extending in the vertical direction.

The swivel auger 66 can excavate the ground 10 by rotating around a rotation shaft P extending in the axial direction of the swivel auger 66. Further, the swivel auger 66 can swivel around the swivel shaft R1 of the rotary biaxial hinge 64. As a result, the swivel auger 66 is capable of excavating the ground 10 in a fan shape (including a semicircular shape) when viewed from the axial direction of the swivel shaft R1.

Further, as shown in FIG. 5, the swivel auger 66 rotates about the rotation axis R2 so that the ground 10 can be excavated in a circular shape in a plan view. Further, the ground 10 can be excavated in a hemispherical shape by rotating the swivel auger 66 around the two axes of the swivel shaft R1 and the rotary shaft R2.

An injection hole (not shown) for injecting a cement-based solidifying material such as cement milk is formed at the tip of the swirling auger 66. Then, while excavating the ground 10 in a hemispherical shape by the swirling auger 66, a cement-based solidifying material is injected into the ground 10 from the tip of the swirling auger 66, and the ground 10 and the cement-based solidifying material are stirred and mixed to overhang. The improved portion 40 is formed on the ground 10.

Next, as shown in FIG. 4, the rod 62 and the swivel auger 66 are arranged in a straight line, and the ground 10 below the central portion of the overhang improvement portion 40 is further excavated in a plan view. At this time, the cement-based solidifying material is injected into the ground 10 from the tip of the swirling auger 66, and the ground 10 and the cement-based solidifying material are stirred and mixed to form the columnar improved body 30.

When constructing the columnar improved body 30 and the overhanging improved portion 40, the regions T1 and T3 (see FIG. 3) of the wall-shaped improved body 50 are also constructed. Specifically, the regions T1 and T3 are excavated with the rod 62 and the swivel auger 66 arranged on a straight line. At this time, the cement-based solidifying material is injected into the ground 10 from the tip of the swirling auger 66, and the ground 10 and the cement-based solidifying material are stirred and mixed to form the regions T1 and T3 of the wall-shaped improved body 50 in order. ..

Next, the region T2 (see FIG. 3) of the wall-shaped improved body 50 is constructed in the same manner as the regions T1 and T3.

By repeating the above procedure, a plurality of columnar improved bodies 30, an overhanging improved portion 40, and a wall-shaped improved body 50 are formed.

The construction procedure of the ground improvement structure 20 can be changed as appropriate. For example, the columnar improved body 30 may be formed first, and then the overhanging improved portion 40 may be formed.

(Action)
Next, the operation of this embodiment will be described.

As shown in FIGS. 1 and 2, according to the ground improvement structure 20 according to the present embodiment, the ground 10 supporting the embankment 12 includes a plurality of columnar improvement bodies 30, a plurality of overhanging improvement portions 40, and a plurality of overhanging improvement portions 40. A plurality of wall-shaped improved bodies 50 are formed. By increasing the rigidity of the ground 10 that supports the embankment 12 by the columnar improved body 30, the overhanging improved portion 40, and the plurality of wall-shaped improved bodies 50, the ground subsidence under the embankment 12 and the ground deformation around the embankment 12 Is reduced.

Further, the overhang improvement section 40 is provided on each of the upper portions of the plurality of columnar improvement bodies 30. Each overhanging improvement portion 40 projects outward from the upper part of the columnar improving body 30 over the entire circumference of the columnar improving body 30. These overhanging improvement portions 40 increase the supporting area of the columnar improving body 30 that supports the embankment 12.

As a result, in the present embodiment, as compared with the columnar improved body 30 having no overhanging improved portion, the distance between adjacent columnar improved bodies 30 is reduced while reducing the ground subsidence under the embankment 12 and the ground deformation around the embankment 12. C1 and C2 (see FIG. 2) can be expanded. Therefore, the number of columnar improved bodies 30 can be reduced.

Further, in the present embodiment, the intervals G1 and G2 of the adjacent overhanging improvement portions 40 are set in consideration of the arch effect generated in the embankment 12. As a result, in the present embodiment, as compared with the case where the arch effect generated in the embankment 12 is not taken into consideration, the distance between the adjacent overhanging improved portions 40 G1 and G2, while reducing the subsidence amount of the unimproved region 10V, That is, the intervals C1 and C2 of the adjacent columnar improved bodies 30 can be widened. Therefore, the number of columnar improved bodies 30 can be further reduced.

Further, the adjacent columnar improved bodies 30 are connected by a wall-shaped improved body 50. Further, the adjacent overhanging improvement portions 40 are connected by a wall-shaped improving body 50. By reinforcing the adjacent columnar improved body 30 and the adjacent overhanging improved portion 40 by the wall-shaped improved body 50, the ground subsidence of the ground 10 under the embankment 12 and the ground deformation around the embankment 12 are further reduced. To.

Further, the wall-shaped improved body 50 is arranged along the width direction of the embankment 12, and the adjacent columnar improved body 30 and the adjacent overhanging improved portion 40 are connected in the width direction of the embankment 12. As a result, the columnar improved body 30 and the overhanging improved portion 40 are suppressed from being deformed (laterally deformed) in the width direction of the embankment 12. Therefore, the ground deformation on both sides of the embankment 12 in the width direction (slope 12S side) is further reduced.

Further, in the present embodiment, the embankment 12 is also supported by the wall-shaped improved body 50. As a result, the ground subsidence between the adjacent columnar improved bodies 30 is further reduced. Therefore, the intervals C1 and C2 of the adjacent columnar improved bodies 30 can be further widened. Therefore, the number of columnar improved bodies 30 can be further reduced.

Here, when an embankment load acts on the overhang improving portion 40, a bending moment acts on the overhang improving portion 40. This bending moment increases from the tip portion 40A in the overhanging direction of the overhanging improved portion 40 toward the base end portion 40B (columnar improved body 30 side). Therefore, the base end portion 40B of the overhanging improvement portion 40 may be damaged.

On the other hand, the overhang improvement portion 40 of the present embodiment is formed in a hemispherical shape that is convex downward from the ground surface 10U of the ground 10. That is, the improvement depth D of the overhang improvement portion 40 gradually becomes deeper from the tip portion 40A in the overhang direction of the overhang improvement portion 40 toward the base end portion 40B. As a result, the flexural rigidity of the overhanging improved portion 40 gradually increases from the tip portion 40A in the overhanging direction of the overhanging improved portion 40 toward the base end portion 40B. Therefore, in the present embodiment, it is possible to rationally suppress damage to the base end portion 40B of the overhang improving portion 40 while reducing the improvement range of the overhang improving portion 40.

(Modification example)
Next, a modified example of the above embodiment will be described.

In the above embodiment, the adjacent columnar improved body 30 and the adjacent overhanging improved portion 40 are connected by the wall-shaped improved body 50, respectively. However, the wall-shaped improved body 50 can connect at least one of the adjacent columnar improved body 30 and the adjacent overhanging improved portion 40.

Further, in the above embodiment, the improvement depth of the wall-shaped improved body 50 is deeper than that of the overhanging improved portion 40 and shallower than that of the columnar improved body 30. However, the improvement depth of the wall-shaped improved body may be, for example, the same as that of the overhanging improved portion 40, or may be shallower than that of the overhanging improved portion 40. Further, the improvement depth of the wall-shaped improved body 50 may be the same as that of the columnar improved body 30, or may be deeper than that of the columnar improved body 30.

Further, in the above embodiment, the wall-shaped improved body 50 is arranged along the width direction of the embankment 12. However, for example, as in the modified example shown in FIG. 6A, the wall-shaped improved body 52 is arranged along the longitudinal direction of the embankment 12, and the columnar improved body 30 adjacent to the embankment 12 in the longitudinal direction and the embankment The overhanging improvement portions 40 adjacent to each other in the longitudinal direction of the 12 may be connected.

Further, for example, as in the modified example shown in FIG. 6B, the wall-shaped improved body 54 is arranged along the inclined direction inclined with respect to the width direction and the longitudinal direction of the embankment 12, and is adjacent to the inclined direction. The matching columnar improved body 30 and the overhanging improved portions 40 adjacent to each other in the inclination direction may be connected.

Further, the number of the wall-shaped improved bodies 50 can be changed as appropriate, and at least one wall-shaped improved body 50 can be formed on the ground 10. It is desirable that the wall-shaped improved body 50 is provided at the central portion in the width direction of the embankment 12 where the embankment load tends to be large.

Further, in the above embodiment, a plurality of columnar improved bodies 30 are arranged in the width direction and the longitudinal direction of the embankment 12. However, the arrangement and number of columnar improved bodies 30 can be changed as appropriate. For example, as in the modified example shown in FIG. 6C, the plurality of columnar improved bodies 30 may be arranged in a staggered manner in a plan view. In the modified example shown in FIG. 6C, the wall-shaped improved body 54 is arranged along the inclination direction.

Further, in the above embodiment, the improvement depth D (see FIG. 3) of the overhang improvement portion 40 gradually becomes deeper from the tip portion 40A in the overhang direction of the overhang improvement portion 40 toward the base end portion 40B. .. However, for example, as in the modified example shown in FIG. 7A, the improvement depth D of the overhang improvement portion 42 is from the tip portion 42A in the overhang direction of the overhang improvement portion 42 toward the base end portion 42B. It may be deepened step by step. Further, for example, as in the modified example shown in FIG. 7B, the improvement depth of the overhanging improvement unit 44 can be made substantially constant.

Further, in the above embodiment, the overhang improving portion 40 is formed in a circular shape in a plan view. However, the overhanging improved portion may be formed in a rectangular shape or a polygonal shape in a plan view, for example. Further, in the above embodiment, the overhanging improvement portion 40 projects outward from the upper part of the columnar improving body 30 over the entire circumference. However, the overhanging improvement portion may partially overhang from the upper part of the columnar improving body 30 to the outside in a predetermined direction, for example.

Further, in the above embodiment, the adjacent columnar improved bodies 30 are connected by the wall-shaped improved body 50. However, it is also possible to omit the wall-shaped improved body, for example, as in the modified example shown in FIG.

As described above, the bending moment acts on the overhang improving portion 40. However, in the modified example shown in FIG. 8, the overhanging improving portion 40 is stretched because the adjacent overhanging improving portions 40 are not connected by the wall-shaped improving body. Deformation of the output improvement unit 40 tends to be large. Therefore, when the adjacent overhang improvement portions 40 are omitted, the improvement depth D of the overhang improvement portion 40 is gradually or gradually increased from the tip portion 40A in the overhang direction toward the base end portion 40B. Is desirable.

Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and one embodiment and various modifications may be used in combination as appropriate. Of course, it can be carried out in various modes as long as it does not deviate.

10 Ground 12 Embankment 20 Ground improvement structure 30 Columnar improvement body 40 Overhang improvement part 40A Overhang improvement part tip 40B Overhang improvement part extension direction base end 42 Overhang improvement part 42A Overhang Tip part in the overhang direction of the improved part 42B Base end part in the overhang direction of the overhanging improved part 44 Overhanging improved part 50 Wall-shaped improved body 52 Wall-shaped improved body 54 Wall-shaped improved body D Improvement depth of the overhanging improved part X Width direction of embankment

The ground improvement structure according to the first aspect includes a plurality of columnar improvement bodies formed on the ground supporting the embankment, an overhanging improvement portion formed on the ground and projecting outward from the upper part of the columnar improvement body, and the above-mentioned It is provided with a wall-shaped improved body formed on the ground and connecting adjacent columnar improved bodies.

According to the ground improvement structure according to the first aspect , a columnar improvement body, an overhang improvement part, and a wall-like improvement body are formed on the ground supporting the embankment. The overhanging improvement part projects from the upper part of the columnar improved body to the outside. This overhanging improvement section increases the support area of the columnar improvement body that supports the embankment. Thereby, in the present invention, the distance between the adjacent columnar improved bodies can be widened while reducing the ground subsidence under the embankment and the ground deformation around the embankment as compared with the columnar improved body having no overhanging improved portion. Therefore, the number of columnar improved bodies can be reduced.

The ground improvement structure according to the second aspect is the ground improvement structure according to the first aspect, in which the improvement depth of the overhang improvement portion is gradually increased from the tip end portion in the overhang direction to the base end portion of the overhang improvement portion. Or gradually deepen.

According to the ground improvement structure according to the second aspect , the improvement depth of the overhanging improvement portion gradually or gradually increases from the tip end portion in the overhanging direction to the base end portion of the overhanging improvement portion.

The ground improvement structure according to the third aspect is the ground improvement structure according to the first aspect or the second aspect , and the wall-shaped improvement body has the overhanging improvement portion provided on the upper part of the adjacent columnar improvement body. Link.

According to the ground improvement structure according to the third aspect , the overhang improvement portion is provided on the upper part of the adjacent columnar improvement body. These overhanging improved parts are connected by a wall-shaped improved body. By reinforcing the adjacent overhanging improved portions with this wall-shaped improved body, the ground subsidence around the overhanging improved portions is further reduced.

Ground improvement structure according to the fourth aspect, the ground improvement structure according to any one of the first aspect to third aspect, the wall-like improved body is disposed along the width direction of the embankment.

According to the ground improvement structure according to the fourth aspect , the wall-shaped improvement body is arranged along the width direction of the embankment. As a result, the columnar improved bodies connected by the wall-shaped improved bodies are suppressed from being deformed in the width direction of the embankment. Therefore, the ground deformation on both sides (slope side) of the embankment in the width direction can be efficiently reduced.

The ground improvement structure according to the fifth aspect includes a plurality of columnar improved bodies formed on the ground supporting the embankment, and the columnar improved bodies formed on the ground and projecting outward from the upper part of the columnar improved body and at the tip in the projecting direction. It is provided with an overhanging improvement portion in which the improvement depth gradually or gradually increases from the portion to the base end portion.

According to the ground improvement structure according to the fifth aspect , a columnar improvement body and an overhang improvement portion are formed on the ground supporting the embankment. The overhanging improvement part projects from the upper part of the columnar improved body to the outside. This overhanging improvement section increases the support area of the columnar improvement body that supports the embankment.

Claims (5)

Multiple columnar improved bodies formed on the ground supporting the embankment,
An overhanging improvement portion formed on the ground and projecting outward from the upper part of the columnar improvement body,
A wall-shaped improved body formed on the ground and connecting adjacent columnar improved bodies,
Ground improvement structure equipped with. The improvement depth of the overhang improvement portion gradually or gradually increases from the tip end portion in the overhang direction to the base end portion of the overhang improvement portion.
The ground improvement structure according to claim 1. The wall-shaped improved body connects the overhanging improved portions provided on the upper portions of the adjacent columnar improved bodies.
The ground improvement structure according to claim 1 or 2. The wall-shaped improved body is arranged along the width direction of the embankment.
The ground improvement structure according to any one of claims 1 to 3. Multiple columnar improved bodies formed on the ground supporting the embankment,
An overhanging improved portion formed on the ground and extending outward from the upper part of the columnar improved body, and the improvement depth gradually or gradually increases from the tip end portion to the base end portion in the overhanging direction.
Ground improvement structure equipped with.

Images