JPH0360973B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of constructing underground walls constituting earth retaining walls, water-stop walls, foundation structures, and the like.

[Conventional technology]

The construction method for an underground continuous wall is generally to drill a long hole,
Each panel is constructed by pushing a reinforcing cage into it and pouring concrete, and the trailing panels are successively connected to the leading panels.

In order to maintain sufficient connection strength at the connection between each panel, it is necessary to wrap the reinforcing bars of adjacent panels together.

Figure 7 shows an example. In the figure, 1 is the preceding panel, 2 is the reinforcing cage inside, and the preceding panel
A horizontal reinforcement 3 for wrapping is provided protruding from the end of the reinforcing bar cage 4 for the trailing panel, and the width of the mutual width of the tip of the horizontal reinforcement 5, 5 at the rear end of the reinforcing bar basket 4 for the trailing panel is larger than the width between the horizontal reinforcement 3, 3 of the preceding panel. It is also narrowly formed.

In this way, the lap length is secured by inserting the horizontal reinforcements 5, 5 between the horizontal reinforcements 3, 3, but when considering the ease of erection of the reinforcing bar cage 4, which is pre-assembled on the ground, the horizontal reinforcement 3 is inserted between the horizontal reinforcements 3, 3. A certain distance a existed between the horizontal strip 5 and the horizontal strip 5.

[Problem that the invention seeks to solve]

In such a conventional underground continuous wall, since the horizontal reinforcements 3 and 5 at the joint are separated by a distance as described above, splitting cracks occur between them as shown in Figure 8. There is a risk of the joint being fragile.

This failure occurs after the transverse bar yields when the reinforcing bar ratio is relatively small, and before the transverse bar yields when the reinforcing bar ratio is relatively large.

In contrast, as shown in Japanese Patent Application Laid-Open No. 57-21621, the vertical reinforcing bars of the lap portion of the reinforcing bar cage to be erected are pivoted to the horizontal reinforcing bars, and stirrup reinforcing bars are welded to the vertical reinforcing bars in advance. It has been proposed that the stirrup reinforcing bars be spanned by rotating the longitudinal reinforcing bars after erection.

However, in this method, the structure for pivoting the longitudinal reinforcing bars at the lap portion is complicated, and the connection between the longitudinal reinforcing bars and the horizontal reinforcing bars becomes weak, resulting in a decrease in strength.

The purpose of the present invention is to eliminate the disadvantages of the conventional example,
An object of the present invention is to provide a construction method for an underground continuous wall that can easily improve the strength and toughness of a joint part.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention provides a construction method for an underground continuous wall in which the horizontal reinforcements at the end of the reinforcing bar for the trailing panel are wrapped and connected to the horizontal reinforcements protruding from the edge of the preceding panel. The gist of this method is to insert reinforcing members projecting vertically at appropriate intervals on both sides of a horizontal arm whose tip is bent downward from the shaft, and to span and lock the horizontal arm across the transverse striations.

[Effect]

According to the present invention, if the reinforcing material is inserted from above with its horizontal arm approximately parallel to the transverse reinforcement, and when lowered to a predetermined position, the upper end of the shaft is rotated on the ground, and the horizontal arm is inserted between the horizontal reinforcement in the vertical direction. is inserted.

Then, if you lower it a little further, the bent end of the horizontal arm will lock onto the outside of both the horizontal strips on the leading and trailing panels, and the horizontal strips will be connected to each other via this horizontal arm and the central axis, resulting in a wrap. The gaps between the transverse reinforcements are closed with reinforcing material.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

First, the reinforcing material 8 used in the construction method of the present invention will be explained first. As shown in FIG. 10 is attached by welding or the like. A plurality of horizontal arms 10 are provided at appropriate intervals in the vertical direction of the central axis 9, and the interval is made to match the vertical interval of the horizontal bars 3 and 5, and the horizontal arms 10 protrude left and right around the axis 9.
The width of the hooks 10a at both ends is the width of the horizontal stripes 3 and 5.
It was set the same as the gap a. In addition, this reinforcing material 8
Deformed reinforcing bars, steel materials, etc. are suitable as the material for composing.

Figures 1 to 4 are plan views showing each step of the construction method of an underground continuous wall of the present invention, and Figure 7 shows the conventional example.
Components that are the same as those in FIG. 1 and FIG. 8 are given the same reference numerals.

First, as shown in Fig. 1, the preceding panel 1 has been completed, and from its end, the following panel has a lattice of combinations of horizontal reinforcements 3 and vertical reinforcements 7 arranged in two parallel rows to form an extension of the reinforcing bar cage 2. protrudes to the side.

Next, as shown in FIG. 2, the reinforcing bar cage 4 for the trailing panel is erected after drilling, but as in the conventional example, the width of the horizontal bars 5, 5 at the rear end is set to the width between the horizontal bars 3, 3 of the preceding panel. It is formed narrower than the width.

Then, as shown in FIG. 3, the reinforcing member 8 is inserted from the ground into the gap a between the wrapping transverse reinforcements 3 and 5 so that its horizontal arms 10 are approximately parallel to each other, and
Lower it to the specified depth. In this case, the horizontal arm 10 is located at the same height as the midpoint between the top and bottom of the transverse bars 3 and 5.

If the upper end of the central shaft 9 is rotated on the ground in this state, the arm 10 will also pivot as shown in FIGS. 5 and 6, and its tip will intersect the horizontal stripes 3 and 5 in the vertical direction. Furthermore, when the center shaft 9 is lowered a little, the arm 10 is also lowered and the hooks 10a at both ends are
This horizontal arm 1 is locked from the top to the outside.
0, the transverse bars 3 and 5 are connected.

As a result, the gap a between the horizontal reinforcements 3 and 5 is closed with the reinforcing material 8, and then concrete for the trailing panel is poured.

It should be noted that if such reinforcement material 8 is placed, there is a concern that the concrete will not flow well, but it is also possible to pour the concrete first and then insert and set the reinforcement material 8 before it hardens. .

〔Effect of the invention〕

As described above, the construction method for an underground continuous wall of the present invention is such that the horizontal reinforcement at the end of the reinforcing bar for the trailing panel is wrapped and connected to the horizontal reinforcement protruding from the end of the preceding panel. Since the reinforcing material is provided in the gap between the horizontal reinforcements, the strength and toughness of the joint can be improved.

Moreover, this set of reinforcing materials can be safely and easily constructed from the ground without changing the structure of the conventional reinforcing bar cage.

[Brief explanation of drawings]

Figures 1 to 4 are plan views showing each step in the first embodiment of the underground wall construction method of the present invention, Figure 5 is a front view of the reinforcing material, and Figure 6 is the same as in Figure 4. FIG. 7 is a plan view showing a conventional example, and FIG. 8 is a plan view showing a state in which cracks occur. 1... Leading panel, 2... Rebar cage, 3... Horizontal reinforcement, 4... Reinforcement cage for trailing panel, 5... Horizontal reinforcement,
6, 7... Vertical reinforcement, 8... Reinforcement material, 9... Central axis,
10...Horizontal arm, 10a...Hook.

Claims (1)

[Claims] 1. In the construction method of an underground continuous wall in which the horizontal reinforcement at the end of the reinforcing bar for the trailing panel is wrapped and connected to the horizontal reinforcement protruding from the edge of the leading panel, the tip is bent downward from the central axis between the wrapped horizontal reinforcements. A method of constructing an underground continuous wall, characterized by inserting reinforcing members protruding from horizontal arms at appropriate intervals in the vertical direction on both sides, and suspending and locking the horizontal arms across horizontal reinforcements.