JP3619312B2 - Seismic isolation structure of fill dam body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seismic isolation structure for a fill dam body.
[0002]
[Prior art]
The following cases have been reported as examples of damage caused by earthquakes in fill dams roughly divided into three types: uniform type, zone type and surface impermeable wall type.
(1) A crack parallel to the dam axis enters near the top of the levee and induces piping.
(2) The height of the levee sinks and the margin height decreases, increasing the possibility of erosion due to overflow.
(3) Deep slip or shallow slip occurs on the upstream and downstream surfaces of the dam.
(4) Swelling occurs on the dam upstream and downstream slopes.
[0003]
[Problems to be solved by the invention]
The damage described above occurs when the dam body is shaken in the horizontal direction as an elastic body due to an earthquake, causing a greater horizontal acceleration than the foundation ground at the top of the dam, and reducing the plastic force of the dam body. It is.
[0004]
The present invention has been made to solve the above problems, and an object thereof is to provide a seismic isolation structure that can improve the earthquake resistance of the fill dam.
[0005]
Another object of the present invention is to provide a seismic isolation structure for a fill dam body that can damp horizontal vibrations of the fill dam body and has a strong resistance to a shear force generated between the fill materials.
[0006]
[Means for Solving the Problems]
The present invention has been made in view of the above-described object, and the gist thereof is that a layered reinforcing material is embedded in a horizontal multi-stage shape inside a dam body of a fill dam, and the layered reinforcing material is arranged substantially upstream and downstream at a predetermined interval. A seismic isolation structure for a fill dam dam body that is formed by connecting a plurality of extending strip members with strip members extending substantially in the dam axis direction, and connecting layer reinforcing members adjacent to each other in the vertical direction with interlayer connecting members. is there.
[0007]
In the seismic isolation structure for a fill dam bank according to the present invention, a soil material may be disposed around the belt-like member so as to wind it. By arranging the soil material in this way, water can be prevented from penetrating along the belt-shaped member to form a water channel, and further, the frictional resistance of the belt-shaped member against the fill dam material can be increased. Sliding between the belt-like members can be made difficult to occur.
[0008]
In the seismic isolation structure of the fill dam embankment of the present invention, the band member may be formed of a material having a proof strength that does not break due to frictional force or tensile force received from a fill dam material such as soil, gravel, and rock, The layered reinforcing material is formed by arranging strip-like members at appropriate intervals and density so as to constrain deformation to be generated in the fill dam body by an external force such as an earthquake. As such a band-shaped member, for example, a material formed of a material such as vinyl chloride resin or a rubber secondary product and having a thickness of about 10 to 20 mm and a width of about 300 to 500 mm can be employed.
[0009]
Further, in the seismic isolation structure of the fill dam dam body according to the present invention, the interlayer connecting material is interposed between the layered reinforcing materials and acts as a medium for transmitting the stress generated in each layered reinforcing material to the other layered reinforcing materials. For example, the member may be formed in the same shape using the same material as that of the belt-like member.
[0010]
【Example】
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
1 is a cross-sectional view in the upstream and downstream directions showing the seismic isolation structure of the fill dam body of the present invention, FIG. 2 is a cross-sectional view in the dam axial direction of the fill dam in FIG. 1, and FIG. 3 is a plan view of the fill dam in FIG. FIG.
[0011]
1 to 3, the dam body 20 of the central soil impermeable wall type rock fill dam is illustrated as the fill dam dam body to which the seismic isolation structure of the present invention is applied. However, the seismic isolation structure of the present invention is the central soil impermeable structure. The present invention is not limited to the wall-type rock fill dam, and can be applied to a dam body of a fill dam having another configuration. Here, the dam body of the central soil impermeable wall type rockfill dam is formed by disposing a core portion 21 formed by disposing a soil material in the center, and a gravel material disposed on both upstream and downstream sides of the core portion 21. An embankment including a filter portion 22 and a shell portion 23 formed by disposing a rock material on both sides of the filter portion 22 in the upstream and downstream directions.
[0012]
The seismic isolation structure of the fill dam dam body according to the present invention includes a plurality of upstream and downstream direction strips 11a and laminar reinforcing members 11 including dam axial strips 11b that connect these upstream and downstream direction strips 11a in a horizontal multi-stage shape, These layered reinforcing members 11 are connected by an interlayer connecting strip 12.
[0013]
Here, as the upstream / downstream strip 11a, the dam axial strip 11b, and the interlayer connecting strip member 12, a strip-shaped member made of a vinyl chloride resin material and having a thickness of about 10 to 20 mm and a width of about 300 to 500 mm is used. . The upstream / downstream strips 11a are arranged at a predetermined interval so as to extend substantially in the upstream / downstream direction across all the parts inside the fill dam bank body, that is, the core part 21, the filter part 22 and the shell part 23. The dam axial strip 11b extends to the core portion 21 of the fill dam body by connecting all the upstream and downstream strips 11a. Further, the interlayer connecting strip member 12 is arranged so as to connect the dam axial strips 11b of the respective layered reinforcing members 11 at predetermined intervals.
[0014]
The interlayer connecting strip material 12 may be arranged so as to connect the connecting portions between the upstream / downstream strip 11a and the dam axial strip 11b. Further, the upstream / downstream strip 11a and the dam axial strip 11b may be connected by using the horizontal joining material 15 shown in FIG. 4A, and the dam axial strip 11b and the interlayer connecting strip 12 are You may connect using the vertical joining material 16 shown in FIG.4 (b). Furthermore, as shown in FIG. 7, the soil material 21a used for the core portion 21 may be disposed on the upper and lower surfaces and both side surfaces so as to cover the upstream / downstream direction strip 11a.
[0015]
Next, the effect | action of the seismic isolation structure of the fill dam dam body of this invention is demonstrated.
As shown in FIG. 5, when receiving a horizontal force such as an earthquake, the fill dam body 20 vibrates in the horizontal direction as an elastic body, generating the maximum horizontal acceleration at the top of the dam, and the fill dam body 20 is indicated by a dotted line. Shear stress acts to cause slippage on such a surface. This shear stress is further transmitted to the upstream / downstream strip 11a as a tensile stress as indicated by an arrow in FIG.
[0016]
On the other hand, the upstream and downstream direction strips 11a exhibit tensile resistance together with the interlayer connecting strips 12, and the material constituting the fill dam body is restrained by the frictional force through the soil material wound around the surface of the strips 11a. Prevent occurrence.
[0017]
Further, during horizontal vibration of the dam body 20, the strongest horizontal acceleration acts on the uppermost and lowermost strips 11 a, and the uppermost and lowermost strips 11 a are connected to the other layered reinforcing material 11 via the interlayer connection strip 12. Therefore, the stress generated in the vicinity of the dam bank top is transmitted and dispersed to the dam axial strip 11b and the interlayer connecting strip 12, and the horizontal vibration of the bank top part 20b is suppressed and greatly damped. ]
.
【The invention's effect】
In the seismic isolation structure of the fill dam dam body according to the present invention, a layered reinforcing material is formed by connecting strip members extending in the upstream and downstream direction and the dam axial direction inside the dam body, and the layered reinforcing material is disposed on horizontal multistages. Further, since these layered reinforcing members are connected by the interlayer connecting material, a continuous body of reinforcing material composed of the strip-shaped member and the interlayer connecting material is formed inside the bank body. Therefore, even if non-uniform stress is applied in the vertical direction in the dam body due to an external force such as an earthquake, the stress is transmitted and dispersed by the belt-like member and the interlayer coupling material, and each belt-like member and interlayer coupling material Restrains the material that forms the fill dam, and in particular, it can damp horizontal vibrations that occur near the top of the dam.
[0019]
In addition, the strip-shaped member extending in the upstream / downstream direction exhibits a tensile resistance to the shearing force acting on the dam body material, so that it is possible to prevent cracks, subsidence near the ridge top, and slipping and swelling of the dam upstream and downstream surfaces. .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view in an upstream / downstream direction showing a seismic isolation structure of a fill dam bank according to the present invention.
FIG. 2 is a cross-sectional view of the fill dam of FIG. 1 in the dam axis direction.
FIG. 3 is a plan view of the fill dam of FIG. 1;
FIG. 4A is a bonding material for connecting the band-shaped members in the upstream and downstream directions and the dam axis direction, and FIG. 4B is a bonding material for connecting the layered reinforcing material and the interlayer connection material.
FIG. 5 is a schematic cross-sectional view for explaining an external force acting on the seismic isolation structure of a fill dam bank according to the present invention.
6 is a schematic cross-sectional view showing the stress acting on the belt-like member and the interlayer connecting member in the fill dam bank of FIG.
FIG. 7 is a cross-sectional view showing an upstream / downstream strip wound with a soil material.
[Explanation of symbols]
11 Layered reinforcement 11a Up / down direction strip (band-shaped member)
11b Dam axial strip (band-shaped member)
12 Interlayer connection strip (interlayer connection material)
20 Fill dam body

Claims (2)

Layered reinforcing materials are buried in multiple horizontal stages inside the dam body of the fill dam,
The layered reinforcing material is formed by connecting a plurality of band-like members extending substantially in the upstream / downstream direction at predetermined intervals with band-like members extending substantially in the dam axis direction,
A seismic isolation structure for a fill dam embankment in which layered reinforcement members that are adjacent to each other in the vertical direction are connected by an interlayer connection material. 2. The seismic isolation structure for a fill dam body according to claim 1, wherein the belt-shaped member is wound with a soil material.

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