JPH0953228A - Joint structure of underground continuous wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase shearing resistance. SOLUTION: A joint structure section is installed between linearly connected and formed preceding panel 12 and subsequent panel 14. The panels 12, 14 are composed of reinforced cylinders 121, 141 built into excavated ditches 120, 140 and wall bodies 122, 142 cured by placing concrete into the excavated ditches 120, 140 respectively. A circular cavity section 16 and a cutting section 18 are formed to a joint structure section 10 between the panels 12, 14. A center is set on a central axis in the wall thickness direction of the panels in the cavity section 16, and the cavity section 16 has a diameter of approximately one third of wall thickness, and is formed on the preceding panel 12 side. The cutting section 18 is formed by cutting and removing the end section of the wall body 122 of the preceding panel 12 when the excavated ditch 140 for the subsequent panel 14 is formed. The stirrup 141c of the subsequent panel 14 is arranged into the cavity section 16 so as to be projected to the preceding panel 12 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure for an underground continuous wall, and more particularly to a joint structure for an underground continuous wall which is linearly connected.

[0002]

2. Description of the Related Art As is well known, the underground continuous wall method excavates a grooved excavation hole from the ground while filling a stable liquid for preventing collapse of the excavation wall surface, and excavates a rebar cage in the grooved excavation hole. After building, concrete is poured to form a preceding panel of a predetermined length, and at the end of this preceding panel in the longitudinal direction,
This is a method of constructing a continuous underground wall of a predetermined shape by sequentially forming the succeeding panels by the same process as the forming process of the preceding panel.

In this type of construction method, the entire underground continuous wall is formed in a linear shape or a circular shape. by the way,
In the underground continuous wall of such an overall shape, in the case of a circular shape, when excavating the inside, the earth pressure acts toward the center of the circle, so, for example, if the planar shape of the panel is made substantially rectangular, The joint surfaces between the panels to be connected are pressure-bonded to each other, so that the waterproofness and the shear resistance are improved. However, the straight underground wall has the technical problems described below.

[0004]

That is, in a straight underground continuous wall, when the inside is excavated, earth pressure acts in parallel with the joint surface between the panels, and due to the action of this earth pressure, the joint surface becomes horizontal. This caused deterioration of the joint part and deterioration of the quality of the underground continuous wall, such as water leakage from the joint surface.

Therefore, in order to solve such a problem, for example, it is proposed that the joint surface between the panels is provided with concavities and convexities and the preceding panel and the succeeding panel are connected by concavity and convexity to improve the shear resistance. However, for example, when forming irregularities with a rotary hydro phrase excavator,
Since the depth of the unevenness cannot be sufficiently obtained, there is a problem that the shear resistance does not increase as expected.

The present invention has been made in view of such conventional problems, and an object thereof is to provide a joint structure for a continuous underground wall capable of sufficiently increasing shear resistance. Especially.

[0007]

In order to achieve the above-mentioned object, the present invention provides a joint structure for a continuous underground wall provided between a leading panel and a trailing panel which are linearly connected to each other. Adjacent to the joint between the preceding panel and the following panel, a cavity having a width and a length of approximately 1/3 of the wall thickness and having a circular or polygonal cross section formed on the preceding panel side. A cutting portion for cutting and removing the end portions of the preceding panel located on both sides of the hollow portion within the range of approximately 1/2 or less of the length of the hollow portion when forming the trailing panel. Is provided, and the end portion of the reinforcing bar cage of the trailing panel is installed in the hollow portion so as to project toward the leading panel side. According to the joint structure configured as described above, approximately 1/3 of the wall thickness is provided on the leading panel side.
When a hollow panel having a circular or polygonal cross section having a width and a length is provided and the trailing panel is formed, the end sides of the preceding panel located on both sides of the hollow portion are set to the length of the hollow portion. Since the cutting portion for cutting and removing is provided within a range of approximately ½ or less, it is possible to deepen the unevenness of the joint surface. Further, since the end of the reinforcing bar cage of the trailing panel is installed in the cavity so as to project toward the leading panel, the ends of the reinforcing bar cages of the leading and trailing panels are arranged close to each other. Shear resistance can be increased. To form a cavity in the preceding panel, for example, when forming the preceding panel, a circular locking pipe or polygonal pipe is installed on the end side of the excavation groove, and these are placed after concrete is placed. It can be easily formed by pulling out the pipe. Further, according to the present invention, since a concave groove portion can be formed in the cutting portion when the end portion of the preceding panel is cut, the shear resistance of the joint portion can be enhanced by the uneven structure of this portion.

[0008]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment of a joint structure for a continuous underground wall according to the present invention. The joint structure 10 shown in the figure is provided between a leading panel 12 and a trailing panel 14 which are linearly connected.

The leading and trailing panels 12, 14 excavate a rectangular planar excavation groove 120, 140.
Reinforcing bar cages 121 and 141 built in 20,140,
The excavation trenches 120 and 140 are composed of walls 122 and 142 in which concrete is poured and cured. Reinforcing cages 121 and 141 are the leading and trailing panels 1
At a predetermined distance from the outer surface of the wall thickness direction 2 and 14,
A plurality of main bars 121a and 141a arranged in two rows in the longitudinal direction of the wall bodies 122 and 142, and main bars 121a and 141a
A plurality of distribution muscles 1 arranged laterally so as to connect between them
21b, 141b and a plurality of stirrup muscles 121 arranged so as to connect the muscles for distributing force 121b, 141b.
c, 141c.

The stirrup muscle 121c of the preceding panel 12
Is bent in an inverted V shape at the end on the joint structure 10 side, and the stirrup rib 141c of the trailing panel 14 is
Has an end bent on the side of the joint structure 10 in a V shape,
These stirrup streaks 121c and 141c are installed to be parallel to each other and close to each other.

The joint structure 10 between the leading and trailing panels 14 is provided with a circular cavity 16 and a cutting portion 18. The circular hollow portion 16 has its center located on the central axis of the panel in the wall thickness direction, and has a wall thickness of approximately 1
It has a diameter of about / 3 and is formed on the front panel 12 side. When forming the leading panel 12, the hollow portion 16 is adjacent to the joint with the trailing panel 14 and the circular locking pipe 20 is inserted into the excavation groove 120 in advance. Is formed and then the locking pipe 20 is pulled out.

The cutting portion 18 is formed by cutting and removing the end portion of the wall body 122 of the preceding panel 12 when forming the digging groove 140 for the trailing panel 14. The cutting allowance at this time is as shown by the diagonal lines in FIG.
The length of the cavity 16 is set to be approximately 1/2 or less, and in this embodiment, the ends of the wall bodies 122 of the preceding panel 12 located on both sides of the cavity 16 have circular circular cavity 16 ends. It has been cut off to the center.

The rebar cage 141 of the trailing panel 14 has a V-shaped bent stirrup streak 141c disposed in the cavity 16 so as to project toward the leading panel 12. Next, a method of forming the joint structure portion 10 having such a configuration will be described. When constructing a straight underground continuous wall, first, as shown in FIG. 2, a rectangular excavation groove 120 for the preceding panel 12 is excavated. The excavator 22 used at this time is, for example, a hydrophrase excavator 22 as shown in FIG.

The excavator 22 has a main body 22a suspended and supported by a crane and a plurality of excavating drums 22b rotatably installed at the lower end of the main body 22a, and excavates while supplying a stable liquid. By rotating the drum 22b, the ground is excavated or the concrete wall body is cut. When the excavator 22 excavates the excavation groove 120 to a predetermined depth, the excavator 22 comes into contact with the edge on the side of the joint with the trailing panel 14, and the center of the excavation groove 120 is on the center axis in the width direction. The hollow tubular locking pipe 20 is inserted and installed so as to be positioned, and the rebar cage 121 is installed so that the stirrup stylus 121c bent in an inverted V shape is close to the outer periphery of the locking pipe 20. .

Then, in this state, the stabilizing liquid in the excavation groove 120 is replaced with concrete, and the concrete is hardened to form the rectangular wall body 122. At this time, the rocking pipe 20 is pulled out at a stage where the strength of the cast concrete is developed to some extent, whereby the hollow portion 16 having a circular cross section is formed over the entire length of the wall body 122. When the leading panel 12 is formed in this manner, a digging groove 140 for the trailing panel 14 is diggingly formed on the side of the leading panel 12.

In excavating the excavation groove 140, the same hydrophrase excavator 22 as described above is used,
Cutting is performed to cut the ends of the wall bodies 122 located on both sides of the cavity 16. The cutting allowance at this time may be in the range of approximately ½ or less of the length of the hollow portion 16, but in order to install the stirrup muscle 141c of the rebar cage 141 in the hollow portion 16, the hollow portion is required. It is desirable to cut to about the center of 16. When such cutting is performed, the digging groove 140 on the trailing panel 14 side has a semicircular shape protruding toward the leading panel 12 side at the hollow portion 16.

The cutting on the side of the leading panel 12 may be performed over the entire length of the wall 122, but in order to increase the shear resistance, the cutting is performed under the root cutting surface 20 to 20.
It may be performed up to about 30 cm. Excavation trench 14 as described above
When the excavation formation of 0 is performed to a predetermined depth, then the reinforcing bar 141 is built and concrete is placed, and the wall body 142 of the trailing panel 14 is constructed.

At this time, the rebar cage 141 has a stirrup bar 141 provided on the end side thereof and bent in a dogleg shape.
c is installed so as to be located inside the semicircular cavity 16. In this case, since the trailing panel 14 is a leading panel with respect to the trailing panels that are sequentially constructed after that, the locking pipe 20 is installed on the left end side in FIG. The cavity 16 is formed similarly to the preceding panel 12 described above.

Now, according to the joint structure portion 10 constructed as described above, approximately 1/3 of the wall thickness is provided on the front panel 12 side.
When a cavity 16 having a circular cross section having a width and a length of 10 is provided and the trailing panel 14 is formed, the end sides of the leading panel 12 located on both sides of the cavity 16 are connected to the cavity 16 concerned.
Since the cutting portion 18 that cuts and removes to almost the center position is provided, the joint surface has a portion protruding to the side of the preceding panel 12 with a length of approximately 1/6 of the wall thickness, thereby deepening the unevenness of the joint surface. It becomes possible to improve the shear resistance.

Further, the trailing panel 14 is placed in the cavity 16.
Since the end portion of the rebar cage 141 of the above is installed so as to project toward the leading panel 12, the leading and trailing panels 12, 1
The end portions of the four reinforcing bar cages 121 and 141 are arranged close to each other,
This can also increase the shear resistance. further,
If the cutting portion 18 is not provided over the entire length of the wall body 122 and is stopped slightly below the root cutting surface, in the portion deeper than the cutting portion 18, the cavity 16 having a circular cross section is provided with the trailing panel 14 side. Since the concrete is filled, the concavo-convex fitting of this portion also strengthens the degree of connection between the leading and trailing panels 12 and 14.

FIG. 6 shows another embodiment of the joint structure portion 10 according to the present invention, and only the characteristic points will be described below. In the embodiment shown in the figure, when the leading panel 12 is formed, the hollow portion 16 is provided, and when the trailing panel 14 is formed, the ends of the wall bodies 122 on both sides of the hollow portion 16 are cut and cut. Providing the portion 18 is the same as in the above embodiment, but when the cutting portion 18 is provided,
Recessed groove 2 protruding toward the wall 122 side of the preceding panel 12
4 is provided.

The concave groove portion 24 is formed up to slightly below the root cutting surface, and the groove 24 is filled with concrete when the rear panel 14 is formed. According to the joint structure portion 10a having such a configuration, the leading and trailing panels 12, 1
An uneven portion is added to the joint surface of No. 4, and the shear resistance of the joint portion can be enhanced also by this uneven structure. In the above-mentioned embodiment, the hollow portion 16 has a circular cross-sectional shape, but the present invention is not limited to this. For example, a polygonal shape such as a quadrangle or a pentagon, an ellipse, and a long shape. It may have a shape such as a circle or a trapezoid.

[0023]

As described above in detail in the embodiments,
According to the joint structure of the underground continuous wall according to the present invention, in particular,
It is possible to greatly improve the shear resistance of a straight underground wall.

[Brief description of drawings]

FIG. 1 is an explanatory plan view showing an embodiment of a joint structure according to the present invention.

FIG. 2 is a plan explanatory diagram of a forming process of a preceding panel when forming the joint structure shown in FIG.

FIG. 3 is a plan explanatory view of a preceding panel formed in the step shown in FIG.

4 is a plan explanatory view of a step of forming a trailing panel when forming the joint structure shown in FIG. 1. FIG.

FIG. 5 is an explanatory view of an excavator used when forming the joint structure of the present invention.

FIG. 6 is an explanatory plan view showing another embodiment of the joint structure according to the present invention.

[Explanation of symbols]

 10, 10a Joint structure part 12 Leading panel 120 Excavation groove 121 Reinforcing bar cage 121a Main bar 121b Force distribution muscle 121c Stirrup muscle 14 Back panel 140 Excavation groove 141 Reinforcing bar cage 141a Main bar 141b Force distribution muscle 141c Stirrup muscle 16 Cavity part 18 Cutting 20 Rocking pipe 22 Excavator 24 Groove

Claims (2)

[Claims] 1. In a joint structure of an underground continuous wall provided between a leading panel and a trailing panel linearly connected to each other, adjacent to a joint between the leading panel and the trailing panel, A hollow portion having a width and a length of approximately 1/3 of the wall thickness and having a circular or polygonal cross section formed on the side of the preceding panel, and both sides of the hollow portion when forming the trailing panel. And a cutting portion that cuts the end portion side of the preceding panel located within a range of approximately 1/2 or less of the length of the cavity portion, and the end portion of the reinforcing bar cage of the trailing panel is set to the preceding panel. A joint structure for a continuous underground wall, wherein the joint structure is installed in the cavity so as to project to the side. 2. The joint structure of the underground continuous wall according to claim 1, wherein a concave groove is formed in the cutting portion when the end portion of the preceding panel is cut.