JPS63277342A - Reverse execution of underground story - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a reverse construction method for a basement floor, and is a method for constructing a basement floor with a floor height larger than that of a normal basement floor. used for.

[Conventional technology]

When constructing a basement floor using the reverse construction method, by setting a via foundation at the position of the column and erecting a structural column (H steel, etc.) on top of it, and supporting the upper frame load on the structural column, Since the floor structure on the upper floor serves as a support for the retaining wall, it is common to not provide support such as struts.

However, even in the above-mentioned reverse construction method, the height of the basement floor is thicker (3.5m to 4.5m) than the normal floor height (3.5m to 4.5m).
If the excavation depth is deep until the construction of the next floor structure, increasing the strength (flexural rigidity, etc.) of the retaining wall would result in an enormous construction cost. Since this is uneconomical, a strut is sometimes installed near the middle of the floor to the next basement floor to support the retaining wall.

Conventionally, a steel strut such as an H-type steel has been used as the strut. These steel struts are installed in a lattice pattern at positions that avoid the alignment pillars, and are supported by temporary support piles at a suitable number of locations in the middle of the longitudinal direction (such as the intersections of the lattice pattern) to prevent buckling. It is configured as follows.

[Problem that the invention seeks to solve]

The above conventional example had the following problems:
In other words, because it is a reverse construction method, it is extremely difficult to carry in and out the long steel beams for the struts, and because the floor height is large,
It was difficult to bring in and repurpose formwork for the floor structure, reinforcing bars, and other materials, and due to the need to ensure safety, there were problems such as a decline in work efficiency and an increase in construction costs.

Many of these problems can be solved by making the struts an RC structure made of cast-in-place concrete. That is, when the struts are made of RC construction, the struts can be crushed after the construction of the basement floor structure and can be handled as concrete blocks, making it easy to carry them out of the site. Since the beam width of the RC strut can be set arbitrarily, there are advantages such as making the RC strut wider so that it can also be used as a work floor in the middle of the floor height.

However, when the RC struts are configured to be used also as a work floor, the following problems occur.

In other words, it is necessary to form an opening for excavation between the struts at a position that avoids the beams of the floor structure, but when using an RC construction work floor that also serves as a strut, the openings for excavation are required to be formed between the struts. Since the structure is wide, if it is erected in a lattice pattern in a position that avoids the center pillars, it will not be possible to create a large opening between the struts and the work floor, making it difficult to suspend the bulldozer. Excavation work below the work floor that also serves as a strut will be hindered, such as making it difficult to do so.

In addition, if the longitudinal middle part of the work floor that is also used as a sill beam was supported only with temporary support piles in the same way as to prevent buckling of a timber sill beam, the alignment columns and support piles would stand together, resulting in excavation. The work becomes extremely complicated and a decline in work efficiency is inevitable.

It is not impossible to eliminate the support piles by making the working floor that also serves as a stub beam as high in bending rigidity as the floor structure of the frame, but in this case, the working floor that also serves as a sill Despite being a temporary material that is intended to be crushed after use, it needs to be as thick or thicker than the permanent floor structure, and requires a large amount of concrete and reinforcing steel. (The chiseling work during disassembly and removal becomes troublesome, and the amount of chiseled debris to be carried out becomes enormous.)

An object of the present invention is to solve these problems.

[Means for solving problems]

The technical means taken by the present invention to achieve the above object are as follows. That is, in the basement floor reverse construction method according to the present invention, after constructing a retaining wall and a center column, excavating the ground inside the retaining wall to a predetermined depth and constructing the floor structure of the upper floor, The ground is excavated to a predetermined depth, and at the bottom of the excavation, concrete is poured in a substantially grid pattern at positions including the core pillars, and an RC construction work floor that also serves as a sill is supported by the core pillars. The structure is characterized in that the floor structure of the upper floor is constructed by excavating the ground below the strut and working floor to a predetermined depth.

[Effect]

According to the above configuration, since the RC construction work floor that also serves as a sill and beam is constructed by pouring concrete on the excavation floor in a substantially grid pattern, the bottom formwork of the work floor that also serves as a sill and the bottom formwork can be No shoring is required.

Since the RC construction work floor is supported by the structural pillars, it is possible to omit or reduce the number of temporary support piles, and even if the width of the work floor is wide, it is possible to perform the work as a stub. A large opening can be formed between the floors.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic cross-sectional view of the whole. In the same figure, 1
is a retaining wall made of columns or continuous walls, etc., 2 is a central column, and 3 is an R
It is a work floor of C construction that also serves as a cut beam, and is constructed in a substantially lattice-like manner at the positions connecting the structural pillars 2, with both ends expanding into a fan shape. 4 is an RC-made stand-up. 5 is an opening for excavation.

FIG. 2 is a longitudinal sectional view of the main part, and FIG. 3 is an enlarged view of the main part. In the figure, 6 is a floor structure on the first floor above ground, and 7 is a floor structure on the first floor underground, which has a low floor height.

8 is a floor structure on the second basement floor with a large floor height, and 9 is a floor structure on the third basement floor with a large floor height. The floor structure 6.7 up to the first basement floor is the same as the conventional construction method, but the second basement floor has a large floor height.
, the third floor floor structure is constructed by installing the working floor 3 which also serves as a strut. 10 is an underground beam, and 11 is a pier foundation.

a indicates the excavated bottom of the primary excavation, b indicates the excavated bottom of the secondary excavation, C indicates the excavated bottom of the tertiary excavation, d indicates the excavated bottom of the fourth excavation, and e indicates the final excavated bottom of the fifth excavation. 12...
is a suspended formwork for the floor structure, and for the floor structure on the upper floor,
Hanging hardware consisting of a hanging rod 13 such as a threaded reinforcing bar or a steel rod with threaded portions formed at both ends, a nut member 14 such as a hexagonal nut or a hexagonal long nut (a coupler for threaded reinforcing bars), etc. It is suspended and supported through.

The work floor 3 that also serves as a stub beam is suspended and supported by the floor structure of the upper floor via the hanging rods 13 . . . , nut members 14 . ing. That is, as shown in FIGS. 4 and 5, anchorage reinforcing bars 16 are welded to the four sides of each centering column 2 at predetermined positions, so that the load of the working floor 3 that also serves as a sill is transferred to the centering column 2. 2.

Reference numeral 17 in FIG. 5 is a hanging muscle of the abdominal stand-up 4.

Next, we will explain the reverse construction method for the basement floor step by step.

As shown in Figure 6 (a), after constructing the retaining wall 1,
The structural pillars 2 are erected, the pillars 18 are cast, and the gantry 19 is assembled.

As shown in FIG. 6(b), an excavator (not shown) mounted on the gantry 19 performs primary excavation up to point a.

As shown in Fig. 6 (c), a column steel frame 20
At the same time, the corporate formwork 21 and the floor structure formwork 2 are joined.
2 are assembled, reinforcement is placed, and concrete is poured to construct the floor structure 6 and part of the columns 23 on the first floor above ground.

As shown in Figure 6 (d), the gantry 19 is removed and the
Using the floor structure 6 of the floor as a working floor, secondary excavation is performed from an opening provided in a part of the floor structure 6 (a position that matches the opening 5) to a predetermined depth.

As shown in Fig. 6 (E) and Fig. 2, the hanging formwork 12 is suspended from the floor structure 6 on the first floor above ground, and reinforcement and concrete are placed inside it to construct the floor structure on the first basement floor. Build body 7.

As shown in FIG.
Next, excavation is carried out, and on the excavation bottom C, side formwork 24 is placed in a substantially lattice shape including the above-mentioned core pillars 2, reinforcing steel bars are arranged, and dirt floor concrete is poured. Build a work floor 3 that can also be used as a cross beam. Here, earthen floor concrete refers to excavated bottom C.
This refers to concrete that is poured directly without laying a bottom form, but it also includes cases where concrete is poured by laying a waterproof sheet such as vinyl. In addition, the hanging hardware consisting of the hanging rods 13..., nut members 14..., etc. will be removed from the floor structure 6 on the first floor above ground after the concrete of the floor structure 7 on the first basement floor has achieved the required strength. , as shown in the figure, from the floor structure 7 on the first basement floor to the side formwork 24...
・Although not shown, the washer 15 is also attached to the lower end of the hanging rod 13 with a NAND member 14.

As shown in Figure 6 (G), the working floor 3 that also serves as the first stage strut
After the concrete has developed the required strength, a fourth excavation is performed to a predetermined depth d.At the excavation bottom d, as shown in the figure, a second stage of cutting is performed prior to the floor structure 8 on the second basement floor. Concrete pouring of the beam-cum-working floor 3 is performed, but this may be done after the floor structure 8 on the second basement floor is constructed. As shown in the figure, a hanging formwork 12 for the floor structure on the second basement floor is attached to the floor structure 7 on the first basement floor, and a hanging rod 13 that passes through the first stage strut-cum-working floor 3 and the hanging formwork 12 are attached to the floor structure 7 on the first basement floor. With the suspension suspended via the added hanging rods 13'' and all or most of the load supported by the floor structure 7 on the first basement floor, reinforcing and concrete placement were carried out as shown in Fig. ), a floor structure 8 on the second basement floor is constructed.

As shown in Figure 6 (S), the second stage working floor 3
After the required strength is achieved in the concrete, a fifth excavation is performed to a predetermined depth e, and the underground beam IO and the floor structure 9 on the third basement floor are constructed.

After that, after the underground beams 10 and the concrete of the floor structure 9 on the third basement floor have achieved the required strength, the second stage strut-cum-working floor 3 is removed.6 Then the first-stage strut-cum-working floor is removed. 3 will be removed, but this can also be removed at an appropriate time in advance.

In the above embodiment, the working floor 3 that also serves as a stub beam at each level is supported by the center pillars 2, and the hanging rods 1 are attached to the floor structure of the upper floor.
3. Since it is suspended via the nut member 14, washer 15, etc., no temporary support piles are used to prevent buckling, but temporary support piles may be used. Even in this case, since the lattice-like intersections of the working floor 3 which also serves as a sill beam are supported by the centering columns 2, the number of temporary support piles used can be reduced.

Furthermore, depending on the spacing between the core pillars 2 and the cross-sectional shape of the working floor 3 that also serves as a strut, it is possible to omit the temporary support piles and hanging rods.

The RC surfacing 4 can also be constructed by pouring concrete on the excavation bottom which forms the shape of the road surface and the lower surface of the working floor 3 which also serves as a strut, but in this embodiment, as shown in FIG. In this case, only the vicinity of the retaining wall 1 is about 80 to 100 cm deeper than the lower surface position of the working floor 3 that also serves as a sill, and about 80 to 100 cm
Excavate to a width of about 00c11, and extend the upper opening of the trench-like excavation part 25 to the bracket 26, such as an angle material, attached to the retaining wall l, and the excavation bottom of the three examples of working floors that can also be used as struts! !
It is closed with a bottom formwork 27 made of a henier or the like placed thereon, and reinforcement and concrete placement are performed on the bottom formwork 27 to construct the raised-up part 4. In this way, when the trench-like excavation section 25 is excavated, it is possible to check whether there is a water stoppage defect in the retaining wall 1 up to the bottom level of the trench-like excavation section 25 and, if necessary, to stop the water. After completing the construction and confirming that the water has stopped flowing, the trundle 4 and the working floor 3 that can also be used as a strut will be constructed.

Therefore, even if the upper part of the ground is covered over a wide area by the strut-beam work floor 3 and the raised berth 4, the ground below the strut-beam work floor 3 is covered with a bulldozer.
When digging to the side, the bulldozer should be advanced to a position as close as possible to the soil retaining wall l even if water comes out due to failure of the retaining wall 1 below the bottom of the groove-shaped excavation part 25 to stop water. This allows water stoppage work to be carried out easily.

7 and 8 show another embodiment of the present invention. In this embodiment, the working floor 3 which also serves as a struver at each level is suspended and supported by the floor structure 7°8 of the upper floor using a hanging rod 13, a nut member 14, a washer 15, etc. A temporary support 28 such as a pipe support is installed between the floor structure 7.8 of the upper floor.
... is used to prevent the central part of the working floor 3 that also serves as a strut from being deformed upward due to the earth pressure acting on the retaining wall l. The other configurations are the same as those in the previous embodiment, so explanations will be omitted.

〔Effect of the invention〕

Since the present invention has the above-described configuration, it can achieve the following effects.

■The RC construction work floor serves as a sill to support the retaining wall, and is also used as a work passageway and a storage area for materials such as formwork and reinforcing bars for the floor structure, so it is used as a storage area for materials such as formwork and reinforcing bars for the floor structure. Even if the height is large, it can be constructed easily and safely.

■Since the concrete floor is poured at the bottom of the excavation to construct the RC work floor that also serves as a sill and beam, there is no need for a bottom formwork for the work floor that also serves as a sill and support for the bottom form.

■Since we will construct an RC work floor that also serves as a sill and beam by pouring concrete on the excavation floor in a roughly grid pattern at locations including the core pillars, even if the width of the work floor that also serves as a sill and beam is wide, The area of the opening between the beam and work floor can be increased,
In addition, since the work floor that also serves as a sill and beam is provided in a state where it is supported by the center pillars, it is possible to omit or reduce the number of temporary support piles without increasing the thickness of the work floor that also serves as a sill. As a result, ground excavation work can be carried out easily and efficiently.

■Since the RC construction work floor is supported by the structural columns, a relatively thin work floor is sufficient for the work floor, which requires less concrete and reinforcing bars, and is easy to chisel during demolition and removal. It is easy to work and transport the hanging glass.

[Brief explanation of drawings]

Figures 1 to 6 (A) to (S) show one embodiment of the present invention, in which Figure 1 is a schematic cross-sectional view of the whole, Figure 2 is a longitudinal sectional view, and Figure 3 is a main part. Enlarged view, Figure 4 is a plan view of the main part, Figure 5
The figure is a longitudinal sectional view of the main part, and FIGS. 6(A) to 6(S) are process explanatory views. 7 and 8 show another embodiment of the present invention, with FIG. 7 being a schematic longitudinal sectional view and FIG. 8 being a longitudinal sectional view of the main part. 1... Mountain retaining wall, 2... Center column, 3... Work floor that also serves as a strut, 6, 7, 8.9... Floor structure.

Claims (1)

[Claims] After constructing the retaining wall and pillars, excavating the ground inside the retaining wall to a specified depth and constructing the upper floor floor structure,
The ground is excavated to a predetermined depth, and at the bottom of the excavation, concrete is poured in a substantially grid pattern at positions including the core pillars, and an RC construction work floor that also serves as a sill is supported by the core pillars. A reverse construction method for a basement floor, which is characterized by constructing a lower floor floor structure by excavating the ground below the strut and working floor to a predetermined depth.