JP3355438B2 - Underground tank structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an underground tank.

[0002]

2. Description of the Related Art As shown in FIGS. 3 and 4, a conventional underground tank has a side wall a and a bottom plate b surrounded by a continuous underground wall d.
And the configuration. And joint c between side wall a and bottom plate b
Are provided, and the two are separated from each other. Therefore, excessive stress concentration did not occur at the lower end of the side wall. However, in the structure in which the joint is interposed between the side wall a and the bottom plate b, there are problems that the structure is complicated and that there is a possibility that groundwater may enter. Therefore, the present inventors have proposed an underground tank having a structure in which the side wall a and the bottom plate b are rigidly connected as shown in FIG.

[0003]

The underground tank having a structure in which the side wall a and the bottom plate b are rigidly connected has many features, but has the following problems. <B> As shown in FIG. 5, a portion f where the stress is concentrated on the lower end portion of the side wall a by making the side wall a and the bottom plate b rigidly connected.
Occurs. <B> In order to counter stress concentration occurring at the lower end of the side wall, the reinforcing bars must be densely arranged. <C> Due to the dense arrangement of the reinforcing bars, the fluidity of the concrete may be hindered.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems, and has an advantage of rigidly connecting a side wall and a bottom plate, while avoiding the arrangement of a dense reinforcing bar. It is an object of the present invention to provide a structure of an underground tank.

[0005]

In order to achieve the above object, the structure of an underground tank according to the present invention is an underground tank of a hydraulic pressure resistant version, wherein the underground tank is constituted by a side wall and a bottom plate, and The joint between the side wall and the bottom plate is rigidly connected, and the bottom surface of the bottom plate has a large number of spherical surfaces projecting downward.
It is characterized by comprising a set of planes .

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the structure of an underground tank according to the present invention will be described below with reference to the drawings.

<A> Preconditions The underground tank of the present invention is an underground tank made of reinforced concrete of a water-resistant strength version type. This “water pressure resistant version” type underground tank is an underground tank provided with a bottom plate 1 that strongly resists the underground water pressure p. Bottom plate 1 of this type is a depressurized version of an underground tank in which groundwater pressure does not act on the bottom plate,
Or, unlike the above-ground tank, it is surrounded by groundwater. For this reason, it is required for the underground tank of the water pressure resistant strength type to have high waterproofness.

<B> Construction of an underground tank. When constructing an underground tank, generally, first, a continuous underground wall 2 is constructed around the construction area of the tank and water is stopped. Next, the area surrounded by the continuous underground wall 2 is excavated to the lower surface of the bottom slab 1.
Next, the concrete of the bottom slab 1 is cast and the concrete of the side walls 3 is cast to complete the tank. A membrane 4 is attached to the inside of the side wall 3 via a cold insulator. A bottom heater 5 is generally disposed inside the bottom plate 1. However, the continuous underground wall and the bottom heater are not necessarily required.

<C> Rigid connection between the side wall and the bottom plate. As described above, the underground tank includes the reinforced concrete side walls 3 and the bottom slab 1. Particularly, in the underground tank of the present invention, no joint is provided between the side wall 3 and the bottom plate 1. The two are rigidly connected without any joints. The structure to be a rigid connection can be constructed by a conventionally known method. Thus, no joint is provided at the connection between the bottom plate 1 and the side wall 3, and a rigidly connected underground tank is completed.

<D> Shape of the bottom plate. The bottom plate 1 has its lower surface 5 formed in a shape protruding downward. That is, the center of the bottom slab 1 is projected most downward,
A large number of inclined surfaces are formed around it. Therefore, the lower surface 5 of the bottom slab 1 has a shape as if a spherical surface was formed by a set of many planes. The upper surface of the bottom plate 1, that is, the bottom of the tank, does not necessarily need to be formed in a polygonal shape in accordance with the lower surface 5 of the bottom plate 1, and may be formed in a plane or a polyhedron different from the lower surface 5 of the bottom plate 1. Bottom plate 1
By projecting the lower surface 5 downward, the flow of stress in the attachment portion between the side wall 3 and the bottom plate 1 can be made smooth, and an excessive bending moment generated in the attachment portion between the side wall 3 and the bottom plate 1 can be reduced.

[0011]

As described above, the structure of the underground tank according to the present invention is constituted by rigidly connecting the side wall of the underground tank of the pressure-resistant strength type and the bottom plate, and the lower surface of the bottom plate is projected downward. The following effects can be obtained because of the polyhedral structure. <B> There is no joint between the side wall and the bottom slab. Therefore, the structure is simple, the assembling of the reinforcing steel bar and the formwork can be easily and economically performed, and the construction period can be shortened. <B> Since there is no joint between the side wall and the bottom slab, there is no possibility that surrounding groundwater or the like will enter the inside of the tank through the joint, and high watertightness is ensured. <C> Excessive bending moment generated at the joint between the bottom plate and the side wall formed so that the lower surface of the bottom plate protrudes downward can be reduced. Therefore, the rebar does not concentrate on the lower part of the side wall. Therefore, the phenomenon of concrete flow obstruction, which is likely to occur in places where the rebar is overcrowded, does not occur,
A highly reliable underground tank made of concrete can be obtained. <D> Since the bottom surface of the bottom plate is formed not as a curved surface but as a polyhedron, which is a collection of many planes, assembling of the formwork is easier than in the case of forming a curved surface, and an underground tank can be constructed economically. be able to.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an embodiment of the structure of an underground tank according to the present invention.

FIG. 2 is an explanatory diagram of a bottom plate.

FIG. 3 is an explanatory view of an embodiment of the structure of a conventional underground tank.

FIG. 4 is an explanatory view of a joint of a side wall and a bottom plate of a conventional underground tank.

FIG. 5 is an explanatory view of an embodiment of another invention proposed by the present inventors.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Taira Yamamoto 1-25-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo Inside Taisei Corporation (56) References JP-A 52-6118 (JP, A) JP-A Hei 6-346620 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B65D 90/08 B65D 88/76 E02D 29/045 E21D 13/00

Claims (1)

(57) [Claims] An underground tank of a water-resistant strength type, wherein the underground tank comprises a side wall and a bottom plate, and a joint between the side wall and the bottom plate is rigidly connected, and a lower surface of the bottom plate protrudes downward. Many spherical surfaces
Underground tank structure composed of a collection of planes .