JP3783029B2 - Vibration control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionIs a systemRegarding the shaking method. The present inventionSystemThe vibration method is suitable for use in suppressing environmental vibration caused by railways, roads, construction sites, etc., and for earthquake countermeasures for buildings.
[0002]
[Prior art]
The inventor disclosed a ground reinforcement structure and a ground reinforcement construction method in Patent Document 1. The ground reinforcement structure disclosed in this document is a structure in which a plurality of sandbags are stacked in at least two layers in the vertical direction and are aligned in the horizontal direction, and each sandbag is tied with a string or wrapped with a sheet. Are substantially united.
[0003]
This ground reinforcement structure is less subsidence and exhibits high strength and great ultimate support. For this reason, if the ground reinforcement construction method that lays the ground reinforcement structure on the ground and forms the building on the ground reinforcement structure is adopted, even if the ground is weak, the building is strengthened. It becomes possible to support.
[0004]
The inventor has also found that such a ground reinforcing structure has a damping effect on traffic vibrations and seismic vibrations, installs such a ground reinforcing structure on the ground, and builds a building on the ground reinforcing structure. Also disclosed in the same document is a method for improving vibration damping properties. According to this vibration damping improvement method, it is possible to greatly improve the vibration damping of the building. The inventor also reported that the vibration of the building can be damped by arranging the sandbags in a substantially integrated state (Non-Patent Document 1).
[Patent Document 1]
JP 2000-80637 A
[Non-Patent Document 1]
Matsuoka Moto et al., “Measurement of vibration damping of buildings reinforced by“ Dono ””, 35th Geotechnical Engineering Conference (Gifu), June 2000, p. 1079-1080
[0005]
[Problems to be solved by the invention]
However, further improvements in damping performance are desired due to demands for suppression of environmental vibrations due to railways, roads, construction sites, etc. and earthquake countermeasures for buildings.
[0006]
  The present invention has been made in view of the above-described conventional situation, and can exhibit high vibration damping properties.SystemProviding a vibration method is an issue to be solved.
[0007]
[Means for Solving the Problems]
The inventors have intensively studied to solve the above problems. As a result, the conventional ground reinforcement structure was mainly intended to improve the bearing capacity of the building to be constructed on it, so each soil pad was substantially integrated with a string or the like. However, in order to further improve the vibration damping performance, it is rather preferable that each soil pad is laminated in an independent state rather than laminated in a substantially integrated state. It discovered and came to complete this invention.
[0008]
  That is, the present inventionIn the vibration damping method, a vibration damping structure is provided in the ground, and an oscillation source that generates vibration is provided on the vibration damping structure, whereby the vibration of the oscillation source is attenuated by the vibration damping structure, and the vibration damping structure is provided. A vibration control method for restricting propagation of vibration to the outside of a structure,
The vibration damping structure is formed by laminating at least two layers in the vertical direction in which a plurality of sandbags are independent of each other. Each sandbag is filled with a granular material and the granular material. It is a flat body made of a bag made of a material that can be bent by its own weight or external force and hardly stretched. The bag body is made of a woven fabric made of synthetic fiber or natural fiber, and the flat surface of each soil pad is substantially horizontal. It is characterized by being laminated.
Further, the vibration damping method of the present invention provides a vibration damping structure in the ground, and a stationary body on which the vibration is restricted is provided on the vibration damping structure, so that vibration is generated outside the vibration damping structure. When there is an oscillation source to emit, the vibration damping method attenuates the vibration by the damping structure, and restricts the propagation of the vibration to the stationary body on the damping structure,
The vibration damping structure is formed by laminating at least two layers in the vertical direction in which a plurality of sandbags are independent of each other. Each sandbag is filled with a granular material and the granular material. It is a flat body made of a bag made of a material that can be bent by its own weight or external force and hardly stretched. The bag body is made of a woven fabric made of synthetic fiber or natural fiber, and the flat surface of each soil pad is substantially horizontal. It is characterized by being laminated.
Furthermore, the vibration damping method of the present invention provides a vibration damping structure in the ground, and separates the oscillation source that generates vibration from a stationary body that desires to limit the vibration by the vibration damping structure. If there is an oscillation source that generates vibration outside the vibration structure, the vibration damping structure in the middle attenuates the vibration and limits the propagation of vibration to the other stationary body. A vibration control method,
The vibration damping structure is formed by laminating at least two layers in the vertical direction in which a plurality of sandbags are independent of each other. Each sandbag is filled with a granular material and the granular material. It is a flat body made of a bag made of a material that can be bent by its own weight or external force and hardly stretched. The bag body is made of a woven fabric made of synthetic fiber or natural fiber, and the flat surface of each soil pad is substantially horizontal. Are stacked likeIt is characterized by that.
[0009]
According to the test results of the inventors, the vibration damping structure of the present invention is a state in which the sandbags laminated in at least two layers in the vertical direction are independent from each other, so that it is difficult to propagate vibration from above downward, Conversely, vibrations from below are difficult to propagate upward. It is thought that each individual sandbag absorbs its vibrational energy by deforming itself minutely and exhibits damping properties. The minute deformation of the sandbag is caused by changing the positions of the individual particles packed in the sandbag while being restrained by the bag. At that time, the vibration energy is considered to be consumed by the frictional force because each particle changes its position with the frictional force generated between each other and the bag.
[0010]
For example, when an oscillation source that generates vibration is provided on a damping structure in which two or more sandbags are stacked in the vertical direction, each sandbag is stacked up and down by gravity. It is considered that the vibration energy is absorbed by deforming to the bottom, and the lower soil pits successively perform the same action.
[0011]
At this time, as in the past, if each soil cage is substantially united by a string or the like, a small deformation of the upper soil cage is limited by the lower soil cage connected by the string or the like, and the absorption rate of vibration energy It is thought that will be suppressed. In addition, if each soil cage is substantially united by a string or the like as in the prior art, the vibration energy reduced by the upper soil cage is propagated directly to the lower soil cage by the string or the like, and the upper and lower soil cages. It is also considered that the vibration energy cannot be reduced at the boundary. In contrast, the damping structure according to the present invention has independent upper and lower sandbags, so that the minute deformation of the upper sandbag is not limited by the lower sandbag and is considered to be able to effectively absorb vibration energy. It is done. In addition, since the upper and lower sandbags are independent, it is considered that the vibration energy can be reduced at the boundary between the upper and lower sandbags.
[0012]
Thus, the vibration damping structure of the present invention exhibits high vibration damping properties. For this reason, it becomes possible to satisfy more than ever the demands for suppression of environmental vibrations caused by railways, roads, construction sites, etc. and earthquake countermeasures for buildings.
[0013]
In the vibration damping structure of the present invention, it is preferable that the gap is filled with a filling material interposed in the gap between the sandbag and the sandbag. As the filling material, the same granular material as the filling material of clay can be adopted.
[0014]
The vibration damping structure of the present invention is preferably formed by horizontally aligning a plurality of sandbags. According to the test results of the inventors, the vibration damping structure of the present invention is difficult to propagate the vibration from the side to the side if the soil walls arranged in the horizontal direction are independent from each other. As described above, the individual sandbags are thought to be because they absorb vibration energy and exhibit damping properties by being deformed minutely themselves.
[0015]
For example, assuming a damping structure in which two or more layers of sandbags are stacked in the vertical direction and aligned in the horizontal direction, and an oscillation source for generating vibration is provided on the damping structure, the damping If the upper sandbag of the structure is placed across multiple sandbags of the lower layer, the upper sandbag itself absorbs its vibrational energy by being deformed minutely, and the lower and horizontal sandbags in turn. This is considered to be due to the similar effect.
[0016]
  On the other hand, for example, assuming a damping structure in which a plurality of sandbags are laminated in the vertical direction and are aligned in the horizontal direction, and an oscillation source for generating vibration is provided on the damping structure, The upper sandbag of the damping structure straddles multiple lower sandbagsWithoutIs placedRuIf so, according to the test results of the inventors, the horizontal vibration does not directly propagate to the sandbag in contact with the horizontal direction. In this case, regardless of whether the horizontal sandbags are in contact with each other or not, the horizontal sandbags only generate the same degree of vibration. In a structure consisting of sandbags stacked on the top and bottom of a damping structure provided with an oscillation source, vibration is attenuated to the bottom surface of the block, and only weak vibration is applied to the adjacent block through the ground where the bottom surface is in contact with gravity. It will not be propagated.
[0017]
In these cases, if the soil sandbags are substantially united by a string or the like as in the conventional case, minute deformation of the sandbag is limited by the sandbag next to the string, and vibration energy is reduced. It is thought that the absorption rate is suppressed. In addition, when each soil bag is substantially united by a string or the like as in the prior art, the vibration energy reduced by the side soil bag propagates to the side soil bag as it is by the string or the like. It is thought that the vibration energy cannot be reduced at the boundary of the sandbag. On the other hand, in the vibration damping structure of the present invention, since the left and right sandbags are independent, the minute deformation of the horizontal sandbag is not limited by the side sandbag and can effectively absorb vibration energy. Conceivable. Moreover, since the left and right sandbags are independent, it is considered that the vibration energy can be reduced at the boundary between the left and right sandbags.
[0018]
For this reason, it is preferable that the upper sandbag is placed across a plurality of lower sandbags without being integrated, such as by connecting with a string or the like. For example, when an oscillation source that generates vibration is provided on the vibration damping structure, the oscillation of the oscillation source can be extremely reduced in a lower layer and at a position further away in the horizontal direction. Moreover, this can improve the bearing capacity of the vibration damping structure and the building that can be constructed on this.
[0019]
It is not always necessary that all the sandbags constituting the vibration damping structure of the present invention have substantially the same shape. However, if the plurality of sandbags have substantially the same shape, it is easy to predict the damping performance of the damping structure of the present invention. In addition, if a plurality of sandbags have substantially the same shape, mass production of bags constituting the sandbags becomes possible, and the production cost of the sandbags and eventually the damping structure or the cost of construction that embodies the damping method can be reduced. In terms of surface.
[0020]
When each soilbag has substantially the same shape, the upper soilbag can be placed across the two lower soilbags almost equally. In this case, the vibrations of the upper sandbag are regularly distributed to the two lower sandbags while being damped by the boundary between the sandbag and the lower sandbag. Thereby, it is possible to improve the vibration control performance predictably. Moreover, since each sandbag has substantially the same shape, it is preferable in terms of the production cost or construction cost of the sandbag, and hence the damping structure. Furthermore, this can improve the supporting force of the vibration damping structure and the building that can be constructed on the vibration damping structure.
[0021]
In addition, when the respective sandbags have substantially the same shape, the upper sandbag can be placed almost equally across the four lower sandbags. In this case, the vibrations of the upper sandbag are regularly distributed to the four lower sandbags while being damped by the boundary between the sandbag and the lower sandbag. Thereby, it is possible to further greatly improve the vibration control performance in a predictable manner. Moreover, since each sandbag has substantially the same shape, it is preferable in terms of the production cost or construction cost of the sandbag, and hence the damping structure. Furthermore, this can improve the supporting force of the vibration damping structure and the building that can be constructed on the vibration damping structure.
[0022]
In the present invention, each sandbag means a granular material and a bag made of a material that is filled with the granular material and can be bent by its own weight or an external force and is difficult to stretch.
[0023]
The granular materials used as filling materials for sandbags are: (1) natural granular materials such as soil, sand, gravel, and volcanic deposits; (2) crushed stone, concrete waste, asphalt waste, tile waste, tile waste, charcoal waste, etc. Processed granular material processed from natural products and artificial materials, granular materials after heat treatment of slag, etc., (3) plastic particles such as EPS (styrene foam), metal particles, ceramic balls, glass balls, etc. Things can be adopted. If we use locally generated soil such as soil, sand, gravel, and crushed stone as granular materials, we can obtain a sandbag just by bringing the bag to the site and filling the locally generated soil in the bag. , Can reduce the cost of carrying sandbags. If construction waste materials such as concrete waste materials, asphalt waste materials, tile waste materials, and tile waste materials are adopted as granular materials, effective use of building waste materials can be realized. If the charcoal granular material is adopted, the sandbag can be reduced in weight, and high water permeability and water purification characteristics can be imparted. If a light-weight granular material such as EPS (styrene foam) is adopted, it is possible to reduce the weight of the sandbag. If volcanic deposits are adopted as granular materials, effective use of volcanic deposits that are in need of disposal will be realized.
[0024]
  The bag body is a bag made of a material which is filled with a granular material and can be bent by its own weight or an external force and hardly stretched. As bags, weaves made of synthetic fibers such as polyethylene, polypropylene, polyester, and natural fibersClothAdoptTheIt is preferable to employ a bag made of an inexpensive polyethylene or polypropylene woven fabric. With this bag body, sandbags exhibit excellent durability even in the presence of water such as groundwater, as long as sunlight (ultraviolet rays) is cut off.
[0025]
The particle size of the granular material can be appropriately selected depending on the fineness of the eyes when the bag is a woven fabric or a non-woven fabric. However, it is preferable that the granular material has two or more particle sizes. If the granular material has a single particle size, the contact between the individual particles is reduced and the gaps between the individual particles are relatively large, so the frictional force generated between the individual particles is reduced, There is concern in terms of vibration control. On the other hand, if the granular material has two or more particle sizes, the contact between the individual particles increases and the gap between the individual particles becomes relatively small. The force is increased, which is preferable in terms of vibration damping. In addition, when the vibration control structure is provided in the ground, if the granular material has a coarse and large particle diameter, it is easy to prevent the moisture in the ground from rising up by the surface tension. It also demonstrates the waterproofing effect of buildings built in and the anti-freezing effect in cold regions.
[0027]
The vibration damping method of the present invention is characterized in that the vibration damping structure is provided in the ground, and an oscillation source for generating vibration is provided on the vibration damping structure.
[0028]
According to this vibration damping method, the vibration of the oscillation source can be damped by the vibration damping structure, so that propagation of vibration to the outside of the vibration damping structure can be limited. This vibration damping method can be embodied by a form in which these oscillation sources are constructed on the vibration damping structure when, for example, railways, roads, construction sites, and the like correspond to the oscillation sources.
[0029]
The vibration damping method of the present invention is characterized in that the vibration damping structure is provided in the ground, and a stationary body that is desired to limit vibration is provided on the vibration damping structure.
[0030]
According to this vibration suppression method, even if there is an oscillation source that generates vibration outside the vibration suppression structure, the vibration can be attenuated by the vibration suppression structure. Propagation can be limited. This vibration damping method can be embodied by a form in which a building such as a residence is constructed on a vibration damping structure when, for example, a track, a road, a construction site, or the like corresponds to the oscillation source. It is also effective to construct a building such as a residence on the damping structure in preparation for a future earthquake.
[0031]
Furthermore, the vibration damping method of the present invention is characterized in that the vibration damping structure is provided in the ground, and an oscillation source that generates vibration and a stationary body that desires to limit the vibration are separated by the vibration damping structure. To do.
[0032]
According to this vibration suppression method, even if there is an oscillation source that generates vibration outside the vibration suppression structure, the vibration can be attenuated by the intermediate vibration suppression structure as a barrier. The propagation of vibrations to the body can be limited. This vibration damping method can be embodied by a form in which a vibration damping structure is constructed between the oscillation source and a building such as a residence when, for example, railways, roads, construction sites, and the like correspond to the oscillation source. It is also effective to construct a damping structure around a building such as a residence in preparation for a future earthquake.
[0033]
The oscillation source emits vibrations, and includes the above-mentioned railways, roads, construction sites, earthquake sources, machines that generate vibrations, and the like. In addition, the stationary body is intended to limit vibration, and includes a machine that does not like vibration in addition to the building such as the house. The underground includes not only the soil and sand but also the concrete that is the foundation laid in the ground.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments 1 to 4 embodying the present invention will be described below with reference to the drawings.
[0035]
(Embodiment 1)
In Embodiment 1, the inventor, Matsuoka Gen, confirmed the effect of reducing the vibration load by the damping structures D1 to D4 shown in FIG. 1 and FIGS. In other words, when multiple sandbags are stacked in the vertical direction at the bottom of the building independently, and aligned in the horizontal direction, the supporting force of the building is increased and environmental vibration such as traffic vibration is reduced. To do. Here, the results of several indoor vibration measurement experiments conducted to investigate such a vibration reduction mechanism targeting such a vibration damping structure D1 are shown.
[0036]
"Test 1"
FIG. 1 is an investigation of the vibration reduction effect in the vertical direction of a vibration control structure D1 in which soil bags 1 to 5 are stacked in five layers in the vertical direction on the ground B made of concrete. Each of the sandbags 1 to 5 includes a granular material made of sand and gravel, and a bag body that is a polyethylene woven fabric filled with the granular material. The dimensions of each sandbag 1-5 are 40 cm in length, 40 cm in width, and 8 cm in height. The granular material has a particle size of sand and gravel.
[0037]
As shown in the drawing, four small strain gauge type acceleration sensors (measurement of acceleration in the vertical direction) C1 to C4 are sandwiched between the sandbags 1 to 5 in order from the bottom. Further, an oscillation source V that generates vibration at a certain acceleration is placed on the uppermost sandbag 5. The oscillation source V is an electric plate compactor (mass 28 kg, frequency 6 Hz) used for compaction of the roadbed.
[0038]
In this case, when the oscillation source V generates vibration at an acceleration of 523 gal, the uppermost sensor C4 measures vibration at an acceleration of 355 gal, and the lower sensor C3 measures vibration at an acceleration of 195 gal. The sensor C2 measured vibration at an acceleration of 124 gal, and the sensor C1 below it measured vibration at an acceleration of 46 gal. From this result, it can be seen that the acceleration is reduced to about half each time one piece of earthenware 1 to 5 is transmitted. For example, it can be seen that the acceleration is reduced at a rate of 50% × 50% × 50% ≈13% from the upper surface of the sandbag 4 of the fourth layer from the bottom to the lower surface of the sandbag 2 of the second layer from the bottom.
[0039]
On the other hand, as shown in FIG. 2, in order to make the boundary between the upper and lower soil pads 1 to 5 free, the granular material filled in each soil soil 1 to 5 is packed in a cardboard box 6 at a height of 32 cm, and the same as above. A test was conducted. Only one sandbag 5 was placed on the granular material with the sensor C4 interposed therebetween. Further, in the granular material, three sensors C1 to C3 are provided for every 8 cm, similarly to the heights of the sandbags 1 to 5. The length and width of the cardboard box 6 are 55 cm.
[0040]
In this case, when the oscillation source V generates vibration at an acceleration of 788 gal, the uppermost sensor C4 measures vibration at an acceleration of 173 gal, and the lower sensor C3 measures vibration at an acceleration of 147 gal. The sensor C2 measured vibration at an acceleration of 119 gal, and the sensor C1 below it measured vibration at an acceleration of 99 gal. From this result, it can be seen that the acceleration is reduced only by 57% even if 8 cm × 3 = 24 cm apart only by packing the granular material in the cardboard box 6.
[0041]
On the other hand, as shown in FIG. 3, in order to further free the boundaries between the upper and lower soil pads 1 to 5, the same granular pile was built with a height of 32 cm, a peak width of 60 cm, and a hem width of 150 cm, and the same test as above. Was done. Only one sandbag 5 was placed on the top of the granular pile with the sensor C4 interposed therebetween. Further, three sensors C1 to C3 are provided for every 8 cm in the inside of the pile of the granular material, similarly to the heights of the sandbags 1 to 5.
[0042]
In this case, when the oscillation source V generates vibration at an acceleration of 774 gal, the uppermost sensor C4 measures the vibration at an acceleration of 290 gal, and the lower sensor C3 measures the vibration at an acceleration of 199 gal. The sensor C2 measured vibration at an acceleration of 136 gal, and the sensor C1 below it measured vibration at an acceleration of 113 gal. From this result, it is understood that the acceleration is reduced only by 39% within 8 cm × 3 = 24 cm only by making the granular material a mountain.
[0043]
It can be seen that the vibration damping structure D1 shown in FIG. 1 reduces vibrations four times or more compared to the structure shown in FIG. 2 and three times compared to the structure shown in FIG. One reason for this is that when each soilbag 1-5 receives vertical vibrations, the soilbags 1-5 themselves flatten or return (expand or shrink) to cause a slight deformation. I think it is because it is easy to attenuate energy. This will be understood, for example, when the oscillation source V is placed on a concrete plate, rather than the vibration being amplified. Thus, the suppleness of the sandbags 1 to 5 has various advantages.
[0044]
"Test 2"
FIGS. 4 to 7 show a structure in which a block B1 in which four layers of sandbags 11 to 14 are stacked on a concrete ground B and a block B2 in which four layers of sandbags 21 to 24 are stacked in the vertical direction are adjacent to each other. Vibration structures D2 and D3 are prepared, and vibration experiment results for examining the horizontal vibration reduction effect of the respective sandbags 11 to 14 and 21 to 24 are shown. As shown in the figure, three sensors C11 to C13 similar to those described above are sandwiched between the sandbags 11 to 14 in order from the bottom of the block B1. On the top of the sandbag 14 of the block B1, a 60 Hz oscillation source V1 or a 6 Hz oscillation source V2 is placed. The oscillation sources V1 (mass 25 kg) and V2 (mass 28 kg) are electric plate compactors used for compaction of the roadbed. On the other hand, three sensors C21 to C23 are sandwiched between the sandbags 21 to 24 in order from the bottom of the block B2, and the sensor C24 is placed on the sandbag 24 of the uppermost layer. The respective sandbags 11 to 14 and 21 to 24 are the same as those in Test 1 above.
[0045]
In the vibration damping structure D2 shown in FIG. 4, both blocks B1 and B2 are brought into contact with each other in the horizontal direction, and a 60 Hz oscillation source V1 is placed on one block B1. In the vibration damping structure D3 of FIG. 5, the 60 Hz oscillation source V1 is placed on one block B1 without bringing both blocks B1 and B2 into contact with each other in the horizontal direction. In the vibration damping structure D2 of FIG. 6, both blocks B1 and B2 are brought into contact in the horizontal direction, and a 6 Hz oscillation source V2 is placed on one block B1. In the vibration damping structure D3 of FIG. 7, the 6 Hz oscillation source V2 is placed on one block B1 without bringing both blocks B1 and B2 into contact with each other in the horizontal direction. In any of the damping structures D2 and D3, a plurality of sandbags 11 to 14, 21, and 24 are stacked in two or more layers in the vertical direction and aligned in the horizontal direction. It is not placed across a plurality of sandbags S.
[0046]
In the vibration suppression structure D2 of FIG. 4, when the oscillation source V1 generates vibration with an acceleration of 9036 gal, the uppermost sensor C13 of the block B1 measures the vibration with an acceleration of 15464 gal, and the lower sensor C12 has 7777 gal. The vibration was measured at an acceleration of 4302 gal in the sensor C11 below. The sensor C24 at the top of the block B2 measures vibration at an acceleration of 490 gal, the sensor C23 below it measures vibration at an acceleration of 167 gal, the sensor C22 below it measures vibration at an acceleration of 59 gal, In the lower sensor C21, vibration was measured at an acceleration of 49 gal.
[0047]
In the vibration damping structure D3 of FIG. 5, when the oscillation source V1 generates vibration at an acceleration of 9457 gal, the uppermost sensor C13 of the block B1 measures the vibration at an acceleration of 15053 gal, and the sensor C12 below it. The vibration was measured with an acceleration of 8467 gal, and the vibration was measured with the acceleration of 3949 gal in the sensor C11 below. In addition, the sensor C24 at the top of the block B2 measures vibration at an acceleration of 480 gal, the sensor C23 below it measures vibration at an acceleration of 167 gal, the sensor C22 below it measures vibration at an acceleration of 69 gal, In the lower sensor C21, vibration was measured at an acceleration of 49 gal.
[0048]
On the other hand, in the damping structure D2 of FIG. 6, when the oscillation source V2 generates vibration at an acceleration of 598 gal, the uppermost sensor C13 of the block B1 measures the vibration at an acceleration of 353 gal, and the sensor C12 below it. The vibration was measured at an acceleration of 167 gal, and the vibration was measured at an acceleration of 88 gal in the sensor C11 below. The sensor C24 at the top of the block B2 measures vibration at an acceleration of 29 gal, the sensor C23 below it measures vibration at an acceleration of 19 gal, the sensor C22 below it measures vibration at an acceleration of 10 gal, The sensor C21 below it also measured vibrations with an acceleration of 10 gal.
[0049]
In the vibration damping structure D3 of FIG. 7, when the oscillation source V2 generates vibration at an acceleration of 637 gal, the uppermost sensor C13 of the block B1 measures the vibration at an acceleration of 402 gal, and the sensor C12 below it. The vibration was measured with an acceleration of 176 gal, and the vibration was measured with an acceleration of 86 gal in the sensor C11 below. The sensor C24 at the top of the block B2 measures vibration at an acceleration of 29 gal, the sensor C23 below it measures vibration at an acceleration of 19 gal, the sensor C22 below it measures vibration at an acceleration of 10 gal, The sensor C21 below it also measured vibrations with an acceleration of 10 gal.
[0050]
From these results, it can be seen that even if the sandbags S do not contact each other, the vibration is transmitted to the horizontal sandbag S, which means that the vibration is transmitted through the ground B under the blocks B1 and B2. Yes. Therefore, in order to subtract the acceleration of the horizontal sandbag S transmitted through the ground B, the block B2 in the damping structure D3 in FIGS. 5 and 7 is obtained from each measured value in the block B2 in the damping structure D2 in FIGS. Subtract each measured value. Then, in the damping structure D2 of FIG. 4, the uppermost sensor C24 of the block B2 is +10 gal, the lower sensor C23 is ± 0 gal, the lower sensor C22 is −10 gal, and the lower sensor C21 is ± 0 gal. There is only a difference. Further, in the vibration damping structure D2 of FIG. 6, ± 0 gal for the uppermost sensor C24 of the block B2, ± 0 gal for the lower sensor C23, ± 0 gal for the lower sensor C22, and ± 0 gal for the lower sensor C21. The difference is 0 gal.
[0051]
From this result, it is considered that the slight difference in the damping structure D2 of FIG. 4 is an error in a range of ± 1% by a 1G (980 gal) strain gauge type acceleration sensor. As a result, it can be seen that vibration is not directly transmitted directly from the block B1 on which the oscillation sources V1, V2 are mounted to the sandbag S of the horizontal block B2, even if they are in contact. In the vibration damping structure D2 of FIG. 4, when a cup filled with water is placed on the block B1 on which the oscillation sources V1 and V2 are placed, the water is shaken vigorously so that the water is likely to jump out of the cup. On the block B <b> 2, the water surface was slightly formed on the water surface in the cup. Not only touching with bare hands but also cheeking, the vibration reduction was clear. This is an extremely interesting experimental fact that reminds us that even if it is a large earthquake, you will not feel vibration if you are on a helicopter.
[0052]
“Test 3”
  FIG. 8 shows a state of vibration reduction of the vibration control structure D4 in which a plurality of sandbags S are staggered on the ground B made of concrete. Each of the sandbags S has substantially the same shape, and the upper sandbag S of the third or higher layer from the bottom is placed substantially equally over the two lower sandbags S. In this vibration damping structure D4, as shown in FIG.2Two sensors C31, C32, C33, and C34 similar to the above are provided on the lower surface of the sandbags 31 and 32 that are aligned horizontally in the layer, and the sandbag 33 that spans the sandbags 31 and 32 in the third layer from the bottom. Two sensors C35 and C36 are provided on the lower surface of the sandbag, and one sensor C37 is provided on the lower surface of the sandbag 34 aligned in the horizontal direction with the sandbag 33, and straddles the sandbags 33 and 34 in the fourth layer from the bottom. Two sensors C38 and C39 are provided on the lower surface of the sandbag 35, and one sensor C40 is provided on the lower surface of the uppermost sandbag 36. Sensors C40, C39, C37, and C34 are located in the same vertical direction, sensors C38, C36, and C33 are located in the same vertical direction, and sensors C35 and C32 are located in the same vertical direction. A 6 Hz oscillation source V2 is placed on the uppermost sandbag 36. Each sandbag S is the same as in the tests 1 and 2 above.
[0053]
In this case, the sensor C40 measured vibration at an acceleration of 328 gal. The lower sensor C39 measured vibration with an acceleration of 205 gal, the lower sensor C37 measured vibration with an acceleration of 93 gal, and the lower sensor C34 measured vibration with an acceleration of 43 gal. The sensor C38 adjacent to the sensor C39 measured vibration at an acceleration of 64 gal, the sensor C36 below it measured vibration at an acceleration of 34 gal, and the sensor C33 below it measured vibration at an acceleration of 25 gal. Further, vibration was measured at an acceleration of 22 gal at the sensor C35 adjacent to the sensor C36, and vibration was measured at an acceleration of 9 gal at the sensor C32 below the sensor C35. In the sensor C31 adjacent to the sensor C32, vibration was measured at an acceleration of 10 gal.
[0054]
Here, from the result of Test 1, it is assumed that 50% vibration is reduced for each layer of sandbag S having a height of 8 cm in the vertical direction, and about 20 cm away in the horizontal direction, and 40% is reduced. Estimate the situation. In addition, from the result of the test 2, it is assumed that vibration is not directly transmitted between the sandbags S adjacent to each other. Thus, 328 gal of the sensor C40 is set as a starting point, and 164 gal, 82 gal, and 41 gal are halved for each layer of the sandbag S in the vertically downward direction. It was set as 33 gal and 16 gal in half. Hereinafter, it can be easily calculated in the same manner. It is interesting to compare the measured value of the vibration damping structure D4 in FIG. 8 with the estimated value, and it is found that they almost correspond to each other within the above-mentioned sensor error range.
[0055]
From the above vibration measurement results, it was found that the individuality of the sandbag S (which is a disjointed bag) and flexibility (flexibility) are advantageous, and it has a very specific vibration reduction effect. If these advantages are utilized well, a useful vibration reduction method can be created.
[0056]
(Embodiment 2)
In the second embodiment, the inventor Matsuoka, who is the inventor, uses the extremely effective vibration reducing effect of the vibration damping structures D5 to D7 shown in FIGS. A vibration reduction method based on the relationship is proposed. And the effectiveness of the vibration reduction method using said damping structure D5-D7 was confirmed by the vibration measurement in the construction site using real sandbag S. FIG.
[0057]
1. Countermeasure work at the oscillation source
(A) Construction overview
9 (A) and 9 (B) show construction outline diagrams of the damping structure D5 for the purpose of suppressing vibrations at the oscillation source. A plurality of sandbags S using locally generated soil as a granular material are prepared, and four layers (8 rows × 8 columns, 9 rows × 9 columns, 10 rows × 10 columns, these are arranged in a staggered manner on the ground B made of soil, (11 rows x 11 columns) Stacked damping structures were constructed. The upper sandbag S is placed so as to straddle the four lower sandbags S. The dimensions of each sandbag S are 40 cm in length, 40 cm in width, and 10 cm in height. Since the granular material is locally generated soil, it has two or more particle sizes.
[0058]
The oscillation source V was installed on the vibration control structure D5, and the vibration level meter was moved by 40 cm along the measurement lines shown in FIGS. 9A and 9B, and measurement was performed. The oscillation source V is an engine type plate compactor (mass 60 kg, vibration frequency 90 Hz) used for compaction of the roadbed.
[0059]
(B) Measurement result
The vibration measurement result is shown in FIG. The solid line is the result of measuring the distance attenuation of the original ground B immediately next to the place where the damping structure D5 is constructed. From FIG. 10, the vibration attenuation by the oscillation source V on the damping structure D5 is larger than the distance attenuation of the original ground B. Furthermore, a significant difference of 10 dB or more occurred in the vibration level where the vibration control structure D5 was passed to the original ground B. From this result, it can be seen that there is a very effective vibration reduction effect when the oscillation source V is directly mounted on the vibration damping structure D5 for oscillation.
[0060]
2. Countermeasure work in the propagation path
(A) Construction overview
As a method of blocking the vibration in the propagation path, countermeasures shown in FIGS. 11A and 11B were constructed. Three layers of sandbag S are stacked in a staggered position at a depth of 60 cm from the surface of the ground B made of soil (9 rows × 9 columns, 10 rows × 10 columns, 11 rows × 11 columns), and the first damping structure d61 is installed. Furthermore, in order to cut off the vibration transmitted by the surface wave, three layers of sandbag S are stacked on the surface of the ground B (2 rows x 8 columns, 3 rows x 8 columns, 4 rows x 8 columns) as a barrier. The second vibration damping structure d62 is arranged. In this way, the damping structure D6 composed of the first damping structure d61 and the second damping structure d62 was constructed.
[0061]
Moreover, as shown in FIGS. 12A and 12B, three layers of sandbag S are stacked in a staggered position at a depth of 30 cm from the surface of the ground B made of soil (2 rows × 8 columns, 3 rows × 8 Column, 4 rows × 8 columns), and only the second damping structure D7 as a barrier was disposed.
[0062]
As the oscillation source V, the same engine type plate compactor (mass 60 kg, vibration frequency 90 Hz) was used. The measuring instrument used a vibration level meter, and moved it 40 cm at a time for measurement.
[0063]
(B) Vibration measurement result
FIG. 13 shows the vibration measurement result of the countermeasure work in the propagation path. Here, the plot shown by the solid line is the case where the second damping structure d62 of the countermeasure work shown in FIG. 11 is removed, and only the soil having a thickness of 30 cm is constructed on the first damping structure d61. It is a measurement result. This was compared as the distance attenuation of ground B. From FIG. 13, the vibration is greatly attenuated at the position that exceeds the second damping structure d62 and moves to the original ground B. Compared to the case of soil alone, the second damping structure d62 is constructed. More effective vibration reduction effect was obtained.
[0064]
Moreover, the vibration measurement result at the time of constructing only 2nd damping structure D7 is shown in FIG. Here, the measurement was performed when the oscillation source V was separated from the second damping structure D7 by (1) 80 cm and (2) by 120 cm, but in either case, the second damping structure D7 was measured. After passing, the vibration level was greatly reduced, and a measured value which was 10 dB lower than the distance attenuation of the ground B was obtained at a distance of several meters from the countermeasure work. From the above, it was confirmed that it is effective to place a damping structure in the propagation path when performing countermeasures aimed at intermediate vibration isolation.
[0065]
(Embodiment 3)
The damping structure has a very effective vibration reducing effect. Therefore, in the third embodiment, inventor Matsuoka, who was the inventor, conducted a full-scale experiment on a test road in order to apply it to the field of traffic vibration. As a result, it was found that a high vibration reduction effect was exhibited by installing the damping structure on the lower roadbed (or upper roadbed) and providing the damping structure that blocks surface waves. This time, instead of traffic vibration, electric and engine type plate compactors were used as oscillation sources.
[0066]
1. Examination of countermeasures
Before conducting the experiment on the test road, a vibration control structure was constructed as an anti-vibration countermeasure for vertical stacking and staggered stacking to examine the countermeasures, and vibration measurements were made.
[0067]
(A) Construction outline and vibration measurement results of vertical piled damping structure
First, the damping structure D8 shown in FIG. 15 was constructed and vibration measurement was performed. In this vibration damping structure D8, in order to block the vibration propagating vertically downward, four layers of soil cover S are formed at a depth of 24 cm from the ground surface of the soil ground B (7 rows × 7 columns, 7 rows × 7 columns). It installed and it was set as the 1st damping structure d81. Furthermore, in order to cut off the vibration propagating in the horizontal direction, a vertical three-layer pile of sandbags S is arranged in a U shape in two rows or two columns on the first damping structure d81, and the second damping structure d82 (hatched portion in FIG. 15). The dimensions of each sandbag S are 40 cm in length, 40 cm in width, and 8 cm in height. Since the granular material is locally generated soil, it has two or more particle sizes.
[0068]
As the oscillation source V, an engine type plate compactor (mass 60 kg, frequency 90 Hz) and an electric plate compactor (mass 25 kg, frequency 60 Hz) were used. As shown in FIG. 15, the vibration is generated at the center of the countermeasure work, the measurement lines are taken in the three horizontal directions with the second damping structure d82 interposed therebetween, and the vibration propagated in each direction is measured by the vibration level meter. Measured with The vibration was regarded as a steady vibration, and measurement was performed while moving one sensor 40 cm from the vibration source along the measurement line.
[0069]
FIG. 16 shows a vibration measurement result when an electric plate compactor is used as the oscillation source V. The solid line is the distance attenuation value of the ground B measured in the immediate vicinity of the countermeasure work. Since the vertically stacked second vibration damping structure d82 is constructed in a U-shape, measurement was performed by measuring lines in three directions as shown in FIG. Comparing the case of oscillation from the countermeasure work with the distance attenuation of the ground B, it can be seen that the vibration level is greatly reduced from the vicinity of the second damping structure d82 in any of the three measurement lines. At a distance of several meters from the countermeasure work, a large difference of over ten dB was observed.
[0070]
(B) Outline of construction and vibration measurement results of staggered damping structure
  Next, as shown in FIG.SystemA vibration structure D9 was constructed and vibration measurement was performed. In this damping structure D9, the same first damping structure as the first damping structure d81 is used.d91, the shape of the second damping structure d92 is changed to a three-layer stack (7 rows x 2 columns, 7 rows x 3 columns, 7 rows x 4 columns from the top) in a staggered arrangement, Instead, it was a straight type. The measurement was performed under the same conditions as in the case of the vertically-damped second damping structure d82.
[0071]
The vibration measurement results in the case of the staggered second vibration damping structure d92 are shown in FIGS. FIG. 18 shows a vibration measurement result when using an electric plate compactor, and FIG. 19 shows a vibration measurement result when using an engine type plate compactor. From FIG. 18 and FIG. 19, it can be seen that, similarly to the case of vertical stacking, the vibration level is greatly reduced from the vicinity exceeding the second vibration damping structure d92. In the case of the electric plate compactor, about 15 dB, and in the case of the engine type plate compactor having a larger vibration than the electric type, the vibration was reduced by about 10 dB and the distance attenuation of the ground B.
[0072]
2. Experiment on test road
(A) Construction overview
Based on the experimental results described so far, a full-scale experiment was conducted on the test road. Assuming that it is constructed near the surface layer of the road, as shown in FIG. 20, four layers of sandbags S are vertically stacked at a depth of 20 cm from the surface of the ground B made of soil, and the first damping structure d101 It was. From the above experimental results, the second damping structure d102 was arranged in a staggered manner, and two layers (7 rows × 2 columns, 7 rows × 3 columns from the top) were installed so as to reach the ground surface. In this way, the damping structure D10 including the first damping structure d101 and the second damping structure d102 was constructed.
[0073]
As the oscillation source V, the engine type plate compactor described above was used. The measurement was performed by fixing the position of the oscillation source V and moving the vibration level meter every 40 cm.
[0074]
Furthermore, assuming that only surface waves are cut off in the middle, as shown in FIG. 12, the sandbag S is arranged in a staggered arrangement from the ground surface in three layers (7 rows × 2 columns, 7 rows × 3 columns, 7 rows × 7 rows from the top). The second damping structure D7 arranged only in (four rows) was also constructed and vibration measurement was performed.
[0075]
(B) Vibration measurement result
FIG. 21 and FIG. 22 show vibration measurement results when an engine type plate compactor is used as the oscillation source V. FIG. FIG. 21 shows the measurement results of the first and second damping structures d101 and d102, and FIG. 22 shows the measurement results of only the second damping structure D7. The solid line is the vibration measurement result at the part (without sandbag S) constructed under normal construction conditions on the same test road as the place where the countermeasure work was performed, and this was the distance attenuation.
[0076]
Compared with the distance attenuation, the vibration oscillated from the countermeasure work shows a larger attenuation characteristic than the distance attenuation after passing through the second damping structure D102. In particular, as shown in FIG. 22, it is interesting that only the second damping structure D7 arranged in a zigzag manner in three layers near the ground surface is attenuated by about 5 dB.
[0077]
3. Summary
From the above experiments, the effectiveness of anti-vibration measures using sandbags against vibration was confirmed. Since the construction shape of the sandbag S can be freely changed, it is possible to expect a greater effect as a vibration isolator by performing construction according to the site so that the sandbag S is arranged in the vibration propagation path. The plate compactor used for the vibration source this time is different from the vibration source due to actual traffic vibration, because it has a difference such as high frequency and steady vibration.
[0078]
(Embodiment 4)
In the fourth embodiment, the inventors, Motomatsu Matsuoka and Haruyuki Yamamoto, considered the cyclic shear characteristics and damping constant of the damping structure. In other words, a full-scale experiment was conducted on the cyclic shear characteristics of a “soil pile column” in which a damping structure D in which sandbags S are arranged in a column shape (columnar shape) on the building foundation, thereby reinforcing the building foundation ground. .
[0079]
From the results of repeated shear tests of two and six layers of sandbag S, the equivalent damping constant heq (hereinafter referred to as damping constant heq) of the damping structure D is a large value of about 0.3. It was found that the damping structure D was a high damping structure. From this, it turned out that the foundation reinforcement by the damping structure D has the advantage that not only the ground supporting force can be increased, but also the seismic isolation effect can be expected.
[0080]
1. Repeated simple shear test of granular materials
In order to compare the damping constant heq of the damping structure D and the damping constant heq of only the granular material used as the filling material of the sandbag S, first, a repeated simple shear test of the granular material was performed. The simple shear tester used has a mechanism for loading a shearing force via a manual gear. The specimen has a diameter of 7 cm and a height of 2 cm, and is restrained by a rubber sleeve and a Teflon (registered trademark) ring. Samples used were Nikko Silica Sand No. 6 (average particle size of 0.25 mm) and White Silver Silica Sand No. 3 (average particle size of 1.2 mm). The test was conducted with displacement control, and the shear strain γ (%) was gradually increased to 0.2, 0.5, 1, 2, 3, and repeated. The normal stress σ was performed in two types of 130 kPa and 310 kPa. All the gap ratios were 0.94. Examples of test results are shown in FIGS. The figure (A) is a test result of σ = 130 kPa for Nikko Silica Sand No. 6, and the figure (B) is a test result of σ = 130 kPa for White Silver Silica Sand No. 3.
[0081]
2. Cyclic shear test of real damping structure
The real vibration damping structure D was subjected to a cyclic shear test using a large cyclic shear tester. This shear tester has a mechanism capable of loading a vertical load and a horizontal load independently, and a rhombus frame is attached so that the loading plate is not twisted or rotated. The test is performed under strain control, and the shear stress γ (%) is gradually increased to 0.2, 0.5, 1, 2, 3 and repeated in the same manner as the repeated shear test of granular materials, and the normal stress σ is repeated. Was similarly performed at 130 kPa and 310 kPa. Nikko silica sand No. 6 (average particle size of 0.25 mm) and white silver silica sand No. 3 (average particle size of 1.2 mm) were used as the granular materials. The number of laminated layers was 2 layers and 6 layers. 24 (A) and 24 (B) show the test results of damping structure D obtained by vertically stacking sandbag S containing Nikko Silica Sand No. 6 in 6 layers. 25A and 25B show the test results of the damping structure D stacked vertically. In these figures, FIG. (A) shows the test results for σ = 130 kPa, and FIG. (B) shows the test results for σ = 310 kPa. Moreover, about the damping structure D which piled up the sandbag containing white silver quartz sand No. 3 by the lamination | stacking number two layers, the test result performed at (sigma) = 130kPa is shown in FIG.
[0082]
3. Comparison of damping constant between damping structure and granular material
The damping constant heq was calculated from the above repeated shear test results and compared. The attenuation constant heq is defined as follows.
[0083]
[Expression 1]
heq = ΔW / (2πW)
[0084]
Here, since ΔW is the loss energy of one cycle and W is the elastic strain energy, the damping constant heq means the ratio of the loss energy to the elastic strain energy. That is, the larger the loop area, the larger the damping constant heq. 27 and 28 show the attenuation constant heq calculated by the equation 1 for each shear strain γ. FIG. 27 shows the result in the case of Nikko silica sand No. 6, and FIG. 28 shows the result in the case of white silver silica sand No. 3.
[0085]
27 and 28, it can be seen that the damping constant heq of the damping structure D is substantially the same as or slightly larger than the granular material that is the filling material of the clay in the range where the shear strain γ is 1% or more. Further, even when the shear strain γ is in the range of 1% or less, the damping constant heq is not reduced as in the case of the granular material, and a large damping performance is maintained. In general, soil has a large damping constant heq in the range where the shear strain γ is large, but it is said that if the building foundation is reinforced with concrete or the like, the rigidity increases, the shear strain γ decreases, and the damping constant heq decreases. . However, it was found that the damping structure D maintains high damping performance even in a small strain range. This is inferred from a shear force-displacement relationship in which a large shear force is exhibited from zero displacement in a friction test between the sandbags, and then slip between the sandbags occurs.
[0086]
In addition, it can be seen from FIG. 28 that the damping constant heq is almost the same when the number of sandbags is two and six. This indicates that all forms of masonry foundations have high damping performance, which means that the design of the superstructure is much easier when the building is designed using the masonry foundation. Moreover, the value of damping constant heq = 0.3 is an order of magnitude larger than the damping constant heq = 0.05 of the concrete structure used in the design and the damping constant heq = 0.02 of the steel structure. You can see the high attenuation performance.
[0087]
As described above, the vibration damping structures of Embodiments 1 to 4 exhibit high vibration damping properties. And this vibration damping structure can satisfy the demands such as suppression of environmental vibrations due to tracks, roads, construction sites, etc. and earthquake countermeasures for buildings.
[Brief description of the drawings]
FIG. 1 is a side view of a vibration damping structure according to Test 1 of Embodiment 1. FIG.
2 is a side view of a partial cross section of another structure according to Test 1 of Embodiment 1. FIG.
3 is a side view of a partial cross section of another structure according to Test 1 of Embodiment 1. FIG.
4 is a side view of a vibration damping structure according to Test 2 of Embodiment 1. FIG.
5 is a side view of another vibration damping structure according to Test 2 of Embodiment 1. FIG.
6 is a side view of another vibration damping structure according to Test 2 of Embodiment 1. FIG.
7 is a side view of another vibration damping structure according to Test 2 of Embodiment 1. FIG.
8 is a side view of a vibration damping structure according to Test 3 of Embodiment 1. FIG.
9A and 9B relate to the vibration damping structure of the second embodiment, and FIG. 9A is a side view and FIG. 9B is a plan view.
10 is a graph showing measurement results of the vibration damping structure shown in FIG.
11A and 11B relate to another vibration damping structure of the second embodiment, and FIG. 11A is a side view of a partial cross section, and FIG.
12A and 12B relate to another vibration damping structure of the second embodiment, and FIG. 12A is a partial cross-sectional side view, and FIG.
13 is a graph showing measurement results of the vibration damping structure shown in FIG.
14 is a graph showing measurement results of the vibration damping structure shown in FIG.
FIGS. 15A and 15B relate to the vibration damping structure of the third embodiment, in which FIG. A is a side view of a partial cross section, and FIG.
16 is a graph showing measurement results of the vibration damping structure shown in FIG.
FIGS. 17A and 17B relate to another vibration damping structure of Embodiment 3, in which FIG. A is a side view of a partial cross section, and FIG.
18 is a graph showing a measurement result when an electric plate compactor is used in the vibration damping structure shown in FIG.
FIG. 19 is a graph showing measurement results when an engine type plate compactor is used in the vibration damping structure of FIG. 17;
20A is a side view of a partial cross section, and FIG. 20B is a plan view of another vibration damping structure of Embodiment 3. FIG.
FIG. 21 is a graph showing measurement results of the first and second vibration damping structures in the vibration damping structure of FIG. 20;
22 is a graph showing a measurement result of the second vibration damping structure in the vibration damping structure of FIG. 20;
FIG. 23 is a graph showing a test result of σ = 130 kPa for Nikko Silica Sand No. 6 according to Embodiment 4, and FIG. 23 (B) is a test result of σ = 130 kPa for Silver White Silica Sand No. 3; It is a graph which shows.
FIG. 24 relates to a vibration damping structure obtained by vertically stacking sandbags containing Nikko Silica Sand No. 6 in Embodiment 4, with FIG. (A) being a graph showing test results for σ = 130 kPa. B) is a graph showing the test result of σ = 310 kPa.
FIG. 25 relates to a vibration damping structure in which sandbags containing white silver silica sand No. 3 in Embodiment 4 are vertically stacked with a stacking number of 6 layers. FIG. (A) is a graph showing test results of σ = 130 kPa. B) is a graph showing the test result of σ = 310 kPa.
FIG. 26 is a graph showing a test result of σ = 130 kPa in relation to a damping structure in which sandbags containing white silver silica sand No. 3 in Embodiment 4 are vertically stacked with two layers.
FIG. 27 is a graph showing the relationship between the shear strain of Nikko Silica Sand No. 6 and the equivalent attenuation constant according to the fourth embodiment.
FIG. 28 is a graph showing the relationship between the shear strain of white silver silica sand No. 3 and the equivalent attenuation constant according to the fourth embodiment.
[Explanation of symbols]
1-5, 11-14, 21-24, 31-36, S ...
D, D1 to D10 ... damping structure (d61, d81, d91, d101 ... first damping structure, d62, d82, d92, d102 ... second damping structure)
B ... Ground
V, V1, V2 ... Oscillation sources

Claims (6)

The damping structure in the ground provided by providing the oscillation source emitting vibrations on該制vibration structure, the vibration of emitting excitation source attenuated by該制vibration structure, to the outside of the該制vibration structure A vibration control method for limiting the propagation of vibrations of
The vibration damping structure is formed by laminating at least two layers in the vertical direction with a plurality of sandbags being independent from each other. Each sandbag is filled with a granular material and the granular material. It is a flat body made of a bag made of a material that can be bent by its own weight or an external force and is difficult to stretch. Damping method characterized by being laminated in such a manner. The structure vibration control in the ground provided by providing a static mounting body wishing to limit the vibration on該制vibration structure, when there is an oscillation source emitting vibrations outside the該制vibration structure, the vibration A damping method for limiting the propagation of vibrations to the stationary body on the damping structure,
The vibration damping structure is formed by laminating at least two layers in the vertical direction with a plurality of sandbags being independent from each other. Each sandbag is filled with a granular material and the granular material. It is a flat body made of a bag made of a material that can be bent by its own weight or an external force and is difficult to stretch. Damping method characterized by being laminated in such a manner. The structure vibration control in the ground provided by separating the該制vibration structure and a static mounting body wishing to limit the oscillation source and this vibration to emit vibrations, emits vibrations outside the該制vibration structure oscillation When there is a source, the vibration damping structure attenuates the vibration as a barrier, and restricts the propagation of vibration to the other external stationary body,
The vibration damping structure is formed by laminating at least two layers in the vertical direction with a plurality of sandbags being independent from each other. Each sandbag is filled with a granular material and the granular material. It is a flat body made of a bag made of a material that can be bent by its own weight or an external force and is difficult to stretch. Damping method characterized by being laminated in such a manner. The vibration damping method according to any one of claims 1 to 3, wherein the damping structure is formed by horizontally arranging a plurality of sandbags. 5. The vibration damping method according to claim 4 , wherein the damping structure is placed so as to straddle the upper sandbag over a plurality of lower sandbags. 5. The vibration damping method according to claim 4, wherein the damping structure is placed so that the upper sandbag does not straddle the plurality of lower sandbags.

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