JPH07138943A - Joint structure of underground wall - Google Patents

Abstract

(57) [Summary] [Purpose] A horizontally long trench is formed in the ground, a reinforced basket is inserted into the trench, and concrete is placed in the trench to form a reinforced concrete panel in the ground. , In a continuous underground wall where the concrete panels are sequentially connected as unit elements, if the reinforcing bar joint of the trailing element is arranged in the reinforced joint of the preceding element, the covering concrete side It is possible to easily prevent the reinforcing bar joint in 2 from popping and cracking, and the proof stress of the joint portion lowering. [Structure] A post-construction anchor 12 is installed in the concrete near the reinforcing bar joint 5 of the reinforcing bar basket 4 of the preceding element 1 on the cover concrete side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground joint wall joint structure.

[0002]

2. Description of the Related Art As is well known, a continuous underground wall constructed as a continuous panel made of reinforced concrete has a laterally long excavation groove formed in the ground, a reinforcing steel basket is inserted into the excavation groove, and then concrete is excavated. A preceding panel made of reinforced concrete is formed in the groove by placing it in the groove, and this individual panel made of concrete is used as a unit element and sequentially connected.

FIG. 3 shows a case in which the lap joint method is adopted in the construction of such an underground continuous wall, and the preceding element 1 has a reinforcing bar basket in which a partition plate 3 as an iron plate form is incorporated at the rear end. 4, the horizontal strip 5a and the vertical strip 5b from the partition plate 3
The rebar joint 5 is projected. Predecessor element 1
Concrete 6 to be cast on the side is stopped by this partition plate 3.

The trailing element 2 is provided with a reinforcing bar basket 9 whose end portion is a reinforcing bar joint 8 composed of a horizontal bar 8a and a vertical bar 8b. The horizontal bar 8a of the reinforcing bar joint 8 is a reinforcing bar joint on the side of the preceding element 1. The width is narrow so as to enter the space between the horizontal stripes 5a of No. 5.

After the concrete 6 of the preceding element 1 is poured, the reinforcing bar basket 9 of the trailing element 2 is arranged in the excavation groove 10, and although not shown, the concrete of the trailing element 2 is poured. The lapped horizontal rebar joint 5 and the horizontal rebar joint 8 are joined by a lap joint.

[0006]

According to the conventional joining method shown in FIG. 3, the reinforcing bar joint 5 and the reinforcing bar joint 8 are horizontally separated from each other for the purpose of connecting the reinforcing bar baskets to each other so that they cross the lap joint bars. It cannot be reinforced like this. As a result, when an out-of-plane bending stress β is applied, as shown by α in FIG. 3, split concrete cracks across the lap joint portion by the horizontal ribs 5a and 8a instantly occur in the concrete on the trailing element 2 side, and the reinforcing bar joint 5
May be popped off and the yield strength may be reduced.

The object of the present invention is to eliminate the disadvantages of the prior art and to prevent split fracture when the reinforcing bar joint of the trailing element of the reinforcing bar basket is arranged in the reinforcing bar joint of the preceding element with the lap joint. It is to provide a joint structure for an underground wall.

[0008]

In order to achieve the above-mentioned object, the present invention forms a laterally long excavation groove in the ground, inserts a rebar cage into the excavation groove, and places concrete in the excavation groove. A reinforced concrete panel is constructed in the ground, and this concrete panel is sequentially connected as a unit element.Underground continuous wall, the reinforced joint of the reinforced basket of the preceding element and the reinforced joint of the reinforced basket of the following element are lap joints. In the joint structure of the underground wall to be joined by, the post-construction anchor is installed in the concrete near the reinforcing bar joint of the reinforcing bar basket of the preceding element on the cover concrete side.

[0009]

According to the present invention, even if the cover concrete including the horizontal streaks on the leading element side is about to be separated due to the out-of-plane bending, the post-installed anchor suppresses the separation.

As a result, the leading element side horizontal muscle is in a state capable of transmitting the tensile force to the trailing element side horizontal muscle, so that the bending resistance does not decrease.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is the first of the joint structure of the underground wall of the present invention.
FIG. 2 is a plan view showing an embodiment, and FIG. 2 is a side view showing the same, in which the same components as those in FIG. 3 showing the conventional example are designated by the same reference numerals.

In the figure, 5 is a reinforcing bar basket 4 on the side of the preceding element 1.
Is a horizontal reinforcing bar 5a and a vertical reinforcing bar 5b, and 8 is a reinforcing bar coupling at the tip of the reinforcing bar basket 9 on the trailing element 2 side,
It consists of horizontal stripes 8a and vertical stripes 8b.

The reinforced steel basket 4 is hung and the concrete 6
After casting to form the panel of the preceding element 1,
Arrange the rebar cage 9 of the trailing element 2 in the excavation groove 10,
The point that concrete 11 is cast on the trailing element 2 side to form a trailing panel to form a continuous underground wall is the same as the conventional example shown in FIG.

After the underground continuous wall is completed, the ground of the building side (a) is excavated (root cutting) to expose the surface of the underground continuous wall.

According to the present invention, on the exposed surface, that is, on the side subjected to pulling by the out-of-plane bending, near the tip of the reinforcing bar joint 5 on the side of the preceding element 1, the horizontal bar 5a of the reinforcing bar joint 5 is provided.
The post-installed anchor 12 was installed so as to straddle the and the horizontal bar 8a of the reinforcing bar joint 8 on the trailing element 2 side that is lap-joined thereto.

At this time, the post-installed anchors 12 are also positioned between the vertical bars 5b of the reinforcing bar joint 5 and between the vertical bars 8b of the reinforcing bar joint 8, and are further arranged vertically at appropriate intervals. In the figure
12a is a fixing plate at the end of the post-installed anchor 12.

In the figure, the post-installed anchor 12 is a bond anchor (resin anchor) which is made by drilling a hole in a concrete wall and fixing a reinforcing bar, which is a tension material to be inserted into the hole, with a resin for injecting it around the hole. It is also conceivable to use other post-installed anchors such as metal expansion anchors. Also, bolts or screws may be used instead of the reinforcing bars.

In this way, since the post-installed anchor 12 is provided, the underground wall undergoes out-of-plane bending, and even if the cover concrete containing the horizontal streaks 5a on the side of the preceding element 1 is about to separate, the separation can be suppressed. As a result, the horizontal line 5a on the side of the preceding element panel 1 can transmit the tensile force to the horizontal line 8a on the side of the following element 2.

[0019]

As described above, the joint structure of the underground continuous wall of the present invention, when the reinforcing bar joint of the trailing element is arranged in the reinforced joint of the reinforcing bar basket of the preceding element by a lap joint, It is possible to easily prevent the reinforced joint on the cover concrete side from popping and cracking, which lowers the yield strength of the joint.

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view showing a first embodiment of a joint structure for an underground continuous wall according to the present invention.

FIG. 2 is a side view showing a first embodiment of a joint structure for an underground continuous wall according to the present invention.

FIG. 3 is a cross-sectional plan view showing a conventional example.

[Explanation of symbols]

 1 ... Leading element 2 ... Trailing element 3 ... Partition plate 4 ... Reinforcing bar basket 5 ... Reinforcing bar joint 5a ... Horizontal bar 5b ... Vertical bar 6 ... Concrete 8 ... Reinforcing bar joint 8a ... Horizontal bar 8b ... Vertical bar 9 ... Rebar bar 10 ... Excavation groove 11… Concrete 12… Post-installed anchor 12a… Fixing plate

Claims (1)

[Claims] 1. A horizontally elongated excavation groove is formed in the ground, a reinforced basket is inserted into the excavation groove, and concrete is placed in the excavation groove to form a reinforced concrete panel in the ground. In a continuous underground wall in which panels of are connected sequentially as unit elements, in a continuous wall joint structure in which the reinforcing bar joint of the preceding element and the reinforcing bar joint of the trailing element are joined by a lap joint, cover concrete A joint structure for underground walls characterized by installing post-installed anchors in the concrete near the rebar joint of the rebar cage of the preceding element on the side.