JP3139367B2 - Continuous underground wall construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous underground wall construction method, and more particularly, to a method in which concrete is poured into a vertical groove excavated by a vertical excavator and the concrete is hardened. The present invention relates to a continuous underground wall construction method for constructing a continuous wall in which concrete in these flutes is continuously integrated by successively repeating in a body extending direction.

[0002]

2. Description of the Related Art A continuous underground wall construction method uses, for example, various flute excavators having a rectangular excavation cross-sectional shape to prevent collapse of a wall surface by filling muddy water into a flute during excavation. While excavating to a predetermined depth,
The filled muddy water is replaced with concrete and solidified to form a unit wall, and this unit wall is continuously formed in the extending direction of the wall to be constructed, and the plurality of unit walls are integrated. A continuous underground wall is to be constructed, and the continuous underground wall constructed in this manner is a retaining wall, a foundation pile, or a part of an underground structure that enables excavation work of the ground surrounded by the underground wall. It is used as

In such a continuous underground wall construction method, the work of replacing the muddy water in the flutes with concrete involves, for example, passing concrete from the lower part of the flute into the flute through a pipe such as a tremy pipe. It is performed by dropping and casting, but in order to facilitate the work of placing concrete through such pipes, and to launch concrete at a relatively high speed in vertical grooves. In many cases, concrete with good fluidity is used.

[0004] The concrete used for such a continuous underground wall construction method is required to ensure its fluidity.
Since a large amount of surplus water other than the water necessary for the hydration reaction of the concrete is contained, a large amount of breathing occurs after the concrete is cast and before it is hardened.

[0005] That is, the breathing is carried out in such a manner that water, which is a component having a small specific gravity in the concrete, or so-called breathing water in which a cement paste component and a mortar component are mixed, sew the gap between the aggregates in the concrete. It is a phenomenon that rises upward while making water paths,
In particular, in the continuous underground wall construction method, the concrete in a soft state receives a large pressure, so that a large amount of strong breathing occurs.

[0006] In addition, breathing in the continuous underground wall construction method often occurs near the inner wall surface of the vertical groove, that is, along the outer peripheral portion of the poured concrete, and many water channels are formed in such a portion. , The cement in this part of the concrete will be washed away,
Only poor quality concrete will be formed in this area.

[0007] In the conventional continuous underground wall construction method, the concrete on the outer peripheral portion is considered to be a portion having a cross-sectional defect, and for example, the cover of the concrete is largely removed.
A method has been adopted in which a design is made so that the strength can be exerted in a section excluding concrete of inferior quality.

[0008]

However, according to the conventional method of designing a concrete having a large cross-section by considering the outer peripheral portion of the concrete cast in the vertical groove as a cross-section defect portion, the continuous underground wall has a problem. It is necessary to perform the excavation work on the excavated cross section including the surplus part so as to have the cross section of the size including the part, and concrete is added by adding the extra concrete of the surplus part. Because of the necessity, construction costs and material costs increase.

On the other hand, it is conceivable to use underwater inseparable concrete as concrete for the continuous underground wall construction method so as not to cause a large amount of breathing. However, such concrete is generally expensive. Economical construction cannot be performed.

In view of the foregoing, the present invention has been made in view of such a conventional problem, and the design and construction of an efficient and economical continuous underground wall by keeping the area of a cross-sectional defect due to the occurrence of breathing small. It is an object of the present invention to provide a continuous underground wall construction method capable of performing the following.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and the gist of the invention is as follows.
The process of placing concrete in the flutes excavated and formed by the flute machine and curing it is sequentially repeated in the direction of extension of the wall to be constructed, and the concrete in these flutes is continuously integrated. In the continuous underground wall construction method for constructing a continuous wall, when concrete is poured into each of the vertical grooves, the concrete wall extends along the inner wall surface of the vertical groove, and has a U-shaped cross section. A continuous underground wall construction method characterized by artificially providing a draining groove for breathing water to which a wire mesh having a mesh size enough to prevent the coarse aggregate from passing so as to cover the opening surface. is there.

Here, in the above description, the artificially provided discharge groove is, for example, a groove shape having a U-shaped cross section other than a water channel as a discharge groove naturally generated in concrete due to the occurrence of breathing. Te, by extending disposed along the groove-like parts material wire mesh size of the eye so as not to pass through the way coarse aggregate covering the opening surface is mounted to the inner wall surface of the longitudinal groove, This means a discharge groove formed by separately attaching a discharge groove member that allows breathing water in concrete to flow into and move along the groove-shaped member.

According to the continuous underground wall construction method of the present invention, the artificial breathing water discharge groove extending along the inner wall surface of the vertical groove is formed by excavating a groove member, for example. Reinforcement cages for reinforcement installed prior to concrete placement in the flutes should be placed along the inner wall of the flutes when they are installed in the flutes. If it is attached in advance, by embedding this rebar cage in the vertical groove, the groove member is easily installed at a desired position, and an artificial discharge groove is formed.

[0014] When concrete is poured into the vertical groove after the groove member is extended along the inner wall surface of the vertical groove, the excess water in the concrete is removed with a slight amount of paste or mortar. Breathing water easily leaches into and flows into the discharge grooves formed by the groove members, and moves smoothly along the discharge grooves to be discharged.Therefore, many water paths due to breathing water are generated in concrete. And the ability to scour concrete with breathing water can be easily reduced.

That is, according to the continuous underground wall construction method of the present invention, the breathing water is accumulated in the discharge ditch and smoothly moved and discharged along the discharge ditch, so that many water paths are generated in the concrete. To prevent the generation of inferior concrete, and to discharge bleeding water intensively by the discharge groove, and the discharge groove is easily extended to the designed position. It is possible to design and construct a continuous underground wall with an efficient cross-section by using expensive special concrete without limiting the location where the cross-section defect occurs and causing many cross-section defects. It can be done economically without.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments, ie, embodiments of the present invention will be described below in detail with reference to the accompanying drawings. According to this embodiment, a flute 10 is formed by excavation using various well-known flute excavators conventionally used for a general underground wall construction method, and is shown in a partial plan view in FIG. As described above, after the reinforcing bar 11 is erected in the vertical groove 10, concrete is poured in such a manner as to replace the muddy water filled therein, and the unit wall 12 is formed by hardening the concrete. By continuously performing the operation of forming the unit wall bodies 12 in this way along the extension direction of the continuous underground wall to be constructed, the unit wall bodies 12 are integrated into a continuous It forms an underground wall. Then, when the concrete is poured into the excavated vertical groove 10, the continuous underground wall construction method of this embodiment is adopted.

That is, according to this embodiment, each longitudinal groove 1
Groove member 1 extending vertically along inner wall surface 13
Concrete is cast inside the vertical groove 10 in a state in which a plurality of 4 are arranged.

The groove member 14 is a member made of, for example, steel having a U-shaped cross section as shown in FIG. A large number of inflow windows 16 which are notched vertically along the portion are formed at intervals in the vertical direction.

Further, a wire mesh 19 having a mesh size enough to prevent coarse aggregate from passing therethrough is attached to the groove member 14 so as to cover the opening surface of the U-shaped cross section and the inflow window 16. When the concrete is poured, the concrete is controlled to flow into the inside of the groove member 14.

The groove member 14 is provided on a side surface of the reinforcing bar 11 when the reinforcing bar 11 is manufactured on the ground.
For example, it is attached via a spring member 17 or a rubber-like attachment string having elasticity, or a wire or a steel rod,
Together with the reinforcing bar 11, it will be installed inside the vertical groove 10.

In this embodiment, three pairs of long sides of the reinforcing bar 11 and one pair of short sides of the pair of short sides are provided.
The groove members 14 are attached to a total of eight places, and the number and interval of the groove members 14 or the width, height, shape, and the like of the groove members 14 are determined by the quality of the concrete used, the length of the longitudinal grooves 10 and the like. It is appropriately designed in consideration of the length, width, and the like.

Further, the groove member 14 attached to the reinforcing bar 11 releases the spring member 17 in the contracted and fixed state, for example, after the reinforcing bar 11 is built inside the longitudinal groove 10 and the urging force of the spring member 17 is released. By pressing the groove member 14 against the inner wall surface 13 of the vertical groove 10 or, when the groove member 14 is attached by a mounting cord, receiving the flow pressure of the concrete poured into the vertical groove 10 from the back and pressing the groove member 14 against the inner wall surface 13. By doing so, it can be easily extended in the vertical direction along the inner wall surface 13 of the vertical groove 10.

Further, according to this embodiment, the reinforced cage 11
Groove member 14 attached to one of a pair of short side portions of
Is a unit wall 12 formed in advance in the vertical groove 10.
Abutting on the end face 18 of the unit wall, discharge of breathing water at a connection portion of the adjacent unit wall bodies 12 is promoted, and strong connection integration of these continuous unit wall bodies 12 can be easily achieved. I can do it.

Then, according to the continuous underground wall construction method of this embodiment, a concrete placing operation is performed next so as to replace the muddy water in the vertical groove 10.

That is, the concrete placing operation is performed, for example, through a tremy tube suspended in the vertical groove 10 while maintaining the state in which the lower end portion is buried in the cast concrete. The concrete is sequentially lifted upward from the bottom of the vertical groove 10.

According to this embodiment, soft concrete with a large amount of surplus water is used in order to facilitate the work of placing concrete through the tremy tube. By discharging the generated breathing water quickly and smoothly, it is possible to prevent the formation of many water paths in the concrete and to build a high quality continuous underground wall.

That is, the surplus water in the concrete becomes breathing water and smoothly leaches into the inside of the groove member 14 through the inflow window 16 (see FIG. 2).
It will move smoothly upward along the sea and will be discharged, so it will not cause many water paths due to breathing water in the concrete, and easily reduce the power to scour the concrete of the breathing water Become.

Therefore, it is possible to effectively prevent the deterioration of the quality due to the generation of many water channels in the concrete, and to plan the sectional defect of the unit wall 12 only in the discharge groove portion by the groove member 14. In short, it is possible to design and construct a continuous underground wall with an efficient cross section without causing many cross-sectional defects and without taking a large cover portion.

The present invention is not limited to the embodiment of the above embodiment, but can be variously modified and adopted within the scope of the constitution described in the claims. For example, the discharge groove formed along the inner wall surface of the vertical groove is not limited to being provided only in the vertical direction,
Additionally or alternatively, they can be provided in the horizontal or oblique direction. Further, the wire member 19 does not necessarily need to be provided in the groove member 14 to cover the opening surface and the like.

[0030]

As described above in detail, according to the continuous underground wall construction method of the present invention, when concrete is poured into each excavated vertical groove, the concrete is placed along the inner wall surface of the vertical groove. Since it is configured by artificially providing a breathing water discharge groove that extends, breathing water is accumulated in the discharge groove and smoothly moved and discharged along this to reduce the area of the cross-sectional defect due to the occurrence of breathing. In this way, efficient and economical continuous underground wall design and construction can be easily performed.

[Brief description of the drawings]

FIG. 1 is a partial plan view illustrating an implementation state of a continuous underground wall construction method according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing an example of a groove member used for artificially providing a discharge groove along an inner wall surface of a vertical groove.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vertical groove 11 Reinforced basket 12 Unit wall 13 Inner wall surface 14 Groove member (discharge groove)

Claims (1)

(57) [Claims] 1. A step of placing concrete in a flute formed by a flute machine and curing the concrete in order in the direction of extension of a wall to be built, is sequentially repeated. In the continuous underground wall construction method for constructing a continuous wall in which the concrete is continuously integrated, when placing concrete in each of the vertical grooves, extending along the inner wall surface of the vertical grooves,
Artificially provide a breathing water discharge groove that has a U-shaped cross section and is fitted with a wire mesh that covers the opening surface and has a mesh size enough to prevent coarse aggregate from passing through. A continuous underground wall construction method.