Floating seismic isolation system

Abstract

The present invention relates to a floating seismic isolation system (100), which comprises: a liquid storage portion (110) for storing liquid (114); a floating structure (120) arranged to float on the liquid (114); and a gas storage space (132) provided at a position in contact with the liquid (114) and containing the gas (134). The volume of the gas storage space (132) is set based on the natural vibration frequency of the system in response to seismic waves propagating in a fluid containing the liquid (114) and the gas (134).

Description

Technical Field

[0001] The present disclosure relates to a floating seismic isolation system. This application claims the benefit of priority based on Japanese Patent Application No. 2020-95752, filed on June 1, 2020, the contents of which are incorporated herein by reference. Background Art

[0002] Patent Document 1 discloses a floating structure that floats in a liquid that fills the interior of a seismic isolation pit. The floating structure of Patent Document 1 includes, for example, an air chamber on the side.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-184343 Summary of the Invention

[0006] Technical problem to be solved by the invention

[0007] However, in the floating structure described in Patent Document 1, if an earthquake occurs, the longitudinal waves (compression waves) caused by the earthquake propagate through the fluid, thereby stimulating a response in the floating structure and the equipment carried thereon (hereinafter referred to as the carried equipment). As a result, the floating structure and the carried equipment may vibrate significantly. Although the floating structure described in Patent Document 1 is provided with an air chamber, simply providing the air chamber does not necessarily suppress the excitation of the response of the floating structure and the carried equipment. Therefore, it is necessary to reduce the impact of earthquakes on the floating structure and the carried equipment.

[0008] The present disclosure aims to reduce the excitation of a floating structure and mounted equipment in response to an earthquake.

[0009] Solutions for solving the above technical problems

[0010] In order to solve the above-mentioned technical problems, a floating seismic isolation system as one solution of the present invention comprises: a liquid storage portion for storing liquid; a floating structure for floating on the liquid; and a gas storage space for storing gas, which is arranged at a position in contact with the liquid and for storing gas, and the volume of the gas storage space is set based on the natural vibration frequency of the system in response to seismic waves propagating in a fluid containing liquid and gas.

[0011] The volume of the gas storage space may be set so that the natural vibration frequency of the system responding to earthquake waves is lower than the natural vibration frequency of the floating structure and the equipment mounted on the floating structure.

[0012] The volume of the gas storage space may be set so that the natural frequency of the system responding to earthquake waves is less than 1 Hz.

[0013] Alternatively, the larger the volume of the gas storage space, the smaller the bulk modulus of the fluid, and the smaller the natural vibration frequency of the system responding to the seismic wave.

[0014] Alternatively, the system that responds to earthquake waves may include a floating structure, liquid, and gas, and the natural frequency f2 of the system that responds to earthquake waves may be expressed by the following mathematical formula (4).

[0015] [Number 1]

[0016]

[0017] An orifice may be provided in the gas storage space.

[0018] Effects of the Invention

[0019] According to the present disclosure, it is possible to reduce the excitation of a floating structure and mounted equipment in response to an earthquake. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] [ Figure 1 ] Figure 1 This is a schematic configuration diagram of the floating body seismic isolation system in the first embodiment.

[0021] [Figure 2] Figure 2A This is a top view of the floating isolation system as viewed from above. Figure 2B It is a cross-sectional view of the floating isolation system.

[0022] [Figure 3] Figure 3A Yes Figure 2B The graph shown is a graph of the relationship between the depth d0 and the natural vibration frequency. Figure 3B This is a graph showing the relationship between the volume Va of the gas storage space and the natural vibration frequency.

[0023] [Figure 4] Figure 4A Graph showing the acceleration time history waveform (input wave) of seismic activity. Figure 4B The volume of the gas storage space is Va = 0m 3 Graph of acceleration time history waveforms of seismic responses of floating structures and mounted equipment under the conditions of . Figure 4C The volume of the gas storage space is Va = 1000m 3 Graph of acceleration time history waveforms of seismic responses of floating structures and mounted equipment under the conditions of . Figure 4D The volume of the gas storage space is Va = 10000m3 Graph of acceleration time history waveforms of seismic responses of floating structures and mounted equipment under the conditions of .

[0024] [ Figure 5 ] Figure 5 This is a graph showing an example of a response spectrum when the volume of the gas storage space is changed.

[0025] [ Figure 6 ] Figure 6 This is a schematic configuration diagram of a floating-type seismic isolation system in the second embodiment.

[0026] [ Figure 7 ] Figure 7 This is a schematic configuration diagram of a floating-type seismic isolation system in a third embodiment.

[0027] [ Figure 8 ] Figure 8 This is a schematic configuration diagram of a floating-type seismic isolation system in a fourth embodiment.

[0028] [ Figure 9 ] Figure 9 This is a schematic configuration diagram of a floating-type seismic isolation system in the fifth embodiment.

[0029] [ Figure 10 ] Figure 10 This is a graph showing an example of a response spectrum when the attenuation ratio is changed.

[0030] [ Figure 11 ] Figure 11 This is a schematic diagram of the structure of a floating type seismic isolation system in the sixth embodiment.

[0031] [ Figure 12 ] Figure 12 This is a schematic diagram of the structure of the floating type seismic isolation system in the seventh embodiment. DETAILED DESCRIPTION

[0032] The following describes embodiments of the present disclosure in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely illustrative for ease of understanding and, unless otherwise stated, do not limit the present disclosure. Furthermore, in this specification and the accompanying drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, thereby omitting any repetitive description of these elements. Furthermore, illustrations of elements not directly related to the present disclosure are omitted.

[0033] (First embodiment)

[0034] Figure 1 FIG is a schematic diagram of the floating type seismic isolation system 100 in the first embodiment. Figure 1As shown, the floating seismic isolation system 100 includes a liquid storage portion 110 , a floating structure 120 and a gas containing portion 130 .

[0035] The liquid storage portion 110 includes a recessed portion 112. A liquid 114 is stored in the recessed portion 112. The liquid 114 is, for example, water. However, the present invention is not limited thereto, and the liquid 114 may be any liquid other than water, or may be another liquid primarily composed of water (e.g., seawater).

[0036] The floating structure 120 is disposed so as to float in the liquid 114 stored in the liquid storage unit 110. The floating structure 120 is disposed so as to be separated from the wall of the liquid storage unit 110, i.e., the recessed portion 112. The floating structure 120 is, for example, a floating nuclear power plant. However, this is not limiting. The floating structure 120 may be a structure of other equipment, such as a wind power plant, a wave power plant, or a solar power plant. Furthermore, it may be a structure equipped with any equipment. In this embodiment, the floating structure 120 is, for example, a floating structure floating in an artificial lake, but it may also be an offshore facility floating in the sea.

[0037] The gas storage unit 130 forms a gas storage space 132. Gas 134 is contained within the gas storage space 132. The gas storage space 132 is located in a location in contact with the liquid 114 and is sealed by the floating structure 120. In this embodiment, the gas storage unit 130 is recessed in the center of the bottom surface of the floating structure 120, and the gas storage space 132 is formed within the gas storage unit 130. Figure 1 The gas storage space 132 in the example is a closed space surrounded by the five walls of the gas storage part 130 and the liquid surface of the liquid 114. The gas storage space 132 only needs to be provided at a location in contact with the liquid 114 and be sealed, and may not be formed in the floating structure 120. For example, the gas storage space 132 may be provided in the liquid 114 (see Figure 7 ), can also be provided in the liquid storage portion 110 (refer to Figure 8 ).

[0038] Furthermore, when an earthquake occurs, longitudinal waves (compression waves) generated by the earthquake propagate through the fluid comprising liquid 114 and gas 134, thereby exciting responses in floating structure 120 and the equipment mounted thereon. Consequently, floating structure 120 and the equipment mounted thereon may vibrate significantly.

[0039] Figure 2A-2B This is a schematic model diagram of a floating structure 120 that vibrates up and down due to earthquake waves. Figure 2A This is a top view of the floating seismic isolation system 100 as viewed from above. Figure 2B is a cross-sectional view of the floating seismic isolation system 100 .

[0040] exist Figure 2A In FIG. 1 , A represents the vertical projection area of ​​the floating structure 120, and B represents the vertical projection area of ​​the liquid 114. Here, the projection area B is obtained by subtracting the projection area A from the projection area of ​​the recessed portion 112 in the vertical direction.

[0041] Figure 2B Where m represents the mass of the floating structure 120. g represents the acceleration due to gravity. h0 represents the depth (distance) from the bottom surface 120a of the floating structure 120 to the surface 114a of the liquid 114. d0 represents the depth (distance) from the bottom surface 112a of the recessed portion 112 to the bottom surface 120a of the floating structure 120. X0 represents the displacement of the liquid storage portion 110 due to the vertical vibration. X1 represents the displacement of the floating structure 120 due to the vertical vibration. X2 represents the displacement of the surface 114a of the liquid 114 due to the vertical vibration.

[0042] Here, it is considered that the vertical vibration of the floating structure 120 caused by earthquake waves can be expressed by the following equations of motion (1) and (2).

[0043] [Number 1]

[0044]

[0045] In mathematical formulas (1) and (2), ρ represents the density of the liquid 114. A and F B ΔF represents the load variation caused by the sinking and floating of the floating structure 120. A and ΔF B Indicates the load variation caused by the volume change of the liquid 114.

[0046] Solving the above equations of motion yields the formulas for the natural frequencies of the two vibration modes shown in the following equations (3) and (4). The natural frequencies shown in equations (3) and (4) represent the natural frequencies of the floating structure 120, liquid 114, and gas 134 when operating as a system (hereinafter referred to as the system). Equation (3) represents the formula for the natural frequency f1 of the system's first mode (hereinafter referred to as Mode 1), and Equation (4) represents the formula for the natural frequency f2 of the system's second mode (hereinafter referred to as Mode 2).

[0047] [Number 2]

[0048]

[0049] [Number 3]

[0050]

[0051] In the mathematical formula (4), Kv represents the bulk modulus (hereinafter referred to as equivalent bulk modulus) of the entire fluid including the liquid 114 and the gas 134 , and can be expressed by the following mathematical formula (5).

[0052] [Number 4]

[0053]

[0054] In mathematical formula (5), Ka represents the bulk modulus of gas 134, and Kw represents the bulk modulus of liquid 114. Furthermore, α represents the ratio of the volume of gas 134 to the total volume of liquid 114 and gas 134. Here, assuming that the volume of liquid 114 is Vw and the volume of gas 134 (here, the volume of gas storage space 132) is Va, the ratio α can be expressed as: Va / (Vw+Va).

[0055] As can be seen from equation (5), the equivalent bulk modulus Kv is correlated with the ratio α. Specifically, the equivalent bulk modulus Kv is correlated with the volume Va of the gas storage space 132 and the volume Vw of the liquid 114. Here, as the volume Va of the gas storage space 132 increases, the ratio α increases, and the equivalent bulk modulus Kv decreases.

[0056] Figure 3A-3B This is a graph showing an example of the calculation results of the natural vibration frequency using mathematical formulas (3) and (4). Figure 3A-3B In the figure, the black triangles represent the natural frequency f1 of mode 1 calculated using equation (3), and the black diamonds represent the natural frequency f2 of mode 2 calculated using equation (4). In addition, the dotted line represents the natural frequency f3 of the equipment mounted on the floating structure 120. Here, the natural frequency f3 of the equipment is set to 5 Hz as an example. Figure 3A Yes Figure 2B The graph shown is a graph of the relationship between the depth d0 and the natural vibration frequency. Figure 3B Graph showing the relationship between the volume Va of the gas storage space 132 and the natural frequency.

[0057] The parameter used here is mass m = 1×10 9 kg, projected area A = 40000m 2 , the density of liquid 114 is ρ = 1000 kg / m 3 , the bulk elastic modulus of liquid 114 is Kw = 2.25 × 10 9 N / m2 , the bulk elastic modulus of gas 134 is Ka=1.40×10 5 N / m 2 In addition, about Figure 3B As an example, the parameters shown in the figure are those when the volume Va of the gas storage space 132 is changed. When the volume Va of the gas storage space 132 is 10000 m 3 When the ratio α = 0.00973, the equivalent bulk elastic modulus Kv = 1.43 × 10 7 N / m 2 .

[0058] like Figure 3A As shown, even if the depth d0 changes, the natural frequency f1 of mode 1 remains substantially constant. On the other hand, as the depth d0 increases, the natural frequency f2 of mode 2 decreases, and can become a value smaller than the natural frequency f3.

[0059] like Figure 3B As shown, even if the size of the gas storage space 132 changes, the natural frequency f1 of mode 1 remains substantially constant. On the other hand, as the volume Va of the gas storage space 132 increases, the natural frequency f2 of mode 2 decreases, and can become even lower than the natural frequency f3.

[0060] Figures 4A to 4D This is a graph showing an example of calculation results of earthquake response when the volume Va of the gas storage space 132 is changed. Figure 4A is a graph showing the acceleration time history waveform (input wave) of seismic activity. Figure 4A The input waves shown in the figure and the seismic waves used in the calculation are the up-and-down components of the Tsukidano observation waves of the Tohoku Pacific Offshore Earthquake observed by the K-net of the National Institute of Science and Technology for Disaster Prevention.

[0061] Figure 4B The volume of the gas storage space 132 is Va=0m 3 Graph of acceleration time history waveforms of seismic responses of the floating structure 120 and mounted equipment under the condition of . Figure 4C The volume of the gas storage space 132 is Va=1000m 3 Graph of acceleration time history waveforms of seismic responses of the floating structure 120 and mounted equipment under the condition of . Figure 4D The volume of the gas storage space 132 is Va=10000m 3 The acceleration time history waveform of the seismic response of the floating structure 120 and the equipment mounted thereon is shown in FIG. Figures 4A to 4DAs shown, the larger the volume Va of the gas storage space 132 is, the more the seismic response of the floating structure 120 and the equipment on board can be reduced.

[0062] Figure 5 : is a graph showing an example of a response spectrum when the volume Va of the gas storage space 132 is changed. Figure 5 In the figure, the volume Va of the gas storage space 132 is shown by a solid line. 3 The response spectrum of the case of Va = 1000m is shown by the single-dot chain line. 3 The dotted line shows the response spectrum in the case of volume Va = 10000m 3 Here, the change in the response spectrum when the volume Va of the gas storage space 132 is changed when the attenuation ratio h=0.05 is shown.

[0063] In this embodiment, the natural vibration frequency of the equipment mounted on the floating structure 120 is several Hz (for example, 5 Hz) to several tens of Hz (for example, 30 Hz). 3 In the case of , the natural vibration frequency f2 of the system's mode 2 is similar to the natural vibration frequency of the equipment carried on the floating structure 120. Therefore, if Figure 5 As shown, in volume Va = 0m 3 In the case of an earthquake, the longitudinal wave (compression wave) caused by the earthquake excites the response of the equipment mounted on the floating structure 120, causing the equipment to vibrate greatly.

[0064] Here, the natural vibration characteristics of the waves propagating in the fluid depend on the bulk modulus of the fluid. In this embodiment, by appropriately setting the volume Va of the gas storage space 132, the equivalent bulk modulus Kv determined by the liquid 114 and the gas 134 is adjusted, thereby separating the natural vibration frequency f2 of the system's mode 2 from the natural vibration frequencies of the floating structure 120 and the onboard equipment. Figure 5 Medium volume Va = 1000m 3 , 10000m 3 As shown, it is possible to suppress the situation where the seismic response of the system is excited.

[0065] As described above, according to this embodiment, the volume Va of the gas storage space 132 is set based on the natural frequency of the system that responds to seismic waves propagating through the fluid containing the liquid 114 and the gas 134. Specifically, the volume Va of the gas storage space 132 is set so that the natural frequency of the system that responds to seismic waves is lower than the natural frequency of the floating structure 120 and the onboard equipment.

[0066] The natural frequency of the system responding to seismic waves is the natural frequency f2 of mode 2, expressed by equation (4). The larger the volume Va of the gas storage space 132, the smaller the bulk modulus (equivalent bulk modulus Kv) of the fluid, and the smaller the natural frequency of the system responding to seismic waves. This reduces the excitation of the floating structure 120 and its onboard equipment by earthquakes.

[0067] The volume Va of the gas storage space 132 is set so that the natural frequency of the system responding to earthquake waves is less than 1 Hz. The natural frequency (primary frequency) of a typical earthquake is, for example, 1 Hz to 10 Hz. By setting the natural frequency of the system to less than 1 Hz, the natural frequency of the system can be separated from the natural frequency of the earthquake. As a result, the excitation of the floating structure 120 and its onboard equipment by the earthquake can be reduced.

[0068] (Second embodiment)

[0069] Figure 6 This is a schematic diagram of the structure of a floating seismic isolation system 200 according to the second embodiment. Components substantially identical to those of the floating seismic isolation system 100 according to the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted. The floating seismic isolation system 200 according to the second embodiment differs from the floating seismic isolation system 100 according to the first embodiment in that it includes a gas container 230 in place of the gas container 130 of the first embodiment. All other components are identical to the floating seismic isolation system 100 according to the first embodiment.

[0070] The gas storage portion 230 is formed with a gas storage space 232. Gas 134 is stored in the gas storage space 232. The gas storage space 232 is provided at a portion in contact with the liquid 114 and is formed by being sealed by the floating structure 120. The gas storage space 232 is formed at a position closer to the outer peripheral surface than the central portion of the bottom surface of the floating structure 120. In the present embodiment, two gas storage spaces 232 are provided at positions that are point-symmetrical with respect to the center of the bottom surface of the floating structure 120. However, this is not limiting, and three or more gas storage spaces 232 may be provided at positions that are point-symmetrical with respect to the center of the bottom surface of the floating structure 120. Thus, compared with the floating structure 120 of the first embodiment, the posture stability can be improved.

[0071] According to the second embodiment, similar to the first embodiment, the volume Va of the gas storage space 232 is set based on the natural frequency of the system that responds to seismic waves propagating through the fluid containing the liquid 114 and the gas 134. Specifically, the volume Va of the gas storage space 232 is set so that the natural frequency of the system that responds to seismic waves is lower than the natural frequency of the floating structure 120 and the onboard equipment. This achieves the same functions and effects as the first embodiment.

[0072] (Third embodiment)

[0073] Figure 7 This is a schematic diagram of the structure of a floating seismic isolation system 300 according to the third embodiment. Components substantially identical to those of the floating seismic isolation system 100 according to the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted. The floating seismic isolation system 300 according to the third embodiment differs from the floating seismic isolation system 100 according to the first embodiment in that it includes a gas container 330 in place of the gas container 130 of the first embodiment. All other components are identical to the floating seismic isolation system 100 according to the first embodiment.

[0074] The gas storage section 330 includes an elastic membrane 340 and a gas storage space 332 formed inside the elastic membrane 340. The elastic membrane 340 is made of, for example, a rubber material and has elasticity. The gas 134 is stored in the gas storage space 332. The gas storage space 332 is provided at a location in contact with the liquid and is sealed in the liquid 114. In this embodiment, the gas storage space 332 is located on the bottom surface 112a of the recessed portion 112 of the liquid storage section 110 (see FIG. 1 ). Figure 2B ) and the bottom surface 120a of the floating structure 120 (refer to Figure 2B ). However, this is not limiting; as long as the gas storage space 332 is sealed within the liquid 114 and is not in contact with the atmosphere, it may be provided at any location within the liquid 114. Thus, for example, when multiple floating structures 120 are arranged to float within the liquid 114, the gas storage space 332 can be shared rather than formed in each floating structure 120.

[0075] According to the third embodiment, similar to the first embodiment, the volume Va of the gas storage space 332 is set based on the natural frequency of the system that responds to seismic waves propagating through the fluid containing the liquid 114 and the gas 134. Specifically, the volume Va of the gas storage space 332 is set so that the natural frequency of the system that responds to seismic waves is lower than the natural frequency of the floating structure 120 and the onboard equipment. This achieves the same functions and effects as the first embodiment.

[0076] (Fourth embodiment)

[0077] Figure 8 This is a schematic diagram of the structure of a floating seismic isolation system 400 according to the fourth embodiment. Components substantially identical to those of the floating seismic isolation system 100 according to the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. The floating seismic isolation system 400 according to the fourth embodiment differs from the floating seismic isolation system 100 according to the first embodiment in that it includes a gas container 430 in place of the gas container 130 of the first embodiment. All other components are identical to the floating seismic isolation system 100 according to the first embodiment.

[0078] The gas storage unit 430 is formed with a gas storage space 432. Gas 134 is contained within the gas storage space 432. The gas storage space 432 is provided in a location that comes into contact with the liquid and is hermetically sealed within the liquid storage unit 110. Thus, if it is difficult to form the gas storage space 132 within the floating structure 120, the gas storage space 432 can be formed within the liquid storage unit 110 instead of within the floating structure 120.

[0079] According to the fourth embodiment, similar to the first embodiment, the volume Va of the gas storage space 432 is set based on the natural frequency of the system that responds to seismic waves propagating through the fluid containing the liquid 114 and the gas 134. Specifically, the volume Va of the gas storage space 432 is set so that the natural frequency of the system that responds to seismic waves is lower than the natural frequency of the floating structure 120 and the onboard equipment. This achieves the same functions and effects as the first embodiment.

[0080] (Fifth embodiment)

[0081] Figure 9 This is a schematic diagram of the floating seismic isolation system 500 in the fifth embodiment. Components substantially identical to those in the floating seismic isolation system 100 in the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted. The floating seismic isolation system 500 in the fifth embodiment differs from the floating seismic isolation system 100 in the first embodiment in that an orifice 510 is added to the gas storage space 132 in the first embodiment. All other components are identical to the floating seismic isolation system 100 in the first embodiment.

[0082] Orifice 510 is disposed within gas storage space 132. The placement of orifice 510 within gas storage space 132 creates resistance when gas 134 passes through orifice 510. This resistance acts as a damping force against the vibration response caused by the transmission of seismic waves to floating structure 120 and onboard equipment. This damping force suppresses the vibration response of floating structure 120 and onboard equipment caused by the transmission of seismic waves.

[0083] Figure 10 This is a graph showing an example of a response spectrum when the attenuation ratio h is changed. Figure 10 In FIG. 1 , the double-dashed line shows the response spectrum when the attenuation ratio h = 0.00, the single-dashed line shows the response spectrum when h = 0.05, and the dotted line shows the response spectrum when h = 0.10. Here, the volume Va of the gas storage space 132 is shown as 10000m 3 Changes in the response spectrum when the attenuation ratio h is changed.

[0084] like Figure 10 As shown, as the attenuation ratio h increases, the response acceleration can be reduced, and the vibration response of the floating structure 120 and the onboard equipment caused by the transmission of the earthquake wave can be suppressed.

[0085] According to the fifth embodiment, the orifice 510 is provided in the gas storage space 132. This can further suppress the vibration response of the floating structure 120 and onboard equipment caused by the transmission of earthquake waves, in addition to the functions and effects of the first embodiment.

[0086] (Sixth embodiment)

[0087] Figure 11 This is a schematic diagram of the structure of a floating seismic isolation system 600 according to the sixth embodiment. Components substantially identical to those of the floating seismic isolation system 200 according to the second embodiment are denoted by the same reference numerals, and descriptions thereof are omitted. The floating seismic isolation system 600 according to the sixth embodiment differs from the floating seismic isolation system 200 according to the second embodiment in that an orifice 610 is added to the gas storage space 232 of the second embodiment. All other components are identical to the floating seismic isolation system 200 according to the second embodiment.

[0088] The orifices 610 are disposed in each of the two gas storage spaces 232. By disposing the orifices 610 in the gas storage spaces 232, in addition to the functions and effects of the second embodiment, the vibration response of the floating structure 120 and the onboard equipment caused by the transmission of earthquake waves can be further suppressed.

[0089] (Seventh embodiment)

[0090] Figure 12 This is a schematic diagram of the structure of a floating seismic isolation system 700 according to the seventh embodiment. Components substantially identical to those of the floating seismic isolation system 400 according to the fourth embodiment are denoted by the same reference numerals, and their descriptions are omitted. The floating seismic isolation system 700 according to the seventh embodiment differs from the floating seismic isolation system 400 according to the fourth embodiment in that an orifice 710 is added to the gas storage space 432 of the fourth embodiment. All other components are identical to the floating seismic isolation system 400 according to the fourth embodiment.

[0091] The orifice 710 is disposed in the gas storage space 432. Providing the orifice 710 in the gas storage space 432 can further suppress the vibration response of the floating structure 120 and onboard equipment caused by the transmission of earthquake waves, in addition to the effects and functions of the fourth embodiment.

[0092] While the embodiments of the present disclosure have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the embodiments. It is obvious that those skilled in the art can conceive of various variations or modifications within the scope of the claims, and it is understood that these also fall within the technical scope of the present disclosure.

[0093] Furthermore, the floating seismic isolation systems 100, 200, 300, 400, 500, 600, and 700 of the above-mentioned embodiments can be combined. For example, the floating seismic isolation system 100 of the first embodiment, the floating seismic isolation system 200 of the second embodiment, and the floating seismic isolation system 300 of the third embodiment can also include the gas container 430 of the fourth embodiment. Furthermore, the floating seismic isolation system 100 of the first embodiment and the floating seismic isolation system 200 of the second embodiment can also include the gas container 330 of the third embodiment. Furthermore, the floating seismic isolation system 100 of the first embodiment can also include the gas container 230 of the second embodiment.

[0094] Description of Reference Numerals

[0095] 100 floating body isolation system

[0096] 110 Liquid Storage Department

[0097] 114 liquid

[0098] 120 floating structure

[0099] 132 Gas holding space

[0100] 134 gas

[0101] 200 floating body isolation system

[0102] 232 gas holding space

[0103] 300 floating body isolation system

[0104] 332 gas holding space

[0105] 340 elastic membrane

[0106] 400 floating body isolation system

[0107] 432 gas holding space

[0108] 500 floating body isolation system

[0109] 510 throttle

[0110] 600 floating body isolation system

[0111] 610 throttle

[0112] 700 floating body isolation system

[0113] 710 throttle hole.

Claims

1. A floating type seismic isolation system, characterized in that: have: a liquid storage portion for storing liquid; a floating structure disposed in a floating manner in the liquid; and The gas storage space is provided at a position in contact with the liquid and stores gas. The volume of the gas storage space is set based on the natural vibration frequency of the system that responds to seismic waves propagating in the fluid containing the liquid and the gas, The volume of the gas storage space is set so that the natural vibration frequency of the system responding to the seismic wave is lower than the natural vibration frequency of the floating structure and the equipment mounted on the floating structure.

2. A floating seismic isolation system, characterized in that: have: a liquid storage portion for storing liquid; a floating structure disposed in a floating manner in the liquid; and The gas storage space is provided at a position in contact with the liquid and stores gas. The volume of the gas storage space is set based on the natural vibration frequency of the system that responds to seismic waves propagating in the fluid containing the liquid and the gas, A throttle hole is provided in the gas accommodating space.

3. The floating seismic isolation system according to claim 1 or 2, wherein: The volume of the gas containing space is set so that the natural vibration frequency of the system responding to the seismic wave is less than 1 Hz.

4. The floating seismic isolation system according to claim 1 or 2, wherein: The larger the volume of the gas accommodation space, the smaller the bulk elastic modulus of the fluid, and the smaller the natural vibration frequency of the system responding to the seismic wave.

5. The floating seismic isolation system according to claim 1 or 2, wherein: The system responding to the seismic wave includes the floating structure, the liquid and the gas, The natural frequency f2 of the system that responds to the earthquake wave is expressed by the following mathematical formula (4): [Number 1] In mathematical formula (4), A represents the projected area of ​​the floating structure in the vertical direction, Kv represents the bulk elastic modulus of the fluid as a whole including the liquid and the gas, d0 represents the depth, i.e., the distance, from the bottom surface of the recessed portion of the liquid storage portion to the bottom surface of the floating structure, ρ represents the density of the liquid, and m represents the mass of the floating structure.

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