JP4958612B2 - Seismic isolation structure - Google Patents

Description

The present invention covers the whole or a part of a site such as a tank yard or a plant yard, and provides a seismic isolation structure and seismic isolation that forms a ground block in which seismic waves from the outside are not easily transmitted by providing a seismic isolation layer in the ground. It relates to the construction method of the structure.

In a floating roof type liquid fuel tank, sloshing occurs during an earthquake, and damage such as damage to the floating roof or fire due to exposure of the liquid level may occur.

In order to prevent damage from sloshing, there are various operational methods such as increasing the strength of the tank itself so that the tank will not be damaged even if sloshing occurs, or leaving the liquid level in the tank resonating during an earthquake for a long time. Neither method is realistic. For this reason, the seismic isolation method which suppresses the vibration by an earthquake is desired.

As a method for seismic isolation of such a structure, the base on which the structure is placed is insulated from the surrounding ground, and a base isolation base is provided with a base isolation device interposed between them. In view of the above, there is a seismic isolation method for determining the depth and area of the base isolation ground (Patent Document 1).

In addition, for the ground of the entire site or the entire city area, a seismic isolation layer is interposed between the bottom surface of the ground block to be seismically isolated and the base, and side surface exemption is provided between the side of the ground block and the base. There is a seismic isolation structure with an earthquake barrier layer (Patent Document 2).
Japanese Patent Laid-Open No. 10-299025 JP-A-9-221767

However, in the method described in Patent Document 1, since the tank which is an individual structure is a huge structure, the seismic isolation device becomes large for such a foundation, especially in the construction for existing tanks. There is a problem that is not economical. In addition, because pipes connected to the tank are connected to the outside, even if the tank itself can be isolated, there is a risk that the connection with the pipe will be damaged due to unequal subsidence during an earthquake. .

In addition, in the seismic isolation structure described in Patent Document 2, since the base isolation layer is provided to isolate the entire site, the seismic isolation layer can be isolated over a wide area of the tank yard. And the seismic isolation structure installed in the concrete layer, application to a large area such as a tank yard requires a large number of man-hours, is not economical, and is particularly difficult to apply to an existing tank yard. There is a problem that.

The present invention has been made in view of such problems, and is intended for the whole or part of a site such as a tank yard or a plant yard, and a seismic isolation layer that does not require a special seismic isolation device or the like in the ground. The purpose is to provide a seismic isolation structure that forms a ground block that is difficult to transmit seismic waves from the outside, and a method for constructing the base isolation structure.

In order to achieve the above-described object, the first invention penetrates a continuous wall of the shaft from a predetermined depth in a groove-shaped shaft disposed at at least one end of the ground of an area where seismic isolation is performed. A seismic isolation layer filled with a seismic isolation material that liquefies due to vibration when an earthquake occurs, and the seismic isolation layer is formed at the end of the excavation hole. The base isolation structure is formed by sealing the base isolation material in the excavation hole with mortar filled in a portion .

A partition with a pipe roof is provided at the upper part of the seismic isolation layer so that the seismic isolation material and the upper ground of the seismic isolation layer are not mixed by the vibration to prevent deterioration of the function of the seismic isolation layer. It may be a thing . The seismic isolation material liquefied by vibration may be made of calcium carbonate powder, water, and a fluidizing material .

According to the first invention, a seismic isolation layer that does not require a special seismic isolation device is provided in the ground for all or part of a site such as a tank yard or a plant yard, and seismic waves from the outside are transmitted. It is possible to provide a seismic isolation structure that forms difficult ground blocks.

According to a second aspect of the present invention , the ground is excavated in a substantially horizontal direction through a continuous wall of the shaft from a predetermined depth in a groove-like shaft disposed at at least one end of the ground in the area where seismic isolation is performed. A seismic isolation layer filled with a seismic isolation material composed of an aggregate of spherical particles that slide together due to vibration when an earthquake occurs, and the seismic isolation layer is formed at the end of the excavation hole. The base isolation structure is formed by sealing the base isolation material in the excavation hole with mortar filled in a portion .

A partition with a pipe roof is provided at the upper part of the seismic isolation layer so that the seismic isolation material and the upper ground of the seismic isolation layer are not mixed by the vibration to prevent deterioration of the function of the seismic isolation layer. It may be a thing . In addition, the spherical particles that slide with each other by vibration may be made of glass or stainless steel .

According to the second aspect of the invention, the seismic isolation layer that does not require a special seismic isolation device is provided in the ground for the whole or part of the site such as a tank yard or a plant yard, and the seismic waves from the outside are transmitted. It is possible to provide a seismic isolation structure that forms difficult ground blocks.

According to the present invention, the ground that is intended for the whole or part of the site such as a tank yard or a plant yard, is provided with a seismic isolation layer that does not require a special seismic isolation device or the like, and is difficult to transmit seismic waves from the outside. It is possible to provide a seismic isolation structure that forms a block and a construction method of the seismic isolation structure.

Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a flowchart showing a process of constructing a seismic isolation layer according to the present embodiment.

First, a grooved shaft is provided at the end of an area where seismic isolation is performed (step 101). FIG. 2 is a view in which a vertical shaft 5 is provided at an end of a tank yard where a plurality of tanks 1 are installed as a seismic isolation area. The shaft 5 having the continuous wall 7 is provided in a groove shape below the ground 3 at the end of the tank yard. In FIG. 2, the shaft 5 is provided at two locations so as to face each other, but only one of them may be provided, or may be provided at four locations so as to surround the tank yard. The continuous wall 7 can be, for example, a soil cement underground continuous wall.

Next, the ground 11 is excavated from the vertical shaft 5 with an excavator that is propelled from behind the pipe (step 102). FIG. 3 is a view showing a method for excavating the ground 11 from the vertical shaft 5.

First, a portion of the soil cement of the continuous wall 7 of the shaft 5 is suspended to expose the core material 9 of the continuous wall 7, and the water stopping agent is applied to the ground 11 on the back side of the continuous wall 7 at the site to be excavated. Note 12 is performed (FIG. 3A).

Next, the core material 9 of the portion to be excavated is cut, and a mortar 17 is placed in the portion. Thereafter, the sheath tube 13 having a flange is joined to the core member 9 corresponding to the excavation site by welding or the like (FIG. 3B). The sheath tube 13 is a cylindrical member having a shape suitable for guiding an excavator to be described later, and a water stop brush 15 is provided on the inner surface in the circumferential direction to prevent leakage of groundwater to the outside during excavation. It has been. Although the material of the sheath tube 13 is not ask | required, steel materials can be used, for example.

Next, the excavator 19 is installed in the sheath tube 13 (FIG. 3C).

Next, as in the ordinary pipe roof construction method, the pipe 21 is propelled forward (in the direction A in FIG. 3 (d)) with a hydraulic jack or the like while sequentially connecting the pipe 21 to the rear of the excavator 19. The ground 11 is excavated and an excavation hole 25 is provided (FIG. 3D).

The pipe 21 has an external shape that matches the excavation shape of the excavator 19, and the inside of the pipe 21 is connected to the outside for the discharge of excavated earth and sand and the addition of a mud material. One end of a PC steel wire, which will be described later, is attached to the inner surface of the pipe 21 joined to the excavator 19, and the other end of the PC steel wire is led out to the outside. The pipes 21 may be joined together by screws or the like provided in advance, or may be joined by welding. In addition, although the material of the pipe 21 is not ask | required, a steel pipe can be used, for example.

FIG. 4 is a diagram showing a method for constructing the seismic isolation layer 31. When the excavation hole 25 reaches a predetermined length, next, the seismic isolation material 25 is filled into the excavation hole 25 from the tip of the excavator 19 while the excavator 19 is pulled back (step 103). FIG. 4A is a view showing a process of filling the excavation hole 25 with the seismic isolation material 23 while pulling back the excavator 19.

As described above, the PC steel wire is connected to the inner surface of the pipe 21 connected to the excavator 19, and is connected to the outside. By pulling the PC steel wire 27 while winding it from the shaft 5, the excavator 19 is pulled backward (direction A in the figure).

In the shaft 5, the drawn pipe 21 is divided by sequential cutting or the like, and the excavator 19 and the pipe 21 are pulled out rearward. The seismic isolation material 23 is injected from the tip of the excavator 19 by injecting the seismic isolation material 23 instead of the mud material, for example, by using a pipe for injecting the mud material connected to the excavator 19. The seismic isolation material 23 can be filled.

Here, the seismic isolation material 23 in this Embodiment uses the material which is easy to liquefy by vibrations, such as an earthquake. For example, a liquefied material composed of calcium carbonate powder, water and a fluidizing agent can be used. The liquefied material has fluidity at the time of filling, but the fluidity disappears after the construction, and has the same properties as the tight gravel.

Next, the excavator 19 is pulled out and the seismic isolation material 23 is enclosed (step 104). FIG. 4B is a diagram illustrating a state where the excavator 19 is pulled out to the outer surface of the core material 9. The seismic isolation material 23 is filled in the excavation hole 25 while the excavator 19 is pulled out, but the seismic isolation material 23 is replaced by the mortar 29 by replacing the seismic isolation material 23 with the mortar 29 in the vicinity of the water-stopping chemical injection 12. It is sealed in the excavation hole 25.

When the mortar 29 is cured, the seismic isolation material 23 may be filled again between the mortar 29 and the excavator 19 in order to avoid the excavator 19 and the mortar 29 from being fixed.

FIG. 4C is a diagram showing a state where the excavator 19 and the sheath tube 13 are removed and the seismic isolation material 23 is completely filled. The seismic isolation layer can be obtained by repeatedly arranging the excavation hole 25 filled with the seismic isolation material 23 described above in the horizontal direction from the shaft 5 (step 105).

FIG. 5 is a conceptual diagram showing the seismic isolation layer 31 provided in the ground. FIG. 5A shows a case where the cross section of the excavation hole 25 is a round hole, and FIG. It is a figure which shows the case where is a rectangle.

Here, the excavation hole 25 may not be continuous as shown in FIG. For example, in FIG. 5 (a), every other excavation hole 25 may be separated and each excavation hole 25 may be separated from the adjacent excavation hole 25. In addition, in order to construct the continuous seismic isolation layer 31 as shown in FIG. 5, the construction of the individual excavation holes 25 is performed every other piece, and then the excavation holes 25 are constructed so as to fill in between them. It is desirable because there are few bends. Further, the excavation holes 25 may be provided one by one, or a plurality of excavation holes 25 may be provided at a time.

FIG. 6 is a diagram illustrating a state where the seismic isolation layer 31 is provided in the tank area. In this Embodiment, although two places are provided so that the shaft 5 may face, the seismic isolation layer 31 can be constructed from each shaft 5 in this case. The seismic isolation layer 31 provided from each shaft 5 may be joined at an arbitrary position between the shafts 5, for example, at substantially the center, or may not be completely connected. In addition, what is necessary is just to provide the seismic isolation layer 31 from one side when the shaft 5 is only one place.

Here, the ground above the seismic isolation layer 31 may perform ground reinforcement such as chemical injection from the shaft 5 or the ground 3 as necessary. Moreover, you may reinforce the ground by constructing underground beams above the seismic isolation layer 31 and around each tank.

In addition, since the seismic isolation material 23 with which the seismic isolation layer 31 was filled is a liquefied material, in order to acquire a seismic isolation function always, the seismic isolation layer 31 needs to be deeper than a groundwater level. This is because it does not liquefy when dehydrated.

As described above, according to the present embodiment, it is possible to obtain the seismic isolation layer 31 filled with the seismic isolation material 23 that is easily liquefied by vibration such as an earthquake. Since the seismic isolation layer 31 is liquefied by vibration such as an earthquake, the vibration from the ground 11 can be cut off and vibration transmission to a structure such as an upper tank can be prevented.

In addition, there is no need to place concrete in the seismic isolation layer 31 and it is not necessary to install a special seismic isolation structure. Excellent.

The seismic isolation layer 31 that has been liquefied once by the earthquake loses its fluidity again when the vibrations stop and has the same properties as the tight gravel, so that it is not necessary to perform construction again each time an earthquake occurs.

Next, a second embodiment will be described. In the second embodiment, the same numbers as those shown in FIGS. 1 to 6 are used for the constituent elements that perform the same functions as those in the first embodiment, and a duplicate description is avoided.

The second embodiment differs from the first embodiment only in the seismic isolation material 23 and the seismic isolation material 23 filling method. That is, the construction steps of the seismic isolation layer 31 shown in FIG. 1 are exactly the same. First, the shaft 5 is provided at the end of the area (step 101), and the excavation hole 25 is provided in the ground from the shaft 5 (step 102).

Next, while the excavator 19 is pulled back, the seismic isolation material 23 is filled into the excavation hole 25 (step 103), and the seismic isolation material is enclosed (step 104). In the present embodiment, an aggregate of spherical particles is filled as the seismic isolation material 23 (FIG. 4A). Spherical particles are rigid, rust-resistant members such as glass or stainless steel, and cause slippage or rotational movement like a bearing due to vibration caused by an earthquake. For this reason, it is desirable that the spherical particle surfaces be smooth, and it is desirable that the spherical particles have approximately the same size. Moreover, since there exists a problem in workability when the size of a spherical particle is too large, about 0.1-10 mm in diameter is desirable, for example.

In the second embodiment, the seismic isolation material 23 is filled using, for example, a screw conveyor installed separately from the pipe for injecting the mud material.

According to the second embodiment, the same effects as in the first embodiment can be obtained. That is, the seismic isolation layer 31 filled with the seismic isolation material 23 can be obtained. The seismic isolation layer 31 shuts off vibrations from the ground 11 by sliding spherical particles inside each other due to vibrations such as earthquakes, or by rotating like a bearing, to a structure such as an upper tank. Vibration transmission can be prevented.

Moreover, since the liquefaction phenomenon by vibration is not used, the construction depth of the seismic isolation layer 31 is irrelevant to the groundwater level as described above. That is, since the seismic isolation layer 31 according to the present embodiment can obtain an effect even in an area where the groundwater level is deep, a construction area is not selected and the seismic isolation layer 31 has a high degree of freedom.

Next, a third embodiment will be described. In the following description, components having the same functions as those of the first embodiment are denoted by the same numbers as those shown in FIGS. 1 to 6, and a duplicate description is avoided. In addition, as the seismic isolation material 23, any of the liquefied material according to the first embodiment and the aggregate of spherical particles according to the second embodiment may be used, but in the following description, A case where a liquefied material is used will be described.

In the third embodiment, steps 101 to 105 in FIG. 1 are the same. That is, the base isolation layer 31 filled with the base isolation material 23 is constructed. Next, a pipe roof is newly constructed on the constructed seismic isolation layer 31.

FIG. 7 is a conceptual diagram showing a cross section of the seismic isolation layer 31 and the pipe roof 33 in the ground. The pipe roof 33 is constructed by a general method. That is, steps 101 to 102 are repeated in the width direction.

The pipe used in the pipe roof 33 may be a square pipe as shown in FIG. 7 or a round pipe. Moreover, in order to obtain the strength of the pipe roof 33, it is desirable to join adjacent pipes.

FIG. 8 is a view showing a state in which the pipe roof 33 is provided on the upper part of the seismic isolation layer 31 provided in the tank area. In the present embodiment, two places are provided so as to face the shaft 5, but in this case, the pipe roof 33 can be constructed from each shaft 5 as in the construction of the seismic isolation layer 31. The pipe roof 33 provided from each shaft 5 may be joined at an arbitrary position between the shafts 5, for example, at substantially the center, or may not be completely connected. In addition, what is necessary is just to provide the pipe roof 33 from one side, when the shaft 5 is only one place.

According to the third embodiment, there are the same effects as in the first embodiment. That is, the seismic isolation layer 31 filled with the seismic isolation material 23 that is easily liquefied by vibration such as an earthquake can be obtained. Since the seismic isolation layer 31 is liquefied by vibration such as an earthquake, the vibration from the ground 11 can be cut off and vibration transmission to a structure such as an upper tank can be prevented.

Further, since the pipe roof 33 is provided above the seismic isolation layer 31, the seismic isolation material 23 in the seismic isolation layer 31 and the ground 11 above the seismic isolation layer 31 are not mixed with each other due to vibration such as an earthquake. It is possible to prevent the function of the layer 31 from deteriorating. Furthermore, the ground 11 above the seismic isolation layer 31 can be strengthened.

Next, a fourth embodiment will be described. In the fourth embodiment, steps 101 to 105 in FIG. 1 are the same. That is, the base isolation layer 31 filled with the base isolation material 23 is constructed. Next, the seismic isolation material 23 is filled in the part where the shaft 5 was provided.

FIG. 9 is a diagram showing a state in which the seismic isolation material filling portion 35 filled with the seismic isolation material 23 is provided in the shaft 5. In FIG. 9, two seismic isolation material filling portions 35 are provided so as to face each other, but only one of them may be provided. That is, it is not necessary for all the installed shafts 5 to be the seismic isolation material filling portion 35, and a part of the shaft 5 may be left, and in this case, the shaft 5 may be watered. Further, when the tank yard is surrounded by the shaft 5, the seismic isolation material filling portion 35 can be provided so as to surround the tank yard.

When filling the shaft 5 with the seismic isolation material 23, the continuous wall 7 or the like may be left. However, in order to further enhance the seismic isolation effect, it is desirable to fill the seismic isolation material 23 after removing the concrete portion such as the continuous wall 7 in the shaft 5 as shown in FIG. In this case, transmission of vibrations by a structure such as concrete can be eliminated, and the seismic isolation material 23 can effectively block transmission of vibrations from the outside.

According to the fourth embodiment, there are the same effects as in the first embodiment. That is, the seismic isolation layer 31 filled with the seismic isolation material 23 that is easily liquefied by vibration such as an earthquake can be obtained. Since the seismic isolation layer 31 is liquefied by vibration such as an earthquake, the vibration from the ground 11 can be cut off and vibration transmission to a structure such as an upper tank can be prevented.

Further, since the seismic isolation material filling portion 35 is also provided in the circumferential direction of the seismic isolation area ground, the seismic isolation material filling portion 35 at a position deeper than the groundwater surface is liquefied even with respect to vibration from the side, and the ground Vibration transmission to structures such as the upper tank can be prevented. For this reason, a higher seismic isolation effect can be obtained.

Next, a fifth embodiment will be described. In the fifth embodiment, the seismic isolation layer 31 is directly constructed without providing the shaft 5. FIG. 10 is a diagram illustrating the seismic isolation layer 31 according to the fifth embodiment.

The construction method of the seismic isolation layer 31 is substantially the same as steps 102 to 104 in FIG. 1, but the excavation hole 25 is constructed from the ground 3 in step 102. That is, it is not necessary to provide the shaft 5 in the construction of the seismic isolation layer 31 according to the fifth embodiment.

The excavation method is the same as the method shown in FIG. 3D, and the excavator 19 performs excavation while drawing a predetermined curve from the rear by the thrust of the hydraulic jack and the pipe 21. When the excavation is completed to a predetermined position, the excavator 19 is pulled back while filling the excavation hole 25 with the seismic isolation material 23 in the same manner as in step 103, and the seismic isolation material 23 is enclosed (step 104).

The seismic isolation layer 31 according to the fifth embodiment is preferably constructed from both sides of the seismic isolation area. In this case, the seismic isolation layer 31 may be joined at an arbitrary position between the respective construction start positions, for example, substantially at the center, or may not be completely connected. Moreover, you may provide the seismic isolation layer 31 from one side.

According to the fifth embodiment, there are the same effects as in the first embodiment. That is, the seismic isolation layer 31 filled with the seismic isolation material 23 that is easily liquefied by vibration such as an earthquake can be obtained. Since the seismic isolation layer 31 is liquefied by vibration such as an earthquake, the vibration from the ground 11 can be cut off and vibration transmission to a structure such as an upper tank can be prevented.

Moreover, in the construction of the seismic isolation layer 31, it is not necessary to provide the shaft 5 in advance, and only the construction from the ground is performed, so the construction is easy. In addition, after the seismic isolation layer 31 is constructed, the seismic isolation layer 31 can efficiently block vibration transmission from the ground circumference direction without providing the seismic isolation material filling portion 35 separately.

As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

For example, the seismic isolation layer 31 and the seismic isolation material filling unit 35 may be filled with different seismic isolation materials. In the third embodiment, the pipe roof 33 may be provided not only in the upper part of the seismic isolation layer 31 but also in the lower part. In this case, the seismic isolation layer 31 and the ground below the seismic isolation layer 31 are unlikely to be mixed, and deterioration of the seismic isolation layer 31 can be prevented. Further, in the curved seismic isolation layer 31 according to the fifth embodiment, a pipe roof 33 may be further provided above the seismic isolation layer 31. In addition, the seismic isolation layer 31 concerning this invention is not restricted to application to a tank yard, It is applicable also to any area of the fixed range which requires a seismic isolation.

The flowchart which showed the process of constructing the seismic isolation layer concerning this Embodiment. The figure which provided the shaft 5 in the edge part of the tank yard in which the some tank 1 was installed as a seismic isolation area. It is the figure which showed the method of excavating the ground 11 from the vertical shaft 5, (a) has exposed the core material 9 of the continuous wall 7, and decided the state which performed the water-stopping chemical injection 12 to the back side of the continuous wall 7 (B) is a figure which shows the state which joined the sheath pipe 13 to the core material 9 by welding etc., (c) is a figure which shows the state which installed the excavator 19 in the sheath pipe 13, (d) is the ground The figure which shows the state which excavated 11 and provided the excavation hole 25. FIG. It is the figure which showed the method of constructing the seismic isolation layer, (a) is the figure which shows the process of filling the seismic isolation material 23 in the excavation hole 25, pulling back the excavator 19, (b) The figure which shows the state pulled out to the outer surface of the core material 9, (c) is the figure which removes the excavator 19 and the sheath tube 13, and shows the state which the filling of the seismic isolation material 23 was completed. It is the conceptual diagram which showed the seismic isolation layer 31 provided in the ground, (a) is a figure which shows the case where the excavation hole 25 cross section is a round hole, (b) is the figure which shows the case where the excavation hole 25 cross section is a rectangle. . The figure which shows the state in which the seismic isolation layer 31 was provided in the tank area. The conceptual diagram which shows the cross section of the seismic isolation layer 31 and the pipe roof 33 in the ground. The figure which shows the state by which the pipe roof 33 was provided in the upper part of the seismic isolation layer 31 provided in the tank area. The figure which shows the state in which the seismic isolation material filling part 35 with which the seismic isolation material 23 was filled was provided in the site | part of the shaft 5. The figure which shows the seismic isolation layer 31 concerning 5th Embodiment.

Explanation of symbols

1 ......... Tank 3 ......... Ground 5 ......... Vertical shaft 7 ......... Continuous wall 11 ......... Ground 12 ......... Water-stopping chemical injection 13 ......... Sheath tube 15 ......... Water-stop brush 17 ... ... Mortar 19 ......... Excavator 21 ......... Pipe 23 ......... Seismic isolation material 25 ......... Drilling hole 27 ......... PC steel wire 29 ......... Mortar 31 ......... Seismic isolation layer 33 ......... Pipe Roof 35 ………… Seismic isolation material filling section

Claims (5)

An excavation hole provided by excavating the ground in a substantially horizontal direction through a continuous wall of the vertical shaft from a predetermined depth in a groove-shaped vertical shaft disposed at at least one end of the ground in an area where seismic isolation is performed The seismic isolation layer is filled with a seismic isolation material that liquefies due to vibration when an earthquake occurs, and the seismic isolation layer is formed of mortar filled at the end of the excavation hole so that the seismic isolation material is Seismic isolation structure characterized by being formed by being enclosed in a borehole . An excavation hole provided by excavating the ground in a substantially horizontal direction through a continuous wall of the vertical shaft from a predetermined depth in a groove-shaped vertical shaft disposed at at least one end of the ground in an area where seismic isolation is performed A seismic isolation layer filled with a seismic isolation material composed of an assembly of spherical particles that slide together due to vibration when an earthquake occurs, and the seismic isolation layer is a mortar filled at the end of the excavation hole Thus, the base isolation structure is formed by sealing the base isolation material in the excavation hole . A partition with a pipe roof is provided at the upper part of the seismic isolation layer so that the seismic isolation material and the upper ground of the seismic isolation layer are not mixed by the vibration to prevent deterioration of the function of the seismic isolation layer. The seismic isolation structure according to claim 1 or claim 2, wherein The seismic isolation structure according to claim 1, wherein the seismic isolation material liquefied by the vibration is composed of calcium carbonate powder, water, and a fluidizing material . The seismic isolation structure according to claim 2, wherein the spherical particles that slide with each other due to the vibration are made of glass or stainless steel .

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