JP2775214B2 - Ground liquefaction prevention 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 structure for preventing liquefaction of a ground.

[0002]

2. Description of the Related Art As a method of countermeasures against so-called liquefaction of the ground, a method has been proposed and implemented based on the respective principles as if it were a hundred flowers.

[0003] Considering protection of structures, liquefaction countermeasures can be classified into countermeasures before construction of structures and countermeasures after construction of structures. The former generally involves compaction,
The solidification method and the injection method are widely applied. In the latter case, a structure enclosing method is generally used.

FIGS. 7 and 8 show an example of such an enclosing method. In the drawings, reference numeral 1 denotes a tank or other existing structure. The foundation ground of the existing structure 1 is connected to a sheet pile such as a sheet pile 2. It is surrounded by the joined ring-shaped partition plate 3.

[0005] The principle of such an enclosing method is that, by being surrounded by a ring-shaped partition plate 3, the rigidity of the ground is increased, the shear strain due to the sediment inside is reduced, and liquefaction is prevented as much as possible. It depends on the way of thinking.

[0006]

However, when the sheet piles 2 and the like are sequentially cast and joined to each other to form the ring-shaped partition plate 3, the partition plate 3 itself has a high rigidity. Is not easily obtained. This is the same even when the ring-shaped partition plate 3 is multiplexed as shown in FIGS.

An object of the present invention is to solve the above-mentioned disadvantages of the prior art and to use a plurality of ring-shaped partition plates formed by connecting sheet piles or the like which are easy to construct. To provide a ground liquefaction countermeasure structure that can effectively increase the rigidity of the ground due to the high rigidity caused by the ground and reduce the shear strain due to the sediment inside the earth due to the earthquake and reliably prevent the occurrence of liquefaction It is in.

[0008]

According to the present invention, in order to achieve the above object, the base ground of a tank or other existing structure is circularly surrounded by a ring-shaped partition plate formed by connecting sheet piles or the like. In the ground liquefaction countermeasure structure, the inner ring-shaped partition plate and the outer ring-shaped partition plate are connected to each other at appropriate intervals by a connecting plate, which is a single plate, and are partitioned into cores. Protecting the inside of the inner ring-shaped partition plate from liquefaction with the inner ring-shaped partition plate and the outer ring-shaped partition plate and the portion partitioned into the core, or, in addition to this configuration, a connecting plate Is a zigzag arrangement between the inner ring-shaped partition plate and the outer ring-shaped partition plate, or the connecting plate is an inner ring-shaped partition plate and an outer ring-shaped partition plate Approximately parallel between It is an gist to be location.

[0009]

According to the first aspect of the present invention, even if the ring-shaped partition plate is a single one, the ring-shaped partition plate basically surrounds the foundation ground of the existing structure in a circular shape. The rigidity of the internal ground can be increased, and the shear strain caused by the earthquake of the internal earth and sand can be reduced to prevent the occurrence of liquefaction. Even if the enclosed ground is liquefied, the hoop tension due to the circular enclosure can prevent the entire ground and the collapse, so that a tough structure can be obtained.

In addition, the ring-shaped partition plates are multiplexed, and a space between the inner ring-shaped partition plate and the outer ring-shaped partition plate is provided by a connecting plate as a single plate at appropriate intervals. Because of the connection, the rigidity of the ring-shaped partition plate itself composed of a combination of the inside and the outside can be increased. Then, the inner and outer ring-shaped partition plates are finely partitioned by a connecting plate, which is a single plate, so that small core-shaped members are densely packed between the inner and outer ring-shaped partition plates. The ground is surrounded by a highly rigid enclosure as a whole by the shape-shaped partition plate and the portion partitioned into the core shape, and the inside of the inner ring-shaped partition plate can be protected from liquefaction.

According to the present invention, a truss-shaped core is formed between the ring-shaped partition plates by arranging the connecting plates in a zigzag shape. According to the invention, the connection plates are arranged substantially parallel to each other between the ring-shaped partition plates, whereby a substantially rectangular core is formed, and the rigidity of each of the core-shaped sections is increased.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show a first embodiment of a structure for preventing liquefaction of the ground according to the present invention, and FIGS.
Similarly, in the figure, reference numeral 1 denotes an existing structure such as a tank, and the foundation ground of the existing structure 1 is circularly surrounded by a ring-shaped partition plate formed by joining sheet piles such as sheet piles 2.

[0013] The ring-shaped partition plate of the present invention is a multiplex of an inner partition plate 3a and an outer partition plate 3b,
The inner partition plate 3a and the outer partition plate 3b were connected at appropriate intervals by a connecting plate 4 as a single plate.
Thus, the inner partition plate 3a and the outer partition plate 3b
Is divided into a core by being connected by the connection plate 4.

FIG. 5 shows the details, but the connecting plate 4 may be a single plate as described above. For example, a sheet pile 2 or the like can be used. The sheet pile 2 forming the inner partition plate 3a and the sheet pile 2 forming the outer partition plate 3b are connected to each other via a joint 5 provided on the sheet pile 2.

As shown in the figure, a joint 5 for connecting the connecting plate 4 is provided at a central portion of the sheet pile 2 at a fixed angle, as shown in the figure, and the connecting plate 4 is positioned relative to the inner partition plate 3a and the outer partition plate 3b. The sheet piles 2 adjacent to each other are joined instead of the sheet piles 2 facing each other.

In this way, the connecting plate 4 is arranged in a zigzag manner on the inner partition plate 3a and the outer partition plate 3b, and a core type ring having a truss structure is formed as a whole.

FIGS. 3 and 4 show a second embodiment of the present invention. The connecting plate 4 has a size substantially equal to the size of one of the inner partition plate 3a and the outer partition plate 3b. The inner partition plate 3a and the outer partition plate 3b
They are arranged between them and substantially parallel to each other.

In order to achieve this, as shown in FIG. 6, the sheet piles 2 are parallel to each other, but are joined at right angles by a connecting plate 4 at the center, and the connecting plate 4 becomes a web. It is sufficient to use a substantially H-shaped sheet pile having a flange.

In both the first embodiment and the second embodiment, a drain material or the like is provided between the inner partition plate 3a and the outer partition plate 3b partitioned by the connecting plate 4 to have a drainage function. It is also possible.

[0020]

As described above, the liquefaction countermeasure structure of the present invention uses multiple ring-shaped partition plates formed by connecting sheet piles or the like which are easy to construct. The rigidity of the ground can be effectively increased by the high rigidity due to the mutual combination, and the shear strain caused by the sediment inside the earth due to the earthquake can be reduced to reliably prevent the occurrence of liquefaction.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of a ground liquefaction countermeasure structure of the present invention.

FIG. 2 is a vertical sectional side view showing a first embodiment of a structure for preventing liquefaction of the ground according to the present invention.

FIG. 3 is a plan view showing a second embodiment of the ground liquefaction countermeasure structure of the present invention.

FIG. 4 is a vertical sectional side view showing a second embodiment of the ground liquefaction countermeasure structure of the present invention.

FIG. 5 is a plan view of a sheet pile used in the first embodiment.

FIG. 6 is a plan view of a sheet pile used in a second embodiment.

FIG. 7 is a plan view showing a conventional example.

FIG. 8 is a vertical sectional side view showing a conventional example.

FIG. 9 is a plan view showing another conventional example.

FIG. 10 is a vertical sectional side view showing another conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Existing structure 2 ... Sheet pile 3 ... Partition plate 3a ... Inner partition plate 3b ... Outer partition plate 4 ... Connecting plate 5 ... Joint

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E02D 31/08 E02D 27/34

Claims (3)

(57) [Claims] 1. A ground liquefaction countermeasure structure in which a base ground of a tank or other existing structure is multiply surrounded by a ring-shaped partition plate formed by connecting sheet piles or the like in a multi-layered structure. The plate and the outer ring-shaped partition plate are connected to each other at appropriate intervals by a connecting plate, which is a single plate, and divided into cores, and the inner ring-shaped partition plate and the outer ring-shaped partition are separated. A ground liquefaction countermeasure structure, wherein the inside of the inner ring-shaped partition plate is protected from liquefaction at the portion divided into the plate and the core. 2. The ground liquefaction countermeasure structure according to claim 1, wherein the connecting plate is disposed in a zigzag manner between the inner ring-shaped partition plate and the outer ring-shaped partition plate. 3. The ground liquefaction countermeasure structure according to claim 1, wherein the connecting plate is disposed substantially in parallel between the inner ring-shaped partition plate and the outer ring-shaped partition plate.