Shaft wall construction method

Abstract

To provide a member to be cut with improved workability, a shaft wall and a construction method of the shaft wall.SOLUTION: A member to be cut 20 forms a drilling possible area at a part of a shaft wall 100 made of reinforced concrete. The member to be cut 20 comprises a resin-made outer wall 22, a resin-made inner wall 23 and a resin-made connection material 24. The outer wall 22 constitutes a part of an outer surface 100a of the shaft wall 100. The inner wall 23 constitutes a part of an inner surface 100b of the shaft wall 100. The connection material 24 is placed between the outer wall 22 and the inner wall 23 and connects the outer wall 22 and the inner wall 23. Concrete of the shaft wall 100 can be filled between the outer wall 22 and the inner wall 23 and a reinforcement bar 13 of a shaft wall body 10 can be provided between a peripheral margin 22b of the outer wall 22 and a peripheral margin 23b of the inner wall 23.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a workpiece, a shaft wall, and a method for constructing a shaft wall. [Background technology]

[0002] Conventionally, the shield tunneling method, which uses a shield tunneling machine, has been used to form tunnels and the like. In this shield tunneling method, a starting shaft is first formed at the starting point, and then the tunnel is dug vertically from the ground to the depth at which the tunnel will be formed. The shield tunneling machine is then lowered into the shaft and used to excavate the tunnel horizontally. In addition, arrival shafts similar to the starting shaft are provided at the end point of the tunnel or at predetermined intermediate points, and the shield tunneling machine is driven to reach these shafts.

[0003] Shafts such as departure shafts have shaft walls (underground walls) formed to prevent groundwater from spouting out, ground collapse, etc. These shaft walls may be made of reinforced concrete, in which concrete is reinforced with rebar. Since the excavable area, which is the area through which the shield tunneling machine passes, cannot be reinforced with rebar or the like, the excavable area is reinforced with a high-strength fiber-reinforced resin or the like that is capable of excavation (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-154475 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the shaft wall in Patent Document 1 is formed entirely from reinforced concrete. For this reason, fiber-reinforced resin or the like is embedded inside the concrete even in the excavable area. Here, when the entire shaft wall is made of concrete, the thickness of the excavable area is generally formed thin to facilitate excavation work in the excavable area. In this case, when forming the shaft wall, it is necessary to prepare two types of formwork: a main body formwork for forming the other area not including the excavable area (i.e., the shaft wall main body), and an excavation area formwork for forming the excavable area. This makes the work of forming the shaft wall complicated, which is a factor that hinders improvement in workability.

[0006] Furthermore, when reinforcing the excavable area of ​​the shaft wall with fiber-reinforced resin or the like, it is conceivable that, for example, during excavation of the excavable area, the cuttable member that forms the excavable area may shift at the boundary between the area where the reinforcing steel is embedded (i.e., the shaft wall body). For this reason, it is necessary to prevent the cuttable member from shifting, for example, by devising the shape of the fiber-reinforced resin or the like, but this makes the shape of the cuttable member complex, which becomes a factor that hinders improvement of workability.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a cut member, a shaft wall, and a shaft wall construction method that can improve workability. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention proposes the following means. "1" The cuttable member of the present invention is a cuttable member for forming an excavable area in a part of a shaft wall made of reinforced concrete, and comprises a resin outer wall that forms part of the outer surface of the shaft wall, a resin inner wall that forms part of the inner surface of the shaft wall, and a resin connecting material that is arranged between the outer wall and the inner wall and connects the outer wall and the inner wall, and the concrete of the shaft wall can be filled between the outer wall and the inner wall, and the steel bars of the shaft wall can be arranged between the peripheral edge of the outer wall and the peripheral edge of the inner wall.

[0009] In the case of the above-mentioned cuttable member, a resin connecting material is placed between the resin outer wall and the resin inner wall, and the outer wall and inner wall are connected by the connecting material. Furthermore, concrete is filled between the outer wall and the inner wall to form an excavable area in part of the shaft wall. Therefore, the outer wall and inner wall forming the excavable area can also serve as formwork. This makes it possible to eliminate the need for formwork for the excavation area, which was previously required to form the excavable area. Therefore, the work of forming the shaft wall can be simplified, and workability can be improved.

[0010] Furthermore, the rebar for the shaft wall was placed between the peripheral edge of the outer wall and the peripheral edge of the inner wall. Specifically, in the shaft wall, the rebar was extended from the shaft wall main body in which the rebar was embedded to the cut member having an excavable area. Therefore, the boundary between the shaft wall main body and the cut member can be reinforced with the rebar extended from the shaft wall main body to the cut member. In other words, with a simple configuration in which the rebar for the shaft wall is placed between the peripheral edge of the outer wall and the peripheral edge of the inner wall, strength can be ensured at the boundary between the shaft wall main body and the cut member. This simplifies the work of forming the shaft wall and improves workability. In addition, by ensuring strength at the boundary between the shaft wall main body and the cut member, it is possible to prevent the cut member from shifting from the shaft wall main body at the boundary between the shaft wall main body and the cut member, for example, during excavation of the excavable area.

[0011] [2] In this embodiment, an opening may be formed around the entire periphery between the peripheral edge of the outer wall and the peripheral edge of the inner wall.

[0012] In this case, the area between the periphery of the outer wall and the periphery of the inner wall is open all around. Therefore, the reinforcing bars of the shaft wall can be easily placed all around between the periphery of the outer wall and the periphery of the inner wall. This ensures strength all around the boundary between the cutting member and the shaft wall body.

[0013] "3" In this embodiment, at least one of the outer wall and the inner wall may be made of fiber-reinforced plastic, and the orientation direction of at least a portion of the fibers composited into the fiber-reinforced plastic may be the circumferential direction of the shaft wall.

[0014] Here, external bending stresses due to earth pressure and water pressure act in a direction that changes the circumferential shape of the excavable area. Therefore, at least one of the outer and inner walls is made of fiber-reinforced plastic, with the fiber orientation oriented in the circumferential direction of the shaft wall. This simple structure, with the fiber orientation oriented in the circumferential direction of the shaft wall, ensures the strength of the excavable area, where external bending stresses act.

[0015] [4] In this embodiment, the connecting material may be attached without penetrating the inner wall and the outer wall.

[0016] When connecting materials are attached by penetrating the inner and outer walls, it is necessary to remove the portions of the connecting materials that penetrate the inner and outer walls and protrude outside the cut-off members. Alternatively, it is necessary to remove the connecting materials that protrude from the inner and outer walls from the cut-off members and fill the resulting openings with concrete. This hinders the improvement of workability. Furthermore, if the connecting materials penetrate the inner and outer walls, the strength of the inner and outer walls may be reduced. Therefore, the connecting material was attached so that it did not penetrate the inner and outer walls. This eliminates the need to remove the protruding portion of the cut-out member or to extract the connecting material from the cut-out member and fill the opening with concrete, improving workability. Furthermore, it also prevents a decrease in the strength of the inner and outer walls.

[0017] [5] In this embodiment, the connecting material may be disposed near the excavation periphery of the excavable area.

[0018] Here, large shear forces due to external earth pressure and water pressure act on the areas of the excavable area near the excavation periphery. Therefore, the connecting materials are placed near the excavation periphery in the excavable area. This simple structure of placing the connecting materials near the excavation periphery ensures the strength of the areas near the excavation periphery where large shear forces act from the outside.

[0019] "6" In this embodiment, the concrete filled between the outer wall and the inner wall may be thinner than the concrete filled in the shaft wall body excluding the cut member of the shaft wall.

[0020] In this case, the concrete filled between the outer and inner walls is thinner than the concrete filled in the shaft wall body, which makes it easier to excavate the excavable area. Furthermore, the outer and inner walls also serve as formwork when filling the concrete. This means that the concrete between the outer and inner walls can be thinner than the concrete in the shaft wall itself, without the need for formwork for the excavation area that would be required if the entire shaft wall were made of reinforced concrete. This simplifies the work of forming the shaft wall and improves construction efficiency.

[0021] [7] The shaft wall according to the present invention has an excavable area formed by the cuttable member described in any one of [1] to [6].

[0022] In the case of the shaft wall described above, a resin connecting material was placed between a resin outer wall and a resin inner wall, and concrete was filled between the outer and inner walls to form a cuttable member. By forming an excavable area with this cuttable member, an excavable area was formed in part of the shaft wall. Therefore, the outer and inner walls that form the excavable area can also serve as formwork. This makes it possible to eliminate the need for formwork for the excavation area that was previously required to form the excavable area. This simplifies the work of forming the shaft walls and improves workability.

[0023] Furthermore, the rebar of the shaft wall was placed between the peripheral edge of the outer wall and the peripheral edge of the inner wall. Specifically, in the shaft wall, the rebar was extended from the shaft wall main body in which the rebar was embedded to the cut member having an excavable area. Therefore, the boundary between the shaft wall main body and the cut member can be reinforced with the rebar extended from the shaft wall main body to the cut member. In other words, strength can be ensured at the boundary between the shaft wall main body and the cut member with a simple configuration that simply places the rebar of the shaft wall between the peripheral edge of the outer wall and the peripheral edge of the inner wall. The work of forming the shaft wall can be simplified, improving workability. By ensuring strength at the boundary between the shaft wall main body and the cut member, it is possible to prevent the cut member from shifting from the shaft wall main body at the boundary between the shaft wall main body and the cut member, for example, during excavation of an excavable area.

[0024] "8" The method for constructing a shaft wall according to the present invention includes a first step of installing the reinforcing bars and formwork of the shaft wall together with the cuttable member described in any one of "1" to "6", a second step of pouring concrete inside the formwork and between the outer wall and the inner wall, and a third step of removing the formwork, wherein in the first step, the formwork is not installed in the part of the cuttable member.

[0025] In the above-described shaft wall construction method, reinforcing bars and formwork are installed along with the outer wall, inner wall, and connecting material that constitute the cuttable member. Here, the outer wall and inner wall that constitute the cuttable member can also serve as formwork for the cuttable member. Therefore, in the first step of installing the formwork, the formwork is not set on the part of the cuttable member. This eliminates the need to set the formwork on the part of the cuttable member in the formwork setting step, and further eliminates the need to remove the formwork from the cuttable member in the formwork removal step. This improves workability in the shaft wall construction method. [Effects of the Invention]

[0026] According to the present invention, the concrete of the shaft wall is filled between the outer wall and the inner wall, and the steel bars of the shaft wall are placed between the peripheral edges of the outer wall and the inner wall, thereby improving workability. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a perspective view showing a shaft wall according to a first embodiment of the present invention. [Figure 2] This is a modified example showing a case where the shaft wall is a rectangular shaft. [Figure 3] FIG. 2 is a front view of the workpiece shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view taken along line VV in FIG. [Figure 6] 1 is a cross-sectional view showing the state in which the workpiece, reinforcing bar, and frame wall according to the first embodiment of the present invention have been installed. FIG. [Figure 7] FIG. 10 is a front view of a workpiece according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, a workpiece, a shaft wall, and a shaft wall construction method according to a first embodiment of the present invention will be described with reference to the drawings. [First embodiment] As shown in Figures 1, 2, and 3, the shaft wall 100 comprises a shaft wall main body 10 and a member to be cut 20. The shaft wall main body 10 is a wall made of reinforced concrete in which reinforcing bars 13 (see Figures 4 and 5) are embedded inside concrete 12. The member to be cut 20 is a member in which a resin outer wall 22 and a resin inner wall 23 are connected by a resin connecting material 24. In the member to be cut 20, concrete 26 (both, see Figure 4) is filled (cast) in a space 25 between the outer wall 22 and the inner wall 23. The member to be cut 20 comprises an excavable area 28 that can be excavated (cut) by, for example, a shield tunneling machine (not shown). The excavable area 28 is the area inside a circle indicated by an imaginary line. That is, the shaft wall 100 is provided with a cuttable member 20 in a portion made of reinforced concrete, and an excavable area 28 is formed in the cuttable member 20. In the excavable area 28, not only the cuttable member 20 but also the concrete filled in the cuttable member 20 can be excavated. Depending on the size of the excavable area 28, multiple cuttable members 20 may be arranged in the height direction or circumferential direction, which will be described later. The cuttable member 20 will be described in detail later.

[0029] The shaft wall 100 is provided to reinforce the inner wall of a vertical hole extending from above ground to underground. The shaft wall 100 is used, for example, as the start or end point of shield excavation during tunnel construction for a subway or the like. The outer shape of the shaft wall 100 may be cylindrical as shown in FIG. 1 or a square prism (rectangular) as shown in FIG. 2. Furthermore, the outer shape of the shaft wall 100 may be a shape other than cylindrical or square prism, and there are no particular limitations on the outer shape. Hereinafter, the circumferential direction relative to the axis of the shaft wall 100 may be referred to as the "circumferential direction," and the axial direction may be referred to as the "height direction."

[0030] When excavating an underground layer laterally using a shield machine, the shield machine is first brought into the shaft wall 100. Next, the shield machine starts by excavating the inner wall of the shaft wall 100 laterally. Alternatively, the shaft wall 100 may be set at the end point of excavation by the shield machine, and used as the exit of the shield machine that has excavated the underground layer. In this way, underground tunnel construction is carried out with the shaft wall 100 as the start or end point. Examples of shield machines include mud pressure shields and slurry shields.

[0031] The concrete of the shaft wall 100 is used to reinforce the excavated wall surface when forming the shaft wall 100. Here, the side of the excavation created by excavating a vertical hole vertically in the ground may collapse due to earth pressure or water pressure, or groundwater may leak out. To prevent this, the shaft wall 100 is formed on the side of the excavation. The construction method for forming the shaft wall 100 will be explained in detail later.

[0032] As shown in Figures 3 to 5, the cut member 20 comprises an outer wall 22, an inner wall 23, and a plurality of connecting members 24. The outer wall 22 is formed in a curved or flat shape along the outer surface 10a of the shaft wall main body 10. The outer wall 22 is formed, for example, in a rectangular shape when viewed from the front, and further has a rectangular cross section in the circumferential direction. The outer wall 22 is arranged flush with the outer surface 10a of the shaft wall main body 10. In other words, the outer wall 22 constitutes part of the outer surface 100a of the shaft wall 100. The outer wall 22 is a resin member formed of, for example, fiber-reinforced plastic. In the outer wall 22, the orientation direction of at least a part of the fibers compounded in the fiber-reinforced plastic is oriented in the circumferential direction of the shaft wall 100.

[0033] The inner wall 23 is formed in a curved or flat shape along the inner surface 10b of the shaft wall main body 10. The inner wall 23 is arranged so that the wall surfaces face the outer wall 22. Like the outer wall 22, the inner wall 23 is formed in a rectangular shape when viewed from the front, and has a rectangular cross section in the circumferential direction. The inner wall 23 is arranged flush with the inner surface 10b of the shaft wall main body 10. In other words, the inner wall 23 constitutes part of the inner surface 100b of the shaft wall 100. The inner wall 23 is, for example, a resin member formed of fiber reinforced plastic, similar to the outer wall 22. In the inner wall 23, similar to the outer wall, the orientation direction of at least a part of the fibers compounded in the fiber reinforced plastic is oriented in the circumferential direction of the shaft wall 100.

[0034] Examples of fiber-reinforced plastics that form the outer wall 22 and the inner wall 23 include those made by compounding fibers such as glass fiber and carbon fiber with resins such as urethane resin, epoxy resin, polyester resin, and vinyl ester resin. The physical properties of fiber-reinforced plastics are set such that their elastic modulus is equal to or greater than that of concrete. The surface shape of the outer wall 22 and the inner wall 23 is formed, for example, with sand, calcium carbonate paper, etc. Furthermore, the dimensions of the outer wall 22 and the inner wall 23 are set, for example, to a thickness T of 5 to 50 mm, a width W in the height direction of 100 to 1500 mm, and a length L in the circumferential direction of 3000 to 16000 mm. 3 to 5, in the shaft wall 100 according to this embodiment, the cut members 20 are not arranged in multiple rows in the height direction or circumferential direction, but there is only one cut member 20. Although not shown here, for example, when multiple cut members 20 are arranged (stacked) in the height direction, the overall width in the height direction of the multiple cut members 20 can be set to, for example, about 3000 to 16000 mm.

[0035] In the first embodiment, an example is described in which the circumferential cross sections of the outer wall 22 and the inner wall 23 are formed in a rectangular shape. However, as other examples, the circumferential cross sections may be formed in a corrugated shape, a groove shape, or an uneven shape. Furthermore, in the first embodiment, an example in which both the outer wall 22 and the inner wall 23 are made of fiber-reinforced plastic will be described, but one of the outer wall 22 and the inner wall 23 may be made of fiber-reinforced plastic.

[0036] The connecting member 24 is disposed between the outer wall 22 and the inner wall 23 so as to intersect (orthogonal to) the outer wall 22 and the inner wall 23. The connecting member 24 is a resin member that connects the outer wall 22 and the inner wall 23. Specifically, the connecting member 24 is connected, for example, with an adhesive or an angle (not shown) in a state in which the outer end 24a is in contact with the inner surface 22a of the outer wall 22. When the outer end 24a of the connecting member 24 is connected to the inner surface 22a of the outer wall 22 with an angle, for example, the angle is attached to the outer end 24a of the connecting member 24 and the inner surface 22a of the outer wall 22 with a bolt or the like.

[0037] Furthermore, the connecting member 24 is connected, for example, with an adhesive or an angle (not shown) in a state where the inner end 24b is in contact with the inner surface 23a of the inner wall 23. When the inner end 24b of the connecting member 24 is connected to the inner surface 23a of the inner wall 23 with an angle, for example, the angle is attached to the inner end 24b of the connecting member 24 and the inner surface 23a of the inner wall 23 with a bolt or the like.

[0038] That is, the multiple connection members 24 are attached without penetrating the inner wall 23 and the outer wall 22. In this state, the multiple connection members 24 are attached with their wider surfaces facing the circumferential direction. When attached between the inner wall 23 and the outer wall 22, the multiple connecting members 24 are arranged at regular intervals (equal intervals) in the circumferential direction and at regular intervals (equal intervals) in the height direction. As a result, the outer wall 22 and the inner wall 23 are assembled at intervals by the multiple connecting members 24. A space 25 that can be filled with concrete 26 is formed between the outer wall 22 and the inner wall 23. In this state, the space between the peripheral edge 22b of the outer wall 22 and the peripheral edge 23b of the inner wall 23 is open all around so that the concrete 12 and reinforcing bars 13 of the shaft wall main body 10 can be placed. In other words, the space between the peripheral edge 22b of the outer wall 22 and the peripheral edge 23b of the inner wall 23 is not closed all around.

[0039] The space 25 between the outer wall 22 and the inner wall 23 is filled (cast) with concrete 26, which forms part of the shaft wall 100, similar to the shaft wall main body 10. The concrete 26 is filled into the space 25 between the outer wall 22 and the inner wall 23, thereby forming the cuttable member 20. The cuttable member 20 has an excavable area 28 that is excavated (cut) by, for example, a shield tunneling machine (not shown). In other words, the excavable area 28 is formed in the cuttable member 20. The excavable area 28 has a circular outer periphery that corresponds to, for example, the excavation section of the shield tunneling machine. Note that in the actual shaft wall 100, the boundary line of the excavable area 28 is not shown. The boundary line shown is an imaginary line.

[0040] Here, an opening is formed around the entire periphery between the peripheral edge 22b of the outer wall 22 and the peripheral edge 23b of the inner wall 23. Therefore, the concrete 26 (hereinafter simply referred to as the concrete 26) filled in the space 25 between the outer wall 22 and the inner wall 23 is integrally connected to the concrete 12 of the shaft wall main body 10 around the entire periphery. In other words, a portion of the concrete 12 cast in the shaft wall main body 10 is filled as the concrete 26 around the entire periphery in the space 25 between the outer wall 22 and the inner wall 23.

[0041] Moreover, the concrete 26 is formed so that the concrete thickness Tc1 is thinner than the concrete thickness Tc2 of the concrete 12 filled in the shaft wall main body 10. Furthermore, the reinforcing bars 13 of the shaft wall main body 10 are arranged around the entire circumference in the concrete 26 filled between the peripheral edge 22b of the outer wall 22 and the peripheral edge 23b of the inner wall 23. Specifically, the reinforcing bars 13 (ends of the reinforcing bars 13) of the shaft wall main body 10 are embedded (arranged) in areas avoiding the excavable area 28 around the entire circumference of the concrete 26 filled between the peripheral edge 22b of the outer wall 22 and the peripheral edge 23b of the inner wall 23. Note that the ends of the reinforcing bars 13 may overlap the connecting members 24 in the height direction or circumferential direction, for example, as long as they are in areas avoiding the excavable area 28.

[0042] Next, a construction method for the shaft wall 100 of the first embodiment will be described with reference to Figures 5 and 6. The construction method for the shaft wall 100 includes the following first, second and third steps. As shown in Figure 6, in the first step, the outer wall 22 and inner wall 23 of the member to be cut 20 are assembled using a plurality of connecting members 24. The member to be cut 20 has an opening around the entire periphery between the peripheral portion 22b of the outer wall 22 and the peripheral portion 23b of the inner wall 23. Next, with the member to be cut 20 installed in the area where the shaft wall 100 is to be formed, the reinforcing bars 13 and formwork 14 of the shaft wall 100 (i.e., the shaft wall main body 10) are installed.

[0043] When the reinforcing bars 13 and formwork 14 of the shaft wall main body 10 are installed, the reinforcing bars 13 of the shaft wall main body 10 are positioned in the opening that covers the entire circumference between the peripheral portion 22b of the outer wall 22 and the peripheral portion 23b of the inner wall 23 of the cut member 20, avoiding the excavable area 28 (see Figure 3). In addition, the outer wall 22 and inner wall 23 of the member to be cut 20 also serve as formwork for the concrete 26 to be filled inside the member to be cut 20. Therefore, when installing the reinforcing bars 13 and formwork 14 of the shaft wall main body 10, it is possible to avoid installing the formwork 14 in the part of the member to be cut 20.

[0044] Next, in the second step, concrete is poured into the internal space (inside the formwork 14) 16 formed by the formwork 14 of the shaft wall main body 10, and into the space 25 between the outer wall 22 and inner wall 23 of the cut member 20. As a result, the concrete 12 of the shaft wall main body 10 and the concrete 26 of the cut member 20 (both see Figure 5) are poured together.

[0045] 5 and 6, in the third step, the formwork 14 of the shaft wall main body 10 is removed. In this state, the reinforcing bars 13 of the shaft wall main body 10 are arranged in the concrete 26 filled in the opening around the entire periphery between the peripheral portion 22b of the outer wall 22 and the peripheral portion 23b of the inner wall 23 of the cut member 20, avoiding the excavable area 28 (see FIG. 3).

[0046] As described above, according to the workpiece 20 and shaft wall 100 of the first embodiment, the following actions and effects can be obtained as shown in FIGS. That is, the outer wall 22 and the inner wall 23 are connected by a plurality of connecting members 24. Furthermore, concrete 12 is filled into the space 25 between the outer wall 22 and the inner wall 23 to form a cuttable member 20 in a part of the shaft wall 100. An excavable area 28 is formed in the cuttable member 20. Therefore, the outer wall 22 and the inner wall 23 that form the excavable area 28 (i.e., the cuttable member 20) can also serve as formwork. This makes it possible to eliminate the need for formwork (hereinafter sometimes referred to as formwork for the excavation area) that is required to form the cuttable member 20. Therefore, the work of forming the shaft wall 100 can be simplified, and workability can be improved.

[0047] Furthermore, the reinforcing bars 13 of the shaft wall main body 10 were placed between the peripheral portion 22b of the outer wall 22 and the peripheral portion 23b of the inner wall 23. Specifically, in the shaft wall 100, the reinforcing bars 13 were extended from the shaft wall main body 10 in which the reinforcing bars 13 were embedded to the cut member 20 which has the excavable area 28. Therefore, the boundary 31 between the shaft wall main body 10 and the cut member 20 can be reinforced by the reinforcing bars 13 extended from the shaft wall main body 10 to the cut member 20. That is, strength can be ensured at the boundary 31 between the shaft wall main body 10 and the member to be cut 20 with a simple configuration that simply involves placing the reinforcing bars 13 of the shaft wall main body 10 between the peripheral portion 22b of the outer wall 22 and the peripheral portion 23b of the inner wall 23. This simplifies the work of forming the shaft wall 100 and improves workability. In addition, by ensuring strength at the boundary 31 between the shaft wall main body 10 and the cuttable member 20, it is possible to prevent the cuttable member 20 from shifting from the shaft wall main body 10 at the boundary 31 between the shaft wall main body 10 and the cuttable member 20, for example, during excavation of the excavable area 28.

[0048] In addition, an opening is made around the entire circumference between the peripheral edge 22b of the outer wall 22 and the peripheral edge 23b of the inner wall 23. Therefore, the reinforcing bars 13 of the shaft wall main body 10 can be easily arranged around the entire circumference between the peripheral edge 22b of the outer wall 22 and the peripheral edge 23b of the inner wall 23. This ensures strength around the entire circumference of the boundary 31 between the member to be cut 20 and the shaft wall main body 10.

[0049] Here, for example, external bending stress due to earth pressure or water pressure acts in a direction that changes the circumferential shape of the excavable area 28. Therefore, the outer wall 22 and the inner wall 23 are formed from fiber-reinforced plastic, with the fiber orientation direction being the circumferential direction of the shaft wall 100. This makes it possible to ensure the strength of the excavable area 28, which is subjected to external bending stress, with a simple configuration in which the fiber orientation direction is the circumferential direction of the shaft wall 100. In addition, the connecting members 24 are attached with their wide surfaces facing the circumferential direction, which further ensures the strength of the excavable area 28, which is subjected to external bending stress in a direction that changes the circumferential shape.

[0050] Furthermore, for example, when a plurality of connecting members 24 are attached by penetrating the inner wall 23 and the outer wall 22, it is necessary to remove the portions of the connecting members 24 that have penetrated the inner wall 23 and the outer wall 22 and protruded outside the cut member 20. Alternatively, it is necessary to remove the connecting members 24 that protrude from the inner wall 23 and the outer wall 22 from the cut member 20, and fill the resulting openings with concrete. This hinders improvement of workability. Furthermore, if the connecting members 24 penetrate the inner wall 23 or the outer wall 22, there is a risk that the strength of the inner wall 23 or the outer wall 22 will be reduced. Therefore, multiple connecting members 24 are attached so as not to penetrate the inner wall 23 and the outer wall 22. This eliminates the need for a process of removing the protruding portions of the cut member 20 or a process of extracting the connecting members 24 from the cut member 20 and filling the openings with concrete, improving workability. Furthermore, it is possible to prevent a decrease in the strength of the inner wall 23 and the outer wall 22.

[0051] Furthermore, the concrete 26 filled between the outer wall 22 and the inner wall 23 is thinner than the concrete 12 filled in the shaft wall body 10. This makes it easier to perform excavation work when excavating the excavable area 28. In addition, the outer wall 22 and the inner wall 23 also serve as formwork when filling with concrete 26. Therefore, it is not necessary to use formwork for the excavation area, which would have been necessary if the entire shaft wall 100 were made of reinforced concrete, and the concrete 26 between the outer wall 22 and the inner wall 23 can be made thinner than the concrete 12 of the shaft wall main body 10. This simplifies the work of forming the shaft wall 100 and improves workability.

[0052] Furthermore, according to the construction method for the shaft wall 100 of the first embodiment, as shown in FIGS. 5 and 6, the reinforcing bars 13 and formwork 14 are installed together with the outer wall 22, inner wall 23, and multiple connecting members 24 that constitute the member to be cut 20. Here, the outer wall 22 and inner wall 23 that constitute the member to be cut 20 can also serve as the formwork for the member to be cut 20. Therefore, in the first step of installing the reinforcing bars 13 and formwork 14, it is possible to avoid installing the reinforcing bars 13 and formwork 14 in the portion of the member to be cut 20. This makes it possible to omit the work of installing the reinforcing bars 13 and formwork 14 in the portion of the member to be cut 20 in the first step of installing the reinforcing bars 13 and formwork 14, and further, it is possible to omit the work of removing the formwork 14 from the member to be cut 20 in the third step of removing the reinforcing bars 13 and formwork 14. This improves workability in the construction method for the shaft wall 100.

[0053] Next, a cut member according to a second embodiment will be described with reference to Fig. 7. In the second embodiment, the same or similar members as those of the cut member 20 according to the first embodiment will be given the same reference numerals and detailed description thereof will be omitted. [Second embodiment] 7, the cuttable member 50 differs from the cuttable member 20 of the first embodiment in that a plurality of connecting members 52 are arranged on the outer wall 22 and the inner wall 23 near the excavation periphery 55 of the excavable area 54, but the other configurations are the same as those of the first embodiment. The excavation periphery 55 is a portion corresponding to the outer periphery of the excavable area 54. The excavable area 54 has an excavation periphery 55 formed in a circle, and a plurality of connecting members 52 are connected to the excavation periphery 55. The connecting members 52 are formed in the same manner as the connecting members 24 of the first embodiment.

[0054] Here, for example, a large shear force due to external earth pressure or water pressure acts on an area in the excavable area 54 near the excavation periphery 55. Therefore, in the second embodiment, a plurality of connecting members 52 are arranged in the excavable area 54 near the excavation periphery 55. In other words, the plurality of connecting members 52 are arranged so that they are denser at the excavation periphery 55 than at the center. This makes it possible to ensure the strength of the area near the excavation periphery 55, where a large shear force acts from the outside, with a simple configuration in which the connecting members 52 are arranged near the excavation periphery 55.

[0055] As explained above, according to the second embodiment of the cuttable member 50, the shaft wall 100 equipped with the cuttable member 50, and the construction method for the shaft wall 100, the outer wall 22 and the inner wall 23 are connected by a plurality of connecting members 52. Furthermore, the plurality of connecting members 52 are arranged near the excavation periphery 55 of the excavable area 54. In addition, by filling the space 25 between the outer wall 22 and the inner wall 23 with concrete 26 (see FIG. 5), the cuttable member 50 is formed in a part of the shaft wall 100, and the excavable area 54 is formed in the cuttable member 50. Therefore, the outer wall 22 and the inner wall 23 that form the excavable area 54 (i.e., the cut member 50) can also serve as formwork. This makes it possible to eliminate the need for a formwork for the excavation area that is required to form the cut member 50. Therefore, the work of forming the shaft wall 100 of the second embodiment can be simplified, and workability can be improved.

[0056] Furthermore, with the simple configuration of arranging multiple connecting members 52 near the excavation periphery 55 of the excavable area 54, the strength of the area near the excavation periphery 55 where a large shear force acts from the outside can be ensured.

[0057] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0058] For example, the inner wall 23, the outer wall 22, and the connecting members 24 and 52 do not have to be made of fiber-reinforced plastic. The connectors 24 and 52 may pass through the inner wall 23 and the outer wall 22 .

[0059] In addition, within the scope of the spirit of the present invention, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described modifications may be combined as appropriate. [Explanation of symbols]

[0060] 10...shaft wall body, 12, 26...concrete, 13...reinforcing bars, 14...formwork, 16...internal space of formwork (inside of formwork), 20, 50...part to be cut, 22...outer wall, 22b...periphery of outer wall, 23...inner wall, 23b...periphery of inner wall, 24, 52...connecting material, 28, 54...excavable area, 55...periphery of excavation, 100...shaft wall, 100a...outer surface of shaft wall, 100b...inner surface of shaft wall.

Claims

1. A method for constructing a shaft wall, comprising a first step of installing a reinforcing bar and formwork for the shaft wall together with a cut member for forming an excavable area in a part of the shaft wall made of reinforced concrete, The workpiece is A resin outer wall that constitutes a part of the outer surface of the shaft wall; A resin inner wall that constitutes a part of the inner surface of the shaft wall; a resin connecting member disposed between the outer wall and the inner wall and connecting the outer wall and the inner wall, The concrete of the shaft wall can be filled between the outer wall and the inner wall, Reinforcing bars of the shaft wall can be arranged between the peripheral edge of the outer wall and the peripheral edge of the inner wall, The construction method of the shaft wall comprises: A second step of pouring concrete into the formwork and between the outer wall and the inner wall; and a third step of removing the formwork, A shaft wall construction method characterized in that in the first step, the formwork is not installed on the cut member.

2. 2. The method for constructing a shaft wall according to claim 1, wherein an opening is provided around the entire periphery between the peripheral edge of the outer wall and the peripheral edge of the inner wall.

3. At least one of the outer wall and the inner wall is made of fiber-reinforced plastic, 3. A method for constructing a shaft wall according to claim 1 or claim 2, characterized in that the orientation direction of at least a portion of the fibers compounded in the fiber-reinforced plastic is the circumferential direction of the shaft wall.

4. A shaft wall construction method according to any one of claims 1 to 3, characterized in that the connecting material is attached without penetrating the inner wall and the outer wall.

5. 4. A shaft wall construction method according to claim 1, wherein the connecting members are arranged near the excavation periphery of the excavable area.

6. A method for constructing a shaft wall according to any one of claims 1 to 5, characterized in that the concrete filled between the outer wall and the inner wall is thinner than the concrete filled in the shaft wall body excluding the cut member of the shaft wall.

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