JP6650271B2 - Low temperature underground tank - Google Patents

Description

  The present invention relates to a low-temperature underground tank for storing low-temperature liquefied gas and the like.

  There is a low-temperature underground tank as a facility for storing low-temperature liquefied gas such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas). FIG. 3A shows an example of the low-temperature underground tank 100. The low-temperature underground tank 100 is an underground structure in which a reinforced concrete underground continuous wall 31 is excavated in the inner ground 2 as a ridge reaching an impermeable layer to construct a skeleton. The skeleton is generally composed of a slab 11 made of reinforced concrete, a cylindrical side wall 12 formed on the slab 11, and a roof 13 made of steel. A heat insulating material, a membrane (not shown), and the like are also installed on the inner surfaces of the bottom plate 11 and the side walls 12.

  In the low-temperature underground tank 100, a water collecting layer 15 made of crushed stone or the like is formed below the bottom plate 11 for controlling the water level below the bottom plate (for example, see Patent Documents 1 and 2). The groundwater collected in the water collecting layer 15 is drained to the ground by two to four pumping pipes 41. Although not particularly shown, a water pump, a discharge pipe, a water level gauge, and the like are arranged in the water pump 41. The lower part of the pumping pipe 41 is connected to the water collecting layer 15 by the communication pipe 42.

  FIG. 3B is a diagram showing the pumping pipe 41, which is a horizontal sectional view of the pumping pipe 41, the underground continuous wall 31, and the like. As the pumping pipe 41, a double pipe type in which an inner pipe 412 is inserted inside an outer pipe 411 is adopted. A heat insulating material 413 such as foam glass or polyurethane foam is wound around the outside of the inner tube 412, and a waterproof material (not shown) is applied to the outside of the heat insulating material 413.

  The pumping pipe 41 is generally buried in the convex portion 31a of the underground continuous wall 31 so as to have the same behavior (deformation) as the low-temperature underground tank 100 during an earthquake. The convex portion 31a is provided so as to protrude from the underground continuous wall 31 to the surrounding ground 2 side, and the end of the pumping pipe 41 on the tank side (corresponding to the left side in FIG. 3B) is flat. Is often arranged to be continuous with the rising portion 311 of the convex portion 31a of the underground continuous wall 31.

  Outside the side wall 12 of the low-temperature underground tank 100, a plurality of vertical side heater tubes 51 are arranged. In the example of FIG. 3, the side heater tube 51 is buried in the ground 2 at a position about 2 m away from a fixed thickness portion (a portion other than the convex portion 31 a) of the underground continuous wall 31. Note that some of the side heater tubes 51 are embedded in the convex portions 31 a of the underground continuous wall 31.

  The side heater pipe 51 warms the ground 2 with the warm water circulating inside and controls the freezing range of the ground 2 outside the low-temperature underground tank 100. Thus, the operation is controlled such that the freezing line 22 (outer edge of the freezing range) is located at a position approximately 1 m away from the outer surface of the constant thickness portion of the underground continuous wall 31. The heat insulating material 413 provided between the inner and outer pipes of the pumping pipe 41 prevents the freezing line 22 from entering the inner pipe of the pumping pipe 41 and prevents the inner surface of the pumping pipe 41 and the discharge pipe from freezing.

JP 2000-211688 A JP 2001-122384 A

  The pumping pipe 41 is formed by laying the outer pipe 411 at the time of constructing the underground continuous wall 31 and laying the inner pipe 412 wrapped with the heat insulating material 413 inside the outer pipe 411 at the stage when the construction has progressed. . However, the gap between the inner and outer tubes is often as small as less than 100 mm, and the heat insulator 413 is easily damaged when the inner tube 412 is inserted.

  In addition, since the outer pipe 411 is as long as, for example, about 50 m, if there is a height difference in the concrete placement height of the underground continuous wall near the pumping pipe 41, the outer pipe 411 is easily bent due to the difference in the placement pressure. . If bending remains in the outer tube 411, the straight inner tube 412 competes, and it becomes difficult to insert the inner tube 412.

  Furthermore, a waterproof layer is provided on the outside of the heat insulating material 413 by applying a waterproof material. However, if moisture enters between the inner and outer tubes, the heat insulating performance is reduced, and the inner surface of the inner tube may freeze. Also, dew condensation easily occurs between the inner and outer pipes due to a change in outside air temperature, and the dew turns into water due to a rise in temperature and accumulates on the lower surface between the inner and outer pipes. As a result, the heat insulating material may be immersed in water and the heat insulating performance may be impaired.

  The present invention has been made in view of the above problems, and has as its object to provide a low-temperature underground tank having a reasonable pumping pipe structure.

The present invention for solving the above-mentioned problem is a low-temperature underground tank provided on the ground, comprising a bottom plate, a cylindrical side wall formed on the bottom plate, and a continuous underground provided outside the side wall. A wall, a single pumping pipe for pumping water from below the bottom slab, and a plurality of heater pipes including those provided on the ground outside the underground continuous wall , wherein the pumping pipe is A low-temperature underground tank, which is arranged at a position outside a freezing range of the ground controlled by a plurality of heater pipes.

  In the present invention, since the pumping pipe is outside the freezing line, the inner surface of the pumping pipe does not freeze, and there is no need to provide a heat insulating material between the inner and outer pipes as a conventional pumping pipe as a double pipe. . Therefore, the pumping pipe can be configured as a simple single pipe, and there is no problem such as competing against the outer pipe or damaging the heat insulating material when inserting the inner pipe as in the past. Can be planned. Also, even if dew condensation occurs on the inner surface of the pumping pipe and becomes condensed water and falls to the bottom of the pumping pipe, it is not a problem because the pump is only pumped up.

The underground continuous wall, have a convex portion projecting ground side around the riser pipe is preferably provided in the convex portion of the diaphragm wall.
Since the pumping pipe is buried and integrated with the convex part of the underground continuous wall, it can be deformed similarly to the low-temperature underground tank and has no stress problem. In addition, the pumping pipe can be built when the underground diaphragm wall is constructed, and the construction period can be shortened because there is little post-construction work.

It is preferable that the pumping pipe is for pumping groundwater from a water collecting layer below the bottom plate.
As described above, the present invention can be suitably applied to a water pump for pumping groundwater from a water collecting layer below a bottom plate.

  According to the present invention, a low-temperature underground tank having a reasonable pumping pipe structure can be provided.

Diagram showing low-temperature underground tank 1 Diagram showing anchor 414 Diagram showing low-temperature underground tank 100

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(1. Low temperature underground tank 1)
FIG. 1 is a diagram showing a low-temperature underground tank 1 according to an embodiment of the present invention. FIG. 1A is a diagram illustrating an outline of the low-temperature underground tank 1, and FIG. 1B is a diagram illustrating a pumping pipe 41a. FIG. 1B shows a horizontal cross section of the pumping pipe 41a, the underground continuous wall 31, and the like.

  The low-temperature underground tank 1 stores low-temperature liquefied gas such as LNG and LPG, and like the low-temperature underground tank 100, a slab 11 made of reinforced concrete, a cylindrical side wall 12 formed on the bottom slab 11, and a steel plate. The skeleton formed of the roof 13 is provided on the ground 2. On the ground 2 outside the side wall 12, an underground continuous wall 31 reaching the water-impermeable layer is provided. A water collecting layer 15 made of crushed stone or the like is provided below the bottom slab 11, and groundwater is pumped from the water collecting layer 15 by the water pumping pipe 41a. Outside the side wall 12, a plurality of vertical side heater tubes 51 are arranged to control the freezing range of the ground 2. The description of other points similar to those of the low-temperature underground tank 100 will be omitted. Note that the term “outside” refers to a direction opposite to the direction toward the tank side, and corresponds to the right side in FIGS.

  The low-temperature underground tank 1 differs from the low-temperature underground tank 100 in the configuration related to the pumping pipe 41a. That is, in the present embodiment, the pumping pipe 41a is a single pipe type constituted by a single pipe, and the heat insulating material and the like are omitted.

  The pumping pipe 41a has a tank-side end inside a convex portion 31a protruding from the underground continuous wall 31 to the surrounding ground 2 side and an outer surface of a constant thickness portion (a portion other than the convex portion 31a) of the underground continuous wall 31. It is provided so as to be located at a position about 1.5 m away from the outside.

  On the other hand, the freezing line 22 (outer edge of the freezing range) is controlled by the side heater tube 51 to a position away from the outer surface of the constant thickness portion of the underground continuous wall 31 by 1 m outside as described above. Accordingly, the water pump 41a is disposed at a position outside the freezing line 22. For this reason, in the present embodiment, freezing does not occur on the inner surface of the pumping pipe 41a or the like, and as described above, a heat insulating material or the like becomes unnecessary.

  In addition, the upper part of the ground 2 is the embankment part 23, and the pumping pipe 41a is built when the underground continuous wall 31 is constructed. After the construction, the concrete 32 is provided outside the pumping pipe 41a.

  As described above, in the present embodiment, since the pumping pipe 41a is located outside the freezing line 22, the inner surface of the pumping pipe 41a does not freeze. There is no need to provide a heat insulating material in the vehicle. Therefore, the pumping pipe 41a can be configured as a simple single pipe, and there is no problem of competing with the outer pipe or damaging the heat insulating material at the time of inserting the inner pipe as in the related art, so that the construction is simple and the construction cost is reduced. Can be achieved. Also, even if dew condensation occurs on the inner surface of the pumping pipe 41a and becomes condensed water and falls to the bottom of the pumping pipe 41a, it is not a problem because it is only pumped together with groundwater by a pump or the like.

  In addition, since the pumping pipe 41a is buried and integrated with the convex portion 31a of the underground continuous wall 31, it can be deformed similarly to the low-temperature underground tank 1, and there is no stress problem. In addition, the pumping pipe 41a can be built when the underground continuous wall 31 is constructed, and the construction period can be shortened because there is little post-construction.

  However, the present invention is not limited to the above embodiment. For example, the low-temperature underground tank 1 of the present embodiment is a tank that stores a low-temperature liquefied gas such as LNG or LPG, but is not limited thereto, and may be any tank that stores at least a temperature of less than 0 ° C.

  Further, the pumping pipe 41a of the present embodiment is for pumping groundwater in the water collecting layer 15 for controlling the water level below the bottom plate, and the present invention can be suitably applied to such a pumping pipe 41a. However, the pumping pipe 41a is not limited to this, and may be a pump that pumps and recovers this hot water, for example, in a bottom heater (not shown) that allows hot water to flow through the crushed stone layer under the bottom plate of the low-temperature underground tank 1. .

  Further, as shown in FIG. 2, the pumping pipe 41a may be fixed to the concrete of the convex portion 31a by the anchor 414. This prevents a gap from being formed between the pumping pipe 41a and the concrete, and prevents the pumping pipe 41a from buckling due to freezing of water that has entered the gap. In addition, the pumping pipe 41 a does not necessarily have to be embedded in the convex portion 31 a of the underground continuous wall 31, and may be embedded in the ground 2 outside the freezing line 22. Further, the position of the water pump 41 a is not particularly limited as long as it is outside the freezing line 22.

  As described above, the preferred embodiments of the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be made within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. I understand.

1, 100; low temperature underground tank 2; ground 11, bottom plate 12, side wall 13, steel roof 15, water collecting layer 22, freezing line 23, embankment 31, underground continuous wall 31a, convex 32, concrete 41, 41a. Pump pipe 42; communication pipe 51; side heater pipe 411; outer pipe 412; inner pipe 413; heat insulating material 414;

Claims (3)

A low-temperature underground tank installed on the ground,
The bottom plate,
A cylindrical side wall formed on the bottom plate;
An underground continuous wall provided outside the side wall,
A single pumping pipe for pumping water from below the bottom plate,
A plurality of heater tubes including those provided on the ground outside the underground continuous wall ,
With
The low-temperature underground tank, wherein the pumping pipe is disposed at a position outside a freezing range of the ground controlled by the plurality of heater pipes. The underground continuous wall, have a convex portion projecting ground side around,
The low-temperature underground tank according to claim 1, wherein the pumping pipe is provided in the projection of the underground continuous wall.   The low-temperature underground tank according to claim 1, wherein the water pump pipes ground water from a water collecting layer below the bottom slab. 4.

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