JP2849805B2 - Seismic isolation method for structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various buildings, road and railway bridges, structures such as viaducts, water supply, gas, sewer,
The present invention relates to a seismic isolation method for protecting a common ditch for installing piping of a lifeline for electricity, communication, and other structures from damage caused by earthquake motion.

[0002]

2. Description of the Related Art Conventionally, a seismic isolation bearing device or the like having a vibration damping effect formed of a laminated rubber body or the like is provided on a foundation of a structure or a portion of a floor, and the vibration caused by an earthquake. There is known a seismic isolation method that insulates a structure from damage, maintains the stability of the structure even in the event of a huge earthquake, and protects the structure from damage caused by earthquake motion.

[0003] However, the seismic isolation bearing device used in the conventional seismic isolation method uses a seismic isolation bearing device made of synthetic rubber or the like reinforced by a laminated steel plate at the time of construction or construction of a structural foundation. It had to be installed between the foundation and the foundation ground, and it could not be installed after construction. Of course, the above-mentioned seismic isolation bearing device could not be used for existing structures.

[0004] In addition, the above-mentioned seismic isolation bearing device has a problem that the cost is high and the construction cost rises.

[0005] The present invention has been made in consideration of the above circumstances, and is not limited to the construction and construction of various structures, but also includes the construction,
An object of the present invention is to provide a seismic isolation method for a structure that can be installed even after construction, is inexpensive in terms of cost, and has an excellent seismic isolation effect.

[0006]

In order to solve the above-mentioned problems, the present invention provides a seismic isolator made of a synthetic resin foam mainly composed of styrofoam so as to surround the ground below and outside the structure. This is a seismic isolation method in which the seismic energy of a seismic wave that is buried in a wall shape and that is going to propagate to the structure during an earthquake is absorbed and attenuated by the seismic isolation material, and sediment, sand and gravel etc. It is characterized by filling and increasing the specific gravity of the seismic isolation material as a whole, and preventing the seismic isolation material from lifting due to pore water pressure.

[0007] Accordingly, the vibration energy of the seismic wave propagating near the surface during an earthquake, particularly the vibration energy in the rolling direction, is made of a synthetic resin foam mainly composed of styrene foam embedded so as to surround the ground below the structure. Absorption and damping can be achieved by the compressive deformation of the vibration material and the cushioning effect of the internal bubbles, and large rolls can be prevented. In addition, due to an increase in specific gravity due to the filling of earth and sand, gravel and the like, floating due to underground pore water pressure is prevented.

A seismic isolation material made of a synthetic resin foam mainly composed of styrene foam is closed cell, has excellent moisture resistance, corrosion resistance and durability, and has excellent properties as a material to be buried in the ground. In addition to having tools, it is easy to mold and can be manufactured at low cost, and it is also easy to bury it in the ground around existing structures.

In the above, at the lower part of the foundation of the structure,
By embedding a seismic isolation material made of the above-mentioned synthetic resin foam, it is also possible to absorb and attenuate the vibration energy of seismic waves from the side and below the ground. In this way, the structure is supported on the ground in an isolated state by the seismic isolation material, making it less susceptible to seismic motion, and also effectively absorbing the vibration energy of seismic waves from below the ground due to a direct earthquake.
Damping is possible, and large vertical vibration of the structure can be prevented.

In the above invention, it is easy to form the seismic isolation member with a concave cross section and fill the inside thereof with earth and sand, gravel, etc., which increase the specific gravity.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory longitudinal sectional view of an embodiment of a seismic isolation method according to the present invention, and FIG. 2 is an explanatory plan view of the same, in which structures are schematically shown.

In the figure, (1) is a building such as a house or a structure such as a pier, which is partially buried on the ground (E);
(2) shows the foundation of the structure. (3) is a plate-shaped seismic isolation member made of a synthetic resin foam mainly composed of styrene foam, and is provided in the surrounding ground (E) so as to surround the ground below and outside the structure (1). It is buried so as to form a wall, and the vibration energy of the seismic wave that is going to propagate to the structure during an earthquake is absorbed and attenuated by the seismic isolation material (3).

As a means for burying the seismic isolation material (3), a groove having a required depth is provided in the ground (E) around the construction position of the structure (1).
For example, it differs depending on the structure of the structure, the underground structure, the depth of the foundation, and the like. A trench having a depth of several tens of meters was dug, and a synthetic resin foam as a seismic isolation material (3) foamed into a block having a required thickness was connected to form a wall and installed in the groove. The excavated earth and sand will be buried around and above the base isolation material. In particular, this seismic isolation material (3) can be buried not only at the time of construction of a structure but also at the ground around an existing structure.

Usually, on the seismic isolation material (3) near the surface of the ground,
A cover layer (4) such as sand or cement is provided so that the synthetic resin foam of the material is not directly exposed to the ground surface, so that the foam is not affected by ultraviolet rays. The thickness of the coating layer (4) is set to 30 mm or more in order to prevent the influence of a fire or the like after an earthquake.

Regarding the synthetic resin foam used for the seismic isolation material (3), the size, weight, strength, and properties of the ground (soil, viscosity, water content, etc.) of the structure to be protected, etc. The expansion ratio, thickness and the like may be appropriately selected and carried out. For example, the expansion ratio is set to 20 to 100 times, the size is set to about 1 to 2 m in length × 1 to 2 m in width, and the thickness is set to about 10 cm to 1 m. . Depending on the structure or the ground, it may be selected outside the above range. This synthetic resin foam is closed cell, does not have water absorption, does not impair the vibration absorption effect even if it is buried for a long time, and has good corrosion resistance and durability. Excellent.

By embedding the seismic isolation material (3) as described above, the vibration energy of the seismic wave propagating near the surface during an earthquake, particularly the vibration energy in the rolling direction, is made of a synthetic resin foam surrounding the lower ground. It can be absorbed and attenuated by the compression deformation of the seismic isolation material and the cushioning effect of the internal bubbles,
Large rolling can be prevented.

That is, the ground near the ground surface vibrates due to the earthquake. For example, the ground (E1) outside the buried portion of the seismic isolation member (3) in FIG. 3 becomes the ground (E1) below the structure (1). ), The base material (3) between the lower ground (E2) and the lower ground (E2) is compressed and deformed by the required thickness (B). The horizontal movement is performed by the distance (C) corresponding to (A)-(B), whereby the vibration of the lower ground (E2), that is, the rolling of the structure (1) can be reduced.

The amount of compressive deformation (B) of the seismic isolation material (3)
Varies depending on the expansion ratio of the synthetic resin foam, the thickness molding method, etc., so that the buried depth and thickness of the seismic isolation material made of foam, depending on the properties of the ground, the depth and strength of the foundation of the structure, etc. Appropriately selected magnification and the like are applied, and this compressive deformation absorbs and attenuates vibration energy. In the case where an active fault exists near the structure, the seismic isolation material (3) is buried either in the direction parallel to the active fault or in the direction perpendicular to the active fault, or in both directions. Effectively absorbs and damps vibration energy.

As described above, in addition to the case where the seismic isolation member (3) is merely buried so as to surround the lower ground of the structure (1), as shown in FIG. Basics (2)
It is preferable that a seismic isolation material (3a) made of the same synthetic resin foam as described above is buried in a lower portion of the base material to absorb and attenuate vibration energy of seismic waves from below the ground.

This seismic isolation material (3a) is buried together with the surrounding wall-shaped seismic isolation material (3) when constructing the foundation structure of the structure to be newly constructed. The seismic isolation material (3a) can be provided with a vertical through hole at an arbitrary position in order to reduce buoyancy due to underground pore water. When a foundation pile (6) is cast as shown by a two-dot chain line as a foundation structure, the seismic isolation material (3) is removed except for a place where the pile (6) is cast.
a) may be buried or a through hole may be provided to allow the pile to be driven. In addition, the earth and sand is buried in the portion other than the foundation (2) on the seismic isolation material (3a).

By burying the seismic isolation material (3) also in the lower part of the foundation (2) as described above, the structure (1) is supported on the ground in an isolated state by the seismic isolation material (3). Is less likely to be affected by Also, the vibration energy of seismic waves from below the ground due to a direct earthquake can be effectively absorbed and attenuated, and large vertical vibrations of the structure (1) can be prevented.

In particular, in the case of the present invention, as the seismic isolation material (3) (3a) made of a synthetic resin foam for burying and attenuating the vibration energy of seismic waves as described above, the underground moisture-containing material is used. Considering the case where there is a lot, for example, as shown in FIG. 4, a concave section is formed, and the inside thereof is filled with earth and sand, gravel, etc. (5) to increase the specific gravity of the whole seismic isolation material (3). In addition, the floating of the seismic isolation material (3) due to pore water pressure shall be prevented. In addition, other lifting prevention means may be provided.

Further, as described above, the seismic isolation material (3) (3a)
As connecting means of synthetic resin foam buried as
As shown in FIG. 5 and FIG. 6, a concave portion (6) and a convex portion (7) for connection are formed in required places in the foam, and the concave portion (6) and the convex portion (7) are fitted. In some cases, adjacent foams can be bonded to each other. In addition, bonding can be performed using an adhesive or a bonding tool.

The synthetic resin foam mainly composed of styrofoam used for the seismic isolation material may be a polystyrene-based copolymer or a foam of a mixed resin, in addition to styrene foam alone. Further, in addition to the one molded into a thick plate, a foam molded into a deformed block shape such as a pipe cover may be buried and constructed so as to form a wall. Further, in order to prevent holes from being formed by underground organisms, for example, moles, it is possible to use pre-expanded granules formed by mixing short fibers such as rock wool.

The present invention can be applied not only to structures such as buildings and piers, but also to various other structures such as common trenches for installing pipes of lifelines such as water supply, gas, sewerage, electricity, and communication. .

[0027]

As described above, according to the seismic isolation method of the present invention, since a synthetic resin foam mainly composed of styrene foam is used as the seismic isolation material, it can be used for a house or a building, a pier, a common ditch or the like. It can be installed not only during the construction of various structures but also after the construction, and it can be buried in the surrounding ground for existing structures, and it can easily manufacture seismic isolation materials by molding, Due to the ease of burial construction, the equipment cost is low, and even if a huge amount is required, the equipment cost is low.

In addition, in the event of an earthquake, the compressive deformation of the seismic isolation material made of synthetic resin foam can effectively absorb and attenuate the vibration energy of the seismic wave that is about to propagate to the structure, thereby making the structure safe. Can be protected. In particular, the specific gravity increases due to the filling of earth and sand, gravel and the like, so that the floating of the seismic isolation material due to underground pore water pressure can be prevented and the durability of the seismic isolation effect is excellent.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional explanatory view of one embodiment of a seismic isolation method of the present invention.

FIG. 2 is a schematic sectional explanatory view of the above.

FIG. 3 is an explanatory diagram of a vibration damping state.

FIG. 4 is an explanatory longitudinal sectional view of another embodiment.

FIG. 5 is a schematic perspective view showing another example of the seismic isolation material.

FIG. 6 is an explanatory longitudinal sectional view of the embodiment.

[Explanation of symbols]

 (1) Structure (2) Foundation (3) (3a) Seismic isolation material (E) Ground (E1) Ground outside seismic isolation material (E2) Ground below structure

Claims (3)

(57) [Claims] A quake-absorbing material made of a synthetic resin foam mainly composed of styrene foam is buried in the ground so as to surround a lower part and an outer ground of a structure. Vibration energy is absorbed by the seismic isolation material,
In the seismic isolation method of damping , soil
Filling with sand, gravel, etc. to increase the specific gravity of the seismic isolation material as a whole
A seismic isolation method for structures, characterized in that the seismic isolation material is prevented from lifting due to pore water pressure . 2. A seismic isolation material made of the synthetic resin foam is buried in a lower part of a foundation of a structure to absorb and attenuate vibration energy of seismic waves from the side and below the ground. 2. The seismic isolation method for a structure according to 1. 3. A seismic isolation material made of a synthetic resin foam is formed in a concave shape in cross section, and is filled with earth and sand, gravel, and the like.
The method for seismic isolation of a structure according to claim 1 or 2.