JPH0734711A - How to construct a thin metal underground tank - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To construct an underground tank for heat storage economically in a deep drill hole. [Structure] A bottom cover portion 6 of an underground tank made of a thin-walled metal is floated in the hole wall protection liquid 3 in the deep-drilled hole, and the body unit 7 divided into a number of stages is repeatedly joined and sunk to form an underground tank. To build. In this step, a weight 8 for adding the own weight of the underground tank to the buoyancy of the underground tank and the difference between the buoyancy adjusting water 5 and the buoyancy of the underground tank is arranged in this step, and the fuselage unit is joined at a predetermined position on the ground. Done in.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a large-scale thin metal underground tank for storing heat such as hot water or cold water in a deep hole drilled in the ground.

[0002]

2. Description of the Related Art Storing liquids such as hot water and cold water in an underground tank is an effective means because the heat insulating effect in the ground can be utilized and expensive land rent can be saved. The effect increases. In addition, the underground tank can balance the internal pressure of the liquid stored in the tank and the external pressure of the ground water, and thus has the effect of reducing the tank plate thickness.

In the method of constructing an underground tank disclosed in Japanese Patent Laid-Open No. 63-147070, a vertical hole is excavated while protecting the hole wall with a hole wall protective liquid, and the hole wall protective liquid in the vertical hole is Float the bottom lid part of the underground tank to the bottom lid part, join the body unit of the underground tank to the bottom lid part, and sequentially attach a predetermined number of body units until the underground tank of a predetermined length is sunk in the vertical hole. Join together.

In the process of this construction, a buoyancy adjusting liquid for adjusting the sinking amount of the underground tank by partially reducing the buoyancy by the hole wall protection liquid so that the fuselage unit can be joined at a predetermined position on the ground. It is poured into the underground tank under construction, and after all the joining and sunk of the underground tank are completed, the grout material is filled in the gap between the outer peripheral surface of the underground tank and the hole wall of the vertical hole.

However, in an underground tank having a thin plate, the weight of the underground tank is relatively small. Therefore, the buoyancy of the underground tank that is received from the hole wall protection liquid at the time of sinking is the weight of the underground tank. And the weight of the buoyancy adjusting liquid in the underground tank is exceeded, in order to allow the underground unit to settle until the joint part of the uppermost fuselage unit reaches a predetermined position on the ground with good workability, The amount corresponding to the difference between the buoyancy and the total weight will be insufficient.

As a measure for compensating for this insufficient weight, a method of increasing the plate thickness to increase the own weight of the underground tank,
A method of using a liquid having a large specific gravity as a buoyancy adjusting liquid has been considered. In the former solution, the material cost of the underground tank,
While the costs of processing and joining between fuselage units increase, the latter solution requires the use of liquids with a higher specific gravity than water, but such liquids are expensive and must be recovered after use. There is a big problem at the disposal stage. Both increase the cost of building underground tanks and impair the economic efficiency.

[0007]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to use water which is cheap and easy to dispose as a buoyancy adjusting liquid, and which is added to its own weight by arranging the bottom tank's own weight, which is insufficient due to thinning, in the bottom cover. It is to provide a construction method capable of constructing a large-scale underground tank simply and economically by supplementing it with a weight.

[0008]

In the following, the construction method of the present invention will be described with reference to the reference symbols in the accompanying drawings. The bottom cover 6 of the tank 1 is floated, the body unit 7 of the underground tank 1 which is divided into a large number is joined to the bottom cover 6, and the buoyancy adjusting liquid 5 is injected to be sunk by a predetermined amount. After the joining and the digging of all the fuselage units 7 are completed, the grout material 9 is filled into the gap between the outer peripheral surface of the underground tank 1 and the hole wall of the digging hole 2 to complete the digging hole. A subterranean tank 1 having a predetermined length is constructed in 2.

In particular, in the construction method of the present invention, water is used as the buoyancy adjusting liquid 5, and the total weight of the weight of the underground tank 1 and the weight of the buoyancy adjusting liquid 5 in the underground tank 1 is When the buoyancy of the underground tank 1 received from the wall protection liquid 3 is insufficient, a weight 8 for adding an own weight for compensating for the deficiency is disposed on the bottom lid portion 6 of the underground tank 1 to provide the fuselage unit 7 Set the joint part of the to a predetermined position on the ground.

[0010]

[Function] While the underground tank 1 becomes thinner, the weight of the underground tank 1 becomes lighter, while the underground tank 1 has a larger diameter, so that the underground tank 1 has a hole wall protection liquid 3 such as bentonite liquid.
The buoyancy received from is increased. Since the buoyancy adjusting liquid 5 injected to reduce the buoyancy and adjust the sinking amount of the underground tank 1 is water and has a lower specific gravity than the hole wall protection liquid 3, the self-weight of the underground tank 1 and the buoyancy The buoyancy is superior to the total weight of the adjustment liquid 5 and the total weight.

Therefore, the necessary weight of the own weight adding weight 8 is calculated so as to make up for the shortage of the total body weight with respect to the buoyancy, and the weight 8 is provided on the bottom cover portion 6 of the underground tank 1. As a result, the joint portion of the uppermost body unit 7 is placed at a predetermined position on the ground. When the bottom cover 6 is completely filled, the weight 8 for adding its own weight is sequentially arranged from below in the required number of body units 7 corresponding to the diameter and length of the underground tank 1.

[0012]

EXAMPLE In the construction procedure of one example of the method of the present invention shown in FIG. 1, first, a hole wall protection liquid 3 such as bentonite liquid was used.
While preventing the collapse of the hole wall, the depth is several hundred meters and the diameter is about 7 ~
An 8 m deep drill hole 2 is drilled in the ground (process a). Next, the bottom lid 6 of the underground tank 1 made of a thin metal having a diameter of 5 to 6 m and a plate thickness of about 10 mm, or the bottom lid 6 to which the lowest body unit 7a is joined in advance. Is floated on the hole wall protection liquid 3 in the excavation hole 2 (process b). Using a concrete pump truck or the like for the floating bottom cover 6, ordinary concrete or heavy concrete using iron ore as coarse aggregate is cast to a predetermined height and hardened, and a weight 8 for adding its own weight is provided. Do (process c).

Subsequently, a predetermined amount of water is injected as the buoyancy adjusting liquid 5 into the underground tank 1 under construction, and the buoyancy by the hole wall protection liquid 3 and the weight of the underground tank 1 and the weight 8 for adding its own weight are added. While balancing and, the fuselage unit 7 is sunk to a predetermined position on the ground where joining work is easy. In the same manner, the underground tank 1 is constructed by repeating joining and sinking of the required number of body units 7 (process d).

These specifications are, for example, when the depth of the underground tank having a depth of 400 m and an inner diameter of 6 m is 9 to 15 mm,
Ultimately, the buoyancy acting on the underground tank is 13,000t
The water as the buoyancy adjusting liquid becomes 11,000t, and the weight for adding the own weight becomes 900t.

After the submersion of the underground tank 1 into the excavation hole 2 is completed, a grout material 9 such as mortar is injected between the underground tank 1 and the excavation hole 2. The filling of the grout material 9 is performed in several stages so that an excessive filling pressure does not act on the underground tank 1 (process e). It should be noted that the weight 8 for adding its own weight is arranged several times each time the number of joining steps of the body unit 7 is added.

Further, the weight 8 for adding own weight is provided by slab having a vertical hole at the center or a thick plate 12 as shown in FIG. It may be arranged by guiding the guide poles 11 installed upright to stack the required number of steps.

FIG. 3 shows an application example of an underground tank constructed by the method of the present invention. In the underground tank 1, hot water 16 is stored by substituting the water of the buoyancy adjusting liquid 5, and the hot water 16 is stored. Is sent to the heat exchanger 14 through the supply pipe 13, the thermal energy is used for cooling and heating.

[0018]

According to the method of the present invention, the internal pressure due to the buoyancy adjusting liquid injected inside the underground tank and the external pressure due to the hole wall protection liquid injected outside the underground tank can be substantially balanced at the time of construction. The thickness of the middle tank can be made very thin, and this thinness can reduce the weight, keep the material cost low, and also reduce the welding time for welding the fuselage, and for handling. The required capacity of heavy equipment can be reduced.

Further, in the method of the present invention, since water is used as the buoyancy adjusting liquid, the buoyancy adjusting liquid can be obtained inexpensively and easily, and when the buoyancy adjusting liquid is replaced with hot water or cold water after the underground tank is completed, a special re-use is required. Since it does not require treatment, it is economically advantageous and there is no problem of environmental pollution.

Furthermore, in the method of the present invention, the total weight of the underground tank and the weight of the buoyancy adjusting liquid is added to compensate for the deficiency in the buoyancy of the underground tank received from the hole wall protection liquid. By disposing the weight on the bottom lid of the underground tank, the joint portion of the fuselage unit can be freely set at a predetermined position on the ground, so that the joint work of the fuselage can be performed reliably and easily.

As a result, according to the method of the present invention, a large-scale underground tank can be constructed easily and economically.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a construction procedure of a thin metal underground tank according to an embodiment of the method of the present invention.

FIG. 2 is a vertical sectional view showing another example of arrangement of weights for adding own weight in the method of the present invention.

FIG. 3 is a vertical sectional view showing an application example in which the completed underground tank is operated as a heat storage tank.

[Explanation of symbols]

 1 Underground tank made of thin metal 2 Drilling hole 3 Protective liquid 4 Groundwater 5 Buoyancy adjusting liquid 6 Bottom lid of underground tank 7 Body unit of underground tank 7a Bottom unit 8 Gravity material for weight addition 9 Grout material 10 Joining surface 11 Guide pole 12 Weight for adding own weight 13 Supply pipe 14 Heat exchanger 16 Hot water

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location E04H 7/18 B 9023-2E (71) Applicant 000006655 Nippon Steel Corporation Chiyoda-ku, Tokyo Town 2-3-6 (72) Inventor Hidehiko Yoshiwaka 5-9-1 Nishihashimoto, Sagamihara-shi, Kanagawa Nippon Steel Corporation Sagamihara Technology Center (72) Inventor Hisashi Hasegawa Otemachi, Chiyoda-ku, Tokyo 2-6-3 Shin Nippon Steel Co., Ltd. (72) Inventor Toshiyuki Hatta 1-2-3 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Nagaaki Kabata Southern distinction of Yokohama City, Kanagawa Prefecture 1-14-1 JGC Corporation

Claims (1)

[Claims] 1. A bottom lid portion 6 of a submerged tank 1 made of a thin metal is floated in a hole wall protection liquid 3 in a deep drilling hole 2 and the bottom lid portion 6 is divided into a large number of subsurface tanks 1. After joining the fuselage units 7 and injecting the buoyancy adjusting liquid 5 and sunk by a predetermined amount, the joining and the depositing of the fuselage units 7 are repeated, and after the joining and the depositing of all the fuselage units 7 are completed, the underground tank 1
A buoyancy adjusting liquid 5 is used in the method of constructing an underground tank, in which a grout material 9 is filled in the gap between the outer peripheral surface of the drill hole and the hole wall of the drill hole 2 to build the underground tank 1 of a predetermined length in the drill hole 2. As the total weight of the ground tank 1 and the buoyancy adjusting liquid 5 in the ground tank 1, the total weight of the hole wall protection liquid 3
If the buoyancy of the underground tank 1 is insufficient,
The weight 8 for adding the own weight to make up for the shortage is provided in the underground tank 1
A method of constructing a thin-walled underground tank made of metal, which is disposed on the bottom cover 6 of the above, and the joint portion of the body unit 7 is set at a predetermined position on the ground.