JP2689860B2 - Roof structure of underground cryogenic liquefied gas tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roof structure for an underground tank which is constructed underground for low temperature liquefied gas such as LNG so as to be able to store a large capacity.

[0002]

2. Description of the Related Art Most of the roof structure of an underground tank of this type is composed of a steel roof like the above-ground tank. On the other hand, in recent years, as the demand for low-temperature liquefied gas tanks has increased, a large-capacity underground storage tank has been required.

Therefore, as countermeasures in Japan where effective use of land is required, conventionally, there are two methods: a method of securing a capacity with a large storage depth and a method of securing a capacity with a large storage diameter. The tank has been constructed by the method.

[0004]

However, among the conventional methods described above, the method of securing the capacity by setting the storage depth to a large depth is used as a still water wall or a retaining wall for deep or deep underground. A continuous wall was required, which was not satisfactory from the viewpoint of construction cost.

On the other hand, in the method of securing the capacity by increasing the storage diameter, it is necessary to make the roof structure a long span (diameter) in order to increase the diameter of the storage tank. Therefore, a large steel material is required for a structure with a long span (diameter), but from the viewpoint of economic efficiency due to the cost increase due to the steel material, the roof diameter of about 60 to 70 m has generally been the limit.

[0006] In the all-concrete roof structure,
Formwork holding supports for concrete placement during construction were required over the entire surface under the roof, which was a problem from the viewpoint of construction labor and cost.

The present invention was devised in view of the above-mentioned circumstances, and an object thereof is to increase the diameter of a tank for increasing the capacity of a storage tank, that is, to increase the roof diameter of the tank to increase the construction cost. It is to provide a roof structure for an underground low temperature liquefied gas tank that can be surely implemented without the need.

[0008]

In the roof structure of the present invention, in order to increase the diameter (increase the diameter) of the storage tank for low temperature liquefied gas, a method for solving the above-mentioned problems such as the construction cost is provided. The structure will have a hybrid type feature that is constructed by combining two types of roof materials.

That is, as shown in FIG. 1, the roof main body, which is the center of the roof of the underground tank, is made of a steel material (roof bone or roof) that maintains the economical span (diameter) conventionally adopted. Plate etc.). At the same time, as a measure for enlarging the inner diameter of the tank, the roof structure at the top of the side wall is formed as an overhanging roof part integrated with the side wall.

In the roof structure of the underground tank according to the present invention having such a structure, the roof materials of the central roof portion and the overhanging roof portion are integrated into a roof structure at the end of construction. By doing so, a large-diameter tank can be formed and a large-capacity storage is possible.

[0011]

The roof structure of an underground low temperature liquefied gas tank according to the present invention will be described below with reference to the illustrated embodiments.

A roof structure 1 (see FIG. 1) of an underground tank 2 for storing low-temperature liquefied gas such as LNG is provided at the top of the side wall 2a of the underground tank 2 so as to be the roof peripheral portion, and from the side wall 2a. An overhanging roof part 3 that is integrally overhanging and exposed on the ground, and a roof frame or roof plate that is provided as much as possible to be the center of the roof in the underground tank 2 and that has a span that is generally adopted. And a roof body 4 made of a steel material. The projecting roof part 3 and the roof body part 4 are configured as an integral dome-shaped roof structure having front and back peripheral surfaces having a constant radius of curvature at the time of completion of construction.

The side wall 2a of the underground tank 2 in this embodiment is made of concrete and is provided on the inner peripheral surface of the continuous wall 6. The sidewall 2a is integrally provided with an overhanging roof portion 3 at its upper end portion, and is provided with a bottom plate 5 of the underground tank 2 at its lower end portion.

When the roof structure 1 having such a structure is adopted and the underground tank 2 is constructed, first, as shown in FIG.
And as shown in FIG. 2, at the tank construction site,
The underground continuous wall 6 is constructed up to the impermeable layer 7 in the ground as a water blocking wall or a retaining wall. Then, after constructing the continuous wall 6, as shown in FIG. 3, a so-called excavator that excavates the internal ground of the continuous wall 6 to a depth that becomes the bottom slab 5 of the underground tank 2 (see FIG. 1). carry out.

Next, after the excavation of the internal ground in the continuous wall 6, the side wall 2a made of concrete and the bottom slab 5 made of concrete which will be the main body of the underground tank 2 are constructed as shown in FIG. Further, when the construction up to the top of the side wall 2a is completed, as shown in FIG. 5, the projecting roof part 3 made of concrete is constructed integrally with the side wall 2a on the top of the side wall 2a.

Next, as shown in FIG. 6, while constructing the overhanging roof portion 3 shown in FIG. 5, the inside of the underground tank 2 is made of steel material (roof bone, roof board, etc.). Assembly of the roof main body 4 to be performed is performed by welding, bolting, or the like. Then, after completing various inspections such as welding inspection, use a jack, winch, etc. to remove the roof body 4 of the steel roof.
Are lifted up to join the overhanging roof portion 3 and joined.

Next, after the roof construction as described above is completed, the inner tank construction such as the cold insulation material mounting construction, the membrane mounting construction, the pipe mounting construction and the like is sequentially performed inside the underground tank 2. In each construction, since the overhanging roof portion 3 and the roof main body portion 4 are formed into an integral dome-shaped roof structure, the inner peripheral surfaces of the overhanging roof portion 3 and the roof main body portion 4 are also It can be carried out in the same manner as the side wall 2a and the bottom slab 5 in the underground tank 2.

After the completion of the inner tank construction, necessary inspections are carried out, and as shown in FIG. 7, the construction of the underground tank 2 which is a large-capacity large-diameter tank is completed.

According to the roof structure 1 of the underground low temperature liquefied gas tank according to the present invention as described above, the roof material of the overhanging roof portion 3 and the roof body portion 4 is integrated into a dome-shaped roof structure at the end of construction. In addition to the above, by adding the overhanging roof part 3 integrated with the side wall 2a to the roof main body part 4 of steel material having a general span (diameter), a large-diameter tank for securing a large capacity becomes possible. ing.

Further, according to the roof structure 1 of the present invention, since the roof main body 4 is an integral dome-shaped roof structure having the same curvature radius as the overhanging roof part 3, bending stress is generated only by the axial compression force. Therefore, it is possible to realize an economical member cross section. Further, since the overhanging roof portion 3 on the top of the side wall 2a is exposed on the ground, it is not affected by the earth pressure, and it is not necessary to take special reinforcement measures.

[0021]

According to the present invention, the roof main body, which is the center of the roof of the underground tank, is made of a steel material (roof bone, roof plate) which has been conventionally used and which maintains an economical span. To do. Moreover, at the same time, as a measure for enlarging the inner diameter of the underground tank, an overhanging roof portion provided integrally with the side wall at the top of the side wall of the tank is added around the roof main body. Then, by forming the roof material of the roof portion of the central portion and the overhanging roof portion as an integral roof structure at the end of construction, it is possible to form an underground tank with a large diameter for the roof body portion, It can enable large-capacity storage.

Further, since the roof main body is an integral dome-shaped roof structure having the same curvature radius as that of the overhanging roof, bending stress is not generated only by the axial compression force, so that an economical member cross section can be realized. Become. Furthermore, since the overhanging roof portion on the top of the side wall is exposed on the ground, it is not affected by earth pressure and it is not necessary to take any special reinforcement measures.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a roof structure of an underground low temperature liquefied gas tank of the present invention.

FIG. 2 is a schematic sectional view showing a construction state of an underground low temperature liquefied gas tank adopting the roof structure of the present invention.

FIG. 3 is a schematic sectional view showing a construction state of an underground low temperature liquefied gas tank adopting the roof structure of the present invention.

FIG. 4 is a schematic sectional view showing a construction state of an underground low temperature liquefied gas tank adopting the roof structure of the present invention.

FIG. 5 is a schematic sectional view showing a construction state of an underground low temperature liquefied gas tank adopting the roof structure of the present invention.

FIG. 6 is a schematic cross-sectional view showing a construction state of an underground low temperature liquefied gas tank adopting the roof structure of the present invention.

FIG. 7 is a schematic sectional view showing a construction state of an underground low temperature liquefied gas tank adopting the roof structure of the present invention.

[Explanation of symbols]

1 ... Roof structure, 2 ... Underground tank, 2a ... Side wall, 3 ... Overhanging roof part, 4 ... Roof body part, 5 ... Bottom plate, 6 ... Continuous wall, 7
… Impermeable layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shinji Nakagawa, former Akasaka 1-2-7, Minato-ku, Tokyo Kashima Construction Co., Ltd. (72) Koichiro Kanai, former Akasaka 1-2-7, Minato-ku, Tokyo Kashima Construction Co., Ltd. (56) Reference JP-A-58-102898 (JP, A)

Claims (1)

(57) [Claims] 1. A roof structure for an underground tank that stores low-temperature liquefied gas such as LNG, which is provided at the top of the side wall of the underground tank so as to form a roof peripheral portion, and extends integrally from the side wall. The overhanging roof exposed on the ground and the central part of the roof of the underground tank are provided as much as possible, and are made of steel materials such as roof bones and roof boards that have a generally adopted span. Consisting of a roof main body that is, the overhanging roof portion and the roof main body portion, at the end of construction,
A roof structure for an underground low temperature liquefied gas tank, characterized in that the front and back surfaces thereof are configured as an integral dome roof-like structure having a constant radius of curvature.