JPS6132450B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing a connection part of an underground continuous wall of an underground structure.

When constructing an underground continuous wall, generally, a long underground continuous wall is divided into several elements, and each element is connected next to the preceding element constructed earlier and constructed in sequence. Constructing a continuous wall in the form of a length is carried out. In this case, in order to ensure that the connection between each element, that is, the vertical joint, has sufficient connection strength, it is necessary to overlap (overlap) some of the reinforcing bars of adjacent elements. Figure 1 shows an example of the construction state of the lap part. A reinforcing bar cage 1a is projected in advance to overlap with 1b. When constructing the element B on the trailing side, the reinforcing bar cage 1b assembled in advance on the ground is inserted into the excavated trench underground, and both the reinforcing bar cage 1a on the leading side and the reinforcing bar cage 1b on the trailing side are installed. A lap reinforcing bar 2 that spans and wraps is inserted, and both reinforcing bar cages 1a and 1b are overlapped with each other to form a lap joint.
After that, concrete 3b was poured, and element B on the trailing side was connected to element A on the leading side.

In this way, the reinforcing bars of adjacent elements A and B are partially lapped together to connect the elements, but the connected state obtained in this way is not necessarily satisfactory. This is because, as can be inferred from the state shown in Fig. 1, the reinforcing bar cages 1a and 1b of both elements A and B, which are adjacent to each other, only partially overlap. This is because no shear reinforcing bars for engaging 1a and 1b are formed in this joint portion. Therefore, in order to obtain a more reliable connection between both elements A and B,
Stirrup reinforcing bars are required to span the horizontal reinforcing bars of both elements A and B.
However, the work of installing stirrup reinforcing bars underground is extremely troublesome because it must be done in a stabilizing liquid.For this reason, in the past, it was only possible to simply overlap the reinforcing bars of both elements; Conventional construction methods for vertical joints in underground continuous walls have had major drawbacks.

This invention was made in order to eliminate the above-mentioned drawbacks, and its purpose is to make it possible to cross over stirrup reinforcing bars that span between each reinforcing bar of adjacent elements with a relatively simple operation. The object of the present invention is to provide a method that further increases the connection strength between elements and enables construction of a high-strength and highly reliable underground continuous wall.

That is, this invention involves inserting a reinforcing bar cage into an underground excavation trench from above ground, pouring concrete, and sequentially constructing elements that form part of an underground continuous wall, while also wrapping some of the reinforcing bars of adjacent elements into each other. This relates to the construction method of an underground continuous wall that connects each element laterally by
The feature is that stirrup reinforcing bars are fixed to a straight steel material at appropriate intervals to form comb-shaped shear reinforcing bars, which are then attached to the lap portion in pairs, and the stirrup reinforcing bars are moved. , to span horizontally between the main reinforcing bars of adjacent elements, and then concrete is poured to construct the transition side element.

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

Figures 2a to 2g show the work order for explaining one embodiment of the method of constructing the connection part of an underground continuous wall according to the present invention.First, as shown in Figure 2a, the construction part of the preceding element is constructed. For example, as shown in FIG. 3, a reinforcing bar cage 1a constructed by assembling a plurality of vertical reinforcing bars 5a and horizontal reinforcing bars 6a is inserted into an underground trench 4a excavated in the ground, and then inserted between the partition plates 7a and 7a'. Concrete 3a is placed in the underground trench 4a and construction is carried out as shown in Figure 2b. Next, as shown in FIG. 3C, an underground trench 4b is excavated in the ground in the trailing element construction area, and the movable pull-out plate 8a attached to the end of the leading reinforcing bar cage 1a is pulled out from the box 9a. This movable pull-out plate 8a is provided to prevent soil from entering the inside of the box 9a, that is, the portion that will later become a lap portion, when excavating the underground trench 4b of the trailing element. Then, as shown in Fig. 2d, the reinforcing bar cage 1b, which has a box 9b only at one end (the right end in the figure), is placed in the underground trench 4b with horizontal reinforcing bars 6b at the other end.
is inserted so as to overlap the horizontal reinforcing bar 6a protruding inside the box 9a of the preceding element A. At the end of the reinforcing bar cage 1b of the trailing element B connected to the leading element A, the interval between the horizontal reinforcing bars 6b, 6b is narrower than in other parts, as shown in FIG. It is designed so that it does not interfere with the horizontal reinforcing bars 6a of the preceding element A. In addition, instead of narrowing the width of the horizontal reinforcing bars 6b, 6b of the reinforcing bar cage 1b on the trailing side,
As shown in FIG. 4, parallel lapping reinforcing bars 2, 2 with narrower spacing may be fixed to the ends of the reinforcing bar cage 1b so as to overlap with the end 6a of the preceding reinforcing bar cage 1a.

Once the ends of the reinforcing bar cages 1a and 1b have been wrapped in this way, next, as shown in FIG. Insert and arrange as shown in Figure 2e. This shear reinforcing bar 10 is formed into a comb shape by fixing a plurality of stirrup reinforcing bars 12, 12, . The comb-shaped shear reinforcing bars 10 are arranged in pairs in opposing directions, and the stirrup reinforcing bars 12, 12' of each pair are slidable relative to each other by ring members 13, 13', respectively. This pair of shear reinforcing bars 1
0 and 10' are inserted into the lap portion with the steel members 11 and 11' spaced apart by the length of the stirrup reinforcing bars 12 (see FIG. 6). Note that the tips of each of the stirrup reinforcing bars 12 are bent downward into a hook shape. Next, with the shear reinforcing bars 10, 10' slightly lifted, operate from the ground to move the steel members 11, 11' closer to each other as shown in Fig. 2(f). 12, 12...... protrude outward, and the tips are connected to the leading side horizontal reinforcing bars 6a, 6 as shown in FIG.
When the point a is exceeded, the shear reinforcing bars 10, 10' are lowered by their own weight, and the stirrup reinforcing bars 12, 12...
The key part at the tip of the horizontal reinforcing bars 6a, 6a is hooked and locked. Thereafter, concrete 3b is poured into the underground trench 4b as shown in FIG. 2g, and the transition side element B is constructed to be continuous with the preceding side element A. As a result, very good connection strength can be obtained between both elements A and B due to the shear reinforcing bars 10 and 10'. Furthermore, the reinforcing effect is further increased by the hook portion at the tip of the stirrup reinforcing bar 12 being caught on the horizontal reinforcing bar 6a. During the above work, a pair of shear reinforcing bars 10,
10' may be moved using an underwater jack, but as shown in FIG.
A rope, wire, etc., is attached to the lower end of 1'.
4' is fixed at one end, and the cables 14, 14' are wrapped around the horizontal reinforcing bars 6b or the wrapping reinforcing bars 2 in advance and then pulled out to the ground.
The work becomes easier if the shear reinforcing bars 10, 10' are moved by pulling the reinforcing bars 10, 10' by a predetermined length. Further, friction can be reduced by partially fitting a sleeper 15 into the horizontal reinforcing bar 6b on which the cable 14 slides, as shown in FIG.

As described above, with the method according to the present invention, it is possible to extend the stirrup reinforcing bars across the reinforcing bars of adjacent elements with a relatively simple operation, thereby further increasing the strength of the connection between the elements. It is possible to construct underground continuous walls with high strength and reliable structure.

[Brief explanation of the drawing]

Fig. 1 is a plan sectional view showing one state of construction by a conventional method, Fig. 2 is a plan sectional view showing an embodiment of the construction method according to the present invention, and Fig. 3 shows the reinforcing bar cage taken out. 4 is a plan sectional view showing another configuration example of the reinforcing bar cage, FIG. 5 is a perspective view showing the state before the shear reinforcing bars are moved, and FIG. 6 is the state after the shear reinforcing bars are moved. The perspective view shown in FIG. 7 is a sectional view taken along the line DD in FIG. 6. A... Leading side element, B... Trailing side element, 1a, 1b... Rebar cage, 3a, 3b... Concrete, 4a, 4b... Underground trench, 6a, 6b
...Horizontal reinforcing bar, 10,10'...Shear reinforcement (composed of 11, 12, 13), 11,
11'...Steel material, 12, 12'...Reinforcing bar for stirrup, 13...Ring member.

Claims (1)

[Claims] 1. Insert reinforcing bar cages from above ground into underground excavation trenches and then pour concrete to construct the elements that form part of the underground continuous wall in sequence. At the same time, by wrapping some of the reinforcing bars of adjacent elements together, each In the construction method for reinforcing vertical joints of underground continuous walls that connect elements laterally, multiple stirrup reinforcing bars are fixed in advance to straight steel or reinforcing bars in the horizontal direction at appropriate intervals to provide comb-shaped shear reinforcement. The shear reinforcing bars are formed into pairs with opposite directions, and the overlapping stirrup reinforcing bars are slidably connected with a ring member, and then the shear reinforcing bars of this pair are connected so that they can slide. After vertically inserting the stirrup reinforcing bars into the lap parts of each of the above elements so that they face the width direction of the excavation trench, operate the pair of shear reinforcing bars from the ground to move the stirrup reinforcing bars in the direction that protrudes outward. A construction method for reinforcing a vertical joint of an underground continuous wall, which is characterized by hooking the tip of the stirrup reinforcing bar to the horizontal reinforcing bar of the leading element, and then pouring concrete to construct the trailing element. .