JP2021001453A - Top plate construction method of vertical shaft and top plate structure - Google Patents

Abstract

To efficiently construct a top plate 9 that closes a ground surface side opening of a vertical shaft 1.SOLUTION: When constructing a vertical shaft 1, a first member 11 and a second member 12 are fixed to upper ends of steel piles 3A and 3B installed in facing wall bodies 2A and 2B, respectively. When constructing a top plate 9, a third member 13 (13-1 to 13-3) is installed between the first member 11 and the second member 12, and these are connected. Then, at least the third member 13 is used as an embedded formwork, and concrete (14) is cast on it. At least the third member 13 is a steel frame embedded panel, and includes a plate-shaped precast concrete 21 and a steel frame 22 arranged in parallel on it and having a lower cross section embedded in the precast concrete 21. The first member 11 and the third member 13, and the second member 12 and the third member 13 are connected by joining the steel frames of each other.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for constructing a top plate that closes an opening on the ground side of a shaft (vertical skeleton) and its structure. The "top plate" referred to in the present invention is a case of being viewed from the underground side of the shaft, and can also be referred to as a "floor plate" when viewed from the ground side.

In the construction of shield tunnels in urban areas, a shaft will be installed, and a shield excavator will be introduced through the opening of the shaft, after which the opening of the shaft will be used to bring in materials and equipment. In addition to such starting shafts, there are also reaching shafts and intermediate shafts as shafts for tunnel construction. Then, after the tunnel construction is completed, the opening of the shaft is closed by the top plate, and the underground side and the above-ground side can be used respectively.

Patent Document 1 discloses a construction procedure of a shield tunnel including construction of a shaft skeleton. Furthermore, after the construction of the tunnel is completed, as the construction work inside the shaft, the floor slabs and columns should be constructed while accumulating the formwork support works in order from the bottom to the top inside the shaft, and the formwork support works should be removed after the concrete strength is developed. Is disclosed.

Further, in Patent Document 2, as a method of constructing a middle floor slab of an underground structure, a formwork support is constructed on the lower floor, a middle floor slab formwork is installed on the formwork, and concrete is placed on the formwork. Then, a method of constructing a midfloor slab is disclosed.

JP-A-2017-203294 Japanese Unexamined Patent Publication No. 2002-371570

When constructing a top plate that closes the above-ground opening of a shaft (vertical skeleton), the method of providing formwork support from the lower side as shown in Patent Documents 1 and 2 has the following problems.
If the height to the top plate to be constructed is high and the opening area is large, scaffolding and support work will be large, and a large amount of materials and construction work will be required for these installations.
In addition, after the top plate is constructed, the opening is closed, so the support work cannot be lifted from the ground side and removed, and it will be dismantled and removed from the limited small opening. Removal can be very tedious.

In view of such an actual situation, the present invention makes it possible to simplify the work of constructing the top plate and the work after constructing the top plate when constructing the top plate that closes the above-ground opening of the shaft (vertical shaft frame). The task is to do.

The method for constructing a top plate of a shaft according to the present invention is as follows.
At the time of constructing the shaft, the first member protruding in the opposite direction is fixed in advance to the upper end of the steel pile installed in one of the wall bodies facing each other across the above-ground opening of the shaft. A preliminary step of preliminarily fixing the second member protruding in the opposite direction to the upper end of the steel pile installed in the other wall.
At the time of constructing the top plate, a third member is installed between the first member and the second member, and a bridging process of connecting them is performed.
The process of placing concrete on the third member as an embedded formwork,
Including
The first member and the second member include a steel frame and include a steel frame.
The third member is arranged on the plate-shaped precast concrete and the precast concrete, extends in the longitudinal direction of the precast concrete, the lower part of the cross section is embedded in the precast concrete, and the upper part of the cross section is the precast concrete. Is a steel-embedded panel, including a steel frame exposed above
The bridging step is characterized in that the first member and the third member, and the second member and the third member are connected to each other by steel frames.

Further, the top plate structure of the shaft according to the present invention is
Of the wall bodies facing each other across the above-ground opening of the shaft, a first member fixed to the upper end of a steel pile installed in one of the walls and protruding in the opposite direction,
A second member fixed to the upper end of a steel pile installed in the other wall and protruding in the opposite direction,
A third member installed between the first member and the second member and connected to the third member
Using the third member as an embedded formwork, a concrete layer cast on the third member and
Including
The first member and the second member include a steel frame and include a steel frame.
The third member is arranged on the plate-shaped precast concrete and the precast concrete, extends in the longitudinal direction of the precast concrete, the lower part of the cross section is embedded in the precast concrete, and the upper part of the cross section is the precast concrete. Is a steel-embedded panel, including a steel frame exposed above
The first member and the third member, and the second member and the third member are connected to each other by steel frames.

According to the present invention, the first member (or the second member) installed in advance on the wall body side is used to connect the first member (or the second member) and the third member to perform the top. The efficiency of plate erection work can be improved. This eliminates the need to install large-scale scaffolding and support works inside the shaft, and dismantle and remove them after the top plate is constructed, which simplifies the construction work of the top plate and the work after construction.
In addition, by using the steel frame embedded panel as the formwork for the top plate, it is not necessary to install the formwork or dismantle and remove it.
Further, by using the steel frame embedded panel, the amount of bar arrangement at the site (and the labor for bar arrangement) can be reduced as much as possible.

The figure which shows the construction example of the top plate of the shaft as one Embodiment of this invention. Diagram showing the procedure for building the top plate Side view of the steel frame embedded panel that doubles as a formwork for building the top plate Enlarged view of the main part of the steel frame embedded panel as above Cross-sectional view of one unit of the steel frame embedded panel corresponding to the VV cross section of FIG. Cross-sectional view of the same steel frame embedded panel connected between adjacent units The figure which shows the connection structure (1) of a steel frame embedded panel and a side wall body. The figure which shows the connecting structure (2-1) of a steel frame embedded panel and a side wall body. The figure which shows the connecting structure (2-2) of a steel frame embedded panel and a side wall body. The figure which shows the connection structure (3) of a steel frame embedded panel and a side wall body.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 shows an example of constructing a top plate that closes the above-ground opening of a shaft as an embodiment of the present invention.

The shaft 1 of this example is a shaft having a rectangular shape in a plan view for shield tunnel construction, and is constructed as follows, for example.
For example, by the SMW (Soil Mixing Wall) method, a pillar-row type mountain retaining wall 2 surrounding all four sides is constructed from the ground G to the ground, and inside the wall, from H-shaped steel or square steel pipe at predetermined intervals. Build a steel pile.

When constructing the mountain retaining wall 2, an underground continuous wall construction method may be adopted. In this case, for example, a box-shaped steel member which is a ready-made steel continuous wall is built. Such a steel wall can also be used as a steel pile.

After the construction of the mountain retaining wall 2, the inside of the rectangular opening surrounded on all sides by the mountain retaining wall 2 is excavated, and the bottom slab 4 made of RC (reinforced concrete) is constructed on the floor surface, and the mountain retaining wall 2 is constructed. Similarly, by constructing an RC side wall 5 on the inner surface, a bottomed rectangular tubular shaft skeleton 7 is constructed.

Further, the shaft 1 of this example is a starting shaft for shield tunnel construction, and is used for carrying in a shield machine. The shield tunnel 8 is constructed by digging horizontally from the bottom of the shaft 1 with the shield machine. During the construction of the shield tunnel 8, the shaft 1 is used for carrying in various materials and equipment (segments, etc.) and carrying out excavated earth and sand. However, the shaft is not limited to the starting shaft, and may be an reaching shaft or an intermediate shaft.

In this example, after the shield tunnel 8 is completed, the top plate 9 is constructed in the above-ground opening of the shaft 1 (vertical skeleton 7) so as to block the shield tunnel 8. This is because it can be used as a park or the like by embankment on the top plate 9 on the ground side of the shaft 1. In addition, the shaft space below the top plate 9 can be used as an emergency staircase or a utility tunnel (power wire, water supply / drainage pipe, ventilation port). The entire surface of the above-ground opening of the shaft 1 is not necessarily closed by the top plate 9, and at least a part of the opening is closed.

The construction method of the top plate 9 will be described below.
First, it will be schematically described with reference to FIGS. 2 and 3.

FIG. 2 shows a procedure for constructing the top plate 9 using a steel frame embedded panel that also serves as a formwork for constructing the top plate. Further, FIG. 3 is a side view of the steel frame embedded panel. In the present embodiment, the steel frame embedded panel is composed of the first member 11, the second member 12, and the third member 13 (all are beam members).

FIG. 2A shows a preliminary process, which is carried out when the shaft 1 is constructed.
In the preliminary step, as shown in FIG. 2A, the piles are installed in one of the wall bodies (here, the mountain retaining walls 2A and 2B) facing each other across the above-ground opening of the shaft 1. The first member 11 projecting in the opposite direction is fixed in advance to the upper end portion of the steel pile 3A (FIG. 3), and the upper end of the steel pile 3B (FIG. 3) installed in the other wall body 2B. The second member 12 projecting in the opposite direction is fixed to the portion in advance.

Here, as shown in FIG. 3, the steel pile 3A and the first member 11 fix each other's steel frames to each other via a splicing plate 31 or the like. Further, the steel pile 3B and the second member 12 fix each other's steel frames to each other via a splicing plate 32 or the like. It should be noted that the steel frames may be fixed to each other by welding instead of using a splicing plate.

By installing the first member 11 and the second member 12 on the steel piles 3A and 3B, respectively, in the preliminary process, these project into the shaft 1 from the wall body side. For example, the wall body 2A, It may fit in the plane of 2B, or it may project to the opening side from the wall bodies 2A and 2B. In any case, by setting the overhang length from the steel piles 3A and 3B to about several hundred mm, the material can be brought into the shaft opening to the extent that it is not affected.

FIGS. 2 (b) and 2 (c) show the crossing process, which is carried out at the time of construction of the top plate 9 after the loading and unloading of main materials and equipment such as the shield machine is completed through the above-ground opening of the shaft 1. The main materials and equipment correspond to shield excavators in shield tunnel construction and segments that make up the lining of shield tunnels.
In the bridging step, as shown in FIGS. 2 (b) and 2 (c), a third member 13 is installed between the first member 11 and the second member 12, and these are connected.

In particular, in the present embodiment, the third member 13 is divided into three, that is, the left and right ends 13-1 and 13-2 in the bridging direction and the central member 13-3. The number of divisions of the third member 13 is not limited to this, and can be increased or decreased according to the length of the shaft opening in the girder direction (the length of the steel frame 22 in the extending direction).

Therefore, first, as shown in FIG. 2B, the third left end member 13-1 is connected to the first member 11 in a cantilevered state, and similarly, the third right end member 13-2 is connected to the second member 12. Connect in a cantilevered state.

Here, as shown in FIG. 3, the first member 11 and the third left end member 13-1 fix each other's steel frames to each other via a splicing plate 33 or the like, and the second member 12 and the third right end member 13 With -2, the steel frames of each other are fixed to each other via a splicing plate 34 or the like. The steel frames may be directly connected to each other by bolts and nuts without using splicing plates 33, 34 or the like.

Next, as shown in FIG. 2C, a third central member 13-3 is installed between the third left end member 13-1 and the third right end member 13-2, and these are connected.

Here, as shown in FIG. 3, the third left end member 13-1 and the third central member 13-3 fix each other's steel frames to each other via a splicing plate 35 or the like, and the third right end member 13-2. And the third central member 13-3 fix each other's steel frames to each other via a splicing plate 36 or the like. The steel frames may be directly connected to each other by bolts and nuts without using splicing plates 35, 36 or the like.

FIG. 2D shows a concrete placing process, which is carried out after the laying process.
In the concrete placing step, as shown in FIG. 2D, at least the third member 13 (13-1 to 13-3), particularly in the present embodiment, the first to third members 11 to 13 are used as the buried formwork. , Concrete is poured on these. In addition, necessary reinforcement may be arranged on the buried formwork before casting. As a result, the concrete layer 14 is formed on the first to third members 11 to 13, and the top plate 9 is constructed.

Next, regarding the structures of the first member 11, the second member 12, and the third member 13 (third left end member 13-1, third right end member 13-2, and third central member 13-3). This will be described with reference to FIGS. 3 and 4 to 6.

FIG. 4 is an enlarged view of a main part of the steel frame embedded panel of FIG. 3, FIG. 5 is a sectional view of one unit of the steel frame embedded panel corresponding to the VV cross section of FIG. 4, and FIG. 6 is a cross-sectional view of one unit of the steel frame embedded panel adjacent to each other. It is sectional drawing of the state connected by.

In the present embodiment, the steel frame embedded panel is composed of the first to third members 11 to 13.
In the present embodiment, the first to third members 11 to 13 are steel frame embedded panels, respectively, and the first to third members 11 to 13 (first member 11, third member 13 in order from the first member 11 side). , Second members 12) are connected in these longitudinal directions to form one large steel embedded panel.

Further, the third member 13 in the present embodiment is divided into three, and more specifically, in order from the first member 11 side, the first member 11, the third left end member 13-1, and the third central member 13- 3. The third right end member 13-2 and the second member 12 are connected in the longitudinal direction to form one steel frame embedded panel.

Next, the structure of the steel frame embedded panel will be described with reference to FIGS. 4 and 5.
The steel frame embedded panel includes a plate-shaped precast concrete 21 and a steel frame 22 arranged on the precast concrete 21 and extending in the longitudinal direction of the precast concrete 21.

Here, the lower part of the cross section of the steel frame 22 is embedded in the precast concrete 21, and the upper part of the cross section is exposed above the precast concrete 21.
As the steel frame 22, for example, H-shaped steel or I-shaped steel is used, one of these flanges is embedded in the precast concrete 21, and the other flange and the web (most of them) are on the precast concrete 21. Exposed to. As shown in FIG. 5, a plurality of steel frames 22 in the steel frame embedded panel may be arranged in parallel. By embedding and integrating a plurality of steel frames 22 in one precast concrete 21, the strength of the member as a formwork can be further increased.

As shown in FIG. 5, the steel frame 22 in the steel frame embedding panel is a large number (upper and lower two rows) of small steel materials (small beams) protruding in a direction orthogonal to the extending direction of the steel frame 22 because the adjacent steel frames 22 are connected to each other. It has a steel frame) 23 (23A, 23B). The small steel materials 23 (23A, 23B) can be made of a small H-shaped steel or I-shaped steel that is welded and fixed to the web portion of the large H-shaped steel or I-shaped steel that constitutes the steel frame 22.

The steel frame embedded panel is divided into the first to third members 11 to 13 in the extending direction of the steel frame 22, and is also divided in the direction orthogonal to the extending direction of the steel frame 22 in the unit shown in FIG. , It is unitized.

The panel unit (1 unit of the steel frame embedded panel) shown in FIG. 5 is formed by projecting inward from the two steel frames 22 and the two steel frames 22 whose lower cross sections are embedded by the precast concrete 21, and using a splicing plate 24 or the like. It is composed of an inner small steel material 23A connected to each other and an outer small steel material 23B protruding outward from each of the two steel frames 22. Such a panel unit is manufactured before the laying process, for example, manufactured in a factory, and brought to the site.

FIG. 6 shows a state in which the panel units of FIG. 5 are connected between adjacent units. The connection between the units is performed by arranging the outer small steel material 23B and the connecting material 25 having the same cross-sectional shape in between.
That is, in the bridging step, the outer small steel members 23B of the adjacent panel units are connected to each other via, for example, a splicing plate 26 after arranging the connecting member 25 between them. It should be noted that joints may be used for connection regardless of the splicing plate 26 or the like. The connection here is made after the laying process and before the concrete placing process.

In the present embodiment, in order to facilitate the connection work at the site, the tip of the outer small steel material 23B is slanted to form a space that opens upward (wide) between the outer small steel materials 23B, and the space is reversed. The triangular (or inverted trapezoidal) connecting member 25 can be easily inserted from above. The angle of the tip is not limited and may be vertical as is normally done.

In FIG. 6, the gap between the units is exaggerated, but this is for clarifying the unit of the unit, and the gap is actually joined so as to be within a predetermined design dimension. Further, each joint portion of the precast concrete 21 in the unit may be used as a key type so that the joint cross section has a notched joint shape.

Next, a method of constructing the top plate 9 using the steel frame embedded panel as described above will be described in more detail with reference to FIGS. 4 to 6 according to the construction procedure of FIG.

In the preliminary step corresponding to FIG. 2A, of the wall bodies (here, mountain retaining walls 2A and 2B) facing each other across the above-ground opening of the shaft 1 when the shaft 1 (vertical frame 7) is constructed. The first member 11 (the steel frame 22 thereof) is fixed to the upper end of the steel pile 3A installed in the one wall 2A by using a splicing plate 31 or the like or welding all around. Similarly, the second member 12 (the steel frame 22 thereof) is fixed to the upper end of the steel pile 3B installed in the other wall body 2B.

The first member 11 (and the second member 12) is unitized in a direction orthogonal to the bridging direction in units of two steel frames, and the outer small steel members 23B are connected to each other with the connecting member 25 between the units. It is connected via a contact plate 26 or the like, but it does not necessarily have to be unitized.

In the crossing process at the time of constructing the top plate corresponding to FIGS. 2 (b) and 2 (c), the third left end member 13-1 is lifted by a lifting machine such as a crane and carried on the extension of the first member 11 to carry the first member 11. The 1st member 11 and the 3rd left end member 13-1 are connected and fixed via a splicing plate 33 or the like. At this time, the third left end member 13-1 is in a cantilever state.
Such a connecting operation can be performed by using the precast concrete 21 of the first member 11 as a scaffold, that is, a worker riding on the precast concrete 21 on the wall side. Further, you may work by installing a scaffolding overhanging from the wall body 2A. The connection between the second member 12 and the third right end member 13-2 can be performed in the same manner.

Further, the third left end member 13-1 and the third right end member 13-2 are unitized in the direction orthogonal to the bridging direction in units of two steel frames, and the outer small steel material 23B is used between the units. They are connected to each other via a connecting member 25, a splicing plate 26, and the like. This work can be carried out using the precast concrete 21 of the third left end member 13-1 and the third right end member 13-2 as scaffolding, respectively.

Next, the third central member 13-3 is lifted by a lifting machine such as a crane and carried between the third left end member 13-1 and the third right end member 13-2, and the third left end member 13-1 and the first 3 The central member 13-3 is connected and fixed via a splicing plate 35 or the like.
Such connecting work can be performed by using the precast concrete 21 of the third left end member 13-1 as a scaffold, that is, a worker riding on the precast concrete 21 on the wall side.

Similarly, the third right end member 13-2 and the third central member 13-3 are connected and fixed via the splicing plate 36 and the like.
Such a connecting operation can be performed by using the precast concrete 21 of the third right end member 13-2 as a scaffold, that is, a worker riding on the precast concrete 21 on the wall side.

Further, the third central member 13-3 is also unitized with two steel frames as a unit in the direction orthogonal to the bridging direction, like the third left end member 13-1 and the third right end member 13-2. The outer small steel materials 23B are connected to each other by using the connecting material 25 and the splicing plate 26 between the units. This work can be carried out using the precast concrete 21 of the third central member 13-3 as a scaffold.

Here, as can be seen from FIG. 3 or FIG. 4, the joint portion (divided portion) of the first to third members 11 to 13 (13 to 1 to 3) may be formed at an oblique tip. This is to facilitate insertion and joining when the member (post-insertion member) to be joined to the member on the wall body side is suspended and joined. For example, when the third central member 13-3 is inserted, if the receiving side (between the third left end member 13-1 and the third right end member 13-2) has an inverted C shape, the insertion and joining are performed. It will be easier to remove. At this time, the splicing plates 33 to 36 may be formed in a parallelogram shape according to the angle of the tip portion.

In the concrete placing step corresponding to FIG. 2D, the first to third members 11 to 13 are used as buried formwork, and concrete is placed on them. As a result, the concrete layer 14 is formed on the first to third members 11 to 13, and the top plate 9 is constructed.

In the concrete placing process, reinforcing bars may be arranged on the formwork prior to the concrete placing. Such bar arrangement work can be performed using the precast concrete 21 of the first to third members 11 to 13 as a scaffold. By performing the bar arrangement work after the laying process and before the concrete placement, the reinforcing bars and the steel frame embedded panel are integrated with the concrete after the concrete placement, and a strong top plate is constructed.
Further, by using the steel frame embedded panel as the buried formwork, there is an advantage that the bar cross-sectional integral that should be originally laid is handled by the cross-sectional area of the steel frame, and the amount of bar arranging (and the labor for arranging the reinforcing bars) can be simplified.

Since the steel frame embedded panel is divided in the longitudinal direction and unitized in the width direction, a gap (joint due to division or the like) is generated between the divided bodies and between the units. Therefore, prior to placing concrete, this gap is closed with a sealant and / or caulking treatment. In addition, the part where the gap becomes large may be closed by a steel plate.

Not only the connection between the steel embedded panel and the wall body in the girder direction, but also the connection with the wall body in the direction orthogonal to the girder direction is necessary to close the rectangular opening. Connection of a wall body (or pile body) orthogonal to the wall bodies (mountain retaining walls 2A and 2B) on the mounting side of the first and second members 11 and 12 and a top plate (side surface along the extending direction of the steel frame). That is, with respect to the connecting portion between the wall body (or pile body) and the first member 11, the second member 12 and the third member 13, the wall body (pile body) is a concrete wall or an RC pile (a portion not made of steel). ), The method (1) below, and if it is a steel wall or a steel pile, the method (2) or (3) below. At this time, the method (3) is preferable and the method (1) or (2) is selected when stress transmission as a structure is expected even in the connection connection with the wall body in the direction orthogonal to the girder direction. In the case, the purpose is merely to integrate the wall body and the top plate as members.

(1) As shown in FIG. 7, a post-construction anchor 101 is driven into an RC pile 3C constituting a wall body (mountain retaining wall) 2C in a direction orthogonal to the girder direction, or an insert pre-embedded in the RC pile. To be integrated with the concrete placed in the concrete placing process.

(2) As shown in FIG. 8, the stud 102 is welded on-site to the steel pile 3C constituting the wall body (mountain retaining wall) 2C in the direction orthogonal to the girder direction, or as shown in FIG. , The coupler 103A is welded to the steel pile 3C in advance at the factory, and the reinforcing bar 103B is screwed in at the site. Then, these are integrated with the concrete placed in the concrete placing process.

(3) As shown in FIG. 10, the steel beam 104 is projected from the steel pile 3C constituting the wall body (mountain retaining wall) 2C in the direction orthogonal to the girder direction in advance by welding or the like, and the steel frame embedded panel side. After arranging the connecting member 105 with the small steel material 23B of the above, the connecting member 105 is connected via, for example, a splicing plate 106 or the like. Then, these are integrated with the concrete placed in the concrete placing process.
As shown in FIGS. 7 to 10, in the gap between the wall body in the direction intersecting the girder direction and the steel frame embedded panel, a filling type made of a steel plate or the like is provided prior to placing concrete. The frame 110 is arranged.

Even if the concrete wall part with exposed concrete and the steel wall part with exposed steel material are partially present in the wall body in the direction orthogonal to the girder direction, the post-construction anchor and insert are provided in the concrete wall part. It is preferable to install any of the above, such as studs, couplers, and steel beams in the steel wall portion, before the concrete placing process. At this time, the projected post-construction anchor, insert, stud, coupler, steel beam, etc. are interconnected with the small steel material 23B on the steel frame 22 side of each of the first member 11, the second member 12, and the third member 13. Alternatively, they may be installed so as to overlap each other in a plan view and an elevation view.

According to the present embodiment, the first and second members 11 and 12 on the wall body side and the third member 13 installed between them are arranged on the plate-shaped precast concrete 21 and the precast concrete 21. A steel frame embedding panel including a steel frame 22 extending in the longitudinal direction of the precast concrete 21 and having a lower part of the cross section embedded in the precast concrete 21 and an upper part of the cross section exposed above the precast concrete 21 is 3 in the longitudinal direction thereof. The first member 11 and the third member 13, and the second member 12 and the third member 13 are connected to each other by steel frames.

As a result, the first member 11 (or the second member 12) on the wall side can be used as a scaffold to connect the first member 11 (or the second member 12) and the third member 13, and after the connection, the connection work can be performed. , Reinforcing work and the like can be performed using the first to third members 11 to 13 as scaffolding. Therefore, it is possible to eliminate large-scale temporary construction such as total scaffolding and support work from the shaft bottom slab. Further, by using the steel frame embedded panel, the amount of on-site reinforcement (and the labor for reinforcement) can be reduced as much as possible.

Further, according to the present embodiment, the first to third members 11 to 13 are used as the embedded formwork, and concrete is cast on them, but by using the steel frame embedded panel as the formwork of the top plate 9. , Installation of formwork and dismantling and removal work are also unnecessary.

Further, according to the present embodiment, the third member 13 is further divided into three in the longitudinal direction, and these divided bodies 13 to 1 to 3 are also connected to each other by steel frames. By adopting such a divided form, it is possible to carry the product from the factory to the site and to fit the size so that it can be easily handled at the site. In other words, it is possible to avoid restrictions on public road transportation (limitations on length and width due to road traffic law regulations) and restrictions on member weight (when the member weight becomes heavier, a lifting machine with excessive specifications is required). Further, by increasing the number of divisions of the third member 13, it is possible to cope with a large span of the shaft opening. However, even when increasing the number of divisions of the third member 13, it is desirable to avoid division at the central portion where the bending moment is maximum and to set the number of divisions to an odd number (for example, five).

Further, according to the present embodiment, when the third member 13 is divided into three parts, the precast concrete 21 of the member on the wall body side is used as a scaffolding to perform the connecting work in order from the wall body side (so-called one-sided push construction). Therefore, there is no need for large-scale temporary construction such as total scaffolding and support work from the shaft bottom slab.

Further, according to the present embodiment, the steel frame 22 in the steel frame embedded panel has a small steel material 23 protruding in a direction orthogonal to the extending direction thereof, and the adjacent steel frames 22 are joined to each other by the small steel materials 23. ..
As a result, the strength of the steel frame embedded panel in the direction orthogonal to the steel frame extending direction (force distribution direction) can be improved. In addition, by taking charge of the cross-sectional integration of the reinforcing bars in the force distribution direction that should be originally arranged by the cross-sectional area of the small steel material 23, the amount of on-site reinforcement arrangement (and the labor for reinforcement arrangement) can be further reduced in the force distribution direction, and labor saving Can also contribute to.

Further, according to the present embodiment, the steel frame embedded panel is divided into units in a direction orthogonal to the extending direction of the steel frames for each of a plurality of steel frames (two in this example) arranged in parallel. .. By making such a unit, the total number of members can be reduced, the efficiency of carrying from the factory to the site can be improved, and the lifting time and effort when the members are hung by a crane or the like can be reduced. In the unit, the steel frame 22 is connected via the inner small steel material 23A, whereby sufficient strength can be secured.

Further, according to the present embodiment, the steel frame 22 in the steel frame embedded panel has a small steel material 23 protruding in a direction orthogonal to the extending direction thereof, and the outer small steel materials 23B of the adjacent panel units are connected to each other in the bridging process. To concatenate. That is, at least the third member 13 includes a plurality of steel frame embedded panels (panel units) divided in a direction orthogonal to the bridging direction, and the steel frame 22 in each steel frame embedded panel (panel unit) has an extending direction thereof. It has a small steel material 23 protruding in a direction orthogonal to the above, and connects the outer small steel materials 23B of the adjacent steel frame embedded panels in the bridging step. As a result, the panel units can be reliably connected and integrated.

Next, other embodiments of the present invention will be described.
In the above embodiment, all of the first member 11, the second member 12, and the third member 13 are made of a steel frame embedded panel.
However, the first member 11 and the second member 12 may have only a steel frame without the precast concrete 21, and only the third member 13 (13-1 to 13-3) may be a steel frame embedded panel. ..

Also in this case, the first member 11 (or the second member 12) installed in advance on the wall body side is used to connect the first member 11 (or the second member 12) and the third member 13. Therefore, the efficiency of the top plate erection work can be improved. Further, after the third member 13 is connected, the work can be performed using the third member 13 as a scaffold. This also eliminates large-scale temporary construction such as total scaffolding and support work.

It should be noted that the illustrated embodiments merely illustrate the present invention, and the present invention is made by a person skilled in the art within the scope of claims in addition to the ones directly shown by the described embodiments. Needless to say, it includes improvements and changes in.

The present invention has an example of closing the above-ground opening of a shaft (vertical skeleton), but it can be widely deployed as long as it is a top plate that closes the upper end of an opposing wall body in the ground. ..

1 Vertical shaft 2 (2A, 2B) Mountain retaining wall 3 (3A, 3B) Steel pile 4 Bottom slab 5 Side wall 7 Vertical shaft skeleton 8 Shield tunnel 9 Top slab 11 1st member 12 2nd member 13 3rd member 13-1 3rd Left end member 13-2 Third right end member 13-3 Third center member 14 Concrete layer 21 Precast concrete 22 Steel frame (H-shaped steel or I-shaped steel)
23 (23A, 23B) Small steel material 24 Splicing plate 25 Connecting material 26 Splicing plate 31-36 Splicing plate 101 Post-construction anchor 102 Stud 103A Coupler 103B Reinforcing bar 104 Steel beam 105 Connecting material 106 Splicing plate 110 Filling formwork

Claims (6)

It is a method of constructing a top plate that closes the above-ground opening of the shaft.
When constructing the shaft, the first member protruding in the opposite direction is fixed in advance to the upper end of the steel pile installed in one of the wall bodies facing each other across the above-ground opening of the shaft. A preliminary step of preliminarily fixing the second member protruding in the opposite direction to the upper end of the steel pile installed in the other wall.
At the time of constructing the top plate, a third member is installed between the first member and the second member, and a bridging step of connecting them is performed.
The process of placing concrete on the third member as an embedded formwork,
Including
The first member and the second member include a steel frame and include a steel frame.
The third member is arranged on the plate-shaped precast concrete and the precast concrete, extends in the longitudinal direction of the precast concrete, the lower part of the cross section is embedded in the precast concrete, and the upper part of the cross section is the precast concrete. Is a steel-embedded panel, including a steel frame exposed above
The method for constructing a top plate of a shaft, which comprises connecting the first member and the third member, and the second member and the third member with each other in the steel frame. The first member and the second member are arranged on the plate-shaped precast concrete and the precast concrete, extend in the longitudinal direction of the precast concrete, the lower part of the cross section is embedded in the precast concrete, and the upper part of the cross section. The method for constructing a top plate of a shaft according to claim 1, wherein is a steel frame embedded panel including a steel frame exposed above the precast concrete. The bridging step is characterized in that the first member or the second member and the third member are connected to each other by using the precast concrete of the first member or the second member as a scaffold. The method for constructing a top plate of a shaft according to claim 2. The top of the shaft according to any one of claims 1 to 3, wherein the steel frame embedded panel constituting the third member includes a plurality of steel frames arranged in parallel on the precast concrete. How to build a version. The third member includes a plurality of steel frame embedded panels divided in a direction orthogonal to the bridging direction.
The steel frame in each steel frame embedded panel has a small steel material protruding in a direction orthogonal to the extending direction thereof.
The method for constructing a top plate of a shaft according to claim 4, wherein in the bridging step, small steel materials of adjacent steel frame embedded panels are connected to each other. It is a top plate structure that closes the above-ground opening of the shaft.
Of the wall bodies facing each other across the above-ground opening of the shaft, a first member fixed to the upper end of a steel pile installed in one of the walls and protruding in the opposite direction,
A second member fixed to the upper end of a steel pile installed in the other wall and protruding in the opposite direction,
A third member installed between the first member and the second member and connected to the third member
Using the third member as an embedded formwork, a concrete layer cast on the third member and
Including
The first member and the second member include a steel frame and include a steel frame.
The third member is arranged on the plate-shaped precast concrete and the precast concrete, extends in the longitudinal direction of the precast concrete, the lower part of the cross section is embedded in the precast concrete, and the upper part of the cross section is the precast concrete. Is a steel-embedded panel, including a steel frame exposed above
A top plate structure of a shaft, wherein the first member and the third member, and the second member and the third member are connected to each other by steel frames.