JP7213154B2 - Top slab construction method for shaft and top slab structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a construction method and structure of a top slab that closes an opening on the ground side of a shaft (shaft skeleton). The term "top slab" as used in the present invention refers to the case when viewed from the underground side of the vertical shaft, and can also be referred to as the "floor slab" when viewed from the ground side.

In shield tunnel construction in urban areas, a vertical shaft is constructed, the shield machine is put in through the opening of the vertical shaft, and the opening of the vertical shaft is used for bringing in materials and equipment. Vertical shafts for tunnel construction include such starting vertical shafts as well as arrival vertical shafts and intermediate vertical shafts. After the tunnel construction is completed, the opening of the vertical shaft is closed by the top slab, and the underground side and the aboveground side can be used.

Patent Literature 1 discloses a shield tunnel construction procedure including construction of a vertical shaft skeleton. Furthermore, after the construction of the tunnel is completed, as part of the construction work inside the shaft, the floor slabs and columns are built up in order from the bottom to the top with form shoring inside the pit, and the form shoring is removed after the strength of the concrete is achieved. is disclosed.

In addition, Patent Document 2 describes a method for constructing a middle floor slab for an underground structure, in which a form shoring is constructed on the lower floor, a middle floor slab formwork is installed above it, and concrete is poured on it. Thus, a method of constructing a mid-floor slab is disclosed.

JP 2017-203294 A Japanese Patent Application Laid-Open No. 2002-371570

When constructing a top slab that closes the ground-side opening of a shaft (shaft skeleton), the method of providing formwork shoring from below, as shown in Patent Documents 1 and 2, has the following problems.
If the height to the top slab to be constructed is high and the opening area is large, the scaffolding and shoring will be large-scale, and installation of these will require a large amount of materials and construction work.
In addition, after the top slab is constructed, the opening is blocked, so the shoring cannot be removed by lifting it from the ground side. Removal would be very troublesome.

In view of such a situation, the present invention is designed to simplify the construction work of the top slab and the work after constructing the top slab when constructing the top slab that closes the ground side opening of the shaft (shaft skeleton). The task is to

The method for constructing the top slab of a vertical shaft according to the present invention includes:
When constructing the shaft, the first member projecting in the opposite direction is fixed in advance to the upper end of the steel pile installed in one of the walls facing each other across the ground-side opening of the shaft. a preliminary step of preliminarily fixing the second member projecting in the opposite direction to the upper end of the steel pile installed in the other wall;
A bridging step of installing a third member between the first member and the second member and connecting them when constructing the top plate;
A step of placing concrete on the third member as an embedded formwork;
including
The first member , the second member , and the third member are each arranged on a plate-shaped precast concrete and the precast concrete, extending in the longitudinal direction of the precast concrete, and having a cross-sectional lower portion a steel frame embedded in the precast concrete, the upper part of the cross section of which is exposed above the precast concrete;
In the bridging step, the first member and the third member, and the second member and the third member are connected by mutual steel frames.

Moreover, the top plate structure of the shaft according to the present invention is
a first member fixed to the upper end of a steel pile installed in one of the walls facing each other across the ground-side opening of the vertical shaft and projecting in the facing 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 disposed between and connected to the first member and the second member;
a concrete layer placed on the third member as an embedded formwork;
including
The first member , the second member , and the third member are respectively arranged on a plate-shaped precast concrete and on the precast concrete, extend in the longitudinal direction of the precast concrete, and extend in the lower section of the section. is embedded in the precast concrete, and a steel frame whose cross-sectional upper part is exposed above the precast concrete,
The first member and the third member, and the second member and the third member are connected by mutual steel frames.

According to the present invention, the first member (or the second member) installed in advance on the wall side is used to perform the work of connecting the first member (or the second member) and the third member. Efficiency of plate installation work can be achieved. As a result, there is no need to install large-scale scaffolding or shoring inside the vertical shaft, or to dismantle and remove them after constructing the top slab, thereby simplifying the construction work of the top slab and the work after construction.
In addition, by using the steel embedded panel as the formwork for the top slab, there is no need to install or dismantle the formwork.
In addition, by using the steel-embedded panel, it is possible to reduce the on-site rebar arrangement amount (and rebar arrangement labor) as much as possible.

A diagram showing a construction example of the top slab of a vertical shaft as one embodiment of the present invention. Diagram showing the construction procedure of the top slab Side view of a steel embedded panel that doubles as a formwork for constructing the top slab Enlarged view of the main part of the same steel embedded panel Sectional view of one unit of the steel embedded panel corresponding to the VV section of Fig. 4 Sectional view of the same steel frame embedded panel connected between adjacent units Diagram showing the connection structure (1) between the steel embedded panel and the side walls Diagram showing the connection structure (2-1) between the steel embedded panel and the side walls Diagram showing the connection structure (2-2) between the steel embedded panel and the side walls Diagram showing the connection structure (3) between the steel embedded panel and the side walls

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 shows a construction example of a top slab that closes an opening on the ground side of a shaft as an embodiment of the present invention.

The vertical shaft 1 of this example is a rectangular vertical shaft for shield tunnel construction, and is constructed, for example, as follows.
For example, by the SMW (Soil Mixing Wall) construction method, a row-of-column type retaining wall 2 surrounding four sides is constructed from the ground G to the ground. erect steel piles.

When constructing the earth retaining wall 2, a diaphragm wall construction method may be employed. In this case, for example, a box-shaped steel member, which is an off-the-shelf steel continuous wall, is erected. Such a steel continuous wall can also be used as a steel pile.

After constructing the earth retaining wall 2, the inside of the rectangular opening enclosed by the earth retaining wall 2 on all sides is excavated, and a bottom slab 4 made of RC (reinforced concrete) is constructed on the floor surface. Similarly, by constructing side walls 5 made of RC on the inner surface, a vertical pit skeleton 7 in the shape of a bottomed square tube is constructed.

The vertical shaft 1 of this example is a starting vertical shaft for shield tunnel construction, and is used for carrying in a shield machine. During construction of the shield tunnel 8, the shaft 1 is used for carrying in various materials and equipment (segments, etc.) and for carrying out excavated soil. However, it is not limited to the starting vertical shaft, and may be an arrival vertical shaft or an intermediate vertical shaft.

In this example, after the completion of the shield tunnel 8, the top slab 9 is constructed at the ground side opening of the shaft 1 (shaft skeleton 7) so as to block the opening. This is to make it possible to use it as a park or the like by embanking the top slab 9 on the ground side of the vertical shaft 1 . In addition, the shaft space below the top slab 9 can be used as an emergency staircase or a common ditch (power lines, water supply and drainage pipes, ventilation openings). Incidentally, the ground-side opening of the shaft 1 is not necessarily entirely closed by the top slab 9, but is at least partially closed.

A method of constructing the top plate 9 will be described below.
First, a schematic description will be given with reference to FIGS. 2 and 3. FIG.

FIG. 2 shows the construction procedure of the top slab 9 using steel embedded panels that also serve as a formwork for constructing the top slab. Moreover, FIG. 3 is a side view of a steel-embedded panel. In this embodiment, the steel-embedded panel is composed of a first member 11, a second member 12 and a third member 13 (all of which are beam members).

FIG. 2(a) shows a preliminary process, which is carried out when the shaft 1 is constructed.
In the preliminary process, as shown in FIG. 2(a), of the walls (here, retaining walls 2A and 2B) facing each other across the ground side opening of the vertical shaft 1, the wall is installed in one wall 2A. The first member 11 protruding in the opposite direction is previously fixed to the upper end of the steel pile 3A (Fig. 3), and the upper end of the steel pile 3B (Fig. 3) installed in the other wall 2B The second member 12 protruding in the opposite direction is previously fixed to the portion.

Here, as shown in FIG. 3, the steel pile 3A and the first member 11 are fixed to each other through a splicing plate 31 or the like. Further, the steel pile 3B and the second member 12 are fixed to each other through the splicing plate 32 or the like. The steel frames may be fixed to each other by welding instead of using splice plates.

In the preliminary process, by installing the first member 11 and the second member 12 on the steel piles 3A and 3B, respectively, they protrude into the vertical shaft 1 from the wall side. It may fit within the plane of 2B, or it may protrude from the walls 2A and 2B toward the opening. In any case, by setting the overhang length from the steel piles 3A and 3B to about several 100 mm, there is no effect on carrying materials into the vertical shaft opening.

2(b) and 2(c) show the bridging process, which is carried out at the time of construction of the top slab 9 after the main materials and equipment such as the shield machine have been carried in and out through the opening on the ground side of the vertical shaft 1. As shown in FIG. Major materials and equipment include shield machines used in shield tunnel construction and segments that make up the lining of shield tunnels.
In the bridging step, as shown in FIGS. 2B and 2C, the third member 13 is installed between the first member 11 and the second member 12 to connect them.

In particular, in this embodiment, the third member 13 is divided into three, namely, left and right end members 13-1 and 13-2 in the bridging direction, and a center 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 in the girder direction (the length in the extending direction of the steel frame 22) of the shaft opening.

Therefore, first, as shown in FIG. 2(b), the third left end member 13-1 is connected to the first member 11 in a cantilever 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 steel frames of the first member 11 and the third left end member 13-1 are fixed to each other via a splicing plate 33 or the like, and the second member 12 and the third right end member 13 are fixed together. -2 fixes the steel frames to each other via the splicing plate 34 or the like. The steel frames may be fixed to each other directly by bolts and nuts without using the splicing plates 33, 34 or the like.

Next, as shown in FIG. 2(c), the third central member 13-3 is installed between the third left end member 13-1 and the third right end member 13-2 to connect them.

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

FIG. 2(d) shows the concrete placing process, which is carried out after the bridging process.
In the concrete placing step, as shown in FIG. 2(d), at least the third member 13 (13-1 to 13-3), particularly the first to third members 11 to 13 in this embodiment, are used as an embedded formwork. , pour concrete over them. In addition, necessary reinforcement may be arranged on the embedded formwork before placing. Thereby, the concrete layer 14 is formed on the first to third members 11 to 13, and the top slab 9 is constructed.

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

Fig. 4 is an enlarged view of the essential parts of the steel-embedded panel in Fig. 3, Fig. 5 is a cross-sectional view of one unit of the steel-embedded panel corresponding to the VV cross-section in Fig. 4, and Fig. 6 is between adjacent units of the steel-embedded panel. FIG. 10 is a cross-sectional view of a state connected with .

In this embodiment, the steel embedded panel is composed of first to third members 11-13.
In this embodiment, the first to third members 11 to 13 are respectively steel embedded panels, and the first to third members 11 to 13 (in order from the first member 11 side, the first member 11, the third member 13 , second member 12) are longitudinally connected to form one large steel-embedded panel.

Furthermore, the third member 13 in this embodiment is divided into three parts. 3. The third right end member 13-2 and the second member 12 are connected in the longitudinal direction to form one steel embedded panel.

Next, the structure of the steel embedded panel will be described with reference to FIGS. 4 and 5. FIG.
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 steel frame 22 is embedded in the precast concrete 21 in the lower section and exposed above the precast concrete 21 in the upper section.
As the steel frame 22, for example, H-shaped steel or I-shaped steel is used. 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 into one precast concrete 21, the member strength as a formwork can be further increased.

As shown in FIG. 5, the steel frames 22 in the steel-frame-embedded panel include a large number of small steel members (small beams) protruding in a direction perpendicular to the extending direction of the steel frames 22 for connecting the adjacent steel frames 22 . steel frame) 23 (23A, 23B). The small steel members 23 (23A, 23B) can be configured by small H-section steel or I-section steel welded and fixed to the web portion of the large H-section steel or I-section steel forming the steel frame 22 .

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

The panel unit (one unit of the steel-frame embedded panel) of FIG. It is composed of inner small steel members 23A connected to each other and outer small steel members 23B projecting outward from the two steel frames 22, respectively. Such a panel unit is manufactured before the bridging 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 units are connected by interposing the outer small steel members 23B with connecting members 25 having the same cross-sectional shape.
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, splicing plates 26 after disposing the connecting member 25 therebetween. It should be noted that joints may be used for connection instead of using the splicing plate 26 or the like. The connection here is made after the bridging process and before the concrete placing process.

In this embodiment, in order to facilitate the connection work on site, the ends of the outer small steel members 23B are slanted to form an upwardly open (wide) space between the outer small steel members 23B. A triangular (or inverted trapezoidal) connecting member 25 can be easily inserted from above. Note that the angle of the tip is not limited and may be vertical as is normally done.

Although the gaps between the units are exaggerated in FIG. 6, this is for the purpose of clarifying the units of the units. Also, each of the joints of the precast concrete 21 in the unit may be shaped like a key so that the cross section of the joint has a intermittent joint shape.

Next, a method of constructing the top slab 9 using the steel-frame embedded panel as described above will be described in more detail along the construction procedure of FIG. 2 and with reference to FIGS. 4 to 6. FIG.

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

The first member 11 (and the second member 12) are unitized by two steel frames in a direction perpendicular to the bridging direction. Although they are connected via the contact plate 26 or the like, they do not necessarily have to be unitized.

2(b) and 2(c), the third left end member 13-1 is lifted by a lifting machine such as a crane, carried on the extension of the first member 11, and The first member 11 and the third 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 connection work can be performed by using the precast concrete 21 of the first member 11 as a scaffolding, that is, by having the worker get on the precast concrete 21 on the wall side. Alternatively, a scaffolding projecting from the wall 2A may be installed for the work. The connection between the second member 12 and the third right end member 13-2 can be performed in the same manner.

In addition, the third left end member 13-1 and the third right end member 13-2 are unitized with two steel frames in a direction perpendicular to the bridging direction. 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 scaffolds.

Next, the third central member 13-3 is lifted by a lifting machine such as a crane, carried between the third left end member 13-1 and the third right end member 13-2, and 3 The central member 13-3 is connected and fixed via a splicing plate 35 or the like.
Such connection work can be performed by using the precast concrete 21 of the third left end member 13-1 as a scaffold, that is, by having the worker get 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 a splicing plate 36 or the like.
Such connection work can be performed by using the precast concrete 21 of the third right end member 13-2 as a scaffolding, that is, by having the worker get on the precast concrete 21 on the wall side.

In addition, the third central member 13-3, like the third left end member 13-1 and the third right end member 13-2, is unitized with two steel frames in the direction orthogonal to the bridging direction. Between the units, the outer small steel members 23B are connected to each other using connecting members 25 and splicing plates 26. FIG. 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 joints (divided parts) of the first to third members 11 to 13 (13-1 to 3) may be formed with slanted tips. This is for facilitating insertion and joining when a member (post-insertion member) to be joined to the member on the wall side is hung 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 V shape, insertion and joining easier to clean. At this time, the splicing plates 33 to 36 are preferably formed in a parallelogram according to the angles of the tip portions.

In the concrete placing process corresponding to FIG. 2(d), concrete is placed on the first to third members 11 to 13 as embedded forms. Thereby, the concrete layer 14 is formed on the first to third members 11 to 13, and the top slab 9 is constructed.

In the concrete placing process, reinforcing bars may be arranged on the form before concrete is placed. Such bar arrangement work can be performed using the precast concrete 21 of the first to third members 11 to 13 as scaffolding. By arranging reinforcing bars after the bridging process and before placing the concrete, the reinforcing bars and the steel frame-embedded panels are integrated with the concrete after the placing of the concrete, and a strong top slab is constructed.
In addition, by using a steel frame embedded panel as an embedded formwork, there is an advantage that the cross-sectional area of the reinforcing steel that should be originally arranged is covered by the cross-sectional area of the steel frame, and the amount of reinforcing bar arrangement (and the time and effort for reinforcing bar arrangement) can be simplified at the site.

Since the steel-embedded panel is divided in the longitudinal direction and unitized in the width direction, gaps (joints due to division or the like) are generated between divided bodies or units. Therefore, prior to placing the concrete, this gap is closed with a sealing material and/or a caulking treatment. In addition, the portion where the gap becomes large may be closed with a steel material plate.

In order to close the rectangular opening, it is necessary to connect not only the steel embedded panel and the wall in the girder direction but also the wall in the direction perpendicular to the girder direction. Connection between the wall (or pile body) perpendicular to the wall on the mounting side of the first and second members 11 and 12 (earth retaining walls 2A and 2B) and the top plate (the side along the steel frame extending direction) Regarding the connection between the wall (or pile body) and the first member 11, the second member 12 and the third member 13, the wall (pile body) is a concrete wall or RC pile (non-steel part ), follow the method (1) below, and if it is a steel wall or steel pile, follow the method (2) or (3) below. At this time, if stress transmission as a structure is expected even in the interface connection with the wall in the direction perpendicular to the girder direction, method (3) is desirable, and method (1) or (2) is selected. In this case, the purpose is only to integrate the wall body and the top slab as a member.

(1) As shown in FIG. 7, post-installed anchors 101 are driven into RC piles 3C that constitute walls (retaining walls) 2C in the direction perpendicular to the girder direction, or inserts embedded in advance in RC piles By this, it is integrated with the placed concrete in the concrete placing process.

(2) As shown in FIG. 8, a stud 102 is welded on site to a steel pile 3C that constitutes a wall (earth retaining wall) 2C in the direction perpendicular to the girder direction, or as shown in FIG. , the coupler 103A is previously welded to the steel pile 3C at the factory, and the reinforcing bar 103B is screwed on site. Then, these are integrated with the placed concrete in the concrete placing process.

(3) As shown in FIG. 10, a steel beam 104 is protruded in advance by welding or the like from a steel pile 3C that constitutes a wall body (earth retaining wall) 2C in a direction orthogonal to the girder direction, and the steel frame embedded panel side After arranging the connecting member 105 between the small steel members 23B, they are connected via, for example, a splicing plate 106 or the like. Then, these are integrated with the placed concrete in the concrete placing step.
In addition, as shown in FIGS. 7 to 10, in the gap between the wall body and the steel frame embedded panel in the direction crossing the girder direction, an interstitial mold made of a steel plate or the like is placed prior to placing the concrete. A frame 110 is placed.

In the wall in the direction perpendicular to the girder direction, even if there are partial concrete wall portions with exposed concrete and steel wall portions with exposed steel material, post-installed anchors and inserts in the concrete wall portion etc., and in the case of steel wall portions, studs, couplers, steel beams, etc. are preferably installed before the concrete placing process. At this time, the projecting post-installed anchors, inserts, studs, couplers, steel beams, etc. are connected to the small steel members 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 plan view and elevation view.

According to this embodiment, the first and second members 11 and 12 on the wall side and the third member 13 installed therebetween are the plate-like precast concrete 21 and the precast concrete 21 are arranged on the precast concrete 21 to a steel frame 22 extending in the longitudinal direction of the precast concrete 21, the lower section of which is embedded in the precast concrete 21, and the upper section of which is exposed above 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 mutual 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. After the connection, , 1st to 3rd members 11 to 13 can be used as a scaffold for work such as bar arrangement. Therefore, large-scale temporary construction such as total scaffolding and shoring from the shaft bottom can be eliminated. In addition, by using the steel-embedded panel, it is possible to reduce the on-site rebar arrangement amount (and rebar arrangement labor) as much as possible.

Further, according to the present embodiment, the first to third members 11 to 13 are used as embedded forms, and concrete is placed on them. , installation of formwork and dismantling and removal work are also unnecessary.

Further, according to this embodiment, the third member 13 is further divided into three in the longitudinal direction, and these divided bodies 13-1 to 13-3 are also connected to each other by their respective steel frames. By adopting such a divided form, it is possible to carry the product from the factory to the site and to store the size in a size that facilitates handling at the site. In other words, it is possible to avoid restrictions on public road transportation (length and width restrictions imposed by road traffic laws) and member weight restrictions (heavy member weights require heavy lifters with excessive specifications). In addition, by increasing the number of divisions of the third member 13, it is possible to cope with an increase in the span of the shaft opening. However, even when the number of divisions of the third member 13 is increased, 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 (eg, five).

Further, according to the present embodiment, when the third member 13 is divided into three pieces, the precast concrete 21 of the member on the wall side is used as a scaffold, and connection work is performed sequentially from the wall side (by so-called one-sided construction). Therefore, there is no need for large-scale temporary construction such as total scaffolding and shoring from the shaft bottom slab.

Further, according to this embodiment, the steel frame 22 in the steel frame embedded panel has the small steel members 23 protruding in the direction perpendicular to the extending direction thereof, and the adjacent steel frames 22 are joined together by the small steel members 23. .
As a result, the strength of the steel-frame-embedded panel in the direction (power distribution direction) orthogonal to the steel-frame extending direction can be improved. In addition, by having the cross-sectional area of the small steel member 23 take charge of the cross-sectional area of the reinforcing bars in the direction in which the bars should be arranged, the on-site bar arrangement amount (and labor for bar arrangement) can be further reduced in the direction of bar distribution, resulting in labor savings. can also contribute to

Further, according to the present embodiment, the steel-frame-embedded panel is divided into units in the direction orthogonal to the extending direction of the steel frames for each of the plurality of (two in this example) steel frames arranged in parallel. . By such unitization, the total number of members can be reduced, the efficiency of transporting the members from the factory to the site can be improved, and the labor required for lifting the members by a crane or the like can be reduced. In the unit, the steel frame 22 is connected via the inner small steel members 23A, thereby ensuring sufficient strength.

Further, according to this embodiment, the steel frame 22 in the steel-frame-embedded panel has the small steel members 23 protruding in the direction orthogonal to the extending direction thereof, and in the bridging process, the outer small steel members 23B of the adjacent panel units are separated from each other. 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) extends in the extending direction In the bridging process, the outer small steel members 23B of the adjacent steel-frame embedded panels are connected to each other. As a result, the panel units can be reliably connected and integrated.

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

In this case also, the first member 11 (or the second member 12) installed in advance on the wall side is used to perform the connection work between the first member 11 (or the second member 12) and the third member 13. Therefore, the efficiency of the top slab 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 foothold. This also eliminates large-scale temporary construction such as total scaffolding and shoring.

It should be noted that the illustrated embodiment is only a schematic illustration of the present invention, and that the present invention, in addition to what is directly indicated by the described embodiment, can also be made by those skilled in the art within the scope of the claims. Needless to say, it includes the improvement and change of

In the present invention, an embodiment of closing the opening on the ground side of a shaft (shaft skeleton) has been described, but a top slab that closes the upper end of an opposing wall in the ground can be widely used. .

1 Vertical shaft 2 (2A, 2B) Retaining wall 3 (3A, 3B) Steel pile 4 Bottom plate 5 Side wall 7 Vertical shaft skeleton 8 Shield tunnel 9 Top plate 11 First member 12 Second member 13 Third member 13-1 Third Left end member 13-2 Third right end member 13-3 Third central 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 member 26 Splicing plate 31 to 36 Splicing plate 101 Post-installed anchor 102 Stud 103A Coupler 103B Reinforcement bar 104 Steel beam 105 Connecting member 106 Splicing plate 110 Spacing formwork

Claims (5)

A method for constructing a top slab for closing an opening on the ground side of a vertical shaft, comprising:
When constructing the shaft, the first member projecting in the opposite direction is fixed in advance to the upper end of the steel pile installed in one of the walls facing each other across the ground-side opening of the shaft. a preliminary step of preliminarily fixing the second member projecting in the opposite direction to the upper end of the steel pile installed in the other wall;
A bridging step of installing a third member between the first member and the second member and connecting them when constructing the top plate;
A step of placing concrete on the third member as an embedded formwork;
including
The first member , the second member , and the third member are each arranged on a plate-shaped precast concrete and the precast concrete, extending in the longitudinal direction of the precast concrete, and having a cross-sectional lower portion a steel frame embedded in the precast concrete, the upper part of the cross section of which is exposed above the precast concrete;
A shaft top slab constructing method, wherein, in the bridging step, the first member and the third member, and the second member and the third member are connected by mutual steel frames. In the bridging step, the first member or the second member and the third member are connected by mutual steel frames using the precast concrete of the first member or the second member as a scaffold. The method for constructing the top slab of a vertical shaft according to claim 1 . 3. The method for constructing the top slab of a vertical shaft according to claim 1, wherein the steel-frame-embedded panel constituting said third member comprises a plurality of steel frames arranged in parallel on said precast concrete. The third member comprises a plurality of steel-frame-embedded panels divided in a direction orthogonal to the bridging direction in plan view ,
The steel frame in each of the plurality of steel-frame-embedded panels has a small steel member protruding from the steel frame in a direction orthogonal to the extending direction of the steel frame in a plan view ,
4. The method for constructing the top slab of a vertical shaft according to claim 3, wherein in said bridging step, small steel materials of adjacent steel-frame embedded panels are connected to each other. A top slab structure that closes the ground side opening of the vertical shaft,
a first member fixed to the upper end of a steel pile installed in one of the walls facing each other across the ground-side opening of the vertical shaft and projecting in the facing 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 disposed between and connected to the first member and the second member;
a concrete layer placed on the third member as an embedded formwork;
including
The first member , the second member , and the third member are respectively arranged on a plate-shaped precast concrete and on the precast concrete, extend in the longitudinal direction of the precast concrete, and extend in the lower section of the section. is embedded in the precast concrete, and a steel frame whose cross-sectional upper part is exposed above the precast concrete,
The top slab structure of a vertical shaft, wherein the first member and the third member, and the second member and the third member are connected by mutual steel frames.

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