JPH0941435A - Cistern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cistern usable even when the concrete foundation of the cistern is cracked by point-fixing a bag-like sheet only in the upper surface part of the cistern, and annularly providing and fixing a flexible soft foam between the side wall head part of the cistern and the bag-like sheet. SOLUTION: A synthetic resin sheet formed bag 7 is provided on the inner part of a cistern 10. The synthetic resin sheet formed bag 7 is point-fixed only in a cistern upper surface part 10d by an anchor vis 8. A flexible soft foam 6 is annularly provided and fixed between the cistern side wall part 10b and the bag 7. The bag sheet 7 has a physical characteristic of elongation of 50% or more. To protect the bag sheet 7, a protecting layer 4 is point-fixed to the cistern side wall part 10b and the cistern bottom part 10a by adhesive or anchor vis 8. Further, back water or spring water is stored in a storage valve 9 on the bottom part 10a through a clearance, and pumped onto the ground by a pump 2 when it reaches a fixed quantity. The action of buoyancy is prevented thereby. Thus, an inexpensive cistern never influenced by the crack of a foundation 1 can be provided.

Description

Detailed Description of the Invention

[0001]

[Industrial application] The present invention relates to a concrete water tank used for fire prevention water, drinking water, and the like.

[0002]

2. Description of the Related Art As a general water tank for concrete such as water for fire protection and drinking water, a contact type protective layer such as epoxy paint or polyester FRP (Fibre Rei) for the purpose of protecting reinforced concrete structure and reinforced concrete.
In many cases, it has been subjected to nforced plastics). These structures have been used for normal use without any problems, but in the event of a major earthquake, the concrete foundation and protective layer also cracked due to ground subsidence and shaking,
Do not use in an emergency because it will leak water. 5 and 6 are cross-sectional views of a conventional water storage tank, but even if a protective layer such as epoxy coating (Fig. 5) or FRP coating (Fig. 6) on the inner surface of the concrete base is provided, the backwater is prevented from springing. Thicker epoxy and FRP coatings are required. However, the thicker it is, the more costly it is, which is not desirable.

[0003]

At present, there are the following drawbacks. 1) The adhesion method cannot withstand cracks of 5 mm or more. 2) In the conventional floating sticking method, buoyancy acts on the waterproof layer due to the spring water of the back surface of the base, so that the waterproof layer is damaged. 3) The tank such as FRP may be buried, but the cost is high. 4) Leakage and backwater intrusion due to cracks due to ground subsidence during the Great East Japan Earthquake have not been addressed.

[0004]

Means for Solving the Problems The present invention has been achieved as a result of earnest research to solve the above problems. The present invention is a concrete underground water tank in which a bag-shaped synthetic resin sheet is internally installed. In the above, the bag-shaped sheet is point-fixed only at the upper surface portion of the water tank, and the flexible soft foam is rotatably fixed to the side wall head of the water tank and between the bag-shaped sheet and Further, the bag-shaped sheet has a physical property of an elongation rate of 50% or more, and further, spring water and back surface water generated from the side wall and the bottom of the water storage tank are stored in a storage box provided at the bottom of the water storage tank. It is a water tank that can be discharged from the rear pumping pump to the drain on the ground.

That is, the present invention is as follows. 1) A heat-sealable thin synthetic resin sheet having a thickness of 0.5 to 3 mm is formed into a bag shape and attached without adhering to the side wall portion and the bottom portion. 2) Float the synthetic resin sheet bag to fix it,
A soft foam is provided in the shape of a ring on the side wall of the water tank in order to provide a clearance for the waterproof layer due to ground subsidence. 3) A protective layer is provided on the side wall and bottom to protect the synthetic resin sheet bag from damage due to projections that occur when the concrete base cracks. 4) Install a drainage device and a drainage pipe to draw out the back water.

The present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the water tank of the present invention, showing a conventional concrete base 1
By installing a synthetic resin sheet bag 7 inside instead of epoxy coating (Fig. 5) and FRP coating (Fig. 6) on the inner surface of
It corresponds to the back water. The synthetic resin sheet used in the present invention is preferably a thin fusible sheet having a thickness of 0.5 to 2.5 mm. As the material of the synthetic resin sheet, thermoplastic polyurethane, polyvinyl chloride, polyethylene and polypropylene are used.

The synthetic resin bag-like sheet used in the present invention is more preferably a sheet having an elongation rate of 50% or more. This sheet is more effective for leaking stored water due to severe ground subsidence.

According to the method of installing the synthetic resin sheet bag 7 of the present invention, the anchor screws 8 and the like are fixedly attached to the upper surface portion 10d of the water tank. In some cases, a metal bar is used and fixed with an anchor screw, but the metal bar coated with the heat-sealing resin may be screwed first, and the bag-shaped sheet may be heat-sealed to the coated metal bar.

In the present invention, even if the ground subsides due to an earthquake or the like and a crack of about 100 mm is generated in the water tank base, the synthetic resin sheet bag 7 can follow the soft foam on the water tank head 10c. An object having a semicircular or semielliptical or quadrangular shape having a sectional shape of 6 is placed and fixed in a ring shape. Adhesive fixing is desirable as the fixing method. The cross-sectional dimension of the flexible foam required to secure a 100 mm drop margin is
For example, in the case of a semicircular shape having a diameter D, 3.14D / 2-D = 100 D = 100 × 2 / 1.14≈176 mm, and a semicircular flexible foam having a cross-sectional shape with a diameter of 180 mm or more is used. The apparent density of flexible foam is 15 kg / m ³ ~
50 kg / m ³ is desirable, and as the flexible foam, flexible polyurethane foam or polystyrene foam is used.

When the base is cracked due to the great earthquake, a protective layer 4 is provided on the water tank side wall portion 10b and the bottom portion 10a in order to protect the synthetic resin sheet bag 7 formed by the protrusions on the water tank side wall portion 10b and the bottom portion 10a. It is point-fixed with an adhesive or anchor screw 8. The thickness of the protective layer is preferably 3 to 50 mm, and the material thereof is preferably polypropylene, polyester non-woven fabric, glass wool, coconut fiber wool or a laminate thereof, and may be short fiber or spunbond.

FIG. 2 is an enlarged view of portion A of FIG.
FIG. 6 is a diagram for explaining the function of the. The reason why the water tank 10 can be used in spite of the crack caused by the great earthquake is that the synthetic resin sheet bag 7 is stretched to the bottom portion 10a by the compression of the flexible foam 6 and can cope with the crack. . For this reason, the anchor screws 8 fix the spots on the upper surface portion 10d at the position where the flexible foam 6 is mounted and fixed.

FIGS. 3 and 4 are cross-sectional views showing the correspondence of the synthetic resin sheet bag 7 installed in the water storage tank 10 when a crack K is generated in the water storage tank base 1 due to the subsidence of the ground due to the earthquake. That is, if a crack K occurs in the water tank base 1 due to subsidence due to the earthquake, the depth of the water tank base increases,
Due to the weight of the stored water, the synthetic resin bag tries to drop toward the bottom portion 7 of the water storage tank, and stress is generated between the side wall head and the fixed portion. At this time, the elastic force of the flexible foam of the present invention (cushioning property). ) Alleviates this stress, and plays the role of a drop margin. As shown in FIG. 4, the crack is formed on the side wall 10 of the water tank.
When it occurs at the bottom b and the bottom portion 10a, the falling margin follows the crack due to the synergistic effect of the stretch of the compressed flexible foam and the synthetic resin sheet bag 7 and prevents leakage of the stored water.

Incidentally, the side wall portion 10b and the bottom portion 10a of the water tank.
The synthetic resin sheet bag 7 and the synthetic resin sheet bag 7 are not adhered to each other to form a gap, and the back water and the spring water are stored in the back water surface reservoir 9 at a corner of the water tank bottom portion 10a through the gap, and when a certain amount is reached, the back water surface drawing pump 2 works and drainage pipe 3 through drainage pipe 1 above ground
Suck up to 3. In the present invention, the back water is stored and drained at the bottom because the back pressure is applied to the synthetic resin sheet bag when the back water is stored and the bag is deformed or floats, so that the water storage effect is lowered and the back pressure is applied to the bag. This is to prevent the synthetic resin sheet bag from being damaged due to concentrated stress on the upper fixed anchor screw 10c.

[0014]

【The invention's effect】

1) Influences cracks in the concrete base by forming a thin, fusible synthetic resin sheet with a thickness of 0.5 to 2.5 mm on the inner surface of the water storage tank while fusing it without adhering it to the concrete base. A cheap water storage tank can be obtained. 2) By selecting a slippery protective layer for the concrete base and synthetic resin sheet bag, it is possible to obtain a water tank that can cope with cracks of 100 mm or less. 3) Since the flexible foam was placed and fixed in a ring shape on the head portion of the side wall of the water storage tank, the flexible foam was compressed against the occurrence of cracks, and the synthetic resin sheet bag could be stretched and dealt with. 4) A drain pipe is provided between the concrete base and the bag made of synthetic resin sheet, and the back water is stored in the back water reservoir provided at the bottom of the water tank, and when it reaches a certain amount, it is sucked up to the above-ground drain ditch through the drain pipe. , While preventing buoyancy from working,
Since the bag made of synthetic resin can be prevented from being deformed, the water storage effect is improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a water tank of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a cross-sectional view showing the follow-up of a water storage tank and a synthetic resin sheet bag corresponding to cracks in the water storage tank base due to subsidence due to the earthquake.

FIG. 4 is another cross-sectional view showing the follow-up of the water storage tank and the synthetic resin sheet bag corresponding to the crack of the water storage tank base due to the ground subsidence caused by the earthquake.

FIG. 5 is a cross-sectional view of a conventional water storage tank.

FIG. 6 is a cross-sectional view of another conventional water storage tank.

[Explanation of symbols]

 1 Water Reservoir (Concrete) Base 2 Back Water Pumping Pump 3 Drain Pipe 4 Protective Layer 5 Adhesive Layer 6 Soft Foam 6a Compressed Flexible Foam 7 Synthetic Resin Sheet Bag 8 Anchor Screw 9 Back Water Reservoir 10 Water Reservoir 10a Water Reservoir Bottom 10b Water Reservoir Tank side wall part 10c Water tank side wall head part 10d Water tank upper surface part 11 Paint surface application surface 12 FRP application surface 13 Drain groove D Soft foam cross-sectional diameter E Land K Crack W Water

Claims (3)

[Claims] 1. A concrete underground water tank with a bag-shaped synthetic resin sheet inside: 1) The bag-shaped sheet is fixedly attached only to the upper surface of the water tank. 2) The side wall head of the water tank. A water tank capable of coping with ground subsidence, characterized in that a flexible soft foam is rotatably fixed between the bag-shaped sheet and the concrete at the section. 2. The physical properties of the bag-shaped sheet have an elongation rate of 50%.
The water tank according to claim 1, which is the above. 3. Spring water (back surface water) generated from the side wall and bottom of the water storage tank is stored in a reservoir provided at the bottom of the water storage tank,
The water tank according to claim 2, wherein the water is discharged from the back side pumping pump to a drainage groove on the ground.