JP2012107430A - Construction method of underground structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method of an underground structure capable of shortening a construction period while reducing influence on surroundings and reducing or omitting lighting equipment and ventilation equipment further.SOLUTION: The construction method of an underground structure is for constructing a new underground structure while demolishing an existing underground structure. By alternately performing a demolition process of constructing earth retaining 100 around the existing underground structure and then demolishing a part positioned on the top story in the remaining existing underground structure and a ring construction process of constructing outer peripheral rings 3,4,5,6 with openings 30,40,50,60 formed at the center part, which are the outer peripheral part of the new underground structure, inside a space formed by the demolition process, the outer peripheral part of the new underground structure is successively constructed from the top story while successively demolishing the existing underground structure from the top story, and after the demolition of the existing underground structure is ended, the center part of the new underground structure is constructed on the inner side of the openings 30,40,50,60 of the outer peripheral rings 3,4,5,6.

Description

  The present invention relates to a method for constructing an underground structure that involves the dismantling of an existing underground structure.

In recent years, an existing building with a large underground structure with a large floor area and a large depth has been demolished, and a new building with a large underground structure with a large depth and a large floor area has been newly constructed at that location. is there. In such construction work, in order to prevent the influence on the surrounding infrastructure and buildings, it is necessary to construct a mountain retaining around the existing underground structure and to suppress the deformation (falling) of the mountain retaining due to earth pressure. is there.
Conventionally, for example, the following two methods are conceivable as the construction method of the construction work described above.

(1) Full beam method This method involves first dismantling the superstructure of the existing building, then building a retaining ring around the underground structure of the existing building, and then dismantling the existing underground structure sequentially from the upper floor. Then, lay the beam in the horizontal direction on the entire inner surface of the mountain. This cutting beam can suppress the deformation of the mountain retaining due to the dismantling of the existing underground structure. Then, after the dismantling of the existing underground structure is completed, root cutting and flooring are performed to form a pressure-resistant panel. Next, after building the steel part of the underground part from the pressure platen, the first floor slab was placed in advance, and then the underground part was constructed sequentially from the lowest floor (forward construction method), and in parallel with that, the ground Proceed with groundwork by building part of the steel frame. Thereby, since the underground work and the ground work can proceed simultaneously, the construction period can be shortened.

(2) Full-face reverse hammering method This method involves dismantling the superstructure of the existing building, building a retaining ring around the underground structure of the existing building, and then dismantling the existing underground structure sequentially from the upper floor. Slabs of new underground structures are sequentially built from the upper floors in the space formed by the dismantling (see, for example, Patent Document 1 below). That is, first, the first-floor part of the existing underground structure (the first-floor beam slab and the first-floor pillar wall) is disassembled, and then the first-floor slab of the new structure is built over the entire surface. Subsequently, the second basement part of the existing underground structure (the first basement beam slab and the second basement column wall) is demolished, and then the first basement slab of the new structure is built over the entire surface. By repeating the dismantling of the existing underground structure and the construction of the new structure in this manner, the new underground structure is sequentially built from the upper floor while the existing underground structure is sequentially demolished from the upper floor. According to this construction method, the slabs of new structures that are built sequentially become support structures that support the mountain retaining, and because it is more reliable than the above-mentioned beams, it is a large-scale underground work with a large depth and large area. However, it is possible to reliably suppress the deformation of the mountain retaining and reduce the influence on the surrounding infrastructure and the like. In addition, after the construction of the first floor slab of a new structure, the ground work will be carried out by building a steel frame on the ground part in parallel with the underground work. Thereby, since the underground work and the ground work can proceed simultaneously, the construction period can be shortened.

JP 2002-61213 A

  However, when the above-mentioned full beam method is performed in a large-scale construction, it is difficult to sufficiently suppress the deformation of the retaining ring. In addition, since the full-cut beam method requires a considerable number of cut beams, it takes a considerable amount of time to install and dismantle the cut beams, and there is a problem that the construction period of the underground work becomes long. In addition, the existing underground structure is built with a beam inside the retaining ring at the time of dismantling, and it is difficult to use large heavy machinery, so dismantling work will be done with small heavy machinery, and the construction period of dismantling work will be long There's a problem. In particular, when the existing underground structure is relatively new, there is a case where the frame has high strength and is difficult to disassemble with a small heavy machine.

  In addition, since the slab of the new structure to be built in advance is formed over the entire surface in the above-described whole surface reverse driving method, a large heavy machine can be used as a work space for the dismantling work performed under the slab. It is not high enough. Therefore, since the existing underground structure is dismantled with a small heavy machine, there is a problem that the construction period of the dismantling work becomes long. In addition, the construction of the first floor slab of a new structure blocks the underground part, and the work site of the underground work becomes dark even during the daytime, so a large number of lighting facilities are required. In addition, even after the underground portion is blocked as described above, since the dismantling work by the heavy machinery is performed, the exhaust gas of the heavy machinery is likely to accumulate in the underground construction work place. For this reason, it is necessary to install a large number of ventilation equipment for ventilating the work site of the underground construction, and if the number of operating heavy machines is limited in order to reduce the amount of exhaust gas generated, the construction period becomes longer.

  The present invention takes the above-described conventional problems into consideration, and can reduce the work period while reducing the influence on the surroundings, and further can reduce or omit lighting equipment and ventilation equipment. It aims at providing the construction method of a structure.

  The construction method of an underground structure according to the present invention is a construction method of an underground structure that constructs a new underground structure while dismantling the existing underground structure, and after building a mountain retaining around the existing underground structure A dismantling process for dismantling a portion located on the uppermost floor of the remaining existing underground structure, and a space formed by the dismantling process in an outer peripheral part and a central part of the new underground structure By alternately performing a ring construction process for constructing an outer ring with openings formed therein, the existing underground structure is sequentially disassembled from the upper floor, and the outer periphery of the new underground structure is sequentially constructed from the upper floor. After the dismantling of the existing underground structure, the central part of the new underground structure is built inside the opening of the outer ring.

  With such a feature, the outer ring, which is the outer peripheral part of the new underground structure, is built in advance, so that the outer ring suppresses the deformation of the retaining ring, and the beam is omitted or reduced. Moreover, since the central part of the newly constructed structure is formed in a blow-by shape by the opening of the outer peripheral ring built in advance, it is used for the dismantling work of the existing underground structure from the opening of the outer peripheral ring. Heavy machinery, equipment, and materials for new underground structures will be carried in. In addition, the opening of the outer ring ensures a sufficient height (large space) at the center of the underground construction work site to allow large heavy machinery to be used. In addition, sunlight is radiated from the opening of the outer ring to the underground work place, and the underground work place is ventilated from the opening of the outer ring.

The underground structure construction method according to the present invention includes, before the ring construction step, a built-in column that penetrates the existing underground structure and is supported by the ground below the existing underground structure. The outer peripheral ring is preferably supported by the true pillar.
Thereby, since an outer periphery ring is supported by a structure pillar, the support work which supports an outer periphery ring temporarily is abbreviate | omitted or reduced.

In the underground structure construction method according to the present invention, it is preferable that the opening of the outer ring is formed in a polygonal shape or a circular shape in which a haunch is formed at a rectangular corner in a plan view. .
As a result, when an external force acts on the outer peripheral ring from the mountain clamp, the stress is less likely to be concentrated in one place and is easily dispersed, so that the opening of the outer peripheral ring can be formed larger.

  According to the construction method of the underground structure according to the present invention, the outer ring that suppresses deformation of the mountain retaining ring is more reliable than the cut beam, so even if it is a large-scale underground construction with a large depth and large area, Deformation can be reliably suppressed. Further, since the cutting beams can be omitted or reduced, the process of installing and disassembling the cutting beams can be shortened or omitted, and the construction period can be shortened.

In addition, the outer ring that is built in advance has an opening in the center, and a sufficient height (large space) is secured in the central part of the underground work place to allow large heavy machinery to be used. Large heavy machinery can be introduced. Thereby, the work period of the dismantling work can be shortened. Even when the existing underground structure is relatively new and high in strength, it can be easily dismantled by using a large heavy machine.
Moreover, since sunlight is irradiated to the underground construction workplace from the opening of the outer ring, the underground construction workplace is very bright. Therefore, the lighting equipment can be reduced or omitted.
Further, since the work of the underground work is ventilated by the opening of the outer ring, the exhaust gas of heavy equipment is difficult to accumulate in the work of the underground work. Therefore, ventilation equipment can be reduced or omitted. In addition, since the work place of the underground construction can be sufficiently ventilated, a large number of large heavy machinery having a large displacement can be operated at the same time, and the work period of the dismantling work can be shortened.

It is a perspective view of a new underground structure under construction for explaining an embodiment of the present invention. It is sectional drawing showing the construction condition (a primary dismantling process, a mountain retaining process, a construction pillar construction process) of the underground construction for demonstrating embodiment of this invention. It is sectional drawing showing the construction condition (primary ring construction process) of the underground construction for demonstrating embodiment of this invention. It is sectional drawing showing the construction condition (secondary dismantling process) of the underground construction for demonstrating embodiment of this invention. It is sectional drawing showing the construction condition (secondary ring construction process) of the underground construction for demonstrating embodiment of this invention. It is sectional drawing showing the construction condition (tertiary dismantling process) of the underground construction for demonstrating embodiment of this invention. It is sectional drawing showing the construction condition (tertiary ring construction process) of the underground construction for demonstrating embodiment of this invention. It is sectional drawing showing the construction condition (quaternary dismantling process) of the underground construction for demonstrating embodiment of this invention. It is sectional drawing showing the construction condition (quaternary ring construction process) of the underground construction for demonstrating embodiment of this invention. It is sectional drawing showing the construction condition (final root cutting process) of the underground construction for demonstrating embodiment of this invention. It is sectional drawing showing the construction condition (foundation floor construction process) of the underground construction for demonstrating embodiment of this invention. It is sectional drawing showing the construction condition (underground center part construction process) of the underground construction for demonstrating embodiment of this invention.

  Hereinafter, an embodiment of a construction method for an underground structure according to the present invention will be described with reference to the drawings.

  The dismantling / construction work described below involves dismantling an existing building with a large underground structure with a large floor area and a new building with the same large underground structure at that location. In the present embodiment, the construction method of the underground structure will be mainly described.

  The construction method of the underground structure in the present embodiment is that the existing underground structure 10 is sequentially dismantled from the upper floor while the outer periphery of the new underground structure 1 is sequentially built from the upper floor (reverse placement method) to FIG. As shown, after constructing a new underground structure 1 ′ having a large opening 30, 40, 50, 60 formed in the central portion in plan view, the central portion of the new underground structure 1 is formed in the opening 30, 40, 50, 60. This is a method of constructing a new underground structure 1 by sequentially building the building from the lower floor (sequential construction method).

  In detail, first, an upper structure (not shown) of an existing building is dismantled, and then the uppermost part of the existing underground structure 10 is dismantled and is piled around the existing underground structure 10 as shown in FIG. 100 is built, and a construction pillar 2 for supporting the slab of the new underground structure 1 is built.

  Specifically, first, a dismantling process (primary dismantling process) for disassembling the underground first floor portion 11 located on the uppermost floor among the remaining existing underground structures 10 is performed. That is, the first-story beam slab 11a and the underground first-story columnar wall 11b of the existing underground structure 10 are each dismantled by a known dismantling method. Then, after the dismantling is completed, a casing rotating excavation for installing a not-illustrated mountain retaining machine and the structural pillar 2 in the space formed by the dismantling after the dismantling process and the structural pillar construction process described later. A gantry (not shown) is installed to install the machine.

  Next, a mountain retaining process for constructing the mountain retaining 100 is performed. This mountain-clamping process can be performed by a publicly-known mountain-clamping work. Examples of the mountain-clamping 100 include an SMW (Soil Mixing Wall) wall.

  Next, a construction pillar construction process for constructing the construction pillar 2 described above is performed. The structural pillar 2 is a pillar member made of steel such as a steel pipe or a section steel, and is fixed and supported in the ground G below the existing underground structure 10, and is a pressure plate of the new underground structure 1 described later. Stands from the top. The construction pillar 2 penetrates through the existing underground structure 10 and protrudes to the upper position of the first floor of the new underground structure 1. As a method of building such a structural pillar 2, first, a casing (not shown) is rotated by a casing rotary excavator (not shown) to penetrate the existing underground structure 10, and the ground below the existing underground structure 10 is placed. Drill holes to a predetermined depth of G. Next, the temporary pile 20 is formed by inserting the lower end of the structural pillar 2 into the hole formed in the ground G and placing concrete. Thereby, the lower end part of the construction pillar 2 is fixed by the temporary pile 20, and the construction pillar 2 penetrating the existing underground structure 10 is erected. In addition, when there is a pillar of the existing underground structure 10 at the position where the structural pillar 2 is built, first, a reinforcing PC wall (not shown) is built around the existing pillar, and then the existing pillar and The joined existing beams are disassembled by cutting them with a wire saw and lifting them, and then drilling with a casing rotary excavator (not shown).

  Next, as shown in FIG. 3, after dismantling and removing the above-described gantry, 1 of the new underground structure 1 is placed in the space formed by the dismantling process of disassembling the underground first floor portion 11 described above. A ring construction process (primary ring construction process) for constructing an annular outer ring 3 constituting the outer periphery of the floor portion is performed. The outer peripheral ring 3 is a floor slab member made of slabs and beams of the first floor portion of the new underground structure 1, and an opening 30 is formed in the central portion of the outer peripheral ring 3. In addition, since this outer periphery ring 3 is arrange | positioned in the substantially same height position as a ground line, the external force (earth pressure) applied to the outer periphery ring 3 from the mountain retaining 100 is small. Therefore, the opening 30 of the outer peripheral ring 3 is formed in a rectangular shape in plan view in consideration of various workability as shown in FIG.

Examples of the structure of the outer ring 3 include a structure composed of a steel beam and a deck slab, a structure composed of precast concrete in which a slab and a beam made of reinforced concrete are integrally formed, a steel beam or a steel reinforced concrete beam and a reinforced concrete structure. There is a structure in which the slab is integrally formed by a conventional method.
Further, as shown in FIG. 3, the outer ring 3 is supported by the true pillar 2 by joining the beam portion of the outer peripheral ring 3 to the true pillar 2 described above. At this time, an oblique beam or a cutting beam (not shown) that is slanted between the mountain stopper 100 and the outer ring 3 may be partially or temporarily installed. Thereby, a deformation | transformation of the outer periphery ring 3 can be suppressed.

  Next, as shown in FIG. 4, a dismantling process (secondary dismantling process) is performed to dismantle the underground second floor portion 12 located on the uppermost floor among the remaining existing underground structures 10. That is, the underground 1st floor beam slab 12a and the underground 2nd floor pillar wall 12b of the existing underground structure 10 are each dismantled by a known dismantling method. At this time, unillustrated heavy machinery and equipment for performing the dismantling work are lowered onto the first-floor beam slab 12a of the existing underground structure 10 from the opening 30 of the outer ring 3 described above. Moreover, the iron scrap and concrete glass generated by dismantling are lifted from the opening 30 of the outer peripheral ring 3 and carried out.

  Next, as shown in FIG. 5, an annular outer ring 4 that constitutes the outer peripheral portion of the first basement floor portion of the new underground structure 1 in the space formed by the dismantling process of the second basement floor portion 12 described above. The ring construction process (secondary ring construction process) is performed. The outer peripheral ring 4 is a floor slab member made of a slab and a beam of the first underground portion of the new underground structure 1, and an opening 40 is formed in the central portion of the outer peripheral ring 4. The opening 40 is formed in a position that is substantially the same size as the opening 30 of the outer peripheral ring 3 of the first floor portion described above and overlaps in plan view. Further, since the outer peripheral ring 4 is disposed at a position below the ground line, a certain amount of external force (earth pressure) is applied from the mountain stopper 100 to the outer peripheral ring 4. Therefore, as shown in FIG. 1, the opening 40 of the outer ring 4 is generally formed in a rectangular shape in plan view, and a haunch 41 is formed in the corner of the rectangular shape. ).

In addition, the outer periphery ring 4 of the above-mentioned first-floor part can be made into various structures like the above-described outer-periphery ring 3 of the first floor part. Further, as shown in FIG. 5, the outer ring 4 in the above-described first-floor portion is supported by the above-described construction pillar 2 in the same manner as the outer-ring 3 in the first-floor portion.
Further, materials, equipment, and the like for constructing the outer peripheral ring 4 of the first basement floor part are lowered onto the second basement beam slab 13a of the existing underground structure 10 from the opening 30 of the outer peripheral ring 3 described above.
In addition, after the outer peripheral ring 4 of the first basement floor portion is built, the column wall 32 of the first basement floor portion of the new underground structure 1 is built. At this time, reinforcing bars (not shown) are arranged around the first basement portion of the structural pillar 2 and the outer concrete 21 is placed to finish the first basement portion of the structural pillar 2.

  Next, as shown in FIG. 6, a dismantling process (tertiary dismantling process) for disassembling the underground third floor portion 13 located on the uppermost floor among the remaining existing underground structures 10 is performed. That is, the underground second-floor beam slab 13a and the underground third-floor column wall 13b of the existing underground structure 10 are each dismantled by a known dismantling method. At this time, unillustrated heavy machinery and equipment for performing the dismantling work are lowered onto the underground second-floor beam slab 13a of the existing underground structure 10 from the openings 30, 40 of the outer peripheral rings 3, 4. Moreover, the iron scraps and concrete glass generated by dismantling are lifted from the openings 30 and 40 of the outer peripheral rings 3 and 4 and carried out.

  Next, as shown in FIG. 7, an annular outer ring 5 that constitutes the outer peripheral portion of the second basement floor portion of the new underground structure 1 in the space formed by the dismantling process of the third basement floor portion 13 described above. The ring construction process (tertiary ring construction process) is performed. The outer peripheral ring 5 is a floor slab member made of slabs and beams of the second basement portion of the new underground structure 1, and an opening 50 is formed in the central portion of the outer peripheral ring 5. The opening 50 is formed to be substantially the same size as the openings 30 and 40 of the outer peripheral rings 3 and 4 of the first-floor portion and the first-floor first-floor portion, and is formed at a position overlapping in plan view. Further, since the outer ring 5 is disposed at a position further lower than the outer ring 4 in the first basement portion, the external force (earth pressure) applied to the outer ring 5 from the retaining ring 100 is the outer ring 4 in the first basement portion. Bigger than. Therefore, as shown in FIG. 1, the opening 50 of the outer ring 5 is generally formed in a rectangular shape in plan view, and is larger at the rectangular corner than the haunch 41 of the outer ring 4 of the first basement portion. A haunch 51 is formed and is formed in a polygonal shape (octagonal shape) in plan view.

In addition, the outer periphery ring 5 of the above-described second-floor portion can have various structures in the same manner as the above-described outer-rings 3 and 4 of the first-floor portion and the first-floor portion. Further, as shown in FIG. 7, the outer ring 5 of the above-described second-floor portion is supported by the above-described construction pillar 2 in the same manner as the outer-rings 3 and 4 of the first-floor portion and the first-floor portion. .
In addition, materials, equipment, and the like for constructing the outer peripheral ring 5 of the second basement part are lowered onto the third basement beam slab 14a of the existing underground structure 10 from the openings 30 and 40 of the outer peripheral rings 3 and 4 described above.
In addition, after the outer ring 5 of the second basement is built, the column wall 42 of the second basement of the new underground structure 1 is built. At this time, reinforcing bars (not shown) are arranged around the second basement floor portion of the structural pillar 2 and the outer concrete 22 is placed to finish the second basement floor portion of the structural pillar 2.

  Next, as shown in FIG. 8, a dismantling process (fourth dismantling process) for disassembling the lowermost fourth-floor portion 14 of the lowermost floor of the existing underground structure 10 is performed. That is, the underground third-story beam slab 14a and the fourth-story pillar wall 14b of the existing underground structure 10 are each dismantled by a known dismantling method. At this time, unillustrated heavy machinery and equipment for performing the dismantling work are lowered onto the underground third-floor beam slab 14a of the existing underground structure 10 through the openings 30, 40, 50 of the outer peripheral rings 3, 4, 5 described above. In addition, iron scrap and concrete glass generated by dismantling are lifted and carried out from the openings 30, 40, 50 of the outer peripheral rings 3, 4, 5 described above.

  Next, as shown in FIG. 9, an annular outer ring 6 that constitutes the outer peripheral part of the third basement floor portion of the new underground structure 1 in the space formed by the dismantling process of the fourth basement floor portion 14 described above. The ring construction process (fourth ring construction process) is performed. The outer peripheral ring 6 is a floor slab member made of a slab and a beam of the third basement floor portion of the new underground structure 1, and an opening 60 is formed in the central portion of the outer peripheral ring 6. The opening 60 is formed to have substantially the same size as the openings 30, 40, 50 of the outer ring 3, 4, 5 of the first floor part, the first basement part, and the second basement part, and overlaps in plan view. Formed in position. Further, since the outer ring 6 is disposed at a position further below the outer ring 5 in the second basement part, the external force (earth pressure) applied to the outer ring 6 from the mountain retaining 100 is the outer ring 5 in the second basement part. Bigger than. Therefore, the opening 60 of the outer peripheral ring 6 is formed in a substantially circular shape in plan view as shown in FIG.

In addition, the outer ring 6 of the above-described third basement portion can have various structures in the same manner as the outer peripheral rings 3, 4, and 5 of the first floor portion, the first basement portion, and the second basement portion. . Further, as shown in FIG. 9, the outer ring 6 of the above-mentioned third basement portion is constructed in the same manner as the outer ring 3, 4 and 5 of the above-mentioned first floor portion, the first basement portion and the second basement portion. Supported by the main pillar 2.
Further, materials and equipment for constructing the outer ring 6 of the third basement portion are the basic slab 15 on the fourth basement floor of the existing underground structure 10 through the openings 30, 40, 50 of the outer ring 3, 4, 5 described above. Take it down.
In addition, after the outer ring 6 in the third basement is built, the column wall 52 in the third basement of the new underground structure 1 is built. At this time, reinforcing bars (not shown) are arranged around the third basement floor portion of the structural pillar 2 and the outer peripheral concrete 23 is placed to finish the third basement portion of the structural pillar 2.

  Next, as shown in FIG. 10, a final root cutting process is performed in which the foundation slab 15 on the fourth floor underground of the existing underground structure 10 is dismantled and final root cutting is performed to perform flooring. At this time, heavy machinery and equipment (not shown) that perform dismantling work and root cutting work from the above-described openings 30, 40, 50, and 60 of the outer ring 3, 4, 5, 6, and the foundation of the fourth basement floor of the existing underground structure 10 Lower on slab 15. In addition, iron scrap and concrete glass generated by dismantling and earth and sand generated by root cutting are lifted and carried out from the openings 30, 40, 50, 60 of the outer peripheral rings 3, 4, 5, 6 described above.

Next, as shown in FIG. 11, a foundation floor construction process for constructing the foundation floor 7 of the fourth basement floor of the new underground structure 1 over the entire surface on the flooring surface formed in the above-described final root cutting process. Do. Materials, equipment, etc. for constructing the foundation floor 7 are lowered onto the flooring surface from the openings 30, 40, 50, 60 of the outer peripheral rings 3, 4, 5, 6 described above.
In addition, after the foundation floor 7 is constructed, the pillar wall 62 of the fourth underground floor portion of the new underground structure 1 is constructed. At this time, reinforcing bars (not shown) are arranged around the basement 4 floor portion of the structural pillar 2 and the outer concrete 24 is placed to finish the basement 4 floor portion of the structural pillar 2.
As described above, as shown in FIG. 1, a new underground structure 1 ′ having large openings 30, 40, 50, 60 formed in the center portion in plan view is built.

  Next, as shown in FIG. 12, the center of the basement in which the central portion of the new underground structure 1 is built sequentially from the lower floor inside the openings 30, 40, 50, 60 of the outer peripheral rings 3, 4, 5, 6 on each floor. Perform the part building process. Specifically, first, a pillar beam steel frame (not shown) in the central portion of the new underground structure 1 is built. At this time, it is possible to simultaneously perform the steel frame construction of the first section of the ground portion (not shown) of the new underground structure 1. Subsequently, the beam slab 63 at the center of the third basement of the new underground structure 1 is built inside the opening 60 of the outer ring 6 of the third basement, and the column wall 64 at the center of the fourth basement is built. . Thereafter, the beam slab 53 at the center of the second basement of the new underground structure 1 is built inside the opening 50 of the outer peripheral ring 5 of the second basement, and the column wall 54 at the center of the third basement is built. Thereafter, a beam slab 43 in the center of the first basement of the new underground structure 1 is built inside the opening 40 of the outer peripheral ring 4 on the first basement, and a column wall 44 in the center of the second basement is built. Thereafter, the beam slab 33 in the center of the first floor of the new underground structure 1 is built inside the opening 30 of the outer ring 3 on the first floor, and the column wall 34 in the center of the first floor of the underground is built.

  The new underground structure 1 is completed by the above. In addition, in parallel with the above-described underground central portion building process, it is possible to perform a frame construction such as a method of building a steel frame on a ground portion (not shown) of the new underground structure 1.

  According to the construction method for the underground structure described above, the dismantling process for dismantling the portion of the remaining existing underground structure 10 located on the uppermost floor, and the outer ring 3 in the space formed by the dismantling process. By alternately performing the ring construction process of constructing 4, 5, and 6, each time the existing underground structure 10 is sequentially dismantled from the upper floor, the outer ring 3 that is the outer periphery of the new underground structure 1 Since 4, 5 and 6 are built in advance, the deformation of the retaining ring 100 is suppressed by these outer peripheral rings 3 to 6. Since the outer peripheral rings 3, 4, 5, and 6 are more reliable than the cut beams, the deformation of the retaining ring 100 can be reliably suppressed even in a large-scale underground construction with a large depth and large area. Further, since the cutting beams can be omitted or reduced, the process of installing and disassembling the cutting beams can be shortened or omitted, and the construction period can be shortened.

  In addition, the central part of the newly constructed structure is formed in a blow-off shape by the openings 30, 40, 50, 60 of the outer peripheral rings 3, 4, 5, 6 that have been constructed in advance. The center of the workplace is secured to have a height (large space) sufficient to use large heavy machinery. Thereby, a large heavy machine can be thrown into the dismantling work, and the work period of the dismantling work can be shortened. Moreover, even when the existing underground structure 10 is relatively new and has high strength, it can be easily disassembled by using a large heavy machine.

  Moreover, since sunlight is irradiated from the openings 30, 40, 50, 60 of the outer peripheral rings 3, 4, 5, 6 to the underground construction workplace, the underground construction workplace is very bright. Therefore, the lighting equipment can be reduced or omitted.

  Further, since the underground work place is ventilated by the openings 30, 40, 50, and 60 of the outer peripheral rings 3, 4, 5, and 6, exhaust gas from heavy machinery is unlikely to collect in the underground work place. Therefore, ventilation equipment can be reduced or omitted. In addition, since the work place of the underground construction can be sufficiently ventilated, a large number of large heavy machinery having a large displacement can be operated at the same time, and the work period of the dismantling work can be shortened.

  Further, since the outer ring 3, 4, 5, 6 is supported by the construction pillar 2, the support work for temporarily supporting the outer ring 3, 4, 5, 6 is omitted or reduced. Thereby, temporary cost can be reduced and the work period can be shortened.

In addition, the openings 40 and 50 of the outer ring 4 of the first basement and the outer ring 5 of the second basement are hunched at rectangular corners in plan view. 41 and 51 are formed in a polygonal shape, and the opening 60 of the outer peripheral ring 6 of the third basement floor portion is formed in a circular shape in plan view. When an external force is applied to 5 and 6, the stress is less likely to concentrate on one place and is easily dispersed. As a result, the openings 30, 40, 50, 60 of the outer ring 3, 4, 5, 6 can be formed large, and a large number of large heavy machinery can be arranged in the underground work place, thereby shortening the work period of the dismantling work. can do.
In addition, since the earth pressure increases as the depth increases, the external force applied from the pile 100 increases in the lower floor among the plurality of outer peripheral rings 3, 4, 5, 6. Therefore, in the above-described embodiment, the haunches 41 and 51 of the outer ring 4 and 5 become larger toward the lower floor, and the circular opening 60 in plan view is formed below the outer rings 4 and 5 having the haunches 41 and 51. The formed outer ring 6 is disposed. Thereby, deformation | transformation of the mountain retaining 100 can be suppressed effectively, forming the opening 30,40,50,60 of the outer periphery rings 3,4,5,6 large.

As mentioned above, although embodiment of the construction method of the underground structure which concerns on this invention was described, this invention is not limited to above-described embodiment, In the range which does not deviate from the meaning, it can change suitably.
For example, in the above-described embodiment, the construction method in the case where the existing underground structure 10 on the fourth basement floor is dismantled and a new underground structure 1 on the fourth basement floor is newly constructed has been described. The number of existing underground structures and new underground structures can be changed as appropriate.

  In the above-described embodiment, the construction method is to proceed with the ground work in parallel with the underground work, but the present invention may be a construction method for starting the ground work after the underground work is completed. The ground work may not be performed.

  Further, in the above-described embodiment, the opening 30 of the outer peripheral ring 3 of the uppermost floor portion (first floor portion) of the new underground structure 1 is formed in a rectangular shape in plan view, and the middle floor portion (underground) of the new underground structure 1 The openings 40 and 50 of the outer peripheral rings 4 and 5 of the first floor part and the second basement part) are formed in a polygonal shape in plan view having the hunches 41 and 51, and the lowermost floor part (the third basement part of the basement) ) Of the outer peripheral ring 6 is formed in a circular shape in plan view, but in the present invention, the shape of the opening of the outer peripheral ring can be appropriately changed. For example, the openings of the outer peripheral rings of a plurality of stages may be formed in a circular shape in plan view or a polygonal shape in plan view having a haunch over the entire stage, or a rectangular opening if the outer peripheral ring has a high allowable stress. It is also possible to make it.

  In the above-described embodiment, the construction pillar 2 is built before the outer ring 3 is formed, and the outer rings 3, 4, 5, and 6 are supported by the construction pillar 2. It is also possible to support the outer ring 3, 4, 5, 6 by other methods. For example, the outer rings 3, 4, 5, and 6 may be supported by diagonal members or cut beams installed obliquely between the inner surface of the mountain stopper 100 and the outer rings 3, 4, 5, and 6, or The outer peripheral rings 3, 4, 5, 6 may be supported by stud connectors protruding from 100 steel materials and fixed to the outer peripheral rings 3, 4, 5, 6.

  In addition, in the range which does not deviate from the main point of this invention, it is possible to replace suitably the component in above-mentioned embodiment with a well-known component, and you may combine the above-mentioned modification suitably.

DESCRIPTION OF SYMBOLS 1 New underground structure 2 True pillar 3, 4, 5, 6 Outer ring 10 Existing underground structure 30,40,50,60 Opening 41,51 Haunch 100 Yamazuchi

Claims (3)

A construction method of an underground structure that constructs a new underground structure while dismantling an existing underground structure,
After building a retaining ring around the existing underground structure,
A dismantling step of dismantling a part located on the uppermost floor of the remaining existing underground structure;
In the space formed by the dismantling process, a ring building process for building an outer ring that is an outer peripheral part of the new underground structure and an opening is formed in the central part;
By alternately deconstructing the existing underground structure from the upper floor while sequentially dismantling the existing underground structure from the upper floor,
After the dismantling of the existing underground structure, a method for constructing the underground structure is characterized in that a central portion of the new underground structure is built inside the opening of the outer ring. In the construction method of the underground structure according to claim 1,
Prior to the ring construction process, a structural pillar that penetrates the existing underground structure and is supported on the ground below the existing underground structure is built,
A construction method for an underground structure, wherein the outer ring is supported by the structural pillar. In the construction method of the underground structure according to claim 1 or 2,
The opening of the outer peripheral ring is formed in a polygonal shape in which a haunch is formed at a rectangular corner or a circular shape in a plan view.

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