JP2007046399A - Earth retaining wall of double structure, its construction method, and horizontal multi-spindle rotary soil improvement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double structure earth retaining wall by a soil cement wall constructed on the outer periphery of a ground to be excavated. <P>SOLUTION: This earth retaining wall is formed as an improved double structure body comprising a layer with a design strength at the rear side and a layer with a low strength on the excavated side when viewed from above. Core materials are constructed in the improved body at approximately equal intervals. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to the technical field of a mountain retaining wall by a soil cement wall having a two-layer structure constructed on the outer periphery of the ground to be excavated, a construction method thereof, and a horizontal multi-axis rotation type ground improvement device. Two-layer structure retaining wall in which a core material is built in a two-layer structure improvement body of a layer having a design strength and a layer having a low strength on the excavation side, and a construction method thereof, and a horizontal multi-axis rotation type ground improvement device About.

  2. Description of the Related Art Conventionally, a technique for constructing a retaining wall by a soil cement wall and excavating the ground in the retaining wall to construct, for example, an underground frame has been widely implemented. At this time, while excavating the ground in the retaining wall, the soil cement on the excavation side is removed from the core material of the retaining wall to expose the concentric material, and the underground frame is integrated so as to be integrated with the exposed core material. Often the side walls are constructed into a synthetic basement wall, but the usual retaining wall has a core built in an improvement made of soil cement of equal strength (ie, an improvement of equal strength in all areas) It is a structure, and it has a great labor at the time of the turning work which removes the soil cement by the side of excavation from the core material of a retaining wall. However, there is no effective way.

  In other words, in the past, it was not possible to observe the mountain retaining wall with a configuration that can reduce the above-mentioned turning work, and of course, a two-layer structure improvement body of a layer having a design strength on the back side and a layer having a low strength on the excavation side. The two-layered retaining wall with the core material built in cannot be seen. Therefore, it is not possible to observe the construction method of the two-layer structure retaining wall and the horizontal multi-axis rotating ground improvement device used for constructing the retaining wall.

By the way, although a two-layer mountain retaining wall cannot be constructed, it has a cement milk jet at the tip of the head and the position above the stirring blade, from the jet at the tip during excavation, and above the stirring blade during lifting A ground improvement device having a configuration in which cement milk is ejected from a spout at a position is known (Patent Document 1).
JP 2002-30650 A

  An object of the present invention is to have a structure in which a core material is built in a two-layer structure improvement body of a layer having a design strength on the back side and a layer having a low strength on the excavation side, and has a two-layer structure that is easy to beat. A mountain retaining wall, a construction method thereof, and a horizontal multi-axis rotation type ground improvement device.

As a means for solving the problems of the prior art, a two-layer structure retaining wall according to the invention described in claim 1 is:
It is a mountain retaining wall with a soil cement wall constructed on the outer periphery of the ground to be excavated,
The mountain retaining wall is formed as a two-layer structure improvement body with a layer having a design strength on the back side and a layer having a low strength on the excavation side in plan view, and the core material is built on the improvement body at substantially equal intervals. It is characterized by being included.

The construction method of the mountain retaining wall of the two-layer structure according to the invention described in claim 2
A method of constructing a retaining wall by a soil cement wall constructed on the outer periphery of the ground to be excavated,
The retaining wall is formed as a two-layer structure improvement body consisting of a layer having the design strength on the back side and a layer having a low strength on the excavation side in plan view, and the core material is built on the improvement body at substantially equal intervals. It is characterized by being built in.

Invention of Claim 3 is the construction method of the mountain retaining wall of the two-layer structure described in Claim 2,
In plan view, a horizontal multi-axis rotating ground improvement device that has at least one cement milk spout on the back side and excavation side of the retaining wall is used, and the design strength is met from the back spout. Cement milk blended with the above cement is jetted out, and the cement milk with a small amount of cement blended out from the jetting outlet on the excavation side is mixed and stirred with the excavated soil to form a two-layer structure improvement body. And

A horizontal multi-axis rotary ground improvement device according to the invention described in claim 4 is:
In a horizontal multi-axis rotary ground improvement device having a head portion equipped with a horizontal rotary cutter wheel,
Cement milk spouts are arranged on the back side and excavation side of the retaining wall in the cutter wheel,
The structure is characterized in that cement milk mixed with an amount of cement that satisfies the design strength is ejected from the jet port on the back side, and cement milk with a small amount of cement is jetted from the jet port on the excavation side. .

A horizontal multi-axis rotary ground improvement device according to the invention described in claim 5 is:
In a horizontal multi-axis rotary ground improvement device having a head portion equipped with a horizontal rotary cutter wheel,
The head part consists of a unit part on the back side and a unit part on the excavation side, and each unit part has two sets of cutter wheels arranged in the direction of excavation, and a cement milk jet is arranged at the approximate center position. Being
Cement milk containing a sufficient amount of cement that satisfies the design strength is ejected from the rear unit outlet, and cement milk with less cement is injected from the drilling unit outlet. It is characterized by being.

A sixth aspect of the present invention is the horizontal multi-axis rotation type ground improvement device according to the fifth aspect,
Cement milk spouts are also located on both the back side and the excavation side of the retaining wall of the cutter wheel. Cement milk containing an amount of cement that satisfies the design strength is ejected from the back side spout. The cement milk having a small amount of cement is ejected from the excavation-side jet outlet.

  The two-layered mountain retaining wall and the construction method thereof according to the present invention have a configuration in which a core material is built in a two-layer structure improved body of a layer having a design strength on the back side and a layer having a low strength on the excavation side. Therefore, excavation of the excavation ground in the retaining wall and removal of soil cement on the excavation side from the core material of the retaining wall is easy, the workability is dramatically improved, and the construction period is greatly shortened. it can.

  Since the horizontal multi-axis rotation type ground improvement device according to the present invention has a configuration capable of ejecting cement milk having different cement blending amounts, a two-layer structure improvement body can be easily and reliably constructed.

  The mountain retaining wall is formed as a two-layer structure improvement body with a layer having a design strength on the back side and a layer having a low strength on the excavation side in plan view, and the core material is built on the improvement body at substantially equal intervals. Is included.

  In the following, the two-layer structure retaining wall according to the invention described in claim 1, the method for constructing the two-layer structure retaining wall according to the invention described in claims 2 and 3, and the invention described in claim 4 An embodiment of such a horizontal multi-axis rotation type ground improvement device will be described with reference to the drawings.

  The two-layer structure retaining wall 1 of the present invention has a configuration similar to that of a conventional soil cement wall retaining wall. However, as shown in FIG. 1 and FIG. The two-layer structure improvement body 5 of the layer 3 having the design strength on the back side (that is, the strength that can sufficiently withstand the earth pressure on the back side) and the layer 4 having the low strength on the excavation side is formed. A core material 6 made of H-shaped steel (however, square steel pipe, round steel pipe, I-shaped steel, etc.) may be built at substantially equal intervals (the invention according to claim 1). Therefore, the excavation ground 2 in the retaining wall 1 is excavated, and the excavation side soil cement 4a is easily removed from the core material 6 of the retaining wall 1, and the workability is greatly improved. The period can be greatly shortened. It should be noted that the strength of the layer 4 having a low strength on the excavation side is set in consideration of the workability of the turning work.

The mountain retaining wall 1 having the above-described configuration is constructed using, for example, the following horizontal multi-axis rotating ground improvement device 7.
The ground improvement device 7 has substantially the same configuration as a conventional horizontal multi-axis rotation type ground improvement device. That is, as shown in FIG. 3, the top end of the rail 9 is supported on the top of the leader 8, and the kelly bar 10 that moves along the rail 9 is suspended. A head portion 11 is connected to the lower end portion of the kelly bar 10, and the head portion 11 is composed of two sets of cutter wheels 12 and 12 arranged in parallel on the back side and the excavation side as shown in FIG. The groups 13 and 13 are rotatably supported by the lower end part of the casing 14 in the form arranged in the excavation direction. Each set of cutter wheel groups 13 and 13 is configured to be rotationally driven by driving means 15 and 15, respectively.

  However, as shown in FIG. 5 and FIG. 6, cement milk jets 16 and 17 are arranged on both the back side and the excavation side of the head portion 11 (that is, the cutter wheel group 13). The jets 16 and 17 are connected to different plants 18 and 19. The plant 18 stores cement milk containing an amount of cement that satisfies the design strength, and the cement milk is supplied from the plant 18 to the jet port 16 on the back side through the grout hose 20. The plant 19 stores cement milk having a smaller blending amount of cement than cement milk ejected from the rear-side jet nozzle 16, and the cement milk is sprayed from the plant 19 via the grout hose 21 on the excavation side. It is supplied to the outlet 17 (the invention according to claim 4).

  Using the ground improvement device 7 having the above-described configuration, as shown in FIG. 7, cement milk mixed with an amount of cement satisfying the design strength is ejected from the rear-side jet nozzle 16, and from the excavation-side jet nozzle 17. A layer 3 having a design strength on the back side is formed around the excavated ground 2 by jetting cement milk having a smaller blending amount of cement than the cement milk jetted from the jet port on the back side and mixing and agitating each with the excavated soil. When the two-layer structure improvement body 5 with the layer 4 having low strength on the excavation side is formed, and the core material 6 is installed in the improvement body 5 at substantially equal intervals, the construction of the retaining wall 1 is completed. 3). Since the mountain retaining wall 1 is constructed using the ground improvement device 7 capable of jetting cement milk having different cement blending amounts, the two-layer structure improvement body 5 can be easily and reliably constructed.

  As shown in FIGS. 8 and 9, the mountain retaining wall 1 of the present embodiment is joined to the core member 6 exposed by the further bending operation, and the stud 22 is joined to the side wall 23 a of the underground frame 23 to form a synthetic underground wall. 24 is formed. As described above, since the turning work is easy, it is possible to quickly shift to the construction of the underground frame 23, which can also contribute to a significant shortening of the construction period.

  A ground improvement device 25 shown in FIG. 10 has a head portion 26 connected to the lower end portion of the kelly bar 10 as in the ground improvement device 7 shown in FIG. 3, but the configuration of the head portion 26 is different. Incidentally, although not shown in the drawing, the kelly bar 10 stores a grout hose connected to the plant 18 (referring to FIG. 6A) and a grout hose connected to the plant 19.

  The head portion 26 has a configuration in which a unit portion 27a on the back side and a unit portion 27b on the excavation side are arranged in parallel and integrated, and each unit portion 27a, 27b is supported by the kelly bar 10.

  As shown in FIG. 11, the unit portion 27a (27b) includes two sets of cutter wheel groups 13 and 13 including cutter wheels 12 and 12 arranged in parallel on the back side and the excavation side. Is supported at the lower end of the casing 14 in a rotatable manner, and in the wall thickness direction is a position between the cutter wheels 12 and 12 arranged in parallel on the excavation side and the back side, and in the excavation direction Has a cement milk spout 28a (28b) at a position between the two sets of cutter wheels 13 and 13 (that is, at a substantially central position). And although illustration is abbreviate | omitted, the spout 28a of the unit part 27a of the back side is connected with the grout hose connected to the plant 18, and spouts the cement milk which mix | blended the quantity of the cement which satisfy | fills design strength. It is a configuration. The jet outlet 28b of the excavation side unit portion 27b is connected to a grout hose connected to the plant 19, and jets cement milk having a smaller amount of cement than cement milk jetted from the rear jet nozzle 28a. It is a structure (invention of Claim 5). That is, it is the structure which arranged the head part of the usual horizontal multi-axis rotation type ground improvement apparatus in parallel on the back side and the excavation side. Since the ground improvement device 25 having the above-described configuration is also a configuration capable of ejecting cement milk having different cement blending amounts, the two-layer structure improvement body 5 can be easily and reliably constructed. In addition, a thick improvement body 5 can be formed.

  Incidentally, as shown in FIGS. 10 and 11, cement milk jets 29 and 30 are arranged on both the rear side and the outer side of the excavation side in the head portion 26 (that is, the cutter wheel groups 13 and 13). A cement milk mixed with an amount of cement having a design strength is ejected from the jet nozzle 29 on the side, and the blending amount of cement is larger than the cement milk jetted from the jet nozzle 29 on the back side from the jet nozzle 30 on the excavation side. A configuration in which a small amount of cement milk is ejected is advantageous because a large amount of cement milk can be ejected (the invention according to claim 6).

  In short, the ground improvement device for forming the improvement body 5 having a two-layer structure may be any structure as long as it has at least one jet of cement milk on the back side and the excavation side. For example, the above ground improvement device 7 (25). Is a configuration in which the cutter wheels 12, 12 are arranged in parallel on the back side and the excavation side, but the number is not particularly limited.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments and can be implemented in various forms without departing from the gist of the present invention.

It is the longitudinal cross-sectional view which showed the Example of the mountain retaining wall of the two-layer structure which concerns on this invention. It is the top view which showed the Example of the mountain retaining wall of the two-layer structure which concerns on this invention. It is the elevation which showed the example of the horizontal multi-axis rotation type ground improvement device concerning the present invention. It is a structural view showing a head part. (A) is the perspective view which showed the head part roughly. (B) is a bottom view. (A) is the top view which showed roughly the connection relation of a ground improvement apparatus and a plant. (B) is a front view. It is the construction figure which showed schematically the Example of the construction method of the mountain retaining wall of the two-layer structure which concerns on this invention. It is the longitudinal cross-sectional view which showed the Example which integrated the side wall of the underground frame with the mountain retaining wall of the two-layer structure which concerns on this invention, and was set as the synthetic underground wall. It is a partial horizontal sectional view of FIG. It is the elevation which showed the different Example of the horizontal multi-axis rotation type ground improvement apparatus which concerns on this invention. (A) is the perspective view which showed the head part roughly. (B) is a bottom view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Double-layered retaining wall 2 Excavation ground 3 Layer with design strength on the back side 4 Low-strength layer on excavation side 5 Double-layer structure improvement body 6 Core material 7 Horizontal multi-axis rotation type ground improvement device 11 Head part 12 Cutter wheel 16 Cement milk spout 17 Cement milk spout 25 Horizontal multi-axis rotary ground improvement device 26 Head part 27a, 27b Unit part 28a, 28b Cement milk spout 29 Cement milk spout 30 Cement milk spout 30 Spout

Claims (6)

It is a mountain retaining wall with a soil cement wall constructed on the outer periphery of the ground to be excavated,
The mountain retaining wall is formed as a two-layer structure improvement body with a layer having a design strength on the back side and a layer having a low strength on the excavation side in plan view, and the core material is built on the improvement body at substantially equal intervals. A double-layered mountain retaining wall characterized by being embedded. A method of constructing a retaining wall by a soil cement wall constructed on the outer periphery of the ground to be excavated,
The retaining wall is formed as a two-layer structure improvement body consisting of a layer having the design strength on the back side and a layer having a low strength on the excavation side in plan view, and the core material is built on the improvement body at substantially equal intervals. A method for constructing a two-layer mountain retaining wall, characterized by comprising   In plan view, use a horizontal multi-axis rotating ground improvement device that has at least one cement milk spout on the back side and excavation side of the retaining wall, and the amount that satisfies the design strength from the back spout Cement milk blended with the above cement is jetted out, and the cement milk with a small amount of cement blended out from the jetting outlet on the excavation side is mixed and stirred with the excavated soil to form a two-layer structure improvement body. The method for constructing a mountain retaining wall having a two-layer structure according to claim 2. In a horizontal multi-axis rotary ground improvement device having a head portion equipped with a horizontal rotary cutter wheel,
Cement milk spouts are arranged on the back side and excavation side of the retaining wall in the cutter wheel,
The structure is characterized in that cement milk mixed with an amount of cement that satisfies the design strength is ejected from the jet port on the back side, and cement milk with a small amount of cement is jetted from the jet port on the excavation side. , Horizontal multi-axis rotation type ground improvement device. In a horizontal multi-axis rotary ground improvement device having a head portion equipped with a horizontal rotary cutter wheel,
The head part consists of a unit part on the back side and a unit part on the excavation side, and each unit part has two sets of cutter wheels arranged in the direction of excavation, and a cement milk jet is arranged at the approximate center position. Being
Cement milk containing a sufficient amount of cement that satisfies the design strength is ejected from the rear unit outlet, and cement milk with less cement is injected from the drilling unit outlet. A horizontal multi-axis rotary ground improvement device, characterized in that there is.   Cement milk spouts are also located on both the back side and the excavation side of the retaining wall of the cutter wheel. Cement milk containing an amount of cement that satisfies the design strength is ejected from the back side spout. 6. The horizontal multi-axis rotating ground improvement device according to claim 5, wherein cement milk with a small amount of cement is jetted from a jetting port on the excavation side.

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