Seismic isolation device model, and centrifugal force loading experimental apparatus.

Abstract

The present invention aims to provide a seismic isolation device model and a centrifugal force loading experimental apparatus that can improve the accuracy of experiments and analyses. [Solution] The seismic isolation device model 500 according to the present invention is a seismic isolation device model 500 used in a centrifugal force loading experimental apparatus, and comprises a ground model 20, a foundation 30 embedded in the ground model 20, an upper structure 40 provided above the foundation 30, a restoring force providing member 60 that provides a restoring force to return the upper structure 40 to its initial position when the upper structure 40 moves relative to the foundation 30, and a low friction member 70 provided between the foundation 30 and the upper structure 40 to slidably support the upper structure 40.

Description

Technical Field

[0001] The present invention relates to a seismic isolation device model and a centrifugal load test device.

Background Art

[0002] In order to understand the behavior of the ground during an earthquake, centrifugal load tests are often conducted. In this centrifugal load test, by applying a centrifugal acceleration N times the gravitational acceleration to a ground model that is scaled down to 1 / N of the actual object, a stress field similar to the actual phenomenon is reproduced, and the behavior of the full-scale ground when static or dynamic forces act is verified. Also, as a model used in this centrifugal load test, not only a ground model but also a structure model can be combined to verify the interaction between the ground and the structure.

[0003] And, as a model used in the centrifugal load test, a model considering a seismic isolation device has also been studied. For example, in Non-Patent Document 1, in order to simulate a seismic isolation device, a model is proposed in which the upper structure is supported by rollers with respect to the base, and rubber is provided between the upper structure and a panel fixed to the base.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Non-patent document 1 attempts to simulate a seismic isolation device using the above-described configuration, but because the foundation is located above the ground surface, there is a problem in that the dynamic interaction between the ground and the structure cannot be adequately considered. Therefore, it was difficult to say that sufficient accuracy of reproduction could be guaranteed. Therefore, the inventors considered that the accuracy of experiments and analyses could be improved by configuring the seismic isolation device model used in the centrifugal force loading experiment apparatus to take into account the dynamic interaction between the ground and the structure.

[0006] From this perspective, the object of the present invention is to provide a seismic isolation device model and a centrifugal force loading experimental apparatus that can improve the accuracy of experiments and analyses. [Means for solving the problem]

[0007] The aforementioned problem can be solved by the following means. The seismic isolation device model according to the present invention is a seismic isolation device model used in a centrifugal force loading experimental apparatus, and comprises a ground model, a foundation embedded in the ground model, a superstructure provided above the foundation, a restoring force providing member that provides a restoring force to return the superstructure to its initial position when the superstructure moves relative to the foundation, and a low-friction member provided between the foundation and the superstructure to slidably support the superstructure. According to the present invention, since the foundation of the seismic isolation device model is embedded in the ground model, the configuration is in line with the actual situation in which the foundation of a seismic isolation structure is embedded in the ground, and the effect of so-called "embedment" can be taken into consideration. As a result, according to the present invention, the accuracy of experiments and analyses can be improved compared to using a model that does not take into account the dynamic interaction of the embedded portion, such as Non-Patent Document 1. The seismic isolation device model according to the present invention preferably includes an underground wall on the outer periphery of the foundation that surrounds a space that accommodates the lower part of the superstructure and prevents the ground model from flowing into the space. According to the present invention, since it includes an underground wall section, it is possible to avoid situations in which the ground model flows into the space that accommodates the lower part of the superstructure. Preferably, the seismic isolation device model according to the present invention has at least two superstructures spaced apart (in other words, the superstructures have two embedded parts that protrude downward and are spaced apart), the foundation comprises a support portion positioned between the two superstructures (two embedded parts), and the restoring force-applying member is a spring member provided between the support portion and the two superstructures (two embedded parts). Alternatively, preferably, the seismic isolation device model according to the present invention has a foundation comprising two support portions positioned on both sides of the superstructure in the sliding direction, and the restoring force-applying member is a spring member provided between the two support portions and the superstructure. According to the present invention, by providing a spring member between the support part and the superstructure part, a restoring force can be applied to the superstructure part, thereby accurately reproducing the behavior of an actual seismic isolation device. As a result, according to the present invention, the "behavior of the seismic isolation device model" and the "behavior of an actual structure equipped with a seismic isolation device" appropriately satisfy the similarity law, further improving the accuracy of experiments and analyses. Furthermore, according to the present invention, parameter setting during numerical analysis can be simplified by using the spring constant of the spring member, etc. In the seismic isolation device model according to the present invention, it is preferable that the low-friction member is one of the following: a plurality of roll members that rotate about an axis perpendicular to the sliding direction, a slide rail that guides the sliding movement of the superstructure, and a sliding plate that reduces the frictional resistance between the foundation and the superstructure. According to the present invention, by using a specific low-friction member, the superstructure can be slidably supported relative to the foundation, and the behavior of the actual seismic isolation device can be reproduced more accurately. The centrifugal force loading experimental apparatus according to the present invention is an apparatus for applying centrifugal force to the aforementioned seismic isolation device model. According to the present invention, by using the aforementioned seismic isolation device model, it is possible to simplify parameter setting during numerical analysis and improve the accuracy of the analysis. [Effects of the Invention]

[0008] The seismic isolation device model and centrifugal force loading experimental apparatus according to the present invention can improve the accuracy of experiments and analyses. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of the entire centrifugal force loading experimental apparatus according to this embodiment. [Figure 2] This is a schematic diagram of the entire seismic isolation device model according to the first embodiment. [Figure 3A] This is an enlarged schematic diagram of a seismic isolation device model according to the first embodiment, and is a side view with the underground wall section on the foreground removed. [Figure 3B] This is an enlarged schematic diagram of a seismic isolation device model according to the first embodiment, and is a top view showing a state in which a part of the superstructure (plate part and main body part) has been removed. [Figure 3C] This is an enlarged schematic diagram of a seismic isolation device model according to the first embodiment, and is a cross-sectional view taken in the direction of arrow AA in Figure 3A. [Figure 4A] This is an enlarged schematic diagram of a seismic isolation device model according to the second embodiment, and is a side view with the underground wall section on the foreground removed. [Figure 4B] This is an enlarged schematic diagram of a seismic isolation device model according to the second embodiment, and is a top view showing a state in which a part of the superstructure (plate part and main body part) has been removed. [Figure 4C] This is an enlarged schematic diagram of a seismic isolation device model according to the second embodiment, and is a cross-sectional view taken along the BB arrow in Figure 4A. [Figure 5A] This is an enlarged schematic diagram of a seismic isolation device model according to the third embodiment, and is a side view with the underground wall section on the foreground removed. [Figure 5B] This is an enlarged schematic diagram of a seismic isolation device model according to the third embodiment, and is a top view showing a state in which a part of the superstructure (plate part and main body part) has been removed. [Modes for carrying out the invention]

[0010] Hereinafter, a form for implementing the seismic isolation device model and the centrifugal force loading experiment device according to the present invention will be described with reference to the drawings. In addition, "up, down, left, right, front, and back" in this specification are as shown in the directions in the drawings.

[0011] [Centrifugal Force Loading Experiment Device] FIG. 1 is an overall schematic diagram of the centrifugal force loading experiment device according to the present embodiment. As shown in FIG. 1, the centrifugal force loading experiment device E according to the present embodiment includes a rotating shaft 100 provided perpendicular to the ground, a rotating arm 200 that rotates in a horizontal plane around the rotating shaft 100, two buckets 300 and 400 respectively provided at both ends of the rotating arm 200, a seismic isolation device model 500 mounted on one bucket 300, and a counterweight 600 mounted on the other bucket 400. The centrifugal force loading experiment device E causes a desired centrifugal acceleration to act (load) on the seismic isolation device model 500 mounted on the bucket 300 at the end of the rotating arm 200 by the rotation of the rotating arm 200 in the horizontal plane, and reproduces a stress field equivalent to the actual phenomenon. The configuration of the centrifugal force loading experiment device E may be a conventionally known configuration other than the seismic isolation device model 500 described later, and is not particularly limited. Hereinafter, the seismic isolation device model 500 used in the centrifugal force loading experiment device E will be described in detail using the first to third embodiments. When describing the second and third embodiments, descriptions of configurations common to the already described embodiments will be omitted, and descriptions will be centered on the different configurations.

[0012] [Seismic Isolation Device Model (First Embodiment)] FIG. 2 is an overall schematic diagram of the seismic isolation device model according to the first embodiment. As shown in FIG. 2, the seismic isolation device model 500 according to the first embodiment is housed in a soil tank 10 as a whole, and mainly includes a ground model 20, a foundation part 30, a superstructure part 40, and a pile part 50. The seismic isolation device model 500 is a model used in the centrifugal force loading experiment device E and is a "model considering the behavior of the seismic isolation device". Figure 3 is an enlarged schematic diagram of a seismic isolation device model according to the first embodiment. More specifically, Figure 3A is a side view of the seismic isolation device model with the foreground underground wall section removed, Figure 3B is a top view of the seismic isolation device model with a portion of the superstructure (plate section and main body section) removed, and Figure 3C is a cross-sectional view of the seismic isolation device model taken in the direction of arrow AA in Figure 3A. The configurations of the seismic isolation device model 500 according to the first embodiment will be described below with reference to Figures 3A to 3C.

[0013] (Ground model) The ground model 20 is a structure that mimics actual ground conditions. The ground model 20 is not particularly limited, as long as it is manufactured in accordance with conventionally known methods for manufacturing ground models, such as selecting the soil to be used, supplying pore fluid, and consolidating, in order to obtain appropriate experimental results.

[0014] (Foundation) The foundation section 30 is a structure that mimics the foundation (substructure) that is actually buried in the ground of a real structure. The foundation 30 is plate-shaped and has a rectangular shape when viewed from above. Unlike in Non-Patent Document 1, the foundation 30 is embedded in the ground model 20. Underground wall sections 31 are formed on each of the four sides of the outer perimeter of the foundation section 30, extending upward. These underground wall sections 31 enclose the space that accommodates the lower part (buried section 41) of the superstructure section 40, which will be described later, thereby preventing the ground model 20 from flowing into the space. In addition, protrusions 31D extending in the left-right direction are formed on the front and back underground wall sections 31, and these protrusions 31D fit into recesses 41D of the superstructure section 40 (buried section 41), which will be described later, thereby controlling the movement of the superstructure section 40 relative to the foundation section 30 in the left-right direction. In this specification, the left-right direction is the same direction as the excitation direction used to excite the seismic isolation device model 500 when verifying the effects of earthquakes, etc. The base portion 30 has a plate-shaped support portion 32 formed in the center of its upper surface, extending in the direction from front to back. Restoring force-applying members 60, which will be described later, are provided on both the left and right sides of this support portion 32.

[0015] The foundation 30 is supported from below by multiple pile sections 50. While the pile sections 50 are modeled after actual piles, they are not necessary when verifying structures that do not use piles. In other words, the pile sections 50 are not an essential component of the seismic isolation device model 500.

[0016] (Superstructure) The superstructure 40 is a model that mimics the structure (superstructure) of the above-ground portion of an actual structure. The superstructure 40 comprises two buried sections 41 located in the space enclosed by the foundation section 30 and the underground wall section 31, a plate section 42 fixed to the upper surface of the two buried sections 41, and a main body section 43 fixed to the upper surface of the plate section 42. The two buried sections 41 are each roughly rectangular and are spaced apart in the left-right direction. The buried sections 41 are placed on the low-friction member 70. Recesses 41D extending in the left-right direction are formed on both the front and back sides of the buried sections 41. The protrusions 31D of the underground wall section 31 fit into these recesses 41D, thereby controlling the movement of the superstructure section 40 relative to the foundation section 30 in the left-right direction. The plate portion 42 and the main body portion 43 of the superstructure portion 40 only need to have a shape that mimics an actual structure, and are not particularly limited.

[0017] (Restoring force-applying member) The restoring force-applying member 60, in combination with the low-friction member 70 described later, is a component that reproduces the behavior of an actual seismic isolation device. The restoring force-applying member 60 is a component that applies a restoring force to return the superstructure 40 to its initial position when the superstructure 40 moves relative to the foundation 30, and in detail, it is a plurality of spring members 60. Multiple spring members 60 are arranged to expand and contract in the left-right direction (excitation direction) in the space between the left embedded portion 41 and the support portion 32, and in the space between the right embedded portion 41 and the support portion 32. By applying a restoring force to the superstructure portion 40 through these spring members 60, the behavior of the seismic isolation device model 500 and the behavior of an actual structure equipped with a seismic isolation device appropriately satisfy the similarity law. Furthermore, by using the spring constant of the spring members 60, parameter setting during numerical analysis can be simplified. In Figure 3B, there are a total of 10 spring members 60, but the number is not particularly limited. Also, the spring members 60 can have any configuration that is a conventionally known spring, and are not particularly limited.

[0018] (Low friction material) The low-friction member 70, in combination with the aforementioned restoring force-applying member 60, is a component that reproduces the behavior of an actual seismic isolation device. The low-friction member 70 is provided between the foundation 30 and the superstructure 40 and is a component that slidably supports the superstructure 40. More specifically, it is a plurality of roll members 70 that rotate around an axis perpendicular to the sliding direction (left-right direction). Multiple roll members 70 are arranged so as to cover the upper surface of the foundation 30 with their axes facing in the front-to-back direction. The combination of these roll members 70 and the aforementioned spring members 60 ensures that the behavior of the seismic isolation device model 500 and the behavior of an actual structure equipped with a seismic isolation device satisfy the similarity law more appropriately. The number and size of the roll members 70 can be determined as appropriate in accordance with the foundation 30 and the superstructure 40.

[0019] [Model of seismic isolation device (second embodiment)] Figure 4 is an enlarged schematic diagram of a seismic isolation device model according to the second embodiment. More specifically, Figure 4A is a side view of the seismic isolation device model with the foreground underground wall section removed, Figure 4B is a top view of the seismic isolation device model with a portion of the superstructure (plate section, main body section) removed, and Figure 4C is a cross-sectional view of the seismic isolation device model taken along the BB arrow in Figure 4A. The following describes the configurations of the seismic isolation device model 500a according to the second embodiment, focusing on the differences from the first embodiment, with reference to Figures 4A to 4C.

[0020] (Foundation) The foundation 30, instead of the support portion 32 of the first embodiment, has two plate-shaped support portions 32a formed near the left and right ends, extending in the front-rear direction along the underground wall portion 31.

[0021] (Superstructure) The superstructure 40a includes two sets of buried sections 41a, each having a slit 41S, instead of the two buried sections 41 of the first embodiment. Each of the two buried sections 41a consists of a combination of three rectangular parallelepipeds connected in a front-to-back direction via two slits 41S, and is arranged with a gap between them in the front-to-back direction. A slide rail 70a, described later, is provided at the lower end of the slits 41S. In Figure 4C, the slit 41S is formed until it reaches the plate portion 42, but any configuration that allows the slide rail 70a to be formed between the embedded portion 41a and the foundation portion 30 is acceptable. Therefore, the slit 41S may be configured as a recess extending in the left-right direction on the lower surface of the embedded portion 41a.

[0022] (Restoring force-applying member) Multiple spring members 60a are arranged to expand and contract in the left-right direction (vibration direction) in the space between the left support portion 32a and the buried portion 41a, and in the space between the right support portion 32a and the buried portion 41a.

[0023] (Low friction material) As a low-friction member, a slide rail 70a is used instead of the roll member 70 of the first embodiment. The slide rail 70a is a member that guides the left-right sliding movement of the upper structure 40 relative to the base 30. The slide rail 70a is formed so as to fit into the slit 41S of the upper structure 40a (embedded portion 41a) on the upper surface of the base 30. The slide rail 70a can be of various types, such as roller type or bearing type, but any conventionally known slide rail can be used, and it is not particularly limited to that type.

[0024] [Model of seismic isolation device (third embodiment)] Figure 5 is an enlarged schematic diagram of a seismic isolation device model according to the third embodiment. More specifically, Figure 5A is a side view of the seismic isolation device model with the underground wall section on the front removed, and Figure 5B is a top view of the seismic isolation device model with a part of the superstructure (plate section, main body section) removed. The following describes the configurations of the seismic isolation device model according to the third embodiment, focusing on the differences from the first embodiment, with reference to Figures 5A and 5B.

[0025] (Low friction material) As a low-friction member, a sliding plate 70b is used instead of the roll member 70 of the first embodiment. The sliding plate 70b is a plate material that reduces frictional resistance that occurs when the superstructure 40 slides against the base 30. The sliding plate 70b is formed on the upper surface of the base 30. The sliding plate 70b may have a surface that is processed to reduce frictional resistance, but it is not particularly limited and any conventionally known sliding plate can be used.

[0026] [effect] The seismic isolation device models according to the first to third embodiments have a foundation embedded in the underground wall, thus reflecting the reality that the foundations of actual structures are embedded in the ground, and allowing for consideration of the effects of so-called "embedment." As a result, the seismic isolation device models according to the first to third embodiments allow for improved accuracy in experiments and analyses compared to using models that do not consider the dynamic interaction between the ground and the embedded portion, such as Non-Patent Document 1. The seismic isolation device models according to the first to third embodiments include a restoring force-applying member and a low-friction member, and these two members can accurately reproduce the behavior of an actual seismic isolation device. As a result, the seismic isolation device models according to the first to third embodiments appropriately satisfy the similarity law between the behavior of the seismic isolation device model and the behavior of an actual structure equipped with a seismic isolation device, thereby further improving the accuracy of experiments and analyses. In addition, the seismic isolation device models according to the first to third embodiments simplify parameter setting during numerical analysis by using the spring constant of the spring member, etc. Furthermore, the seismic isolation device models according to the first to third embodiments do not require the use of any special components.

[0027] [Differentiation] Although three embodiments of the present invention have been described above, the present invention is not limited to these embodiments and can be modified as appropriate without departing from its spirit. In the first to third embodiments, instead of a spring member, a damper with known restoring force characteristics and damping coefficient may be used as the restoring force-applying member 60. Alternatively, the restoring force-applying member 60 may be used in combination with a dashpot with a known damping coefficient (for example, by connecting the spring member and the dashpot in parallel). By employing a member with the aforementioned damping performance, the behavior of the actual seismic isolation device can be reproduced more accurately, and the accuracy of experiments and analyses can be further improved.

[0028] In the seismic isolation device model 500a according to the third embodiment shown in Figure 4A, one end of the spring member 60a is connected to each of the two support parts 32a on the left and right sides. However, the two support parts 32a may be eliminated, and one end of the spring member 60a may be connected to the underground wall parts 31 on the left and right sides.

[0029] The material of each component in the first to third embodiments may be determined appropriately so that the behavior of the actual structure can be verified. For example, an acrylic sheet may be used for the underground wall section 31. [Explanation of symbols]

[0030] 10 Earthen tank 20 Ground model 30 Foundation 31 Underground wall section 31D convex part 32 Support part 32a Support part 40 Superstructure 41 Buried part (superstructure part) 41a Buried part (superstructure part) 41D recess 41S Slit 42 Plate section (superstructure section) 43 Main body (upper structure) 50 Pile section 60. Spring member (restoring force providing member) 60a Spring member (restoring force providing member) 70 Roll members (low friction members) 70a Slide rail (low friction component) 70b Sliding plate (low friction component) 100 Rotation axis 200 rotation arm 300, 400 buckets 500 Seismic Isolation Device Model 600 counterweight E. Centrifugal Loading Experiment Apparatus

Claims

1. A seismic isolation device model used in a centrifugal force loading experimental apparatus, A geotechnical model, The foundation embedded in the aforementioned ground model, An upper structure provided above the aforementioned foundation, A restoring force-applying member that provides a restoring force to return the superstructure to its initial position when the superstructure moves relative to the base, A seismic isolation device model comprising a low-friction member provided between the base and the superstructure, which slidably supports the superstructure.

2. The seismic isolation device model according to claim 1, characterized in that the outer periphery of the foundation portion is provided with an underground wall portion that surrounds a space for housing the lower part of the superstructure portion and prevents the ground model from flowing into the space.

3. Having at least two of the above-mentioned superstructures arranged at intervals, The base portion includes a support portion positioned between the two superstructure portions, The seismic isolation device model according to claim 1 or 2, characterized in that the restoring force-applying member is a spring member provided between the support portion and the two superstructure portions, respectively.

4. The base portion comprises two support portions arranged on both sides in the sliding direction of the upper structure portion, The seismic isolation device model according to claim 1 or 2, characterized in that the restoring force-applying member is a spring member provided between the two support parts and the superstructure part, respectively.

5. The seismic isolation device model according to claim 1 or 2, characterized in that the low-friction member is one of a plurality of roll members that rotate about an axis perpendicular to the sliding direction, a slide rail that guides the sliding movement of the superstructure, and a sliding plate that reduces frictional resistance between the foundation and the superstructure.

6. A centrifugal force loading experimental apparatus for applying centrifugal force to a seismic isolation device model according to claim 1 or claim 2.

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