JPH0546798U - Underground tank with floating prevention structure - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an underground tank that is easy to construct and re-drill. [Structure] The underground tank is provided with a flange or flange projecting outward in the radial direction, and is buried using soil cement.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a floating prevention structure for an underground tank such as a masu, septic tank, oil tank, and water tank for sewage buried underground.

[0002]

[Prior Art]

 As is well known, underground tanks installed underground may float due to the effects of fluidization of groundwater and sand. Especially when installing a lightweight material, such as a plastic underground tank, in a place where the groundwater level is high, the tendency is remarkable when the content is small. Therefore, conventionally, a concrete molded product is placed on the underground tank, or a concrete structure is installed on the bottom of the underground tank, and the bottom of the underground tank is fixed to the concrete structure with an anchor material to raise the underground tank. Had been prevented.

However, when a concrete molded product or a structure is produced, a special means such as a heavy machine is required for carrying in or constructing, and the work is troublesome because the weight and volume are large. Moreover, once a concrete structure is constructed, it is difficult to excavate and dig again.

[0004]

[Problems to be Solved by the Invention]

 Therefore, an object of the present invention is to provide an underground tank having a levitation prevention structure, which is easy to construct and re-drill and yet has sufficient sewage use, and which can prevent underground tanks such as septic tanks, oil tanks and water tanks from rising. It is in.

[0005]

[Knowledge]

 As a result of various studies, the present inventor has found that it is effective to use soil cement as a weight for preventing floating of an underground tank. Soil cement is usually used for the improvement of soft ground and the safety treatment of roads and roadbeds, and is a mixture of about 5-10% cement with sand. This soil cement has a higher uniaxial compressive strength than sand, has a large internal friction angle, does not fluidize, and can be dug using a scoop even after solidification. However, the adhesive strength with the underground tank is inferior to that of concrete. Therefore, according to the present invention, the underground tank is prevented from floating by having the following configuration.

[0006]

[Means for Solving the Problems]

 According to the present invention, in an underground tank made of a lightweight material and having a floating prevention structure buried in the ground, a flange outwardly protruding in the radial direction is provided at the middle of the main body in the vertical direction, and the lower part of the main body is provided. A plurality of flanges are provided on the inner side of the main body so as to project outward in the radial direction, and soil cement that constitutes the weight is embedded in the flange or the flange by engaging with the soil cement.

[0007]

[Explanation of effects]

 Therefore, first dig a predetermined hole, and before installing the underground tank in the hole, as a foundation, first add soil cement to position the underground tank slightly away from the bottom of the hole. Then, the soil cement is put into the hole so that the plural brims are filled, and earth and sand are put above the soil cement to bury the underground tank.

[0008] In some cases, soil may be poured up to the flange of the main body, and soil cement may be added above it.

[0009] In the former case, even if a plurality of brims are sufficiently supported by soil cement and the buoyancy caused by groundwater occurs in the underground tank, the weight of soil cement supports the underground tank, so the underground tank floats. There is nothing to do.

Further, in the latter case, the weight of the soil cement is applied by the flange protruding outward in the radial direction, and the floating is also prevented.

As described above, since soil cement has a large internal friction angle, it is possible to apply the entire weight to the brim or flange, and since it can be dug up with a scoop or the like, there is a problem in repair and the like. There is no.

[0012]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. In FIG. 1, an underground tank generally designated by A is a plastic wastewater tank, which is formed in a generally cylindrical shape, and its main body is It is composed of an upper part 1a and a lower part 1b, and is integrally composed of a flange 2 which is provided in the middle and projects outward in the radial direction. A top portion 3 is formed at the upper end of the main body portion 1, and a downwardly projecting upper cylinder portion 4 is attached to the lower portion of the main body portion 1. The outer periphery of the upper cylinder portion 4 is provided with a plurality of triangular flanges 5. It is integrally formed so as to project out of the direction.

When burying the underground tank 1, a hole H is excavated from the ground surface GL, and first, soil cement S is charged to leave the underground tank A from the bottom portion B of the hole H to the lower portion of the tubular body 4 to be dried. Install at a distance X. Then, to the depth L where the brim 5 is buried, the soil cement S of a weight sufficient to overcome the buoyancy is introduced, and then the earth and sand D is introduced to the upper part thereof to bury the underground tank A. The mix of soil cement S is determined by the mix experiment before using the sand to be used. Also, be careful that the soil cement S is sufficiently filled in the lower side of the underground tank A, and so-called "su" cannot occur. Further, after the soil D is backfilled, it is sufficiently compacted with, for example, a stick or a wooden ledge, and after the backfilling is completed, the area around the underground tank A is compacted by a rammer or a wooden ledge. When backfilling the sediment D, the level TL above the underground tank A is set higher by a height δ than the ground surface GL so that rainwater and the like do not flow into the underground tank A. A manhole 6 is installed on the top of the underground tank A.

Therefore, even if the groundwater level WL rises and the buoyancy F acts on the underground tank A, since the underground tank A is integrated with the soil cement S via the brim 5, the weight of the soil cement S is buoyant. Underground tank A does not rise after defeating F.

FIG. 2 shows another embodiment of the present invention. In this example, the lower part of the underground tank A is backfilled with earth and sand D, and the soil cement S is put in the upper part of the flange 2. The other configurations are similar to those of the example of FIG.

In this example, the soil cement S and the underground tank A can be integrated by the flange 2 and the underground tank does not float.

[0017]

[Effect of the device]

 As described above, the present invention has the following excellent effects.

(1) Since soil cement has a large internal friction angle, the brim or flange protruding outward in the radial direction can sufficiently prevent the underground tank from floating.

(2) After construction, it can be dug again with a scoop, for example, and repair and repair are easy.

(3) The burying work is simple, can be performed in a short time, and is inexpensive.

(4) It can be buried even in a narrow space.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a side sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 1 ... Main part 1a ... Upper part 1b ... Lower part 2 ... Flange 3 ... Top part 4 ... Cylindrical part 5 ... Collar 6 ... Manhole A ... Underground tank B・ ・ ・ Bottom D ・ ・ ・ Soil and sand H ・ ・ ・ Hole S ・ ・ ・ Soil cement

Claims (1)

[Scope of utility model registration request] 1. In an underground tank made of a lightweight material and having a floating prevention structure buried in the ground, a flange protruding outward in the radial direction is provided in the middle of the main body in the vertical direction,
Floating prevention, characterized in that a plurality of collars projecting outward in the radial direction from the main body are provided in the lower portion of the main body, and soil cement constituting the weight is embedded by engaging with the flange or the collar. Underground tank with structure.