JPH0726385B2 - Construction method for underground wall - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of constructing a continuous underground wall that constitutes a retaining soil, a water stop wall, a substructure, and the like.

[Conventional technology]

Generally, the underground continuous wall is constructed by drilling a long hole, inserting a reinforcing bar cage into it, and placing it into concrete to divide it into individual panels.The trailing panel is sequentially connected to the preceding panel. It is something that will be constructed.

Then, it is necessary to wrap the reinforcing bars of the adjacent panels together so that the connecting portion between the panels maintains a sufficient connection strength.

FIG. 5 shows an example thereof, in which 1 is the preceding panel,
Reference numeral 2 is a reinforcing bar cage inside thereof, and a horizontal bar 4 for wrapping is projected from the end of the preceding panel 1, while the horizontal bars 5, 5 at the rear end of the reinforcing bar basket 4 for the trailing panel have a mutual width of their front ends. It is formed to be narrower than the width between the horizontal stripes 3 of the preceding panel.

In this way, the lap length is secured by inserting the horizontal bars 5,5 between the horizontal bars 3,3, but when considering the ease of erection of the reinforcing bar cage 4 preassembled on the ground, the horizontal bars 3 There was a certain distance a between the and the horizontal line 5.

[Problems to be Solved by the Invention]

In such a conventional underground continuous wall, as described above, since the lateral streaks 3 and 5 of the joint portion are separated by the amount of a, a split crack that sew between them occurs as shown in FIG. 6, The joint may be brittlely broken.

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.

On the other hand, as shown in JP-A-57-21621, the longitudinal reinforcing bars of the reinforcing bars of the reinforcing bar cage to be built are pivotally attached to the transverse reinforcing bars, and the stirrup reinforcing bars are previously attached to the longitudinal reinforcing bars. It is proposed that the stirrup rebar is hung by rotating the longitudinal rebar after welding and installing.

However, in such a method, the structure in which the longitudinal reinforcing bars are pivotally attached in the wrap portion is troublesome, and the connection between the longitudinal reinforcing bars and the transverse reinforcing bars is weakened, and a decrease in strength cannot be avoided.

The object of the present invention is to solve the inconvenience of the conventional example, to facilitate the installation work of the trailing panel, and to obtain a strong joint, and to improve the proof strength and toughness of the joint portion. To provide a wall construction method.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention provides a method of constructing a continuous underground wall in which a horizontal bar projecting from an end of a preceding panel is connected to a horizontal bar of a reinforcing bar basket for a trailing panel by wrapping, and a horizontal bar of the reinforcing bar basket for the preceding panel is connected. The longitudinal streaks that arrive at the rear panel are arranged on the outside, and the longitudinal streaks that reach the lateral bars of the rear panel reinforcing bar cage are arranged on the inside, and the ends of the horizontal bars of the rear panel reinforcing bar cage are constrained by the wire steel material. The width is narrower so that it can be repositioned, and it is restored to the original width even if the wire steel is removed after it has been installed between the horizontal stripes at the end of the preceding panel, and the horizontal stripes on the leading panel side and the trailing panel side are vertically aligned. The idea is to superimpose them on the same plane.

[Action]

According to the present invention, after the rebar cage for the trailing panel is built,
When the constrained state of the wire steel material is released from the ground, the end lateral bar that was narrow until then is restored by the elasticity of the reinforcing bar and the lateral bars on the leading panel side and the trailing panel side overlap in the same plane in the vertical direction. So there is no gap between them.

Moreover, since the overlapping horizontal streaks are reinforced by the vertical streaks in a lattice pattern, the strength of the joint portion becomes high.

Further, since the horizontal stripes are overlapped with each other, the thickness can be reduced and the accuracy of the width of the panel can be improved. Moreover, since the gap between the horizontal streaks or the vertical streaks becomes dense, the strength of the joint joint is also increased.

Further, since the horizontal stripes of the leading panel and the trailing panel overlap each other in the upper direction, it is possible to prevent the trailing panel from being vertically displaced such as being lifted.

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 to 3 are plan views showing respective steps of the method for constructing a continuous underground wall of the present invention, in which the same components as those in FIGS. 5 and 6 showing the conventional example are designated by the same reference numerals. It was done.

First, as shown in FIG. 1, the preceding panel 1 has been completed, and the rear panel side is formed so that the combined lattice body of the horizontal bars 3 and the vertical bars 7 extends from the end of the reinforcing bar cage 2 in two parallel rows. Overhangs.

Next, as shown in FIG. 2, a reinforcing bar cage 4 for the trailing panel after the drilling is built, and the reinforcing bar cage 4 is a wire steel material 6 such as a number wire or a small diameter reinforcing bar as a restraining member in advance on the ground. Bind the five so that they are narrow. There are various conceivable ways of tying, but it is desirable to sequentially hang them on the horizontal streaks 5 in the vertical direction so that they can be easily released by pulling one afterward like a lacing of a lace. In the figure, 12 is a purse stop, which is stretched between the lateral streaks 5 and 5 as necessary.

In this way, the reinforcing bar cage 4 having the ends squeezed with the wire steel material 6 is erected to a predetermined depth so that the squeezed portion can be inserted between the horizontal bars 3, 3 of the preceding panel 1.

And when the construction is completed, the wire steel material 6 is unwound,
Alternatively, if it is cut in water by a suitable method (the inside of the hole is filled with bentonite solution, etc.), the horizontal bar 5 is elastically restored and overlaps with the horizontal bar 3 in the same plane in the vertical direction.

The vertical stripe 7 that reaches the horizontal stripe 3 is outward, and the vertical stripe 8 that reaches the horizontal stripe 5 is
Are arranged inside, and as shown in FIG. 4, these vertical stripes 7 and 8 are located outside the overlapping portion of the horizontal stripes 3 and 5, and do not interfere.

〔The invention's effect〕

As described above, the construction method of the underground continuous wall of the present invention is a construction method of the underground continuous wall in which the horizontal bar protruding from the end of the preceding panel is connected to the horizontal bar of the rebar cage end for the trailing panel by wrapping, Since the horizontal stripes on the panel side and the trailing panel side overlap each other on the same plane in the vertical direction, there is no gap between them, the density of this joint is increased, and the yield strength and toughness of this joint are improved. Is something that can be done.

Moreover, since the overlapping horizontal streaks are reinforced by the vertical streaks in a lattice pattern, the strength of the joint portion becomes high.

[Brief description of drawings]

1 to 3 are plan views showing each step in the first embodiment of the method for constructing a continuous underground wall of the present invention, and FIG. 4 is an AA line in FIG.
FIG. 5 is a plan view showing a conventional example, and FIG. 6 is a plan view showing a conventional crack generation state. 1 ... Leading panel 2 ... Reinforcing bar cage 3 ... Horizontal reinforcing bar 4 ... Reinforcing bar basket for trailing panel 5 ... Horizontal reinforcing bar, 6 ... Wire steel material 7,8 ... Vertical reinforcing bar

Claims (1)

[Claims] 1. A method for constructing an underground continuous wall in which a horizontal bar projecting from the end of a preceding panel is connected to a horizontal bar of a reinforcing bar basket for a trailing panel by wrapping the horizontal bar, and the vertical bar that reaches the horizontal bar of the reinforcing bar basket for the preceding panel is It is possible to forcibly return to the outside by arranging the vertical bar that reaches the horizontal bar of the reinforcing rod cage for the trailing panel inside, and binding the tip of the horizontal bar of the reinforcing rod cage for the trailing panel with wire steel. The width is made narrow, and after it is installed between the horizontal stripes at the end of the preceding panel, the wire steel material is removed to restore the original width, and the horizontal stripes on the leading panel side and the trailing panel side overlap in the same plane in the vertical direction. A method of constructing a continuous underground wall that is characterized by: