JPH0646080B2 - Underground tank with built-in wall with freezing pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a wall-integrated type having a freezing pipe for stopping leakage of water generated at the side of an LPG underground tank or the like by freezing the side wall of the tank. Regarding underground tanks.

[Conventional technology]

The installation structure of an underground tank side wall in which a continuous underground wall is provided in the ground and a tank side wall is constructed inside the continuous underground wall is generally shown in FIGS. 7 and 8. 7th
In FIG. 8 and FIG. 8, reference numeral 1 is a continuous underground wall (hereinafter, simply referred to as “continuous wall”), and reference numeral 2 is a tank side wall.

The underground tank side wall installation structure shown in FIG. 7 is of a type in which the connecting wall 1 and the tank side wall 2 are separated from each other, and the underground tank shown in FIG. It is a built-in connecting wall type in which the connecting wall 1 and the tank side wall 2 are integrated to form the main structure of the side wall of the underground tank. The type with a built-in connecting wall shown in FIG. 8 requires less soil excavation when constructing an underground tank, as compared with the type shown in FIG. 7 in which the connecting wall 1 and the tank side wall 2 are separated from each other. ,Also,
There are advantages such as the small amount of concrete used.

However, in the underground tank with a built-in continuous wall, it is difficult to take a water-stop structure such as covering the outside of the side wall with an iron plate when stopping the side water. There is. Next, a water stop structure of a wall-incorporating type will be described with reference to FIGS. 9 and 10. FIG. 9 and FIG. 10 show an installation structure of a side wall built-in type underground tank side wall. Figure 9 shows
It is an installation structure of the underground tank side wall by the water stop system on the side wall inner surface. In the figure, reference numeral 3 is a connecting wall. An inner winding part 4 is constructed on the inner side of the connecting wall 3, and a water stop plate 5 of an iron plate is installed on the inner side surface of the inner winding part 4. Also, the wall 3
A pressure-preventing filter 6 is installed between the inner winding part 4 and the inner winding part 4. The pressure prevention filter 6 is widely used as a water collecting and drainage material in the field of civil engineering, and for example, a material in which fibers are accumulated in a non-woven state or a material formed of a porous material is generally used. The water that has entered the inside of the connecting wall 3 from the inside is collected by the pressure-preventing filter 6 and guided to the lower drainage channel for draining.
Next, FIG. 10 shows an installation structure of the side wall of the underground tank by a water drop method. In the figure, reference numeral 7 is a connecting wall. An inner winding portion 8 is constructed inside the connecting wall 7, and a drainage material 9 is installed between the connecting wall 7 and the inner winding portion 8.

[Problems to be solved by the invention]

However, in the conventional installation structure of the underground wall built-in underground tank side wall configured as described above, when used for a long time,
In the case where the inner wall of the side wall has a water stop system, the water stop plate 5 may be pressed due to clogging of the pressure filter 6. That is, when the pressure-preventing filter 6 is clogged, the water collected in the pressure-preventing filter 6 is not drained but is accumulated in the pressure-preventing filter 6 as it is, and the water pressure is gradually increased. If a crack is generated in the inner winding portion 4, it will penetrate into the underground tank from there and water pressure will be applied to the water blocking plate 5 from the outside. Further, the water leakage type has a problem that the water stopping function is deteriorated due to clogging of the drainage material 9 and lacks reliability.
The above water stop structure has problems such as high construction cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a structure for installing a side wall-embedded underground tank side wall that has a reliable waterproof structure and is inexpensive to construct.

[Means for solving problems]

According to the present invention, a freezing pipe is provided in the entire inner wall of the continuous wall embedded type underground tank side wall in which the inner roll is provided adjacent to the inside of the continuous underground wall. And set up
A heater is provided in the ground on the outer peripheral side of the continuous underground wall over the entire area in the height direction of the inner winding part, and a cooling liquid is introduced into the freezing pipe and the heater is heated to form an inner winding. It is characterized in that a connection area which does not reach the ground on the outer peripheral side of the continuous underground wall is provided in the portion and the continuous underground wall.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
The present invention is applied to the case where the liquid stored in the underground tank has a relatively high liquid temperature (-45 ° C to -5 ° C) such as LPG.

FIG. 1 is a view showing a main part of an installation structure of a side wall built-in type underground tank side wall having a freezing pipe, and FIG. 2 is a plan view of FIG. In the figure, reference numeral 10 is the ground. A cylindrical connecting wall 11 is installed on the ground 10, and an inner winding portion 12 is built inside the connecting wall 11 by connecting to the connecting wall 11. This underground tank side wall installation structure is
1 and the inner winding part 12 are integrated to form a continuous wall built-in type, which is the main body of the side wall structure of an underground tank. A bottom slab 13 is provided at the bottom of the inner winding part 12, and a bottom drainage layer 14 is provided below the bottom slab 13 so as not to receive groundwater pressure. On the other hand, a tank roof portion 15 is installed above the inner winding portion 12, and LPG (liquid temperature -4
5 ° C to -5 ° C) 16 is stored. In addition, the inner winding part 1
Inside the 2, a freezing pipe (cooler) 17 is installed. The freezing pipes 17 are arranged inside the inner winding part 12 at equal intervals along the circumferential direction and so as to extend vertically from the upper part to the bottom part of the inner winding part 12. Further, in the vertically arranged freezing pipe 17, every other pipes adjacent to each other in the upper part are connected, and in the lower part, adjacent pipes which are not connected to each other in the upper part are connected to each other so that the inner pipe as a whole is connected. It is one pipeline that meanders in the winding part 12.

The freezing pipe 17 is connected to the cooling liquid supply device 20 via a heat exchanger 19 on the ground. In addition, the freezing pipe 17 is filled with a brine liquid 17a which is a cooling liquid as a heat medium, and is circulated in the freezing pipe 17 sequentially. Inside the cooling liquid supply device 20, a cooling liquid (LNG, LN ₂ or the like is used) 2 for cooling the brine 17a is used.
0a is filled, and heat is exchanged with the brine 17a via the heat exchanger 19. Further, a heater 21 is embedded in the ground 10 on the outer periphery of the connecting wall 11. The heaters 21 are arranged at equal intervals in the circumferential direction along the connecting wall 11 and at a predetermined distance on the extension line of the freezing pipe 17 and the connecting wall 11 in the radial direction so as to overlap each other. There is.

In addition, in the above-mentioned structure, the freezing pipe 17 is divided into a plurality of pipes, and the heat exchanger 19 and the cooling liquid supply device 20 are provided in each of them.
It is good also as a structure which arranged.

In the installation structure of the underground wall side wall built-in type tank having the freezing pipe having such a configuration, the brine liquid 17a circulating in the freezing pipe 17 is supplied by the cooling liquid supply device 20 and circulated in the heat exchanger 19. Coolant (LNG)
20a is heat-exchanged and cooled.

The cooled brine liquid 17a circulates in the freezing pipe 17 to cool the inner winding portion 12 and the interior of the communicating wall 11. Therefore, the leaked water existing inside the inner winding portion 12 and the connecting wall 11 is sequentially cooled and frozen to form an ice wall inside the inner winding portion 12 and the connecting wall 11. Therefore, the groundwater from the ground 10 will block the water channel to the side wall of the underground tank, and will not be able to enter the underground tank, and the water will be stopped. Further, the heater 21 embedded in the ground 10 on the outer peripheral portion of the connecting wall 11 is provided with the ground 1 near the outer peripheral portion of the connecting wall 11.
By warming 0, it will prevent it from freezing and producing frozen soil. In this way, in the installation structure on the side of the underground wall embedded type underground tank having the frozen pipe, the inner winding part 1
2. By forming a freezing zone in the continuous underground wall 11 that does not reach the ground on the outer peripheral side of the continuous underground wall 11, it is possible to reliably stop the water in the side portion of the underground tank.

Next, in the installation structure of the continuous wall built-in type underground tank side wall having the freezing pipe in this example, that is, in the freeze-stop water structure of the underground tank side wall by the combination of the cooler (freezing pipe) 17 and the heater 21, Whether or not such freeze-stopping is possible will be described based on the analysis results obtained by using the plane fan model heat conduction analysis.

This model analysis is to set the following three conditions and to find the combination of the cooler and heater tube surface temperatures required to satisfy these three conditions.

(1) A freezing area of 20 cm or more exists inside the inner winding part 12.

(2) The frozen area (0 ° C line) does not reach the ground 10.

(3) Cooler (freezing pipe) 17 and heater 21
Even if there is a temperature difference of ± 3 ° C in the case of the above condition (1)
Satisfaction of (2).

It should be noted that the above condition (3) is basically the same even if errors occur within a maximum of ± 3 ° C, considering that it is inevitable that some errors will occur in the cooler and heater surface temperatures. These are additional conditions set to satisfy the general conditions (1) and (2).

Next, a plane sector model for satisfying the above conditions is set as shown in FIGS. In FIGS. 3 to 5, the wall thickness a of the inner winding portion 12 is a = 0.8 m, the wall thickness of the connecting wall 11 is b = 1 m, and the distance c = 0 from the inner edge of the inner winding portion 12 to the freezing pipe 17. The distance d from the outer edge of the connecting wall 11 to the heater 21 is d = 1 m, and the installation interval e of the freezing pipe 17 and the heater 21 in the circumferential direction is 6 °.

Next, various calculation conditions set for the analysis are shown below.

(i) Liquid temperature in underground tank… 0 ℃ (ii) Cooling performance… PUF 65mm equivalent (iii) Thermal conductivity… PUF 0.023Kcal / mh ℃ Concrete 2.0Kcal / mh ℃ Ground 1.53Kcal / mh ℃ ( iv) Tube surface temperature of the freezing pipe 17 ... -24 ° C to -4.5 ° C Tube surface temperature of the heater 21 ... 12 ° C to 28 ° C Based on the above conditions, the freezing pipe 17 and the heater 21
The analysis was carried out for the case where the set temperature of 3 was the case of FIG. 3 to FIG. As a result, when the set temperature of the freezing pipe 17 is T ₁ and the set temperature of the heater 21 is T ₂ ,
FIG. 3 shows T ₁ = −12 ° C., T ₂ = 21 ° C., and FIG. 4 shows T ₁
= -9 ° C, T ₂ = 24 ° C, Fig. 5 shows T ₁ = -15 ° C, T
It is a temperature distribution diagram by analysis when ₂ = 18 ° C. In these figures, the freezing zone generated on the side wall is 1.25 m from the inner edge of the inner winding part 12 in FIG. 3, 0.6 m from the inner edge of the inner winding part 12 in FIG. It is 1.75 m from the inner edge of the winding part 12, and in any case, the basic conditions (1) and (2) described above, that is, there is a frozen region of 20 cm or more inside the inner winding part 12, and This satisfies the condition that the frozen area does not reach the ground 10.

In addition, when these analysis results are represented graphically,
The relationship of the pipe surface temperature combination diagram of the cooler 17 and the heater 21 shown in the figure is established. In FIG. 6, a line P indicates a boundary satisfying the condition (1), the condition (1) is satisfied in the region below the line P, and a line Q satisfies the condition (2). This shows the boundary to be satisfied, and the condition (2) is satisfied in the region above the line Q. Therefore, the area between the line P and the line Q is an area where both conditions (1) and (2) are simultaneously satisfied. In addition, the region R shown as a shaded area is the condition (1).
In addition to (2), the condition (3) is also satisfied at the same time, and this region R is a range that satisfies a stricter condition in consideration of the error of the tube surface temperature.

Therefore, as shown in FIG. 6, the combination of the set temperatures in the cases of FIGS. 4 and 5 has a basic condition (1).
(2) is satisfied, and the combination of set temperatures in the case of FIG. 3 satisfies not only the conditions (1) and (2) but also the stricter additional condition (3) considering the error of the pipe surface temperature. It will be done.

〔The invention's effect〕

As described above, the continuous wall built-in type underground tank having the freezing pipe according to the present invention is provided with the freezing pipe in the inner winding part over the entire height direction of the inner winding part and the continuous underground wall. A heater is provided in the ground on the outer peripheral side of the inner winding part over the entire height direction, and a cooling liquid is introduced into the freezing pipe and the heater is heated to form an inner winding part and a continuous underground wall. Since there is a freezing zone on the outer peripheral side of the continuous underground wall that does not reach the underground, only the side wall can be frozen without generating frozen soil around the side wall of the underground tank. It is possible to realize an installation structure of a side wall embedded underground tank side wall with a reliable water structure and a low construction cost.

[Brief description of drawings]

1 and 2 are views showing an embodiment of the present invention,
FIG. 1 is a view showing a main part of an installation structure of a side wall embedded underground tank side wall having a freezing pipe, FIG. 2 is a plan view of FIG. 1, and FIGS. The calculation results of conducting a plane fan model heat conduction analysis are shown for the examples, FIGS. 3 to 5 are temperature distribution diagrams at each set temperature, and FIG. 6 is a pipe surface temperature of a cooler and a heater. FIG. 7 is a combination view, and FIG. 7 to FIG. 10 are views showing a conventional technique, and FIG. 7 is a view showing a main part of an installation structure of an underground tank side wall in which a connecting wall and a tank side wall are separated from each other. Yes, FIG. 8 is a view showing a main part of an installation structure of a side wall embedded underground tank side wall, and FIG. 9 is a view showing a main part of an installation structure of an underground tank side wall of a side wall internal water stop system. FIG. 10 is a view showing a main part of an installation structure of a side wall of an underground tank of a water drop type. 10 ... Ground, 11 ... Continuous underground wall (continuous wall), 12 ...
Inner winding part, 17 ... Freezing pipe (cooler), 17a ...
Coolant (brine liquid), 21 ... Heater.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yuichi Kikuchi, 2-16-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. (72) Kazuhiro Miura 2--16-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. (56) Bibliographic Reference Showa 48-40812 (JP, U)

Claims (1)

[Claims] 1. A structure for installing a continuous wall embedded type underground tank side wall in which a continuous underground wall which is a still water retaining wall is provided underground, and an inner winding portion is provided adjacent to the inside of the continuous underground wall. In the inner winding portion, a freezing pipe is provided over the entire height direction of the inner winding portion, and a heater is provided in the ground on the outer peripheral side of the continuous underground wall in the height direction of the inner winding portion. The cooling liquid is introduced into the freezing pipe and the heater is heated so that the inner winding portion and the continuous underground wall do not reach the underground on the outer peripheral side of the continuous underground wall. An underground tank with a built-in wall that has a freezing pipe, characterized by having a freezing zone.