JPH09268588A - Seismic retrofitting method for submerged tunnel - Google Patents

Abstract

(57) [Abstract] [Problem] Method for retrofitting an existing submerged tunnel with earthquake resistance,
Providing seismic retrofitting methods for new buried tunnels using the same means as for existing ones. According to a first method, an existing buried tunnel 1 is used.
Both sides are excavated, and buffer blocks 2 that are easily deformed or destroyed by the horizontal force that acts during an earthquake are installed in the excavated portion. In the second method, when a new submerged tunnel is built,
The above-mentioned buffer blocks are installed on both sides thereof. In the third method, both sides and the upper side of the existing submerged tunnel are covered with concrete excluding the joint portion of the submerged tunnel to increase rigidity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic retrofitting method for a submerged tunnel.

[0002]

2. Description of the Related Art Since the Great Hanshin Earthquake, there has been an increasing demand for seismic retrofitting of civil engineering structures and buildings, but seismic retrofitting of conventional submerged tunnels has been done mainly at the time of new construction, and it has been The fact is that it is only carried out on a small scale from inside the tunnel, and it is not enough to deal with a large earthquake.

[0003]

DISCLOSURE OF THE INVENTION The problem to be solved by the present invention, that is, the object of the present invention is, firstly, in view of the above-mentioned circumstances, the existing submerged tunnel can sufficiently withstand a large earthquake. The second purpose is to provide a method for seismic strengthening a new construction by the same means as the existing construction.

[0004]

In order to achieve the above first object, in the first method of the present invention, both sides of an existing submerged tunnel are excavated, and a horizontal force acting on the excavated portion during an earthquake is applied. A buffer block that can be easily deformed or destroyed is installed.

In order to achieve the above-mentioned second object, in the second method of the present invention, when a submerged tunnel is newly installed, a trench whose bottom width is wider than that of the submerged tunnel is excavated, and the center of the trench is excavated. In addition to constructing a submerged tunnel along the section, buffer blocks that are easily deformed or destroyed by the horizontal force acting during an earthquake are installed on both sides of the tunnel.

In order to achieve the same object as the first invention of the present invention, in the third method of the present invention, mountain retaining sheet piles are driven on both sides of an existing submerged tunnel at appropriate intervals, and the inside thereof. After excavating the burial tunnel to expose the submerged tunnel, and erected the top plate between the upper ends of the mountain retaining sheet piles on both sides, remove the seam portion of the burial tunnel in the gap between the mountain retaining sheet pile and the slab and the burial tunnel. , Filled with concrete.

The material of the buffer block used in the first and second methods of the present invention is arbitrary, but is generally made of concrete.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The first method of the present invention is intended to reduce the horizontal seismic force acting on an existing submerged tunnel, and is carried out in the mode illustrated in FIG. It

In FIG. 1, (1) is a stage in which both sides of an existing submerged tunnel 1 are excavated, and (2) is a buffer block 2 which is easily deformed or destroyed by horizontal force acting at the time of an earthquake in the excavated portion. And the step (3) shows the step of backfilling.

In the figure, reference numeral 3 denotes an earth retaining sheet pile placed on one side of the submerged tunnel 1 prior to excavation. Such an earth retaining sheet pile 3 is provided on one side of the submerged tunnel 1 as shown in the figure. It does not matter whether it is set, it is set on both sides, or it is not set at all.

Although the material of the buffer block 2 is arbitrary, it is generally made of concrete. In FIG. 2, two types of buffer blocks made of non-reinforced concrete having cavities 4 and 5 are made of unreinforced concrete. Is illustrated.

Next, the second method of the present invention is the above-mentioned first method.
It is intended to reduce the horizontal seismic force acting on the new submerged tunnel by the same method as in the method of (1). It shows the step of excavating a trench wider than the width and constructing a submerged tunnel along the central part of the trench, and the subsequent work is similar to that of the first method.

In the case of the second method, if a sheet for reducing frictional force (for example, a vinyl chloride sheet) is previously attached to the bottom surface and both side surfaces of the box body of the new submerged tunnel, the seismic resistance will be improved. The effect increases.

Next, the third method of the present invention is intended to enhance the rigidity of the existing submerged tunnel to improve the proof stress against seismic force. In the embodiment illustrated in FIG. Be implemented.

In FIG. 3, (1) is a stage in which pile retaining sheet piles 7, 7 are placed on both sides of the existing buried tunnel 6, and (2) is an excavation inside the pile retaining sheet piles 7, 7 to expose the buried tunnel 6. In the step (3), after the top plate 8 was installed between the upper ends of the mountain retaining sheet piles 7, 7, the mountain retaining sheet piles 7, 7 and the space between the top plate 8 and the box body 9 of the submerged tunnel 6 were installed. This shows a stage in which the concrete 10 for underwater casting is applied and the box 9 is wrapped with the concrete 10 to increase its rigidity.

FIG. 3 (4) shows a cross section of the seam portion 11 (connection portion of the box 9) of the submerged tunnel 6 at the above-mentioned step (3). As is clear from this figure, Since this part is not filled with concrete, its rigidity is small and the performance as a flexible joint is maintained even after reinforcement.

It is preferable that the mountain retaining sheet pile 7 and the top plate 8 are provided with means for securing rigidity and integrally adhering with the concrete 10, and the box 9 is integrated with the concrete 10 so that axial force is not transmitted. Although it is better not to turn it into vinyl, as an example of such means, it is conceivable to attach a vinyl chloride sheet to the exposed surface of the box 9.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first method and a second method of the present invention.

FIG. 2 is a perspective view of two examples of buffer blocks used in the first method and the second method of the present invention.

FIG. 3 is an explanatory diagram of a third method of the present invention.

[Explanation of symbols]

1: Submerged tunnel, 2: Buffer block, 3: Earth retaining sheet pile, 4: Hollow, 5: Hollow, 6: Submerged tunnel, 7: Earth retaining sheet pile, 8: Top plate, 9: Box, 10: Concrete, 1
1: Seam part.

Claims (4)

[Claims] 1. A seismic retrofitting method for a submerged tunnel, which comprises excavating both sides of an existing submerged tunnel, and installing a buffer block in the excavated portion that is easily deformed or destroyed by a horizontal force acting during an earthquake. . 2. When newly constructing a submerged tunnel, a trench whose bottom width is wider than that of the submerged tunnel is excavated, a submerged tunnel is constructed along the center of the trench, and both sides act on an earthquake. A seismic reinforcement method for submerged tunnels, characterized by installing a buffer block that can be easily deformed or destroyed by horizontal force. 3. The seismic reinforcement method for a submerged tunnel according to claim 1, wherein a concrete buffer block is used. 4. An embankment sheet pile is struck on both sides of an existing submerged tunnel at appropriate intervals, the inside is excavated to expose the submerged tunnel, and a top plate is erected between the upper ends of the mountain pile sheet piles on both sides. A seismic reinforcement method for the submerged tunnel, characterized in that after that, the gap between the mountain retaining sheet pile and the top plate and the submerged tunnel is filled with concrete excluding the seam of the submerged tunnel.