JP6274406B2 - Construction method of new underground structure with dismantling of existing underground structure - Google Patents

Description

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

Conventionally, when a part or all of an existing building with an underground part (underground frame) is dismantled and a new building is constructed, pile work or construction on the underground frame of the existing building (hereinafter referred to as the existing underground frame) When installing heavy machinery for mountain construction, demolition work, etc., the entire interior of the existing underground structure is backfilled.
Ordinarily, when constructing an underground structure of a new building (hereinafter referred to as a new underground structure), a drilling method in which excavation is carried out with hanging beams and construction is performed upward from the lowest floor of the new underground structure, A reverse driving method in which construction is performed downward from the first floor is employed (for example, see Patent Document 1).

JP 2002-61213 A

In the dismantling of the existing underground structure, if there is a backfilling process for the entire interior of the existing underground structure and a process for unloading the backfilled soil, there is a problem that costs and a construction period are required.
In addition, in the construction of a new underground structure, when the forward striking method is adopted, there is a problem that it takes a construction period compared with the reverse striking process. On the other hand, in the construction of the new underground frame, if the reverse casting method is adopted, the construction period can be shortened compared to the forward casting method, but it is necessary to perform reinforcement joints, press-fitting of post-cast concrete, filling gaps, etc. However, there is a problem that quality control takes time and costs.
For this reason, in the construction of a new underground structure that involves the dismantling of the existing underground structure, a construction method capable of reducing costs and shortening the construction period is desired.

  Then, an object of this invention is to provide the construction method of the newly installed underground frame accompanying the dismantling of the existing underground frame which can aim at cost reduction and construction period shortening.

  In order to achieve the above-mentioned object, the construction method of a new underground structure including the dismantling of the existing underground structure according to the present invention includes a temporary wall facing the outer wall inside the outer wall of the existing underground structure over the entire layers of the existing underground structure. A backfill level located at an intermediate portion in the height direction of the existing underground frame, provided with a retaining wall in a direction intersecting with the temporary wall, filled with fluidized soil between the temporary wall and the outer wall Backfilling, and above the backfill level, remove the portion of the existing underground frame inside the temporary wall, remove the outer wall, and near the area where the outer wall was provided Providing a wall and removing the temporary wall, the temporary wall, the retaining wall, and the fluidized soil of the existing underground skeleton above the backfill level above the backfill level; Placed directly above The floor and beam of the underground structure are provided. Above the floor and beam arranged just above the backfill level, the new underground structure is constructed by a forward-acting method, and is placed just above the backfill level. Below the floor and beam, the existing underground structure is removed, and the new underground structure is constructed by a reverse driving method.

In the present invention, by providing a temporary wall and a retaining wall and filling the fluidized soil between the temporary wall and the existing outer wall, the outer periphery of the existing underground frame is reinforced, so that the existing underground frame is disassembled. Even if it is not possible to carry out mountain construction, it is possible to safely dismantle the central part (inside the outer peripheral part) of the existing underground structure. And since the backfilling may be performed up to the backfilling level located in the middle in the height direction of the existing underground skeleton, the backfilling and unloading of the backfill soil are carried out as compared with the case where the entire interior of the existing underground skeleton is backfilled. Cost and construction period can be shortened.
In addition, above the floor and beam of the newly installed underground structure located directly above the backfill level, the new underground structure will be constructed by the forward casting method, and below this, the new underground structure will be constructed by the reverse casting method. Therefore, compared with the case where the whole is constructed by the reverse casting method, it is possible to reduce the cost of the quality control and the labor of quality control such as rebar joint, press-fitting of post-cast concrete, and filling of gaps.

Moreover, in the construction method of the new underground skeleton with the dismantling of the existing underground skeleton according to the present invention, the backfill level is preferably higher than the water level.
By doing in this way, work can be performed without being affected by groundwater above the backfill level.
Moreover, in the construction method of the new underground skeleton with the dismantling of the existing underground skeleton according to the present invention, the pillars and beams are not removed from the existing underground skeleton below the backfill level. The floor slab and the inner wall may be removed and then backfilled to the backfill level.

According to the present invention, since the outer peripheral portion of the existing underground frame is reinforced by providing the temporary wall and the retaining wall and filling the fluidized soil between the temporary wall and the existing outer wall, the existing underground frame is disassembled. Even if it is not possible to perform the mountain retaining work at the time, the dismantling of the central part (the inside of the outer peripheral part) of the existing underground building can be safely performed. And since the backfilling may be performed up to the backfilling level located in the middle in the height direction of the existing underground skeleton, the backfilling and unloading of the backfill soil are carried out as compared with the case where the entire interior of the existing underground skeleton is backfilled. Cost and construction period can be shortened.
In addition, above the floor and beam of the newly installed underground structure located directly above the backfill level, the new underground structure will be constructed by the forward casting method, and below this, the new underground structure will be constructed by the reverse casting method. Therefore, compared with the case where the whole is constructed by the reverse casting method, it is possible to reduce the cost of the quality control and the labor of quality control such as rebar joint, press-fitting of post-cast concrete, and filling of gaps.

It is a figure explaining step 1 among the steps of the construction method of the new underground skeleton with the dismantling of the existing underground skeleton by embodiment of this invention. It is a figure explaining step 2 following FIG. FIG. 3 is a diagram for explaining step 3 following FIG. 2. FIG. 4 is a diagram for explaining Step 3 and Step 4 following FIG. 3. It is a figure explaining step 5 following FIG. It is a figure explaining step 6 following FIG. It is a figure explaining step 7 following FIG. It is a figure explaining step 8 following FIG. It is a figure explaining step 9 following FIG. It is a figure explaining step 10 following FIG. It is a figure explaining step 11 following FIG. It is a figure explaining step 12 following FIG. It is a figure explaining step 12 following FIG. It is a figure explaining step 12 and step 13 following FIG. It is a figure explaining step 13 following FIG. It is a figure explaining step 13 following FIG. It is a figure explaining step 13 following FIG. It is a figure explaining step 13 following FIG. It is a figure explaining step 13 following FIG.

Hereinafter, a construction method for a newly installed underground structure that involves dismantling of an existing underground structure according to an embodiment of the present invention will be described with reference to FIGS. 1 to 19.
In this embodiment, an existing building 1 having a four-story underground structure (hereinafter referred to as an existing underground structure) 11 as shown in FIG. 1 is dismantled, and a five-story underground structure (hereinafter referred to as a new structure) is disposed at substantially the same location. It is assumed that a new building 2 (see FIG. 19) having 21 (which will be an underground skeleton) is constructed. And the construction method of the newly installed underground frame accompanying the dismantling of the existing underground frame by this embodiment is employ | adopted for this demolition work and construction work.
In the present embodiment, the bottom plate 22 (see FIG. 19) of the newly constructed underground frame 21 is located below the bottom plate 12 of the existing underground frame 11.

Next, the construction method of the newly installed underground structure with the dismantling of the existing underground structure according to the present embodiment will be described step by step.
(Step 1)
First, as shown in FIG. 1, a scaffold 31 is constructed outside the existing building 1, and the interior and equipment of the existing building 1 are disassembled and removed.
At this time, when asbestos is used in the existing building 1, the asbestos is processed.

(Step 2)
Next, as shown in FIG. 2, a temporary wall 4 and a retaining wall (buttress) 5 are provided on the existing underground frame 11.
The temporary wall 4 is a wall portion provided inside the outer wall 13 of the existing underground enclosure 11 so as to face the outer wall 13 with a predetermined interval, and is provided over the entire layer (the entire height direction) of the existing underground enclosure 11. It is done.
The retaining wall 5 is a wall provided inside the existing underground enclosure 11 so as to be substantially orthogonal to the temporary wall 4 with respect to the temporary wall 4, and a plurality of the reserved walls 5 are provided at predetermined intervals in the width direction of the temporary wall 4. These retaining walls 5 are connected to the retaining wall 5 at the end on the temporary wall 4 side.
In the present embodiment, the retaining walls 5 are provided on the second and third basement floors, and the retaining wall 5 on the second underground floor is wider than the retaining wall 5 on the third underground floor (in a direction perpendicular to the temporary wall 4). (Dimensions) should be large.

  Further, in parallel with or before and after the construction of the temporary wall 4 and the retaining wall 5, the reinforcement support 32, 32... For dismantling is installed in the ground portion 14 of the existing building 1, and the dismantling of the ground portion 14 is disposed on the first floor. .. Are formed in the floor slabs 16, 16... On each floor of the ground portion 14.

(Step 3)
Next, as shown in FIG. 3, fluidized soil 6 is filled between the outer wall 13 and the temporary wall 4 of the existing underground enclosure 11.
At this time, the fluidized soil 6 is filled between the outer wall 13 and the temporary wall 4 to construct the wall body 7 having the outer wall 13, the temporary wall 4, the retaining wall 5, and the fluidized soil 6 of the existing underground enclosure 11. .
In parallel with the construction of the wall body 7, the ground portion 14 is disassembled and removed.

(Step 4)
Subsequently, as shown in FIGS. 3 and 4, backfilling is performed inside the wall body 7.
In this embodiment, backfilling is performed up to the level of the water level. In the present embodiment, the water level is GL-10.5 m, and the water level is located between the floor slab 16c on the third basement floor of the existing building 1 and the slab 16b on the second basement floor. In the new building 2, this water level is located between the floor slab 25 c on the third basement floor and the slab 25 b on the second basement floor (see FIG. 16).
Here, the height (water level) which becomes the upper surface of the backfill will be described as a backfill level 10 below.
First, the floor slab 16d (see FIG. 2) on the fourth basement floor is disassembled and backfilled from the upper part of the bottom plate 12 to a height corresponding to the upper surface of the floor slab 16a as shown in FIG.

Subsequently, as shown in FIG. 4, backfilling up to a backfill level 10 is performed. At this time, the pillars, beams and the like of the existing underground skeleton 11 below the backfill level 10 are not dismantled and are buried in the backfill soil 17. In addition, the floor slab 16c of the existing underground skeleton 11 below the backfill level 10 is dismantled inside leaving the outer periphery, and the inner wall is almost dismantled and removed.
In the present embodiment, a demolition glass is used as the backfill soil 17. For this reason, the openings 15B are also formed in the floor slabs 16a to 16c from the first basement floor to the third basement floor and the floor slab 16e on the first floor so that the dismantling of the ground portion 14 can be dropped underground.
In parallel with this backfilling, the ground portion 14 is disassembled and removed.

(Step 5)
Subsequently, as shown in FIG. 5, dismantling of the inner side of the wall body 7 is performed in the upper part of the backfill level 10 in the existing underground skeleton 11. Note that the buttress wall 5 is left without being dismantled.
In this embodiment, this disassembly is performed after the disassembly of the ground portion 14 is completed.

(Step 6)
Subsequently, as shown in FIG. 6, the gantry 8 is constructed inside the wall body 7 at the upper portion of the backfill level 10.
The gantry 8 includes a column 81 standing on the upper portion of the backfill soil 17 and a beam member 82 installed between the columns 81, and a floor material or a brace as a work floor is provided as necessary. Yes.
The upper end of the gantry 8 has substantially the same height as the GL.
The gantry 8 is constructed so that the central portion 83 and the outer peripheral portion 84 can be separated in order to remove the inner central portion 83 prior to the outer peripheral portion 84 on the wall body 7 side in step 7 described later.

(Step 7)
Subsequently, as shown in FIG. 7, the outer wall 13 (see FIG. 6) of the existing underground frame 11 is disassembled, and the mountain retaining wall 9 is provided at a position substantially the same as the position where the outer wall 13 was located.
The disassembly of the outer wall 13 is performed using, for example, a CD. In addition, the fluidized soil 6 is partially dismantled as necessary.
The mountain retaining wall 9 is constructed by, for example, a soil cement method.

(Step 8)
Subsequently, as shown in FIG. 8, a pile of the new building 2 and a built-up pillar 24 that becomes a pillar below the backfill level 10 are placed.
First, the central portion 83 (see FIG. 7) of the gantry 8 is removed, a heavy machine is installed on the backfilling soil 17, and the structural pillar 24 is driven.
In the present embodiment, the structural pillar 24 is placed so that the upper end thereof is substantially the same height as the backfill level 10.

(Step 9)
Subsequently, as shown in FIG. 9, the outer peripheral portion 84 (see FIG. 8) of the gantry 8 is disassembled, and the temporary wall 4 and the fluidized soil 6 provided on the first basement floor of the existing underground enclosure 11 are disassembled and removed. .

(Step 10)
Subsequently, as shown in FIG. 10, the steel frame 23 of the newly installed underground frame 21 is constructed above the backfill level 10.
At this time, the remaining temporary wall 4, the retaining wall 5, and the portion that interferes with the fluidized soil 6 are constructed after dismantling and removing them in step 10 described later.

(Step 11)
Subsequently, as shown in FIG. 11, the concrete 23 of the floor slab 25 f on the first floor of the new building 2 is placed, and the temporary wall 4, the retaining wall 5, and the fluidized soil 6 are disposed above the backfill level 10. Is dismantled and removed.

(Step 12)
Subsequently, as shown in FIGS. 12 to 14, concrete is placed in the new underground skeleton 21 above the backfill level 10 of the new building 2.
First, as shown in FIG. 12, the concrete of the floor slab 25b and the beam 26c on the second basement floor is placed, and the concrete of the pillar 27b and the wall 28b on the second basement floor is placed as shown in FIG. Subsequently, the concrete of the floor slab 25a and the beam 26b on the first basement floor is placed, and the concrete of the pillar 27a and the wall 28a on the first basement floor is placed as shown in FIG.
The concrete placement of the floor slab 25b, the beam 26c, the column 27b, and the wall 28b on the second basement floor may be performed simultaneously.

(Step 13)
Subsequently, as shown in FIGS. 14 to 19 , the new underground structure 21 is constructed by the reverse driving method while dismantling the existing underground structure 11 below the floor slab 25 b on the second floor below the backfill level 10. To do.
First, as shown in FIG. 14, the backfill soil 17 is removed to a height below the height at which the floor slab 25 c (see FIG. 15) on the third basement floor of the new building 2 is provided, and the backfill soil 17 is removed. The housing of the existing building 1, the temporary wall 4 and the fluidized soil 6 (see FIG. 13) exposed by the above are dismantled and removed.

Subsequently, as shown in FIG. 15, the floor slab 25c and the beam 26d on the third basement floor of the new building 2 are constructed. Then, the pillar 27c and the wall 28c on the third basement floor of the new building 2 are constructed.
Subsequently, the backfill soil 17 disposed in the central portion of the existing underground frame 11 is removed from the remaining backfill soil 17, and the central portion 12 a (see FIG. 14) of the bottom plate 12 of the existing building 1 is disassembled and removed. Do. Thereby, the backfill soil 17 and the bottom board 12 are in a state where only the outer peripheral portion 12b is left.
And as shown in FIG. 16, the construction of the floor slab 25d and the beam 26e on the fourth basement floor of the new building 2 is performed.
Subsequently, the backfill 17 shown in FIG. 15 and the outer peripheral portion 12b of the bottom plate 12 are disassembled, and as shown in FIG. 16, these are removed.

Subsequently, the pillar 27d and the wall 28d on the fourth basement floor of the new building 2 are constructed.
Subsequently, excavation (root cutting work) below the floor slab 25d and the beam 26e on the fourth basement floor of the new building 2 is performed. At this time, excavation is performed on portions corresponding to the floor slab 25e on the fifth basement floor of the new building 2 and the central portions 25ea and 22a of the bottom panel 22 of the new building 2.

Subsequently, as shown in FIG. 17, the floor slab 25e on the fifth basement floor of the new building 2 and the central portions 25ea and 22a of the bottom board 22 of the new building 2 are constructed. Thereafter, the floor slab 25e on the fifth basement floor of the new building 2 and the portions corresponding to the outer peripheral portions 25eb and 22b of the bottom board 22 of the new building 2 are excavated, and as shown in FIG. 18, the floor slab 25e on the fifth basement floor and The outer peripheral portions 25eb and 22b of the bottom board 22 of the new building 2 are constructed.
Then, as shown in FIG. 19, the construction of the pillar 27e and the wall 28e on the fifth basement floor is performed.
In this way, the newly installed underground structure 21 is constructed.
In parallel with step 13, the ground portion of the new building 2 is also constructed.

Next, the operation and effect of the construction method for the newly installed underground structure accompanied by the dismantling of the existing underground structure will be described with reference to the drawings.
In the construction method of the newly installed underground frame with the dismantling of the existing underground frame according to the present embodiment, the temporary wall 4 and the retaining wall 5 are provided, and the fluidized soil is filled between the temporary wall 4 and the outer wall 13, thereby Since the outer periphery of the underground skeleton 11 is reinforced, even if the mountain retaining work cannot be performed when the existing underground skeleton 11 is dismantled, it is safe to dismantle the central portion (inside the outer periphery) of the existing underground skeleton 11 Can be done. And since backfilling should just be performed to the backfill level 10 located in the intermediate part of the height direction of the existing underground skeleton 11, it is backfilled and backfilled compared with the case where the whole inside of the existing underground skeleton 11 is backfilled. The cost for carrying out the soil 17 can be reduced and the construction period can be shortened.
In addition, the new underground skeleton 21 is constructed by a forward construction method above the floor slab 25b on the second basement floor and the beam 26c on the third basement floor of the new underground skeleton 21 arranged immediately above the backfill level 10. In the lower part, since the construction of the newly installed underground frame 21 is performed by the reverse casting method, compared to the case where the entire newly installed underground frame 21 is constructed by the reversed casting method, the reinforcement joints, the press-fitting of the post-cast concrete, the filling of the gap, etc. It is possible to reduce the labor of quality control and to reduce costs.

As mentioned above, although the embodiment of the construction method of the new underground structure accompanying the dismantling of the existing underground structure by this invention was described, this invention is not limited to said embodiment, It changes suitably in the range which does not deviate from the meaning. Is possible.
For example, the shape such as the number of floors of the existing building 1 or the new building 2 may be set as appropriate.
In the above embodiment, the retaining wall 5 has a different width dimension depending on the floor provided, but may have the same width dimension.
Moreover, in said embodiment, although the demolition glass is used for the backfill soil 17, you may use other than the demolition glass.
In the above embodiment, the mountain retaining wall 9 is constructed of soil cement. However, the mountain retaining wall 9 made of a sheet pile or the like may be used.
Moreover, the process of dismantling the ground part 14 of the existing building 1 and the process of constructing the ground part of the new building 2 may be set as appropriate.
Moreover, when constructing the newly installed underground skeleton 21, a cut beam or an oblique beam may be provided as necessary.

DESCRIPTION OF SYMBOLS 1 Existing building 2 New building 4 Temporary wall 5 Reservation wall 6 Fluidized soil 7 Wall body 9 Mountain wall 10 Refill level 11 Existing underground frame 12 Bottom board 13 Outer wall 14 Above-ground part 16 Floor slab 17 Backfill soil 21 New underground frame 22 Bottom 25 Floor Slab 26 Beam

Claims (3)

Provided a temporary wall facing the outer wall on the inner side of the outer wall of the existing underground skeleton over all layers of the existing underground skeleton, and provided a retaining wall in a direction intersecting with the temporary wall,
Filling the fluidized soil between the temporary wall and the outer wall,
Backfill to the backfill level located in the middle of the height direction of the existing underground structure,
Above the backfill level, remove the portion of the existing underground enclosure inside the temporary wall,
Removing the outer wall and providing a mountain retaining wall near the area where the outer wall was provided,
Above the backfill level, removing the portion of the existing underground skeleton outside the temporary wall, the temporary wall, the retaining wall, and the fluidized soil,
Providing a floor and a beam of a newly installed underground structure arranged just above the backfill level;
Above the floor and beams arranged just above the backfill level, the construction of the new underground structure is carried out by a forward casting method,
Dismantling of the existing underground structure, wherein the existing underground structure is removed by a reverse driving method and the existing underground structure is removed below the floor and beams arranged immediately above the backfill level. Construction method of the new underground frame with a   The method for constructing a new underground structure according to claim 1, wherein the backfill level is above the water level.   Of the existing underground structure below the backfill level, without removing pillars and beams, floor slabs and inner walls other than the outer periphery are removed and then backfilled to the backfill level. The construction method of the newly installed underground frame according to claim 1 or 2.

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