JP2745097B2 - Construction method of low temperature liquefied gas underground 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 method for constructing a low-temperature liquefied gas underground tank such as LNG.

[0002]

2. Description of the Related Art As a method for constructing a large-capacity low-temperature liquefied gas underground tank, such as LNG, on a coast or the like, the following method has conventionally been adopted.

[0003] One of them is to construct a water blocking wall or a retaining wall in a landfill at a seaside area, excavate the inside thereof, construct a concrete frame from a bottom portion and a lower end of a side wall, and then construct a roof and a cold insulator, a membrane, or the like. It is a method of performing inner tank construction.

Another method is to construct a water blocking wall or earth retaining wall in a landfill area at the seaside, and then excavate the water stopping wall or earth retaining wall as a structural reaction force to sequentially reverse the concrete frame from the top. Construction method, then the bottom concrete,
This is a method of constructing roof and inner tank construction.

[0005] Still another is that after constructing a water blocking wall or a retaining wall in a landfill in a seaside area, constructing a side wall concrete, laying it down with an open caisson, and then constructing a bottom concrete, a roof and an inner tank. How to build.

[0006]

In each of these conventional construction methods, various processes (water stop wall or retaining wall and side wall concrete frame, side wall concrete and bottom slab concrete, bottom slab concrete and roof, roof and inner slab) are required in the construction. Tanks, etc.) can hardly be constructed at the same time, and the construction period becomes extremely long. By the way, a large underground tank of more than 130,000 KL took more than 42 months to complete.

[0007] The object of the present invention is to solve the disadvantages of the conventional example, and to construct a large-capacity underground tank in a coastal area or the like.
Rational construction is performed step by step, and construction work at the construction point can be omitted as much as possible, and construction efficiency at this construction point can be improved. An object of the present invention is to provide a method for constructing a liquefied gas underground tank.

[0008]

SUMMARY OF THE INVENTION In order to attain the above object, the present invention provides a bottom plate and a part of a side wall which are to be a part of a body of an underground tank at a dock or the like on the ground to obtain sufficient buoyancy at the dock or the like. The bottom plate and a part of the side wall are formed with a hollow part into which ballast water and the like can be injected, and a part of this frame is pulled out from the dock etc. After completing part or all of the remaining side walls and roof construction, inner tank construction, etc., and also forming a hollow part capable of injecting ballast water etc. into these remaining side walls to complete the body of the underground tank, Improvement, construction of revetment, towing the body of the underground tank at sea to the tank construction point where work such as sea leveling has been completed, inject ballast water etc. into the hollow part at this tank construction point, Its weight After landing at, close the provisional deadline of the revetment, remove seawater inside the deadline, discharge ballast water etc., place concrete in necessary filling parts, backfill around tanks, etc. Is what you do.

[0009]

According to the present invention, an acceptable size for obtaining sufficient buoyancy such that a tank body floats from the bottom of a dock or the like when the seawater is immersed in the dock or the like having a shallow bottom. Part of the structure of the underground tank will be built up to the bottom plate and part of the side wall. Then, the body of the underground tank when pulled out from the dock or the like can secure a sufficient volume for obtaining buoyancy because not only the bottom plate but also a part of the side wall is constructed. In addition, since the underground tank is partially constructed, it is lightweight and easy to pull out. The hollow portion formed in the bottom plate and a part of the side wall contributes to the weight reduction of the frame.

The skeleton pulled out of the dock or the like in this manner is used to complete the skeleton of the underground tank by, for example, performing some or all of the remaining side walls, roof work, inner tank work, etc. on the sea near the dock or the like. However, in this case, the body of the underground tank sinks deeper into the sea than at the time of drawer, but since the depth from the sea surface to the sea floor is considerable, it may be impossible to tow due to climbing to the bottom. Absent. The construction of the remaining part of the side wall, roof construction and interior work will increase the weight, but the remaining part of the side wall will secure a sufficient volume in the underground tank body and provide sufficient buoyancy. .

In addition, since the body of the underground tank is completed on the offshore such as a dock, when towing offshore, even if it rains, water is collected in the underground tank because of the roof. There is no danger and the side wall is high, so it can cope with high waves.

[0012] Then, at the construction site, the landing can be easily increased by injecting ballast water or the like into the hollow portion. Since it has already been completed by performing part or all of the construction and inner tank construction, it is heavy and easy to settle. As described above, it is only necessary to land the skeleton of the almost completed underground tank at the tank construction site, and the type of construction work at the construction site can be omitted as much as possible.

In addition, at the time of construction at this construction site, since a deadline is set and seawater inside the deadline is eliminated, ballast water is discharged and concrete is poured into the hollow portion, so that these operations are easy to perform. In general, the structure of the underground tank is rationally constructed step by step, and the construction period at the conventional construction site can be reduced by about 50%.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 6 are longitudinal side views of respective steps showing one embodiment of the method for constructing a low-temperature liquefied gas underground tank of the present invention, FIGS. 7 to 10 are plan views of the respective steps, and FIG. FIG. 12 is a vertical sectional side view of the underground tank, and FIG.

As shown in FIG. 1 and FIG.
The bottom slab 3 and a part of the side wall 4 which become a part of the concrete body of the underground tank 2 are constructed by the above method. Such a frame of the bottom plate 3 and the underground tank 2 which is a part of the side wall 4 is constructed to an allowable size for obtaining sufficient buoyancy in the dock 1 or the like. The gate or temporary deadline 5 is the gate or temporary deadline for the dock 1.

A hollow portion 6 into which ballast water or the like can be injected is formed in the bottom plate 3 and a part of the side wall 4. At the time of constructing the hollow part 6, when constructing the concrete of the part of the side wall and the bottom part, reinforcing work such as a reinforcing bar for making the part of the hollow part 6 the main body concrete (post-casting) is performed at the same time.

In addition, for the reinforcing bars and the like, a material having anticorrosion measures selected so as not to corrode when ballast water or the like is injected by seawater later, or other anticorrosion measures are taken.

Next, as shown in FIG.
Is pulled out from the dock 1 or the like, and as shown in FIG. 2, a part or all of the construction of the remaining side wall 4 and the roof 7 and the inner tank construction are carried out on the sea near the dock 1 and the like. On this occasion,
A hollow portion 6 into which ballast water or the like can be injected is formed also on the remaining side wall 4.

On the other hand, as shown in FIG. 3, apart from the construction of the skeleton at the dock 1 or the like, at the same time or in advance, at the tank construction point 8, the ground improvement, seawall construction, sea leveling, etc. Perform construction.

The main body of the built underground tank 2 shown in FIG. 2 is towed on the sea to a construction point 8 of the tank as shown in FIG. The method of towing the main body of the underground tank 2 at sea may be either a method of directly floating the tank main body or a method of directly mounting the tank main body on the barge from the dock 1 or the like.

At the tank construction point 8, as shown in FIG. 4, ballast water such as seawater is injected into the hollow portion 6 inside the body of the underground tank 2, and the underground tank 2 is settled on the seabed by its weight.

Next, the seawall between the inside of the seawall and the body of the underground tank 2 is removed by a pump after closing the seawall cutoff 9, and the ballast water in the hollow portion 6 is similarly discharged by the pump. Cast concrete into 6 and fill it.

The inner tank construction such as heat insulation and membrane inside the underground tank 2 is performed.

Further, as shown in FIGS. 6 and 10, the gap around the drained tank is back-filled with good quality soil such as sand, and all the construction is completed.

Although not shown in the drawings as another embodiment, the bottom of the main body of the underground tank 2 is not only filled with ballast water or the like using the hollow portion 6 but also directly into the underground tank 2 with seawater or the like. May be injected by a required weight.

In addition to the method of installing a tank on a part of the revetment as in the above embodiment, as shown in FIGS. 13 and 14, the main body of the underground tank 2 is towed to a point on the ocean so as to become an artificial island 10, After landing, close around the tank and reclaim it.
It is also possible to build artificial islands offshore with NG tanks.

[0027]

As described above, the method for constructing a low-temperature liquefied gas underground tank according to the present invention enables rational construction step by step even in the construction of a large-capacity underground tank at a shore or the like. As long as the type of construction work at the construction site can be omitted, construction efficiency at the construction site can be improved, and construction can be generally performed in a shorter time than before.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a first step showing one embodiment of a method for constructing a low-temperature liquefied gas underground tank of the present invention.

FIG. 2 is a vertical sectional side view of a second and third steps showing one embodiment of the method for constructing a low-temperature liquefied gas underground tank of the present invention.

FIG. 3 is a vertical sectional side view of a tank construction point showing one embodiment of the method for constructing a low-temperature liquefied gas underground tank of the present invention.

FIG. 4 is a vertical sectional side view of a fourth step showing one embodiment of the method for constructing a low-temperature liquefied gas underground tank according to the present invention.

FIG. 5 is a vertical sectional side view of a fifth step showing one embodiment of the method for constructing a low-temperature liquefied gas underground tank of the present invention.

FIG. 6 is a vertical sectional side view of a sixth step showing one embodiment of the method for constructing a low-temperature liquefied gas underground tank of the present invention.

FIG. 7 is a plan view of a first step showing one embodiment of the method for constructing a low-temperature liquefied gas underground tank according to the present invention.

FIG. 8 is a plan view of a second step showing one embodiment of the method for constructing a low-temperature liquefied gas underground tank of the present invention.

FIG. 9 is a plan view of a third step showing one embodiment of the method for constructing a low-temperature liquefied gas underground tank of the present invention.

FIG. 10 is a plan view of a sixth step showing one embodiment of the method for constructing a low-temperature liquefied gas underground tank of the present invention.

FIG. 11 is a vertical sectional side view of a low-temperature liquefied gas underground tank constructed by the construction method of the present invention.

FIG. 12 is a partially cutaway plan view of a low-temperature liquefied gas underground tank constructed by the construction method of the present invention.

FIG. 13 is a one-step plan view showing another embodiment of the method for constructing a low-temperature liquefied gas underground tank according to the present invention.

FIG. 14 is a plan view of another process showing another embodiment of the method for constructing a low-temperature liquefied gas underground tank of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Dock 2 ... Underground tank 3 ... Bottom plate 4 ... Side wall 5 ... Gate or temporary deadline 6 ... Hollow part 7 ... Roof 8 ... Construction point 9 ... Deadline 10 ... Artificial island

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Koichiro Kanai 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. (56) References JP-A-57-172076 (JP, A) JP-A Sho 55-132869 (JP, A) JP-A-51-38202 (JP, A)

Claims (1)

(57) [Claims] 1. A bottom plate and a part of a side wall which are to be a part of a body of an underground tank in a dock or the like on the ground are constructed to an allowable size for obtaining sufficient buoyancy in the dock or the like, and the bottom plate and Part of the side wall has a hollow part into which ballast water etc. can be injected, and a part of this frame is pulled out from the dock, etc., and the remaining side wall and part of the roof construction, inner tank construction, etc. on the sea near the dock etc. Or, after constructing all, forming a hollow part that can inject ballast water etc. into the remaining side walls and completing the underground tank body, work in advance on ground improvement, construction of seawalls, leveling of the sea bottom, etc. After towing the body of the underground tank at sea to the tank construction point that has been completed, inject ballast water etc. into the hollow part at this tank construction point, settle down with its weight, and then temporarily close the seawall Close, within deadline A method for constructing a low-temperature liquefied gas underground tank, comprising discharging ballast water and the like, casting concrete at necessary filling portions, and backfilling around the tank after removing part of seawater.