JP2018100588A - Base isolation member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base isolation member using an inorganic granular material which is an inorganic granular material for forming a base isolation material having an excellent base isolation effect, and is remarkably excellent in economical efficiency than a conventional one.SOLUTION: A base isolation member is a base isolation member filling a bag body or a cylindrical body having flexibility, where the bag body or cylindrical body constitutes a planer reinforcement material, and the base isolation material is formed of an inorganic granular material which contains 70% or more of inorganic particles having a particle size of 75 μm or less, has a void ratio of 0.3 or more and 0.6 or less, and contains 0.08% or more and 10% or less of an admixture.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a vibration isolating member using an inorganic granular material. More specifically, a novel inorganic granule that has excellent physical properties as a vibration-isolating material while being a material capable of producing only an inorganic granule material excellent in material supply stability and economy and moisture as main components. The present invention relates to a vibration isolation member using a material.

  As a means for attenuating the vibration energy at the time of earthquake and improving the seismic isolation of the structure, for example, in a huge building such as a high-rise building, the upper structure and the lower structure on the foundation side A seismic isolation method in which various seismic isolation devices such as a seismic isolation damper are installed in between (see Patent Documents 1 and 2).

  On the other hand, as another approach to improve the seismic isolation of the structure, various seismic isolation materials were also proposed that are intended to provide the target ground with seismic isolation by filling the ground where the structure is installed. (Patent Document 3). As such a filling type seismic isolation material, in recent years, a seismic isolation material in which a plastic microballoon excellent in impact resistance and shape restoration property is blended in a silicone-based seismic isolation material has been developed (Patent Document 4). reference).

  On the other hand, as a general construction method of a so-called anchor structure in which an anchor metal is fixed to a structure made of concrete or the like, an anchor insertion hole is formed on the surface of the concrete structure or the like, and the anchor insertion hole is anchored to the anchor insertion hole. A method of filling the space between the anchor hardware and the inner peripheral surface of the insertion hole with a filling material after inserting the metal fitting is performed (see Patent Document 5). A reactive liquid resin material or a cement-based material (the main material is cement and the hardener is water or water glass) that can exhibit the tensile resistance of (see Patent Document 6).

Japanese Patent Laid-Open No. 11-2223045 JP 2002-227898 A JP-A-9-105440 Japanese Patent Laid-Open No. 2002-21106 JP 2001-31224 A JP 2011-42963 A

  Here, the seismic isolation devices described in Patent Documents 1 and 2 have a huge cost for manufacturing, installation, and subsequent maintenance. Therefore, in cases other than the application to buildings with particularly high cost-effectiveness such as high-rise buildings, the adoption is often difficult for economic reasons.

  Moreover, about the seismic isolation material of patent documents 3 and 4, the seismic isolation means which fills these in the ground etc. is generally more economical than installation of said seismic isolation apparatus. However, each of these seismic isolation materials is obtained by adding some dispersion material having impact resistance, shape restoration property, etc. in addition to the main resin such as silicone. All of these seismic isolation materials require the addition of the above-mentioned dispersing agent in order to develop a seismic isolation effect, and are highly dependent on specific materials such as the above-described plastic microballoons. The above-mentioned specific materials are not always guaranteed to be cheap and stable in large quantities. Therefore, seismic isolation materials that are more economical are in demand.

  In addition, as for the filling material used for forming the anchor structure described in Patent Document 6, there is a demand for the development of a material that further increases the economic efficiency while maintaining the necessary tensile resistance after solidification. It was.

  The present invention provides a vibration isolating member using an inorganic granular material that can be used as a vibration isolating material having an excellent seismic isolation effect, which is far more economical than conventional products. This is the issue.

  As a result of intensive studies, the present inventors, for example, use general-purpose and easily available inorganic particles represented by limestone powder as the main material, and other components include only moisture and a small amount of an admixture. Although it is composed of inorganic granular materials, it is totally unpredictable from the conventional methods for these inorganic granular materials by limiting the particle size and gap ratio of the main inorganic particles to a specific range. As a result, the present inventors have found that an extremely excellent effect can be expressed, and have completed the present invention. More specifically, the present invention provides the following.

  (1) The vibration isolation material is a vibration isolation member filled in a flexible bag or cylinder, and the bag or cylinder constitutes a planar reinforcing material, and The vibration-isolating material contains 70% or more of inorganic particles having a particle size of 75 μm or less, the gap ratio is 0.3 or more and 0.6 or less, and the admixture is 0.08% or more and 10% or less. A vibration isolation member made of material.

  According to the invention of (1), the composition is composed mainly of inorganic particles and water, and a small amount of admixture is added as the other components. A vibration-isolating material that can be used as a material and a filling material for anchor structure can be obtained.

  And it is composed of inorganic particulate material and water as the main components, and the other components are composed of only a small amount of admixture. It is possible to provide a completely new vibration isolating material that exhibits the above seismic isolation effect. In addition, this vibration isolation material has not only vibrations such as earthquakes but also vibration reduction effects for high frequencies such as traffic vibrations.

  According to the invention of (1), in the surface layer processing method described in Japanese Patent No. 3729169, the vibration isolating material is used as a filling material to be filled in the flexible hose portion in the rigid reinforcing body used for the surface layer processing of the soft ground. The seismic isolation, long-term durability and economic efficiency of such a seismic isolation member can be significantly improved.

  (2) The vibration isolation member according to (1), wherein the inorganic particles are limestone powder.

  According to the invention of (2), the vibration-isolating material of (1) can be produced by limestone powder, which is a very versatile, widely distributed, inexpensive and highly stable material. Therefore, the economic efficiency and ease of implementation of the invention of (1) can be further enhanced.

  (3) A surface treatment method for soft ground, in which the vibration-isolating member according to (1) or (2) is laid on the ground.

  According to the invention of (3), application of the vibration-isolating material of the present invention to the “surface treatment method for soft ground” disclosed in Japanese Patent No. 3729169 is conceivable. In this processing method, instead of the conventional mortar as a filling material to be filled in the flexible hose, the planar reinforcing material is given rigidity by filling the vibration isolating material of the present invention as the filling material. At the same time, it is possible to impart earthquake resistance during an earthquake.

  According to the present invention, a vibration isolating material having an excellent seismic isolation effect, and an insulating material made of an inorganic granular material that can also be used as an anchor structure filling material having an excellent tensile resistance, It is possible to provide a vibration isolating member using a vibration isolating material that is far more economical than conventional products.

It is a graph which shows the relationship between the gap ratio of the inorganic granular material of this invention, and a water content ratio. It is a graph which shows the result of the triaxial compression test about the vibration isolation material which consists of an inorganic granular material of this invention. It is a graph which shows the result of the confirmation test of the vibration isolation effect and vibration reduction effect about the vibration isolation material which consists of an inorganic granular material of this invention. It is a graph which shows the result of the test which confirms the influence of aged deterioration about the vibration isolation material which consists of an inorganic granular material of this invention. It is a graph which shows the test result which concerns on the tensile resistance about the filling material for anchor structures which consists of an inorganic granular material of this invention. It is a schematic diagram with which it uses for description of the example of application to the underground structure which is preferable one Embodiment of the vibration isolation material which consists of an inorganic granular material of this invention. It is a schematic diagram with which it uses for description of the other application example to the underground structure which is preferable one Embodiment of the vibration isolating material consisting of the inorganic granular material of this invention. It is a schematic diagram with which it uses for description of the example of application to the road pavement which is one preferable embodiment of the vibration isolator which consists of an inorganic granular material of this invention. It is a schematic diagram with which it uses for description of the example used as a filling material to the vibration isolation structure which is preferable one Embodiment of the vibration isolation material consisting of the inorganic granular material of this invention. It is a schematic diagram with which it uses for description of the anchor structure which is preferable one Embodiment of the filling material for anchor structures which consists of an inorganic granular material of this invention.

  The inorganic granular material of the present invention is an inorganic granular material mainly composed of inorganic particles having a specific granularity. And the inorganic granular material of this invention expresses the outstanding physical property in at least two uses which was unpredictable from the technical knowledge of this field conventionally. One of the two applications is an application as a seismic isolation material, and the other is an application as a filling material for anchor structures. Hereinafter, an outline of the inorganic particulate material of the present invention, a preferred embodiment when used as a “seismic isolation material”, and a preferred embodiment when used as a “filling material for anchor structure” will be sequentially described.

<Inorganic granular material>
The inorganic granule material of the present invention has the minimum three essential components of the admixture as an inorganic granule and water as main materials and other additive materials. Like conventional seismic isolation materials described in Patent Documents 3 and 4, in addition to the above three components, which are constituent elements of the present invention, in conventional seismic isolation materials, special rubbers and plastics for further expressing seismic isolation The specific raw material is an essential component. On the other hand, the inorganic granular material of the present invention is characterized in that, as described above, the component composition of the material is a simple composition made of only extremely inexpensive materials.

As the inorganic particles constituting the inorganic particulate material, various inorganic particles that are non-hydraulic substances can be used. For example, limestone powder (calcium carbonate), silt, clay, crushed stone, blast furnace slag, coal ash and the like can be used. Among them, in the civil engineering material field, it is possible to preferably use limestone powder, which is a material that is extremely versatile and is widely distributed at low cost and has high supply stability. Limestone powder includes one or both of powders obtained by pulverizing limestone (a mineral mainly composed of CaCO ₃ ) (derived from crushed stone defined for concrete and limestone powder prepared as an industrial product) Can be preferably used.

  About the particle size and particle size distribution of the inorganic particles constituting the inorganic particle material, for example, the particle size is extremely small compared to general cementitious materials (mortar and concrete), and the particle size dispersion is also small. It is preferable. Specifically, the inorganic particles used in the present invention comprise 70% or more, preferably 75% or more of particles having a particle size of 75 μm or less.

  As the admixture, various materials used for general concrete production can be used as long as the fluidity of the kneaded material is not impaired. Specific examples include water reducing agents, AE water reducing agents, high performance water reducing agents, high performance AE water reducing agents, retarders, dispersants, thickeners, and the like. These admixtures can be added in a range where the mass ratio in the kneaded product is 10% or less, but even when the addition amount is 1% or less (for example, 0.1% or more and 1% or less) Results.

  The inorganic particle material of the present invention is obtained by adding water to the above-mentioned inorganic particles and admixture, and is characterized by an extremely small gap ratio. Specifically, the gap ratio of the inorganic granular material of the present invention is 0.3 or more and 0.6 or less, preferably 0.40 or more and 0.55 or less. From the particle shape and particle size of the inorganic particles used in the inorganic particle material of the present invention, the physical lower limit of the gap ratio is about 0.3. Further, when the gap ratio exceeds 0.6, that is, the amount of water increases and the state becomes close to muddy water, and the thixotropy, which is a precondition for exhibiting the effect unique to the present invention, is lost. In addition, all the values of the above-mentioned gap ratio of the inorganic granular material of the present invention are numerical values that can be realized without requiring special additional processing such as compaction.

  The inorganic granular material having such a small gap ratio uses inorganic particles such as limestone powder having a specific particle size distribution as described above, and adjusts the mixing ratio of the admixture and moisture to a specific range. Can be generated. Here, FIG. 1 is a graph showing the correlation between the water content ratio and the gap ratio of the inorganic particulate material of the present invention when limestone powder is used as the inorganic particulate material. As can be seen from this graph, when limestone powder is used as the inorganic particles, the water content ratio is set in a range of approximately 6% to 22%, so that the gap ratio is set to the above low gap ratio, that is, 0.3%. It can be adjusted to a range of 0.6 or less. In addition, about the moisture content cost of the inorganic granular material in this specification, it shall say the moisture content measured by "the soil moisture content test method" of JIS Z 1203: 1999. In addition, the gap ratio of the inorganic particle material in the present specification refers to the volume ratio of the volume of the compounding component other than the inorganic particles (approximately only moisture) in the inorganic particle material to the volume of the inorganic particles. say. Specifically, “gap ratio (e) ≈volume of water / volume of inorganic particulate material (V / V)”. In carrying out the present invention, if the water content ratio, the water density, and the density of the inorganic particles are known, the gap ratio should be approximately grasped from each of these values with sufficient practical accuracy and appropriately implemented. Is possible.

<Vibration isolation material>
The inorganic granular material of the present invention can be preferably used as a seismic isolation material. The name “isolation material” of the present invention attenuates vibration energy not only for “seismic isolation effect” against vibrations such as earthquakes, but also for all vibrations including fine vibrations with high frequency such as traffic vibrations. Therefore, it is not a “general isolation material” that is a conventional general name for this type of material, but a “isolation material”.

  The vibration isolation material made of the inorganic granular material of the present invention (hereinafter also simply referred to as “vibration isolation material”) has thixotropic properties because it is a granular material having a very small gap ratio in the above range. . The vibration-isolating material of the present invention having thixotropy decreases in rigidity when vibration is applied, and the rigidity recovers autonomously after the vibration stops. Because of this unique physical property, for example, it exhibits excellent seismic isolation performance in the event of an earthquake. Furthermore, since the rigidity is self-recovering after an earthquake, it is a maintenance-free material that can be used repeatedly without replacement or maintenance. Can be used as

  In addition, since the vibration-isolating material of the present invention is a granular material with a very small gap ratio, the positive dilatancy effect becomes more prominent as the axial strain increases, and a negative pressure is generated inside the granular material. Thereby, the vibration-isolating structure made of the vibration-isolating material of the present invention has durability with respect to an increase in strain that is not broken even in a large strain region.

  According to the present invention, by specifying the particle size and particle size distribution of the inorganic particulate material as the main material and the gap ratio in the above range, a simple composition in which moisture and an admixture are simply added to the main material. However, it is possible to obtain a vibration isolation material having extremely excellent vibration isolation performance. This is a completely new finding that cannot be easily conceived by any person skilled in the art from any known knowledge. The vibration-isolating material of the present invention should be compared with the conventionally known vibration-isolating materials. Is a novel vibration-isolating material that does not exist at all.

  The above-described vibration-isolating material of the present invention is filled in the ground near the structure to be vibration-isolated, for example, to form a vibration-isolating structure made of the vibration-isolating material, so that the structure has vibration-isolating performance. Can be granted.

  6-8 is a figure which shows typically the example of formation of the vibration isolation structure by the vibration isolation material of this invention, respectively. FIG. 6 shows a state in which the vibration isolation material 1A is formed by filling the space immediately below the underground structure 2 arranged and formed below the ground G with the vibration isolation material of the present invention. FIG. 7 shows a state where the vibration isolation structure 1B is formed on the side surface of the underground structure 2 by the same vibration isolation process. Further, FIG. 8 shows a state where the vibration isolating material 1C is formed by filling the vibration isolating material of the present invention directly under the road pavement. In any example, the vibration isolation structure (1A, 1B, 1C) made of the vibration isolation material of the present invention sufficiently exhibits the effect of attenuating the vibration energy against any vibration such as earthquake and traffic vibration. Can do.

  As illustrated in FIGS. 6 to 8, as a method for forming the vibration isolation structure by filling the vibration isolation material of the present invention into the ground, a conventional method as described in Patent Document 3 is used. That is, a method of drilling the ground with a drilling rod or forming a cavity and then filling a vibration isolating material with a fluid discharge rod. When filling the ground with the vibration isolating material by such a construction method, when using the conventional vibration isolating material, the dispersion material such as plastic microballoon blended in the material becomes the ejection mechanism of the fluid ejection rod. In some cases, the discharge efficiency is lowered due to a burden. In order to avoid this problem, there has been a case where a method of filling the main material and the dispersion material with separate rods and stirring while filling is sometimes employed. In any case, a decrease in workability in the isolation work has been a problem. Since the vibration-isolating material of the present invention has a simple composition that does not contain a dispersion material, such a problem of reduced workability cannot occur. Thus, also from the viewpoint of improving workability of the vibration isolation work, the vibration isolation material of the present invention has a much more advantageous effect than the conventional vibration isolation material.

  Since the vibration isolating material of the present invention has special thixotropy and durability against an increase in strain as described above, a flexible bag or cylinder as shown in FIG. It can also be preferably used as a filling material 1D for the vibration isolation member 3 filled in the body. As an example of a preferable application of such a vibration isolation member, application of the vibration isolation material of the present invention to the “surface treatment method for soft ground” disclosed in Japanese Patent No. 3729169 can be considered. In the same processing method, instead of the conventional mortar as a filling material to be filled in the flexible hose, the vibration-proof material of the present invention is filled as the filling material 1D to give rigidity to the planar reinforcing material. At the same time, it is possible to provide earthquake resistance during an earthquake.

<Filling material for anchor structure>
The inorganic particulate material of the present invention can also be preferably used as a filling material for anchor structure. As described above, the anchor structure filling material (hereinafter also referred to simply as “anchor structure filling material”) made of the inorganic granular material of the present invention is close to a thixotropic fluid and has a high viscosity. By forming a locking portion filled with this anchor structure filling material, a tensile resistance against pulling out of a steel bar or the like is exhibited.

  According to the present invention, by specifying the particle size and particle size distribution of the inorganic particles as the main material, and the gap ratio in the above range, the simple material has a simple composition in which moisture and an admixture are added to the main material. Nevertheless, an anchor structure filling material having excellent tensile resistance can be obtained. This is a completely new finding that cannot be easily reached from any known knowledge even by those skilled in the art, and the anchor structure filling material of the present invention is one of the conventionally known anchor structure filling materials. It is a novel anchoring structure filling material that does not have anything comparable. In addition, the “filling material for anchor structure” in this specification refers to all the filling materials used for forming a structural part that requires tensile resistance, such as an anchor fixing part and other supporting and fixing part in the anchor structure. It is a concept that includes.

  The anchor structure filling material according to the present invention described above has an inexpensive and highly stable anchor structure by, for example, filling a gap space around the anchor member in order to lock the anchor member such as an anchor bolt. Can be formed.

  FIG. 10 is a diagram schematically showing an example of forming an anchor structure using the anchor structure filling material of the present invention. By filling the clearance space around the anchor bolt 4 arranged in the insertion hole provided on the surface of the concrete structure 5 with the filling material for anchor structure of the present invention, the anchor locking portion 1E in the anchor structure 10 is formed. Has been. Since the anchor locking portion 1E made of the inorganic granular material of the present invention is a low-cost material and can exhibit a sufficient tensile resistance, its economy can be maintained while maintaining the preferable performance of the anchor structure 10. Can be improved.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to these examples.

First, inorganic granular materials having the blending ratios shown in Table 1 below were prepared using the following materials.
〔material〕
Inorganic particles: Limestone powder (powder obtained by pulverizing limestone (calcium carbonate powder)), containing 70% by mass or more of particles passing through a 75 μm sieve.
Water admixture: High performance water reducing agent

[Applicability test as a vibration isolation material]
About the inorganic granular material of the Example, the suitability as a vibration isolating material was verified.

(Vibration isolation effect and stiffness recovery effect)
In order to verify the vibration isolation effect and rigidity recovery effect of the inorganic granular material of the present invention as a vibration isolation material, repeated triaxial tests were performed. After preparing a specimen of φ50 mm × h100 mm with the inorganic granular material of Example 1, repeated axial displacement (waveform: sine wave) with a frequency of 0.1 Hz was continuously performed until the half amplitude shear strain became about 2%. It was loaded. The shear elastic modulus ratio (Gn / G ₀ ) before loading, immediately after loading, and after 30 minutes from loading, respectively, is calculated as the shear elastic modulus ratio (Gn / G ₀ ) before the earthquake, immediately after the earthquake, and after 30 minutes after the earthquake, respectively. ₀ ). The results were as shown in Table 2 below. In addition, the same test as above was performed for the inorganic particle material of the comparative example, but for the inorganic particle material of the comparative example having no thixotropy, recovery of rigidity as in the example cannot be expected, before the earthquake, immediately after the earthquake And after 30 minutes from the earthquake, as much as the examples of the shear elastic modulus ratio (Gn / G ₀ ) was not observed.

  From Table 2, the vibration-isolating structure using the vibration-isolating material of the present invention can attenuate the vibration by reducing the shear elastic modulus ratio to less than 0.1 when subjected to vibration caused by an earthquake. It can be seen that, after the vibration is stopped, the rigidity is sufficiently recovered spontaneously.

(Durability against strain force)
Next, about the specimen of the vibration-isolation structure of Examples 1-4 and the comparative example, the triaxial compression test was done and durability with respect to the strain increase was investigated from the stress-strain curve. A graph of the test results is shown in FIG.

  From FIG. 2, since the vibration isolation structure using the vibration isolation material of the present invention is close to the critical gap ratio, the positive dilatancy effect is remarkable, and negative distortion is generated inside the vibration isolation structure as the strain increases. Pressure is generated. Therefore, it can be seen that the vibration-isolating structure is not destroyed even in a large strain region and is excellent in durability against strain increase. Although the same test as described above was performed for the inorganic granular material of the comparative example, the excess pore water pressure becomes a negative pressure for the inorganic granular material of the comparative example that does not have thixotropy and does not reach the critical gap ratio. No, the vibration isolation structure was in a state of failure immediately after the test.

(Vibration reduction effect)
About the inorganic granular material of Example 1, the centrifugal model experiment was conducted and the vibration reduction effect was verified. In the centrifugal model experiment, the inorganic granule material of Example 1 was installed in a shear soil tank of 700 mm width x 220 mm depth x 70 mm height and used as a specimen with a vibration isolation structure, and then a seismic wave equivalent to a level 2 earthquake was input. did. The vibration reduction effect was evaluated by measuring the input acceleration from the ground bottom and the response acceleration on the ground surface. A graph of the test results is shown in FIG. FIG. 3A is a graph showing the input acceleration measured on the ground bottom surface, and FIG. 3B is a graph showing the response acceleration on the ground surface. The graph of FIG. 3 is a graph of the experimental results at 7 Hz vibration, but it is confirmed that the same vibration reduction effect can be obtained even if the same test is performed in the frequency range of 2 to 14 Hz. ing.

  From FIG. 3, it can be seen that the vibration isolation structure using the vibration isolation material of the present invention has a high damping effect of the vibration caused by the earthquake. In addition, it can be seen that the present invention can exhibit a wide range of vibration reduction effects not only for low frequency vibration such as earthquakes but also for high frequency vibrations such as traffic vibrations.

(Aging durability)
About the inorganic granular material of Example 1, the triaxial compression test was done and the aging durability was verified. In the triaxial compression test, specimens of φ50 mm × h100 mm were produced using the inorganic granular material of Example 1, and the mechanical properties of each specimen immediately after production and after sealing at 20 ° C. for 6 months were evaluated. Furthermore, the same test was performed as a specimen of a comparative example using Toyoura sand treated as a general sandy soil as an inorganic granule. The above Toyoura _{sand, SiO 2: 92.6%, Al2O} 3: 3.7%, others are made of _{(Fe 2 O 3, CaO,} MgO, organic) from the particle size 75μm or less of the inorganic particle Is an inorganic granular material having a gap ratio of about 0.78. A graph of the test results is shown in FIG.

  From FIG. 4, it can be seen that the vibration isolation structure using the vibration isolation material of the present invention is excellent in ease of maintenance that is not affected by aging deterioration. It can also be seen that the vibration damping effect is higher than that of a structure made of a general inorganic granular material.

[Applicability test as filling material for anchor structure]
About the inorganic granular material of an Example, the suitability as a filler for anchor structures was verified.

(Tensile resistance)
A test was conducted to verify the tensile resistance of the inorganic granular material of the present invention as a filler for anchor structure. The inorganic granular material of Example 1 was filled into a mold having a width of 450 mm, a depth of 300 mm, and a height of 100 mm, and a columnar steel rod having a diameter of 50 mm and a length of 30 mm was inserted into the material immediately after the filling of the material. . A pull-out test was performed 10 minutes after the insertion, and the tensile resistance was measured. A graph of the test results is shown in FIG. The test was repeated twice and indicated as series 1 and 2 on the graph. In addition, regarding other inorganic granular materials, normal inorganic granular materials have no adhesive force and the like and do not exhibit tensile resistance at all unless compaction is used together. did.

  From FIG. 5, it can be seen that the inorganic granular material of the present invention can be preferably used as a filling material for anchor structure.

1A, 1B, 1C Isolation structure 1D Filling material 1E Anchor locking part 2 Underground structure 3 Isolation member 4 Anchor bolt 5 Concrete structure 10 Anchor structure G Ground

Claims (3)

The vibration isolation material is a vibration isolation member that is filled in a flexible bag or cylinder,
The bag or the cylinder constitutes a planar reinforcing material,
The vibration isolation material is
70% or more of inorganic particles having a particle size of 75 μm or less,
The gap ratio is 0.3 or more and 0.6 or less,
A vibration isolation member made of an inorganic granular material containing an admixture of 0.08% to 10%.   The vibration isolation member according to claim 1, wherein the inorganic particles are limestone powder.   The surface layer processing method of the soft ground which lays the vibration isolator of Claim 1 or 2 on a ground.

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