JP4630213B2 - Bottom plate form fixing structure - Google Patents

Description

  The present invention relates to a fixing structure of a bottom plate formwork provided so as to protrude to the wall surface of a shaft at the lower end portion of a centle for lining concrete placed with a gap on the wall surface of the shaft.

As a technique for providing a formwork on the wall surface of the excavated shaft and placing mortar, concrete, or the like between the formwork and the wall surface, one disclosed in Patent Document 1 is known. This technique comprises a plurality of molds comprising a panel body curved in an arc shape, a mortar guide plate bent in the center direction at the upper end of the panel body, and a bottom plate bent outward at the lower end of the panel body. A predetermined gap is formed between the frame panels and the wall surface of the shaft by assembling a cylindrical formwork by sequentially connecting the frame panels in the circumferential direction in the shaft.
Japanese Patent Laid-Open No. 11-200369

  However, the technique described in Patent Document 1 requires bending of the mortar guide plate and the bottom plate, which causes a problem of increasing the manufacturing cost of the mold. Therefore, for example, a relatively inexpensive wood plate material is used as a bottom plate and is applied to the lower end portion of the formwork, and this wood plate material is supported on the bottom plate of the shaft by a square material such as a flap angle, thereby reducing the manufacturing cost of the formwork. There was a request to reduce it.

However, after mortar or concrete is placed, when the excavation of the shaft is to be advanced further downward, the wooden board is only supported by squares such as butterfly corners. If the excavation work was started before it dried, it might peel off. For this reason, the excavation work of the shaft cannot be advanced until the placed mortar and concrete are completely dried, and the construction period may be prolonged.
In addition, in order to reliably support the wooden board on the bottom plate of the shaft, a large amount of flutter angle is required, so it takes time to install the wooden board and further delays the construction period.
Therefore, there is a development of a technology that can solve the above problems by firmly fixing a bottom plate (hereinafter referred to as a bottom plate mold frame) provided at the lower end of the mold frame to the mold frame (hereinafter referred to as a centle). It was desired.

  An object of the present invention is to provide a bottom plate mold frame fixing structure capable of firmly fixing a bottom plate mold frame and thereby shortening the construction period.

The invention according to claim 1, for example, as shown in FIGS. 1 and 2, is provided at the lower end portion of the centre 10 for placing concrete C placed on the wall surface 1 a of the shaft 1 with a predetermined gap S therebetween. In the fixing structure of the bottom plate mold 20 provided so as to protrude to the wall surface 1a of the shaft 1,
The centle 10 has a frame plate portion 11 facing the gap S at a lower end portion thereof, and a horizontal plate portion 12 provided horizontally at the lower end portion of the frame plate portion 11,
The bottom plate mold 20 is formed of a metal plate, is in contact with the lower surface of the horizontal plate portion 12, and is fixed to fix the bottom plate mold frame 20 and the horizontal plate portion 12 so as to be sandwiched therebetween. 30 and is fixed to the horizontal plate part 12 ;
The fixing bracket 30 includes a long portion 31a and a short portion 31b, and a main body portion 31 formed in an L shape in a side view, and one end of the short portion 31b parallel to the long portion 31a. An extension portion 32 extending a predetermined length,
When the bottom plate mold 20 is fixed to the horizontal plate portion 12 by the fixing bracket 30, the long portion 31a is located on the bottom plate mold 20 side, and the extending portion 32 is located on the horizontal plate portion 12 side. It is characterized by.

According to the first aspect of the present invention, the bottom plate mold can be firmly fixed to the horizontal plate portion by fixing the bottom plate mold frame and the horizontal plate portion so as to be sandwiched by the fixing metal fitting. Thus, unlike the conventional case, the bottom plate formwork will not be peeled off even if the shaft excavation work is carried out until the cast concrete is completely dried, so that the construction period can be shortened.
Then, when the cast concrete is dried, the bottom plate formwork can be easily separated from the horizontal plate by simply removing the fixing bracket when the centle is peeled off. Can be achieved.
Further, when the bottom plate mold is fixed to the horizontal plate portion by the fixing bracket, the long portion is located on the bottom plate mold side and the extension portion is located on the horizontal plate portion side. The bottom plate mold can be securely fixed to the horizontal plate by simply sandwiching the bottom plate mold and the horizontal plate between the extension portions.
In addition, since the bottom plate mold can be reliably fixed to the horizontal plate portion in this way, unlike the conventional case, the installation work of the bottom plate mold does not take time.
Further, since the fixing bracket is configured to sandwich the bottom plate formwork and the horizontal plate portion, the fixing bracket can be easily attached and removed, so that the construction period can be further shortened. Can be achieved.

According to a second aspect of the invention, for example, as shown in FIGS. 2 to 4, in fixing structure of the bottom plate mold 20 according to claim 1, the wall surface 1a of the pit 1,支保Industrial Materials 2 pit 1 Are attached along the vertical direction, and between the support materials 2 adjacent to each other in the vertical direction, a rod-shaped support material 3 that connects these support materials 2 is provided,
The bottom plate mold 20 is characterized in that a cutout portion 23 that engages with the support joint 3 is formed on an outer peripheral portion 20 a of the bottom plate mold 20.

According to invention of Claim 2 , since the notch part engaged with the said support joint is formed in the said baseplate formwork, By making this notch engage with the said support joint, Thus, accurate positioning can be performed when the bottom plate formwork is provided. Thus, unlike the conventional case, the installation work of the bottom plate formwork does not take time, and therefore the construction period can be further shortened.

According to the present invention, the bottom plate mold can be firmly fixed to the horizontal plate by fixing the metal plate forming the bottom plate and the horizontal plate by sandwiching the metal plate. Thus, unlike the conventional case, the bottom plate formwork will not be peeled off even if the shaft excavation work is carried out until the cast concrete is completely dried, so that the construction period can be shortened.
And, when the cast concrete is dried, when removing the centle, the bottom plate mold can be easily separated from the horizontal plate by simply removing the fixing bracket, further shortening the construction period. Can be planned.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an example of a fixing structure of a bottom plate mold 20 according to the present invention. The shaft 1 shown in this figure is excavated in a cylindrical shape by a shaft excavator (not shown). The vertical shaft 1 according to the present embodiment performs excavation at a predetermined depth according to the condition of the natural ground, immediately places the primary lining concrete C, and further advances the excavation while repeating the reinforcement of the natural ground. After that, the conventional short step method of performing secondary lining is constructed. In the present embodiment, a structure for fixing the bottom plate formwork 20 when performing secondary lining will be described.

  Here, the shaft 1 is provided with a centle 10 which is a formwork for placing concrete lining C with a predetermined gap S in the wall surface 1 a of the shaft 1. And this centle 10 is formed in the cylindrical shape so that the circumferential direction of the shaft 1 may be followed at the time of installation.

  Further, as shown in FIG. 2, the centle 10 has, at its lower end, a frame plate portion 11 facing the gap S and a horizontal plate portion 12 provided horizontally at the lower end portion of the frame plate portion 11. Have. Further, a reinforcing plate portion 13 is provided so as to be adjacent to the frame plate portion 11, and the frame plate portion 11 and the reinforcing plate portion 13 are provided so as to be adjacent to each other, and a horizontal plate portion is provided at a lower end portion thereof. By providing 12, the rigidity of the lower end portion of the centle 10 can be increased.

  A bottom plate mold 20 is brought into contact with the lower surface of the horizontal plate portion 12, and the bottom plate mold 20 and the horizontal plate portion 12 sandwich the bottom plate mold 20 and the horizontal plate portion 12. It is sandwiched between fixing metal fittings 30 to be fixed. That is, the bottom plate mold 20 is sandwiched between the fixing brackets 30 and fixed to the horizontal plate portion 12.

Next, each part structure in this Embodiment is demonstrated in detail.
As shown in FIG. 2, a plurality of supporting materials 2 for earth retaining are attached to the wall surface 1 a of the shaft 1 along the vertical direction of the shaft 1. Thereby, the earth retaining of the inside of the shaft 1 can be performed reliably, and work can be advanced safely.
And between the support materials 2 adjacent to the upper and lower sides, the rod-shaped support material 3 which connects these support materials 2 is provided.

The bottom plate mold 20 is formed of a metal plate and is configured to form a circle along the circumferential direction of the shaft 1 by connecting a plurality of bottom plate mold materials 21, 22 as shown in FIG. It has become. In addition, the bottom plate mold 20 has an outer peripheral portion 20a and an inner peripheral portion 20b.
That is, as shown in FIG. 3 and FIG. 4, the first bottom plate frame member 21 having an arc shape and having an outer peripheral portion 21 a longer than the inner peripheral portion 21 b is also arc-shaped and has an inner peripheral portion 22 b. Are alternately connected to the second bottom plate mold material 22 which is longer than the outer peripheral portion 22a and smaller than the first bottom plate mold material 21, whereby the circular bottom plate mold 20 is formed. The

  In addition, a cutout portion 23 that engages with the support joint 3 is formed in the outer peripheral portion 21 a of the first bottom plate frame material 21. That is, by engaging the notch 23 with the support joint 3, it is possible to perform accurate positioning when the bottom plate mold 20 is provided, so that it takes time to install the bottom plate mold 20. Therefore, the construction period can be shortened.

  Further, handles 24 and 25 are attached to the inner peripheral portion of the first bottom plate mold frame material 21 and the inner peripheral portion of the second bottom plate mold frame material 22, and the first bottom plate mold frame material 21 and the second It is easy to use when attaching or removing the bottom plate formwork material 22. In addition, when the first bottom plate mold frame material 21 and the second bottom plate mold frame material 22 are suspended or lifted inside the shaft 1, a wire, a rope, or the like can be tied to the handles 24, 25. In addition, it is easy to use.

  The bottom plate mold 20 is a steel plate, and is firmly fixed to the horizontal plate portion 12 so that the bottom plate of the shaft 1 can be lowered even when the bottom plate of the shaft 1 is at a position significantly lower than the installation position of the bottom plate mold 20. There is no need to support from. Even in the case of supporting in an auxiliary manner, it is only necessary to provide a support member (not shown) at a key point.

  Further, a release agent (not shown) is applied in advance to the surface of the bottom plate formwork 20. Accordingly, after the concrete C is dried, the bottom plate mold 20 can be easily peeled off, and the removed bottom plate mold 20 is not damaged and can be used repeatedly.

On the other hand, the fixing bracket 30 is a steel material, and as shown in FIGS. 1 and 2, the main body 31 is formed of a long portion 31a and a short portion 31b, and is formed in an L shape in a side view. An extending portion 32 extending in a predetermined length from one end of the short portion 31b is provided in parallel with the long portion 31a. When the bottom plate mold 20 is fixed to the horizontal plate portion 12 by the fixing bracket 30, the long portion 31a is positioned on the bottom plate mold 20 side, and the extending portion 32 is positioned on the horizontal plate portion 12 side. To fix.
That is, the bottom plate mold 20 can be securely fixed to the horizontal plate 12 by simply sandwiching the bottom plate mold 20 and the horizontal plate 12 between the long portion 31 a and the extension 32. It has become. In addition, since the bottom plate mold 20 can be reliably fixed to the horizontal plate portion 12 in this way, unlike the prior art, the installation work of the bottom plate mold 20 does not take time.

  Furthermore, since the fixing bracket 30 is configured so as to sandwich the bottom plate mold 20 and the horizontal plate portion 12 in this way, the attaching and removing operations of the fixing bracket 30 can be easily performed. Therefore, the construction period can be further shortened.

Next, a fixing method of the bottom plate formwork 20 and a construction method of the shaft 1 will be described.
First, a shaft 1 having a predetermined depth is formed by excavating a natural ground, and a centle 10 is installed with a predetermined gap S in the wall surface 1a of the shaft 1.
At this time, the bottom plate mold 20 is provided at the lower end of the centle 10. That is, the bottom plate mold 20 is brought into contact with the lower surface of the horizontal plate portion 12, and the bottom plate mold 20 and the horizontal plate portion 12 are sandwiched by the fixing bracket 30, so that the bottom plate mold frame 20 is attached to the horizontal plate portion 12. Fix it. Then, concrete C is placed in the gap S.

  The bottom plate formwork 20 may be placed on the bottom plate in advance before the installation of the centle 10 in accordance with the depth of the bottom plate of the shaft 1, and is provided at a predetermined position after the installation of the centle 10. Anyway. Further, when the bottom plate mold 20 is provided, the notch 23 formed in the outer peripheral portion 21 a of the first bottom plate mold 21 is provided to be engaged with the support joint 3.

Subsequently, while waiting for the concrete C placed in the gap S to dry, excavation of the shaft 1 is advanced by a predetermined depth further below the centle 10.
The concrete C placed in the gap S dries and the excavation of the shaft 1 proceeds by a predetermined depth, and then the center 10 is installed with a predetermined gap S in the wall surface 1a of the newly excavated shaft 1. Then, the bottom plate mold 20 is fixed to the horizontal plate portion 12 and concrete C is placed in the gap S. And it repeats work as mentioned above and advances construction of shaft 1.

According to the present embodiment, the bottom plate mold 20 is firmly fixed to the horizontal plate 12 by fixing the metal plate forming the bottom plate mold 20 and the horizontal plate 12 so as to be sandwiched by the fixing metal 30. be able to. As a result, unlike the conventional case, the bottom plate formwork 20 does not peel off even if the excavation work of the shaft 1 is advanced until the cast concrete C is completely dried, so that the construction period can be shortened. Become.
And, after the placed concrete C is dry, when performing the stripping work of the centle 10, the bottom plate mold 20 can be easily separated from the horizontal plate portion 12 simply by removing the fixing bracket 30. Furthermore, the construction period can be shortened.

It is a side view which shows an example of the fixing structure of the baseplate formwork of this invention. It is a principal part enlarged view of the fixing structure of the baseplate formwork shown in FIG. It is a top view which shows the whole baseplate formwork. (A) is a top view which shows a 1st bottom plate type | mold frame material, (b) is a top view which shows a 2nd bottom plate type | mold frame material.

Explanation of symbols

1 Vertical shaft 10 Centle 20 Bottom plate formwork 30 Fixing bracket

Claims (2)

In the fixing structure of the bottom plate formwork provided so as to protrude to the wall surface of the shaft, at the lower end portion of the centle for lining concrete placed with a predetermined gap on the wall surface of the shaft,
The centile has a frame plate portion facing the gap at a lower end portion thereof, and a horizontal plate portion provided horizontally at the lower end portion of the frame plate portion,
The bottom plate mold is formed of a metal plate, is in contact with the lower surface of the horizontal plate portion, and is sandwiched between fixing brackets that fix the bottom plate mold frame and the horizontal plate portion. , Fixed to the horizontal plate part ,
The fixing bracket is composed of a long portion and a short portion, and extends in a predetermined length from one end of the short portion in parallel with the main portion formed in an L shape in a side view. And an extending part to be
When the bottom plate mold is fixed to the horizontal plate portion by the fixing bracket, the long portion is positioned on the bottom plate mold side and the extending portion is positioned on the horizontal plate portion side. Fixed structure. A plurality of support materials are provided along the vertical direction of the shaft on the wall surface of the shaft, and a rod-shaped support material is provided between the support materials adjacent to each other in the vertical direction. And
The bottom plate mold frame fixing structure according to claim 1 , wherein the bottom plate mold frame is formed with a notch portion that engages with the support joint material at an outer peripheral portion of the bottom plate mold frame.

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