Method for constructing a tank containment dike and wall construction blocks

Abstract

In constructing a containment dike using block masonry, the aim is to minimize the increase in the weight of materials brought to the site, improve the efficiency of material transport, and simultaneously improve the efficiency of lifting operations for block masonry. [Solution] The method comprises a block arrangement step (C) in which a plurality of wall-forming blocks 20 made of half-precast concrete members, which are formed to have horizontally extending circumferential reinforcing bars 40, 62 embedded in them and formwork spaces 32, 52 penetrating in the vertical direction, are arranged horizontally in a circular shape on a foundation and stacked vertically; a circumferential reinforcing bar connection step (D) in which the circumferential reinforcing bars 40, 62 of the wall-forming blocks that are adjacent to each other in the horizontal direction are connected to each other; and a concrete pouring step (F) in which concrete is poured into the formwork spaces of the plurality of wall-forming blocks.

Description

Technical Field

[0001] The present invention relates to a method for constructing a liquid retaining dike for a tank and a wall component block.

Background Art

[0002] As a method for constructing a liquid retaining dike installed around the outer periphery of a tank for storing liquefied natural gas or the like, there is known a method of constructing the liquid retaining dike by stacking a plurality of precast concrete blocks (PCa blocks) manufactured in a factory side by side in the circumferential direction of the tank and laminating them in the vertical direction (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above prior art, in the construction of the liquid retaining dike by using PCa blocks, while the on-site casting of concrete is reduced, the PCa blocks are heavy, so a large crane is required. For this reason, the weight of the members carried into the site is large, and the workability of member transportation is poor. Further, in the above prior art, although the lifting load of the PCa blocks during block stacking is large, the area of the wall constructed by the PCa blocks is small, and the efficiency of the lifting work is poor.

[0005] In view of the above background, an object of the present invention is to suppress an increase in the weight of the members carried into the site in the construction of the liquid retaining dike by block stacking, improve the workability of member transportation, and also improve the efficiency of the lifting work of block stacking.

Means for Solving the Problems

[0006] To solve the above problems, one aspect of the present invention is a method for constructing a liquid containment dike (16) installed around the outside of a tank (14), comprising: a block arrangement step (C) in which a plurality of wall-constituting blocks (20) made of half-precast concrete members, which are formed to have horizontally extending circumferential reinforcing bars (40, 62) embedded in them and formwork spaces (32, 33, 52, 53) penetrating in the vertical direction, are arranged horizontally in a circular pattern on a foundation (12) and stacked vertically; a circumferential reinforcing bar connection step (D) in which the circumferential reinforcing bars of the wall-constituting blocks adjacent to each other in the horizontal direction are connected to each other; and a concrete pouring step (F) in which concrete is poured into the formwork spaces of the plurality of wall-constituting blocks.

[0007] According to this configuration, the weight of the components to be transported to the site is reduced compared to the use of precast concrete blocks, the workability of component transport is improved, and the efficiency of lifting operations for block stacking is also improved.

[0008] In the above embodiment, the wall component block has inner wall portions (34, 54) and outer wall portions (36, 56) that extend circumferentially at predetermined intervals in the radial direction, and connecting portions (38, 58) that extend radially and connect the inner wall portions and the outer wall portions to each other, and the inner wall portions, the outer wall portions and the connecting portions define the formwork space (32, 52), the circumferential reinforcing bars are embedded in the inner wall portions and the outer wall portions respectively, and each circumferential reinforcing bar may include extended reinforcing bars (40A, 62A) that extend horizontally outward from the horizontal ends of the inner wall portions and the outer wall portions respectively for connecting the circumferential reinforcing bars of adjacent wall component blocks in the horizontal direction.

[0009] According to this embodiment, in a circumferential arrangement of wall-forming blocks, the circumferential reinforcement can be arranged in a continuous annular shape in the circumferential direction of the wall-forming blocks, thereby improving the effectiveness of the circumferential reinforcement.

[0010] In the above embodiment, a formwork installation step is further provided between the circumferential reinforcement connection step and the concrete pouring step, the formwork installation step includes a step of removably attaching formwork members (110) extending between the outer wall portions of the wall constituent blocks adjacent to each other in the horizontal direction to the outside of the outer wall portions, the wall constituent blocks are arranged at predetermined intervals between adjacent wall constituent blocks in the horizontal direction, and have connecting plates (44, 74) extending horizontally outward from at least one horizontal end of the inner wall portion radially inward from the extending reinforcement portion, and the formwork space may include portions (33, 53) defined by the inner wall portion, the outer wall portion, the connecting plate and the formwork member between the wall constituent blocks adjacent to each other in the horizontal direction.

[0011] According to this embodiment, formwork spaces are defined between adjacent wall-forming blocks, and concrete is poured in place within these formwork spaces, thereby improving the strength of the containment dike.

[0012] In the above embodiment, the connecting plate may be provided at both horizontal ends of the inner wall portion and may have portions (44A, 44B, 74A, 74B) that overlap each other radially when adjacent to each other in the horizontal direction.

[0013] According to this embodiment, slurry leakage, where concrete leaks to the outside from between adjacent connecting plates in the horizontal direction, is suppressed.

[0014] In the above embodiment, the connecting plate may also serve as a mounting portion for the outer tank liner (18) which is positioned along the inside of the inner wall portion.

[0015] According to this embodiment, the special fittings for attaching the outer tank liner to the inside of the inner wall can be omitted.

[0016] In the above embodiment, the block placement step may include the step of passing vertical reinforcing bars (80) extending vertically from the foundation through the formwork space.

[0017] According to this embodiment, when using wall-forming blocks made of half-precast concrete members, the placement of vertical reinforcement bars can be easily and reliably carried out.

[0018] In the above embodiment, the block placement step may include the step of passing a vertical sheath pipe (82) extending vertically from the foundation through the formwork space.

[0019] According to this embodiment, when using wall-forming blocks made of half-precast concrete members, the arrangement of vertical sheath pipes can be easily and reliably performed.

[0020] In the above embodiment, the wall component block includes a circumferential sheath pipe (42) extending horizontally for a tensioning member (84) to pass through for introducing prestress, and comprises a general wall component block (30) constituting a general wall component, and a plurality of pilaster component blocks (50) constituting a pilaster component, each provided with a fixing device (66) for locking the end of the tensioning member to the wall component block, wherein the block arrangement step includes arranging the plurality of general wall component blocks in a continuous arc shape horizontally over a predetermined rotation angle range, connecting the circumferential sheath pipes of each general wall component block to each other, and arranging the plurality of pilaster component blocks at the end of the arrangement of the general wall component blocks, and further, after the concrete pouring step, a prestress introduction step may be included in which a tensioning member (84) is passed through the circumferential sheath pipe, tension is applied to the tensioning member, and the end of the tensioning member is locked to the wall component block by the fixing device.

[0021] According to this embodiment, the introduction of circumferential prestress to the wall constituent blocks can be carried out efficiently and reliably.

[0022] In order to solve the above problems, one aspect of the present invention is a wall construction block (20) composed of a half-precast concrete member, which has inner wall portions (34, 54) and outer wall portions (36, 56) that extend parallel to each other at a predetermined interval, and connecting portions (38, 58) that connect the inner wall portions and the outer wall portions to each other. The inner wall portions, the outer wall portions, and the connecting portions are formed to constitute formwork spaces (32, 52). Circumferential reinforcing bars (40, 62) are embedded in each of the inner wall portions and the outer wall portions. The circumferential reinforcing bars include extending bar portions (40A, 62A) that extend horizontally outward from both horizontal ends of each of the inner wall portions and the outer wall portions for connection with the circumferential reinforcing bars of other adjacent wall construction blocks. It has connection plates (44, 74) that extend horizontally outward from at least one end of the inner wall portion.

[0023] According to this aspect, the construction of a wall structure such as a liquid retaining dike can be carried out while suppressing an increase in the weight of the members carried into the site, and moreover, the reinforcement arrangement of the circumferential reinforcing bars can be appropriately carried out.

Effect of the Invention

[0024] According to the above aspect, the weight of the members carried into the site is suppressed, the workability of member transportation is good, and the efficiency of the lifting operation for block stacking can be improved.

Brief Description of the Drawings

[0025] [Figure 1] Schematic configuration diagram showing one embodiment of a liquefied natural gas storage facility equipped with a liquid retaining dike constructed by the construction method according to the present invention [Figure 2] Perspective view showing the state during the construction of the liquid retaining dike of this embodiment [Figure 3] Perspective view showing an example of a general wall portion block used for the liquid retaining dike of this embodiment [Figure 4] Plan view showing an example of the joint portion of the general wall portion block [Figure 5] Perspective view showing an example of a pilaster portion block used for the liquid retaining dike of this embodiment [Figure 6] Perspective view showing the anchoring section and reinforcement structure of the pilaster block. [Figure 7] Plan view showing an example of the arrangement of pilaster blocks used in the containment dike of this embodiment. [Figure 8] Plan view showing another example of a joint in a general wall block. [Modes for carrying out the invention]

[0026] Embodiments of the present invention will be described below with reference to the drawings.

[0027] As shown in Figure 1, the cryogenic storage facility for liquefied natural gas, etc. in this embodiment has a metal inner tank 14 for storing liquefied natural gas, etc., and a metal outer tank 18 positioned outside the inner tank 14, on a concrete foundation (base slab) 12 supported by a plurality of piles 10 driven into the ground. Furthermore, a containment dike 16 is constructed on the foundation 12 so as to surround the outer perimeter of the outer tank liner 18A that constitutes the side perimeter wall of the outer tank 18. The containment dike 16 extends along the outer surface of the outer tank liner 18A.

[0028] The inner tank 14 and the outer tank 18 are cylindrical tanks having a circular cross-sectional shape. The containment dike 16 is a cylindrical wall structure having a larger circular cross-sectional shape than the inner tank 14, and is installed around the outer perimeter of the outer tank 18.

[0029] As shown in Figure 2, the containment dike 16 is constructed in a cylindrical shape with a predetermined height by arranging multiple wall-forming blocks 20 horizontally (circumferentially) in a circular pattern on the foundation 12 and stacking them vertically in a predetermined number of layers. Each wall-forming block 20 is made of half-precast concrete (HPCa) material and is precast into a frame shape, leaving formwork spaces 32 and 52 for pouring cast-in-place concrete.

[0030] The wall-forming block 20 comprises two types of HPCa blocks: general wall blocks 30 that constitute the general wall portion of the containment dike 16, and pilaster blocks 50 that constitute the pilaster portion 64 of the containment dike 16. In the following description, the general wall blocks 30 and the pilaster blocks 50 may be collectively referred to as the wall-forming block 20.

[0031] As shown in Figure 3, the general wall block 30 has an inner wall portion 34 and an outer wall portion 36, each with an arc-shaped cross-section, that extend circumferentially (horizontally) at predetermined intervals in the radial direction of the containment dike 16. The general wall block 30 further has a plurality of connecting portions 38 that extend radially between the inner wall portion 34 and the outer wall portion 36, connecting the inner wall portion 34 and the outer wall portion 36 to each other. Each connecting portion 38 is provided at predetermined intervals in the circumferential direction of the inner wall portion 34 and the outer wall portion 36. The general wall block 30, with its inner wall portion 34, outer wall portion 36 and connecting portions 38, defines a formwork space 32 that penetrates vertically.

[0032] Each of the inner wall section 34 and the outer wall section 36 has multiple circumferential reinforcing bars 40 (see Figure 4) extending in the circumferential direction (horizontal direction) embedded in it during the precasting of the general wall section block 30. Each circumferential reinforcing bar 40 includes an extended reinforcing bar portion 40A that extends outward from both horizontal ends of the inner wall section 34 and the outer wall section 36, respectively, for connection with the circumferential reinforcing bars 40 of the horizontally adjacent general wall section block 30 or the circumferential reinforcing bars 62 (see Figure 7) of the pilaster section block 50.

[0033] The general wall block 30 has multiple circumferential sheath pipes 42 that extend circumferentially through the connecting portion 38 and are embedded in the general wall block 30 during precasting. In this embodiment, multiple circumferential sheath pipes 42 are provided in each general wall block 30, arranged vertically. The circumferential sheath pipes 42 include extension pipe portions 42A that extend outward from each of the connecting portions 38 located on the horizontal outer end side of the general wall block 30, for connection with the circumferential sheath pipes 42 of adjacent general wall blocks 30 in the horizontal direction.

[0034] Metal connecting plates 44 are fixed to both horizontal ends of the inner wall portion 34, radially inward from the extended reinforcing bar portion 40A, and including portions that extend outward from the corresponding ends. Each connecting plate 44 is joined to the inner wall portion 34 during the precasting of the general wall portion block 30 such that its radially inward surface is flush with the radially inward surface of the inner wall portion 34. The connecting plates 44 integrally have studs 45 (see Figures 4 and 7) that are embedded in the inner wall portion 34 during the precasting of the general wall portion block 30 in order to improve the joint strength with the inner wall portion 34.

[0035] Each connecting plate 44 has a free end with a portion 44A that overlaps radially with adjacent connecting plates in the horizontal direction (hereinafter referred to as the overlap portion). Of the connecting plates 44 located at both ends of the inner wall portion 34 in the horizontal direction, the overlap portion 44A of one of the connecting plates 44 (the connecting plate 44 on the right in Figure 3) is offset radially outward by a dimension equivalent to the thickness of the connecting plate 44. As a result, even in the portion of the overlap portion 44A, the radially inner surface is flush with the radially inner surface of the inner wall portion 34.

[0036] Each of the connecting plates 44 has an overlapping portion 44B at its upper and lower ends, where adjacent plates in the vertical direction (up and down direction) overlap radially (hereinafter referred to as an overlap). The overlapping portion 44B at the upper end is offset radially outward by a dimension equivalent to the thickness of the connecting plate 44, such that its radially inner surface is flush with the radially inner surface of the inner wall portion 34.

[0037] A metal strip-shaped outer tank liner mounting plate 46, extending vertically, is joined to the radially inner surface of the inner wall portion 34 at horizontal positions corresponding to each connecting portion 38 during the precasting of the general wall portion block 30. This joining is set so that the radially inner surface of the outer tank liner mounting plate 46 is flush with the radially inner surface of the inner wall portion 34.

[0038] As shown in Figure 5, the pilaster block 50 has an inner wall portion 54 and an outer wall portion 56 with an arc-shaped cross-section that extend circumferentially (horizontally) at predetermined intervals in the radial direction of the containment dike 16. The pilaster block 50 further has a plurality of connecting portions 58 that extend radially between the inner wall portion 54 and the outer wall portion 56 and connect the inner wall portion 54 and the outer wall portion 56 to each other. Each connecting portion 58 is provided at predetermined intervals in the circumferential direction of the inner wall portion 54 and the outer wall portion 56. The circumferential intermediate portion of the outer wall portion 56 constitutes a pilaster outer wall portion 60 radially outward from the outer wall portion 56. The pilaster block 50 defines a formwork space 52 that penetrates vertically through the inner wall portion 54, the outer wall portion 56 and the connecting portions 58.

[0039] Each of the inner wall section 54 and the outer wall section 56 has multiple circumferential reinforcing bars 62 (see Figure 7) extending horizontally (circumferentially) embedded in it during the precasting of the pilaster section block 50. Each circumferential reinforcing bar 62 includes an extended reinforcing bar portion 62A that extends outward from both horizontal ends of the inner wall section 54 and the outer wall section 56, respectively, for connection with the circumferential reinforcing bars 40 of the adjacent general wall section block 30 in the horizontal direction.

[0040] The pilaster block 50 has a pilaster portion 64 that extends radially outward from the outer wall portion 56, including the pilaster outer wall portion 60. Multiple anchoring devices 66 are attached to each of the circumferential sides of the pilaster portion 64.

[0041] In the pilaster section block 50, multiple upper and lower circumferential sheath pipes 68 made of resin or the like are embedded during precasting, so as to penetrate horizontally through the connecting section 58. The pilaster section block 50 is configured to guide one end 68A of a predetermined number of the multiple circumferential sheath pipes 68 to anchoring devices 66 provided on both sides of the pilaster section 64, as shown in Figure 6. The other numbers of the multiple circumferential sheath pipes 68 extend horizontally through the pilaster section block 50, as shown in Figure 2.

[0042] The circumferential sheath pipe 68 includes an extended pipe section 68B that extends outward from each of the connecting sections 58 located on the horizontal outer end side of the pilaster section block 50 for connection with the circumferential sheath pipes 42 of the horizontally adjacent general wall section blocks 30.

[0043] As shown in Figure 7, spiral reinforcing bars 70 surrounding the ends 68A (terminals) of the circumferential sheath pipes 68 and their vicinity are embedded on both sides of the pilaster section 64 of the pilaster section block 50 during the precasting process. In addition, reinforcing bars 72 extending along the outer wall of the pilaster section 64 are embedded during the precasting process of the pilaster section block 50.

[0044] Metal connecting plates 74 are fixed to both horizontal ends of the inner wall portion 54, radially inward from the extended reinforcing bar portion 62A, and including portions that extend outward from the corresponding ends. Each connecting plate 74 is joined to the inner wall portion 54 during the precasting of the pilaster block 50 such that its radially inward surface is flush with the radially inward surface of the inner wall portion 54. The connecting plates 74 integrally have studs 75 (see Figure 7) that are embedded in the inner wall portion 54 during the precasting of the pilaster block 50 in order to improve the joint strength with the inner wall portion 54.

[0045] Each connecting plate 74 has a portion (hereinafter referred to as the overlap portion) 74A at its free end that overlaps radially with the overlap portion 44A of the connecting plates 44 of the horizontally adjacent general wall blocks 30. Of the connecting plates 74 at both ends of the inner wall 54 in the horizontal direction, the overlap portion 74A of one of the connecting plates 74 (the connecting plate 74 on the right in Figure 7) is offset radially outward by a dimension equivalent to the thickness of the connecting plate 74. As a result, even in the overlap portions 44A and 74A, the radially inner surface is flush with the radially inner surface of the inner wall sections 34 and 54.

[0046] Each connecting plate 74 has an overlapping portion (hereinafter referred to as "overlap") 74B at its upper and lower ends, where adjacent connecting plates in the vertical direction (up and down direction) overlap each other radially. The overlapping portion 74B at the upper end is offset radially outward by a dimension equivalent to the thickness of the connecting plate 74, such that its radially inner surface is flush with the radially inner surface of the inner wall portion 54.

[0047] A metal strip-shaped outer tank liner mounting plate 76, extending vertically, is joined to the radially inner surface of the inner wall portion 54 at horizontal positions corresponding to each connecting portion 58 during the precasting of the pilaster portion block 50. This joining is set so that the radially inner surface of the outer tank liner mounting plate 76 is flush with the radially inner surface of the inner wall portion 54.

[0048] Next, referring to Figures 1 to 7, we will sequentially explain the steps (A) to (H) that are performed in the implementation of the method for constructing the containment dike 16.

[0049] (A) Foundation creation process First, as shown in Figure 1, multiple piles 10 are driven into the ground. After the pile driving is completed, a foundation 12 is created on top of the piles 10 using cast-in-place concrete. In creating this foundation 12, as shown in Figure 2, the lower parts of the vertical reinforcing bars 80 and vertical sheath pipes 82, which extend in the vertical direction, are embedded in the lower part of the foundation 12. The lower part of the vertical sheath pipe 82, which is bent into a U shape, is embedded in the foundation 12.

[0050] Although partially omitted in the illustration, multiple vertical reinforcing bars 80 are provided for each wall-forming block 20. Although partially omitted in the illustration, at least one vertical sheath pipe 82 is provided for each wall-forming block 20.

[0051] The vertical reinforcing bars 80 and vertical sheath pipes 82 each have a predetermined length that is less than the total height of the containment dike 16, and are extended as the general wall blocks 30 and pilaster blocks 50 are laid, until their length is approximately equal to the total height of the containment dike 16. Alternatively, the vertical reinforcing bars 80 and vertical sheath pipes 82 may have a length that is approximately equal to the total height of the containment dike 16 from the start.

[0052] (B) Scaffolding construction process After the foundation work is completed, scaffolding 100 will be assembled around the outer perimeter of the containment dike 16.

[0053] In the method for constructing the containment dike 16 of this embodiment, the scaffolding 100 is provided only in the area surrounding the outer perimeter of the containment dike 16, and scaffolding does not need to be provided on the inner perimeter side of the containment dike 16. In this case, the construction of the outer tank liner 18A and the inner tank liner 14A of the inner tank 14 (see Figure 1), which are provided along the inner wall of the containment dike 16, can be carried out in parallel with the construction of the containment dike 16 without being hindered by the scaffolding 100 for the construction of the containment dike 16. In other words, once the containment dike 16 has been constructed to a certain height, internal mechanical work such as the inner tank liner 14A and outer tank liner 18A can be carried out. This makes it possible to shorten the construction period of the cryogenic storage facility for liquefied natural gas.

[0054] In the construction of the outer tank liner 18A, the outer tank liner 18A is fixed to the inner walls of the general wall block 30 and the pilaster block 50 using the connecting plates 44, 74 and outer tank liner mounting plates 46, 76 that are pre-provided on the general wall block 30 and the pilaster block 50.

[0055] This reduces the construction time of the outer tank liner 18A. In addition, it eliminates the need for special fittings to attach the outer tank liner 18A to the inner walls 34 and 54 of the general wall block 30 and the pilaster block 50.

[0056] (C) Block placement process Next, multiple general wall blocks 30 and pilaster blocks 50, which are HPCa blocks, are arranged horizontally in a circular pattern on the base 12 to create the first layer of a circular arrangement. The pilaster blocks are placed at four locations in the circumferential direction at equal intervals with a 90-degree rotation angle. Multiple general wall blocks 30 are placed continuously between adjacent pilaster blocks 50.

[0057] In other words, in the block arrangement process, multiple general wall blocks 30 are arranged in a continuous arc shape horizontally over a predetermined rotation angle range close to 90 degrees, and multiple pilaster blocks 50 are placed at the ends of the arc-shaped arrangement of general wall blocks 30.

[0058] When arranging the general wall blocks 30 and pilaster blocks 50, the vertical reinforcing bars 80 and vertical sheath pipes 82 are passed through the formwork spaces 32 and 52 vertically. This makes it easy and reliable to arrange the vertical reinforcing bars 80 and vertical sheath pipes 82.

[0059] In the block arrangement process, as shown in Figure 4, the extension pipe sections 42A of the circumferential sheath pipes 42 of adjacent general wall blocks 30 in the horizontal direction are connected to each other by connecting pipes 43 made of resin or the like. Also, as shown in Figure 7, the extension pipe sections 42A of the circumferential sheath pipes 42 of adjacent general wall blocks 30 in the horizontal direction and the extension pipe sections 68B of the circumferential sheath pipes 68 of the pilaster block 50 are connected to each other by connecting pipes 43 made of resin or the like.

[0060] As a result, in the annular arrangement of the general wall block 30 and the pilaster block 50, the circumferential sheath tube 42 is arranged in a continuous annular shape in the circumferential direction of the general wall block 30 and the pilaster block 50.

[0061] This makes it possible to easily and reliably introduce circumferential stress to the wall component block 20 by passing PC steel wire (tensioning material) 84 (see Figures 3 and 6) through the circumferential sheath pipe 42.

[0062] (D) Circumferential reinforcement connection process Next, as shown in Figure 4, the extended reinforcing bars 40A of the circumferential reinforcing bars 40 of adjacent general wall blocks 30 in the horizontal direction are connected to each other using mechanical reinforcing bar connectors 41. Furthermore, as shown in Figure 7, the extended reinforcing bars 40A of the circumferential reinforcing bars 40 of adjacent general wall blocks 30 in the horizontal direction and the extended reinforcing bars 62A of the circumferential reinforcing bars 62 of the pilaster block 50 are connected to each other using mechanical reinforcing bar connectors 41.

[0063] As a result, in the circumferential arrangement, or in other words, the annular arrangement, of the general wall blocks 30 and pilaster blocks 50, the circumferential reinforcement bars 40 are arranged in a continuous annular shape in the circumferential direction of the wall constituent blocks 20, thereby improving the effectiveness of the circumferential reinforcement bars 40.

[0064] In the wall-forming blocks 20, the radially inward side of the block connection portion where adjacent blocks are connected horizontally is closed by connecting plates 44 and 74, but the radially outward side, that is, the side where the scaffolding 100 is located, is open. As a result, the work of connecting the circumferential reinforcing bars 40 and circumferential sheath pipes 42 can be carried out efficiently from the radially outward side of the block connection portion using the scaffolding 100, without being obstructed by the connecting plates 44 and 74, etc.

[0065] (E) Formwork installation process Next, as shown in Figures 4 and 7, formwork members 110 are attached to the connection points of horizontally adjacent general wall blocks 30 and to the connection points between horizontally adjacent general wall blocks 30 and pilaster blocks 50. The formwork members 110 are flat plates made of wood or the like and are detachably fixed to the radially outward surfaces of the outer wall portion 36 of the general wall block 30 and the outer wall portion 56 of the pilaster block 50 using embedded screws or the like.

[0066] As shown in Figure 4, the formwork member 110 extends between the outer wall portions 36 of the general wall blocks 30 that are adjacent to each other in the horizontal direction. As a result, a formwork space 33 equivalent to the formwork space 32 is defined between the horizontally adjacent general wall blocks 30 by the inner wall portion 34, the outer wall portion 36, the connecting portion 38, the connecting plate 44, and the formwork member 110.

[0067] Furthermore, as shown in Figure 7, the formwork member 110 extends between the outer wall portion 36 of the general wall portion 30 and the outer wall portion 56 of the pilaster portion block 50 in order to close the gap between the outer wall portion 36 of the general wall portion block 30 and the outer wall portion 56 of the pilaster portion block 50 that are adjacent to each other in the horizontal direction. As a result, a formwork space 53 equivalent to the formwork space 52 is defined between the horizontally adjacent general wall portion block 30 and pilaster portion block 50 by the inner wall portions 34, 54, the outer wall portions 36, 56, the connecting portions 38, 58, the connecting plates 44, 74 and the formwork member 110.

[0068] Then, the annular arrangement of general wall blocks 30 and pilaster blocks 50 are stacked vertically in a predetermined number of layers until the height reaches approximately equal to the total height of the containment dike 16. This block stacking is a grid-like block stacking in which, in each layer, the boundary lines (joint lines) of adjacent general wall blocks 30 and pilaster blocks 50 in the horizontal direction are aligned in straight lines both vertically and horizontally.

[0069] (F) Concrete pouring process After the construction of the wall-forming blocks 20 for the number of layers required to build a containment dike 16 of a predetermined height, and the installation of the formwork members 110 are completed, concrete is poured in place into each of the formwork spaces 32, 33, 52, and 53 from above the block stacking. This concrete pouring may be carried out in multiple stages, with each stage of block stacking being completed.

[0070] In the formwork spaces 32, 33, 52, and 53, the hardened concrete connects the upper and lower wall component blocks 20 to each other. In addition, in the formwork spaces 33 and 53, the hardened concrete connects the horizontal wall component blocks 20 to each other.

[0071] The formwork member 110 is removed after the concrete in the formwork spaces 33 and 53 has hardened.

[0072] (G) Prestress introduction process After the cast-in-place concrete has hardened in the formwork spaces 32, 33, 52, and 53, PC steel wires 84 are passed through the circumferential sheath pipes 42 and 68 from the end 68A of the circumferential sheath pipe 68 of the pilaster block 50. Then, with tension applied to the PC steel wires 84, both ends of the PC steel wires 84 are secured to the pilaster block 50 by anchoring devices 66, as shown in Figure 6. This introduces circumferential (horizontal) prestress to the wall component block 20.

[0073] Furthermore, after the wall block 20 is completed, a PC steel wire (tensioning member) 86 (see Figure 2) is passed through the U-shaped vertical sheath pipe 82 from the top of one end to the top of the other. Then, with tension applied to the PC steel wire 86, both upper ends of the PC steel wire 86 are secured to the uppermost wall block 20 using a fixing device (not shown). This introduces vertical prestress to the wall block 20.

[0074] The PC steel wire 84 is arranged to encircle the containment dike 16, and in this embodiment, it is divided into two sections with a 180-degree rotation angle. Each of the two divided PC steel wires 84 is secured by a fixing device 66 to each of two pilaster section blocks 50 that are spaced 180 degrees apart from each other, out of four pilaster section blocks 50 that are spaced 90 degrees apart. Each of these PC steel wires 84 passes through the pilaster section block 50 located in the middle of the two pilaster section blocks 50 that are spaced 180 degrees apart, as shown in Figure 2. The two divided PC steel wires 84 are arranged with a 90-degree phase difference in the circumferential direction between them in each upper and lower section.

[0075] (H) Scaffolding removal process After prestressing is implemented and the containment dike 16 is completed, the scaffolding 100 will be removed.

[0076] As explained above, the method for constructing the containment dike 16 of this embodiment is composed of general wall blocks 30 and pilaster blocks 50 made of half-precast concrete members. Therefore, compared to using PCa blocks, the weight of the members is reduced, the workability of transporting the members is improved, and the efficiency of lifting work for stacking the blocks is also improved.

[0077] Although the present invention has been described above in terms of preferred embodiments, as will be easily understood by those skilled in the art, the present invention is not limited to these embodiments and can be modified as appropriate without departing from the spirit of the invention.

[0078] For example, the connecting plates 44 and 74 may not include overlaps 44A, 44B, 74A, and 74B, and may be butt-jointed as shown in Figure 8, with the butt joint sealed by a sealing member 78 or adhesive tape to prevent slag leakage. Alternatively, the connecting plates 44 and 74 may be provided only at one end of the general wall block 30 or the pilaster block 50.

[0079] The PC steel wire 84 is not limited to being divided into two sections, and may be undivided or divided into two or more sections depending on the circumference of the containment dike 16. The general wall section block 30 and the pilaster section block 50 are not limited to being arc-shaped, and may be straight.

[0080] The containment dike constructed by the construction method according to the present invention is not limited to containment dikes for cylindrical tanks, but can also be applied to containment dikes for spherical tanks. Furthermore, the construction method and wall component blocks according to the present invention can also be applied to containment dike cylindrical silos and cylindrical reinforced concrete structures.

[0081] Furthermore, not all of the components shown in the above embodiments are necessarily essential, and they can be appropriately selected and omitted as long as they do not deviate from the spirit of the present invention. [Explanation of Symbols]

[0082] 12: Basics 14: Inner tank 14A: Inner tank liner 16: Liquid dike 18: Outer tank 18A: Outer tank liner 20: Wall construction blocks 30: General wall block 32: Formwork space 33: Formwork space 34:Inner wall 36:Outer wall 38:Connection part 40: Circumferential reinforcement 40A: Extensor muscle 42: Circumferential sheath tube 42A: Extension pipe section 43: Connecting pipe 44: Connecting plate 44A: Overlapping portion (overlap allowance) 44B: Overlapping portion (overlap allowance) 50: Pilastar section block 52: Formwork space 53: Formwork space 54:Inner wall 56:Outer wall 58:Connection part 62: Circumferential reinforcement 62A: Extensor muscle 64: Pilastar section 66: Fixing device 68: Circumferential sheath tube 68A: End 68B: Extension pipe section 70: Reinforcement bars 72: Reinforcement bars 74: Connection plate 74A: Overlapping portion (overlap allowance) 74B: Overlapping portion (overlap margin) 75: Stud 76: Outer tank liner mounting plate 80: Vertical reinforcement bars 82: Vertical sheath pipe 84: Tensioning material (PC steel wire) 100: Scaffolding 110: Formwork component

Claims

1. A method for constructing a containment dike installed around the outer perimeter of a tank, A block arrangement process involves arranging multiple wall-forming blocks, each made of half-precast concrete members with horizontally extending circumferential reinforcing bars embedded and formed to create a formwork space that penetrates vertically, horizontally in a circular pattern on the foundation and stacking them vertically. A circumferential reinforcement connection step involves connecting the circumferential reinforcement bars of the wall constituent blocks that are adjacent to each other in the horizontal direction, A method for constructing a liquid containment dike, comprising a concrete pouring step of pouring concrete into the formwork spaces of the plurality of wall constituent blocks.

2. The wall-forming block has an inner wall portion and an outer wall portion that extend circumferentially at a predetermined distance in the radial direction, and a connecting portion that extends radially and connects the inner wall portion and the outer wall portion to each other, and the inner wall portion, the outer wall portion and the connecting portion define the formwork space. The circumferential reinforcing bars are embedded in the inner wall portion and the outer wall portion, respectively. The method for constructing a flood control dike according to claim 1, wherein each circumferential reinforcing bar includes an extended reinforcing bar that extends horizontally outward from both horizontal ends of the inner wall portion and the outer wall portion, respectively, for the purpose of connecting the circumferential reinforcing bars of adjacent wall constituent blocks in the horizontal direction.

3. Between the circumferential reinforcement connection step and the concrete pouring step, there is further a formwork installation step. The formwork installation step includes the step of removably attaching formwork members that extend between the outer wall portions of the wall constituent blocks that are adjacent to each other in the horizontal direction to the outside of the outer wall portions, The wall component blocks are arranged at a predetermined interval between adjacent wall component blocks in the horizontal direction, and have connecting plates that extend horizontally outward from at least one horizontal end of the inner wall portion, radially inward from the extending reinforcement portion. The method for constructing a liquid containment dike according to claim 2, wherein the formwork space includes a portion defined by the inner wall portion, the outer wall portion, the connecting plate, and the formwork member between the wall constituent blocks adjacent to each other in the horizontal direction.

4. The method for constructing a liquid containment dike according to claim 3, wherein the connecting plates are provided at both horizontal ends of the inner wall portion and have portions that overlap each other radially when adjacent to each other in the horizontal direction.

5. The method for constructing a liquid containment dike according to claim 3 or 4, wherein the connecting plate also serves as an attachment point for an outer tank liner arranged along the inside of the inner wall portion.

6. The method for constructing a liquid containment dike according to any one of claims 1 to 4, wherein the block placement step includes passing vertical reinforcing bars extending vertically from the foundation through the formwork space.

7. The method for constructing a liquid containment dike according to any one of claims 1 to 4, wherein the block placement step includes passing a vertical sheath pipe extending vertically from the foundation through the formwork space.

8. The wall component block includes a circumferential sheath pipe extending horizontally for a tensioning member to pass through for introducing prestress, and comprises a general wall component block that constitutes a general wall, and a plurality of pilaster component blocks that constitute a pilaster, each provided with a fixing device for engaging the ends of the tensioning member with the wall component block. The block arrangement step includes arranging a plurality of general wall blocks in a continuous arc shape in the horizontal direction over a predetermined rotation angle range, connecting the circumferential sheath tubes of each general wall block to one another, and arranging a plurality of pilaster blocks at the ends of the arrangement of the general wall blocks. Furthermore, the method for constructing a liquid containment dike according to any one of claims 1 to 4, comprising a prestress introduction step after the concrete pouring step, in which the tensioning material is passed through the circumferential sheath pipe, tension is applied to the tensioning material, and the ends of the tensioning material are secured to the wall constituent blocks with the anchoring device.

9. A wall structure block composed of half-precast concrete members, It has an inner wall portion and an outer wall portion that extend parallel to each other at a predetermined interval, and a connecting portion that connects the inner wall portion and the outer wall portion to each other, and is molded to form a formwork space with the inner wall portion, the outer wall portion and the connecting portion. Circumferential reinforcing bars are embedded in each of the inner and outer wall portions. The circumferential reinforcement includes extensions that extend horizontally outward from both horizontal ends of the inner wall and the outer wall, respectively, for connection with the circumferential reinforcement of other adjacent wall component blocks. A wall component block having a connecting plate extending horizontally outward from at least one end of the inner wall portion.

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