JPH05321248A - Method for removing head part of underground contrinuous wall - Google Patents

Abstract

PURPOSE:To enhance the effectiveness in works to burst the head part of an underground continuous wall to remove it, by inserting a crusher in a sleeve fitted at the head, inflating a sack accommodated in a vertically split shell in cylindrical form with a liquid pressure, and thereby expanding the shell wherein the vertically splitting direction is put identical to the bursting direction. CONSTITUTION:A shell 17 in cylindrical form is two split about a plane passing the axis, and inside thereof a sack such as a rubber tube is accommodated, and a crusher 15 is instaled which has possibility of expanding and contracting with the liquid pressure. This crusher 15 is inserted in a sleeve 5 in the condition that the vertically splitting direction of the shell 17 is put identical to the direction in which the head part of an underground continuous wall is to be bursted as the object of the present invention. Liquid pressure is applied to the crusher 15, and the sleeve 5 and a hole generated thereby are bursted to split the wall head 13 into a plurality of blocks. Thereby the burst is done uniformly over the whole area in the longitudinal direction, and the head part can easily be shaved off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for scraping off the head of an underground continuous wall.

[0002]

2. Description of the Related Art An underground continuous wall constructed in the ground is constructed by placing a reinforced cage in an excavation hole in the ground and placing concrete. The drill hole is filled with a bentonite solution for preventing collapse of the inner wall of the drill hole. Since the concrete is poured in this filled state, the bentonite solution is mixed in the head of the underground continuous wall after the concrete is cured and hardened, and the strength and the like are insufficient. For this reason, this head must be scraped off.

This scraping is also necessary to expose the reinforcing bars from the concrete for connecting the underground continuous wall to other concrete structures.

In this method of scraping, first, a sleeve is attached to a reinforcing bar before concrete is placed, concrete is placed and cured, and then the head is exposed. Then, a crusher is inserted into the sleeve provided on the head to split the sleeve (JP-A-62-90443, JP-A-63-308113).

This crusher is a wedge called a wedge whose tip is thin.

[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 thin tip is driven into the sleeve 5, the above figure (wedge 2
As shown in the cross-sectional view parallel to the longitudinal direction of No. 1), no crushing force was applied to the tip portion, and a portion that did not split occurred in the deep portion of the concrete. Further, as shown in the figure below (cross-sectional view orthogonal to the longitudinal direction of the wedge 2), the crack (dotted line portion in the figure) enters substantially all directions of the periphery, and the energy at the time of driving is dispersed. Therefore, a sufficiently deep crack is not formed in the direction to be split, and efficient splitting cannot be performed.

The present invention has been made in order to solve the above-mentioned problems, and the head scooping of an underground continuous wall capable of efficiently splitting a deep crack in the splitting direction. The purpose is to provide a method.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a concrete pouring method when an underground continuous wall is constructed by placing a rebar cage in an underground excavation hole and pouring concrete. A sleeve is attached to the front reinforcing bar, and after concrete is set and cured, the head of the underground continuous wall is exposed, and a crusher is inserted into the sleeve of this head to split it, and the head is scraped off underground. In the method for picking up the head of a continuous wall, the crusher stores a bag inside a vertically split cylindrical outer shell, and expands the outer shell by expanding the outer shell by hydraulic pressure. It is characterized in that the crusher is arranged such that the direction of the vertical division coincides with the direction to be split.

[0009]

[Function] The deep part of the underground continuous wall can be efficiently split. Also, if the direction of the vertical split of the outer shell is made to match the direction in which it should be split, when the bag expands by hydraulic pressure and pushes the outer shell apart, it will be sufficient along the vertical split direction of the outer shell. Deep cracks can be obtained, which can prevent unnecessary cracks in the other direction from dissipating energy.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An 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 FIGS. 1 to 3, the rebar cage 3 is placed in the excavation hole 1 excavated in the ground. A sleeve 5 for inserting a crusher is attached to the rebar cage 3 in the horizontal direction and the vertical direction. A large number of these sleeves 5 are attached, and the aim is to split the head of the underground continuous wall, which is a concrete structure, so that it can be scraped off into a block of a predetermined size.

The sleeve 5 has a cylindrical shape made of, for example, vinyl chloride, and is squeezed with a simple fastening band 7 on the main bar of the rebar cage 3 or the like. This simple lashing band 7 is made of nylon insulock so that the squeezing force is not too strong. Both ends of the sleeve 5 are drilled holes 1
Located near the wall of the hole. As a result, it will be located near the surface of the concrete after it has been poured. Both ends are covered with styrofoam caps 9. The cap 9 is in the shape of a short cylinder having a larger cross section than that of the sleeve 5.

An edge cutting sleeve 10 is put on the main bar 8 of the reinforcing bar car 3. The edging sleeve 10 is present only on the part of the head that is scraped off of the underground continuous wall.

As described above, the rebar cage 3 having the sleeve 5 covered with the cap 9 is placed in the excavation hole 1 (see FIGS. 1 to 1).
3), concrete 11 is poured (FIG. 4). The excavated hole 1 is generally filled with a bentonite solution so that the hole wall does not collapse, and the cast concrete 11 is replaced with the bentonite solution. The bentonite solution, which is light with respect to the concrete, moves above the drill hole 1. Then, a part of the bentonite solution mixes with the concrete 11 above this. Due to this mixing, the strength of the concrete 11 becomes insufficient. Then, after the concrete 11 is cured and hardened, the head 13 of the underground continuous wall is excavated and exposed (FIG. 5).

When the surface of the concrete 11 is tapped with a hammer or the like in this exposed state, the part where the cap 9 is present has a different sound and texture. That is, since styrofoam is much softer and has a lower density than concrete, the portion of the cap 9 made of styrofoam gives a sound and a feeling as if there is a cavity. Therefore, the portion where the cap 9 is present can be easily found. Then, the concrete of the part is scraped off and the cap 9 is broken and removed (FIG. 6).

Then, as shown in FIG.
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 by a surface passing through the axis. Further, a diamond-shaped space 19 is formed between the two outer shells 17,
The outer shell 17 has a vertically split 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 housed between the two wedges 21 so that it can be expanded and contracted by liquid pressure. When the rubber tube 23 is expanded by hydraulic pressure, the wedge 21 is pressed and slides along the inner surface of the rhombus to push the two outer shells 17 outwardly. This pushing force can split the holes formed in the concrete. It is desirable to cover the crusher 15 with a synthetic resin bag. By covering this bag, the crusher 15 can be easily removed from the hole after the splitting is completed.

The longitudinal direction of the outer shell 17, that is, FIG.
Alternatively, the left-right direction of FIG. 11 is made to coincide 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 hydraulic pressure is applied to split the sleeve 5 and the hole formed by the sleeve. By this splitting, the head portion 13 of the underground continuous wall is split into a plurality of blocks. When 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 therefore can be easily pulled out. In this way, the head portion 13 of the underground continuous wall can be scraped off and removed (FIG. 8).

As described above, since the outer shell divided into two parts in the vertical direction is expanded and split by hydraulic pressure, even when the sleeves are installed in parallel, the upper diagram of FIG. Like a dotted hatch portion shown in a cross-sectional view (parallel to the longitudinal direction of the crushing device 15), a deep position can be reliably crushed. Further, 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 to split. That is, as shown in the lower diagram of FIG. 12 (cross-sectional view orthogonal to the longitudinal direction of the crushing device 15), the crusher 15
Due to the function of, the crack generated is not in the general omnidirectional direction as in the conventional case but in the direction of vertical division of the outer shell 17 (left and right direction in the lower diagram of FIG. 12) (dotted line portion in the lower diagram of FIG. 12) .. Therefore, the energy given by the hydraulic pressure is not wasted by causing a crack in another direction different from the direction in which it should be split, and is used in one direction, that is, the outer shell 1.
It is used only in the direction of 7 vertical divisions.

As a result, a sufficiently deep crack is generated only in the longitudinal splitting direction, that is, in the splitting direction. Therefore, the splitting is performed efficiently. By arranging all the crushers 15 so that the two directions coincide with each other, it is possible to easily scrape 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 the other embodiments, the crusher does not have the wedge 21. It is also possible to use the machine 15.

[0022]

As described above, according to the method for removing head from a continuous underground wall according to the present invention, the crushing device to be used utilizes the expansion of the bag housed inside the vertically divided cylindrical shape. Therefore, it can be split evenly over the entire longitudinal direction, and efficient crushing can be performed.
Also, by matching the direction of vertical splitting of the outer shell of the crusher with the direction in which the underground continuous wall should be split, a sufficiently deep crack can be generated in this splitting direction, resulting in efficient splitting. Therefore, the head of the continuous underground wall can be easily removed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a side view of FIG.

FIG. 4 is a view showing a state where concrete is poured in FIG.

FIG. 5 is a diagram showing a state in which the head of the concrete structure is exposed in FIG.

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

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

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

FIG. 9 is an enlarged view showing the crusher of FIG. 7.

10 is a cross-sectional view of the main parts of FIG.

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

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

FIG. 13 is a diagram showing an operation of a conventional crusher.

[Explanation of symbols]

 1 Drilling Hole 3 Reinforcing Bar Basket 5 Sleeve 7 Simple Secure 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

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasue Tanabe 2-11-1, Shibadaimon, Minato-ku, Tokyo Nippon Mining Machinery Co., Ltd. (72) Inventor Masami Ito 2-3 Kandaji-cho, Chiyoda-ku, Tokyo Shares Ceremony Company Obayashi Tokyo Main Office (72) Inventor Ryuji Itagaki 2-3 Kandajimachi, Chiyoda-ku, Tokyo Stock Company Obayashi Tokyo Main Office

Claims (1)

[Claims] 1. When constructing an underground continuous wall by placing a steel cage in an underground excavation hole and placing concrete, a sleeve is attached to the steel rod before placing concrete, and concrete is placed and cured before underground. In exposing the head of the continuous wall, insert a crusher into the sleeve of this head to split, head scraping method of the underground continuous wall to scrape off the head,
The crusher is for accommodating a bag body inside a vertically split cylindrical outer shell and expanding the outer shell by expanding the bag body by hydraulic pressure, and the direction of the vertical split should be split. A method for scraping off the head of an underground continuous wall, which is characterized by placing a crusher in line with the direction.