JP3067603B2 - Construction method of steel cage in underground diaphragm wall 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 method for installing a reinforcing cage in an underground continuous wall method.

[0002]

2. Description of the Related Art As is well known, the underground diaphragm wall method excavates a grooved excavation hole from the ground while filling it with a stable liquid for preventing collapse of the excavated wall surface, and excavates a rebar cage in the grooved excavation hole. After being erected, concrete is cast to form a panel-shaped leading wall of a predetermined length, and a panel-shaped trailing wall is attached to the panel-shaped trailing wall at the longitudinal end of the panel-shaped leading wall. This is a method in which a continuous underground wall having a predetermined shape is constructed by sequentially connecting and forming the underground wall in substantially the same step as the wall forming step.

[0003] In this type of construction method, recently, high construction accuracy is required. However, in order to construct an underground continuous wall with high accuracy, a reinforcing steel cage buried in a panel-like wall is required. It is necessary to erected accurately at a predetermined position in a grooved excavation hole. Therefore, conventionally, in order to secure the installation accuracy of the reinforcing rod cage, the reinforcing bars were built by the following method. The rebar cage is suspended and supported by a lifting machine such as a crane. The rebar cage is positioned above the excavation hole, and the rebar cage is slowly moved while confirming the verticality in two-dimensional directions (X and Y directions) by transit. It was suspended inside the borehole. However, the technical problems described below have been pointed out in such a conventional method of building a reinforcing rod cage.

[0004]

That is, in the above-described conventional mounting method, the reinforcing rod cage is suspended slowly above the excavation hole while being suspended, so that the rebar cage is unbalanced when suspended. However, the reinforcing rod cage is shaken back and forth and right and left above the excavation hole, so that it is difficult to measure the verticality by the transit, and as a result, it has been difficult to secure the accuracy of the reinforcing rod cage installation.

[0005] In addition, the measurement of verticality by transit takes a very long time due to the fact that the reinforcing bar cage is shaken, which has been a factor of reducing the construction efficiency. The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a construction of a reinforced cage in an underground continuous wall construction method in which the installation accuracy can be secured by a relatively simple operation. It is to provide an embedding method.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a panel-like construction in which a steel cage is erected in a trench excavated in the ground and concrete is cast. In the underground continuous wall construction method of sequentially forming and forming a wall body, when the reinforcing bar cage is built in the excavation hole, a pair of positioning guide members arranged in a C shape are fixed on the excavation hole, Insert the lower end side of the suspended reinforcing bar between the guide members from the enlarged interval side, and move in parallel the reduced interval side to a position where both longitudinal edges of the rebar cage contact the inner surface of the guide member. Thereafter, the rebar cage is installed in the excavation hole while maintaining the contact state. In the rebar cage mounting method configured as described above, the contact position between the longitudinal end edges of the rebar cage and the inner surface of the guide member is determined by opening a pair of positioning guide members arranged in a C shape. If the angle and the maximum length in the longitudinal direction of the rebar cage are known, the angle can be obtained. Therefore, when the guide member is fixed above the excavation hole so that the determined contact position is the position where the reinforcement cage is erected with respect to the grooved excavation hole, both longitudinal edges of the reinforcement cage contact the inner surface of the guide member. If the rebar cage is placed in the excavation hole while the abutment state is maintained while the abutment state is maintained, the rebar cage can be accurately built. In this case, when the both ends in the longitudinal direction of the reinforcing cage are brought into contact with the inner surface of the guide member,
The run-out of the reinforced basket supported by suspension is eliminated. The enlarged interval side of the pair of positioning guide members is set to be at least longer than the maximum length in the longitudinal direction of the reinforcing bar cage. The guide member may be fixed to the work floor by, for example, an anchor bolt. In the method for installing a reinforcing bar cage according to the present invention, the positioning guide member can provide a marking display corresponding to the contact position with the edge of the reinforcing bar cage. When a guide member having such a configuration is employed, the workability when the longitudinal ends of the reinforcing rod cage are moved in parallel to the reduction interval side to a position where they come into contact with the inner surface of the guide member is significantly improved. Further, in the method for installing a reinforcing bar cage according to the present invention, a guide piece that is in contact with a side edge of the reinforcing bar cage can be provided on the inner surface side of the positioning guide member. When the guide member having such a configuration is employed, the state of the reinforcing bar cage is stabilized, so that it is easier to further secure the installation accuracy.

[0007]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The first embodiment described below is a case where the present invention is applied to the construction of a circular or polygonal underground continuous wall, and the second and third embodiments are directed to the case where the present invention is applied to a linear underground continuous wall. In the example shown in FIG.

[0008]

FIG. 1 and FIG. 2 show a first embodiment of a method for installing a reinforcing rod cage in an underground continuous wall method according to the present invention. The construction method of the reinforcing cage 10 shown in FIG. 1 is applied to the case where the polygonal underground continuous wall 12 is constructed by the underground continuous wall construction method. When constructing the polygonal underground continuous wall 12, first, a rectangular (portion shown by a dotted line in FIG. 1) groove-shaped excavation hole 14 is excavated in the ground to a predetermined depth while filling with a stable liquid, After the rebar cage 10 is built in the excavation hole 14, concrete is cast to construct the panel-shaped preceding wall body 16.

When the construction of the leading wall 16 is completed, the panel-like trailing wall 1 is formed at both ends in the longitudinal direction by the same process.
8 are connected and formed. When the trailing wall 18 is formed, both ends in the longitudinal direction of the leading wall 16 are cut into a substantially triangular shape, and the longitudinal axis of the leading wall 16 and the trailing wall 18 are cut.
The polygonal underground continuous wall 12 is constructed by obliquely intersecting the longitudinal axis of.

Reinforcing cage 10 buried in preceding wall 16
Has a substantially trapezoidal planar shape because of cutting both ends of the preceding wall body 16 into a triangular shape when forming the trailing wall body 18, and includes a plurality of main bars 10a and a plurality of force distribution bars. 10b
, A plurality of stirrup bars 10c, a pair of partition iron plates 10d, and a pair of H-shaped steels 10e.
The plurality of main bars 10a are arranged in two rows along the longitudinal direction of the wall body 16, and extend in the vertical direction of the wall body 16 at predetermined intervals. The plurality of distribution bars 10b are arranged so as to be substantially horizontal along the longitudinal axis direction of the wall 16 so as to connect the plurality of main bars 10a arranged in two rows. The stirrup bars 10c are arranged so as to be orthogonal to the longitudinal direction of the wall 16 so as to connect the distribution bars 10b.

The partitioning iron plates 10d are fixed to the ends of the force distribution bars 10b so as to be located at both ends of the reinforcing bar cage 10 in the longitudinal direction. The H-section steel 10e is fixed to the iron plate 10d so as to protrude outward at the center in the width direction of each partition iron plate 10d. In the case of the present embodiment, when the reinforcing bar cage 10 configured as described above is installed in the excavation groove 14, the rebar cage 10 is performed by a method described below.

When building the reinforcing rod cage 10, the excavation hole 1
A pair of positioning guide members 20 are fixed on the top 4. The guide member 20 includes a square beam 20a and a pair of mounting plates 20b fixed to both ends of the beam 20a. A pair of guide members 20 are
The center axes l _{1 and} l _{2 of a} are fixed by anchor bolts 24 to a guide wall 22 provided at the upper end of the excavation hole 14 so as to have a substantially C-shape.

In this case, the fixed state of the guide member 20 is as follows.
As shown by phantom lines in FIG.
Center axis l of 20a_1,l_TwoIs the length of the borehole 14
In the direction O, and each of the
Central axis l of beam 20a_1,l _TwoAngle becomes equal angle θ
Set to be. And for each beam 20a
Is located on the central axis (C / L) in the width direction of the borehole 14.
Marking display 26 is provided with a felt pen etc.
Can be

The position of the marking display 26 is
Although it can be set from the center of the excavation hole 14 in the width direction, since the maximum length in the longitudinal direction of the rebar cage 10 is known, it is set by measuring the length between the guide members 20 corresponding to this maximum length. You can also. In this case, the angle θ is selected such that the enlarged interval side (the lower side in FIG. 1) of the pair of guide members 20 arranged in a C shape is larger than the maximum length in the longitudinal direction of the rebar cage 10.

When the installation of the positioning guide member 20 is completed as described above, the rebar basket 10 is suspended and supported by a lifting machine such as a crane, and the building is performed. At this time, when the rebar basket 10 is built, the short side of the trapezoidal rebar basket 10 is positioned on the upper side, and the lower end side of the rebar basket 10 is inserted between the guide members 20 from the enlarged interval side of the guide member 20. I do.

Then, the reinforcing rod cage 10 is moved in parallel to the reduction interval side with the lower end inserted between the guide members 20 (as indicated by the arrow in FIG. 1 from above to below),
The H-shaped steel 10e of the rebar cage 10 is brought into contact with the inner surface of the beam 20a of each guide member 20. At this time, if the shape and dimensions of the rebar basket 10 are as designed, each H-shaped steel 10e
The contact is made at the mark display 26.

When the H-section steels 10e at both ends of the reinforcing cage 10 come into contact with the beam 20a, the reinforcing cage 10 is slowly suspended downward while maintaining this state, and the excavation hole 1 is formed.
4 is installed. At this time, the verticality of the rebar basket 10 in the two-dimensional direction is checked while checking by transit. Now, according to the construction method of the reinforcing cage 10 configured as described above, the H-shaped steels 10e provided at both ends in the longitudinal direction of the reinforcing cage 10 are brought into contact with the inner surface of the beam 20a of the guide member 20. In addition, since the suspension of the reinforced cage 10 supported by suspension is eliminated, the verticality can be easily and quickly confirmed by the transit, and the construction accuracy can be kept high.

In the case of this embodiment, since the contact position of the reinforcing rod cage 10 is marked on the beam 20a of the guide member 20 in advance, the parallel movement of the reinforcing rod basket 10 to the reduction interval side is performed. Workability becomes very good.

[0019]

FIG. 3 shows a second embodiment of the method for building a reinforced cage according to the present invention. The same or corresponding parts as those of the above embodiment are denoted by the same reference numerals and description thereof is omitted. In addition, only the characteristic points will be described below. In the embodiment shown in the figure, the construction method of the present invention is applied when the underground continuous wall 12a is formed in a straight line. Underground wall 1
In the construction of 2a, a rectangular grooved excavation hole 14a is excavated and formed, and a reinforcing bar cage 10a is erected to form a panel-shaped preceding wall 16a. Is formed.

The rebar basket 10a is formed in a substantially similar shape with an outer shape smaller than the rectangular excavation hole 14a.
Has distribution muscles and stirrup muscles. This reinforced basket 10
When a is to be built in the excavation hole 14a, a pair of guide members 20 'are installed in a C-shape on the excavation hole 14a as in the above-described embodiment. In this embodiment, the portion where the longitudinal edge (corner) of the reinforcing bar 10 abuts on the beam 20a is located on the upper side in the width direction of the excavation hole 14a. Considering the width, the edge is the beam 20a.
Is provided with a marking 26 at a position where the center in the width direction of the rebar cage 10a and the center in the width direction of the excavation hole 14a coincide with each other.

Further, the front side of the marking display 26,
That is, on the enlarged interval side, the wedge-shaped guide piece 20c is fixed to the inner surface side of the beam 20a. This guide piece 2
The angle 0c matches the angle θ of the beam 20a of each guide member 20. When the positioning guide member 20 'configured as described above is used, when the rebar cage 10a having the lower end inserted between the guide members 20' is moved in parallel to the reduction interval side, the guide piece is attached to the side edge of the rebar cage 10a. 20c contacts and regulates the movement of the rebar cage 10a, so that accurate positioning can be achieved.

When suspending the positioned reinforcing cage 10a in the excavation hole 14a, the edge (corner) of the reinforcing cage 10a contacts the inner surface of the beam 20a, and
The guide piece 20c comes into contact with the side edge of the reinforcing rod cage 10c.
In the state a, two sides are restrained, the state of the rebar basket 10a is stabilized, and the installation accuracy is further improved.

[0023]

FIG. 4 shows a third embodiment of the method for building a reinforcing rod cage according to the present invention. The same or corresponding parts as those in the above embodiment are denoted by the same reference numerals and description thereof is omitted. In addition, only the characteristic points will be described below. In the embodiment shown in the figure, the embedding method of the present invention is applied to the case where the underground continuous wall 12a is formed in a straight line like the second embodiment.

A pair of guide members 20 "fixed on the excavation hole 14a when the reinforcing rod cage 10a is built,
An L-shaped stopper 20d is provided corresponding to the position where a longitudinal edge (corner) of the is abutted on the beam 20a. Even with the use of the guide member 20 ″ configured as described above, the same operation and effect as those of the above embodiment can be obtained.

[0025]

As described above in detail in the embodiments,
According to the method for installing a reinforcing cage in the underground continuous wall method according to the present invention, the guide member is fixed in a C-shape on the excavation hole, so that the mounting accuracy of the reinforcing cage can be relatively easily operated. Can be secured.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view showing a first embodiment of a method for installing a reinforcing bar cage according to the present invention.

FIG. 2 is an explanatory side view of FIG. 1;

FIG. 3 is an explanatory plan view showing a second embodiment of the method for installing a reinforcing bar cage according to the present invention.

FIG. 4 is an explanatory plan view showing a third embodiment of the method for installing a reinforcing bar cage according to the present invention.

[Explanation of symbols]

 10, 10a Reinforced basket 12, 12a Underground continuous wall 14, 14a Excavation hole 16, 16a Leading wall 18, 18a Trailing wall 20, 20 ', 20 "Guide member 20a Beam 20b Mounting plate 20c Guide piece 20d Stopper 22 Guide Wall 26 Marking Display

Claims (3)

(57) [Claims] 1. An underground continuous wall method in which a steel cage is erected in a grooved excavation hole excavated in the ground, and then concrete is cast and a panel-like wall body is sequentially connected and formed. When the cage is built in the excavation hole, a pair of positioning guide members arranged in a C-shape are fixed on the excavation hole, and the lower end side of the reinforced cage suspended and supported from the enlarged interval side. Inserted between the guide members, and moved in parallel to the reduction interval side to a position where both longitudinal edges of the reinforcing bar abut against the inner surface of the guide member, and thereafter, while maintaining the abutting state, the reinforcing cage is A method for installing a reinforcing bar in an underground continuous wall method, wherein the reinforcing bar is installed in the excavation hole. 2. The method according to claim 1, wherein the positioning guide member is provided with a marking corresponding to the contact position. 3. The grounding member according to claim 1, wherein the positioning guide member is provided with a guide piece that comes into contact with a side edge of the rebar cage on the enlarged interval side of the contact position. Construction method of reinforced cage in medium wall construction method.