JP2881640B2 - Soil liquefaction prevention method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing liquefaction of a ground, which can prevent liquefaction occurring on a sandy ground during an earthquake and prevent liquefaction of various structures.

[0002]

2. Description of the Related Art Various measures have been proposed to prevent liquefaction of sandy ground.
There is an invention described in Japanese Patent Publication No. 0 (hereinafter referred to as prior art 1). The present invention relates to a process of driving a casing into a sandy ground by using vibration while compacting the sandy ground, and a method of permeating a pipe having a pressure resistance against a predetermined pressure of the ground and having a hole for water permeation formed in a peripheral wall. Inserting a drain pipe covered with a porous filter into a casing, and removing the casing from the sandy ground to leave the drain pipe in the sandy ground.The drain pipe removes excess pore water pressure in the sandy ground. The present invention relates to a method for preventing liquefaction of sandy ground which is reduced by using the method.

Further, the invention disclosed in Japanese Patent Application Laid-Open No. Hei 2-225712 (hereinafter referred to as "prior art 2") has a large number of openings and a ground from the openings in a predetermined section along the longitudinal direction of the sheet pile body. One or more drainage members provided with a filter for preventing intrusion are provided on at least one surface of the sheet pile main body.

[0004]

The invention of the prior art 1 is as follows.
Since the drain pipe and sheet pile must be constructed separately, it is difficult to cope if there are restrictions on the construction time,
There is a problem in workability. Further, the invention of the prior art 2 is capable of shortening the construction time because the steel sheet pile to which the drainage member is previously attached is cast, but the drainage member can be reduced more than the effect of shortening the construction time. Processing and mounting on steel sheet piles are costly and have problems in terms of economy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a method of preventing liquefaction of the ground, which can reduce the construction time by adding a drainage function to a sheet pile, and which is inexpensive and easy to construct. It is intended for that purpose.

[0006]

[Means for Solving the Problems]

(1) The method for preventing liquefaction of the ground according to the present invention comprises connecting a tip end of a casing formed in a tubular shape or a substantially U-shaped cross section with an end face protection member attached to a sheet pile, and connecting the other end of the casing to the other end of the casing. A step of locking a locking member provided on the joined backing plate to the sheet pile and arranging the casing substantially parallel to the sheet pile; and absorbing water into a cylindrical portion formed in the casing or between the sheet pile and the casing. Loading a rod-shaped or cylindrical drain member having water-soluble or water-permeable properties, placing the sheet pile and casing simultaneously in the ground with the drain member loaded, and placing the sheet pile into the sheet pile. And pulling up the caul plate and the casing while leaving the end face protection member and the drain member in the ground.

(2) In the method for preventing liquefaction of the ground according to the above (1), after the sheet pile and the casing are cast into the ground, the sheet is formed into a cylindrical portion formed in the casing or between the sheet pile and the casing. In this case, a drain member is inserted.

[0008]

1A and 1B show an embodiment of the present invention. FIG. 1A is a front view, FIG.
FIG. 2 is an exploded perspective view of FIG. FIG. 3 shows FIG.
(A) BB enlarged sectional view, CC enlarged sectional view, and D-
It is a D expanded sectional view. In the drawing, 1 is a steel sheet pile, 2 is a casing made of a square steel pipe 21 and shorter than the steel sheet pile 1, 3 is fixed to a lower part of the inner surface of the web of the steel sheet pile 1, and an end face protection member to which the lower part of the casing 2 is connected, 4 is The backing plate 5, which is the same as or narrower than the web width of the steel sheet pile 1 and has a shorter length, is a drain member made of, for example, a polyethylene pressure-resistant tube. Hereinafter, each of the above members will be described in detail.

The steel sheet pile 1 is shown in FIGS. 1 to 3 in the case where the steel sheet pile 1 having a substantially U-shaped cross section is used. For example, an H-section steel 11 shown in FIG. 6 and FIG. 7 (a) are shown. H-section steel 1 with sheet pile
2, a steel pipe 13 as shown in FIG. 2 (b), a steel pipe with sheet pile 14 as shown in FIG.
Concrete piles, ready-made reinforced concrete piles, prestressed concrete piles, steel pipe concrete piles, and the like (hereinafter collectively referred to as “concrete piles”) may be used.
Hereinafter, in the present specification, the above-described various sheet piles, steel pipes, piles, and the like are collectively referred to as sheet piles.

The casing 2 uses a rectangular steel pipe 21 having a rectangular cross section in the figure. However, the casing 2 may be formed into a rectangular cross section or a substantially U-shaped or V-shaped cross section by welding a steel plate. Alternatively, a member having an appropriate cross-sectional shape, such as using a channel steel 22 having a substantially U-shaped cross section as shown in FIG. Can be used.

As shown in FIG. 2 and FIGS. 3 to 5C, the end face protection member 3 has an inner shape substantially equal to the outer shape of the casing 2 and has a size such that the outer surface of the casing 2 can fit inside. It has a substantially U-shaped outer surface fitting portion 31 with an open upper portion (outer bag type), and a sharp portion 31a is formed at the lower portion in a triangular or triangular pyramid shape like a bow of a ship. Have been. Note that a cushioning material may be provided inside the end surface protection member 3 so that the distal ends of the casing 2 and the drain member 5 abut.

As shown in FIG. 8, the end face protection member 3 has an outer shape substantially equal to the inner shape of the casing 2,
The inner surface of the casing 2 is large enough to fit the outer surface and has an inner surface fitting portion 32 having a substantially U-shaped cross section with an open upper portion (inner bag type). A rod or the like is welded to provide the abutting portions 33, 33, or further, an L-shaped holding plate 34 is welded to the front surface to form a fitting portion 35 of the casing 2 between the front wall and the like. The lower end of the casing 2 may be formed so as to fit on the outside thereof.

Further, when the end surface protection member 3 is formed in a cylindrical shape, a smooth outer surface fitting portion 31 or inner surface fitting portion 32 may be provided as described above, or the outer surface fitting portion 31 may be provided.
A female screw may be provided on the inner periphery of the housing 2, or a screw may be provided on the outer periphery of the inner surface fitting portion 32, and a corresponding male screw or female screw may be provided on the lower portion of the casing 2 and screwed together. In the above description, the case where the lower portion of the end face protection member 3 is formed to be sharp, but may be formed to be flat.

Such an end face protection member 3 is fixed by welding by contacting the U-shaped opening with the inner surface of the lower part of the web of the sheet pile 1, or is detachably attached by bolts and nuts. In the case of the cylindrical end face protection member 3,
Fixed to the sheet pile 1 by welding directly or through the mounting arm,
Alternatively, it is detachably attached to the sheet pile 1 with bolts and nuts.

The backing plate 4 is plate-shaped, and is provided with a through hole 41 for a wire or the like at the time of pulling up.
A substantially inverted U-shaped locking member 42 is provided on both side edges of the upper portion.
a, 42b are attached by welding. The lower part of the backing plate 4 is integrally joined to the upper part of the casing 2 by welding. In the case where the casing 2 is made of the steel pipe 23, as shown in FIG. 4
May be welded.

The locking members 42a and 42b are attached to the backing plate 4 and locked to the sheet pile 1 as described above to hold the casing 2 substantially parallel to the sheet pile 1. For example, FIG. As shown in (a), locking members 42a, 42b
May be attached to the front surface of the backing plate 4 and locked to the upper end of the sheet pile 1, or, as shown in FIG. Members 42a,
The shape and the mounting position can be changed as appropriate, such as mounting the 42b and locking it at the upper end of the arrow 1.

The drain member 5 is, for example, a water-absorbing or water-permeable rod-shaped or cylindrical-shaped member having a large number of holes 51 formed in a peripheral wall of a pressure-resistant tube made of a synthetic resin such as polyethylene. To prevent intrusion of earth and sand from 51,
For example, as shown in FIG. 8, the filter 52 may be covered with a filter 52 made of synthetic fiber, synthetic resin, stainless steel or the like having water absorbency or water permeability and corrosion resistance. The drain member 5 is not limited to a synthetic resin, but may be formed of a corrosion-resistant metal tube such as stainless steel.

In the present invention comprising the above members, an end face protection member 3 is attached to the lower portion of the inner surface of the sheet pile 1 by welding, screwing, or the like, as shown in FIG. Next, the backing plate 4 joined to the casing 2 is disposed along the inner surface of the web of the sheet pile 1, and the locking members 42a and 42b are locked to the upper end of the sheet pile 1, and the lower end of the casing 2 is It fits into the outer surface fitting portion 31 of the end surface protection member 3 until it hits the inner wall of the sharp portion 31a. Then, the backing plate 4 and the sheet pile 1 joined to the casing 2 are, for example,
As shown in (1), they are gripped by the viblow hammer 7 and are simultaneously driven. Finally, as shown in FIG. 10B, the drain member 5 is inserted into the casing 2. 11, (a) shows the case where the casing 2 is provided on the inner surface side of the web of the sheet pile 1, (b) shows the case where the casing 2 is provided on the outer surface side of the web of the sheet pile 1, and (c) shows the case where the casing 2 is provided. Are provided on both the inner surface and the outer surface of the web of the sheet pile 1.

As shown in FIG. 4, when a channel steel 22 or a V-shaped cross-section steel is used for the casing 2, the opening side is brought into contact with the backing plate 4 and joined by welding.
The lower part is fitted to the end face protection member 3 and the locking member 4
The drain members 5 and 5 may be inserted into the tubular portion formed between the sheet pile 1 (backing plate 4) and the casing 2 by engaging the sheet piles 2a and 42b with the sheet pile 1. Further, in the case of the end face protection member 3 having the inner surface fitting portion 32, the casing 2 may be fitted until the lower end of the casing 2 comes into contact with the contact portion 33, and a screw is provided on the end face protection member 3 and the lower end of the casing 2. In this case, the screws may be screwed together to connect the two.

In integrating each member,
An end face protection member 3 is attached to the sheet pile 1, and a backing plate 4 joined to a casing 2 in which a drain member 5 is previously mounted is engaged with the sheet pile 1, or a drain is attached to the casing 2 to which the end face protection member 3 is attached. The member 5 may be inserted and attached to the sheet pile 1 via the backing plate 4. Further, the casing 2 in which the drain member 5 is inserted in advance may be used.
The end face protection member 3 is attached to the sheet pile 1 and the end face protection member 3 is attached to the sheet pile 1, and the backing plate 4 joined to the casing 2 is locked to the sheet pile 1.

As shown in FIG. 12 (a), the sheet pile 1, the casing 2 and the backing plate 4, the end face protection member 3 and the drain member 5 integrated with the sheet board 1 together with the backing plate 4 as shown in FIG. By being cast, it is buried integrally in the ground. When the driving is completed, as shown in FIG. 12 (b), the backing plate 4 and the casing 2 are pulled out with the sheet pile 1, the end face protection member 3 and the drain member 5 remaining in the ground. At this time, if the backing plate 4 is made to protrude upward from the upper end of the sheet pile 1, the protruding portion can be directly grasped and pulled out. Further, by providing the through-hole 41 such as a wire or the like with a locking metal such as a wire on the backing plate 4, the pull-out operation can be facilitated.

In this case, the backing plate 4 and the sheet pile 1 joined to the casing 2 are simultaneously gripped and driven into the ground,
Since the casing and the casing 2 are integrated, processing and parts for the integration are not required, and a removing operation for separating the sheet pile 1 and the casing 2 after the casting is also unnecessary. Further, since no trace of processing for integrating the sheet pile 1 and the casing 2 (for example, a bolt hole when integrated with bolts) remains in the sheet pile 1, the appearance after the sheet pile construction can be maintained.

By the way, when the casing 2 is pulled out together with the backing plate 4, the drain members 5 and 5 may move up (up). Therefore, in the present invention,
The following countermeasures were taken. That is, as shown in FIG. 8, the inner surface fitting portion 32 is formed in the end surface protection member 3, and a cap 36 having a hook 37 is attached to the upper end thereof. Then, the lower ends of the synthetic fiber filters 52, 52 covering the drain members 5, 5 are wound around the hooks 37 and fixed. Thereby, even if the backing plate 4 and the casing 2 are pulled out, the drain members 5 and 5 are held by the end surface protection member 3 and do not rise.

Also, a cap with a hook may be attached to the lower end of the drain members 5 and 5, and the hook may be engaged with a stopper provided on the end face protecting member 3, or the casing 2 may be, for example, as shown in FIG. As shown in FIG. 4, in the case of an open section made of the channel steel 22, a holding member projecting toward the drain members 5, 5 is attached to the sheet pile 1 at a position corresponding to the top of the drain members 5, 5, and the drain member 5 , 5 may be blocked.

Further, when the lower ends of the drain members 5, 5 are closed by caps or the like, for example, the drain members 5, 5 are made of a steel bar having a diameter smaller than the inner diameter of the drain members 5, 5, and a weight with a wire or the like attached to the upper portion is attached to the drain member. 5 and 5, the tip is settled down, and when the casing 2 is pulled out, it acts as a reaction force to prevent lifting. When the casing 2 is pulled out, the weight is pulled up. Is also good. Also,
If the lower ends of the drain members 5, 5 are not closed, a plate material larger than the outer shape of the drain members 5, 5 is attached to the upper portion of the weight directly or via a wire, and the weight is inserted into the drain members 5, 5. Then, an appropriate means can be used, such as placing the plate material on the top and acting as a reaction force.

In the present invention configured as described above,
Since the drain member 5 is provided near the sheet pile 1 and both are driven into the ground at the same time, construction is easy and the construction period can be shortened. Also, when driving the sheet pile 1,
Since the sheet pile 1, the casing 2, and the end face protection member 3 perform the earth blocking, closing, and compacting of the surrounding ground in parallel, the strength of the ground against liquefaction can be increased.
Furthermore, groundwater flows into the drain member 5 to dissipate the excess pore water pressure generated in the ground, and the high strength sheet pile 1 is provided in close proximity to this to prevent liquefaction damage of various structures. Can be.

In the above-described embodiment, the casing 2 and the end face protection member 3 having the backing plate 4 joined to the inner surface side of the web of the sheet pile 1 are provided, and one or two drain members 5 are inserted into the casing 2. Although such a case has been described, these members may be provided on the outer surface side of the web of the sheet pile 1, or may be provided on both the inner surface side and the outer surface side of the web. Further, the number of the drain members 5 can be appropriately increased or decreased. further,
As shown by broken lines in FIGS. 6 and 7, an appropriate number of drain members 5 can be provided at appropriate locations according to the type and shape of the sheet pile 1.

[0028]

The method for preventing liquefaction of the ground according to the present invention comprises:
The distal end of a cylindrical or substantially U-shaped casing is connected to an end face protection member attached to a sheet pile, and a locking member provided on a backing plate joined to the other side of the casing is engaged with the sheet pile. Stopping and arranging the casing substantially parallel to the sheet pile, and loading a rod-shaped or tubular drain member having water absorbency or water permeability into the tubular part formed in the casing or between the sheet pile and the casing. A step of placing the sheet pile and the casing simultaneously in the ground with the drain member inserted therein, and a step of placing the sheet pile, and then placing the sheet pile, the end face protecting member and the drain member in the ground with the backing plate And the process of pulling up the casing, it is inexpensive and easy to construct, and the construction period can be shortened.

In addition, when driving the sheet pile, the sheet pile, the casing, and the end face protecting member perform earth stopping, closing, and compacting of the surrounding ground in parallel, thereby improving the liquefaction resistance of the ground. it can. Furthermore, the groundwater flows into the drain member to dissipate the excess pore water pressure generated in the ground, and the sheet piles are provided close to this, so that the liquefaction damage of various structures can be prevented.

[Brief description of the drawings]

FIG. 1 is a front view of an embodiment of the present invention and a sectional view taken along line AA of FIG.

FIG. 2 is an exploded perspective view of FIG.

FIG. 3 is an enlarged sectional view of BB, CC, and DD in FIG. 1;

FIG. 4 is an enlarged sectional view corresponding to FIG. 3 of another example of the present invention.

FIG. 5 is an enlarged sectional view corresponding to FIG. 3 of another example of the present invention.

FIG. 6 is a schematic view of another example of the sheet pile of FIG. 1;

FIG. 7 is a schematic view of another example of the sheet pile of FIG. 1;

FIG. 8 is a front view and a side view of another example of the end face protection member and the drain member of FIG. 1;

FIG. 9 is a schematic view showing another example of the locking member of FIG. 1;

FIG. 10 is an explanatory view of a step in an example of the method according to the present invention.

FIG. 11 is an explanatory view showing an example of the driving of the sheet pile and the backing plate in FIG. 10;

FIG. 12 is a diagram illustrating a process of an example of a method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet pile 2 Casing 3 End surface protection member 31 Outer surface fitting part 32 Inner surface fitting part 33 Contact part 34 Holding plate 4 Patch plate 42a, 42b Locking member 5 Drain member 52 Filter

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayoshi Morikawa 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Kawasaki Steel Corporation (72) Inventor Yugo Oka 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Kawasaki (56) References JP-A-9-95932 (JP, A) JP-A-2-225712 (JP, A) JP-A-62-146315 (JP, A) JP-B-6-11990 (JP) , B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) E02D 3/10 103 E02D 5/62

Claims (2)

(57) [Claims] 1. A front end portion of a casing formed in a cylindrical shape or a substantially U-shaped cross section is connected to an end face protection member attached to a sheet pile, and is provided on an abutment plate joined to the other side of the casing. A step of locking a stop member to the sheet pile and disposing the casing substantially parallel to the sheet pile; and having a tubular portion formed in the casing or between the sheet pile and the casing having water absorbency or water permeability. A step of loading a rod-shaped or cylindrical drain member, a step of simultaneously driving the sheet pile and the casing into the ground with the drain member loaded, and a step of driving the sheet pile, and then the sheet pile and an end face. A method for preventing liquefaction of the ground, comprising a step of pulling up the caul plate and the casing with the protection member and the drain member remaining in the ground. 2. The drain member according to claim 1, wherein after driving the sheet pile and the casing into the ground, a drain member is inserted into a cylindrical portion formed in the casing or between the sheet pile and the casing. A liquid prevention method for the ground.