JP3001086B2 - Column structure in underground structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a column structure constructed in an underground structure such as a tunnel.

[0002]

2. Description of the Related Art In structures constructed underground, the acceleration of earthquakes is generally lower in the ground than in the surface of the ground, and the ground vibrates integrally with the surrounding ground.
Damage from earthquakes is often less than on-ground structures. Also in the design, for example, in the case of an open tunnel, load calculation is performed using the ground surface load, soil cover load, earth pressure, water pressure, and the like, and the effect of an earthquake is generally considered as needed.

[0003] However, in the case of a huge earthquake, a large deformation or stress may occur in the underground structure, and the center pillar of the subway station may be sheared and the ceiling slab may collapse.

[0004] As is well known, shear failure of a reinforced concrete column which is constantly subjected to a large axial force due to an earthquake load is extremely brittle, and concrete in the core portion of the column causes explosive collapse, and the strength of the column is reduced. Decrease rapidly. Therefore, in the design of RC columns, it is necessary to improve the earthquake resistance against shear failure by taking measures such as increasing the shear reinforcement and enlarging the column cross section.

[0005]

However, in the case of, for example, a middle pillar in an open-cut tunnel of a subway, it is necessary to secure a space for a power transmission facility and a signal facility as well as a passing space for a vehicle in the tunnel. The space available to architects is severely limited. Therefore, there is an urgent need for a technique for improving the seismic performance against shear failure without increasing the column section.

The present invention has been made in view of the above circumstances, and has as its object to provide a column structure in an underground structure capable of improving seismic performance against shear failure in a limited space. .

[0007]

In order to achieve the above object, a pillar structure in an underground structure according to the present invention comprises a concrete pillar formed of RC or the like and a laminated rubber in series. The composite column is connected to form a composite column, and both ends of the composite column are fixed to the floor and the ceiling of the underground structure, respectively.

[0008] Further, the pillar structure in the underground structure of the present invention,
The composite pillar is configured by disposing the laminated rubber on both ends thereof and disposing the concrete pillar between the laminated rubbers.

Further, the pillar structure in the underground structure of the present invention is as follows:
The composite pillar is configured by arranging the concrete pillar on both sides of the laminated rubber.

In the column structure in the underground structure according to the present invention, when a relative horizontal displacement occurs between the floor and the ceiling in the underground structure due to an earthquake, the composite column also has a relative horizontal displacement. However, most of the horizontal displacement is absorbed by the deformation of the laminated rubber, and the amount of shear deformation applied to the concrete column is greatly reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pillar structure in an underground structure according to the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a vertical sectional view showing a pillar structure in an underground structure according to the present embodiment. As can be seen from the figure, the column structure in the underground structure according to the present embodiment has a composite column 3 formed by connecting laminated rubbers 2a and 2b in series at both ends of a concrete column 1 made of RC or the like. The both ends of the composite column 3 are fixed to a floor 5 and a ceiling 6 of a tunnel 4 as an underground structure, respectively. The tunnel 4 has a reinforced concrete box-shaped ramen structure, and forms an internal space 8 through which a subway vehicle 7 can pass. Further, the composite columns 3 are arranged at a predetermined pitch along a position where the internal space 8 is approximately bisected.

The laminated rubbers 2a and 2b can be constituted by alternately laminating iron plates having a thickness of several mm and natural rubber, for example, and are preferably constructed so as to be deformable by about 10 cm in the horizontal direction. Moreover, the concrete pillar 1 has a laminated rubber 2a,
It is preferable that the anchor bolts for mounting 2b are made of precast in which they are embedded in advance.

When such a tunnel 4 is subjected to an earthquake, the tunnel 4 as a ramen frame generally has a structure shown in FIG.
(a) shows the deformation properties as shown by the solid line, and the ceiling 6 and the floor 5
, A relative horizontal displacement occurs. Then, the composite column 3 also undergoes forced deformation according to the magnitude of the relative horizontal displacement.

In the conventional case where no laminated rubber is provided, as shown in FIG. 2 (b), such a forced deformation is borne by the concrete column 1, and therefore, a large shear strain is applied to the concrete column 1. appear.

However, when the laminated rubbers 2a and 2b are arranged, a part or most of the relative horizontal displacement is absorbed by the deformation of the laminated rubbers 2a and 2b, as can be clearly understood from FIG. The shear deformation generated in the concrete column 1 is reduced or almost disappears.

In FIG. 2, since the rotational displacement occurring at the upper and lower ends of the composite column 3 is taken into consideration, the deformation due to bending remains in the concrete column 1, but the bending rigidity of the floor 5 and the ceiling 6 is reduced. When the rigidity is sufficiently larger than the bending rigidity, the rotational displacement generated at the upper end and the lower end of the composite column 3 is small, and the composite column 3 is subjected to the forced deformation of only the relative horizontal displacement as shown in FIG. Since the horizontal displacement is absorbed by the laminated rubbers 2a and 2b, the concrete column 1 hardly deforms.

As described above, according to the column structure in the underground structure according to the present embodiment, since a part of the composite column is formed of the laminated rubber, the floor and the ceiling of the tunnel are not connected during an earthquake. The relative horizontal displacement occurring therebetween is absorbed by the laminated rubber, and thus the shear deformation occurring in the concrete column can be greatly reduced, or substantially no shear deformation occurs.

Therefore, it is possible to greatly improve the seismic performance against shear failure by using a concrete column equivalent to the conventional one without increasing the column cross section or increasing the shear reinforcement, and the space used on the building side is reduced. This is a particularly useful tool in tightly restricted subway tunnels.

Further, if the concrete pillar of the present embodiment is manufactured in a factory and carried to the site, a tunnel can be constructed or repaired in a short time.

If the column is formed of a steel frame, the above-described relative horizontal displacement can be absorbed by the deformation performance of the steel frame member, but this is not necessarily advantageous in terms of economic efficiency. According to this, it is possible to improve the earthquake resistance at low cost.

In this embodiment, both ends of the composite column are made of laminated rubber. However, as shown in FIG. 4, for example, only the side adjacent to the ceiling 6 may be made of laminated rubber 2a.

Although not particularly mentioned in the above description, the pillar structure according to the present embodiment may be employed in a newly installed subway tunnel or as a means for repairing an existing subway tunnel. . Also, the scope of application is not limited to open-cut subway tunnels, and all underground structures that cause relative horizontal displacement between floor and ceiling during an earthquake, such as subway station buildings and platforms, of course, It is also applicable to road tunnels, shield tunnels and the like.

(Second Embodiment) Next, a column structure in an underground structure according to a second embodiment will be described. The first
Components and the like that are substantially the same as those in the embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the column structure according to the present embodiment, similarly to the above embodiment, a concrete column made of RC or the like and a laminated rubber are connected in series.
(a) As shown in FIG.
Concrete pillars 1a and 1b are arranged on both sides of
3, both ends of the composite column 13 are fixed to the floor 5 and the ceiling 6 of the tunnel 4, respectively.

The laminated rubbers 2a and 2b are preferably provided at a position where the magnitude of the bending moment generated in the composite column 13 upon receiving an earthquake is as small as possible, for example, near the center of the column.

When such a tunnel 4 is subjected to an earthquake, the tunnel 4 as a ramen frame generally has a structure shown in FIG.
(b) shows the deformation properties as shown by the solid line, the ceiling 6 and the floor 5
, A relative horizontal displacement occurs. And the composite pillar 13
Also undergoes forced deformation in accordance with the magnitude of the relative horizontal displacement, but a part of the relative horizontal displacement is absorbed by the deformation of the laminated rubbers 2a, 2b, and the concrete columns 1a, 1b
The shear deformation occurring at the time is reduced or almost no shear deformation occurs.

Since other functions and effects are almost the same as those of the above-described embodiment, detailed description is omitted here. In addition to this, according to the present embodiment, the location of the laminated rubber is bent. Since the position where the magnitude of the moment is small, bending deformation does not occur in the laminated rubber,
Therefore, the laminated rubber can be used in a state close to pure shear.

In this embodiment, two laminated rubbers are arranged adjacent to each other. However, if the relative deformation expected during an earthquake is relatively small, one laminated rubber may be used. Although the location of the laminated rubber is set near the center of the pillar, the position of the inflection point may be checked in advance by stress analysis, and the laminated rubber may be arranged at the inflection point.

[0030]

As described above, the column structure in the underground structure according to the present invention forms a composite column by connecting a concrete column and a laminated rubber formed of RC or the like in series, and forms the composite column. Since both ends are fixed to the floor and the ceiling of the underground structure, the seismic performance against shear failure can be improved in a limited space.

[0031]

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a pillar structure in an underground structure according to a first embodiment.

FIGS. 2A and 2B are diagrams illustrating an operation of a column structure in an underground structure according to the first embodiment in comparison with a conventional structure, wherein FIG. 2A illustrates a deformation property during an earthquake, and FIG. The figure which showed the deformation | transformation property when rubber is not arranged.

3A and 3B are diagrams illustrating the operation of a column structure in an underground structure according to the first embodiment in comparison with a conventional structure, and FIG. 3A illustrates a deformation property during an earthquake without considering floor and ceiling deflections. And (b) is a view showing the deformation properties when no laminated rubber is arranged.

FIG. 4 is a diagram showing a modification of the first embodiment.

5A and 5B are diagrams of a column structure in an underground structure according to a second embodiment, in which FIG. 5A is a vertical cross-sectional view, and FIG. 5B is a diagram illustrating deformation characteristics during an earthquake.

[Explanation of symbols]

 1, 1a, 1b Concrete pillar 2a, 2b Laminated rubber 3, 13 Synthetic pillar 4 Tunnel (underground structure) 5 Floor 6 Ceiling

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) E21D 11/28 E21D 15/00 E21D 11/08

Claims (3)

(57) [Claims] 1. A composite column is formed by connecting concrete columns and laminated rubber formed of RC or the like in series, and both ends of the composite column are fixed to a floor and a ceiling of an underground structure, respectively. Column structure in underground structure. 2. The column structure in an underground structure according to claim 1, wherein said composite column has said laminated rubber disposed at both ends thereof, and said concrete column is disposed between said laminated rubber. 3. The column structure in an underground structure according to claim 1, wherein said composite column has said concrete columns arranged on both sides of said laminated rubber.