JPH0660492B2 - Vertical underground construction method for continuous underground wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Field of Application >> The present invention relates to a method for vertically joining continuous underground walls, which is particularly suitable for joining deep underground walls.

<Prior art> The conventional method of joining vertical joints between underground walls is mainly the lap joint type of horizontal reinforcement of underground walls. This type has a partition plate such as a partition steel plate equipped with shear connectors and reinforcing materials on the joint surface between the leading wall and the trailing wall, and a partition plate such as a precast plate with an uneven surface, and between these walls between them. It has a mechanism to transmit shearing force.

<Problems to be solved by the invention> However, the mud cake is apt to adhere to the partition plate sandwiched between the both walls, and this adhesion causes deterioration of the adhesive force between the partition plate and the wall concrete. Easily, the water-stopping property is lowered, the shear transmission is apt to be lowered, and the partial function of the splice part is apt to be lowered.

And this is not a problem in the underground wall of a relatively shallow depth, but when it is applied to a deep underground wall of, for example, 50 to 100 m, it extremely appears, construction is difficult, and economically. Although it is expensive, the above-mentioned problems are likely to occur. Therefore, it is almost impossible to construct a deep underground wall by the above conventional method.

The present invention has been made in view of the above problems, and an object thereof is that the structure of the joint portion is simple, the construction is easy, and the integration function of the joint portion can be improved. The purpose of the present invention is to provide a vertical underground construction method for continuous underground walls that is highly waterproof and can be constructed economically.

<< Means for Solving Problems >> In order to achieve the above-mentioned object, the method of the present invention is to roughen the concrete surface of the vertical joint of the preceding underground wall by cutting and cut the concrete surface. By doing this, a notch with a rough surface is formed along the vertical direction, and then the concrete forming the trailing underground wall is placed in the joint section and the ground walls are punched together by a tenon structure. Characterized by succession.

<Example> Hereinafter, an example of the method of the present invention will be described in detail with reference to the drawings.

1 to 3 show a first embodiment of the method of the present invention.

In this example, the preceding ground is intermittently constructed by placing concrete in each of the vertically excavated vertical holes leaving the intermediate ground, and the intermediate ground between the constructed preceding walls is excavated. At this time, by excavating while cutting the end face of the preceding wall, the roughened joint surface is exposed, and by placing concrete in this intermediate hole, the trailing wall is spliced to the preceding wall. is there.

First, in FIG. 1, a leading wall 1 forming a negative element of a continuous underground wall is made of concrete reinforced by reinforcing steel in a vertical hole 3 of large depth which is intermittently excavated leaving an intermediate ground 2. It was constructed intermittently by casting each.

Then, a low-strength block 4 made of low-strength concrete, foamed resin, or the like is set in the longitudinal direction in the center of the joining portion to the trailing wall 6 of the preceding wall 1 in advance in the longitudinal direction in the rebar cage of the preceding wall 1. Has been done.

Next, in the intermediate ground 2, as shown in FIG. 2, excavated vertical holes 2'are formed. At the time of this excavation, in the stabilizing solution 5 filled in the vertical hole 2, the end surface of the joint portion of the leading wall 1 and the portion of the low-strength block 4 are roughened by a cutting means such as a drum type cutter. Cutting while surfaceizing. As a result, concavities and convexities 1a are formed in the joint portion of the preceding wall 1, and mortises 6a having concavities and convexities 1b are formed along the vertical direction at positions where the low-strength block 4 has been removed.

Then, as shown in FIG. 2, by placing concrete reinforced with reinforcing bars inside the intermediate vertical hole 2 ',
As shown in the figure, a mortise hole 6a is formed in the joint portion of the leading wall 1 and the trailing wall 6, and a joint structure in which the entire joint surface is roughened is formed and jointed together.

FIG. 4 shows an example of the reinforcement of the continuous underground wall constructed as described above. The horizontal reinforcements of the preceding wall 1 and the following wall 6 are not connected, but Since the reinforcing bar 10 of the trailing wall 6 is a reinforcing bar cage having a shape protruding along the shape of the mortise hole 6a, a required shear reinforcement is exerted.

Next, FIG. 5 shows a completed state of the splice part according to the second embodiment of the method of the present invention.

In this embodiment, a mortise 6 is provided outside the cross section of the leading wall 1.
This is a case where b is provided and excavation is performed so that the center portion of the leading wall 1 has a protruding shape. The trailing wall 6 is formed with irregularities for receiving it. Contrary to the above, in this embodiment, as shown on the right side of the drawing, the low-strength blocks 4 are arranged on both sides of the forming part of the mortise hole 6b in the joining portion, and the trailing wall 6 is formed. When excavating, the unevenness 1c may be provided on the mortise surface while removing it by cutting or the like.

In each of the examples, the method of excavating the intermediate ground between the leading walls 1 and joining the trailing wall to this was applied, but the method of adding the trailing wall to the leading wall one by one and extending it Can also be applied.

In addition, when excavating the vertical hole formed by the trailing wall,
If the excavation width of a drum cutter is less than the wall thickness,
A method of excavating the portion connecting the mortises and then excavating the other portion can also be adopted.

<Effects of the Invention> As described in detail in each of the above examples, according to the method of the present invention, since there is no need for a shear connector reinforcing steel material or the like in the joint portion of the continuous underground wall, there is no cutout at the time of excavation. It can be connected with a strong tenon structure simply by adding a forming process, and construction is extremely easy and economical.

Further, the mortise structure improves the water blocking performance and makes it possible to obtain an extremely strong piecing surface.

[Brief description of drawings]

1 to 3 are plan views showing the order of construction according to the first embodiment of the method of the present invention, FIG. 4 is a cross-sectional view showing an example of bar arrangement in the same construction method, and FIG. 5 is of the method of the present invention. It is a top view which shows the completion state by 2nd Example. 1 ... Leading wall, 1a ... Asperity 1b, 1b ... Mortise surface asperity 4 ... Low strength block 6 ... Trailing wall, 6a, 6b ... Mortise

Claims (1)

[Claims] 1. A concrete surface of a vertical jointing portion of a preceding underground wall is roughened by cutting, and a cutout portion of the rough surface is formed along the longitudinal direction by cutting the concrete surface. A vertical jointing method for continuous underground walls, which is characterized in that concrete forming a succeeding underground wall is placed at the connecting portion and the underground walls are integrally connected by a mortise structure.