JP7344848B2 - Sheared soil tank for model vibration experiments - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sheared soil tank for model vibration experiments that stores model soil in vibration experiments conducted by installing the model soil on a shaking table.

A sheared soil tank is used as a test device to reproduce the behavior of the ground during an earthquake. The sheared soil tank includes a bottom plate provided on a vibrating table and a plurality of frames stacked on the bottom plate via rollers (for example, see Patent Document 1). In addition, Patent Document 2 describes a model vibration experiment in which a roller-type running bearing is provided on the outer periphery of a plurality of frames stacked on a vibration table, and the frame is supported by a columnar member that holds the running bearing so that it can run freely. A sheared soil tank is disclosed. Furthermore, Patent Document 3 describes a model vibration experiment in which a plurality of frames that are slidable in the vibration direction are stacked on a base, and the frames are supported by a pair of opposing walls with the frames in between. A sheared soil tank for use is disclosed. The frames constituting such a sheared soil tank are generally of the same planar shape and the same cross-sectional shape. Further, the bottom plate is often composed of a solid board without a hollow part.
By the way, since there is a limit to the weight that can be loaded on the shaking table, it is necessary to reduce the weight of the sheared soil tank in order to handle a larger capacity ground model.

JP2018-31628A Japanese Patent Application Publication No. 5-281081 Japanese Patent Application Publication No. 2001-74591

An object of the present invention is to propose a sheared soil tank for model vibration experiments that allows the weight of the sheared soil tank to be reduced without changing the excitation performance, and as a result, makes it possible to handle larger ground models. shall be.

The inventors installed a frame with a small vertical cross-sectional area on the upper side of a plurality of frames surrounding the ground model (constituting the sheared soil tank) to reduce weight as a sheared soil tank for model vibration experiments, or By providing a hollow part in the bottom plate, or by reducing the vertical cross-sectional area of the frame and having a hollow part in the bottom plate, it is possible to increase the size of the sheared soil tank without changing the vibration performance of the vibration device. The present invention was developed by focusing on the points that can be made.
The sheared soil tank for model vibration experiments of the present invention that solves these problems has a bottom plate installed on a shaking table and an inner surface installed in a frame shape in a plan view on the bottom plate so that they are flush with each other. and a plurality of laminated frames. This sheared soil tank for model vibration experiments includes a first frame part that is composed of a plurality of first frames that are installed on the bottom slab, and a first frame part that is installed above the first frame part. a second frame body section configured of a plurality of second frame bodies, which are the plurality of frame bodies to be installed, and the plurality of second frame bodies all have a uniform vertical cross-sectional area , or It has a vertical cross-sectional area that decreases toward the top, and has a vertical cross-sectional area that is smaller than the first frame.
The horizontal earth pressure acting on the sheared soil tank decreases continuously as it becomes shallower. Can be made smaller. For example, by making the cross-sectional area of the frame body smaller than that of other frames adjacent to the lower side, weight reduction can be achieved while suppressing deformation of the frame body. By doing this, it becomes possible to form a larger sheared soil tank, which in turn enables vibration experiments using a ground model with a larger volume. Specifically, if the capacity of the sheared soil tank is increased, a wider range of ground can be simulated, and as a result, dynamic ground characteristics closer to the actual situation can be reproduced.
In addition, by configuring the second frame portion from a plurality of frames that all have a uniform vertical cross-sectional area, or a plurality of frames whose vertical cross-sectional area becomes smaller toward the top, the sheared soil tank It becomes possible to achieve weight reduction. Note that in this specification, the frame body is defined as being composed of a first frame body part and a second frame body part installed above the first frame body part, but the first frame body part and the second frame body part are The second frame body portion may be constructed of members having the same cross-sectional area.
If the bottom plate has a hollow portion, it is lighter than a bottom plate made of a solid member. Therefore, it becomes possible to form a larger sheared soil tank, which in turn enables vibration experiments using a ground model with a larger volume.

According to the sheared soil tank for model vibration experiments of the present invention, it becomes possible to reduce the weight of the sheared soil tank, and in turn, it becomes possible to handle a ground model with a larger volume.

FIG. 2 is a perspective view showing an example of a sheared soil tank for model vibration experiments. It is a sectional view showing a sheared soil tank for model vibration experiments of the first embodiment. It is a figure which shows a bottom plate, Comprising: (a) is a top view, (b) is a sectional view. FIG. 2 is a schematic diagram showing an example of horizontal earth pressure acting on a sheared earth tank for model vibration experiments. It is a figure which shows the sheared soil tank for model vibration experiments of 2nd embodiment, (a) is sectional drawing, (b) is an enlarged sectional view which shows a part of frame. It is a figure which shows the bottom plate of the sheared soil tank for model vibration experiments based on another form, Comprising: (a) is a top view, (b) is a sectional view. It is a figure which shows the bottom plate of the sheared soil tank for model vibration experiments based on other forms, Comprising: (a) is a top view, (b) is a sectional view.

The present invention relates to a plurality of frames surrounding a ground model (constituting a sheared soil tank), in which a frame with a small vertical cross-sectional area is installed on the upper side, in which a hollow part is provided in the bottom plate, or in the above-mentioned frame. This is a sheared soil tank for model vibration experiments with a small vertical cross-sectional area and a hollow part in the bottom plate.
<First embodiment>
In this embodiment, a sheared soil tank 1 for model vibration experiments will be described, which is used as a test device for reproducing the behavior of the ground during an earthquake. The sheared soil tank 1 for model vibration experiments of this embodiment has a bottom plate 2 and a frame 3 that are lightweight and have sufficient rigidity and strength, thereby reducing the weight of the sheared soil tank 1 for model vibration experiments, and The size shall be maximized within the range that can be excited by the loading test equipment and shaking table test equipment.
FIG. 1 is a perspective view showing a sheared soil tank 1 for model vibration experiments, and FIG. 2 is a sectional view (AA sectional view in FIG. 1) of the sheared soil tank 1 for model vibration experiments of the first embodiment. As shown in FIG. 1, the sheared soil tank 1 for model vibration experiments includes a bottom plate 2 installed on a shaking table (not shown), and a plurality of frames 3, 3,... stacked on the bottom plate 2. It includes a support member 4 that supports the frame 3 in the vibration direction of the sheared soil tank or in the long side direction of the sheared soil tank. In addition, in order to prevent unexpected movement of the frame 3 surrounding the sheared soil tank during vibration, a fail-safe stopper 6 is provided on the side of the frame 3 where the support member 4 is not installed. . The sheared soil tank 1 for model vibration experiments is constructed with a membrane installed inside a plurality of frames 3, 3, ... stacked on a bottom plate 2, and after forming a soil model inside, a centrifugal loading experiment device and vibration Vibration is performed using a bench experimental device.

3(a) is a plan view of the bottom plate 2, and FIG. 3(b) is a sectional view of the bottom plate 2. As shown in FIG. 3(a), the bottom plate 2 has a rectangular shape in plan view. The bottom plate 2 of this embodiment has a plurality of hollow parts 21, 21, . The hollow portion 21 is formed below the area surrounded by the frame 3 (see FIG. 2). That is, the hollow part 21 is formed in the center part of the bottom plate 2, and the hollow part 21 is not formed in the edge part of the bottom plate 2. In this embodiment, a plurality of rows of hollow portions 21 are arranged in parallel at intervals in the longitudinal direction of the bottom plate 2 at intervals in the lateral direction. The hollow portion of this embodiment has a rectangular parallelepiped shape, as shown in FIGS. 3(a) and 3(b).

The frame body 3 has a rectangular shape in plan view, as shown in FIG. The frame body 3 is formed by installing square pipe-like members in a frame shape. As shown in FIG. 2, the sheared soil tank 1 for model vibration experiments of this embodiment is composed of a plurality of (four in this embodiment) frames 3, 3, . . . installed on a bottom plate 2. It includes one frame body part 31 and a second frame body part 32 configured of a plurality of (four in this embodiment) frame bodies 3, 3, . . . installed above the first frame body part 31. There is. The frame bodies 3 are stacked on the bottom plate 2 so that their inner surfaces are flush with each other. That is, the plurality of frames 3 are formed so that the area of the space surrounded by the frames is the same. On the other hand, the outer width (outer shape) of the frame 3 constituting the second frame portion 32 is smaller than the outer width (outer shape) of the frame 3 constituting the first frame 31 . That is, the frame 3 forming the second frame section 32 has a smaller vertical cross-sectional area than the frame 3 forming the first frame section 31. In this embodiment, by making the cross-sectional area of the frame 3 of the second frame part 32 smaller than the cross-sectional area of the frame 3 of the first frame part 31, weight reduction is achieved while suppressing deformation of the frame 3. .
Here, FIG. 4 is a schematic diagram showing an example of the horizontal earth pressure P acting on the sheared earth tank 1 for model vibration experiments. As shown in Figure 4, the horizontal earth pressure P acting on the sheared soil tank 1 (frame body 3) for model vibration experiments decreases as it becomes shallower (as it goes up), so the upper frame body 3 is lower than the lower frame body 3. The cross-sectional area can be made smaller than that of the frame body 3, and the rigidity and strength can be made smaller.

The support member 4 supports the frame 3. In this embodiment, as shown in FIG. 2, a pair of support members 4, 4 are erected on the upper surface of the bottom plate 2 so as to face each other with the frame 3 in between. The support member 4 is made of steel (for example, channel steel) and has a length that is greater than the sum of the heights of all the frames 3. The support member 4 supports the frame 3 by being in contact with the outer surface of the frame 3 (the outer surface parallel to the excitation direction among the four outer surfaces of the frame 3). A filler portion 41 is formed at the upper portion of the support member 4 in correspondence with the position of the second frame portion 32 . The filler portion 41 has a thickness equivalent to the difference between the thickness of the frame 3 of the first frame portion 31 and the thickness of the frame 3 of the second frame portion 32. 32 protrudes from the support member 4 so as to come into contact with the outer surface of the frame 3. The filler portion 41 may be formed integrally with the steel material that constitutes the support member 4, or may be formed by attaching a separate member (another steel material). Alternatively, the filler portion 41 may not be provided. The pair of support members 4, 4 are opposed to each other at intervals along the excitation direction of the centrifugal loading experimental device, and rollers (not shown) are installed between the plurality of frames 3 to form the frame. I support 3.

According to the sheared soil tank 1 for model vibration experiments of this embodiment, since the hollow part 21 is provided in the bottom plate 2, it is possible to reduce the weight of the bottom plate 2. Compared to the case where the bottom plate 2 is a solid member, it is possible to form a larger sheared soil tank 1 for model vibration experiments even with the same weight, and as a result, it is possible to conduct vibration experiments using a ground model with a larger volume. . Specifically, if the capacity of the sheared soil tank is increased, a wider range of ground can be simulated, and as a result, dynamic ground characteristics closer to the actual situation can be reproduced.

In addition, since the cross-sectional area of the frame 3 of the second frame part 32 is made smaller than the cross-sectional area of the frame 3 of the first frame part 31, further weight reduction of the sheared soil tank 1 for model vibration experiments is achieved. It is possible to achieve this goal. In conventional sheared earth tanks, the cross-sectional shape of all the frames 3 is set according to the rigidity and strength required for the frame 3 at the position where the horizontal earth pressure P is greatest (lowest stage). In the embodiment, the weight of the sheared soil tank 1 for model vibration experiments is reduced by reducing the cross-sectional area of the second frame portion 32 located above. By doing this, it becomes possible to form a larger sheared soil tank, which in turn enables vibration experiments using a ground model with a larger volume.
Further, in this embodiment, since the filler portion 41 that protrudes toward the frame body 3 is formed between the frame body 3 and the support member 4 on the upper side of the support member 4, the first frame body portion 31 The frame body 3 of the second frame body portion 32 having a smaller cross-sectional shape than the frame body 3 can be supported.

<Second embodiment>
In the second embodiment, similarly to the first embodiment, a sheared soil tank 1 for model vibration experiments, which is used as a test device for reproducing the behavior of the ground during an earthquake, will be described. The sheared soil tank 1 for model vibration experiments of the present embodiment has a bottom plate 2 and a frame 3 that are lightweight and have sufficient rigidity and strength, thereby reducing the weight of the sheared soil tank 1 for model vibration experiments. The size shall be maximized within the range that can be excited by the centrifugal loading experimental device.
FIG. 5(a) is a sectional view of a sheared soil tank 1 for model vibration experiments according to the second embodiment. As shown in FIG. 5, the sheared soil tank 1 for model vibration experiments includes a bottom plate 2 installed on a shaking table (not shown), and a plurality of frames 3, 3, ... stacked on the bottom plate 2. A support member 4 that supports the frame body 3 is provided. Note that the details of the bottom plate 2 are the same as those shown in the first embodiment, so a detailed explanation will be omitted.

As shown in FIG. 5(a), the frame body 3 consists of a hollow member having a frame shape in plan view. The frame 3 of this embodiment is formed into a frame shape by processing a square steel pipe. The sheared soil tank 1 for model vibration experiments of this embodiment includes a first frame part 31 configured of a plurality of (four in this embodiment) frames 3, 3, . . . installed on the bottom slab 2; A second frame part 32 is provided above the first frame part 31 and is configured of a plurality of (four in this embodiment) frames 3, 3, . . . . The frame bodies 3 are stacked on the bottom plate 2 so that the inner and outer surfaces thereof are flush with each other. That is, all the frames 3 have the same outer shape (the inner width and the outer width are the same). FIG. 5(b) is an enlarged sectional view showing the frame 3 at the boundary between the first frame portion 31 and the second frame portion 32. As shown in FIG. As shown in FIG. 5(b), the inner space area of the frame 3 of the second frame part 32 is larger than the inner space area of the frame 3 of the first frame part 31. That is, the frame 3 of the second frame part 32 is made of a square steel tube that is thinner than the frame 3 of the first frame part 31, so that the frame 3 of the first frame part 31 is It has a smaller longitudinal cross-sectional area. The plurality of frames 3 constituting the second frame part 32 of this embodiment all have a uniform vertical cross-sectional area, as shown in FIG. 5(a). By making the cross-sectional area of the frame body 3 of the second frame body part 32 smaller than the cross-sectional area of the frame body 3 of the first frame body part 31, weight reduction can be achieved while suppressing deformation of the frame body 3.

The support member 4 supports the frame 3. In this embodiment, as shown in FIG. 5(a), a pair of supporting members 4, 4 are erected on the upper surface of the bottom plate 2 so as to face each other with the frame 3 in between. The support member 4 is made of steel (for example, channel steel) and has a length that is greater than the sum of the heights of all the frames 3. The support member 4 supports the frame 3 by being in contact with the outer surface of the frame 3. The pair of support members 4, 4 face each other at intervals along the direction of application of the centrifugal loading experiment apparatus, and are supported slidably by the plurality of frames 3.
As shown in FIG. 5(b), rollers 5 are interposed between the frames 3. The rollers 5 reduce the frictional resistance between the frame bodies 3 and enable the frame body 3 to flexibly follow the shear deformation of the ground model without hindering it. Note that the roller 5 is also interposed between the frame 3 and the support member 4.

According to the sheared soil tank 1 for model vibration experiments of this embodiment, since the hollow part 21 is provided in the bottom plate 2, it is possible to reduce the weight of the bottom plate 2. Compared to the case where the bottom plate 2 is a solid member, it is possible to form a larger sheared soil tank 1 for model vibration experiments even with the same weight, and as a result, it is possible to conduct vibration experiments using a ground model with a larger volume. . If the capacity of the sheared soil tank 1 for model vibration experiments is increased, the size of the reduced model body can be made closer to the actual size, and as a result, dynamic ground characteristics closer to the actual situation can be reproduced.

Moreover, since the cross-sectional area of the frame 3 of the second frame body part 32 is made smaller than the cross-sectional area of the frame body of the first frame body part 31, the sheared soil tank 1 for model vibration experiments by the frame body 3 is further It is possible to reduce the weight. In conventional sheared earth tanks, the cross-sectional shape of all the frames 3 is set according to the rigidity and strength required for the frame 3 at the position where the horizontal earth pressure P is greatest (lowest stage). In the embodiment, the weight of the sheared soil tank 1 for model vibration experiments is reduced by reducing the cross-sectional area of the second frame portion 32 located above. By doing this, it becomes possible to form a larger sheared soil tank, which in turn enables vibration experiments using a ground model with a larger volume.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and each of the above-mentioned components can be modified as appropriate without departing from the spirit of the present invention.
In the above embodiment, the sheared soil tank 1 for model vibration experiments is composed of a bottom plate 2 having a hollow portion 21 and a plurality of frames 3 stacked on the bottom plate and whose cross-sectional area becomes smaller toward the upper side. However, the present invention is not limited to this, and the case where the frame body 3 has a uniform cross-sectional area and the bottom plate 2 has a hollow part 21, or a combination where the bottom plate 2 without the hollow part 21 and a plurality of frames 3 differ only in cross-sectional area. It may be.
For example, the shape of the hollow part 21 of the bottom plate 2 is not limited, and may be cylindrical, for example, as shown in FIGS. 6(a) and 6(b). Further, the number and arrangement of the hollow portions 21 are not limited, and may be arranged in a staggered manner, for example. Moreover, the hollow part 21 of the bottom plate 2 may have a honeycomb shape, as shown in FIGS. 7(a) and 7(b).
Further, in the embodiment, the hollow portion 21 is formed only in the center of the bottom plate 2, but the hollow portion 21 may be arranged over the entire surface of the bottom plate 2 as long as the strength of the bottom plate 2 can be ensured.

Furthermore, in the embodiment described above, the case where the sheared soil tank 1 for model vibration experiments is provided with the first frame part 31 and the second frame part 32 has been described, but the sheared soil tank 1 for model vibration experiments is It is not necessary to separate the frame body part 31 and the second frame body part 32. That is, the plurality of frames 3 of the sheared soil tank 1 for model vibration experiments may all have the same vertical cross-sectional area, or may differ depending on the height at which the frames 3 are arranged. For example, the plurality of frames 3 are configured such that the vertical cross-sectional area of each frame body 3 becomes smaller as it goes upward (the vertical cross-sectional area of each frame body 3 becomes smaller than the vertical cross-sectional area of other frame bodies 3 adjacent to the lower side). You may. Moreover, the plurality of frames 3 of the sheared soil tank 1 for model vibration experiments are not only provided with two types of the first frame part 31 and the second frame part 32, but are provided with three or more types of frames 3. Good too.
Furthermore, in the embodiment described above, a case has been described in which the vertical cross-sectional areas of the plurality of frames 3 constituting the second frame body part 32 are all the same, but the plurality of frames 3 constituting the second frame body part 32 are , the vertical cross-sectional area may be configured to gradually become smaller toward the top.
The method of fixing the support member 4 is also not limited. The support member 4 may be directly fixed to the bottom plate 2 or may be fixed to the bottom plate 2 via a jig or the like. Further, the support member 4 may be attached to a member provided on the vibration table without being fixed to the bottom plate 2.
The materials constituting each member of the sheared soil tank 1 for model vibration experiments (bottom plate 2, frame 3, support member 4, etc.) are not limited to steel as long as they exhibit the necessary strength and yield strength. , for example, an aluminum alloy.

1 Sheared soil tank for model vibration experiment 2 Bottom plate 21 Hollow part 3 Frame 31 First frame part 32 Second frame part 4 Support member 5 Roller

Claims (2)

A bottom plate installed on a shaking table,
A sheared soil tank for model vibration experiments, comprising a plurality of frames made of hollow members laminated so that their inner surfaces are flush with each other , which are installed in a frame shape in a plan view on the bottom plate,
a first frame body portion configured of a plurality of first frames that are the plurality of frames installed on the bottom plate;
a second frame body section configured of a plurality of second frame bodies that are the plurality of frame bodies installed above the first frame body part,
The plurality of second frames all have a uniform vertical cross-sectional area or a vertical cross-sectional area that becomes smaller toward the top, and each has a smaller vertical cross-sectional area than the first frame . A sheared soil tank for model vibration experiments, which is characterized by: The sheared soil tank for model vibration experiments according to claim 1 , wherein the bottom plate has a hollow part.

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