JP2005265599A - Micro-displacement prevention structure of structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micro-displacement prevention structure having a radiation shielding function of a structure capable of preventing micro-displacement of the structure. <P>SOLUTION: A building 2 is a semi-underground structure and a surface-exposed part B is covered with soil 3 which is excavated to make the building 2. The surface of the soil 3 is covered with a sheet material 4. In addition, a pipe 5 is embedded in the soil 3 and the soil 3 is kept wet by appropriately replenishing moisture through the pipe 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a minute displacement prevention structure for a structure that needs to prevent radiation leakage and that dislikes minute displacement of a structure, such as a building containing an accelerator device or the like.

In nuclear-related facilities that handle radioactive materials, radiation shields are installed around the perimeter to prevent leakage of radiation in order to keep the high-energy radiation level leaking from the facility below the standard level stipulated by law. Generally, a concrete wall for shielding is known as a radiation shield, and the wall thickness and density are designed according to the radiation level.
Moreover, as described in Patent Document 1 and Patent Document 2, earth and sand may be used as a part of the radiation shield. In this case, by placing the target structure completely in the ground, the earth and sand that embeds the structure underground is also used as a radiation shield. That is, in order to prevent radiation from leaking from the upper part of the structure that is completely arranged underground, in the patent document 1, the upper side of the target structure 2 (the structure housing 2 that is entirely buried in the ground). On the other hand, the earth and sand are accumulated to the above-ground part or higher, and the earth and sand are made part of the radiation shield. In this way, instead of building all of the radiation shields up to the ground with concrete, the radiation shields are built using buried earth and sand, so that the shielding ability is evaluated together with the wall body and the economic efficiency is improved. Yes.

Here, the earth and sand embedded in the facility can improve the radiation shielding performance by managing the moisture content in the earth and sand and maintaining it in a certain wet state. It is preferable to use one having a high absorption rate and a low specific gravity.
In Patent Document 1, a radiation generator is housed in a target structure. However, when a high-energy particle accelerator device is assumed as the radiation generator, the accelerator device is aligned in the structure. In addition, it is necessary to prevent problems caused by shake of the optical axis of the beam due to minute displacement (about ± 0.1 mm) of the building frame (floor) during actual operation and during trial operation adjustment. Here, examples of the structure containing the accelerator include a building in which a main ring accelerator is installed in a high-energy particle accelerator facility that is expected to spread for cancer treatment and the like. Other examples include a linac accelerator facility with a long beam line and a synchrotron facility for research.
JP-A-10-68797 JP 2001-201593 A

  Here, the accelerator facility for the high energy particle accelerator device is often constructed as a ground structure rather than an underground structure mainly in the sense of lowering the construction cost of the building. For example, a proton synchrotron is used as the accelerator. For example, a medical accelerator has a diameter of at least 30 m, and the outer shape of the building is about 50 m considering the surrounding space. This accelerator device generates a particle beam of about 100 microns, and the beam is controlled by a magnet. However, if the relative displacement of the installed floor becomes larger than the beam diameter, adjustment with the magnet becomes difficult. Again, the arrangement of equipment must be adjusted. If this adjustment work is repeated, the system adjustment is delayed, and the start of operation of the facility is delayed.

In addition, after the construction of the facility, the building gradually becomes stable, but the building concrete is slightly deformed under the influence of solar radiation during the initial adjustment operation. For this reason, it is necessary to deal with it by rearranging the equipment or skillfully operating the accelerator.
The present invention has been made paying attention to such a problem, and provides a structure for preventing a minute displacement of a structure having a radiation shielding function and capable of suppressing minute displacement caused by heat and moisture of the structure. It is an issue.

In order to solve the above problems, the present invention is a micro displacement prevention structure for preventing micro displacement of a structure constructed on the ground,
Part of the structure, comprising earth and sand that covers the side wall surface and the roof surface exposed on the ground of the structure, and moisture retention adjusting means that adjusts the water content in the earth and sand to a predetermined amount. The structure is a semi-underground structure embedded in the underground, and the excavated soil generated during the burial is all or part of the earth and sand.

By covering the exposed parts with earth and sand, the structure is insulated from the heat of the outside air and solar radiation. That is, changes in the outer wall temperature that cause minute displacements are reduced by preventing the heat from fluctuating outside air and solar radiation from directly transferring heat to the housing of the structure.
Moreover, since the excavated soil generated when the structure is a semi-underground structure is used as the earth and sand that covers the structure as it is, disposal of the excavated soil becomes unnecessary.
Here, this structure is constructed on the ground, but in order to secure the earth and sand that covers the part exposed on the ground, a semi-underground structure is adopted in which the lower part is placed in the ground. It is different from a structure that is completely placed inside.

Furthermore, by maintaining the moisture content in the earth and sand at a constant level and maintaining the earth and sand in a wet state, the radiation shielding performance of the earth and sand can be improved, and the thickness of the earth and sand for radiation shielding can be suppressed. In addition, if water content is circulated and the water content in the sediment is kept at a certain level or higher, it is possible to cool the sediment with water to keep the sediment temperature within a predetermined range. In addition, the amount of minute displacement of the structure can be kept small. The water supplied to the earth and sand may be cold water or hot water.
In addition, it is desirable that the roof surface is provided with a water gradient in the direction of the outer wall so that excess water due to rainwater or the like that has entered the earth and sand is drained so that the water does not concentrate on the earth and sand above the roof surface.

  According to the present invention, it is possible to reduce the minute displacement of the structure while shielding radiation emitted from the inside of the structure at low cost.

Next, embodiments according to the present invention will be described with reference to the drawings.
FIG. 1 shows a building 2 for accommodating the accelerator device 1, and the building 2 corresponds to the structure of the present invention.
The building 2 has a semi-underground structure, and includes a lower underground portion A buried underground and an upper ground exposed portion B exposed above the ground.
And the excavated soil excavated when making the building 2 into a semi-underground structure is used as the earth and sand 3 which covers the said ground exposed part B. FIG.
Here, in this embodiment, in order to grasp the characteristics of the local soil (excavated soil) prior to excavation, a sample of the local soil is collected and a soil test such as water retention is performed. Then, based on the confirmed characteristics of the local soil, the accumulation thickness of the earth and sand 3 necessary for heat insulation and radiation shielding is obtained, and the underground buried portion A where the earth and sand 3 covering the excavated soil and the ground exposed portion B are the same amount. Find the depth of the. Then, a semi-underground structure is formed by excavating only the required depth.

The roof surface 2a of the structure is provided with a roof slab so that a water gradient is formed in the direction of the side wall 2b, and the outer periphery of the roof surface 2a is directed from the roof side toward the earth and sand 3 on the side wall 2b side. A drain 8 for guiding water is formed.
The surface of the earth and sand 3 covering the building 2 is covered with a sheet material 4. The sheet material 4 prevents scattering of the earth and sand 3 and suppresses evaporation of moisture from the earth and sand 3. Instead of the sheet material 4, a lawn or tree planting may be arranged to obtain the same effect.

Further, a sprinkling pipe 5 is arranged in the earth and sand 3. This pipe 5 is connected to the storage tank 6, and by operating the pump 7, the water in the storage tank 6 is supplied to the watering pipe 5, and earth and sand are supplied from the watering part (not shown) of the pipe 5. 3 can be supplied with water.
Further, a wet sensor 9 for measuring the water content of the earth and sand 3 is provided, and the wet sensor 9 outputs the measured detection signal to the moisture holding controller 10.

When the moisture content controller 10 determines that the moisture content in the earth and sand 3 is less than a predetermined threshold based on the signal from the wet sensor 9 so that the moisture content in the earth and sand 3 falls within a predetermined range, the operation command is sent to the pump 7. Is output to replenish moisture to the earth and sand 3.
Moreover, the side groove | channel 11 is formed so that the outer periphery of the covering earth and sand 3 may be enclosed, and the excess water from the earth and sand 3 can be discharged | emitted.
Here, the water sprinkling pipe 5, the storage tank 6, the wetness sensor 9, and the water retention amount controller 10 constitute a water retention amount adjusting means.

Next, functions and effects of the above configuration will be described.
According to this structure, since the entire building 2 is not buried in the ground, the construction cost of the building 2 can be suppressed.
Moreover, even if it is a semi-underground structure, it becomes unnecessary to dispose of the excavated soil generated at the time of excavation by using the excavated soil at that time as the earth and sand 3 for preventing minute displacement, leading to cost reduction.
Further, by paying attention to the ground exposed portion B of the building 2 and covering the portion with the earth and sand 3, the temperature change of the building 2 due to outside air and solar radiation can be suppressed small, and as a result, the minute displacement of the building 2 can be suppressed. It becomes possible. As a result, the adjustment period of the equipment operation is shortened, and the delay in the operation start time of the facility can be prevented.

In addition, since the earth and sand 3 also acts as a radiation shield by covering with the earth and sand 3 made of excavated soil at the site, the outer wall and roof slab of the building 2 that requires thick shielding concrete is thinned accordingly. Construction is also possible.
At this time, since the wet state of the earth and sand 3 is maintained and managed, the radiation shielding performance by the earth and sand 3 is improved, and the amount of sediment 3 deposited can be reduced, and it can function effectively as a neutron shield. To do.

Furthermore, even if the dismantling of the building 2 is assumed, only a part of the building 2 is located in the basement in a semi-underground structure, and the covering earth and sand 3 covers only the exposed ground part. Therefore, since the earth and sand 3 can be easily removed, the building 2 can be easily disassembled because the shielding concrete can be made thinner as described above.
In addition, the roof slab is provided with a water gradient in the direction of the outer wall, and the drain 8 for draining excess moisture due to infiltrated rainwater or the like is installed, so that it is possible to prevent excessive moisture from being stored on the roof surface 2a. .

Moreover, in this embodiment, evaporation of a water | moisture content from the earth and sand 3 is suppressed by the sheet | seat material 4 etc., and adjustment of the moisture content of the earth and sand 3 is easy to that extent. In addition, when the sheet material 4 is used, the intrusion of rainwater into the earth and sand 3 is suppressed to be small, and the water content of the earth and sand 3 can be easily adjusted from this point.
Here, in the said embodiment, although the earth and sand 3 are comprised only with excavated soil, it is not limited to this. You may make it supplement the earth and sand 3 from others by increasing the quantity of the earth and sand 3 rather than excavated soil (that is, reducing the underground burying part A).
Further, the moisture content adjusting means is not limited to the above configuration. In short, as long as the earth and sand 3 can be held in a wet state with a predetermined water content, other moisture content adjusting means may be employed.

It is a figure which shows the micro displacement prevention structure which concerns on embodiment based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Accelerator apparatus 2 Building 2a Roof surface 2b Side wall 3 Earth and sand 4 Sheet material 5 Piping 6 Storage tank 7 Pump 8 Drain 9 Wet sensor 10 Moisture retention controller 11 Side groove

Claims (1)

A micro displacement prevention structure that prevents micro displacement of a structure constructed on the ground,
Part of the structure, comprising earth and sand that covers the side wall surface and the roof surface exposed on the ground of the structure, and moisture retention adjusting means that adjusts the water content in the earth and sand to a predetermined amount. A structure for preventing micro displacement of a structure, characterized in that a semi-underground structure is embedded in the basement, and excavated soil generated during the embedding is all or part of the earth and sand.

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