JP2017089163A - Building method of double-shell low-temperature storage tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a building method of a double-shell low-temperature storage tank capable of reducing welding cost in an outer tank AR method and an inner tank AR method, capable of reducing formation-repair cost in a construction port, capable of reducing side plate carrying-in cost, and capable of shortening a construction period.SOLUTION: A building method of a double-shell low-temperature storage tank for constructing a cylindrical inner tank side plate 8 on the inside of a cylindrical outer tank sidewall 3, comprises a side plate block forming process of forming a side plate block 8A, by successively butting and welding the mutual short sides of two side plates 8a one set by one set with the two side plates 8a adjacent in the circumferential direction as the set in an external part of the outer tank sidewall 3, a side plate block construction process of constructing the side plate block 8A along the outer tank sidewall 3 so that a welding line 8u formed by the side plate block forming process becomes the vertical direction by carrying in the side plate block 8A in the next place to the inside of the outer tank sidewall 3 from a construction port formed on the outer tank sidewall 3 and a side plate block welding process of welding the mutual side plate blocks 8A adjacent in the circumferential direction and the mutual side plate blocks 8A adjacent in the vertical direction to the inside of the outer tank sidewall 3 in the next place.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for constructing a double shell cryogenic storage tank, and more particularly to an improved construction method for an inner tank side plate.

  The double-shell low-temperature storage tank that stores LNG (liquefied natural gas), etc. is an outer tank side wall composed of a cylinder made of PC (prestressed concrete) and a steel plate liner attached to the inner surface thereof, and a cylindrical type made of low-temperature steel plate The inner tank side plate, the concrete base plate and the outer tank bottom plate laid on the concrete base plate, the inner tank bottom plate made of low temperature steel plate laid on the upper surface of the cold insulation material on the outer tank bottom plate, and the low temperature steel plate made of It is composed of a roof structure consisting of an inner tank roof and an ordinary tank outer tank roof, etc., and other related equipment in the double shell low temperature storage tank (cooling material such as pearlite filling between the outer tank and the inner tank) Included) and equipment.

  As a method for constructing the double-shell low-temperature storage tank, an outer tank AR method (outer tank air-raising method) and an inner tank AR method (inner tank air-raising method) are widely used.

  In the outer tank AR method, a roof structure (but in an unfinished state) is manufactured inside the outer tank side wall while the outer tank side wall is being constructed, and the outer tank side wall and the outer tank roof are sealed with a sealing member and pressurized. Air lasing is performed by injecting air to raise the roof structure with air pressure, and then the outer tank roof is connected to the outer tank side wall.

Next, wind and rain are prevented by the above-mentioned roof structure, and the inner tank bottom plate is laid and the inner tank side plate is constructed inside the outer tank side wall while heating the inside of the outer tank side wall during cold weather.
The inner tank side plate is, for example, a curved rectangular side plate (for example, the largest side plate has a size of 4 m × 10 m, a plate thickness, for example, 50 to 10 mm) formed in the outer tank side wall one by one in the outer tank side wall. Carry in, arrange multiple side plates in the circumferential direction and multiple stages in the height direction, and build them by welding the longitudinal weld seam and the lateral weld seam (circumferential weld seam) between the side plates .

In the inner tank AR method, the outer tank side wall, the inner tank side plate, the inner tank bottom plate, and the roof structure (but not completed) are constructed in parallel, and then the inner tank side plate and the inner tank roof are sealed with a sealing member. Then, air lasing for injecting pressurized air to raise the roof structure with air pressure is performed, and then the inner tank roof is joined to the inner tank side plate via the knuckle plate.
When constructing the inner tank side plate, the side plates of the inner tank side plate are carried one by one from the upper side of the outer tank side wall into the outer tank side wall using a crane, and a plurality of the side plates are arranged in the circumferential direction and in the height direction. An inner tank side plate is constructed by arranging a plurality of stages and welding them to the longitudinal weld seam and the lateral weld seam between the side plates.
In this inner tank AR method, since the outer tank side wall, the inner tank side plate, the inner tank bottom plate, and the roof structure are constructed in parallel, there is an advantage that the construction period can be shortened.

The construction method of the cylindrical tank (double-shell cryogenic storage tank) described in Patent Document 1 is such that when the tank is constructed by the outer tank AR method, outside the side wall of the outer tank, in the vertical direction among the side plates of the inner tank side plate. Two adjacent side plates were used as a set to produce a side plate block in which the long sides of the two side plates were abutted and welded sequentially, and this side plate block was placed on the carriage and formed on the outer tank side wall. It carries in into an outer tank side wall from a large-sized construction port (for example, 8 m or more of vertical widths), and a side plate block is constructed along the outer tank side wall so that the welding line becomes a horizontal direction.

Japanese Patent No. 5672787

  In the construction method of the cylindrical tank described in Patent Document 1, in order to carry a side plate block in which two side plates are arranged side by side in the vertical direction into the outer tank side wall, a particularly large construction port is formed on the outer tank side wall. There must be. Thus, in addition to being a weak point in the strength of the PC outer tank side wall (liquid breakwater), it takes a lot of cost to form and repair the construction opening.

  On the other hand, when constructing the inner tank side plate of the double shell cryogenic storage tank by the conventional inner tank AR method, the side plates were carried one by one from the upper side of the outer tank side wall into the outer tank side wall using a crane. It was not possible to shorten the construction period and reduce the welding cost.

  The purpose of the present invention is to reduce the cost of forming and repairing construction openings when constructing a double-shell cryogenic storage tank using the outer tank AR method, and the construction period when constructing a double-shell cryogenic storage tank using the inner tank AR method The aim is to shorten the welding cost.

  In the construction method of the double-shell cryogenic storage tank according to claim 1, a plurality of curved rectangular side plates are arranged in the circumferential direction and arranged in a plurality of stages in the height direction inside the cylindrical outer tank side wall. In the construction method of the double-shell low-temperature storage tank in which a cylindrical inner tank side plate is constructed by welding the plurality of side plates, two side plates adjacent in the circumferential direction outside the outer tank side wall are grouped as 1 The side plate block forming step of forming a side plate block by welding the short sides of the two side plates in contact with each other in sequence, and then from the construction port formed on the side wall of the outer plate to the outer vessel side wall The side plate block construction step of constructing the side plate block along the outer tank side wall so that the weld line formed in the side plate block forming step is in the vertical direction, and then the outer tank side wall Inside, adjacent in the circumferential direction Is characterized in that a side plate block welding step of welding the side plate blocks adjacent to each other in the plate between blocks and the vertical direction.

  The construction method of the double shell cryogenic storage tank according to claim 2 is the invention according to claim 1, wherein in the side plate block construction step, the side plate block is constructed so that the plate thickness of the side plate gradually decreases upward. The side plate block is constructed such that the inner surface of the inner tank side plate is a cylindrical surface without a step.

  The construction method of the double-shell cryogenic storage tank according to claim 3 includes arranging a plurality of curved rectangular side plates in the circumferential direction and a plurality of steps in the height direction inside the cylindrical outer tank side wall. In the construction method of the double-shell cylindrical tank that constructs the cylindrical inner tank side plate by welding the plurality of side plates, in the outside of the outer tank side wall, as a set of two side plates adjacent in the vertical direction, The side plate block forming step of forming a side plate block by welding the long sides of the two side plates abutting each other in sequence, and then removing the side plate block from above the side wall of the outer tank using a crane A side plate block construction step for carrying in the inside of the tank side wall and constructing the side plate block along the outer tank side wall so that the weld line formed in the side plate block forming step is in a horizontal direction; Around the inside of the side wall Is characterized in that a side plate block welding step of welding the side plate blocks adjacent to each other in the side plates between blocks and vertically adjacent.

  The construction method of the double shell cryogenic storage tank according to claim 4 is the invention according to claim 3, wherein in the side plate block forming step, the side plates having different thicknesses are aligned with each other so that the inner side plate surfaces of the inner tank side plates are aligned. The side plate block is formed by welding, and in the side plate block construction step, the side plate block is constructed such that the inner surface of the inner tank side plate is a cylindrical surface without a step.

  The construction method of the double-shell cryogenic storage tank according to claim 5 is the invention according to any one of claims 1 to 4, wherein the outer tank side wall has a prestressed concrete breakwater. Yes.

Since the invention of the present application has the configuration described in the column of problem solving means, the following effects are obtained.
According to the first aspect of the invention, outside the outer tank side wall, the two side plates adjacent in the circumferential direction are welded to form the side plate block, so that the work is formed on the outer tank side wall to carry in the side plate block. Since it is not necessary to form the upper and lower widths of the mouth to be particularly large, the cost for forming and repairing the construction mouth can be reduced.
And, compared with the case where the side plate is carried into the outer tank side wall one by one and the inner tank side plate is constructed, the total length of the longitudinal weld seam when constructing the inner tank side plate can be halved, so the construction period can be shortened and welding Cost can be reduced.

  According to invention of Claim 2, in order to construct a side plate block so that the plate | board thickness of a side plate may become small gradually toward upper direction, the side plate of the plate | board thickness according to the hydraulic pressure of the low temperature liquefied gas which acts on an inner tank side plate, Therefore, the structure of the inner tank side plate can be made lean. Since the inner surface of the inner tank side plate is a cylindrical surface without a step, it is advantageous in calculating the storage amount from the liquid level of the low-temperature liquefied gas.

  According to the invention of claim 3, the side plates of the two side plates are butted against each other on the outside of the outer tank side wall to form a side plate block, and the side plate block is located above the outer tank side wall using a crane. Since it carries in to an outer tank side wall and uses for construction | assembly of an inner tank side board, since the total length of the horizontal direction welding seam at the time of inner tank side board construction can be halved, welding cost can be reduced significantly. Moreover, since the total number of times the side plate is carried into the outer tank side wall from above the outer tank side wall by the crane can be halved, the construction period can be shortened, and the side plate carrying cost can be greatly reduced. It is not necessary to form a large construction port on the outer tank side wall for carrying in the side wall block. As a result, the construction cost can be significantly reduced and the construction period can be shortened.

According to the invention of claim 4, the same effect as that of claim 2 can be obtained, and the inner surface of the inner tank side plate is formed into a cylindrical surface without a step. It becomes possible to raise.
According to the invention of claim 5, it is possible to construct an outer tub side wall having high strength and durability.

It is a longitudinal cross-sectional view of the right half of the double shell cryogenic storage tank which concerns on Example 1 of this invention. It is a partial longitudinal cross-sectional view of the annular plate of the inner tank bottom plate and the inner tank side plate. It is sectional drawing which shows the state which air-raises a roof structure by the outer tank AR method. It is sectional drawing which shows the state which builds the lower step part of an inner tank side plate. It is sectional drawing which shows the state which builds the middle step part of an inner tank side plate. It is sectional drawing which shows the state which builds the upper stage part of an inner tank side plate. It is sectional drawing which shows the state which builds the lower step part of an inner tank side plate, etc. in the case of construction of the double shell low temperature storage tank which concerns on Example 2. FIG. It is sectional drawing which shows the state which builds the lower step part of an inner tank side plate, an inner tank roof, etc. It is sectional drawing which shows the state which builds the middle step part of an inner tank side plate, an outer tank roof, etc. FIG. It is sectional drawing which shows the state which builds the upper stage part etc. of an inner tank side plate. It is sectional drawing which shows the state which air-raises a roof structure by the inner tank AR method.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

  As shown in FIG. 1, this double shell cryogenic storage tank 1 stores LNG (liquefied natural gas), and this double shell cryogenic storage tank 1 is constructed on a number of foundation piles (not shown). Reinforced concrete foundation plate 2, prestressed concrete (PC) cylindrical outer tank side wall 3 (breakwater) rising from the outer periphery of this foundation plate 2, and laid on the upper surface of the foundation plate 2 A bottom liner 4 (outer tank bottom plate), a side liner 5 raised from the outer peripheral end of the bottom liner 4 and attached to the inner peripheral surface of the outer tank side wall 3 and belonging to the outer tank side wall; An inner tank bottom plate 7 installed on the upper surface via a cold insulating material 6 having a predetermined thickness, and an inner tank bottom plate 7 which is an outer peripheral side portion of this inner tank bottom plate 7 is raised from the vicinity of the outer peripheral end and side portions It is arranged at a predetermined distance from the liner 5 Cylindrical inner tank side plate 8, a thermal resistance relaxation material (for example, polyurethane foam) having a predetermined thickness formed on the inner surface of side liner 5, and a gap between side liner 5 and inner tank side plate 8 And a roof structure 13 incorporating a cold insulation material 12 between the inner tank roof 10 and the outer tank roof 11.

The bottom liner 4, the side liner 5, the outer tank roof 11, and the like are made of ordinary steel. The inner tank bottom plate 4, the inner tank side plate 8, the inner tank roof 10 and the like are made of low temperature steel.
The inner tank side plate 8 includes a plurality of curved rectangular side plates 8a arranged in the circumferential direction inside the outer tank side wall 3 and a plurality of steps arranged in the height direction, and the plurality of side plates 8a are welded. It is constructed as a cylindrical inner tank side plate 8.

  As shown in FIG. 2, in the inner tank side plate 8, the inner tank side plate 8 is constructed using a side plate block 8 </ b> A described later so that the plate thickness of the side plate 8 a gradually decreases upward. The side plate block 8A is constructed so that the inner surface is a cylindrical surface without a step.

Next, among the methods for constructing the double-shell low-temperature storage tank 1 by the outer tank AR method, the construction method of the inner tank side plate related to the present invention will be described with reference to FIGS.
FIG. 3 shows the foundation pile, the foundation slab 2, the bottom liner 4 on the foundation slab 2, the PC outer tank side wall 3 (liquid barrier), and the roof structure 13, and then the outer tank side wall 3 A state in which the roof structure 13 is air-raised by sealing between the outer tank roof 11 with a sealing member and supplying pressurized air to the space inside the outer tank side wall 3 and below the roof structure 13 by the blower 15. Is shown.

  After the outer tank air lasing, the outer tank roof 11 is connected and fixed to the upper end of the outer tank side wall 3, and the knuckle plate 10a on the outer periphery of the lower end of the inner tank roof 10 is raised to a predetermined height and held in a suspended state. .

4 shows a state in which the lower part of the inner tank side plate 8 is constructed, FIG. 5 shows a state in which the middle part of the inner tank side plate 8 is constructed, and FIG. 6 shows a state in which the upper part of the inner tank side plate 8 is constructed. Show.
The plurality of side plates 8a forming the inner tank side plate 8 are constructed as the inner tank side plate 8 through the following side plate block forming step, side plate block construction step, and side plate block welding step.

  In the side plate block forming step, two side plates 8a adjacent to each other in the circumferential direction are paired outside the outer tank side wall 3, and the short sides of the two side plates 8a are sequentially butted against each other and welded. The side plate block 8A is formed.

  Next, in the side plate block construction process, the side plate block 8A is carried into the outer tank side wall 3 from the construction port 3a formed on the outer tank side wall 3 in a state where the side plate block 8A is placed on the carriage 17 via the crane 16 to form the side plate block. The side plate block 8A is constructed along the outer tank side wall 3 so that the weld line 8u (longitudinal weld seam) formed in the process is in the vertical direction.

  In this side plate block construction process, as shown in FIG. 2, the side plate block 8A is constructed so that the plate thickness of the side plate 8a decreases sequentially upward, and the inner surface of the inner tank side plate 8 The inner plate side plate 8 is constructed by constructing the side plate block 8A.

  Next, in the side plate block welding step, the weld seam between the side plate blocks 8A adjacent in the circumferential direction and the weld seam between the side plate blocks 8A adjacent in the vertical direction are welded inside the outer tank side wall 3.

  Here, the other construction work performed in parallel with the construction of the inner tank side plate 8 will be supplementarily described. In FIG. 4, the side liner 5 is attached to the inner surface of the outer tank side wall 3. In FIG. 5, the cold insulating material 6 is laid on the bottom liner 4. In FIG. 6, the inner tank bottom plate 7 is installed and welded, the inner tank roof 10 and the knuckle plate 10 a are lowered by a predetermined height, and the lower end portion of the knuckle plate 10 a is welded and joined to the upper end of the inner tank side plate 8.

Next, the operation and effect of the construction method of the double shell cryogenic storage tank of the present invention will be described.
Outside the outer tank side wall 3, two side plates 8 a adjacent in the circumferential direction are welded to form the side plate block 8 A, so that the upper and lower sides of the construction port 3 a formed in the outer tank side wall 3 to carry in the side plate block 8 A Since it is not necessary to form a particularly large width, it is possible to reduce the formation and repair costs of the construction port 3a.

  And compared with the case where the side plate 8a is carried into the outer tank side wall 3 one by one and the inner tank side plate 8 is constructed, the total length of the longitudinal weld seam when the inner tank side plate 8 is constructed can be reduced by half. Can be reduced. In particular, since the welding speed of the longitudinal weld seam is slower than that of the transverse weld seam, the welding cost can be significantly reduced. As a result, the construction period can be shortened.

  Since the side plate block 8A is constructed so that the plate thickness of the side plate 8a gradually decreases upward, the side plate 8a having a plate thickness corresponding to the hydraulic pressure of the low-temperature liquefied gas acting on the inner tank side plate 8 can be obtained. The structure of the inner tank side plate 8 can be made lean. Since the inner surface of the inner tank side plate 8 has a cylindrical surface without a step, it is advantageous in calculating the storage amount from the liquid level of the low-temperature liquefied gas.

  The second embodiment relates to a method for constructing a double-shell low-temperature storage tank having the same structure as the double-shell low-temperature storage tank 1 of the first embodiment by the inner tank AR method. Hereinafter, the construction method of the inner tank side plate related to the present invention among the above construction methods will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected and demonstrated to the same member as Example 1. FIG.

FIG. 7 shows a state in which the foundation pile, the foundation slab, the bottom structure 2A including the bottom liner 4 on the foundation slab, and the lower step of the PC outer tank side wall 3 (liquid barrier) are already constructed. .
In the step shown in FIG. 7, the roof mount 20a (center part) is further assembled, the annular plate 7a of the inner tank bottom plate 7 is installed in an annular shape and welded, the middle step of the outer tank side wall 3 is constructed, and the inner tank side plate 8 is constructed, and the roof mounts 20b and 20c (outer peripheral part and intermediate part) are assembled.

  Next, in the process shown in FIG. 8, the lower and middle steps of the inner tank side plate 8 are constructed, the upper stage of the outer tank side wall 3 is built, the inner tank roof 10 is manufactured on the gantry, and the outer tank side wall 3. The top liner 5a of the side liner 5 on the inner surface of the outer tank side wall 3 is constructed.

  Next, in the step shown in FIG. 9, the cold insulation material 6 is laid on the upper surface of the bottom liner 4, the middle stage portion of the inner tank side plate 8 is constructed, and the roof mounts 20 a to 20 c (center portion, intermediate portion) are disassembled, The outer tank roof 11 is manufactured on the upper side of the inner tank roof 10.

  Next, in the process shown in FIG. 10, the remaining part of the outer tank roof 11 is manufactured, the remaining part of the side liner 5 is assembled and welded to the inner surface of the outer tank side wall 3, and the upper part of the inner tank side plate 8 is constructed. The knuckle plate 8k is assembled and welded to the upper end portion of the inner tank side plate 8, and the inner tank bottom plate 7 is installed and welded to the upper surface of the cold insulating material 6.

  Next, in the step shown in FIG. 11, in order to perform the inner tank AR, an air lathing seal member 22 is attached to the outer peripheral edge of the inner tank roof 10 to prepare a plurality of blowers 22, and the inner tank AR method is used. Air lasing for raising the roof structure 13A composed of the tank roof 10 and the outer tank roof 11 is performed, and then the inner tank roof 10 is temporarily fixed, and the outer peripheral portion 20c of the roof frame and the air lathing equipment are removed.

  Next, in the process after FIG. 11, the inner tank roof 10 and the knuckle plate 8k are welded, the outer peripheral part of the outer tank roof 11 is manufactured, and other various incidental constructions are performed.

  In the process shown in FIGS. 7 to 10, when the inner tank side plate 8 is constructed, the plurality of side plates 8 a forming the inner tank side plate 8 include the following side plate block forming process, side plate block building process, and side plate block. The inner tank side plate 8 is constructed through a welding process.

  In the side plate block forming step, two side plates 8a adjacent in the vertical direction are set outside the outer tank side wall 3 as a set, and the long sides of the two side plates 8a are sequentially butted and welded. The side plate block 8B is formed. In this side plate block forming step, the side plates 8a having different thicknesses are welded so that the plate surfaces on the inner surface side of the inner tank side plate 8 are aligned to form the side plate block 8B.

  Next, in the side plate block construction process, the side plate block 8B is carried into the outer tank side wall 3 from above the outer tank side wall 3 using the crane 16, and the welding line 8w formed in the side plate block forming process is set in the horizontal direction. The side plate block 8B is constructed along the outer tank side wall 3 so as to be. In this side plate block construction step, the side plate block 8B is constructed so that the inner surface of the inner tank side plate 8 is a cylindrical surface without a step.

  Next, in the side plate block welding step, the weld seam between the side plate blocks 8B adjacent in the circumferential direction and the weld seam between the side plate blocks 8B adjacent in the vertical direction are welded inside the outer tank side wall 3.

Next, the operation and effect of the construction method of the above-mentioned double shell low temperature storage tank will be described.
The side plates 8B are formed by abutting and welding the long sides of the two side plates 8a outside the outer tank side wall 3, and the side plate block 8B is connected to the outer tank from above the outer tank side wall 3 using the crane 16. Since it carries in in the side wall 3 and uses for construction | assembly of the inner tank side board 8, the total length of the horizontal direction welding seam at the time of inner tank side board 8 construction can be halved, Therefore A welding cost can be reduced significantly. Moreover, since the total number of times the side plate is carried into the outer tub side wall 3 from above the outer tub side wall 3 by the crane 16 can be halved, the carrying-in cost of the side plate 8a can be greatly reduced. Moreover, it is not necessary to form a large construction port for carrying in the side plate block 8B in the outer tank side wall 3. As a result, the construction cost can be significantly reduced and the construction period can be shortened.

  In the side plate block forming step, the side plates 8a having different thicknesses are welded so that the plate surfaces on the inner surface side of the inner tank side plate 8 are aligned to form the side plate block 8B, and in the side plate block construction step, the inner tank side plate 8 The side plate block 8B is constructed so that the inner surface of the inner tank becomes a cylindrical surface without a step, and the inner surface of the inner tank side plate 8 is formed into a cylindrical surface without a step, so that the roof structure is smoothly and reliably air-raised by the inner tank AR method. This is advantageous in calculating the storage amount from the liquid level of the low-temperature liquefied gas.

  Since the outer tank side wall 3 has a liquid barrier made of prestressed concrete, an outer tank side wall with high strength and durability can be constructed.

Next, an example in which the above embodiment is partially changed will be described.
1) The size and capacity of the double shell cryogenic storage tank are not limited in any way, and the present invention can be applied to the construction of double shell cryogenic storage tanks of various sizes and capacities.

2) In the above embodiment, the double shell cryogenic storage tank for storing LNG has been described as an example. However, the present invention is not limited to LNG but is applied to the construction of a double shell cryogenic storage tank for storing various cryogenic liquids. Can do.
3) In addition, those skilled in the art can implement the present invention by adding various modifications to the above embodiments without departing from the spirit of the present invention, and the present invention includes such modifications. It is.

DESCRIPTION OF SYMBOLS 1 Double-shell low temperature storage tank 3 Outer tank side wall 3a Construction port 8 Inner tank side plate 8a Side plate 8A, 8B Side plate block 8u, 8w Welding line 16 Crane

Claims (5)

A plurality of curved rectangular side plates are arranged in the circumferential direction inside the cylindrical outer tub side wall, and a plurality of steps are arranged in the height direction, and the plurality of side plates are welded to form a cylindrical inner tub side plate. In the construction method of the double shell cryogenic storage tank to be built,
Forming two side plates adjacent to each other in the circumferential direction outside the side wall of the outer tub side by side, forming a side plate block by welding the short sides of the two side plates in contact with each other. Process,
Next, the side plate block is carried into the outer tub side wall from the construction port formed on the outer tub side wall, and the side plate block is placed in the outer tub so that the welding line formed in the side plate block forming step is in the vertical direction. Side plate block construction process to construct along the side wall;
Next, in the outer tank side wall, a side plate block welding step of welding side plate blocks adjacent in the circumferential direction and side plate blocks adjacent in the vertical direction;
A method of constructing a double-shell cryogenic storage tank characterized by comprising:   In the side plate block construction step, the side plate block is constructed so that the plate thickness of the side plate gradually decreases upward, and the side plate block is constructed so that the inner surface of the inner tank side plate is a cylindrical surface without a step. The construction method of the double shell cryogenic storage tank according to claim 1, wherein A plurality of curved rectangular side plates are arranged in the circumferential direction inside the cylindrical outer tub side wall, and a plurality of steps are arranged in the height direction, and the plurality of side plates are welded to form a cylindrical inner tub side plate. In the construction method of the double-shell cylindrical tank to be constructed,
Outside the outer tub side wall, a side plate block is formed by forming two side plates adjacent to each other in the vertical direction as a set and sequentially welding the long sides of the two side plates together to form a side plate block. Process,
Next, the side plate block is carried into the outer tank side wall from above the outer tank side wall using a crane, and the side plate block is removed from the outer tank so that the weld line formed in the side plate block forming step is in the horizontal direction. Side plate block construction process constructed along the tank side wall,
Next, in the outer tank side wall, a side plate block welding step of welding side plate blocks adjacent in the circumferential direction and side plate blocks adjacent in the vertical direction;
A method of constructing a double-shell cryogenic storage tank characterized by comprising: In the side plate block forming step, side plates having different thicknesses are welded so that the plate surfaces on the inner surface side of the inner tank side plate are aligned, and the side plate block is formed.
4. The construction of a double-shell low-temperature storage tank according to claim 3, wherein in the side plate block construction step, the side plate block is constructed so that the inner surface of the inner tank side plate is a cylindrical surface without a step. Method.   The method for constructing a double-shell low-temperature storage tank according to any one of claims 1 to 4, wherein the outer tank side wall has a liquid barrier made of prestressed concrete.