JPH0316459B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circular underground water tank that can be suitably used as a sedimentation tank, water storage tank, etc. in a sewage treatment plant.

[Prior Art] Conventionally, this type of circular underground water tank 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, in recent years, consideration has been given to constructing peripheral walls using secondary concrete products, which require relatively time-consuming work such as form work. That is, this circular aquarium is constructed by arranging a plurality of retaining wall blocks that have been manufactured in advance through construction work or the like in the circumferential direction to form a peripheral wall, and by driving a bottom slab into the base of the peripheral wall.

[Problems to be Solved by the Invention] By the way, earth pressure acts on the peripheral wall of such a water tank from outside, and water pressure acts on it from inside. Therefore, the force acting on each of the retaining wall blocks differs depending on the amount of water stored. However, in order to completely rigidly connect the retaining wall blocks to each other, extremely high strength is required at the joints. Therefore, if the surrounding wall is simply made up of blocks lined up horizontally, the blocks are likely to become misaligned due to water leakage or earth pressure, and to prevent this, large-scale reinforcement work is required at each joint. , the purpose of constructing the peripheral wall is lost due to the secondary concrete product.

The present invention aims to reliably solve these problems with a simple configuration.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a system in which a water tank is formed by alternately arranging first retaining wall blocks and second retaining wall blocks in the circumferential direction. A perfectly circular peripheral wall is erected on the foundation, the surrounding wall is backfilled with soil to form a circular underground type, and the first retaining wall block is integrally connected to the foundation. At the same time, the adjacent second retaining wall block is
a locking surface portion for preventing outward movement of the retaining wall block, and a portion corresponding to the locking surface portion between the joint end surface of the first retaining wall block and the joint end surface of the second retaining wall block; It is characterized by interposing a sealing material in the.

[Function] If the underground water tank has such a configuration, the amount of water stored is small, and if external forces mainly due to earth pressure act on the surrounding wall, each retaining wall block will have a A compressive force is applied in the circumferential direction, and the perfect circular shape of the peripheral wall is firmly maintained. On the other hand, when a force from the inside to the outside is applied to each retaining wall block due to the water pressure inside the water tank, the retaining wall blocks are integrated into the foundation more than the first retaining wall block, which is integrally connected to the foundation. Since the second retaining wall block that is not attached tends to have a larger amount of outward deviation, the second retaining wall block is pressed against the locking surface of the first retaining wall block. The sealing material interposed in that area is effectively consolidated.
Therefore, the sealing properties at the joint end surfaces between the respective retaining wall blocks are improved.

[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 8.

FIG. 1 is a partially cutaway schematic plan view showing a circular underground water tank according to the present invention (the shape of the joint end surface is simplified), and FIG. 2 is a - in FIG. 1. FIG. As shown in these drawings, this water tank has a cylindrical peripheral wall 3 formed by alternately arranging a plurality of first retaining wall blocks 1 and second retaining wall blocks 2 in the circumferential direction. and a bottom plate 4 provided continuously to the base portion 3a of the peripheral wall 3. As shown in FIGS. 3 to 5, each retaining wall block 1, 2 is a curved plate-shaped concrete block, and a flange 5 corresponding to the thickness of the bottom plate 4 is provided at the base 3a.
6. The centers of curvature of the inner peripheral surfaces 1a, 2a and the outer peripheral surfaces 1b, 2b of each retaining wall block 1, 2 are on the center line n of the water tank. Therefore, by joining a required number of these retaining wall blocks 1 and 2, a perfectly circular peripheral wall 2 can be formed. The joint end surfaces 7 existing at both ends of the first retaining wall block 1 include locking surfaces 8 and 9 and a slope portion 10. The locking surfaces 8 and 9 are
These are parallel planes whose normal lines face approximately in the direction n of the center of the water tank, and the slope portion 10 is formed between these two locking surfaces 8 and 9. The slope portion 10 is a slope whose normal line faces in an oblique direction. On the other hand, the joint end surfaces 11 existing at both ends of the second retaining wall block 2 are
Outward surface portions 12, 1 that come into contact with the locking surface portions 8, 9
3, and a slope portion 14 that abuts the slope portion 9. The joint end face 7 of the first retaining wall block 1 and the joint end face 1 of the second retaining wall block 2
A sealing material 17 is interposed at a portion corresponding to the locking surface portions 8 and 9 between the locking surfaces 1 and 1. Specifically, a seal groove 1 is formed in one locking surface portion 8 and one outward facing surface portion 12 from the upper end to the lower end of the retaining wall blocks 1 and 2.
5 and 16 are formed, and a water-expandable rubber sealing material 17 is attached to the seal grooves 15 and 16. The seal grooves 15 and 16 are stepped recesses formed by forming narrow grooves 15b and 16b at the center of the bottom of wide grooves 15a and 16a, and a sealing material 17 having a rectangular cross section is fitted into the narrow grooves 15b and 16b. There is.

In addition, in each of the second retaining wall blocks 2, four connection boxes 18 made of housing-shaped metal are buried with openings on the outer circumferential surface 2b, and inside each of the retaining wall blocks 1 and 2, Each connection box 18
A curved insertion hole 19 is provided which communicates with the.
In each of these insertion holes 19, a PC steel rod 2 is inserted.
0 is inserted. Each PC steel bar 20 is a steel bar having threaded parts 20a and 20b at both ends, and one threaded part 20a is attached to a specific retaining wall block 2.
It protrudes into the connection box 18, and
The other threaded portion 20b is located within the connection box 18 of the other retaining wall block 2. Then, in the connection box 18, each of the screw portions 20
A and 20b are screwed together with nuts 22 via anchor plates 21, and by tightening the nuts 22 and applying tension to the PC steel rods 20, adjacent retaining wall blocks 1 and 2 are connected. There is.
Incidentally, the insertion hole 19 and the connection box 18 are filled with mortar (not shown) after tightening with the PC steel rod 20 is completed. In this way, each retaining wall block 1,
The reason why the two retaining wall blocks 1 and 2 are connected is to prevent the retaining wall blocks 1 and 2 from being misaligned due to uneven earth pressure generated when backfilling the surrounding wall 3 with soil.

On the other hand, the bottom slab 4 is made by pouring concrete between the tips of the flanges 5 and 6 of the retaining wall blocks 1 and 2, and a stirring device (not shown) is installed in the center of the bottom slab 4. Recess 4a for mounting
have.

Note that 23 is a foundation consisting of foundation stone 24, foundation concrete 25, and mortar 26, and the peripheral wall 3 is erected on this foundation 23. Each first retaining wall block 1 is integrally connected to this foundation 23 via an anchor rod 27, respectively. Further, 28 is an insert line.

With this kind of configuration, by combining multiple retaining wall blocks 1 and 2 on site,
Since the surrounding wall 3 can be made, there is no need for large-scale form work or reinforcing work for constructing the surrounding wall.
The complexity of on-site work can be significantly reduced. Further, since the retaining wall blocks 1 and 2 can be manufactured in a factory or the like using a mass production method, it is possible to perform sufficient quality control.
It is possible to provide a circular aquarium that has high dimensional accuracy and is easy to reduce costs. Moreover, since the retaining wall blocks 1 and 2 are arranged in the circumferential direction to form a perfectly circular peripheral wall 3, the amount of water stored is small.
When an external force mainly due to earth pressure acts on the circumferential wall 3, compressive force in the circumferential direction acts on each retaining wall block 1, 2, and the perfect circular shape of the circular wall 3 is maintained. . On the other hand, when a force from the inside to the outside is applied to each retaining wall block 1, 2 due to the water pressure inside the water tank, the first retaining wall block 1, which is integrally connected to the foundation 23, Since the second retaining wall block 2 that is not integrated with the foundation 23 tends to have a larger amount of outward deviation, the second retaining wall block 2 is larger than the first retaining wall block 1. It will be pressed against the locking surfaces 8 and 9, and the sealing material 17 interposed at that portion will be effectively compressed. Therefore, the joint end surfaces 7, 1 between each retaining wall block 1, 2
The sealing performance in one part becomes good.

The number of retaining wall blocks to be combined is, of course, not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

Further, the shape of the retaining wall block is not limited to that of the above embodiment, and for example, the shape of the retaining wall block may not have a flange at all at the base, or may have a flange that protrudes toward the inner circumference.
They may each have integral flanges that protrude toward the outer periphery.

Moreover, the object of application is of course not limited to the initial or final sedimentation tank of a sewage treatment plant, but may also be applied to, for example, a water storage tank such as a fire prevention water tank. When used as a water storage tank, a lid is provided on the upper end of the tank.

[Effects of the Invention] As described in detail above, the circular underground water tank according to the present invention has its surrounding 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. Furthermore, by effectively utilizing earth pressure and water pressure, it is possible to improve the shape retention of the surrounding wall and the sealing performance between each retaining wall block, so the reinforcement of the joints between each retaining wall block is kept to a minimum. It is possible to provide an underground water tank that is economical and has high water-stop performance.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which FIG. 1 is a partially cutaway schematic plan view, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIG. 3 is a first retaining wall block. Fig. 4 is an external view of the joint end showing the second retaining wall block, Fig. 5 is a partially enlarged plan view showing the surrounding wall, and Fig. 6 shows the joint end of the retaining wall block. A partial plan cross-sectional view showing an enlarged joint part,
FIG. 7 is a partially enlarged plan sectional view of the seal groove portion, and FIG. 8 is an enlarged sectional view of the interior of the coupling box. n... Center line, 1... First retaining wall block, 1
a...Inner circumferential surface, 1b...Outer circumferential surface, 2...Second retaining wall block, 2a...Inner circumferential surface, 2b...Outer circumferential surface,
3... Peripheral wall, 3a... Base part, 4... Bottom plate, 4a
... recess, 5, 6 ... flange, 7 ... joint end surface, 8, 9 ... joint end surface, 10 ... slope section, 11
...Joining end surface, 12, 13...Outward surface portion, 14...
...Slope portion, 15, 16...Seal groove, 15a, 1
6a... wide groove, 15b, 16b... narrow groove, 1
7... Sealing material, 18... Connection box, 19
...Through hole, 20...PC steel material (PC steel rod), 20
a, 20b...Thread part, 21...Anchor plate, 22...Nut, 23...Foundation, 24...Foundation chestnut stone, 25...Foundation concrete, 26...Mortar laying, 27...Anchor rod, 28... ...Slip line.

Claims (1)

[Claims] 1 A perfectly circular peripheral wall formed by arranging first retaining wall blocks and second retaining wall blocks alternately in the circumferential direction is erected on the foundation, and the surrounding wall is backfilled with soil. The first retaining wall block is integrally connected to the foundation, and an adjacent second retaining wall block is connected to the joint end surfaces at both ends of each of the first retaining wall blocks. A locking surface part is provided to prevent the retaining wall block from moving outward,
A circular underground water tank characterized in that a sealing material is interposed between the joint end face of the first retaining wall block and the joint end face of the second retaining wall block at a portion corresponding to the locking surface portion.