JPH07103583B2 - Construction method for large span underground structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction method for a large span underground structure.

[0002]

2. Description of the Related Art Conventionally, in order to construct an underground structure, after a temporary steel frame column is built, a temporary timber girder and a ventilating material are also erected and excavated. Then, with the progress of root cutting, the number of cutting beams is gradually increased to two steps and three steps. When the underground structure has a large span and a large number of layers deep in the ground, naturally the number of steps of this girder also increases and the amount of temporary material also increases.

By the way, it is possible to remarkably improve the economical efficiency if the main pillars / beams can also be used as the temporary fittings for the mountain retaining instead of the temporary steel pillars, the beams and the uprising members. As one of such permanent beam construction methods, first, a true structural column (steel tube column) is built during pile construction, and then a steel box beam, which corresponds to a conventional beam, is attached. After that, concrete is poured into the inside to construct a supporting structure for the retaining wall, and the next excavation work is started. Furthermore, a steel box beam on the floor directly below will be installed, and internal concrete pouring and excavation will be repeated to proceed with the underground structure work.

In addition, a cross H-shaped column made by assembling a H-shaped steel in a cross shape is used as a structure column, and an H-shaped steel frame beam is erected, and concrete around the H-shaped beam and the floor slab is installed. There is also a method of constructing a supporting structure for the mountain retaining wall by casting.

[0005]

Even in the permanent beam construction method, it is necessary to provide a support frame for the mountain retaining wall including the structure columns in the reverse construction, and the length of the structure columns and the beams to be attached to them are the structure columns. There are many troubles such as being affected by the installation dimension accuracy. The object of the present invention is to eliminate the disadvantages of the above-mentioned conventional example, to eliminate the need for mountain beams, support works, structural columns, etc., to make construction simple and safe, and to shorten the construction period and reduce costs. It is said to provide a construction method for structures.

[0006]

In order to achieve the above object, the present invention performs a primary root cutting in the interior surrounded by a continuous underground wall, and directs a slit-like beam loading opening in the center in the short span direction. A work floor with an opening for loading and unloading earth and sand at the end, and a secondary root cutting is performed below the working floor, and the beam loading opening is formed from the part where the secondary root cutting is completed. The beam is carried in from above, the beam is moved laterally, laid side by side in the direction of the short span of the underground continuous wall and integrated with the concrete slab that forms at the upper end, and a slit-shaped beam loading opening is made short in the center. Formed in the span direction, and also formed an underground slab with an opening for loading and unloading sediment at the end, followed by the same root cutting, carrying in a beam from the opening, and forming an underground slab with the beam carried in. Repeat each step of, after several root cutting,
The main point is to construct a mat slab.

[0007]

According to the present invention, the beams are laid out in the short span direction of the underground continuous wall and integrated with the slab concrete, and it is possible to construct a pillarless space using the slab as a mountain-cutting girder. Necessary mountain girders, supports, construction columns, etc. are unnecessary. Also, an underground work space that is not affected by the weather can be secured. In this way, the work of formwork is eliminated, and the work period and cost can be reduced.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a first step of the construction method for a large-span underground structure of the present invention, and FIG. 2 is a plan view of the same.
In the figure, reference numeral 1 is an underground continuous wall, and the space surrounded by the underground continuous wall 1 is dug down to the height of a beam by using the primary root cutting as a primary root cutting, and a working floor 2 is formed there. A slit-shaped beam loading opening 3a is provided at the center of the work floor 2 in the short span direction, and earth and sand loading openings 4a are provided at both ends. Figure 5
Is a beam loading crane installed on the opening 3a, and 6 is an earth removing device installed on the opening 4a. Further, the work floor 2 is used as a PC member stock yard 18, where the PC beam 7 is assembled and prestress is introduced.

The work floor 2 may be made of reinforced concrete which is constructed on site by placing reinforcing bars and concrete, but as shown in FIGS. 9 and 10, the PC steel wire extends in the short span direction of the underground continuous wall 1. Laying out the PC beams 7 with 8 arranged,
A concrete slab 9 is formed on the upper end of the C beam 7,
The C beam 7 and the concrete slab 9 are integrally configured.
FIG. 9 shows a concrete slab 9 constructed by placing concrete in the gap using the PC beam 7 as a formwork, and 10 in the figure is a slab rebar. Figure
10 is a composite beam in which a formwork 11 is placed on the upper end of the PC beam 7 and a concrete slab 9 is constructed using this formwork 11. A steel frame beam may be used instead of the PC beam 7.

As a second step, as shown in FIG. 3, a secondary root is cut below the work floor 2. In this secondary root cutting,
In addition to the earth and sand carrying-out opening 4a, the beam carrying-in opening 3a can also be used for carrying out earth and sand.

As a third step, as shown in FIG. 4, the PC beam 7 or the steel frame beam is carried in from the slit-shaped opening 3a of the work floor 2 from the portion where the secondary root cutting is completed, and the carried-in beam is removed. An underground slab 12 is constructed by laterally moving and laying them out in the short span direction of the underground continuous wall 1 and forming a concrete slab 9 on the upper end thereof. In this case, the end of the PC beam 7 or steel beam is joined to the underground continuous wall 1 as shown in FIG.
For that purpose, the PC beam 7 is supported by the PC beam receiving concrete 14 of the root cutting bottom 13, and the mold 11 is arranged on the upper end of the PC beam 7 as shown in FIG. When the concrete slab 9 is constructed using the composite slab 9 to form a composite beam, it is connected to the continuous wall 1 by the shear reinforcing bar 15. Alternatively, as shown in FIG. 9, the PC beam 7 may be used as a formwork and concrete may be placed in the gap so that the concrete slab 9 is formed on the concrete.

As shown in FIG. 5, the underground slab 12 has a slit-shaped beam carrying-in opening 3b in the center thereof corresponding to the beam carrying-in opening 3a and the earth and sand carrying-out opening 4a of the work floor 2.
In addition, an opening 4b for carrying out earth and sand is provided at the end. Then, as a fourth step, a third root is cut below the underground slab 12, and the PC beam 7 or the steel beam is carried in from the slit-shaped opening 3a of the working floor 2 from the portion where the root cutting is completed,
The beams that have been carried in are laterally moved and laid side by side to form a concrete slab 9 on the upper end of the beams, and an underground slab 12 is provided on the basement floor.
Build an underground slab 12 for two basements below.

Below, the root cutting below the underground slab 12, P
Underground slab with C-beam 7 or steel beam loaded and loaded
Repeat each step of forming twelve. As shown in FIG. 6, floor cutting is performed after root cutting after several orders, for example, the mat slab 16a in the central portion is first constructed, and the island continuous beam 17 supports the underground continuous wall 1 as a retaining wall. . Then, as shown in FIGS. 7 and 8, a mat slab 16b around the central mat slab 16a is installed to complete the construction.

As described above, the present invention is an underground slab 12 in which PC beams 7 or steel beams are laid side by side and a concrete slab 9 is formed at the upper end of the underground slab 12, and a pillar-free space is constructed by using the underground slab as a mountain-fixing beam. Furthermore, it is a reverse construction method in which the basement floor is constructed by excavating under the underground slab 12. The flow of soil pressure is shown by arrows in FIG. 2, and the soil pressure α received on the long span side of the continuous wall 1 is balanced with the facing soil pressure α. The earth pressure γ received on the short span side is transmitted to the side earth pressure wall by the shear force β.

[0015]

The construction method of a large span underground structure of the present invention described above can secure an underground work space that is not affected by weather, and does not require mountain beams, support beams, or true columns.
Since these do not become obstacles, the workability and safety are improved, and the construction period and cost can be reduced. Furthermore, since no formwork is required, it will be possible to deal with the shortage of craftsmen, which will lead to a shorter construction period and lower costs.

[Brief description of drawings]

FIG. 1 is the first construction method of a large span underground structure of the present invention.
It is a perspective view showing a process.

FIG. 2 is the first construction method of the large span underground structure of the present invention.
It is a top view which shows a process.

FIG. 3 is a vertical sectional front view showing a second step.

FIG. 4 is a vertical sectional front view showing a third step.

FIG. 5 is a vertical cross-sectional front view showing a fourth step.

FIG. 6 is a vertical sectional front view showing a step before the final step.

FIG. 7 is a vertical sectional front view showing a final step.

8 is a cross-sectional view taken along the line AA of FIG.

FIG. 9 is a cross-sectional view showing an example of a work floor and an underground slab.

FIG. 10 is a cross-sectional view showing another example of the work floor and the underground slab.

FIG. 11 is a vertical cross-sectional front view showing joining of an underground continuous wall and an underground slab.

[Explanation of symbols]

1 ... Basement continuous wall 2 ... Work floor 3a, 3b ... Beam loading opening 4a, 4b ... Sediment loading opening 5 ... Crane 6 ... Excavator 7 ... PC beam 8 ... PC steel wire 9 ... Concrete slab 10 ... Slab Reinforcing bar 11… Sterling formwork 12… Underground slab 13… Root cutting bottom 14… PC beam receiving concrete 15… Shearing rebar 16a, 16b… Mat slab 17… Cut beam 18… PC member stockyard 19… Wall or pillar

Claims (1)

[Claims] 1. A primary root cutting is performed in an interior surrounded by an underground continuous wall, and a beam-carrying opening having a slit shape is formed in the center in the short span direction, and a sand-carrying-out opening is provided at an end. The work floor provided is formed, the lower part of this work floor is subjected to secondary root cutting, the beam is loaded from the beam loading opening from the part where the secondary root cutting is completed, and the loaded beam is laterally moved. Aiming at integration with the concrete slab that is laid out in the short span direction of the underground continuous wall and formed at the upper end thereof, a slit-shaped beam loading opening is formed in the center in the short span direction, and
Forming an underground slab with an opening for loading and unloading sediment, repeat the same steps of root cutting, carrying in a beam from the opening, and forming an underground slab with the carried-in beam. After that, a construction method for a large-span underground structure is characterized by constructing a mat slab.