JP3724320B2 - Construction method for underground structures - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, a main structure is a steel reinforced concrete structure (hereinafter referred to as “SRC structure”) or a steel structure (hereinafter referred to as “S structure”) while dismantling the existing underground structure in a site where the existing underground structure is built. It is related to the construction method of the underground structure that newly constructs the underground structure consisting of
[0002]
[Prior art]
As a method of dismantling an existing underground structure and then constructing a new underground structure whose main structure is an SRC structure or S structure, a retaining wall has been previously constructed on the outer periphery of the underground structure so far. While supporting the mountain retaining wall with the earth anchor, dismantle the existing underground structure first, dig the ground to a predetermined depth, build the foundation, and assemble the steel frame of the underground structure on this foundation, In general, a method of newly constructing a housing in order from the top to the bottom is performed.
[0003]
[Problems to be solved by the invention]
However, with the above method, for example, if the retaining wall is supported by a cut beam, the cut beam will be spanned in multiple stages, and the shelf pile supporting the cut beam will be forested. He was forced to dig, and the work efficiency was very poor.
[0004]
As another method for supporting the retaining wall, the earth anchor method is also known. However, in recent construction work in urban areas, it is often impossible to use an earth anchor outside the site due to the proximity of the adjacent land. .
In addition, there is a reverse casting method in which the main floor is used as a support for the retaining wall and work floor without using beams and earth anchors, and the basement is dug into the basement while building from the upper floor to the basement. As is known, it is necessary to install a construction pillar that supports the main floor in advance, and this construction pillar must be installed through the frame of an existing structure. There were problems such as a long construction period and construction costs.
[0005]
The present invention has been made to solve the above-described problems. When a new underground structure whose main structure is an SRC structure or an S structure is newly constructed in a site where an existing underground structure is built, To provide a method for constructing an underground structure that can be used from the dismantling of an existing underground structure to the construction of a new underground structure, without the use of timber support works such as beams. Is an issue.
[0006]
[Means for Solving the Problems]
The construction method of the underground structure according to claim 1 is a construction method of an underground structure for constructing a new underground structure of the same scale as the existing underground structure in a site where the existing underground structure is demolished, After constructing a retaining wall on the outer periphery of the existing underground structure, disassemble the entire outer peripheral part of the existing underground structure and the first underground floor of the central part, and then to the supporting ground on the outer peripheral part of the existing underground structure Build the structural pillar to reach and support the structural pillar and the retaining wall to construct the surrounding floor of the ground floor of the newly installed underground structure, the central part of the existing underground structure to the lowest floor Dismantled, and then build the steel frame of the central part of the newly installed underground structure in order from the lowest floor to the highest floor, and between the uppermost floor of the central part of the newly installed underground structure and the surrounding floor on the ground floor A steel beam between them, and then the existing structure Sequentially dismantle the perimeter from the second basement to the bottom floor, then build the floor of each floor of the outer periphery of the newly built underground structure sequentially from the second basement to the bottom floor, and the surrounding floor and central part of each floor It is characterized by bridging steel beams between each floor.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1-5 shows an example of the construction method of the underground structure based on this invention, and demonstrates a construction method later on in order.
[0009]
(1) First, a mountain retaining wall 2 is constructed around an existing underground structure 1 (hereinafter referred to as “existing underground structure”) (see FIG. 1 (1)). The retaining wall 2 is constructed to support the surrounding earth pressure until the existing underground structure 1 is demolished and then a new underground structure (hereinafter referred to as “new underground structure”) is constructed. For example, it is constructed by a continuous mountain fastening method.
[0010]
(2) Next, the underground first floor portion B1F of the existing underground structure 1 is dismantled over the entire central portion A and outer peripheral portion B (see FIGS. 1 (2) and (3)). This dismantling work shall be carried out with heavy machinery that has been generally used so far.
[0011]
(3) Next, for the central part A of the existing underground structure 1, the dismantling work is continued with the second basement part B2F and the third basement part B3F, and dismantling to the lowest floor (Fig. 1 (4), (See Fig. 2 (1)). On the other hand, in the outer peripheral part B of the existing underground structure 1, the construction pillar 3 is constructed on the floor of the first basement part B1F (see FIG. 1 (4)).
[0012]
The structural pillar 3 works as a temporary pillar until the existing underground structure 1 is demolished and then a new underground structure to be described later is constructed. Further, depending on the construction method, the structural pillar 3 can also be a pillar of the new underground structure. It is.
[0013]
Therefore, the structural pillar 3 is raised up to the floor portion of the first floor above the ground, and penetrates the floor of the underground first floor portion B1F of the existing underground structure 1 and the floors of all the floors below it, and surely reaches the supporting ground. For example, it is constructed by the all-swivel all-casing method.
[0014]
The reason why the outer peripheral portion B is particularly left until the central portion A of the existing underground structure 1 is dismantled is to use the outer peripheral portion B as a support for supporting the retaining wall 2.
[0015]
Therefore, while dismantling the central portion A, the width of the outer peripheral portion B to be left is determined by the depth of the existing underground structure 1 and the ground conditions of the site where the existing underground structure 1 is constructed. In the figure, one span of the existing underground structure 1 is left as a support for the retaining wall 2.
[0016]
(4) Next, the floor 4A on the ground floor is constructed in the outer peripheral portion B (see FIG. 2 (4)). This floor 4A is used as a work floor for performing the subsequent work, and is constructed by supporting the surrounding retaining wall 2 and the structural pillar 3. Further, the floor 4A also becomes a floor of the first floor part of the newly installed underground structure to be constructed later depending on the construction method.
[0017]
(5) Next, when the dismantling of the central portion A proceeds to the lowest floor, the lower ground is further dug down to a predetermined depth to form a root-cutting ground surface 5 (see FIG. 3 (3)). It should be noted that in this root cutting work, slopes 6 are provided in the surrounding area in order to prevent the occurrence of accidents such as collapse of natural grounds and to ensure work safety.
[0018]
(6) Next, the foundation 7 of the newly installed underground structure is constructed on the root cutting ground surface 5 (see Fig. 3 (3)), and the steel frame 8 of the newly installed underground structure is placed on it from the lowest floor. Assemble sequentially to the top floor (see Fig. 3 (3)). Then, the steel beam 9A is bridged between the steel beam 8a on the top floor and the surrounding floor 4.
[0019]
The steel beam 9A functions as a cutting beam that supports the retaining wall 2 until the outer peripheral portion B of the existing underground structure 1 is dismantled, and depending on the construction method, the uppermost floor of the steel frame 8 It is left as a steel beam.
[0020]
(7) Next, disassemble the outer peripheral part B of the existing underground structure 1 into the second basement part B2F, the third basement part B3F, and the upper floor in order (Figs. 3 (1), (2), (See (3)). In particular, floors 4B, 4C, and 4D that function in the same manner as floor 4A are constructed after dismantling each floor. Further, steel beams 9B, 9C, 9D having the same function as the steel beam 9A are bridged between the floors 4B, 4C, 4D of each floor and the steel frame 8 (FIGS. 3 (1), (2), (See (3)).
[0021]
In addition, if the steel beams 9A, 9B, 9C, and 9D are acted as cutting beams, the cross section of each steel beam may become large and may be extremely uneconomical. Therefore, the steel beams 9A, 9B, 9C, and 9D are replaced. Alternatively, the concrete floors 10A, 10B, 10C, and 10D may be constructed, and the concrete floors 10A, 10B, 10C, and 10D may be used as a beam.
[0022]
(8) When the dismantling of the outer peripheral part B of the existing underground structure 1 is completed up to the lowest floor in this way, the lower ground is further dug down to the root section 5 of the central part (see Fig. 4 (1)), After that, the foundation 7 of the new underground structure is constructed integrally with the foundation 7 of the central portion A (see FIG. 4 (2)). It should be noted that the slope 6 is provided in the periphery in order to prevent the occurrence of a collapse of a natural ground and the safety of the work in the root cutting work of the outer peripheral portion B.
[0023]
Through the above process, the process from the dismantling of the existing underground structure 1 to the construction of the new underground structure (steel frame 8) can be continued very efficiently and economically without the need for special support work such as beams. Can be done.
[0024]
【The invention's effect】
The present invention is as described above, and by leaving the outer peripheral portion of the existing underground structure and using it as a support for the retaining wall until the outer peripheral portion of the existing underground structure is dismantled, It is possible to omit the supporting work such as a cut beam and a ground anchor which are necessary for supporting the retaining wall.
[0025]
Therefore, the dismantling of the main part of the existing underground structure and the excavation work under the main part can be efficiently performed, and the construction period can be shortened and the construction cost can be reduced.
[0026]
Moreover, about the range which leaves as a support body of a retaining wall and is demolished later, it is not necessary to provide a large-scale work table by constructing a work floor at the first floor level at an early stage by the reverse driving method. In addition, the upper frame work in the central part can be carried out simultaneously with the underground work, and the construction period can be shortened.
[0027]
In this way, when constructing a new underground structure while dismantling the existing underground structure, by effectively using the existing underground structure, which is originally an obstacle to the construction, instead of the temporary mountain retaining material, demolition work, excavation work, Underground building construction can be carried out efficiently, shortening the construction period and reducing temporary construction costs.
[Brief description of the drawings]
FIG. 1 (1) to (4) are process diagrams showing from the construction of a retaining wall to the construction of a structural pillar.
FIG. 2 (1) to (4) are process diagrams showing from the dismantling of the central part to the construction of the foundation.
FIGS. 3 (1) to (3) are process diagrams showing the process from assembling the steel frame of the newly-constructed structure to disassembling the outer peripheral portion.
FIGS. 4A and 4B are process diagrams showing from the root cutting of the outer peripheral portion to the construction of the foundation.
FIG. 5 is a plan view showing an arrangement example of a retaining wall and a true pillar.
[Explanation of symbols]
1 Existing underground structure (existing underground structure)
2 Mountain retaining wall 3 True column 4A Floor 4B Floor 4C Floor 4D Floor 5 Root cut ground surface 6 Slope 7 Foundation 8 Steel frame 8a Steel beam 9A Steel beam 9B Steel beam 9C Steel beam 9D Steel beam
10A concrete floor
10B Concrete floor
10C concrete floor
10D concrete floor

Claims (1)

An underground structure construction method for constructing a new underground structure of the same scale as the existing underground structure on the site where the existing underground structure has been demolished, and after building a retaining wall on the outer periphery of the existing underground structure , Dismantling the entire outer peripheral part and central part of the existing underground structure, and then constructing a structural pillar that reaches the supporting ground at the outer peripheral part of the existing underground structure, and The surrounding floor of the ground floor of the new underground structure is constructed by supporting the pillar and the retaining wall, the central part of the existing underground structure is demolished to the lowest floor, and then the central part of the new underground structure is A steel frame is constructed in order from the lowest floor to the highest floor, and a steel beam is bridged between the uppermost floor of the central part of the new underground structure and the surrounding floor of the first floor above the ground, and then the existing structure In order from the second floor of the basement to the lowest floor After dismantling, the floor of each floor of the newly constructed underground structure is constructed sequentially from the second basement floor to the lowest floor, and steel beams are bridged between the surrounding floor of each floor and each floor of the central part Construction method for underground structures.

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