JPS62141260A - Construction method for sinking existing structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for submerging existing structures such as nuclear power plants.

<Prior Art> Currently, the following three methods exist internationally for the disposal of existing structures, for example nuclear reactors.

(1) Sealed control method (2) Shielding method (3) Demolition and removal method The selection of these three methods is determined by various conditions.
In the case of Japan, in view of the current situation that the country has a small land area, the development of the method (3) is being promoted based on various conditions such as the effective use of land.

Problems to be Solved by the Present Invention> There are the following problems when adopting the waste treatment method (3) above.

(b) The dismantling of nuclear reactor containment facilities will generate a large amount of radioactive waste, which will have a major impact on the human body and the surrounding environment.

In particular, sufficient consideration must be given to the radiation exposure of workers.

) Post-treatment of radioactive waste generated by demolition will be necessary.

(c) In order to minimize the risk of exposure to radiation, it is necessary to develop special machinery for demolition.

Purpose of the Invention The present invention was made to solve the above-mentioned problems, and does not require post-treatment of radioactive waste. The purpose of this project is to provide a method for submerging existing structures that is highly safe and does not have any negative effects on the human body or the surrounding environment due to radioactivity.

Furthermore, the present invention allows all kinds of existing structures to be efficiently (
The purpose of this project is to provide a method for submerging existing structures.

Structure of the present invention> The present invention enables the existing structure to be moved to a predetermined location without dismantling the existing structure, and then removing backfilling material such as earth and sand directly under the existing structure. This is a method of lowering it into the ground and depositing it.

Hereinafter, a method for submerging an existing structure according to the present invention will be described with reference to the drawings, and a nuclear reactor containment facility will be described as an example of the existing structure.

(1) Opening a buried hole (Figure 1) In Figure 1, a buried hole 2 will be opened near the reactor containment facility.

This immersion hole 2 is a hole for burying a nuclear reactor containment facility underground.

If the ground at the bottom of the hole 2 is hard like bedrock,
No special reinforcement is required, but in places where the rock is difficult to stand on its own, a combination of rock bolts and sprayed concrete or reverse-rolled concrete will be used to excavate to a specified depth.

Further, if collapse of the hole wall of the immersed hole 2 is expected, a retaining wall 21 such as steel sheet piles or reverse-wound concrete is constructed to cope with the collapse.

(2) Backfilling of the buried hole (Figure 2) Next, the completed buried hole 2 is filled with backfilling material 3 such as sand, and the expansion pressure is repeated.

This backfilling work is performed on the ground that can withstand the total weight of the reactor containment facility and the submerged pedestal 4, as will be described later.

(3) Setting the submerged pedestal After completing the backfilling work, place the submerged pedestal 4 on the top surface of the submerged hole 2.
Place.

The submersion stand 4 is a member for the purpose of placing the reactor containment facility 1 and making it reach the bottom of the submersion hole 1, and is formed into a flat plate having a circular or rectangular shape.

The submerged pedestal 4 can be constructed, for example, in the same manner as a working chamber for a pneumatic caisson.

(4) Moving the reactor containment facility and placing it on the pedestal (Fig. 3) The reactor containment facility is left standing (without disassembling it, the entire structure is moved horizontally and placed on the submerged pedestal 4).

Incidentally, as shown in FIG. 6, a part of the reactor containment facility may be dismantled and only the reactor core 11 may be placed on the submerged pedestal 4.

(5) Sinking (Figure 3.5) While excavating the backfill material 3 on the lower surface of the submerged pedestal 4 evenly, the submerged pedestal 4 carrying the reactor containment facility is gently lowered.

As a method for excavating the backfill material 3, for example, as shown in FIG. In addition to the method of excavating the backfill material 3 with an excavating machine 6 located on the ground side, there is also a method of sucking and discharging the backfill material 3 with a sand pump or the like.

Furthermore, in order to maintain the stability of the submerged pedestal 4 by increasing the outer peripheral area of the submerged pedestal 4 that comes into contact with the backfilling material 3, it is also possible to extend and form a temporary wall 41 on the top surface of the submerged pedestal 4. be.

As described above, the reactor containment facility is lowered together with the submerged pedestal 4 and is brought to the bottom of the submerged hole 2.

(6) Concrete filling (Fig. 4) Once the reactor containment facility has reached the bottom, all backfilling timber remaining on the side wall of the immersion hole 2 will be excavated.

Concrete 5 is then filled throughout the reactor containment facility 1, the submerged pedestal 4, and the immersed hole 2 to integrate it with the surrounding ground, and the disposal work for the reactor containment facility is completed.

Other Embodiments In the embodiments described above, the case where earth and sand is used as the backfilling material 3 has been described, but it is also possible to use a liquid such as water.

In the case of this embodiment, the submerged pedestal 4 is provided with a function as a float.

Furthermore, in the embodiment described above, the structure was buried with concrete to prevent the leakage of radioactivity, but depending on the type of existing structure, it may be buried with a material other than concrete, such as earth and sand or leftover soil.

Effects> Since the present invention is as explained above, the following effects can be obtained.

(b) Since the reactor containment facility can be buried underground without being dismantled, there was no concern that radioactivity would leak outside during disposal work.

Since the reactor containment facility is completely enclosed in concrete even after burial, it not only has an extremely high shielding effect, but also maintains safety against radioactivity leakage semi-permanently.

(c) Since an immersed hole will be constructed near the reactor containment facility,
The lateral movement distance of the reactor containment facility is reduced.

2〉It can be used for disposal of various existing structures and has wide versatility.

[Brief explanation of drawings]

Figure 1: An explanatory diagram of the state of construction of a buried hole. Figure 2: An explanatory diagram of the backfilling state. Figure 3: An explanatory diagram of the reactor containment facility when it is submerged. figure

Claims (1)

[Claims] An immersion hole is constructed near an existing structure, the immersion hole is backfilled, a pedestal for mounting the existing structure is placed on top of the backfilling material, and the existing structure is moved laterally. A method for submerging an existing structure, in which the existing structure is placed on the pedestal, and the pedestal and existing structure are brought to the bottom while the backfill material below the pedestal is discharged out of the hole.