JPH0321710B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for assembling a circular water tank used as a sedimentation basin, water storage tank, etc. in a sewage treatment plant.

[Prior Art] Conventionally, this type of circular aquarium has generally been constructed using so-called cast-in-place concrete. For this reason, on-site formwork construction and reinforcing steel construction are essential, making the work more complicated. Therefore, there are problems in that it is difficult to shorten the construction period and reduce costs, and there are certain limits to quality control.

Therefore, recently, it has been considered that a cylindrical peripheral wall is constructed by arranging a plurality of retaining wall blocks, which are secondary concrete products, in the circumferential direction. That is, this circular aquarium is a circular aquarium comprising a cylindrical peripheral wall formed by arranging a plurality of retaining wall blocks in the circumferential direction, and a bottom plate continuous to the base of the peripheral wall. At least one of the retaining wall blocks is provided with a connecting box, and an insertion hole communicating with the connecting box is provided inside each of the retaining wall blocks, and a prestressing steel material is inserted into the insertion hole at both ends thereof. A screw portion is positioned and inserted into the connecting box, and nuts are screwed into the screw portions at both ends of the PC steel material to tightly connect the retaining wall blocks.

[Problems to be Solved by the Invention] However, in the conventional method, the connecting box is buried in concrete at the same time as the retaining wall block is manufactured, so the outer surface of the connecting box is buried in concrete. It is closely tied to the organization. Therefore, problems are likely to occur when the nut is tightened to apply tension to the PC steel material. In other words, when tension is applied to the PC steel material,
Tensile force also acts on the connection box that connects these prestressed steel materials. Therefore, even when the connecting box is made of metal, a small amount of elongation occurs depending on the tensile force. Then, due to the elongation, a force is applied that tries to expand the concrete structure of the portion of the retaining wall block that surrounds the connection box, resulting in a partial lack of strength in the retaining wall block. To be more specific, as shown in Fig. 15, a compressive force based on the tension of the prestressing steel material c acts on the part of the concrete structure that does not correspond to the connection box b of the retaining wall block a.
A tensile force may act on the concrete structure portion corresponding to the connecting box b due to the elongation of the connecting box b. Therefore, cracks and the like are likely to occur in this portion, causing problems in durability.

The present invention aims to solve the above problems all at once.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for assembling a circular aquarium as described above in which a plurality of retaining wall blocks are tightly connected using prestressed steel. The box is housed in a recess provided in the retaining wall block, and when the box is housed, an edge layer is provided between both end faces in the circumferential direction of the connecting box and the corresponding inner wall surface of the recess. ,
It is characterized in that the circumferential elongation of the connecting box caused when tension is applied to the prestressing steel material is absorbed by the edge cutting layer.

[Function] First of all, for a circular aquarium like this, the surrounding wall can be constructed by combining multiple retaining wall blocks on site, so there is no need for large-scale formwork or reinforcing work to construct the surrounding wall. becomes unnecessary. Furthermore, since the retaining wall blocks are tightly connected to each other by the prestressing steel, there is no possibility that the retaining wall blocks will shift due to uneven earth pressure or the like. Tightening using the prestressed steel material can be carried out by positioning both ends of the prestressed steel material inserted into the insertion holes of each block within the connection box, and fixing fasteners such as nuts to each end. Therefore, it is easy to connect retaining wall blocks together.

Furthermore, when assembling such a circular aquarium, a cutting layer is provided between both circumferential end surfaces of the connecting box and the inner wall surface of the recess that accommodates the connecting box, so that tension is not applied to the prestressing steel material. Even if the connection box expands in the circumferential direction due to the application, the expansion will be absorbed by the edge cutting layer. Therefore, it is possible to suppress or prevent the concentrated tensile force caused by the tension of the prestressing steel material from acting on the concrete structure portion of the retaining wall block corresponding to the connecting box.

[Example] Hereinafter, an example in which the present invention is applied to a circular water tank used as a first sedimentation tank or a final sedimentation tank in a sewage treatment plant will be described with reference to FIGS. 1 to 11.

FIG. 1 is a plan sectional view showing an assembled circular aquarium, and FIG. 2 is a front sectional view thereof. As shown in these drawings, this circular aquarium includes a cylindrical peripheral wall 2 formed by arranging a plurality of retaining wall blocks 1 ₁ to 1 ₉ in the circumferential direction, and a base 2 of this peripheral wall 2.
A and a bottom plate 3 are provided continuously.

As shown in FIG. 3, each of the retaining wall blocks 1 ₁ to 1 ₉ is a curved plate-shaped concrete block with a fan-shaped plane cross section, and a flange 4 corresponding to the thickness of the bottom plate 3 is attached to the base 2 a of the retaining wall blocks 1 1 to 1 9 . have. In addition,
The center of curvature of the inner circumferential surface 1a and outer circumferential surface 1b of each retaining wall block ₁₁ to ₁₉ is on the center line n of the circular tank, and when the left and right joint end surfaces 5 and 6 are extended, the center line It is set so that they intersect on n. Therefore, these retaining wall blocks 1 ₁ to 1 ₉
By joining these, a perfectly circular peripheral wall 2 is formed. As shown in FIGS. 4 and 5, two parallel seal grooves 7 are provided on one joint end surface 5 of each retaining wall block 1 ₁ to 1 ₉ from the upper end to the lower end. Each of these seal grooves 7 is fitted with a seal material 8 made of water-expandable rubber. In addition, each retaining wall block 1 ₁ to 1 ₉ has a third
As shown in FIGS. 10 and 11, four connecting boxes 9 made of metal in the form of a housing are provided with openings on the outer circumferential surface 1b, and a sheath is buried inside the block 1. Therefore, a curved insertion hole 1 is provided which communicates with each connection box 9 and opens the box 9 to each of the joint end surfaces 5 and 6.
1 are provided, and each of these through holes 11 can be matched with each of the through holes 11 of the adjacent retaining wall block 1, respectively. A prestressed steel rod 12, which is a prestressed steel material, is inserted into each of these insertion holes 11. Each PC steel bar 12 has threaded portions 12 at both ends.
A, 12b is a steel bar, and a threaded portion 12a formed at one end is connected to a specific retaining wall block 1.
The retaining wall blocks 1 adjacent to the specific retaining wall blocks ₁ 1 to 1 ₉ are made to protrude into the connection boxes 9 of ₁ to 1 ₉ and have screw portions 12 b formed at the other end.
It is located in the connection boxes 9 numbered ₁ to ₁₉ .
Then, in the connection box 9, a nut 14 serving as a fastener is screwed onto each of the threaded portions 12a and 12b via the anchor plate 13, and the nut 14 is tightened to apply tension to the PC steel bar 12. Possibly adjacent retaining wall block 1 ₁ and 1
₂ , 1 ₂ and 1 ₃ ...1 ₈ and 1 ₉ , 1 ₉ and 1 ₁ are tightly connected.

By the way, the detailed method of assembling such a circular water tank is as follows. First, recesses 15 are provided on the outer surface of each of the retaining wall blocks 1 ₁ to 1 ₉ and communicate with the respective insertion holes 11 , and the connection boxes 9 are accommodated in each of these recesses 15 . That is, the connecting box 9 is in the form of a housing having through holes 16 in both end walls 9a and 9b communicating with the insertion hole 11, and is loosely fitted into the recess 15 with the opening facing outward. In this case, a border layer 17 is provided between both end surfaces 9a ₁ and 9b ₁ in the circumferential direction of the connection box 9 and the inner wall surfaces 15a and 15b of the recessed portion 15.
Form it. As shown in FIG. 10, the edge cutting layer 17 of this embodiment is constituted by an easily deformable solid layer, for example, a rubber layer. Then, such retaining wall blocks 1 ₁ to 1 ₉ are sequentially connected in the circumferential direction to construct the peripheral wall 2. To be more specific, the 6th
As shown in the drawings and FIG. 7, first, the second retaining wall block ₁₂ is arranged next to the first retaining wall block ₁₁ while being guided by the partially arcuate guide member 18. Then, a PC steel rod 22 is inserted into each insertion hole 11, and the screw portion 12a on one end side of each PC steel rod 12 is made to protrude into the connection box 9 of the first retaining wall block ₁₁ , and the other Connect the screw portion 12b on the end side to the second retaining wall block 1 ₂
It protrudes into the connection box 9. Then, a nut 14 is fixed to a threaded portion 12a formed at one end via an anchor plate 13, and a nut 14 is temporarily fixed to a threaded portion 12b formed at the other end via an anchor plate 13. Next, as shown in FIG. 8, a special center hole type hydraulic jack manufactured according to the dimensions of the connecting box 9 is installed in each connecting box 9 of the _second retaining wall block 12. 19, and while applying tension to each PC steel bar 12 all at once with these hydraulic jacks 19, fully tighten the nut 14 temporarily fixed to the other end threaded part 12b of each PC steel bar 12 to fix it. , and then each hydraulic jack 19
Take it out of the connection box 9. The hydraulic jack 19 is connected to the center hole 2 as shown in FIG.
A piston 23 is integrally provided on the outer periphery of an operating shaft 22 having a cylinder 24, and this piston 23 is slidably fitted into a cylinder 24, and the operating shaft 2
Both ends of the cylinder 24 are exposed outside the cylinder 24. Pressure oil can be introduced into one end surface of the piston 23 through an oil lead-in/out port 25, and the other end surface of the piston 23 is pressed by a return spring 26. The center hole 21 of the operating shaft 22 has a core member 2 having a screw hole 27 at the tip and a flange 28 at the base end.
9 is rotatably inserted, and the threaded portion 12b of the PC steel rod 12 can be screwed into the screw hole 27 of this core material 29. Therefore, when using this hydraulic jack 19, a frame-shaped spacer 32 that forms a space 31 for tightening the nut is interposed between the anchor plate 13 and the cylinder 24, and then the PC steel rod 12 is The threaded portion 12b and the core material 29 are screwed together. After that, pressure oil is introduced into the oil lead-in/out port 25, and the piston 23 and the operating shaft 2
2 and the core material 29, and the PC steel rod 12
Towing. In this state, a wrench (not shown) is inserted into the space 31 formed by the spacer 32 from the outside.
, and fully tighten the nut 14. Thereafter, the pressure in the oil lead-in/out port 25 is released and the piston 23 and operating shaft 22 are moved forward by the biasing force of the spring 26, thereby freeing the core material 29 and screwing it off from the PC steel rod 12. and,
The hydraulic jack 19 and spacer 32 are taken out of the connection box 9.

The first retaining wall block 1 ₁ and the second retaining wall block 1 ₂ are tightly connected by the above procedure, but the second retaining wall block 1 ₂ and the third retaining wall block
1st retaining wall block 1 ₃ , 3rd retaining wall block 1 ₃ , 4th retaining wall block 1 ₄ ... 8th retaining wall block 1 ₈ and 9th (last) retaining wall block 1 ₉ are also connected by the same procedure.
Furthermore, the connection between the last retaining wall block ₁₉ and the first retaining wall block ₁₁ is performed in the same manner.
Note that since the guide member 18 is made in a shape having a curvature corresponding to the peripheral wall 2, the retaining wall block 1 ₁ is slid along the guide member 18 while sequentially sliding the guide member 18 in the circumferential direction. ~
By sequentially arranging and connecting the retaining wall blocks _1-8 , the retaining wall blocks _1-9 and the first retaining wall block _1-1 will finally match exactly.

In this way, all retaining wall blocks 1 ₁ ~
1 ₉ are tightly connected by the PC steel rod 12,
The tensile force of these PC steel bars 12 also applies a tensile force in the circumferential direction to each connecting box 9, causing elongation in the circumferential direction. It is becoming absorbed. After completing all the tightening using the PC steel rod 12, the insertion hole 1 is inserted from the injection hole 13a provided in the anchor plate 13.
Grout (not shown) is injected into the connecting box 9, and mortar (not shown) is filled into the connecting box 9.

On the other hand, the bottom slab 3 is made by pouring concrete between the tips of the flanges 4 of the retaining wall block 1, and has a central part for mounting a stirring device (not shown), etc. It has a recess 3a.

In addition, 33 is foundation stone, 34 is foundation concrete, 35 is mortar, and 36 is reinforcement.

With this kind of configuration, the surrounding wall 2 can be created by combining multiple retaining wall blocks 1 on-site, eliminating the need for large-scale formwork or reinforcing work for constructing the surrounding wall. This greatly reduces the complexity of on-site work. In addition, since the retaining wall block 1 can be manufactured by mass production methods during construction, etc., it is possible to perform sufficient quality control, and the circular water tank has high dimensional accuracy and is easy to reduce costs. can be provided. Furthermore, since the retaining wall blocks 1 are tightly connected by the PC steel rods 12, there is no possibility of positional displacement due to uneven earth pressure that is applied during the above-mentioned backfilling work. The tightening by the PC steel rod 12 is
After positioning the screw portions 12a and 12b at both ends of the PC steel rod 12 inserted into the insertion hole 11 of each retaining wall block 1 in the connection box 9,
Since this can be done by screwing the nuts 14 onto the retaining wall blocks 12b, it is easy to connect the retaining wall blocks 1 to each other, and the work does not become complicated.

Moreover, both end surfaces 9 in the circumferential direction of the connection box 9
A cutting layer 17 is provided between _{a 1} and 9b ₁ and the corresponding inner wall surfaces 15a and 15b of the concave portion 15, and the nut 14 is tightened to remove the PC steel bar 12.
Since the circumferential elongation of the connection boxes 9 caused when tension is applied to the connection boxes 9 is absorbed by the edge cutting layer 17, the connection There is no inconvenience such as the concrete structures of the retaining wall blocks ₁₁ to ₁₉ being strongly pressed in the left and right direction by the end faces of the storage boxes. Therefore, it is possible to effectively prevent the inconvenience that a large tensile force is applied to the portion of the retaining wall block that corresponds to the connection box.
Therefore, it is possible to apply compressive force based on the tension of the PC steel rods 12 to all areas and all joints of all retaining wall blocks, and there is no water leakage.
Moreover, a highly durable circular aquarium can be constructed.

By the way, a turnbuckle-shaped connector having female threads at both ends is known as a connecting member for connecting PC steel bars to each other without applying tensile force to the concrete structure of the retaining wall block. Since such connectors require alignment of the PC steel bars to be connected, curved PC
It is impossible to connect steel rods together. On the other hand, if the connecting box 9 is used as a connecting member as in the present invention, alignment is not required.
PC steel bars 12 can be connected to each other. Therefore, it is possible to reliably and easily connect a plurality of concrete blocks forming a cylindrical body, that is, the retaining wall blocks 1.

In addition, in the above embodiment, the case where the edge cutting layer is an easily deformable solid layer made of rubber, asphalt-based inclusions, etc. has been described, but the present invention is not necessarily limited to such a layer, and for example, ,
It may be a layer formed of a flowable liquid such as grease, or an air layer where air simply exists. Alternatively, the solid layer, liquid layer and air layer may be appropriately combined to form the edge layer.

Further, in the above embodiment, the case where the present invention is applied to a circular aquarium having a single peripheral wall has been described, but the present invention is not limited to such a tank. Similarly, the present invention can be applied to a circular aquarium having a plurality of peripheral walls. That is, what is shown in FIGS. 12 and 13 is a circular water tank used as a treatment tank in a small-scale sewage treatment facility or the like. Therefore, this circular aquarium has a cylindrical inner wall A and an inner wall A.
It has a double cylindrical structure comprising a cylindrical outer wall B surrounding the inner wall, and the inner space of the inner wall is used as a settling basin C, and the inner wall B is formed between the inner wall A and the outer wall B. The annular space is used as an aeration tank D.

The inner wall A is formed by arranging a plurality (m) of retaining wall blocks 1A ₁ to 1A _n , which are connecting blocks, in the circumferential direction. They are connected by steel rods. The outer wall B is formed by arranging a plurality (n) of retaining wall blocks 1B ₁ to 1B _o , which are connecting blocks, in the circumferential direction, and is made of PC steel in the same manner as the peripheral wall 2 of the previous embodiment. connected by rods.

Furthermore, it goes without saying that the number and shape of the retaining wall blocks to be combined are not limited to those shown in the figures, and can be modified in various ways without departing from the spirit of the present invention. For example, as shown in FIG. 14, the same applies to a retaining wall block 101 that integrally has a flange 104 projecting toward the inner circumference and a flange 105 projecting toward the outer circumference. is possible.

Furthermore, PC steel materials are not limited to steel bars, for example,
It may also be a strand or the like. However, if the PC steel material is a strand, it is difficult to form a threaded portion at the end thereof, so a fastener other than a nut may be used to fix the strand. Fixing devices other than nuts include, for example, a ring-shaped cone that loosely fits around the outer periphery of the end of the prestressing steel material, and a ring-shaped cone that is driven between the inner wall of this cone and the prestressing steel material to hold the prestressed steel material in place. A grip having a wedge-shaped cross section is conceivable.

Further, the connecting box may be opened and fitted into the inner circumferential surface of the retaining wall block.

[Effects of the Invention] As detailed above, the circular water tank obtained by the present invention has its peripheral wall made up of a plurality of retaining wall blocks, so it is possible to eliminate the complexity of on-site work and shorten the construction period. It is possible to shorten the time and reduce costs. In addition, each retaining wall block can be
Since they are connected by steel, there is no problem of displacement of the retaining wall blocks during backfilling or the like. Since the connection using the prestressed steel material is completed by fixing fasteners to each end of the prestressed steel material located within the connection box, assembly is also extremely easy. Moreover, when assembling such a circular aquarium, the connecting box is housed in the recessed part of the retaining wall block, and when the connecting box is housed, both circumferential end faces of the connecting box and the corresponding recessed part are An edge cutting layer is provided between the inner wall surface and the edge cutting layer absorbs the elongation in the circumferential direction of the connecting box caused when tension is applied to the prestressing steel material. , it is possible to eliminate the inconvenience of tensile force acting on the concrete structure of the retaining wall block corresponding to the connecting box. Therefore, the excellent effect of preventing the occurrence of cracks and the like and effectively improving the durability of the peripheral wall can be obtained.

[Brief explanation of the drawing]

1 to 11 show an embodiment of the present invention, in which FIG. 1 is a plan sectional view, FIG. 2 is a front sectional view, and FIG. 3 is a front sectional view.
The figure is a perspective view of the retaining wall block, Figure 4 is a sectional view taken along line A-A in Figure 1, and Figure 5 is B in Figure 4.
- An enlarged sectional view along line B, Figure 6 is a perspective view to explain the method of joining retaining wall blocks, Figure 7 is a plan view of the same, and Figure 8 is to explain the method of applying tension to the prestressing steel material. Front view of the connecting box part for
Figure 9 is an enlarged partially cutaway front view showing the hydraulic jack used to apply tension to the prestressing steel.
FIG. 10 is a plan sectional view showing the connection box portion immediately after connection, and FIG. 11 is a front view thereof. 12 and 13 show other embodiments, with FIG. 12 being a plan view and FIG. 13 being a front sectional view. FIG. 14 is a perspective view showing still another embodiment of the present invention.
FIG. 15 is an explanatory diagram showing a conventional example. 1 ₁ to 1 ₉ , 1A ₁ to 1A _n , 1B ₁ to 1B _o ... Retaining wall block, 1a ... Inner peripheral surface, 1b ... Outer peripheral surface, 2
...Peripheral wall, 2a...Base part, 3...Bottom plate, 3a...
... recess, 4 ... flange, 5, 6 ... joint end surface,
7... Seal groove, 8... Seal material, 9... Connection box, 9a, 9b... End wall, 9a ₁ , 9b ₁ ...
End face, 11... Insertion hole, 12... PC steel material (PC steel bar), 12a, 12b... Thread part, 13... Anchor plate, 13a... Inlet, 14... Fastening tool (nut), 15 ...Concave portion, 15a, 15b
... Inner wall surface, 16 ... Through hole, 17 ... Marginal layer, 1
8... Guide member, 19... Hydraulic jack, 21
... Center hole, 22 ... Operating axis, 23 ...
Piston, 24... Cylinder, 25... Oil lead-in/out port, 26... Return spring, 27... Screw hole, 28... Flange, 29... Core material, 31...
...space, 32...spacer, 33...basic chestnut stone,
34... Foundation concrete, 35... Mortar laying, 36... Reinforcement, 101... Retaining wall block,
104, 105...Flange.

Claims (1)

[Scope of Claims] 1. At least one of the plurality of retaining wall blocks arranged in the circumferential direction and constituting the cylindrical peripheral wall is provided with a recessed portion to house the connection box therein, and each of the aforementioned An insertion hole is provided inside the retaining wall block to be inserted into the connection box, and a prestressed steel material is inserted into this insertion hole with both ends positioned within the connection box, and both ends of the prestressed steel material are inserted. A method of assembling a circular aquarium in which the retaining wall blocks are tightly connected to each other by fixing a fastening device to the retaining wall blocks, the method comprising: fixing the retaining wall blocks to each other and tightly connecting the retaining wall blocks; An edge cutting layer is provided between the end face and the corresponding inner wall surface of the concave portion, and the circumferential elongation of the connection box caused when tension is applied to the prestressing steel material is controlled by the edge cutting layer. A method for assembling a circular aquarium, characterized by absorbing water into layers. 2. The method for assembling a circular aquarium according to claim 1, wherein the edge cutting layer is an air layer. 3. The method of assembling a circular aquarium according to claim 1, wherein the edge layer is a layer of flowable liquid. 4. The method of assembling a circular aquarium according to claim 1, wherein the edge cutting layer is a solid layer that is easily deformable.