JPH10237890A - Structure prepared for ground lateral flow - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the function by constructing an underground wall in the bulkhead side ground of a structure situated near a bulkhead, and constructing an underground wall of a form gradually extended toward the structure side on the upstream side in the direction where the lateral flow of ground to the structure is estimated. SOLUTION: An underground wall 5 is constructed in the ground G on a bulkhead 1 side of a structure 2 situated near the bulkhead 1. On the upstream side of the estimated moving direction of the ground, an underground wall 7 is constructed. The underground wall 7 is formed so as to have a substantially V-shaped plane cross section in which it is curved from a top end part 7a to both side end parts 7b of the structure 2. It is gradually minimized from the upper part toward the lower part to approach the top end part 7a to the structure 2 side. According to such a structure, even when a ground G' is liquefied according to the movement of the bulkhead 1 by earthquake, or the ground G on the opposite side is liquefied, its effect can be prevented from being extended to a foundation 3. Further, the liquefied ground G can be smoothly guided to both the sides. Thus, the term of works and the construction cost can be suppressed to a minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lateral flow control structure suitable for use as a foundation for various structures such as buildings constructed on soft ground, for example, located near a revetment.

[0002]

2. Description of the Related Art As is well known, the foundation of various structures such as buildings constructed on soft ground loses its supporting force when the ground below liquefies due to an earthquake. We use piles that reach the underground hard support layer, and make ground improvements.

By the way, in the 1995 Hyogoken-Nanbu Earthquake, the foundations of structures such as buildings and bridges suffered severe damage even though the above liquefaction countermeasures were taken. did. This damage was due to lateral flow (horizontal displacement) due to liquefaction of the ground, which caused the foundation to move and cause the bridge to fall on the bridge, and the foundation pile to be deformed and damaged in the building. It is clear.

[0004] The damage caused by the lateral flow of the ground is as follows.
In particular, it is remarkably recognized in structures near the revetment. This is because, as shown in FIG. 7, the seawall 1 moves due to the inertial force of the earthquake and the rigidity decrease due to the liquefaction of the ground G, and accordingly, the revetment 1 is dragged by the large lateral flow of the ground G, and the structure 2 Foundation 3 has been determined to have been damaged.

[0005]

However, the above-mentioned conventional techniques have the following problems.
The first way to prevent the lateral flow of the ground G near the revetment 1 is to reinforce the revetment 1 so that it does not move due to the earthquake. However, the owner of the revetment 1 and buildings located near it In many cases, the owner of the structure 2 is not the same, and in this case, the owner of the structure 2 cannot take measures.

For this reason, it is conceivable that the owner of the structure 2 takes measures such as strengthening the ground G by a ground improvement method or the like, but such a method can completely prevent the lateral flow of the ground G. If it is attempted to prevent such problems, both the construction period and construction cost will be extremely enormous. Moreover, even if the above measures are applied to the existing structure 2, the structure 2
In many cases, it is substantially difficult to improve the ground G in the entire area below the ground. When a pile is used as the foundation 3, to avoid the damage due to the lateral flow as described above,
At present, the only way to increase the rigidity of the pile is to increase the diameter of the pile or use a material with high hardness. However, a pile that is not damaged by a strong earthquake such as seismic intensity 7 not only raises costs significantly but also requires a large amount of material. At present, it is difficult to obtain a sufficient pile displacement suppressing effect with the conventional technology.

[0007] The present invention has been made in view of the above points, and to maintain its function without being damaged even if lateral flow occurs due to liquefaction of the ground due to an earthquake or the like. It is an object of the present invention to provide a structure for preventing lateral lateral flow which can be applied to existing structures.

[0008]

The invention according to claim 1 is
As a countermeasure against lateral flow due to liquefaction of the ground due to an earthquake,
A ground wall embedded in a non-liquefied layer is constructed in the ground on the seawall of the structure located near the seawall, and lateral flow of the ground to the structure is expected. Another underground wall is constructed on the upstream side in the same direction, and the other underground wall has a planar shape whose width gradually increases from the upstream side toward the structure side. .

According to a second aspect of the present invention, in the structure for preventing lateral flow of the ground according to the first aspect, the other underground wall has a configuration in which the planar shape decreases from above to below the ground. It is characterized by having.

[0010] The invention according to claim 3 is the invention according to claim 1 or 2.
In the ground lateral flow countermeasure structure described above, the underground wall is
The structure is characterized in that the structure is extended on both sides of a direction in which lateral flow of the ground is expected.

[0011]

FIG. 1 to FIG. 6 show an example of an embodiment of a lateral lateral flow countermeasure structure according to the present invention.
This will be described with reference to FIG.

[First Embodiment] In the following description, portions common to FIG. 7 shown as a conventional example are denoted by the same reference numerals.

As shown in FIG. 1, as a countermeasure against the lateral flow of the structure 2 located near the revetment 1, an underground wall 5 is constructed on the structure 2 in the ground G on the revetment 1 side. Further, an underground wall (other underground wall) 7 made of, for example, concrete or the like is constructed in the ground G on the opposite side.

The underground wall 5, like the underground connecting wall, is formed by improving the ground in a columnar shape and by connecting the ground improvement body or by connecting a columnar sheet pile to the ground. The lower end is sufficiently deepened so as to reach the non-liquefied layer G2 below the liquefied layer G1.

Further, when the seawall 1 moves due to the earthquake and the ground G 'on the side of the seawall 1 is liquefied from the ground wall 5, the underground wall 5, that is, both sides of the underground wall 5, that is, the seawall 1 Considering that there is a difference between the earth pressure on the side of the structure and the earth pressure on the side of the structure 2, the rigidity and strength are set so that the underground wall 5 is not destroyed by this, and that excessive deformation is not caused. . This is because if the underground wall 5 is excessively deformed, a new sliding surface is formed by the underground wall 5.

The underground wall 7 is located on the upstream side in the anticipated direction of movement of the ground G, that is, when the seawall 1 moves to the river or sea side (left side in the figure) due to an earthquake, the ground G becomes the seawall 1 Since it moves to the side, it is constructed in the ground G on the opposite side to the revetment 1, with its lower end portion embedded in the non-liquefied layer G2.

As shown in FIGS. 1 and 2, the underground wall 7 has a shape obtained by cutting a bow of a hull. That is, as shown in FIG. 2, the underground wall 7 has a substantially V-shape when viewed in a plan cross section, and extends from the front end 7 a toward the ends 7 b, 7 b located near both sides of the structure 2. Has a flat cross-sectional shape that is curved with the following curvature. As shown in FIG. 1, the underground wall 7 has a configuration in which the plane cross section gradually decreases from the upper side to the lower side, and the distal end portion 7a approaches the structure 2 as it goes downward. ing.

In the above-described structure for preventing lateral flow of the ground, the underground wall 5 is constructed in the ground G on the side of the revetment 1 of the structure 2 located near the revetment 1 and the ground G The underground wall 7 is constructed on the upstream side in the moving direction. These ground walls 5 and 7 cause the ground G 'on the side of the seawall 1 to be liquefied due to the movement of the seawall 1 due to the earthquake, or the ground G on the opposite side of the seawall 1 to the structure 2 is liquid. Even when the structure 2 is formed, the influence can be prevented from reaching the foundation 3 of the structure 2, thereby improving the earthquake resistance of the structure 2. Moreover, since the underground wall 7 has a shape like a bow of a hull, the liquefied ground G can be smoothly guided to both sides of the structure 2. Furthermore, these underground walls 5 and 7 can be provided independently by the owner of the structure 2 even if the owner of the structure 2 and the revetment 1 are different. Furthermore, since the ground G below the structure 2 is not improved or the foundation 3 is not strengthened, the ground wall 5 may be provided in the ground G outside the structure 2.
The construction period and cost can be kept to a minimum, and it does not matter whether the structure 2 is newly installed or existing.

In the above embodiment, the underground wall 5
Is provided only on the revetment 1 side of the structure 2. However, as shown in FIG. 3, the underground wall 5 ′ is extended and constructed on both the revetment 1 side of the structure 2 and both sides thereof. Structure 2
May be surrounded, so that a high effect can be achieved. Further, the shape of the underground wall 7 is not limited to the above, and for example, as shown in FIG. For example, the flow of the ground G may be pushed back.

Further, it does not matter what form the structure 2 or its foundation 3 has. For example, as shown in FIGS.
It is possible to similarly apply the ground lateral flow countermeasure structure according to the present invention to the pier (structure) 11 of the bridge 10 and the like. 5 and 6, the U-shaped underground wall 5 'is provided, but it is needless to say that the underground wall 5 as shown in FIG. 1 may be provided. . In addition, the underground walls 5, 5 ', and 7 do not need to be made of any material, and can be easily installed at a low cost and in a short construction period. Any one may be used.

[0021]

As described above, according to the structure for preventing lateral flow according to the first aspect, the non-liquefied layer is embedded in the ground on the seawall of a structure located near the seawall. An underground wall is constructed, and another underground wall is constructed on the upstream side of the structure in the direction in which the lateral flow of the ground is expected, and this is from the upstream side to the structure side. It is configured to have a planar shape whose width gradually increases. Further, according to the ground lateral flow countermeasure structure of the second aspect, the other underground wall has a configuration in which the planar shape gradually decreases from above to below in the ground. In addition, according to the ground lateral flow countermeasure structure according to the third aspect, the underground wall is constructed to extend on both sides in the direction in which the lateral flow of the ground is expected. In this way, by providing an underground wall or another underground wall on the revetment side or on the upstream side in the flow direction of the ground, even if the revetment moves due to the earthquake and the ground liquefies with this, The effect can be prevented from reaching the foundation of the structure, which can increase the seismic resistance of the structure. Moreover, the underground wall can be independently provided by the owner on the structure side even when the owner of the structure and the revetment are different. Furthermore, since it is only necessary to provide the underground wall in the ground outside the structure, the construction period and construction cost can be minimized, and furthermore, it does not matter whether the structure is new or existing.

[Brief description of the drawings]

FIG. 1 is a sectional elevational view showing an embodiment of a structure to which a lateral lateral flow countermeasure structure according to the present invention is applied.

FIG. 2 is a plan sectional view of FIG.

FIG. 3 is a plan sectional view showing another example of the embodiment.

FIG. 4 is a plan sectional view showing still another example of the embodiment.

FIG. 5 is an elevational sectional view showing another application example of the ground lateral flow countermeasure structure according to the present invention.

6 is a plan sectional view of FIG.

FIG. 7 is an elevational sectional view showing a state in which a structure subjected to a conventional liquefaction countermeasure is damaged by an earthquake.

[Explanation of symbols]

 Reference Signs List 1 revetment 2 structure 5,5 'underground wall 7,8 underground wall (other underground wall) 11 pier (structure) G, G' ground

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeru Goto 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Shinichi Sakamoto 1-2-3 Shibaura, Minato-ku, Tokyo Shimizu Corporation Inside (72) Inventor Yasuhiro Yasumoto 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation Inside (72) Inventor Nobuo Mori 2-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation

Claims (3)

[Claims] As a countermeasure against lateral flow due to liquefaction of the ground due to an earthquake or the like, an underground wall embedded in a non-liquefied layer in a ground near the seawall of a structure located near the seawall. Is constructed, and another underground wall is constructed on the upstream side in the direction in which the lateral flow of the ground is expected with respect to the structure, and the other underground wall is formed on the structure from the upstream side. A structure for counteracting lateral flow of the ground, characterized in that it has a planar shape whose width gradually increases toward the side. 2. The ground lateral flow countermeasure structure according to claim 1, wherein the other underground wall has a configuration in which the planar shape decreases from above to below in the ground. Structural countermeasures against lateral flow. 3. The ground lateral flow countermeasure structure according to claim 1, wherein the underground wall is constructed to extend on both sides of the structure in a direction in which lateral flow of the ground is expected. Ground lateral flow countermeasure structure characterized by that.