JPH07156992A - Underground storage facility - Google Patents

Abstract

(57) [Summary] [Purpose] When constructing a storage tank for water utilization underground, it is possible to significantly reduce the manufacturing cost while ensuring the necessary functions. [Structure] The ground is excavated by dry excavation using a deep well or wet excavation by the completion method to form a storage space 2 having a predetermined volume. After the lower surface of the water shield sheet or concrete 4 is applied to the excavated surface of the storage space 2, the storage space 2 is filled with crushed stones 5 such as debris. A water supply / drainage facility 6 is provided in the crushed stones 5, and an upper water-blocking work 7 of a water blocking sheet or concrete and an air bleeding facility 8 are provided on the upper surface of the crushed stones 5. Water supplied from the outside is quickly filled and stored in the voids of the crushed stones 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground storage facility applied to an underground water supply dam or the like.

[0002]

2. Description of the Related Art For example, when constructing a dam for water use by utilizing underground such as a wetland, when a pond is simply constructed, environmental problems occur. For this reason, the need for an underground dam arises. As a conventional underground water dam, a tunnel-type storage tank 50 by the shield construction method as shown in FIG. 6 or a ground structure obtained by excavating the ground is provided. There is an RC storage tank 60 for manufacturing

[0003]

However, in the case of constructing a storage tank with a shield tunnel or a concrete structure in the conventional ground as described above, it stands up against earthquakes, earthquakes, etc. from the viewpoint of being a permanent structure. However, depending on what is stored, it is an over-investment, and there is a problem in cost, which is a major bottleneck in business.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide an underground storage facility capable of significantly reducing the manufacturing cost of an underground storage tank while ensuring necessary functions. To do.

[0005]

The present invention is a system for storing water by utilizing voids such as crushed stone instead of constructing a cavity with a tunnel or concrete. Specifically, the ground is excavated to form a storage space, and the excavated surface of this storage space is subjected to a lower water shield (water shield sheet or concrete, etc.) Is filled with crushed stones such as debris, and if necessary, the upper surface of this crushed stone is covered with water (impermeable sheet or concrete).

[0006]

With the above-mentioned structure, water is supplied from the outside into the storage space filled with crushed stones. The supplied water is filled in the voids of crushed stones. If the volume of the storage space is V and the porosity of the crushed stones is n, a storage amount of V × n can be obtained.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. 1 (a) and 1 (b) are schematic cross-sectional views showing an outline of an underground storage facility of the present invention, and FIGS. 2 and 3 are cross-sectional views showing an example of a dry excavation method using a deep well, plan views, and FIG. , Fig. 5
[Fig. 3] is a cross-sectional view and a plan view showing an example of a wet excavation method by the completion method.

As shown in FIGS. 1 (a), 2 and 3, the dry excavation type underground storage facility 1 includes a storage space 2 and an impermeable wall 3.
It is composed of a lower water shield 4, a crushed stone 5, a water supply / drainage facility 6, an upper water shield 7, and an air vent equipment 8.

The storage space 2 is an inverted quadrangular truncated pyramid space in which the silt layer a is excavated, the gravel layer b is the bottom surface 2A, and two side slopes 2B are formed on the side surfaces. Crushed stones 5 capable of ensuring a porosity n of, for example, about 0.25 to 0.37 are put into the storage space 2.

Here, the storage space 2 has an effective volume V thereof.
However, when the effective water storage amount is W, excavation may be performed so as to be W / n. For example, the storage space 2 is about 2000 m square, the effective storage height (H) is about 11 m, and the porosity is 0.2.
If it is set to 5, a storage amount of about 10 million m ³ can be obtained.

The impermeable wall 3 is a continuous underground wall without a core (SM
(W), the silt / fine sand alternating layers c are driven so as to surround the storage space 2, and the intermediate partition impermeable wall 3a is further constructed if necessary. The surface improvement process 9 is applied to the slope 2B.

The lower water shield 4 is a crushed stone 4A (thickness 300 m
m) and concrete 4B with mesh on this
(Thickness about 200 mm), bottom surface 2A and slope 2
Install on B.

The water supply / drainage facility 6 is composed of a cylindrical water supply / drainage pit 6A which is vertically erected in the storage space 2 and a blind water supply / drainage pipe 6B embedded in the paving stone 5 '. Blind drainage pipe 6B
Is provided at the bottom of the storage space 2 by, for example, arranging a large number of water supply / drain holes in the lower part, and has one end communicated with the lower part of the water supply / drain pit 6A to supply water into the storage space from the outside and from the storage space to the outside. Allow drainage.

A large number of blind water supply / drainage pipes 6B are arranged in parallel at a pitch of, for example, about 100 m, and water supply / drainage pits 6A are also arranged correspondingly.

The upper water shield 7 is arranged at a predetermined depth from the ground GL, and is constructed by providing a rubber water shield sheet 7A having a thickness of about 2 mm on the protective layer 7B. Further, the air vent pipe 8A of the air vent facility 8 is provided in the protective layer 7B. The air vent pipe 8A is for discharging the air in the void of the crushed stones 5 to the outside when the void is filled with water. The end is exposed to the outside.

With the above-mentioned structure, the dry construction is performed in combination with the deep well as follows.

(1) Preparation work is performed at the installation position of the underground storage tank.

(2) The impermeable wall 3 and, if necessary, the partition wall impermeable wall 3A are built in the ground.

(3) A deep well is provided inside the impermeable wall 3, and underground water in the impermeable wall 3 is pumped up by the deep well to improve the silt layer a.

(4) Excavating the inside of the impermeable wall 3 to store the storage space 2
To form.

(5) Surface treatment 9 on the slope 2B of the storage space 2
Give.

(6) Crushed stone 4A is spread on the bottom surface 2A and slope 2B of the storage space 2, and concrete 4B is paved on this.

(7) A blind drainage pipe 6B is provided on the bottom surface 2A.

(8) Crushed stones (debris) 5 are put into the storage space 2 provided with the lower water-blocking work 4.

(9) An air vent pipe 8A is provided on the upper surface of the crushed stones 5, a protective layer 7B is laid, and a water barrier sheet 7A is laid on the protective tank 7B.

(10) The water impervious sheet 7A is covered with, for example, 2 m of soil 10 to restore the original shape.

In the underground storage tank 1 constructed as described above, water is supplied and drained as follows.

Water is supplied to the water supply / drainage pit 6A from the outside.

The supplied water is filled in the voids of the crushed stones 5 through the blind drainage pipe 6B. At this time, the air in the void is discharged to the outside by the air vent pipe 8A, and the supplied water is quickly filled in the void.

The stored water passes through the blind supply / drain pipe 6B and is discharged to the outside from the water supply / drain pit 6A. Also in this case, air can be supplied from the outside by the air vent pipe 8A and quickly discharged.

Next, as shown in FIG. 1 (b), FIG. 4 and FIG. 5, the wet excavation type dry excavation type underground storage facility 11 according to the completed construction method has a storage space 12 and an impermeable wall 13. The lower water shield 14, the crushed stones 15, the water supply / drainage equipment 16, the upper water shield 17, and the air bleeding equipment 18.

The storage space 12 is formed in a rectangular parallelepiped shape by excavating the silt layer a in the impermeable wall 13 and using the gravel layer b as the bottom surface 12A and the impermeable wall 13 as the side surface. The crushed stones 5 similar to the dry type described above are put into the storage space 12.

The impermeable wall 13 is also a soil retaining wall and is a continuous underground wall (SMW) in which H-shaped steel is arranged in the core. It is driven into the gravel layer b and the upper end of the earth anchor 19 is gravel layer b. Fixed to. In addition, this earth retaining wall is not limited to this and may be of another type.

The lower water shield 14 is provided with an asphalt mat 14A (thickness: about 50 mm) or a civil engineering sheet, which is laid if necessary, and an underwater concrete 14B thereon.
(Thickness of about 500 mm) and is applied to the bottom surface 12A.

The water supply / drainage facility 16 is composed of a water supply / drainage pit 16A and a blind water supply / drainage pipe 16B, similarly to the dry type.
The upper water shield 17 is also composed of a water shield sheet 17A and a protective layer 17B, and an air vent pipe 18A is arranged in the protective layer 17B.

With the above-mentioned structure, the wet construction using the completed construction method is performed in the concept of sea construction as follows.

(1) Preparation work is performed at the installation position of the underground storage tank.

(2) The impermeable wall 13 is built underground.

(3) The lower part of the earth anchor 19 is covered with a gravel layer b.
Then, the upper part is connected to the upper end of the impermeable wall 13.

(4) Completion of the inside of the impermeable wall 13 and storage space 12
To form.

(5) An asphalt mat 14A is laid on the bottom surface 12B of the storage space 12.

(6) The underwater concrete 14B is placed on the asphalt mat 14A.

(7) A blind drainage pipe 16B is provided on the bottom surface 12A, and crushed stones 15 "are spread to a thickness of about 2 m.

(8) Crushed stones (debris) 15 on crushed stone 15 "
Throw in.

(9) The air vent pipe 18A on the upper surface of the crushed stones 15
And the protective layer 17B is laid, and the waterproof sheet 17A is laid on the protective tank 17B.

(10) For example, 2 m above the impermeable sheet 17A
Cover it with the soil 20 and restore the original shape.

[0047]

As described above, the underground storage facility of the present invention excavates the ground surface, and puts crushed stones into the storage space with the excavation surface provided with a water shield to store water in the voids of the crushed stones. Since it is configured to be filled with, it is not necessary to take measures against floating or earthquake unlike the conventional tunnel type or RC type underground storage tank, and most of it can be composed of crushed stones,
It is possible to significantly reduce the manufacturing cost of the underground water tank while ensuring the required functions.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an outline of an underground storage facility of the present invention. (a) shows the case where the side surface of the storage space is a slope, and (b) shows the case where the side surface of the storage space is a retaining wall.

FIG. 2 is a cross-sectional view showing an example of a dry excavation type underground storage facility using the deep well of the present invention.

FIG. 3 is a plan view of FIG.

FIG. 4 is a cross-sectional view showing an example of a wet excavation type underground storage facility by the completion method of the present invention.

FIG. 5 is a plan view of FIG.

FIG. 6 is a schematic sectional view showing a conventional underground storage tank.
(a) shows a tunnel type and (b) shows an RC underground storage tank.

[Explanation of symbols]

1 ... Dry excavation type underground storage facility 2 ... Storage space 2A ... Bottom surface 2B ... Slope 3 ... Impermeable wall 3A ... Partition partition impermeable wall 4 ... Lower impermeable work 4A ... Crushed stone 4B ... Concrete 5 ... Crushed stones 6 ... Water supply / drainage equipment, 6A ... Water supply / drainage pit, 6B ... Blind water supply / drainage pipe 7 ... Upper water shield, 7A ... Water shield sheet, 7B ... Protective tank 8 ... Air venting equipment, 8A ... Air venting pipe 9 ... Surface treatment Construction 10 ... Covering soil 11 ... Wet excavation type underground storage facility 12 ... Storage space 2A ... Bottom surface 13 ... Impermeable wall (earth retaining wall) 14 ... Lower impermeable construction, 14A ... Asphalt mat, 14
B ... Underwater concrete 15 ... Crushed stone 16 ... Water supply / drainage equipment, 16A ... Water supply / drainage pit, 16B ... Blind water supply / drainage pipe 17 ... Upper water barrier, 17A ... Water shield sheet, 17B ... Protection tank 18 ... Air venting equipment, 18A ... Air venting Tube 19 ... Earth anchor 20 ... Soil cover

Claims (1)

[Claims] 1. The ground is excavated to form a storage space, the excavated surface of the storage space is subjected to a lower water shield, and the lower storage space is filled with crushed stones, which is required. An underground storage facility characterized by an upper water-blocking work on the upper surface of the crushed stones according to.