JP2000192469A - Cofferdam device used for double wall cofferdam construction method, and double wall cofferdam construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently resist earth pressure without particularly increasing the sections of coffering materials even when a ground surface on the front side is deepened and earth pressure from filled sand charged among the coffering materials by steel sheet piles or the like is augmented when a part under a water surface is to be coffered by a double wall cofferdam construction method, to facilitate handling, reduce the manufacturing cost of the coffering materials, and to improve workability. SOLUTION: The cofferdam device is used for the double wall cofferdam construction method, in which coffering materials such as steel sheet piles 11 or the like driven in two rows at intervals are connected mutually by tie materials. Binding sections 3a-3c for PC steel wires 1a, 1b as the tie materials are installed to the coffering materials 11 at a plurality of places along the height direction of the coffering materials, and connected to fixing sections, where a plurality of these binding sections are interlocked mutually and bound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double cutoff method and a double cutoff method used in a construction work in a water area such as a river or a bay.

[0002]

2. Description of the Related Art In the case of constructing a structure foundation or the like below the water surface in a water area such as a river or a bay, there is a method of performing such a construction in a dry manner. In this case, the construction site is closed and cut off from surrounding water, and a double closing method has been conventionally known as a method of closing.

In this double cutoff method, as a temporary cutoff, for example, as shown in FIG. 12, cutoff materials made of steel pipe sheet piles or steel sheet piles 11 are placed in two rows at intervals on the ground 12 at the bottom of the water, and The part of the head of the steel sheet pile 11 projecting upward is mutually connected by a tie rod 13 as a tie material, and a filling sand 14 is injected between the two rows of steel sheet pile 11 as a resistance to water pressure. is there.

[0004] In this way, the area closed by the double steel sheet pile 11 and cut off from the water is dried to construct a structural foundation or the like at this location. In this case, as shown in FIG. 13, the steel sheet pile 11 receives the earth pressure of the internal filling sand 14 from the inside to the outside, and resists the earth pressure from the outside to the inside. The upper part receives the force from the tie rod 13. In addition, the double cutoff method is used not only for underwater cutoffs, but also for double cutoffs using embankment, and the upper part of the embankment may be used as a road.

[0005]

In the double closing method,
When the ground surface on the front side becomes deeper, it is necessary to increase the interval between the cutoff members made of steel sheet piles in order to secure the overall stability. Therefore, the amount of filling sand is increased, and the earth pressure acting on the steel sheet pile and the tension acting on the tie rod are also increased.

For this reason, when the ground surface on the front side is deepened, the cross section of the steel sheet pile 11 and the diameter of the tie rod have been increased in order to resist a large earth pressure from the filling sand 14. As a result, the manufacturing cost of the steel sheet pile 11 increases, and handling such as transportation becomes troublesome in order to increase the weight and volume.

SUMMARY OF THE INVENTION An object of the present invention is to solve the disadvantages of the prior art, and when closing off by the double closing method, the ground surface on the front side becomes deeper and the sand from the filling material inserted between the closing materials such as steel sheet piles is used. Even if the earth pressure becomes large, it can withstand the earth pressure sufficiently without making the cross section of the cutoff material particularly large,
An object of the present invention is to provide a double cutoff method and a double cutoff method which can be easily handled, can reduce the production cost of the cutoff material, and can be easily used.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention firstly provides a double cut-off for connecting cut-off materials such as steel sheet piles which are placed in two rows at intervals with a tie material. A closing device used in a construction method, wherein a plurality of binding portions of a tie material are provided on a plurality of locations along the height direction of the closing material, and the plurality of binding portions are connected to a fixing portion which is tightly coupled in a mutual manner. The gist is that it has been done.

Second, the tie material is composed of a wire material such as a PC steel wire, and has a gist that the tie material is staggered between opposing cutoff materials.

Third, the tie material is composed of two wires, such as PC steel wires, and is to be crossed between opposing cut-off materials so as to be staggered.

Fourth, the tie material is made of a wire such as a PC steel wire, and a roller is provided at a middle portion among a plurality of binding portions provided on the cut-off material, and the wire is wound around the roller in the middle of the wire. It is intended to be turned.

Fifthly, the gist of the present invention is to extend the wire between a pair of mounting members and detachably mount the mounting member to the closing member.

Sixth, shut-off members such as steel sheet piles are placed in two rows at intervals, while a wire member such as a PC steel wire is staggered between a pair of opposed mounting members. The gist is that the member is attached to the shutoff member while being lowered from the upper part to the lower part, and a wire is stretched between the shutoff members.

According to the first aspect of the present invention, since the tie material is provided at a plurality of locations along the height direction of the shutoff material such as a steel sheet pile, the tie material is punched in two rows at intervals. It can resist earth pressure applied to the cutoff material from the filling sand injected between the cutoff materials at a plurality of locations. Therefore, even if the ground surface on the front side becomes deep, it is possible to cope with the earth pressure without particularly increasing the cross section of the cutoff material. In addition, since tying at multiple tying parts can be performed by tying work at one fixing part, even if there are multiple tying parts, tying work at each place is unnecessary, and the whole The workability is good because it can be tied to.

According to the second aspect of the present invention, in addition to the above function, the tie material is made of a wire such as a PC steel wire.
Since it is sufficient that one wire is alternately hooked to the opposing cutoff material such as a steel sheet pile, it can be easily tied to a plurality of locations.

According to the third aspect of the present invention, a first aspect is provided.
In addition to the operation of the present invention described above, by crossing a wire such as two PC steel wires between the opposing cutoff materials in a staggered manner, a force that pulls the opposing cutoff materials inward toward each other is obtained. Can be applied reliably and in a well-balanced manner, and can sufficiently and surely resist the earth pressure caused by the filling sand.

According to the fourth aspect of the present invention, in addition to the above-described operation, by winding a wire such as a PC steel wire around a roller provided on the cutoff member, the wire can be easily hooked on the cutoff member. Instead, it is possible to tension the entire wire by simply pulling one end of the wire, and to apply an inward pulling force to the entire cutoff material.

According to the fifth aspect of the present invention, in addition to the above-described operation, the wire can be easily spanned between the pair of mounting members, and the mounting member can be detachably mounted on the closing member, so that the wire can be easily formed. Can be attached to cut-off materials.

According to the sixth aspect of the present invention, as a construction method, when the wire is attached to the shutoff member, the wire is stretched in advance on a pair of opposed attaching members, and the wire is stretched. Since it is only necessary to lower the mounting member from the upper part to the lower part and attach it to the shutoff member, workability is improved.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 10 is a front view of an embodiment of the double cutoff method of the present invention and a cutoff device used in this method. In the drawing, the same components as those of the conventional example shown in FIG. 12 are denoted by the same reference numerals. It is.

The double cut-off method of the present invention has the same basic construction as that of the prior art, in which cut-off materials made of steel sheet piles 11 are placed in two rows at intervals, for example, on the ground 12 at the bottom of the water. In between the steel sheet piles 11 facing each other, two PC steel wires 1a and 1b are used as tie members for connecting the steel sheet piles 11 to each other. Such wires are staggered and stretched.

As shown in detail in FIGS. 3 to 6, the structure for extending the PC steel wires 1a and 1b to the steel sheet pile 11 is provided as an attachment member to the steel sheet pile 11, for example, separately from the steel sheet pile 11. A T-shaped CT steel 2 manufactured by cutting a web portion of a well-known H-section steel is used, and a PC steel wire 1 is arranged in the longitudinal direction of the CT steel 2.
The binding portions 3a, 3b, 3c of a, 1b are provided at a plurality of locations (three locations in the illustrated example) at appropriate intervals.

The binding portions 3a and 3b located at the upper end and the lower end have the same structure, and as shown in FIGS. 5 and 6, the two mounting plates 4a and 4a sandwich the web 2a of the CT steel 2 from both sides. The base of 4b is fixed by welding or the like, and the tip of the base is projected from the CT steel 2. This plate 4a,
4b has a triangular shape as shown in FIG. 6 or a triangular shape as shown in FIG. 5 so that the tip surface is orthogonal to the direction in which the PC steel wires 1a and 1b are stretched.
As shown in the figure, the tip was formed obliquely cut into a rectangular shape.

Incidentally, the plate is not limited to the two plates as described above, and the base for attachment to the web 2a is integrated, and a groove for inserting the web 2a is provided here. May be.

The binding portion 3c located in the middle is shown in FIGS.
As shown in the figure, two mounting plates 5a and 5b are fixed to the web 2a by welding or the like so that the tips protrude from the web 2a so as to sandwich the web 2a of the CT steel 2 from both sides, and these plates 5a and 5b The roller 6 is provided in the gap formed between the protruding portions. In this case, PC is provided between the roller 6 and the tip of the web 2a.
A gap is provided to allow the steel wires 1a and 1b to be inserted.

On the other hand, a fixing plate 8 is attached to the ends of the PC steel wires 1a and 1b so as to penetrate the PC steel wires 1a and 1b, and a portion protruding from the fixing plate 8 is formed in the screw portion 7. Then, a tightening nut 9 is attached to the base of the screw portion 7.

In order to perform a cutoff work in a water area such as a river or a bay by using such a double cutoff device, one of the steel sheet piles 11 which is a cutoff material as shown in FIGS. A channel-shaped joint 10 is attached to the side surface in the length direction by welding or the like. In this case, since the lower part of the steel sheet pile 11 is driven into the ground 12 at the bottom of the water, the steel sheet pile 11 is mounted above the lower part.

The steel sheet piles 11 to which the joints 10 are attached are placed in two rows on the ground 12 at the bottom of the water so as to face each other at an interval, and the head is projected above the water. At this time, the joints 10 should face each other.

On the other hand, as shown in FIG.
Tightening parts 3a, 3b, 3c provided on T steel 2
The C steel wires 1a and 1b cross each other and are staggered so as to wipe between the opposed CT steels 2. That is, for example, for one PC steel wire 1a, the upper end and the lower end thereof are fixed to the upper and lower binding portions 3a, 3b of one CT steel 2, respectively, and the intermediate portion is located at the intermediate position of the other CT steel 2. Hooks on part 3c. Note that the PC steel wires 1a and 1b are further fixed to the upper binding portion 3a by temporarily fixing, and the PC steel wires 1a and 1b are further projected above the water from the binding portion 3a. 1b is connected to a fixing unit using a jack or the like that pulls 1b.

As shown in FIGS. 5 and 6, the fastening of the PC steel wire 1a to the upper and lower binding portions 3a and 3b is performed.
b, the screw 7 at the tip is inserted between the plates 4a and 4b, the fixing plate 8 is brought into contact with the ends of the plates 4a and 4b, and the nut 9 is tightened in this state. 4b, and the PC steel wire 1a is fixed to the binding portions 3a, 3b.

As shown in FIG. 4, the fastening of the PC steel wire 1a to the intermediate binding portion 3c is performed by either the upper or lower binding portion 3a, 3b.
Before fixing the PC steel wire 1a to the PC steel wire 1a,
May be wound around the roller 6. The same is performed for the other steel wire 1b.

The two PC steel wires 1 are connected to the binding portions 3a, 3b, 3c provided on the pair of opposed CT steels 2 in this manner.
a and 1b are each stretched in a crossing state of a horizontal V-shape.
Accordingly, the CT steel 2 on which the PC steel wires 1a and 1b are stretched is inserted into a joint 10 attached to a steel sheet pile 11 as shown in FIGS. 7 and 8 as a second step. This insertion is CT
This is performed by inserting a portion of the flange 2b of the steel 2 into the groove of the joint 10 from above.

By inserting the CT steel 2 into the joint 10 as described above, if the PC steel wires 1a and 1b are disposed between the steel sheet piles 11 which are driven apart from each other, the following process is performed. As shown in FIG. 9, as a third step, the PC projecting from the upper binding portion 3 a projecting above the water surface
The steel wires 1a, 1b are further pulled to simultaneously tighten all of the plurality of binding portions 3a, 3b, 3c at once, and finally settle to the binding portions 3a.

Finally, as a fourth step, as shown in FIG. 10, a filling sand 14 is put between the steel sheet piles 11 facing each other. This completes the double cutoff.

In such a double cut-off, as shown in FIG. 11, two PC steel wires 1a and 1b are fastened to the steel sheet pile 11 at a plurality of locations in the height direction, in this embodiment at three locations. Therefore, it is possible to resist the earth pressure from the inside to the steel sheet pile 11 due to the filling sand at a plurality of locations from the outside of the steel sheet pile 11. In addition, although the embodiment described above is a case where the double cutoff is performed in water, the present invention is not limited to this, and the present invention can also be performed with a double cutoff by embankment. Can be used as a road.

[0036]

As described above, the cutoff device and the double cutoff method used in the double cutoff method of the present invention are a double cutoff method in which cutoff materials such as steel sheet piles are placed in two rows at intervals. In the case of closing below the water surface, even if the ground pressure on the front side becomes deep, the cross section of the cutoff In particular, it can withstand the earth pressure without increasing the size, it is easy to handle, and the manufacturing cost of the shutoff material can be reduced. Since the fastening operation can be performed by the fastening operation at the fixing unit, even if there are a plurality of fastening portions, the fastening operation is not required for each location, and the entirety can be fastened at once, so that the workability is good.

[Brief description of the drawings]

FIG. 1 is a front view showing a first step of an embodiment of a double closing method according to the present invention.

FIG. 2 is a plan view showing a first step of the embodiment of the double cutoff method of the present invention.

FIG. 3 is a front view of a main part of the double cutoff device of the present invention.

FIG. 4 is a cross-sectional plan view of an intermediate binding portion, which is a main part of the double cutoff device of the present invention.

FIG. 5 is a front view of a binding portion at an end which is a main part of the double cutoff device of the present invention.

FIG. 6 is a perspective view of a binding portion at an end which is a main part of the double cutoff device of the present invention.

FIG. 7 is a front view showing a second step of the embodiment of the double cutoff method of the present invention.

FIG. 8 is a plan view showing a second step of the embodiment of the double cutoff method of the present invention.

FIG. 9 is a front view showing a third step of the embodiment of the double cutoff method of the present invention.

FIG. 10 is a front view showing a fourth step of the embodiment of the double cutoff method of the present invention.

FIG. 11 is an explanatory view of a force applied to the double cutoff device of the present invention.

FIG. 12 is a front view of a conventional double cutoff method.

FIG. 13 is an explanatory diagram of a force applied to a conventional double cutoff device.

[Explanation of symbols]

1a, 1b: PC steel wire 2: CT steel 2a: Web 2b: Flange 3a, 3b, 3c: Tightening portion 4a, 4b: Plate 5a, 5b: Plate 6: Roller 7: Screw portion 8: Fixing plate 9: Nut 10 ... Joints 11 ... Steel sheet piles 12 ... Ground 13 ... Tie rods 14 ... Filled sand

Claims (6)

[Claims] 1. A cut-off device used in a double cut-off method for connecting cut-off materials such as steel sheet piles, which are placed in two rows at intervals, to each other with a tie material. A closing device used in a double closing method, wherein a plurality of tying portions of tie material are provided along a plurality of locations, and the plurality of tying portions are connected to a fixing portion which is tied in conjunction with each other. 2. The tie is made of a wire such as a PC steel wire.
The shut-off device used in the double shut-off method according to claim 1, wherein the shut-off device is staggered between opposing cut-off materials. 3. The double cutoff method according to claim 1, wherein the tie material is composed of two wires, such as PC steel wires, and is crossed between the opposing cutoff materials in a staggered manner. The cut-off device to use. 4. The tie is made of a wire such as a PC steel wire.
The double closing method according to any one of claims 1 to 3, wherein a roller is provided at an intermediate position among the plurality of binding portions provided on the closing material, and a wire is wound around the roller in the middle of the wire. The cut-off device to use. 5. The shut-off device used in the double shut-off method according to claim 1, wherein the wire is stretched between a pair of mounting members, and the mounting member is removably mounted on the shut-off member. . 6. Closing members such as steel sheet piles at intervals.
On the other hand, a wire such as a PC steel wire is hung in a staggered manner between a pair of opposed mounting members, and the mounting members are mounted on the closing member while being lowered from the upper part to the lower part. A double closing method characterized by stretching a wire rod.