JP5314484B2 - Construction method of seismic isolation structure - Google Patents

Description

  The present invention relates to a method for constructing a base isolation structure.

  For the purpose of protecting existing structures, there are cases where the ground part of the structure is reinforced and the foundation part is reinforced to improve seismic performance.

  As such a reinforcing method, it is common to improve the ground of the foundation ground of an existing structure. However, the improvement effect may vary due to the non-uniformity of the foundation ground and the uncertainty of the reinforcing effect may be a concern.

  Therefore, as a seismic isolation method for existing structures, the present applicant covers the lower part of the seismic isolation target area including the existing structures with multiple tunnels formed by sharing legs with other adjacent tunnels. In addition, a seismic isolation method has been disclosed that replaces the leg of the tunnel with a seismic isolation device to achieve seismic isolation in a predetermined area (see Patent Document 1).

JP 2005-226393 A

  In the seismic isolation method described in Patent Document 1, a temporary support member is arranged on the leg portion of the tunnel, and the seismic isolation device is arranged only after the load acting on the leg portion is transferred to the support member. Can not. Moreover, since it is necessary to remove this support member after arrangement | positioning of a seismic isolation apparatus, it took the effort for construction.

  This invention makes it a subject to propose the construction method of the base isolation structure which made it possible to easily perform base isolation of an existing structure, without modifying a ground part.

  The construction method of the seismic isolation structure of the present invention that solves such problems includes a shaft construction step of forming a shaft along the side of the seismic isolation target region, and a lower part of the seismic isolation target region using the shaft. A tunnel construction process in which a plurality of rectangular tunnels are arranged side by side; a slab construction process in which a slab that covers the lower side of the seismic isolation target region is formed vertically using the plurality of rectangular tunnels; and A seismic isolation device installation step for installing a seismic isolation device between the upper and lower slabs in an internal space, and a lining removal for removing a portion located between the upper and lower slabs of the rectangular tunnel lining And a process.

According to the construction method of the seismic isolation structure, since the seismic isolation device is installed in the inner space of the rectangular tunnel, the lining constituting the rectangular tunnel can be used as a support member. Therefore, it is possible to easily perform seismic isolation of the seismic isolation target area.
In addition, a slab is formed over the entire area below the seismic isolation target area, and the seismic isolation device is arranged using this slab, so that unequal subsidence etc. can be suppressed and high-quality construction can be performed. .

Further, the lining of the rectangular tunnel is configured by continuously connecting a box having a rectangular cross section in the tunnel axis direction, and the box has an outer shell formed in a rectangular tube shape and a tunnel axis direction. A plurality of main girders arranged in parallel at predetermined intervals, and a plurality of vertical ribs arranged along the tunnel axis direction between the adjacent main girders, and the slab construction step in the main beam in a state where the leaving the construction by removing the said shell corresponding to the reinforcement portions of the slab in line Ukoto, easily the slab monolithic across the rectangular tunnel of plural Can be formed.

  According to the construction method of the seismic isolation structure of the present invention, it is possible to easily perform seismic isolation of an existing structure without modifying the ground portion.

It is a longitudinal cross-sectional view which shows the outline of the seismic isolation structure concerning suitable embodiment of this invention. It is a flowchart which shows the construction method of the seismic isolation structure which concerns on suitable embodiment of this invention. (A) And (b) is a longitudinal cross-sectional view which shows each construction step of the construction method of the base isolation structure. (A) is the cross-sectional view of FIG.3 (b), (b) is the perspective view. It is a perspective view which shows a box. It is a longitudinal cross-sectional view which shows the construction stage of the post process of FIG. (a) is a longitudinal cross-sectional view which shows the construction stage of the post process of FIG. 6, (b) is a cross-sectional view of (a).

Preferred embodiments of the present invention will be described with reference to the drawings.
This embodiment demonstrates the case where the seismic isolation object area | region A containing the existing structure B is seismically isolated using the construction method of the seismic isolation structure of this invention. In addition, the magnitude | size etc. of the seismic isolation object area | region A used as seismic isolation object are not limited.

  As shown in FIG. 1, the seismic isolation structure 1 of the present embodiment includes upper and lower slabs 2 and 3 formed below a seismic isolation target area A including an existing structure B to be seismically isolated, A seismic isolation device 4 installed between the slabs 2 and 3.

  As shown in FIG. 2, the construction method of the seismic isolation structure of this embodiment is a shaft construction process S1, a tunnel construction process S2, a slab construction process S3, a seismic isolation device installation process S4, and a lining removal process S5. And.

  The shaft construction process S1 is a process of forming the shaft 5 along the side of the seismic isolation target region A as shown in FIG.

In this embodiment, the shaft 5 is formed in a rectangular shape in plan view so as to cover the entire periphery of the seismic isolation target region A.
The vertical shaft 5 is not necessarily formed in a rectangular shape in plan view, and may be appropriately set according to the shape of the seismic isolation target region, the arrangement of existing facilities, and the like. In addition, the configuration of the shaft type of the shaft 5 is not limited and may be appropriately formed. Further, in the rectangular shaft 5, the side along the axial direction of the tunnel 6 (a part other than the part used as the start base or the arrival base) may be constructed after the construction of the tunnel 6 and the construction timing. Is not limited.

One side of the vertical shaft 5 formed in a rectangular shape is used as a starting base. The part corresponding to the starting base of the shaft 5 is formed to a size that allows the excavator M (see FIG. 3B) such as a shield machine and a propulsion machine, the box 7 and the like to be carried in.
In addition, when assembling the excavator M in the shaft 5, it is good also as ensuring the extent which can assemble the excavator M only in the bottom part of the location corresponding to the starting base of the shaft 5.

  The shaft 5 is formed in a groove shape along the side of the seismic isolation target region A. The vertical shaft 5 has a depth that allows the tunnel 6 to be formed below the seismic isolation target region A (see FIG. 3B). In the present embodiment, the shaft 5 is formed at a depth that enables excavation of the tunnel at a position deeper than the foundation B1 of the existing structure B. However, the shaft 5 is not necessarily deeper than the foundation B1. Good.

  The side of the vertical shaft 5 that faces the starting base is used as a destination base, and is formed in a shape that allows the excavator M to be carried out.

  The tunnel construction step S2 is a step of constructing the rectangular tunnel 6 using the shaft 5 constructed in the shaft construction step S1, as shown in FIG.

  In this embodiment, as shown in FIGS. 4A and 4B, a plurality of (in this embodiment, five) rectangular tunnels 6, 6,... Cover the side.

  The rectangular tunnel 6 is formed by lining a plurality of rectangular boxes 7, 7,...

In the present embodiment, the tunnel 6 is constructed by excavating the ground G with a shield machine (excavator M) and connecting the boxes 7, 7,. The tunnel 6 may be constructed by a propulsion method, and the construction method of the tunnel 6 is not limited.
Moreover, in this embodiment, although the tunnel 6 shall be formed under the foundation B1 of the existing structure B, for example, when the foundation B1 is a pile foundation, the existing structure of the formation place of the tunnel 6 is used. When the base B1 of B is arranged, the tunnel 6 is constructed while underpinning.

  As shown in FIG. 5, the box 7 is adjacent to an outer shell 7a formed in a rectangular tube shape and a plurality of main girders 7b, 7b,. A plurality of vertical ribs 7c, 7c,... Arranged along the tunnel axis direction between the matching main beams 7b, 7b.

  The outer shell 7a is composed of a plurality of steel skin plates joined by welding, and has a rectangular cross section as a whole.

  The main girder 7b is composed of a plurality of steel plate members arranged in a frame shape along the inner surface of the outer shell 7a, and each plate member is joined to the inner peripheral surface of the outer shell 7a by welding.

The vertical rib 7c is made of a steel plate material joined to the inner peripheral surface of the outer shell 7a by welding. In addition, the edge part of the longitudinal direction of the vertical rib 7c is joined to the side surface of the main girder 7b by welding.
The structure of the box 7 is not limited to the above.

In the present embodiment, the rectangular tunnel 6 is constructed with one side of the vertical shaft 5 as a starting base and the side facing the starting base across the seismic isolation target region as a destination base.
In the present embodiment, when the excavator M reaches the arrival base, the rectangular tunnel 6 adjacent to the previously constructed rectangular tunnel 6 is constructed by unloading from the shaft 5 and carrying it into the starting base. The excavator M changes its direction at the arrival base (right side in FIG. 3B) and excavates in the starting base direction (left side in FIG. 3B), so that the rectangular tunnel constructed in advance. A rectangular tunnel 6 adjacent to 6 may be constructed. Alternatively, a plurality of rectangular tunnels 6 may be excavated simultaneously using a plurality of excavators M.

  As shown in FIG. 6, the slab construction step S3 uses a plurality of rectangular tunnels 6, 6,... Constructed in the tunnel construction step S2 to cover the lower side of the seismic isolation target area A in a plane. 3 is a process of forming 3 vertically.

  In the slab construction step S3, first, the outer shell 7a of the box 7 corresponding to the bar arrangement locations of the slabs 2 and 3 is removed. Next, reinforcing bars are arranged across a plurality of rectangular tunnels 6, 6,..., And slabs 2 and 3 are formed that cross the plurality of rectangular tunnels 6, 6,. reference). At this time, the main girder 7b of the box 7 is left to be used as a support for supporting the own weight of the seismic isolation target region A.

  Concrete walls 2a and 3a are raised at the ends of the slabs 2 and 3, respectively. At this time, the concrete wall 2a of the upper slab 2 and the concrete wall 3a of the lower slab 3 are formed in a state where they are spaced apart from each other, and the ground G other than the seismic isolation target region A and the seismic isolation target region A Isolate. Thereby, even if it is a case where an earthquake motion acts, concrete walls 2a and 3a do not mutually interfere.

In addition, the earth retaining walls 5a and 5b are formed on the vertical shaft 5 formed along the tunnel axis direction with a planar space therebetween. At this time, the earth retaining wall 5 a on the outer peripheral side of the shaft 5 is deeper than the bottom of the shaft 5. On the other hand, the retaining wall 5b on the inner peripheral side of the shaft 5 is formed in a state in which the lower end is in contact with or connected to the upper surface of the rectangular tunnel 6 after the construction of the rectangular tunnel 6 at the end.
The form of the retaining walls 5a, 5b is not limited. Further, the depth of penetration of the retaining wall 5a is not limited, and may be set as appropriate.

  The seismic isolation device installation step S4 is a step of installing the seismic isolation device 4 between the upper and lower slabs 2, 3 constructed in the slab construction step S3, as shown in FIGS. 7 (a) and (b).

The seismic isolation device 4 is installed in the inner space of the rectangular tunnel 6 as shown in FIG.
The number of installations and installation intervals of the seismic isolation devices 4 are not limited and may be set as appropriate.
Moreover, the structure of the seismic isolation apparatus 4 is not limited, for example, a sliding bearing or laminated rubber.

  The lining removal process S5 is located between the upper and lower slabs 2 and 3 in the box 7 (covering) constituting each rectangular tunnel 6 after the seismic isolation apparatus 4 is installed in the seismic isolation apparatus installation process S4. This is a process of removing the part to be performed.

  Thereby, the self-weight of the seismic isolation target area A is supported by the seismic isolation device 4.

  As mentioned above, according to the construction method of the seismic isolation structure of this embodiment, it is possible to construct the seismic isolation structure 1 in the seismic isolation target region A without moving and removing the existing structure B.

  In order to install the seismic isolation device 4 in the inner space of the rectangular tunnel 6 (inside the lining) (see FIG. 7B), the lining of the rectangular tunnel 6 (box 7) during the installation work of the seismic isolation device 4 ) Can be used as support work as it is. That is, according to this embodiment, the support work at the time of installing the seismic isolation device 4 can be omitted or reduced, and thus the labor and cost of separately arranging the support member can be omitted.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and it goes without saying that the above-described constituent elements can be appropriately changed without departing from the spirit of the present invention.

In the above embodiment, after the upper and lower slabs are formed in the slab construction process, the seismic isolation device is installed between the upper and lower slabs, but the slab construction process and the seismic isolation device installation process are performed in parallel. Also good.
That is, after installing the seismic isolation device on the lower slab formed at the lower part of the tunnel, the upper slab may be constructed.

  In the above embodiment, one tunnel is provided side by side. However, a plurality of tunnels may be formed as necessary.

  In the above embodiment, the space between the foundation of the structure and the box is provided and the weight of the structure is supported by the seismic isolation structure through the ground. By receiving with the body, the weight of the structure may be directly supported by the seismic isolation structure.

  Moreover, although the said embodiment demonstrated the case where the excavator excavated from the starting base was collect | recovered from an arrival base, an excavator may be collect | recovered from the inside of a rectangular tunnel. In this case, a retaining wall is formed in the shaft on the reaching side, similarly to the shaft formed along the tunnel axis direction.

1 Seismic isolation structure 2 Upper slab (slab)
3 Lower slab (slab)
4 Seismic isolation device 5 Shaft 6 Rectangular tunnel 7 Box A Seismic isolation target area B Existing structure

Claims (1)

A shaft construction process for forming a shaft along the side of the seismic isolation target region;
Tunnel construction step of juxtaposing a plurality of rectangular tunnels below the seismic isolation target region using the shaft,
A slab construction process for forming a slab that covers the lower side of the seismic isolation target region using the plurality of rectangular tunnels, and
In the inner space of the rectangular tunnel, a seismic isolation device installation step of installing a seismic isolation device between the upper and lower slabs;
Of the lining of each rectangular tunnel, a lining removal step of removing a portion located between the upper and lower slabs, and a construction method of a seismic isolation structure comprising:
The lining of the rectangular tunnel is configured by connecting a box with a rectangular cross section in the tunnel axis direction,
The box is arranged along the tunnel axis direction between the adjacent main girders and the outer main shell formed in a rectangular tube shape, a plurality of main girders arranged in parallel at a predetermined interval in the tunnel axis direction A plurality of vertical ribs, and
In the slab construction process, characterized by the Turkey to remove the outer shell corresponding to the reinforcement portions of the slab in a state of leaving the main beam, method for constructing a seismic isolation structure.

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