Floating-type base isolation system

Abstract

A floating body type base isolation system 100 comprises: a liquid storage part 110 that stores liquid in a storage space S demarcated by an inner wall 120a of a wall part 120; and a floating body type structure 130 that is disposed by floating in the liquid stored in the storage space S of the liquid storage part 110. An area (first inclined surface P1) inclined with respect to an outer surface 134 of the floating body type structure 130 is provided on the inner wall 120a of the wall part 120 of the liquid storage part 110.

Description

Floating seismic isolation system

[0001] This disclosure relates to a floating seismic isolation system. This application claims the benefit of priority from Japanese Patent Application No. 2023-192748, filed on November 13, 2023, the contents of which are incorporated herein by reference.

[0002] Floating seismic isolation systems that use liquid have been developed. For example, Patent Document 1 discloses a floating seismic isolation system in which liquid is stored in a rectangular parallelepiped storage space formed in a tank, and a floating structure is floated in the liquid.

[0003] In the technology of Patent Document 1, the floating structure is composed of multiple rod-shaped members extending horizontally and includes a float placed in liquid, a foundation placed on the float, and a building placed on the foundation.

[0004] JP 2009-114659 A

[0005] However, in the technology disclosed in Patent Document 1, in which the inner wall of the tank and the side wall of the float are arranged parallel to each other, the distance between the tank and the side wall of the float is equal along the entire side wall of the float. In this case, the arrival time of earthquake waves propagating from the inner wall of the tank to the side wall of the float is equal along the entire side wall of the float. This causes the floating structure to vibrate significantly in the event of an earthquake.

[0006] In view of these problems, the present disclosure aims to provide a floating seismic isolation system that can suppress vibrations of floating structures caused by earthquakes.

[0007] In order to solve the above problems, a floating seismic isolation system according to one embodiment of the present disclosure comprises a liquid storage section that stores liquid in a storage space partitioned by the inner wall of a wall section, and a floating structure that is placed floating on the liquid stored in the storage space of the liquid storage section, and the inner wall of the wall section of the liquid storage section has an area that is inclined with respect to the outer surface of the floating structure.

[0008] Furthermore, the area of ​​the region parallel to the outer surface of the floating structure on the inner wall of the wall portion of the liquid storage section may be smaller than the area of ​​the region not parallel to the outer surface of the floating structure.

[0009] In addition, the wall of the liquid storage section may have a side wall section, the outer surface of the floating structure may have a side surface extending in a vertical or approximately vertical direction, and the inner wall of the side wall section may have a first inclined surface that slopes from below to above in a direction away from the side surface of the floating structure.

[0010] The inner wall of the side wall portion may have a second inclined surface that slopes upward from below in a direction approaching the side surface of the floating structure.

[0011] The inner wall of the wall portion of the liquid storage portion may be provided with a plurality of spindle-shaped protrusions.

[0012] Furthermore, the inner wall of the wall portion of the liquid storage portion and the protrusion portion may be separate bodies.

[0013] According to the present disclosure, it is possible to suppress vibrations of floating structures caused by earthquakes.

[0014] Fig. 1 is a diagram illustrating a floating-body seismic isolation system according to a first embodiment. Fig. 2 is a diagram illustrating a liquid storage section according to a first modified example. Fig. 3 is a diagram illustrating a liquid storage section according to a second modified example. Fig. 4 is a diagram illustrating a floating-body seismic isolation system according to a second embodiment.

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation. Elements not directly related to the present disclosure are not shown.

[0016] [First embodiment: floating-body seismic isolation system 100] Fig. 1 is a diagram illustrating a floating-body seismic isolation system 100 according to a first embodiment. As shown in Fig. 1, the floating-body seismic isolation system 100 according to the first embodiment includes a liquid storage section 110, a floating structure 130, and a mooring section 140. Note that in the following figures, including Fig. 1, cross-hatching represents liquid.

[0017] The liquid storage section 110 is provided, for example, in a depression or hole formed by digging the ground 10. The liquid storage section 110 has a wall section 120. The liquid storage section 110 stores liquid in a storage space S defined by an inner wall 120a of the wall section 120. The wall section 120 has, for example, a side wall section 122 and a bottom wall section 124. The side wall section 122 is a wall that stands upright from the bottom wall section 124. The bottom wall section 124 is a wall that extends horizontally or approximately horizontally. In this embodiment, the storage space S is defined by the inner wall 122a of the side wall section 122 and the inner wall 124a of the bottom wall section 124. In other words, the side surface of the storage space S is formed by the inner wall 122a of the side wall section 122. Furthermore, the bottom surface of the storage space S is formed by the inner wall 124a of the bottom wall section 124.

[0018] The liquid stored in the liquid storage unit 110 is, for example, water. However, the liquid is not limited to this and may be any liquid other than water, or may be another liquid containing water as a main component (for example, seawater).

[0019] The floating structure 130 is disposed so as to float in the liquid stored in the storage space S of the liquid storage section 110. The floating structure 130 is disposed at a distance from the inner wall 120a of the wall section 120 of the liquid storage section 110 (e.g., the inner wall 122a of the side wall section 122 and the inner wall 124a of the bottom wall section 124). The floating structure 130 is, for example, a floating nuclear power plant. However, the floating structure 130 is not limited thereto, and may be a structure for other plants such as a wind power plant, a wave power plant, or a solar power plant, or may be any other structure on which any equipment is mounted.

[0020] The floating structure 130 is provided with one or more gas storage sections 132. A gas is stored in the gas storage section 132. The gas storage section 132 is provided, for example, on the bottom surface 134a of the outer surface 134 of the floating structure 130. The gas stored in the gas storage section 132 comes into contact with the liquid stored in the liquid storage section 110. The gas stored in the gas storage section 132 is, for example, air or nitrogen.

[0021] The volume of the gas storage section 132 is set based on the natural frequency of a system that responds to seismic waves propagating through a fluid containing liquid and gas. The volume of the gas storage section 132 is set, for example, so that the natural frequency of the system that responds to seismic waves is smaller than the natural frequency of the floating structure 130 and the equipment mounted on the floating structure 130. Furthermore, the volume of the gas storage section 132 is set, for example, so that the natural frequency of the system that responds to seismic waves is less than 1 Hz.

[0022] The mooring portion 140 is a column extending horizontally or approximately horizontally. The mooring portion 140 is, for example, a circular column or a rectangular column. One end of the mooring portion 140 is fixed to the side surface 134b of the outer surface 134 of the floating structure 130. The other end of the mooring portion 140 is fixed to the inner wall 122a of the side wall portion 122 of the liquid storage portion 110.

[0023] The mooring section 140 is made of a material that does not undergo plastic deformation (e.g., buckling deformation) when a load less than a predetermined seismic intensity is applied, but undergoes plastic deformation when a load equal to or greater than the predetermined seismic intensity is applied. The mooring section 140 may also be made of a material that undergoes compressive failure when a load equal to or greater than the predetermined seismic intensity is applied. The predetermined seismic intensity is set depending on the floating structure 130 and the equipment installed thereon.

[0024] [Relationship Between Inner Wall 120a of Liquid Storage Section 110 and Outer Surface 134 of Floating Structure 130] Next, the relationship between the inner wall 120a of the liquid storage section 110 and the outer surface 134 of the floating structure 130 will be described.

[0025] The inner wall 120 a of the wall portion 120 of the liquid storage portion 110 has an area that is inclined with respect to the outer surface 134 of the floating structure 130 .

[0026] Specifically, in this embodiment, the floating structure 130 is, for example, a rectangular parallelepiped. Therefore, the outer surface 134 of the floating structure 130 has a bottom surface 134a and four side surfaces 134b. The four side surfaces 134b of the floating structure 130 extend, for example, vertically or approximately vertically.

[0027] Furthermore, in this embodiment, the storage space S of the liquid storage portion 110 is, for example, a truncated quadrangular pyramid with the top surface larger than the bottom surface. That is, in this embodiment, the four inner walls 122a of the side wall portion 122 of the liquid storage portion 110 are configured with first inclined surfaces P1. The four first inclined surfaces P1 respectively face the four side surfaces 134b of the floating structure 130. The first inclined surfaces P1 are inclined from below to above in a direction away from the side surfaces 134b of the floating structure 130. Furthermore, the first inclined surfaces P1 are inclined from below to above in a direction expanding outward from the liquid storage portion 110.

[0028] The inclination angle θ of the first inclined surface P1 from the horizontal plane is, for example, not less than 10° and less than 75°, and preferably not less than 10° and less than 45°.

[0029] In this embodiment, the bottom surface 134a of the outer surface 134 of the floating structure 130 extends, for example, horizontally or approximately horizontally. Also, in this embodiment, the inner wall 124a of the bottom wall portion 124 of the liquid storage section 110 extends, for example, horizontally or approximately horizontally.

[0030] As described above, in the floating seismic isolation system 100 according to this embodiment, the side surface 134b of the floating structure 130 extends in the vertical direction or a substantially vertical direction, and the inner wall 122a (inner surface) of the side wall 122 of the liquid storage portion 110 is configured as the first inclined surface P1. This makes it possible to reduce the area of ​​the region on the inner wall 122a of the side wall 122 of the liquid storage portion 110 that is parallel to the side surface 134b of the floating structure 130 to substantially zero. Therefore, compared to when the inner wall 122a of the side wall 122 is parallel to the side surface 134b of the floating structure 130, it is possible to increase the region on the side surface 134b of the floating structure 130 where the distance from the inner wall 122a of the side wall 122 of the liquid storage portion 110 is different. That is, it is possible to increase the area on the side surface 134b of the floating structure 130 where the arrival times of earthquake waves (pressure waves) propagating from the inner wall 122a of the side wall portion 122 of the liquid storage portion 110 are different. Therefore, the floating seismic isolation system 100 according to this embodiment can reduce earthquake waves that simultaneously arrive at the side surface 134b of the floating structure 130, and can suppress vibration of the floating structure 130 due to an earthquake.

[0031] Furthermore, an earthquake can cause the direction of waves propagating from the first inclined surface P1 of the side wall 122 of the liquid storage section 110 to the liquid to differ from the normal direction of the side surface 134b of the floating structure 130. Therefore, the floating seismic isolation system 100 according to this embodiment can suppress the propagation of waves from the liquid to the floating structure 130, and can suppress vibration of the floating structure 130 due to an earthquake.

[0032] Furthermore, as described above, the first inclined surface P1 of the side wall 122 of the liquid storage portion 110 is inclined from bottom to top in a direction widening outward from the liquid storage portion 110. Therefore, the area of ​​the liquid surface (open surface) of the liquid storage portion 110 can be made larger compared to when the inner wall 122a of the side wall 122 is parallel to the side surface 134b of the floating structure 130. This allows the liquid storage portion 110 to expand the space in which the liquid can move at the liquid surface, making it possible to further suppress the propagation of waves caused by an earthquake to the floating structure 130 via the liquid stored in the liquid storage portion 110.

[0033] As described above, the floating structure 130 includes a gas storage section 132 provided on the bottom surface 134a. The volume of the gas storage section 132 is set based on the natural frequency of the system that responds to seismic waves propagating through a fluid containing liquid and gas. This makes it possible to reduce excitation of the floating structure 130 and its onboard equipment due to earthquakes.

[0034] Furthermore, as described above, the floating seismic isolation system 100 includes the mooring section 140. Therefore, when no earthquake occurs or when an earthquake of less than a predetermined seismic intensity occurs, it is possible to prevent the floating structure 130 from moving horizontally due to wind or the like. Furthermore, as described above, when an earthquake of a predetermined seismic intensity or higher occurs, the mooring section 140 undergoes plastic deformation or compressive failure. Therefore, when an earthquake of a predetermined seismic intensity or higher occurs, it is possible to suppress the propagation of waves from the side wall section 122 to the floating structure 130.

[0035] [First Modification] In the above-described first embodiment, an example was given in which the inner wall 122a of the side wall 122 of the liquid storage section 110 is configured only by the first inclined surface P1. However, the inner wall of the side wall of the liquid storage section may include an inclined surface whose inclination direction with respect to the side surface 134b of the floating structure 130 is different from that of the first inclined surface P1.

[0036] 2 is a diagram illustrating a liquid storage section 210 according to the first modified example. Note that components that are substantially the same as those in the floating-body seismic isolation system 100 described above are given the same reference numerals and descriptions thereof will be omitted.

[0037] 2 , the wall 220 of the liquid storage section 210 according to the first modification has a side wall 222 and a bottom wall 124. In the first modification, the inner wall 222a of the side wall 222 has a second inclined surface P2 in addition to a first inclined surface P1. The second inclined surface P2 slopes upward from below in a direction approaching the side surface 134b of the floating structure 130.

[0038] In the first modified example as well, the area of ​​the region parallel to the side surface 134b of the floating structure 130 on the inner wall 222a of the side wall portion 222 of the liquid storage section 210 can be made substantially zero.

[0039] 2, in the first modified example, it is preferable that the uppermost region of the inner wall 222a of the side wall portion 222 of the liquid storage portion 210 is made into the first inclined surface P1. This makes it possible to increase the area of ​​the liquid surface (open surface) of the liquid storage portion 210.

[0040] [Second Modification] In the above-described first embodiment, the inner wall 122a of the side wall 122 of the liquid storage portion 110 is configured only by the first inclined surface P1. However, the inner wall 322a of the side wall 322 of the liquid storage portion 310 may include a surface other than the first inclined surface P1.

[0041] 3 is a diagram illustrating a liquid storage section 310 according to the second modified example. Note that components that are substantially the same as those in the floating-type seismic isolation system 100 described above are given the same reference numerals and descriptions thereof will be omitted.

[0042] As shown in Fig. 3, the wall 320 of the liquid storage section 310 according to the second modification has a side wall 322 and a bottom wall 124. In the second modification, the region of the inner wall 322a of the side wall 322 that faces the side surface 134b of the floating structure 130 is a first inclined plane P1, and the region that does not face the side surface 134b of the floating structure 130 is a vertical plane P3. The vertical plane P3 extends in the vertical direction or a substantially vertical direction. The angle formed between the vertical plane P3 and the inner wall 124a of the bottom wall 124 is, for example, 90°.

[0043] In the second modified example as well, the area of ​​the region parallel to the side surface 134b of the floating structure 130 on the inner wall 322a of the side wall portion 322 of the liquid storage section 310 can be made substantially zero.

[0044] Second Embodiment In the first embodiment, the inner wall 122a of the side wall 122 of the liquid storage section 110 is configured with the first inclined surface P1. However, it is only necessary that the area of ​​the region of the inner wall of the wall of the liquid storage section that is parallel to the outer surface 134 of the floating structure 130 is smaller than the area of ​​the region that is not parallel to the outer surface 134 of the floating structure 130.

[0045] Fig. 4 is a diagram illustrating a floating-body seismic isolation system 400 according to the second embodiment. As shown in Fig. 4, the floating-body seismic isolation system 400 according to the second embodiment includes a liquid storage section 410, a floating structure 130, and a mooring section 140. Note that components that are substantially the same as those in the floating-body seismic isolation system 100 described above are given the same reference numerals, and descriptions thereof will be omitted.

[0046] The liquid storage section 410 according to this embodiment includes a wall section 420. The wall section 420 has a side wall section 422 and a bottom wall section 124.

[0047] In this embodiment, the inner wall 422a of the side wall portion 422 extends vertically or approximately vertically. The inner wall 422a of the side wall portion 422 is parallel or approximately parallel to the side surface 134b of the floating structure 130. In other words, the storage space S defined by the inner wall 420a of the wall portion 420 of the liquid storage portion 410 according to this embodiment is, for example, a rectangular parallelepiped or approximately rectangular parallelepiped.

[0048] In this embodiment, a plurality of protrusions 430 are provided on the inner wall 422a of the side wall portion 422. The protrusions 430 protrude from the inner wall 422a of the side wall portion 422. The protrusions 430 are pyramidal. For example, the protrusions 430 are pyramidal, such as triangular, quadrangular, pentagonal, or hexagonal, or conical. Therefore, the surface of the protrusions 430 is inclined with respect to the side surface 134b of the floating structure 130. The surface of the protrusions 430 forms the inner surface of the side wall portion 422.

[0049] The multiple protrusions 430 are provided without gaps, for example, on at least the area of ​​the inner wall 422 a of the side wall portion 422 that faces the side surface 134 b of the floating structure 130 .

[0050] The protrusion 430 is, for example, separate from the inner wall 422a. Here, "separate" means that the inner wall 422a and the protrusion 430 are formed separately, and does not necessarily mean that the inner wall 422a and the protrusion 430 are separable. For example, the protrusion 430 may be formed separately from the inner wall 422a and then attached to the inner wall 422a by a known method such as adhesive bonding, screwing, or fastening. Furthermore, the multiple protrusions 430 do not necessarily have to be separate from each other. For example, the bases of the multiple protrusions 430 may be formed integrally with a flat plate, and the flat plate and the inner wall 422a may be attached by a known method such as adhesive bonding, screwing, or fastening. Furthermore, the inner wall 422a and the protrusion 430 may be made of different materials. For example, the inner wall 422a may be formed of a highly rigid material such as concrete, and the protrusion 430 may be formed of a flexible material such as urethane foam.

[0051] As described above, in the floating seismic isolation system 400 according to this embodiment, the inner wall 422a of the side wall 422 of the liquid storage portion 410 is provided with a plurality of protrusions 430 having a surface that is inclined with respect to the side surface 134b of the floating structure 130. This makes it possible to substantially eliminate the area of ​​the region parallel to the side surface 134b of the floating structure 130 in the region of the inner wall 422a of the side wall 422 of the liquid storage portion 410 that is provided with the plurality of protrusions 430. Therefore, compared to when the inner wall 422a of the side wall 422 of the liquid storage portion 410 does not have the protrusions 430, it is possible to increase the region in the side surface 134b of the floating structure 130 where the distance from the inner surface of the side wall 422 of the liquid storage portion 410 is different. That is, it is possible to increase the area on the side surface 134b of the floating structure 130 where the arrival times of earthquake waves propagating from the inner surface of the side wall portion 422 of the liquid storage portion 410 are different. Therefore, the floating seismic isolation system 400 according to this embodiment can reduce earthquake waves that simultaneously arrive at the side surface 134b of the floating structure 130, and can suppress vibration of the floating structure 130 due to an earthquake.

[0052] Furthermore, an earthquake can cause the direction of waves propagating from the surface of the protruding portion 430 of the side wall portion 422 of the liquid storage portion 410 to the liquid to differ from the normal direction of the side surface 134b of the floating structure 130. Therefore, the floating seismic isolation system 400 according to this embodiment can suppress the propagation of waves from the liquid to the floating structure 130, and can suppress vibration of the floating structure 130 due to an earthquake.

[0053] As described above, the protrusion 430 is separate from the inner wall 422a of the side wall 422. This allows the protrusion 430 to be easily installed on the inner wall 422a.

[0054] Furthermore, the floating-body seismic isolation system 400 according to the second embodiment can reduce the volume of the storage space S of the liquid storage section 410 compared to the floating-body seismic isolation system 100 according to the first embodiment. This makes it possible to reduce the installation area of ​​the floating-body seismic isolation system 400.

[0055] Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0056] For example, in the first embodiment and the first modified example described above, the wall portions 120, 220 include the side wall portions 122, 222 and the bottom wall portion 124. However, the wall portions 120, 220 do not need to include the bottom wall portion 124. For example, the wall portion 120 may include only the side wall portion 122 configured with the first inclined surface P1. In this case, the bottom surface 134a of the floating structure 130 faces the first inclined surface P1. Similarly, the wall portion 220 may include only the side wall portion 222 configured with the first inclined surface P1 and the second inclined surface P2. In this case, the bottom surface 134a of the floating structure 130 faces the first inclined surface P1.

[0057] Furthermore, in the first embodiment and the first and second modified examples, the side surface 134b of the floating structure 130 extends vertically or approximately vertically. However, the side surface 134b of the floating structure 130 may be inclined. In this case, the inner walls 122a, 222a, 322a of the side wall portions 122, 222, 322 of the liquid storage portions 110, 210, 310 may extend vertically or approximately vertically. In either case, it is sufficient that the inner walls 122a, 222a, 322a of the side wall portions 122, 222, 322 of the liquid storage portions 110, 210, 310 are inclined with respect to the side surface 134b of the floating structure 130.

[0058] In the second embodiment described above, the case where the multiple protrusions 430 are separate from the inner wall 422 a of the side wall 422 of the liquid storage portion 410 has been exemplified. However, the protrusions 430 may be formed integrally with the inner wall 422 a of the side wall 422 of the liquid storage portion 410.

[0059] Furthermore, in the above-described second embodiment, an example was given in which the multiple protrusions 430 are provided on at least the region of the inner wall 422a of the side wall 422 of the liquid storage portion 410 that faces the side surface 134b of the floating structure 130. However, the multiple protrusions 430 may be provided on the entire inner wall 422a of the side wall 422 of the liquid storage portion 410.

[0060] In the second embodiment, the multiple protrusions 430 are provided without any gaps on the inner wall 422a of the side wall 422 of the liquid storage section 410. However, the multiple protrusions 430 may be provided at predetermined intervals.

[0061] Furthermore, in the above-described first and second embodiments and first and second modified examples, the case where the gas storage section 132 is provided on the bottom surface 134a of the floating structure 130 has been described as an example. However, the floating structure 130 does not have to be provided with the gas storage section 132. In this case, the inner wall 124a of the bottom wall section 124 of the liquid storage section 110, 210, 310 may be provided with an inclined surface or a protrusion 430.

[0062] In the first embodiment and the first and second modified examples, a plurality of protrusions 430 may be provided on the inner wall 124 a of the bottom wall portion 124 .

[0063] Furthermore, in the above-described first and second embodiments and first and second modified examples, the floating-body seismic isolation system 100 is provided with the mooring section 140. However, the mooring section 140 is not an essential component.

[0064] P1: First inclined surface P2: Second inclined surface S: Storage space 100: Floating seismic isolation system 110: Liquid storage section 120: Wall section 120a: Inner wall 122: Side wall section 122a: Inner wall 124: Bottom wall section 124a: Inner wall 130: Floating structure 134: Outer surface 134a: Bottom surface 134b: Side surface 210: Liquid storage section 220: Wall section 222: Side wall section 222a: Inner wall 310: Liquid storage section 320: Wall section 322: Side wall section 322a: Inner wall 400: Floating seismic isolation system 410: Liquid storage section 420: Wall section 422: Side wall section 422a: Inner wall 430: Protrusion

Claims

1. A floating seismic isolation system comprising: a liquid storage section that stores liquid in a storage space partitioned by an inner wall of a wall section; and a floating structure that is arranged to be floated on the liquid stored in the storage space of the liquid storage section, wherein the inner wall of the wall section of the liquid storage section is provided with an area that is inclined with respect to the outer surface of the floating structure.

2. A floating seismic isolation system as described in claim 1, wherein the area of ​​the inner wall of the wall portion of the liquid storage section that is parallel to the outer surface of the floating structure is smaller than the area of ​​the area that is not parallel to the outer surface of the floating structure.

3. A floating seismic isolation system as described in claim 1 or 2, wherein the wall portion of the liquid storage portion has a side wall portion, the outer surface of the floating structure has a side extending in a vertical or approximately vertical direction, and the inner wall of the side wall portion has a first inclined surface that slopes from below to above in a direction away from the side of the floating structure.

4. A floating seismic isolation system as described in claim 3, wherein the inner wall of the side wall portion has a second inclined surface that slopes from bottom to top in a direction approaching the side of the floating structure.

5. A floating seismic isolation system as described in claim 1 or 2, wherein the inner wall of the wall portion of the liquid storage section has a plurality of weight-shaped protrusions.

6. A floating seismic isolation system as described in claim 5, wherein the inner wall of the wall portion of the liquid storage section and the protrusion are separate entities.