JP2020190096A - Vibration reduction structure, vibration reduction method, and sealing body - Google Patents

Abstract

To provide a vibration reduction structure capable of being easily constructed in an object ground and being removed after usage.SOLUTION: A vibration reduction structure 1 comprises: a mixed soil layer 2 constituted of a sealing body 21 in which a mixture of polyvinyl alcohol, a cross-linking agent and soil is sealed in an impermeable bag; and a metal plate layer 3 laid on the mixed soil layer 2. The mixture of polyvinyl alcohol, a cross-linking agent and soil is solidified to become a structure having high toughness and easily absorbing vibration, and has high soil bearing capacity. This is sealed in the impermeable bag, thereby being prevented from drying and maintaining the effect.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vibration reduction structure, a vibration reduction method, and an inclusion body.

When heavy machinery runs at a construction site, vibration occurs. It is required to reduce the vibration so that it is not transmitted to neighboring houses and the like. Conventionally, it has been known that a polymer aqueous solution containing polyvinyl alcohol and a cross-linking agent is directly injected into the ground or mixed with earth and sand for the purpose of absorbing vibrations caused by the passage of trains and automobiles ( Patent Document 1). As a result, it is possible to improve the ground with high flexibility and excellent vibration absorption.

JP-A-2002-371278

However, since the above method permanently modifies the ground in consideration of the water impermeability and deformation strain of the target ground, it cannot be said that it is suitable for vibration reduction applications at temporary construction sites. .. An object of the present invention is to provide a vibration reduction structure that can be easily constructed on a target ground and that can be easily removed after use, and a vibration reduction method using the same. Another object of the present invention is to provide an inclusion body suitable for constructing the vibration reduction structure.

The present invention comprises a mixed soil layer composed of an enclosure in which a mixture of polyvinyl alcohol, a cross-linking agent, and soil is sealed in an impermeable bag, and a metal plate layer laid on the mixed soil layer. Provided is a vibration reduction structure comprising.

Further, in the present invention, a mixed soil layer composed of an enclosure in which a mixture of polyvinyl alcohol, a cross-linking agent, and soil is sealed in an impermeable bag is provided on the target ground, and a metal is placed on the mixed soil layer. Provided is a vibration reduction method for laying a plate layer. As an example of this construction, a method may be adopted in which a bag before encapsulating the mixture is laid on the target ground, and then the mixture is enclosed in the bag to provide a mixed soil layer.

In the present invention, the mixture of polyvinyl alcohol, cross-linking agent and soil becomes a structure having high toughness and easily absorbing vibration when solidified, and has high ground resistance. By enclosing this in an impermeable bag, drying is prevented and the effect is maintained. The present invention is suitable for heavy machinery to travel by laying a metal plate layer on a mixed soil layer composed of an inclusion body in which this structure is enclosed. Further, since the inclusion body has a bag structure and polyvinyl alcohol or the like is not mixed with the target ground, it can be easily removed after the heavy machinery no longer needs to travel. Therefore, the vibration reduction structure of the present invention can be easily constructed on the target ground and can be easily removed after use.

In the present invention, the mixing ratio of polyvinyl alcohol, the cross-linking agent and soil is preferably 1: 5 to 1:40 on a weight basis.

The present invention also provides an inclusion body in which a mixture of polyvinyl alcohol, a cross-linking agent, and soil is encapsulated in an impermeable bag. This inclusion body is suitable for forming the vibration reduction structure.

According to the present invention, it is possible to provide a vibration reduction structure that can be easily constructed on the target ground and that can be easily removed after use, and a vibration reduction method using the same. Further, according to the present invention, it is possible to provide an inclusion body suitable for constructing the vibration reduction structure.

It is a side sectional view when the vibration reduction structure of this embodiment is applied to the target ground. (A) is a perspective view showing a state in which inclusion bodies are spread to form a mixed soil layer. (B) is a perspective view of the vibration reduction structure of this embodiment. It is a perspective view of a bag. It is a figure which shows the result of the uniaxial compression test. It is a figure which shows the result of the running test. It is a figure which shows the result of the running test.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same parts or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.

(Vibration reduction structure)
The vibration reduction structure of the present embodiment reduces vibration so that vibration generated when a heavy machine travels at a construction site is not easily transmitted to a neighboring area. Here, "heavy machinery" refers to large special vehicles such as cranes, backhoes, and vibrating rollers. Further, "reducing vibration" means constructing a structure that absorbs vibration at the source of vibration and suppressing vibration propagating in the ground to a small value.

As shown in FIGS. 1 and 2, the vibration reduction structure 1 of the present embodiment includes a mixed soil layer 2 and a metal plate layer 3 laid on the mixed soil layer 2. The vibration reduction structure 1 is provided on the target ground 4 on which heavy machinery is scheduled to travel. At this time, the vibration reduction structure 1 may be provided directly on the target ground 4, and as shown in FIG. 1, the gravel layer 5 is laid on the target ground 4 and then the vibration is reduced on the gravel layer 5. The structure 1 may be provided. The type of gravel is not particularly limited, and for example, gravel having a particle size of 1 mm to 40 mm can be used.

The mixed soil layer 2 is composed of a plurality of inclusion bodies 21 spread in the horizontal direction. Typically, as shown in FIG. 2A, the mixed soil layer 2 is formed by laying a plurality of inclusion bodies 21 so as to spread in two directions, the traveling direction of the heavy machine and the vehicle width direction. ing. The thickness of the mixed soil layer 2 is preferably 5 cm or more, and more preferably 15 cm or more.

The metal plate layer 3 is made of a metal plate, and here is a sheet metal plate 31. The floor iron plate 31 is made of iron and has a thickness of 10 cm to 25 cm. As shown in FIG. 2B, a plurality of iron plates 31 are laid so as to cover the upper surface of the mixed soil layer 2. The heavy machine runs on the metal plate layer 3.

The inclusion body 21 is formed by enclosing a mixture of polyvinyl alcohol, a cross-linking agent, and soil in an impermeable bag 6 (FIG. 3). The bag 6 is impermeable and is made of, for example, a resin. The bag 6 preferably has a high light-shielding property. It is preferable that the bag 6 has a substantially rectangular parallelepiped shape as a storage portion of the mixture, as shown in FIG. 3, for the convenience of laying it down and for the convenience of easily maintaining the horizontality of the upper surface. The bag 6 shown in FIG. 3 is substantially rectangular in plan view, and the height in side view is preferably 5 cm or more when the mixture is enclosed.

The mouth portion 61 of the bag 6 is preferably provided on the surface that becomes the upper surface when the bag 6 is spread, for the convenience of pouring the mixture into the bag 6 and for the convenience of spreading the bag 6. The mouth portion 61 preferably has a tubular shape having a predetermined length from the viewpoint of facilitating closing.

The mouth 61 of the bag 6 is preferably closed after the mixture has been poured. As a method of closing the mouth portion 61, various modes such as tying, tying with a string, and fastening with a tape can be adopted. In FIG. 2A, the mouth portion 61 is taped. If the mixture is solidified after being poured in, there is no possibility that the contents will flow out from the bag 6, so it is not always necessary to close the mouth portion 61.

Further, the bag 6 may be provided with a handle in order to make it easier to lift the inclusion body 21 when the vibration reduction structure 1 is removed. For example, in consideration of lifting with a crane, an annular handle may be attached to the side surface of the bag 6 so that the bag can be lifted directly with a hook of the crane.

The mixture enclosed in the bag 6 is a mixture in which polyvinyl alcohol, a cross-linking agent, and soil are uniformly mixed and then solidified (hereinafter, this is referred to as a "solidified body"). The type of soil is not limited, and for example, soil generated at a construction site can be used. Solid material, uniaxial compression test: preferably compressive stress σ to withstand in (JIS A 1216 was measured conforming to 2009) is 150 kN / ^{m 2} or more, more preferably 180kN / ^{m 2} or more, 200 kN further preferably / ^{m 2} or more, particularly preferably 220KN / ^{m 2} or more. Further, in the same test, the compressive strain ε preferably withstands 5%, more preferably withstands 10%, further preferably withstands 15%, and particularly preferably withstands 18%.

The solidified body has a high toughness and an elastic rubber-like shape. Therefore, it is possible to absorb the vibration directly received from the vibration source.

In the above mixture, the mixing ratio of polyvinyl alcohol, the cross-linking agent, and soil is preferably 1: 5 to 1:40, more preferably 1: 10 to 1:35, and 1:15 on a weight basis. It is more preferably ~ 1:30, and particularly preferably 1:22 to 1:25.

As for the mixing ratio of polyvinyl alcohol and the cross-linking agent, the ratio of the active ingredient between the polyvinyl alcohol unit in the polyvinyl alcohol and the reaction site in the cross-linking agent is preferably 1: 0.1 to 1:20 on a weight basis. It is more preferably 1: 1 to 1:10, and even more preferably 1: 3 to 1: 5. By adjusting the mixing ratio of polyvinyl alcohol and the cross-linking agent, the natural frequency of the solidified product can be adjusted.

The cross-linking agent is preferably a compound having two or more reaction points in the molecule that react with polyvinyl alcohol. Among them, a compound having two or more methylol groups in the molecule is preferable, and methylolmelamine is preferable. Either dimethylol melamine or trimethylol melamine may be used.

Other components may be added as components of the mixture. For example, an acid such as lactic acid may be added as a pH adjuster. By setting the pH to 5 or less, the reaction between polyvinyl alcohol and the cross-linking agent is promoted, and gelation is facilitated.

(How to build a vibration reduction structure)
The vibration reduction structure 1 can be constructed as follows. First, gravel is laid on the target ground 4 as needed to form a gravel layer 5. The mixed soil layer 2 is formed on the target ground 4 or the gravel layer 5. The method for forming the mixed soil layer 2 is as follows.

First, polyvinyl alcohol and a cross-linking agent are mixed and stirred until gelation begins. The polyvinyl alcohol and the cross-linking agent may be mixed after being made into an aqueous solution in advance. Upon mixing, a pH regulator may be added to acidify the pH. For example, it is preferable to add an appropriate amount of lactic acid to adjust the pH to about 4. When gelation begins, mix the soil with it and stir. While the mixture is fluid, the mixture is placed in bag 6. At this time, an empty bag 6 may be spread on the target ground 4 or the gravel layer 5 and then the mixture may be sealed in the bag 6, or the mixture 21 may be sealed in the bag 6 at another place. It may be carried and spread on the target ground 4 or the gravel layer 5. Here, "gelling" refers to a process in which a substance having high fluidity loses fluidity and finally solidifies.

The mixture inside the inclusion body 21 is fluid at the beginning of gelation at the beginning of inclusion, but solidifies after a curing period to become a solidified body. After the mixture is completely solidified, or when solidification is in progress, the vibration-reducing structure 1 is completed by laying the iron plate 31 on the mixed soil layer 2 to form the metal plate layer 3. The mixture may be solidified by the time the heavy equipment runs. The removal of the vibration reduction structure 1 is achieved by removing the floor iron plate 31 and the inclusion body 21 in order.

(effect)
In the vibration reducing structure 1 and the vibration reducing method described above, when the mixture of polyvinyl alcohol, the cross-linking agent and the soil is solidified, the structure has high toughness but elasticity. This structure easily absorbs vibration and has high bearing capacity. Therefore, the vibration generated by the traveling of the heavy machine can be reduced, and the vibration propagated to the surrounding environment can be reduced. Further, since the vibration reduction structure 1 and the vibration reduction method of the present embodiment do not directly solidify the target ground 4, the target ground 4 is not permanently modified and is excellent in environmental conservation. .. The inclusion body 21 and the iron plate 31 are relatively easy to lay and remove. That is, the vibration reduction structure 1 and the vibration reduction method of the present embodiment can be easily constructed on the target ground 4 and can be easily removed after use.

Further, since the mixture and the solidified body obtained by solidifying the mixture are sealed in an impermeable bag, drying is prevented and the vibration reducing effect is maintained.

Further, although the solidified body has an effect of reducing vibration, the vibration is amplified and tends to be large in the vicinity of the natural frequency of the solidified body. However, since the natural frequency of the solidified body can be adjusted by adjusting the mixing ratio of polyvinyl alcohol and the cross-linking agent as described above, the frequency of vibration to be reduced and the natural frequency of the solidified body do not overlap. , The mixing ratio of polyvinyl alcohol and the cross-linking agent can be adjusted.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

Hereinafter, the contents of the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

(Comparative Example 1)
A running path having a width of 3.5 m and a length of 10 m was constructed according to the following procedure. A gravel layer was formed by laying gravel on the target ground so as to have a height of 20 cm. An iron plate with a width of 350 cm x 1000 cm and a thickness of 10 cm was laid on the site of a width of 3 m and a length of 10 m on the gravel layer.

A crane (ground pressure 47 kPa), a backhoe (ground pressure 36 kPa), and a vibrating roller ran on the iron plate. The vibration was measured at a position 2.5 m away from the center position in the width direction of the traveling vehicle (corresponding to the area where gravel is not laid). The frequency to be measured was 1 Hz to 100 Hz, and the vibration level (dB) was measured.

(Comparative Example 2)
A running path having a width of 3.5 m and a length of 10 m was constructed according to the following procedure. A gravel layer was formed by laying gravel on the target ground so as to have a height of 20 cm. Urethane foam elastomer was spread on the site of 3.5 m in width and 10 m in length on the gravel layer, and an iron plate was further laid on it.

Similar to Comparative Example 1, the crane, backhoe, and vibrating roller ran on the iron plate, and the vibration level was measured for each.

(Example 1)
A running path having a width of 3.5 m and a length of 10 m was constructed according to the following procedure. A gravel layer was formed by laying gravel on the target ground so as to have a height of 20 cm. An impermeable polyethylene bag (bag having the shape shown in FIG. 3) having a bottom surface of 250 cm × 50 cm and a height of 10 cm was spread tightly on the site of 3.5 m in width × 10 m in length on the gravel layer. ..

According to the formulation shown in Table 1, an aqueous solution obtained by further diluting a 10% aqueous solution of polyvinyl alcohol (PVA), an aqueous solution of dimethylol melamine as a cross-linking agent, a drug, and lactic acid as a pH adjuster are mixed and stirred to obtain pH. Was set to 4. After 3 hours, it was confirmed that these gelation had started, and mountain sand as soil was mixed and stirred. The mixture was then poured into each polyethylene bag and the mouth of the bag was taped. The mixture was cured for 1 day and solidified. After that, an iron plate was laid on it.

In addition, a specimen for performing a uniaxial compression test in accordance with JIS A 1216: 2009 was prepared with the same composition, and the uniaxial compression test was performed.

Similar to Comparative Example 1, the crane, backhoe, and vibrating roller ran on the iron plate, and the vibration level was measured for each. After that, the same running test was conducted after exposing the constructed vibration-reducing structure to the environment for one month.

The result of the uniaxial compression test is shown in FIG. From this result, it can be seen that the solidified body in Example 1 does not break even if the compressive strain is 18%, and can withstand a compressive stress of 200 kN / m ² or more.

For Comparative Examples 1 and 2 and Example 1, the vibration levels at each frequency are shown in FIG. In addition, for Example 1, the vibration level measured one month later is also shown in FIG. In each figure, "no countermeasure" indicates Comparative Example 1, "foamed resin" indicates Comparative Example 2, and "PVA mixed soil" indicates Example 1. From these results, it can be seen that the vibration level can be reduced by the configuration of Example 1, and that the effect is maintained to some extent even after one month of environmental exposure.

The present invention can be used to reduce vibration generated by running a heavy machine.

1 ... Vibration reduction structure, 2 ... Mixed soil layer, 3 ... Metal plate layer, 4 ... Target ground, 5 ... Gravel layer, 6 ... Bag, 21 ... Inclusion body, 31 ... Sheet metal plate, 61 ... Mouth.

Claims (6)

A mixed soil layer composed of an inclusion body in which a mixture of polyvinyl alcohol, a cross-linking agent, and soil is sealed in an impermeable bag.
A vibration-reducing structure comprising a metal plate layer laid on the mixed soil layer. The vibration-reducing structure according to claim 1, wherein the mixing ratio of the polyvinyl alcohol, the cross-linking agent, and the soil is 1: 5 to 1:40 on a weight basis. A mixed soil layer composed of an inclusion body in which a mixture of polyvinyl alcohol, a cross-linking agent, and soil is sealed in an impermeable bag is provided on the target ground.
A vibration reduction method in which a metal plate layer is laid on the mixed soil layer. The vibration reduction method according to claim 3, wherein the bag before encapsulating the mixture is laid on the target ground, and then the mixture is enclosed in the bag to provide the mixed soil layer. The vibration reduction method according to claim 3 or 4, wherein the mixing ratio of the polyvinyl alcohol, the cross-linking agent, and the soil is 1: 5 to 1:40 on a weight basis. An inclusion body in which a mixture of polyvinyl alcohol, a cross-linking agent, and soil is sealed in an impermeable bag.

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