Wall construction method
The method of constructing tank walls using precast members with pre-formed barrier layers at a factory and on-site joint formation addresses safety concerns in high-altitude work, improving quality and reducing construction time and costs while maintaining structural integrity and insulation performance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KAJIMA CORP
- Filing Date
- 2023-02-20
- Publication Date
- 2026-07-07
AI Technical Summary
The construction of multi-layered side walls in large tanks, such as those for storing low-temperature liquids, involves significant high-altitude work, posing safety management challenges due to the complexity and height of the structure.
A method for constructing a wall structure using precast concrete members with a pre-formed barrier layer, followed by a cooling layer and inner tank, where the barrier layer is inspected and formed at a factory before installation, reducing high-altitude work by forming it only in joint sections during on-site assembly.
This approach enhances safety by minimizing high-altitude work, improving quality control, and reducing construction time and costs while ensuring liquid-tightness and airtightness, with the added benefit of smoother surfaces for insulation panels, thereby enhancing overall construction efficiency and safety.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a method for constructing a wall structure.
Background Art
[0002] Conventionally, as a technology in this field, a tank described in Patent Document 1 below is known. This tank is for storing a low-temperature liquid such as LNG, and the side wall of the tank has a multi-layer structure including a liquid retaining dike, an outer tank, an inner tank, a heat insulation layer, etc.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] The side wall of this type of tank has a height of, for example, several tens of meters. Therefore, the construction of the plurality of layers as described above included in the side wall of the tank often involves a lot of high-altitude work, and for this reason, the burden of safety management during construction is large. An object of the present invention is to provide a method for constructing a wall structure that improves the safety of construction.
Means for Solving the Problems
[0005] The gist of the present invention is as follows.
[0006] [1] A method for constructing a wall for a tank comprising: a concrete structure formed including precast members arranged in the direction of the wall surface; a barrier layer provided inside the concrete structure and having liquid-tightness and airtightness; a cooling layer provided inside the barrier layer; and an inner tank provided inside the cooling layer, the method comprising: a precast member preparation step of preparing the precast members having the barrier layer formed on their surface; a precast member installation step of installing the precast members having the barrier layer formed on their surface at the planned construction location of the wall; and a joint treatment step of forming the barrier layer in the joints between adjacent precast members at the planned construction location.
[0007] [2] The method for constructing a wall according to [1], wherein in the joint treatment step, an embedded formwork for pouring filler concrete into the joint filler between the precast members is installed in the joint filler, and the barrier layer is formed in advance on the surface of the embedded formwork.
[0008] [3] The method for constructing a wall according to [1], wherein in the joint treatment step, a metal embedded formwork for pouring filler concrete into the joint filler between the precast members is installed in the joint filler, and the metal embedded formwork constitutes the barrier layer in the joint.
[0009] [4] The method for constructing a wall according to any one of [1] to [3], wherein in the precast member preparation step, the barrier layer is formed on the surface of the precast member by coating or spraying while the precast member is laid flat.
[0010] [5] A wall construction method according to any one of [1] to [4], further comprising a barrier layer inspection step of inspecting the barrier layer on the surface of the precast member before the precast member installation step. [Effects of the Invention]
[0011] According to the present invention, a method for constructing a wall that improves construction safety can be provided. [Brief explanation of the drawing]
[0012] [Figure 1] This is a partially broken perspective view of a ground tank to which the wall construction method of this embodiment is applied. [Figure 2] This is a vertical cross-sectional view showing a magnified portion of the side wall of the above-ground tank. [Figure 3] This is a flowchart of the wall construction method according to this embodiment. [Figure 4] (a) and (b) are diagrams showing PCa blocks in the precast member preparation process. [Figure 5] (a) is a horizontal cross-sectional view of the vicinity of the joint between PCa blocks during the precast member installation process, and (b) is a perspective view showing the planned construction location during the precast member installation process as seen from inside the tank. [Figure 6] (a) is a horizontal cross-sectional view of the area near the joint during the joint treatment process, and (b) is a perspective view showing the planned construction location during the joint treatment process as seen from inside the tank. [Figure 7] This is a horizontal cross-sectional view near the joint between PCa blocks during the precast member installation process of the second embodiment. [Figure 8] (a) is a horizontal cross-sectional view showing an example of the treatment of the boundary between the buried formwork and the PCa block, and (b) is a horizontal cross-sectional view showing another example of the same treatment. [Figure 9] This is a horizontal cross-sectional view of the vicinity of the joint between PCa blocks during the precast member installation process of the third embodiment. [Figure 10] (a) is a vertical cross-sectional view showing a modified concrete structure, and (b) is a cross-sectional view showing the embedded formwork for constructing that concrete structure. [Modes for carrying out the invention]
[0013] Hereinafter, embodiments of the wall construction method according to the present invention will be described in detail with reference to the drawings.
[0014] [First Embodiment] A method for constructing a wall body according to the first embodiment will be described. FIG. 1 is a partially broken perspective view of a ground tank 1 to which the wall body construction method of the present embodiment is applied. The tank 1 is a cylindrical flat-bottomed cryogenic PC tank, for example, for storing cryogenic liquids such as LNG and ammonia. As shown in FIG. 1, the tank 1 includes a circular bottom plate 3, a cylindrical side wall 5 (wall body) rising vertically from the circumferential edge of the bottom plate 3, and a roof portion 7 closing the upper end opening of the side wall 5. The side wall 5 is provided, for example, at a height of about 40 m. FIG. 2 is a vertical cross-sectional view showing an enlarged part of the side wall 5 of the tank 1 (part II in FIG. 1). As shown in FIG. 2, the side wall 5 is composed of a concrete body 11, a barrier layer 13, a cold insulation layer 15, and a metal inner tank 17 laminated in order from the outside to the inside of the tank 1.
[0015] The concrete body 11 is composed of a plurality of precast concrete blocks 12 (hereinafter referred to as "PCa blocks 12") two-dimensionally arranged in the wall surface direction (circumferential direction and vertical direction) of the side wall 5 and joined to each other with a predetermined joint structure. The thickness of the concrete body 11 is, for example, 0.5 to 1.0 m.
[0016] The barrier layer 13 is provided on the inner surface of the concrete body 11 and has liquid tightness and air tightness. In case the stored liquid leaks from the metal inner tank 17, the leaked liquid can reach the barrier layer 13 through the cold insulation layer 15, but the liquid tightness of the barrier layer 13 prevents the leakage of the liquid to the outside. Also, due to the air tightness between the metal inner tank 17 and the barrier layer 13, the space between the metal inner tank 17 and the barrier layer 13 (the space of the cold insulation layer 15) is made an airtight space, and the airtight space is nitrogen-substituted. Thereby, the gas generated in the airtight space due to the vaporization of the leaked liquid can be detected sensitively, and the leakage of the stored liquid from the metal inner tank 17 can be detected by detecting the gas.
[0017] The barrier layer 13 is composed of a resin material R sprayed or applied (e.g., brush painting) on the inner surface of the concrete body 11. The resin material R is selected in consideration of the aforementioned airtightness and liquid tightness, followability to the behavior of the concrete body 11 (e.g., crack followability), resistance to chemical action with the stored liquid, etc. The resin material R is, for example, a polymer-based polyurethane resin, and the thickness of the barrier layer 13 is, for example, about 2 to 5 mm.
[0018] The cold insulation layer 15 is composed of a plurality of cold insulation panels 16 two-dimensionally arranged in the wall surface direction (circumferential direction and vertical direction) of the side wall 5. Each cold insulation panel 16 is bolted to the inner surface of the concrete body 11 with the barrier layer 13 sandwiched therebetween, and a filler 15t such as glass wool is filled between adjacent cold insulation panels 16. In order to enable the bolting of the cold insulation panel 16 as described above, a bottomed insert nut 19a is embedded in the PCa block 12. The material of the cold insulation panel 16 is, for example, polyurethane foam or perlite concrete panel, and the thickness of the cold insulation layer 15 is, for example, 10 to 20 cm.
[0019] The metal inner tank 17 is composed of a plurality of metal plates 18 two-dimensionally arranged in the wall surface direction (circumferential direction and vertical direction) of the side wall 5. Each metal plate 18 is bolted to the inner wall surface of the concrete body 11 with the cold insulation layer 15 and the barrier layer 13 sandwiched therebetween. Both ends of adjacent metal plates 18 are overlapped and welded in the plate thickness direction. In order to enable the bolting of the metal plate 18 as described above, a bottomed insert nut 19b is embedded in the PCa block 12. The metal inner tank 17 has liquid tightness and accommodates the stored liquid in the inner space. Also, the metal inner tank 17 has airtightness as described above. The material of the metal plate 18 is, for example, stainless steel, and the thickness of the metal plate 18 is, for example, 2 mm.
[0020] Next, a method for constructing the wall body to build the above-mentioned side wall 5 will be described. As shown in Figure 3, this wall body construction method comprises a precast member preparation step S201, a barrier layer inspection step S203, a precast member installation step S205, a joint treatment step S207, a joint inspection step S209, a cold insulation layer construction step S211, and a metal inner tank construction step S213. Each step will be described below with reference to Figures 2 to 6.
[0021] (Precast member preparation process S201) In the precast member preparation process S201, PCa blocks 12 for constructing the concrete structure 11 (Figure 2) are prepared. A barrier layer 13 is formed in advance on the surface of the PCa blocks 12 prepared here. These PCa blocks 12 are manufactured in advance at a factory separate from the tank 1 construction site and then transported to the tank 1 construction site.
[0022] Specifically, as shown in Figure 4, the PCa block 12 is manufactured in the factory using a known method. The PCa block 12 is slightly curved to correspond to the curve of the side wall 5. The PCa block 12 has reinforcing bars 12r protruding from its end face and the aforementioned insert nuts 19a, 19b (Figure 2) embedded in it. The manufactured PCa block 12 is placed on a predetermined base B and laid flat. Here, the PCa block 12 is placed in a position where the surface 12a of the PCa block 12 corresponding to the inner surface of the concrete structure 11 is approximately horizontal and facing upward.
[0023] With the PCa block 12 laid flat in this manner, the resin material R of the barrier layer 13 is sprayed onto the entire surface 12a, forming the barrier layer 13 on the surface 12a. Strictly speaking, what is formed here is only a portion of the barrier layer 13 that exists on the PCa block 12, so if distinguishing it, it is called the "barrier layer 13h". Subsequently, as the sprayed resin material R hardens over time, the PCa block 12 is completed with the barrier layer 13h formed on the surface 12a, as shown in Figure 4(b). Since the PCa block 12 has flanges of insert nuts 19a and 19b (Figure 2) along the surface 12a, the barrier layer 13h is formed so as to straddle the boundary between the flange and the concrete portion of the PCa block 12. In this precast member preparation step S201, the barrier layer 13h may also be formed by applying the resin material R to the surface 12a (for example, by brush application).
[0024] The precast member preparation process S201 includes a barrier layer inspection process S203. In the barrier layer inspection process S203, a quality confirmation inspection is performed on the barrier layer 13h on the surface 12a of the PCa block 12. As mentioned above, the barrier layer 13 is required to be liquid-tight and airtight, so here, a visual inspection of the barrier layer 13h and a pinhole test using a pinhole flaw detector are performed. This barrier layer inspection process S203 is performed with the PCa block 12 lying flat, similar to when the resin material R is sprayed (Figure 4(a)). After the barrier layer inspection process S203, the PCa block 12 is transported from the factory to the tank 1 construction site. That is, PCa block 12 with the barrier layer 13h formed on its surface is prepared at the tank 1 construction site.
[0025] (Precast member installation process S205) Figure 5(a) is a horizontal cross-sectional view of the vicinity of the joint between circumferentially adjacent PCa blocks 12, 12, which are installed at the planned construction position 6 of the side wall 5 during the precast member installation process S205. In Figure 5(a), the upper part is the inside of the tank and the lower part is the outside of the tank. Figure 5(b) is a perspective view of the planned construction position 6 as seen from inside the tank during the precast member installation process S205. In Figure 5(b), the foreground is the inside of the tank and the background is the outside of the tank.
[0026] In the precast member installation process S205, as shown in Figures 5(a) and 5(b), multiple PCa blocks 12 prepared in the precast member preparation process S201 are installed at the planned construction locations 6 of the side wall 5. Subsequently, adjacent PCa blocks 12, 12 in the circumferential or vertical direction are joined together with a predetermined joint structure including infill concrete 21, forming a joint 23. Furthermore, the PCa blocks 12, 12 are firmly joined together by applying prestress through tensioning of separately installed PC steel members (not shown).
[0027] An example of how to form the joint section 23 is as follows. When the PCa blocks 12 are placed at the planned construction location 6, a joint filler section 24 is formed as a gap between the end faces of adjacent PCa blocks 12, 12. Reinforcing bars 12r (Figure 4) protrude from the end faces of the PCa blocks 12, 12 in the joint filler section 24. As shown in Figure 5(a), formwork 27, 27 is installed on both sides of the joint filler section 24 in the wall thickness direction, and filler concrete 21 is poured into the joint filler section 24 so as to embed the reinforcing bars 12r. After that, the formwork 27 is removed, and the joint section 23 is completed as shown in Figure 5(b). Similarly, a joint section 23 is also formed between vertically adjacent PCa blocks 12, 12.
[0028] (Joint treatment process S207) Figure 6(a) is a horizontal cross-sectional view of the vicinity of the joint 23 during the joint treatment process S207. Figure 6(b) is a perspective view of the planned construction location 6 as seen from inside the tank during the joint treatment process S207. In the joint treatment process S207, a barrier layer 13 is formed in the joint 23. That is, at the completion of the precast member installation process S205 (Figure 5(b)), a barrier layer 13h is formed on the surface 12a of each PCa block 12, but since the barrier layer 13 is interrupted at the joint 23, in the joint treatment process S207, a barrier layer 13 is formed on the joint 23. Strictly speaking, what is formed here is only a part of the barrier layer 13 formed on the joint 23, so when distinguishing it, it is called the "barrier layer 13j".
[0029] Specifically, a barrier layer 13j is formed on the joint 23 by spraying a resin material R along the joint 23. At this time, the barrier layer 13j is formed by spraying the resin material R with a width that overlaps both adjacent barrier layers 13h, 13h on either side of the joint 23, so that the barrier layer 13 is connected in a continuous line on the inner surface of the concrete structure 11. Such spraying work is carried out, for example, using a climbing scaffold or gondola installed along the concrete structure 11. Alternatively, the barrier layer 13j may be formed by applying the resin material R to the joint 23 (for example, by brush application).
[0030] (Joint inspection process S209) In the joint inspection process S209, a quality confirmation inspection of the barrier layer 13j formed in the joint treatment process S207 is performed. Here, as in the barrier layer inspection process S203 mentioned above, a visual inspection of the barrier layer 13j and a pinhole test using a pinhole flaw detector are performed. Since the barrier layer 13h on the surface 12a of the PCa block 12 has already been inspected in the barrier layer inspection process S203, only the barrier layer 13j needs to be inspected here. This inspection work is carried out, for example, using a climbing scaffold or gondola installed along the concrete structure 11.
[0031] (Cold insulation layer construction process S211) In the insulation layer construction process S211, as shown in Figure 2, multiple insulation panels 16 are installed inside the barrier layer 13 to construct the insulation layer 15. Each insulation panel 16 is bolted to an insert nut 19a of the concrete structure 11 with the barrier layer 13 in between. A filler material 15t such as glass wool is packed between adjacent insulation panels 16.
[0032] (Metal inner tank construction process S213) In the metal inner tank construction process S213, as shown in Figure 2, multiple metal plates 18 are installed inside the insulation layer 15 to construct the metal inner tank 17. Each metal plate 18 is bolted to the insert nuts 19b of the concrete structure 11 with the insulation layer 15 and barrier layer 13 in between. The ends of adjacent metal plates 18 are overlapped in the thickness direction and welded together.
[0033] As shown in Figure 2, the insert nuts 19a and 19b used to bolt the insulation panel 16 and metal plate 18 are closed-end nuts, so the insulation layer 15 and the concrete structure 11 do not communicate through the nut holes. Furthermore, the barrier layer 13 is formed to straddle the boundary between the flanges of the insert nuts 19a and 19b and the concrete portion of the PCa block 12. This structure ensures that the liquid-tightness and airtightness of the barrier layer 13 are not impaired by the presence of the insert nuts 19a and 19b.
[0034] The effects and benefits of the wall construction method described above will now be explained.
[0035] In the wall construction method of this embodiment, a barrier layer 13h is formed on the surface of the PCa block 12 before it is installed at the planned construction location 6 in the precast member preparation step S201. Then, in the subsequent precast member installation step S205, this PCa block 12 is installed at the planned construction location 6 of the side wall 5. At this point, the barrier layer 13 at the planned construction location 6 is mostly formed except for the joint portion 23. Therefore, in the joint portion processing step S207, it is sufficient to form the barrier layer 13j over the joint portion 23. In other words, for work at height at the planned construction location 6 using climbing scaffolding or a gondola, etc., it is not necessary to process the surface portion 12a of the PCa block 12, and it is sufficient to form only the barrier layer 13j over the joint portion 23. For example, approximately 90% of the total area of the barrier layer 13 is already formed, and in the joint portion processing step S207, it is possible to form only the remaining approximately 10%. In this way, the amount of work at height is reduced, improving the safety of the construction of the side wall 5.
[0036] Furthermore, in the precast member preparation process S201, the barrier layer inspection process S203 is performed on the PCa block 12 before it is installed at the planned construction location 6. Therefore, by the time the PCa block 12 is installed at the planned construction location 6 of the side wall 5, the barrier layer 13h at the planned construction location 6 has already been inspected. Consequently, in the joint inspection process S209, only the barrier layer 13j of the joint 23 needs to be inspected during the work at height. Therefore, the work at height required for quality confirmation inspection of the barrier layer 13 is also reduced, further improving the safety of the construction of the side wall 5.
[0037] Furthermore, the formation of the barrier layer 13h and quality confirmation inspection in the precast member preparation process S201 can be performed at a factory where the PCa blocks 12 are manufactured, rather than at the planned construction site 6. Therefore, compared to performing the formation of the barrier layer 13h and quality confirmation inspection at the planned construction site 6 using climbing scaffolding or a gondola, more precise centralized quality control is possible, resulting in improved quality of the barrier layer 13h. In addition, in the precast member preparation process S201, the barrier layer 13h is formed on the surface 12a while the PCa blocks 12 are laid flat. Therefore, coating sagging of the resin material of the barrier layer 13h is suppressed, further improving the quality of the barrier layer 13h. Furthermore, in the barrier layer inspection process S203, quality confirmation inspection of the barrier layer 13h is performed while the PCa blocks 12 are laid flat, allowing for more precise inspection and further improving the quality of the barrier layer 13h.
[0038] Furthermore, in the construction of this type of side wall 5, the insulation layer 15 and the metal inner tank 17 are constructed sequentially inside after the completion of the barrier layer 13. Therefore, the process of forming the barrier layer 13 tends to be the critical path of the entire construction of the side wall 5. In contrast, according to the wall construction method of this embodiment, as described above, the work of forming the barrier layer 13 at the planned construction location 6 is reduced, shortening the work time and thus shortening the construction period of the side wall 5. Also, when the barrier layer 13 is formed at the planned construction location 6, the cost per unit may decrease due to concerns such as sagging of the resin material R. According to the wall construction method of this embodiment, the area of the barrier layer 13 to be formed at the planned construction location 6 is reduced, so the reduction in cost per unit as described above is suppressed, and the construction period can be further shortened.
[0039] Furthermore, in the side walls 5 of this type of tank 1, it is also conceivable to form the barrier layer 13 from a metal plate. In this case, welding strain generated by welding the metal plates together may cause the metal plates to warp, leaving irregularities on the surface of the barrier layer 13. If granular material such as perlite is injected and filled between the barrier layer 13 and the metal inner tank 17 to form the insulation layer 15, then irregularities on the surface of the barrier layer 13 do not pose a major problem. However, if the insulation layer 15 is formed from an insulation panel 16, the following problem arises. That is, due to the irregularities on the surface of the barrier layer 13, the insulation panel 16 tends to partially float above the surface of the barrier layer 13. In this case, when the insulation panel 16 is pressed against the barrier layer 13 by the liquid pressure of the liquid stored in the tank 1, bending behavior may occur in the insulation panel 16. Therefore, the insulation panel 16 needs to have sufficient strength to withstand bending deformation, and reinforcement of the insulation panel 16 may be necessary.
[0040] To address this problem, the barrier layer 13 of the side wall 5 in this embodiment is made of a sprayed or coated resin material, making it easy to form a smooth surface on the barrier layer 13. Therefore, the bending behavior of the insulation panel 16 caused by the surface irregularities of the barrier layer 13 as described above can be suppressed. Furthermore, since the insulation layer 15 of the tank 1 in this embodiment is made of insulation panels 16, higher insulation performance can be obtained compared to an insulation layer in which granular material is injected and filled as described above.
[0041] [Second Embodiment] Next, the wall construction method of the second embodiment will be described. The wall construction method of this embodiment differs from that of the first embodiment in part of the precast member installation process S205 and the joint processing process S207, but otherwise is the same as the first embodiment, so redundant explanations will be omitted.
[0042] Figure 7 is a horizontal cross-sectional view of the joint between PCa blocks 12, 12 that are adjacent in the circumferential direction at the planned construction position 6 during the precast member installation process S205. In the precast member installation process S205 and the joint processing process S207 of this embodiment, a normal formwork 27 is installed on the outside of the joint filler portion 24, and a concrete embedded formwork 31 is bolted to the inside of the joint filler portion 24. The surface 31a of the embedded formwork 31 facing the inside of the tank 1 is positioned almost flush with the inner surface 12a of the PCa blocks 12, 12. A barrier layer 13j is pre-formed on the inner surface 31a of the embedded formwork 31. The embedded formwork 31 with the barrier layer 13j on its surface is manufactured in advance at the factory. For example, a resin material R can be sprayed or applied to the surface 31a of the embedded formwork 31 to form the barrier layer 13j.
[0043] Subsequently, infill concrete 21 is poured into the joint filler section 24, the formwork 27 is removed, and the joint section 23 is completed. Since the embedded formwork 31 is left as part of the joint section 23, the inner surface of the concrete structure 11 has both a barrier layer 13h on the PCa block 12 and a barrier layer 13j on the joint section 23.
[0044] Subsequently, as shown in an enlarged view in Figure 8(a), steel plates 33 are bolted to the surface 31a of the buried formwork 31 and the surface 12a of the PCa block 12 so as to seal the circumferential gap between the buried formwork 31 and the PCa block 12. Then, the resin material R of the barrier layer 13 is sprayed or applied to seal the boundary between the steel plates 33 and the barrier layer 13h, and the boundary between the steel plates 33 and the barrier layer 13j, respectively, to form the barrier layer 13k. With this structure, the boundary between the barrier layer 13h and the barrier layer 13j is sealed by the steel plates 33 and the barrier layer 13k, completing an integrated barrier layer 13 that is liquid-tight and airtight. A portion of this integrated barrier layer 13 is made up of steel plates 33. In the buried formwork 31, the gaps that open up when the tank 1 is put into service tend to concentrate at the bolted portion of the buried formwork 31, but with this structure, the gaps are dispersed by the steel plates 33.
[0045] Instead of the structure shown in Figure 8(a), as shown in Figure 8(b), a fiber sheet 35 (for example, a glass cloth sheet) may be adhered to the surface 31a of the buried formwork 31 and the surface 12a of the PCa block 12 so as to seal the circumferential gap between the buried formwork 31 and the PCa block 12. Then, the resin material R of the barrier layer 13 is sprayed or applied onto the fiber sheet 35 to a width exceeding that of the fiber sheet 35 to form the barrier layer 13k. With this structure, the boundary between the barrier layer 13h and the barrier layer 13j is sealed by the fiber sheet 35 and the barrier layer 13k, completing an integrated barrier layer 13 with liquid-tightness and airtightness. Furthermore, with this structure, the fiber sheet 35 and the barrier layer 13k follow the opening of the tank 1 when it is in use, ensuring the liquid-tightness and airtightness of the barrier layer 13.
[0046] [Third Embodiment] Next, the wall construction method of the third embodiment will be described. The wall construction method of this embodiment differs from that of the first or second embodiment in part from the precast member installation process S205 and the joint processing process S207, but otherwise is the same as that of the first or second embodiment, so redundant explanations will be omitted.
[0047] In this embodiment, during the precast member installation process S205 and the joint treatment process S207, instead of the concrete embedded formwork 31 of the second embodiment, a steel embedded formwork 37 (metal embedded formwork) made of steel plate is installed inside the joint filler section 24 by bolts, as shown in Figure 9. Subsequently, filler concrete 21 is poured into the joint filler section 24, the formwork 27 is removed, and the joint section 23 is completed. After that, the resin material R of the barrier layer 13 is sprayed or applied so as to straddle each of the boundaries between the steel embedded formwork 37 and the barrier layers 13h, 13h, thereby forming the barrier layer 13k. Since the steel embedded formwork 37 has liquid-tightness and airtightness and functions as a barrier layer 13j in the joint section 23, it is not necessary to spray or apply the resin material R to the surface 37a of the steel embedded formwork 37. In other words, a part of this barrier layer 13 is composed of the steel embedded formwork 37. Furthermore, if the embedded steel formwork 37 is composed of multiple steel plates, the steel plates are not welded together, or if they are welded together, welding distortion is corrected beforehand. This ensures the flatness of the embedded steel formwork 37, and thus ensures the flatness of the barrier layer 13.
[0048] The present invention can be implemented in various forms, including the embodiments described above, by making various changes and improvements based on the knowledge of those skilled in the art. Furthermore, it is possible to construct modified versions by utilizing the technical matters described in the embodiments described above. The configurations of each embodiment may also be used in appropriate combinations.
[0049] For example, in each embodiment, the concrete structure 11 is composed of a plurality of PCa blocks 12 (precast members) arranged in the direction of the wall, but is not limited to this. For example, as shown in Figure 10(a), the concrete structure 11 may be composed of a concrete embedded formwork 41 (precast member) that forms a part of the inside of the concrete structure 11, and a concrete section 43 that is cast in place on the outside of the embedded formwork 41. In this case, in the precast member preparation step S201, as shown in Figure 10(b), for example, the embedded formwork 41 is manufactured in a factory, and a barrier layer 13h is formed on the surface 41a of the embedded formwork 41 that corresponds to the inside of the tank 1 while the embedded formwork 41 is laid flat.
[0050] Then, in the precast member installation process S205, as shown in Figure 10(a), the embedded formwork 41 with a barrier layer 13h formed on its surface 41a is installed at the planned construction location 6. Then, the concrete section 43 is poured on the outside of the embedded formwork 41 to construct the concrete structure 11. Subsequently, in the joint treatment process S207, a barrier layer 13j is formed in the joints between adjacent embedded formwork 41, similar to the first embodiment shown in Figure 6(b), to seal the gaps between the barrier layers 13h and 13h, thereby forming an integrated barrier layer 13.
[0051] Furthermore, in each embodiment, the process of forming a barrier layer 13h on the surface 12a of the PCa block 12 is performed at the factory, but the formation of such a barrier layer 13h may be performed on-site before the precast member installation process S205. Also, in each embodiment, the insulation layer 15 is composed of a plurality of insulation panels 16, but the insulation layer 15 may be formed by injecting and filling granular material such as perlite between the barrier layer 13 and the metal inner tank 17. Also, in each embodiment, the tank 1 is an above-ground tank, but the present invention may also be applied to underground tanks. Also, in each embodiment, the tank 1 is a low-temperature tank, but the process of forming the predetermined layer in the joints between precast members after a precast member with a predetermined layer already formed on its surface is installed at the planned construction location of the tank wall may be applied not only to low-temperature tanks but also to water tanks and the like. [Explanation of Symbols]
[0052] 1...Above-ground tank, 5...Side wall (wall body), 6...Planned construction location, 11...Concrete structure, 12...PCa block (precast member), 12a...Surface, 13,13h,13j,13k...Barrier layer, 15...Insulation layer, 17...Metal inner tank, 21...Infill concrete, 23...Joint section, 24...Joint fill section, 31...Buried formwork, 31a...Surface, 37...Steel buried formwork (metal buried formwork), 41...Buried formwork (precast member), 41a...Surface, S201...Precast member preparation process, S205...Precast member installation process, S207...Joint section treatment process, S203...Barrier layer inspection process.
Claims
1. A method for constructing a tank wall comprising: a concrete structure formed including precast members arranged in the direction of the wall surface; a barrier layer provided inside the concrete structure and having liquid-tight and airtight properties; a cooling layer provided inside the barrier layer; and an inner tank provided inside the cooling layer, wherein the tank wall is constructed, A precast member preparation step involves preparing the precast member on which the barrier layer is formed on its surface, A precast member installation step involves installing the precast member, which has the barrier layer formed on its surface, at the planned construction location of the wall. The process includes a joint treatment step of forming the barrier layer in the joint between adjacent precast members at the planned construction location, In the aforementioned joint treatment process, A method for constructing a wall, wherein, as a separate component from the barrier layer formed on the surface of the precast member, a buried formwork for pouring filler concrete into the joints between the precast members is installed in the joints, the barrier layer is formed in advance on the surface of the buried formwork, and after the filler concrete is poured, the barrier layer is formed to close the boundary between the buried formwork and the barrier layer on the precast member.
2. A method for constructing a tank wall comprising: a concrete structure formed including precast members arranged in the direction of the wall surface; a barrier layer provided inside the concrete structure and having liquid-tight and airtight properties; a cooling layer provided inside the barrier layer; and an inner tank provided inside the cooling layer, wherein the tank wall is constructed, A precast member preparation step involves preparing the precast member on which the barrier layer is formed on its surface, A precast member installation step involves installing the precast member, which has the barrier layer formed on its surface, at the planned construction location of the wall. The process includes a joint treatment step of forming the barrier layer in the joint between adjacent precast members at the planned construction location, In the aforementioned joint treatment process, A method for constructing a wall, wherein, as a separate component from the barrier layer formed on the surface of the precast member, a metal embedded formwork for pouring filler concrete into the joints between the precast members is installed in the joint filler, the metal embedded formwork constitutes the barrier layer in the joint, and after the filler concrete is poured, the barrier layer is formed so as to straddle the boundary between the metal embedded formwork and the barrier layer on the precast member.
3. A method for constructing a tank wall comprising: a concrete structure formed including precast members arranged in the direction of the wall surface; a barrier layer provided inside the concrete structure and having liquid-tight and airtight properties; a cooling layer provided inside the barrier layer; and an inner tank provided inside the cooling layer, wherein the tank wall is constructed, A precast member preparation step involves preparing the precast member on which the barrier layer is formed on its surface, A precast member installation step involves installing the precast member, which has the barrier layer formed on its surface, at the planned construction location of the wall. The process includes a joint treatment step of forming the barrier layer in the joint between adjacent precast members at the planned construction location, In the aforementioned joint treatment process, A method for constructing a wall, wherein a formwork for pouring filler concrete into the joint between precast members is installed in the joint, and after the filler concrete is poured, the formwork is removed to form the joint, and then a resin material is applied or sprayed on both of the precast members with a width that overlaps the barrier layer, thereby forming the barrier layer on the joint.
4. In the precast member preparation process, A method for constructing a wall according to any one of claims 1 to 3, wherein the barrier layer is formed on the surface of the precast member by coating or spraying while the precast member is laid flat.
5. A method for constructing a wall according to any one of claims 1 to 3, further comprising a barrier layer inspection step of inspecting the barrier layer on the surface of the precast member before the precast member installation step.