Core material for earth retaining wall, earth retaining wall and construction method thereof

Abstract

To provide a core material for an earth retaining wall which can be smoothly and accurately erected inside soil cement having a large penetration resistance, an earth retaining wall provided with the core material for the earth retaining wall, and a method for constructing thereof.SOLUTION: The present invention relates to a core material 40 for an earth retaining wall, which is applied when constructing a soil cement column series continuous wall 60 that is an earth retaining wall. The core material 10 has a suction tube 30 extending in its longitudinal direction, and when the core material 10 is inserted into soil cement 50, the soil cement 50 ahead in an insertion direction is sucked through the suction tube 30.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a core material for an earth retaining wall, an earth retaining wall, and a construction method thereof. [Background technology]

[0002] Retaining walls include prefabricated sheet pile walls such as horizontal sheet pile walls and steel sheet pile walls, and cast-in-place walls such as column-row walls and continuous underground walls. Column-row walls include cast-in-place reinforced concrete column-row walls, steel pipe column-row walls, and soil cement column-row walls (soil cement column-row continuous walls).

[0003] For example, while the above-mentioned soil cement continuous column wall is a temporary structure, there is also a form in which the soil cement continuous column wall is used as part of the foundation of a permanent building by connecting it to the side walls of the underground part of a permanent building.

[0004] A soil cement diaphragm wall is constructed by wrapping cylindrical soil cement around each other, with a core material made of H-shaped steel or the like buried inside each soil cement. One way to connect this soil cement diaphragm wall to the permanent structure is to remove the upper area of ​​the soil cement facing the permanent structure to expose part of the core material, weld multiple stud dowels or the like to the exposed part of the core material so that it protrudes to the side, and then construct the underground side walls of the permanent structure in the ground with each stud dowel or the like buried, thereby integrating the two.

[0005] In the construction of the above-mentioned soil cement diaphragm wall, when inserting and erecting the core material into the soil cement created in the ground, there is a problem that the viscous soil cement acts on the core material with a large penetration resistance, making it difficult to erect the core material with precision. Therefore, there is a need for a construction method for core material and earth retaining wall that can erect the core material into the soil cement smoothly and with high precision.

[0006] Here, Patent Document 1 proposes a core material for an earth retaining wall made of H-shaped steel, in which at least one flange side of the tip does not have a flange and the tip is composed of only a web, and the side end face of the web at the tip without a flange is inclined inward toward the end, and the web width at the tip is narrowed so that it tapers. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-11695 Summary of the Invention [Problem to be solved by the invention]

[0008] According to the core material for earth retaining walls described in Patent Document 1, the web width at the tip of the core material is narrowed so that it tapers, so that even if the tip of the core material comes into contact with the groove wall surface, it will not bite into it and will be able to enter along the groove wall surface, making insertion easy. However, since the presence of soil cement, which acts as penetration resistance, remains, it is unclear whether simply tapering the web will allow the core material to be erected smoothly and with high precision.

[0009] The present invention has been made in view of the above-mentioned problems, and aims to provide a core material for an earth retaining wall that can be installed smoothly and with high precision inside soil cement that has high penetration resistance, an earth retaining wall equipped with this core material for an earth retaining wall, and a construction method for the same. [Means for solving the problem]

[0010] In order to achieve the above object, one aspect of the core material for an earth retaining wall according to the present invention is as follows: A core material for earth retaining walls that is applied when constructing a soil cement column-type continuous wall, which is an earth retaining wall, The core member has a suction tube extending in its longitudinal direction, When the core material is inserted into the soil cement, the soil cement located in front of the insertion direction is sucked through the suction pipe.

[0011] According to this aspect, the core material for an earth retaining wall used in constructing a soil cement diaphragm wall is provided with a suction pipe extending in its longitudinal direction, and when the core material is inserted into the soil cement, the soil cement located ahead in the insertion direction is sucked through the suction pipe, and the soil cement that acts as penetration resistance is recovered from ahead in the insertion direction of the core material, thereby significantly reducing the penetration resistance acting on the core material and enabling the core material to be erected smoothly and with high precision. For example, a vacuum device connected to the suction pipe is installed on the ground, and when the core material is inserted, the soil cement located ahead in the insertion direction of the core material is sucked in by a vacuum pump or the like that is driven.

[0012] Here, in order to enhance the effect of reducing the penetration resistance, multiple suction pipes may be attached to the core material, for example, suction pipes may be installed at multiple locations among the four boundary regions between the web and flange of the H-shaped steel that forms the core material. In addition, a vacuum pump that can gradually increase its suction performance may be applied, and if the penetration resistance changes depending on, for example, the insertion depth of the core material, the suction performance of the vacuum pump may be automatically adjusted in accordance with the change in penetration resistance.

[0013] Another aspect of the core material for an earth retaining wall according to the present invention is as follows: The end of the core material in the direction of insertion into the soil cement is tapered toward the tip, A cover plate is attached to the end.

[0014] According to this embodiment, the end of the core material in the direction of insertion into the soil cement is tapered toward the tip, and a cover plate is attached to this end, so that the cover plate, which follows the tapered shape, makes it easier for the soil cement to flow diagonally backward (opposite the insertion direction), thereby achieving even smoother installation of the core material.

[0015] In other words, in a configuration in which the web at the tip of the core material is tapered, as in the core material described in Patent Document 1, the tip of the flange that is not tapered can be the part that receives penetration resistance from the soil cement, but by attaching a tapered cover plate (for example, V-shaped or approximately V-shaped when viewed from the side) to the entire end of the core material as in this embodiment, the soil cement in front of the insertion direction can be made to flow diagonally backward along the cover plate, effectively reducing any penetration resistance that may act.

[0016] In another aspect of the core material for an earth retaining wall according to the present invention, The core member is formed by an H-shaped steel having a web and two flanges, The flange is characterized in that it is tapered toward the tip.

[0017] According to this aspect, the two flanges are tapered toward their tips, so that the cover plate can be stably supported by the tips of the two flanges and the tip of the web. For example, when a cover plate is attached to a web with a tapered tip as described in Patent Document 1, the cover plate is supported only by the single central web, which results in a lack of stability, and a separate reinforcing rib or the like is required to stably support the cover plate.

[0018] In another aspect of the core material for an earth retaining wall according to the present invention, The web is provided with a stud dowel as a shear resistance means, The stud dowel does not protrude laterally beyond the cover plate.

[0019] According to this aspect, in a configuration in which a stud dowel, which is a shear resistance means, is attached to the web, the stud dowel does not protrude laterally beyond the cover plate, thereby preventing the soil cement from exerting penetration resistance on the stud dowel.

[0020] When a soil cement diaphragm wall is connected to the side walls of the basement of a permanent building and used as part of the foundation of the permanent building, the vertical load caused by the building's own weight, etc. can be transmitted to the ground via the soil cement diaphragm wall. In this case, the vertical load transmitted to the core material is effectively transmitted to the surrounding soil cement via the stud dowels, forming a smooth load transmission mechanism in which the vertical load is transmitted to the ground via the soil cement.

[0021] In another aspect of the core material for an earth retaining wall according to the present invention, The web is characterized by having through holes that serve as shear resistance means.

[0022] According to this aspect, the web is provided with through-holes that act as shear resistance means, and as soil cement enters the through-holes, a load transfer mechanism is formed by the bearing pressure of the soil cement. In this form, reinforcing bars may be passed through the through-holes, in which case the reinforcing bars will further add resistance.

[0023] Moreover, one aspect of the earth retaining wall according to the present invention is as follows: The core material for the retaining wall is embedded inside the soil cement.

[0024] According to this embodiment, by incorporating the core material for the earth retaining wall of the present invention inside the soil cement, the core material is erected with high erection precision, resulting in a high-quality earth retaining wall that can demonstrate initial strength.

[0025] In addition, one aspect of the construction method of the earth retaining wall according to the present invention is to A method for constructing a soil cement diaphragm wall that is an earth retaining wall, comprising: The method includes a step of creating soil cement while drilling the ground, and inserting a core material into the soil cement before the soil cement hardens, The core member has a suction tube extending in its longitudinal direction, When inserting the core material into the soil cement, the soil cement located in front of the insertion direction is sucked through the suction pipe and temporarily discharged to the ground, After the installation of the core material is completed, the soil cement temporarily discharged to the ground is returned to the inside of the retaining wall through the suction pipe, while the suction pipe is pulled out.

[0026] According to this aspect, in the process of inserting the core material into the soil cement, the soil cement in front of the core material in the insertion direction is sucked through the suction pipe and temporarily discharged to the ground when the core material is inserted into the soil cement. This allows the soil cement that acts as penetration resistance to be recovered from the front of the core material in the insertion direction, significantly reducing the penetration resistance acting on the core material and enabling the core material to be installed smoothly and with high precision. Furthermore, after the installation of the core material is complete, the soil cement that was temporarily discharged to the ground is returned to the inside of the earth retaining wall through the suction pipe while the suction pipe is withdrawn, allowing the temporarily discharged soil cement to be used for the construction of the earth retaining wall without waste.

[0027] In another aspect of the construction method of the earth retaining wall according to the present invention, The core material is characterized in that the end portion in the direction of insertion into the soil cement is tapered toward the tip, and a cover plate is attached to the end portion.

[0028] According to this embodiment, the end of the core material in the direction of insertion into the soil cement is tapered toward the tip, and a cover plate is attached to this end, making it easier for the soil cement to flow diagonally backward with the cover plate following the tapered shape, thereby achieving even smoother installation of the core material. [Effects of the Invention]

[0029] As can be understood from the above explanation, the core material for an earth retaining wall, the earth retaining wall and its construction method of the present invention can provide a core material for an earth retaining wall that can be erected smoothly and with high precision inside soil cement with high penetration resistance, and an earth retaining wall equipped with this core material for an earth retaining wall and its construction method. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 2 is a perspective view showing an example of a core material for an earth retaining wall according to an embodiment. [Figure 2] FIG. 1 is a process diagram of an example of a construction method for an earth retaining wall according to an embodiment. [Figure 3] 2, this is a process diagram of an example of a construction method for an earth retaining wall according to the embodiment. [Figure 4] Continuing from FIG. 3, this is a process diagram of an example of a construction method for an earth retaining wall according to the embodiment. [Figure 5] 5 is a process diagram of an example of a construction method for an earth retaining wall according to an embodiment, following FIG. 4, and is also a vertical cross-sectional view showing an example of an earth retaining wall according to an embodiment. [Figure 6] FIG. 1 is a vertical cross-sectional view showing an example in which a retaining wall is used as part of the foundation of a building. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, the core material for an earth retaining wall, the earth retaining wall, and the construction method thereof according to the embodiment will be described with reference to the accompanying drawings. Note that in this specification and the drawings, substantially identical components are designated by the same reference numerals, and redundant explanations may be omitted.

[0032] [Core material for earth retaining wall according to the embodiment] First, an example of a core material for an earth retaining wall according to an embodiment will be described with reference to Fig. 1. Here, Fig. 1 is a perspective view showing an example of a core material for an earth retaining wall according to an embodiment.

[0033] The core material 40 for the retaining wall has a core material 10 (core material body) formed from H-shaped steel, a cover plate 20 attached to the end 15 of the core material 10 in the insertion direction, and a suction pipe 30 extending in the longitudinal direction of the core material 10.

[0034] The core 10 has a web 11 and two flanges 12, and an end 12a of each flange 12 is tapered (generally V-shaped when viewed from the front) toward the insertion direction.

[0035] The core material 10 in the illustrated example has multiple stud dowels 18 welded to the web 11 (in the illustrated example, there are two on one side of the web 11, for a total of four on both sides). Here, the stud dowels 18 do not protrude laterally beyond the cover plate 20. This prevents the soil cement from exerting penetration resistance on the stud dowels 18. As will be described later, the stud dowels 18 are an example of shear resistance means that transmits the vertical load, which is the weight of the building, from the core material 10 to the soil cement in an earth retaining wall connected to the building.

[0036] The cover plate 20 is a member made by bending a steel plate so that it follows the tapered line (approximately V-shaped line) of the ends 12a of the two flanges 12, and is welded to the ends 12a of the two flanges 12 and the end 11a of the web 11.

[0037] The suction pipe 30 is fixed to the boundary region between the web 11 of the core material 10 and one of the flanges 12, and in the illustrated example, two suction pipes 30 are fixed to the core material 10. Here, the number of suction pipes 30 may be one or three or more.

[0038] A plurality of curved engagement pieces 17 are attached to the core material 10 at intervals in the longitudinal direction.

[0039] On the other hand, a plurality of biasing members 36 made of springs or the like are attached to the suction tube 30 at intervals along its length, and a curved engagement hook 35 is attached to each biasing member 36. The biasing members 36 constantly bias the suction tube 30 in the Z direction, which is the direction in which the tips of the engagement hooks 35 abut against the suction tube 30.

[0040] When attaching the suction tube 30 to the core material 10, the suction tube 30 is inserted into each of the engageable pieces 17 of the core material 10, the engaging hooks 35 corresponding to the lower positions of each engageable piece 17 are aligned, and then the suction tube 30 is pulled slightly upward, so that the engaging hooks 35, which are biased in the Z direction by the biasing member 36, are lifted by the engageable piece 17 and then engage with the engageable piece 17.

[0041] Furthermore, when finally removing the suction tube 30 from the core material 10, the suction tube 30 is pushed slightly forward in the insertion direction, causing the engaging hook 35 to be lifted by the engaging piece 17 and disengaging the two, and then the suction tube 30 is pulled upward, causing the suction tube 30 to pass through each engaging piece 17 and be removed from the core material 10.

[0042] The cover plate 20 has a suction port 20a into which the end of the suction pipe 30 can be removably installed, and when inserting the core material 40 for the retaining wall into the soil cement, the end of the suction pipe 30 is installed in the suction port 20a.

[0043] The suction pipe 30 is connected to a vacuum pump 71 (see Figure 2) located on the ground, and when the core material 40 for the earth retaining wall is inserted into the soil cement in the X1 direction and erected, the vacuum pump 71 is driven to suck the soil cement in front of it in the X2 direction into the suction port 20a, and the soil cement that flows through the suction pipe 30 in the X3 direction is temporarily discharged to the ground. Here, "temporarily discharged" means that the soil cement is temporarily discharged and stored in a specified location, and then finally returned to the original soil cement.

[0044] According to the core material 40 for earth retaining walls, a suction pipe 30 is attached to the core material 10 and extends in the longitudinal direction thereof, so that when the core material 10 is inserted into the soil cement, the soil cement in front of the insertion direction is sucked through the suction pipe 30, and the soil cement that acts as penetration resistance is collected from in front of the insertion direction of the core material 10. This significantly reduces the penetration resistance acting on the core material 10, allowing the core material 10 to be erected smoothly and with high precision.

[0045] Furthermore, the end 15 of the core material 10 in the direction of insertion into the soil cement is tapered towards the tip, and a cover plate 20 is attached to this end 15, so that the planar cover plate 20 that follows the tapered shape makes it easier to flow the soil cement diagonally backward in the Y1 direction, thereby achieving even smoother insertion of the core material 10.

[0046] Furthermore, since the two flanges 12 of the core material 10 are tapered toward the tip, the cover plate 20 can be stably supported by the ends 12a of the two flanges 12 and the end 11a of the web 11.

[0047] Although not shown here, if the core material 10 can be smoothly installed simply by suctioning the soil cement in front of the insertion direction using the suction pipe 30, the tip of the flange of the core material 10 does not need to be tapered, and it is also not necessary to install a cover plate 20.

[0048] [Earth retaining wall construction method and earth retaining wall according to the embodiment] Next, a construction method of an earth retaining wall according to an embodiment and an example of an earth retaining wall will be described with reference to Figures 2 to 5. Here, Figures 2 to 5 are process diagrams of an example of a construction method of an earth retaining wall according to an embodiment, and Figure 5 is a vertical cross-sectional view showing an example of an earth retaining wall according to an embodiment.

[0049] As shown in FIG. 2, holes are drilled in the ground G for a soil cement diaphragm wall (an example of an earth retaining wall), and soil cement 50 is laid in the holes.

[0050] The soil cement 50 is produced by mixing and stirring earth and sand generated by excavating the ground G with cement milk discharged from the tip of a multi-shaft mixing auger or the like (not shown).

[0051] A vacuum pump 71 is installed on the ground, and the suction pipe 30 constituting the core material 40 for the retaining wall is connected to the vacuum pump 71 via a delivery pipe 74.

[0052] The vacuum pump 71 is connected to the temporary storage tank 72 via a separate delivery pipe 75, and the soil cement 51 is sucked into the vacuum pump 71 through the suction pipe 30 in the X3 direction and the delivery pipe 74 in the X4 direction, and is then circulated in the X5 direction via the delivery pipe 75 so that it can be temporarily discharged into the temporary storage tank 72.

[0053] The temporary reservoir tank 72 accommodates a discharge pump 73, to which a separate delivery pipe 76 is further attached.

[0054] Returning to FIG. 2, the core material 10 is inserted into the soil cement 50 laid on the ground G before the soil cement 50 hardens.

[0055] When inserting the core material 40 for the earth retaining wall into the soil cement 50, the vacuum pump 71 is driven to suck the soil cement 50 in the X2 direction ahead of the insertion direction of the core material 10, thereby forming a small void S in front of the core material 10 where no soil cement 50 is present. This void S suppresses the penetration resistance that the soil cement 50 may exert on the core material 10 being inserted in the X1 direction. Here, if the vacuum pump 71 is configured to be able to increase its suction performance in stages, when the penetration resistance changes depending on the insertion depth of the core material 10, the suction performance of the vacuum pump 71 can be automatically adjusted in accordance with the change in penetration resistance, making it possible to constantly form the void S in front of the core material 10 (this completes the process of inserting the core material 10 into the soil cement 50).

[0056] As shown in FIG. 3, the core material 40 for the earth retaining wall is inserted to a predetermined depth inside the soil cement 50, thereby completing the erection of the core material 10.

[0057] During the process of erecting the core material 10, a certain amount of soil cement 50 is temporarily discharged into the temporary storage tank 72 via the suction pipe 30, so that the top surface of the soil cement 50 is at a level below the ground surface.

[0058] Next, as shown in FIG. 4, a separate delivery pipe 77 is connected to the delivery pipe 76 connected to the discharge pump 73 , and the delivery pipe 77 is connected to the upper end of the suction pipe 30 .

[0059] Then, the suction pipe 30 installed on the core material 10 is removed from the core material 10 in the manner already described, and the suction pipe 30 is pulled upward in the X6 direction using a winch (not shown) on the ground or by hand.

[0060] When the suction pipe 30 is pulled out, the discharge pump 73 is driven, and the soil cement 51 temporarily discharged into the temporary storage tank 72 is sent out in the X7 direction through the delivery pipes 76, 77, and returned to the soil cement 50 in the X8 direction through the suction pipe 30.

[0061] In this way, by returning the temporarily discharged soil cement 51 into the soil cement 50 in parallel with the withdrawal of the suction pipe 30, a retaining wall 60 formed by the core material 10 and the soil cement 50 is constructed, as shown in Figure 5.

[0062] The soil cement continuous column wall 60 may be designed so that its tip reaches hard ground where sufficient tip bearing capacity can be obtained, or it may be designed so that its tip does not reach hard ground but can support vertical loads by the peripheral friction force between the peripheral surface of the soil cement continuous column wall 60 and the ground G.

[0063] According to this construction method, in the process of inserting the core material 10 into the soil cement 50, when the core material 10 is inserted into the soil cement 50, the soil cement 50 located in front of the insertion direction is sucked through the suction pipe 30 and temporarily discharged to the ground.By doing so, the soil cement 50 that acts as penetration resistance is recovered from in front of the insertion direction of the core material 10, thereby significantly reducing the penetration resistance acting on the core material 10 and enabling the core material 10 to be installed smoothly and with high precision.

[0064] Furthermore, after the installation of the core material 10 is completed, the soil cement 51 temporarily discharged on the ground is returned to the inside of the retaining wall through the suction pipe 30 while the suction pipe 30 is being pulled out, so that the temporarily discharged soil cement 51 can be used for the construction of the retaining wall 60 without waste.

[0065] Next, an application example of the earth retaining wall 60 will be described with reference to Fig. 6. Here, Fig. 6 is a vertical cross-sectional view showing an example in which the earth retaining wall is used as part of the foundation of a building.

[0066] The illustrated building 90 is constructed by connecting a side wall 82 of an underground section 81 of a building 80 located in ground G via a plurality of stud dowels 19 to a soil cement diaphragm column wall 60 constructed around the periphery of the building 80. For example, a soil cement diaphragm column wall 60 having a rectangular frame shape in plan view is constructed around the side wall 82 of the underground section 81 of a building 80 that is rectangular in plan view, and a plurality of stud dowels 19 are connected to each of a plurality of core materials 10 that make up the soil cement diaphragm column wall 60, connecting each stud dowel 19 to the underground section 81.

[0067] Here, the planar shape of the building 80 varies, and the soil cement diaphragm column wall 60 is constructed in a frame shape that corresponds to the planar shape of the building 80. Furthermore, depending on the state of the groundwater level and the presence or absence of ground improvement work around the earth retaining wall, a parent pile horizontal sheet pile wall having at least H-shaped steel as its constituent elements may be applied as the earth retaining wall. Furthermore, the base slab 83 may be supported by prefabricated piles such as steel pipe piles, PHC piles, PRC piles, and SC piles, or by cast-in-place piles.

[0068] Building 80 may be made of reinforced concrete, steel, or steel reinforced concrete, or a hybrid of these structures, and includes a variety of types of buildings, such as office buildings, apartment buildings, gymnasiums, shopping malls, and various public buildings.

[0069] The soil cement column-type continuous wall 60 shown in the figure not only serves as a retaining wall when constructing the building 80, but also functions as the foundation of the building 80 after it is constructed by being connected to the underground section 81 of the building 80.

[0070] A vertical load N due to the weight of the building 80 or the like is transmitted to the core material 10 via a plurality of stud dowels 19, and is then transmitted to the surrounding soil cement 50 via the stud dowels 18 provided in the core material 10.

[0071] The stud dowels 18 are shear resistance means, and a shear force Q acts on the stud dowels 18 to transmit a vertical load N to the soil cement 50. Here, the shear resistance means may be the stud dowels 18 in the illustrated example, or it may be through-holes (not shown) opened in the web of the core material 10 and soil cement entering these through-holes.

[0072] Due to the above-described flow of axial force transmission, the vertical load N due to the weight of the building 80 or the like is transmitted to the ground G via the soil cement diaphragm column wall 60. Note that compressive loads during earthquakes or strong winds are also transmitted in the same manner.

[0073] The present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0074] 10: Core material (core material body) 11:Web 11a: End 12: Flange 12a: End 15: End of insertion direction (end) 17: Engaged piece 18: Stud dowel (shear resistance means) 19: Stud dowel 20: Cover plate 20a: Suction port 30:Suction tube 35: Engagement hook 36: biasing member 40: Core material for earth retaining walls 50: Soil cement 60: Soil cement column-type continuous wall (earth retaining wall) 71: Vacuum pump 72: Temporary storage tank 73: Discharge pump 74:74,75,76,77: Delivery pipe 80: Building 81: Underground 82: Side wall 83: Bottom board 90: Building G: Ground S: void N: Vertical load Q: Shear force

Claims

1. A core material for earth retaining walls that is applied when constructing a soil cement column-type continuous wall, which is an earth retaining wall, The core member has a suction tube extending in its longitudinal direction, A core material for an earth retaining wall, characterized in that when the core material is inserted into the soil cement, the soil cement located in front of the insertion direction is sucked through the suction pipe.

2. The core material comprises at least a web, The end of the core material in the direction of insertion into the soil cement is tapered toward the tip, 2. The core material for an earth retaining wall according to claim 1, wherein a cover plate is attached to the end portion.

3. The core member is formed by an H-shaped steel having a web and two flanges, 3. The core material for an earth retaining wall according to claim 2, wherein the flange is tapered toward its tip.

4. The web is provided with a stud dowel as a shear resistance means, A core material for an earth retaining wall according to claim 2 or claim 3 depending on claim 2, characterized in that the stud dowel does not protrude laterally beyond the cover plate.

5. A core material for an earth retaining wall according to claim 2 or claim 3 depending on claim 2, characterized in that the web is provided with through holes as shear resistance means.

6. An earth retaining wall, characterized in that the core material for an earth retaining wall according to any one of claims 1 to 5 is embedded inside the soil cement.

7. A method for constructing a soil cement diaphragm wall that is an earth retaining wall, comprising: The method includes a step of creating soil cement while drilling the ground, and inserting a core material into the soil cement before the soil cement hardens, The core member has a suction tube extending in its longitudinal direction, When inserting the core material into the soil cement, the soil cement located in front of the insertion direction is sucked through the suction pipe and temporarily discharged to the ground, A method for constructing an earth retaining wall, characterized in that after the installation of the core material is completed, the soil cement temporarily discharged to the ground is returned to the inside of the earth retaining wall through the suction pipe, while the suction pipe is pulled out.

8. The construction method for a retaining wall according to claim 7, characterized in that the end of the core material in the direction of insertion into the soil cement is tapered toward the tip, and a cover plate is attached to the end.

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