JP2931476B2 - How to cut the head of an underground continuous wall - 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 cutting the head of a continuous underground wall.

[0002]

2. Description of the Related Art An underground continuous wall constructed underground is constructed by placing a reinforcing steel cage in an underground excavation hole and casting concrete. The borehole is filled with a bentonite solution to prevent collapse of the inner wall of the borehole. Then, concrete is poured in the filled state, so that after the concrete has cured and hardened, the bentonite solution is mixed in the head of the underground continuous wall, and the strength and the like are insufficient. For this reason, this head must be cut off.

[0003] In addition, this shaving is necessary for connecting the underground continuous wall to another concrete structure so as to expose a reinforcing bar from concrete.

[0004] In this shaving method, first, a sleeve is attached to a reinforcing bar before concrete is cast, concrete is cast and cured, and then the head is exposed. Then, a crusher is inserted into the sleeve provided on the head to split the sleeve (Japanese Patent Application Laid-Open No. 62-90443, 63-308113).

[0005] The crusher is a wedge called a wedge having a thinned tip.

[0006]

However, when such a wedge is used, a sufficient crack is not formed as shown in FIG. That is, when the wedge 2 having a thinned tip is driven into the sleeve 5, the upper figure (wedge 2
(Cross-sectional view parallel to the longitudinal direction of the concrete), the crushing force was not applied to the tip portion, and a deep portion of the concrete, which did not split, occurred. In addition, as shown in the lower drawing (a cross-sectional view orthogonal to the longitudinal direction of the wedge 2), the crack (the dotted line portion in the drawing) enters substantially all directions around, and the energy at the time of driving is dispersed. For this reason, a sufficiently deep crack was not formed in the direction to be split, and efficient splitting could not be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended to cut the head of a continuous underground wall in which a sufficiently deep crack is formed in the direction to be split and efficient splitting can be performed. The aim is to provide a method.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method of placing concrete in an underground excavation hole by placing a reinforcing steel cage and placing concrete to construct an underground continuous wall. Attach the sleeve to the front reinforcing bar, cast concrete and cure it, then expose the head of the underground continuous wall, insert a crusher into the sleeve of this head, split it, and grind the head In the method for sharpening a head of a continuous wall, the crusher is configured to store a bag inside a vertically divided cylindrical outer shell and expand the outer shell by expanding the bag by hydraulic pressure. The crusher is arranged so that the direction of the vertical splitting matches the direction of the splitting. In addition, concrete was placed in a steel cage in an underground excavation hole.
When constructing an underground continuous wall,
Attach the sleeve to the rebar, cast concrete and cure
After exposing the head of the underground continuous wall,
Insert a crusher into the sleeve to split it and sharpen the head
The method for sharpening the head of an underground continuous wall, comprising:
Stores the bag inside the cylindrical outer shell divided vertically,
The body is inflated by hydraulic pressure and the cylindrical outer shell is divided vertically
Slidable wedges provided at both ends of the internal space
To expand the cylindrical outer shell divided vertically.
And the direction of the vertical split is matched with the direction to split.
A crusher is arranged .

[0009]

[Effect] The deep part of the underground continuous wall can also be split efficiently. Also, if the direction of the vertical split of the outer shell is made to match the direction to be split, when the bag body expands due to hydraulic pressure and pushes the outer shell, it will be sufficiently along the vertical split of the outer shell. A deep crack can be obtained, and it is possible to prevent an unnecessary crack from being generated in another direction and dispersing energy.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

The concrete structure in this embodiment is an underground continuous wall. As shown in FIG. 1 to FIG. 3, a steel cage 3 is placed in an excavation hole 1 excavated in the ground. A sleeve 5 for inserting a crusher is attached to the reinforcing cage 3 in a horizontal direction and a vertical direction. A large number of the sleeves 5 are attached, and the purpose is to split the head of the underground continuous wall, which is a concrete structure, so that it can be cut into blocks of a predetermined size.

The sleeve 5 is, for example, a cylindrical shape made of vinyl chloride, and is squeezed with a simple securing band 7 to the main reinforcement of the reinforcing basket 3 or the like. The simple shackle band 7 is made of nylon insulation lock so that the squeezing force is not too strong. Both ends of the sleeve 5 are drilled holes 1
Located near the hole wall. As a result, after the concrete is cast, it is located near the surface of the concrete. Both ends are covered with a styrofoam cap 9. The cap 9 has a short columnar shape having a cross section larger than that of the sleeve 5.

The main reinforcement 8 of the rebar cage 3 is covered with a rim sleeve 10. This edging sleeve 10 is present only in the portion of the underground continuous wall that is cut off.

As described above, the reinforcing cage 3 to which the sleeve 5 covered with the cap 9 is attached is inserted into the excavation hole 1 (FIG. 1).
(Fig. 3), concrete 11 is cast (Fig. 4). In general, the excavation hole 1 is filled with a bentonite solution so that the hole wall does not collapse, and the poured concrete 11 is replaced with the bentonite solution. Bentonite solution, which is lighter than concrete, moves above the borehole 1. Above this, a part of the bentonite solution is mixed into the concrete 11. Due to this mixing, the strength and the like of the concrete 11 become insufficient. After the concrete 11 is cured and hardened, the head 13 of the underground continuous wall is excavated and exposed (FIG. 5).

If the surface of the concrete 11 is hit with a hammer or the like in the exposed state, the portion where the cap 9 is present has a different sound and response. That is, since styrofoam is very soft and has a lower density than concrete, the portion of the styrofoam cap 9 sounds and feels as if a cavity exists. Therefore, the portion where the cap 9 exists can be easily found. Then, the concrete in that portion is scraped off to break and remove the cap 9 (FIG. 6).

Thereafter, the both ends of the sleeve 5 are
The crusher 15 is inserted as shown in FIG. This crusher 15
As shown in FIGS. 9 to 11, a cylindrical outer shell 17 is divided into two parts by a plane passing through an axis. Further, a diamond-shaped space 19 is formed between the two outer shells 17,
The outer shell 17 has a vertically divided cylindrical shape. This diamond-shaped space 19
Wedges 21 are slidably provided at both ends of the. A rubber tube 23 as a bag is accommodated between the two wedges 21 so that it can be expanded and contracted by hydraulic pressure. When the rubber tube 23 expands due to the hydraulic pressure, the wedge 21 is pushed, slides along the inner surface of the rhombus, and pushes the two outer shells 17 outward. This pushing force can split the hole formed in the concrete. It is desirable to cover the crusher 15 with a synthetic resin bag. By covering the bag, it is possible to easily remove the crusher 15 from the hole after the splitting is completed.

The direction of the vertical division of the outer shell 17, that is, FIG.
Alternatively, the horizontal direction in FIG. 11 is matched with the direction in which the underground continuous wall is to be split. In this way, all the crushers 15 are arranged in a state where both directions are matched (FIG. 12).

The crusher 15 is inserted into the sleeve 5 and a hydraulic pressure is applied to split the sleeve 5 and the hole formed by the sleeve. By this splitting, the head 13 of the underground continuous wall is split into a plurality of blocks. If the plurality of divided blocks are pulled out, the main bar 8 and the concrete 11 are not fixed by the action of the edging sleeve 10 and can be easily pulled out. In this way, the head 13 of the underground continuous wall can be cut off and removed (FIG. 8).

As described above, since the outer shell having a vertically split shape is pushed apart and split by hydraulic pressure, even if the sleeves are installed in parallel, the upper part of FIG. As shown by a dotted hatch portion shown in a sectional view parallel to the longitudinal direction of the crushing device 15, a deep position can be reliably crushed. The splitting can be completed by matching the direction of the vertical split of the outer shell 17 of the crusher 15 with the direction in which the splitting is to be performed. That is, as shown in the lower diagram of FIG. 12 (a cross-sectional view orthogonal to the longitudinal direction of the crushing device 15),
By the function of (1), the generated cracks are not substantially in all directions as in the prior art, but in the direction of the vertical division of the outer shell 17 (the horizontal direction in the lower diagram of FIG. 12) (the dotted line portion in the lower diagram of FIG. 12) . Therefore, the energy given by the hydraulic pressure does not cause a crack to be generated in another direction different from the direction to be split and is not wasted, so that it is possible to use one direction, that is, the outer shell 1.
7 is used only in the direction of the vertical split.

As a result, a sufficiently deep crack is generated only in the vertical split direction, that is, in the direction in which the split is to be performed. Therefore, splitting is performed efficiently. And by arranging all the crushers 15 in such a manner that both directions coincide, it is possible to easily cut off the head of the underground continuous wall.

In the above embodiment, the crusher 15 has the wedge 21 provided between the two outer shells 17, but in other embodiments, the crusher 15 does not have the wedge 21. It is also possible to use the machine 15.

[0022]

As described above, according to the method for sharpening the head of a continuous underground wall of the present invention, the inflation of a bag housed in a vertically divided cylindrical shape in which a crushing instrument to be used is used. Therefore, splitting can be performed uniformly over the entire longitudinal direction, and crushing can be performed efficiently.
In particular, it is installed at both ends of the internal space of a vertically divided cylindrical outer shell.
Push out the outer shell with a slidable wedge
By doing so, the uniformity of splitting can be improved.
Therefore, the crushing efficiency can be further improved. Also,
By matching the direction of the vertical split of the outer shell of the crusher with the direction to split the underground continuous wall, it is possible to generate a sufficiently deep crack in the direction to split, and to perform efficient splitting, Therefore, it is possible to easily cut off the head of the underground continuous wall.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a side view of FIG. 1;

FIG. 4 is a view showing a state where concrete is cast in FIG. 3;

FIG. 5 is a view showing a state where the head of the concrete structure is exposed in FIG. 4;

FIG. 6 is a diagram showing a state in which a cap is searched for and removed in FIG. 5;

FIG. 7 is a view showing a state in which a crusher is inserted into the sleeve opened according to FIG. 6;

FIG. 8 is a diagram showing a state in which the head of a concrete structure is shaved off by a crusher.

FIG. 9 is an enlarged view showing the crusher of FIG.

FIG. 10 is a sectional view of a main part of FIG. 9;

FIG. 11 is a diagram showing the operation of FIG. 10;

FIG. 12 is a view for explaining the operation of the crusher arranged as in FIG. 7;

FIG. 13 is a view showing the operation of a conventional crusher.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drilling hole 3 Rebar basket 5 Sleeve 7 Simple tie-down band (Nylon insulok) 8 Main bar 9 Styrofoam cap 10 Edge cutting sleeve 11 Concrete 13 Head 15 Crusher 17 Outer shell 21 Wedge 23 Rubber tube

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masami Ito 2-3-3 Kandaji-cho, Chiyoda-ku, Tokyo Obayashi Corporation Tokyo Head Office (72) Inventor Ryuji Itagaki 2-3-3 Kandaji-cho, Chiyoda-ku, Tokyo Stock Obayashi Corporation Tokyo Head Office (56) References JP-A-61-176716 (JP, A) JP-A-3-107017 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02D 5 / 34 E02D 5/18-5/20

Claims (2)

(57) [Claims] When a concrete reinforcing bar is placed in an underground excavation hole and concrete is cast to construct an underground continuous wall, a sleeve is attached to a reinforcing steel bar before concrete placing, concrete is cast and cured, and then the basement is cured. Exposure of the head of the continuous wall, splitting by inserting a crusher into the sleeve of the head, in the method of sharpening the head of the underground continuous wall to sharpen the head,
The crushing machine is for storing a bag inside a vertically divided cylindrical outer shell, expanding the bag by hydraulic pressure, and expanding the outer shell.The direction of the vertically dividing should be split. A method for sharpening the head of a continuous underground wall, comprising arranging a crusher in a direction corresponding to the direction. 2. A concrete reinforced basket is placed in an underground excavation hole.
When constructing an underground continuous wall by casting
Attach a sleeve to the reinforcing steel before casting
After casting and curing, the head of the underground continuous wall is exposed,
Insert a crusher into the sleeve of the head to split it,
In the method of sharpening the head of a continuous underground wall,
The crushing machine puts a bag inside a vertically divided cylindrical outer shell.
The bag is stored, the bag is expanded by hydraulic pressure, and the vertically divided circle is stored.
Slidable provided at both ends of the internal space of the cylindrical outer shell
Push out the vertically divided cylindrical outer shell with a wedge
Wherein the direction of the vertical split is the same as the direction of the split.
Underground continuous wall characterized by arranging crushing machines
How to sharpen the head.