JP2018076693A - Building reconstruction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a building reconstruction method that can reconstruct buildings in a short construction period while reducing construction costs.SOLUTION: The building reconstruction method is a method of constructing a new underground skeleton after demolishing an existing underground skeleton 2. The building reconstruction method includes the steps of demolishing the existing underground skeleton 2 to form an underground space 21 (S2), disposing an excavator 22 on the bottom surface of the underground space 21 and driving a new pile 24 on the foundation below the underground space 21 using the excavator 22 (S3 and S4), and constructing a new underground skeleton on the new pile 24 (S5).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a building rebuilding method for constructing a new underground structure after dismantling an existing underground structure.

Conventionally, after dismantling an existing underground structure having an underground structure, a new underground structure having a pile in the same place may be constructed.
In this case, the existing underground structure is dismantled while erection support works for dismantling are built, and then the earth and sand are backfilled in the underground space formed by the dismantling of the existing underground structure to the vicinity of the ground surface. Next, a pile driver is placed on the backfilled earth and sand, and a pile for a new building is driven. Next, excavation will be carried out while erection support works for the new underground structure are being built. After that, the new underground structure will be constructed from the lower layer to the upper layer, while dismantling the retaining structure for the new underground structure.

Here, as a method of constructing a pile of a newly installed underground frame, there are the following methods.
Patent Literature 1 discloses a concrete pile burying method. First, a press-fitting device capable of press-fitting concrete piles is installed on the ground. Next, this press-fitting device is provided with a support mechanism for supporting the excavation device suspended from the wire of the crane, and the press-fitting operation of the concrete pile and the excavation operation of the excavation device are selected and performed.

  Patent Document 2 discloses a method for removing an existing underground outer wall. In other words, while excavating the outer periphery of the interference part where the existing underground outer wall interferes with the construction pillar of the new building, a semicircular retaining wall is constructed, and the outer peripheral surface of the interference part of the existing underground outer wall is exposed. In this state, the interference part of the existing underground wall is cut and removed by the wire saw method. After that, a construction pillar is built at the position where the interference part is removed.

  Patent Document 3 discloses a pile construction method. First, by rotating the cylindrical jig main body against the pile press-fitted into the ground, the protruding member fixed to the pile is fitted into the insertion groove of the jig main body, and the jig main body is It can be rotated and press-fitted together with the pile. Next, rotate the jig body in the ground to press-fit the pile and jig body into the ground, and rotate the jig body in the opposite direction to remove the jig body from the pile and remove the jig body. Remove from the ground.

  Patent Document 4 discloses a building construction method for constructing a new building using an existing building. First, after installing the work gantry on the first floor slab of the existing building, next, form openings in all the existing underground slabs on the basement floor of the existing building, and through the openings, the lowest basement floor of the existing building Construction materials will be suspended from the bottom floor of the basement floor until the construction materials are suspended.

JP 2012-219574 A JP2015-124540A JP 2010-242405 A Japanese Patent No. 5925231

  This invention makes it a subject to provide the building rebuilding method which does not require a backfill.

  As a method of rebuilding an existing building that does not require backfilling, the present inventors dismantle the existing underground structure by constructing a new pile for the new building from the ground under the existing foundation that has dismantled the existing underground structure. Then, focusing on the point that a new pile for a new building can be constructed without refilling the earth and sand in the dismantled portion, and an underground building of the new building can be constructed on the pile, the present invention has been achieved.

  A building rebuilding method according to a first aspect of the present invention is a building rebuilding method in which a new underground building is constructed after dismantling an existing underground building (for example, an existing underground building 2 described later), and the existing underground building is dismantled. A step of forming an underground space (for example, a below-described underground space 21) (for example, step S2 to be described later), and an excavator (for example, an excavator 22 to be described later) on the bottom surface of the underground space, A process of placing a new pile (for example, a new pile 24 described later) on the ground below the underground space using an excavator (for example, steps S3 and S4 described later), and a new underground on the new pile And a step of constructing a housing (for example, step S5 described later).

  According to this invention, the pile driver is placed on the bottom surface of the underground space formed by dismantling the existing underground frame, and the new pile is driven on the bottom surface of the underground space. There is no need to refill the underground space after dismantling the underground structure, dismantle the mountain retaining support for dismantling, excavating to build a new underground structure, and constructing the retaining structure for the new underground structure Therefore, it is possible to rebuild the building in a short construction period while reducing the construction cost.

  In the building rebuilding method according to a second aspect of the present invention, the pile driving machine is a rotary excavator with a low head, and in the step of placing the new pile, the ground below the underground space is used by using the rotary excavator. After a pile hole is formed in the pile hole, a new pile is driven into the pile hole.

Since the pile retaining machine is installed in the underground space, if a pile driving machine is placed on the bottom of the underground space, when the pile is built directly under the beam of the mountain retaining work, the kelly bar of the pile driving machine is used as the cutting beam. In some cases, the piles could not be driven due to interference.
So, according to this invention, the low excavation rotary excavator was used as a pile driver. The low excavation rotary excavator rotates the boring rod attached to the boring machine for excavation, so the height required for pile driving work is reduced, and the pile can be built smoothly even directly under the beam. it can. First, pile holes are formed with a rotary excavator, and new piles are driven into the pile holes, so that piles with various diameter sizes can be constructed.

  The building rebuilding method of the third invention is a new mountain retaining wall (e.g., described later) along the existing underground outer wall (e.g., existing underground outer wall 17 described later) of the existing underground frame before dismantling the existing underground building. (For example, step S1 to be described later), and in the step of dismantling the existing underground structure, a beam (for example, between the newly installed retaining walls facing each other) In the step of constructing a later-described cut beam 32) and constructing the new underground structure, the cut beam is dismantled.

  According to the present invention, since the newly installed mountain retaining wall is constructed along the existing underground outer wall of the existing underground frame, the axial rigidity of the mountain retaining wall can be increased. In addition, since the cut beams built between the new retaining walls can be used both when dismantling the existing underground structure and when constructing the new underground structure, the building can be rebuilt in a short construction period while reducing construction costs. .

  According to the present invention, by constructing a new pile for a new building from the ground below the foundation that dismantled the existing underground frame, and constructing the underground frame of the new building on the new pile, an existing building that does not require backfilling Realized the rebuilding method of the building. Therefore, it is possible to rebuild the building in a short construction period.

1 is a longitudinal sectional view of an existing building 1 to which a building rebuilding method according to a first embodiment of the present invention is applied. It is a flowchart of the procedure of demolishing an existing building and constructing a new building by the building rebuilding method according to the embodiment. It is explanatory drawing (the 1 and a longitudinal cross-sectional view of the existing underground frame in the state where the mountain retaining wall was constructed) which demolishes the existing building by the building rebuilding method which concerns on the said embodiment, and constructs a new building. It is explanatory drawing (the 2 and the longitudinal cross-sectional view of the state which disassembled the existing underground skeleton) the procedure which demolishes the existing building by the building rebuilding method which concerns on the said embodiment, and constructs a new building. It is explanatory drawing (the 3rd, top view of the state which disassembled the existing underground skeleton) the procedure which demolishes the existing building by the building reconstruction method which concerns on the said embodiment, and constructs a new building. It is explanatory drawing (the longitudinal cross-sectional view of the state which disassembled the existing underground frame) of the procedure which demolishes the existing building and constructs a new building by the building rebuilding method which concerns on 2nd Embodiment of this invention. It is explanatory drawing (plan view of the state which disassembled the existing underground building) of the procedure which demolishes the existing building by the building reconstruction method which concerns on the 1st modification of this invention, and constructs a new building. In explanatory drawing (the 1 and the longitudinal cross-sectional view of the existing underground frame in the state where the retaining wall was erected) in the procedure of constructing a new building by demolishing the existing building by the building rebuilding method according to the second modification of the present invention is there. It is explanatory drawing (the 2 and top view of the state which disassembled the existing underground skeleton) of the procedure which demolishes the existing building and constructs a new building by the building rebuilding method which concerns on the 2nd modification of this invention. It is explanatory drawing (the 3 and a longitudinal cross-sectional view of the state which disassembled the existing underground frame) of the procedure which demolishes an existing building and constructs a new building by the building rebuilding method which concerns on the 2nd modification of this invention. It is explanatory drawing (plan view of the state which disassembled the existing underground frame) of the procedure which demolishes the existing building and constructs a new building by the building rebuilding method which concerns on the 3rd modification of this invention.

  In the present invention, as a method of rebuilding an existing building, earth and sand are backfilled in a part where the existing underground frame has been demolished, and a new pile for a new building is not constructed from the backfilled ground, but the existing underground frame is demolished. A new pile for a new building is constructed on the ground below the foundation, and an underground building for the new building is constructed on the new pile.

Specifically, as an embodiment, a new mountain retaining wall is constructed inside the existing underground outer wall, and the existing underground structure is used while decomposing the existing underground structure and constructing a mountain retaining structure during the construction of the new building. The first embodiment (Figs. 1 to 5) for constructing a pile for a new building from the dismantled ground, and the point that the upper end of the new mountain retaining wall is installed below the first basement floor level of the existing underground outer wall There is a second embodiment (FIG. 6) different from the first embodiment.
Moreover, as a modification, the point which constructs a new mountain retaining wall only in the existing underground outer wall surface in the longitudinal direction of the existing building is different from the above-described embodiments in the first modification (FIG. 7) and the existing underground outer wall. In the second modified example (FIGS. 8 to 10), in which the point of constructing a new retaining wall on the outside is different from the above-described embodiments, and in the excavation space, a retaining pile is provided in the vicinity of the inner side of the new retaining wall, There is a third modified example (FIG. 11) that is different from the above-described embodiments in that a new mountain retaining wall and a retaining pile are connected and supported by a beam.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted or simplified.
[First Embodiment]
FIG. 1 is a longitudinal sectional view of an existing building 1 to which the building rebuilding method according to the first embodiment of the present invention is applied.
The building rebuilding method of the present invention is to construct a new building after dismantling the existing building 1.
The existing building 1 includes an existing underground structure 2 constructed underground, and an existing ground structure 3 constructed on the existing underground structure 2.

The existing underground skeleton 2 is substantially rectangular in plan view (see FIG. 5), and has a reinforced concrete structure up to the second floor underground.
The existing underground frame 2 includes an existing pile 10, a footing 11 provided on the existing pile 10, a foundation beam 12 connecting the footings 11, a pressure plate 13 provided between the foundation beams 12, and a foundation beam. 12, existing columns 14 provided on the existing columns 12, existing beams 15 installed between the existing columns 14, existing floor slabs 16 provided between the existing beams 15 and between the basic beams 12, located on the outer periphery The existing underground outer wall 17 provided between the existing outer peripheral foundation beam 12a, the existing outer peripheral column 14a, and the existing outer peripheral beam 15a is provided.

Hereinafter, a procedure for dismantling the existing building 1 and constructing a new building will be described with reference to the flowchart of FIG.
In step S1, as shown in FIG. 3, the existing ground frame 3 is disassembled, and then a new retaining wall 20 is constructed along the existing underground outer wall 17 of the existing underground frame 2.
Specifically, the newly installed mountain retaining wall 20 is constructed inside the existing outer peripheral foundation beam 12 a, the existing outer peripheral column 14 a, the existing outer peripheral beam 15 a, and the existing underground outer wall 17.

  The retaining wall 20 includes a plurality of H-shaped steels that are driven in the horizontal direction at predetermined intervals along the existing underground outer wall 17 and a plate member that is bridged between adjacent H-shaped steels. It is a sheet pile. The mountain retaining wall 20 is constructed over the entire circumference of the existing underground skeleton 2 (see FIG. 5). Moreover, the upper end of this mountain retaining wall 20 is located in the ground surface. In this embodiment, the mountain retaining wall 20 is a main pile horizontal sheet pile, but the present invention is not limited to this, and the mountain retaining wall may be a steel sheet pile or an underground continuous wall.

In step S2, as shown in FIG. 4 and FIG. 5, the existing outer peripheral column 2 extends over the entire circumference of the existing underground skeleton 2 while laying the upper and lower two-stage support 30 between the newly installed mountain retaining walls 20. 14a, the existing outer peripheral beam 15a, and the existing underground outer wall 17 are left in place, and the existing underground frame 2 is disassembled to form an underground space 21.
Here, the support work 30 is attached to the surface of the newly installed retaining wall 20 and extends substantially horizontally, and a cutting beam 32 that is a square steel pipe laid between the uplifts 31. And a flame 33 provided between the erection 31 and the cut beam 32.

In step S 3, as shown in FIG. 4, an excavator 22 as a pile driving machine is disposed on the bottom surface of the underground space 21, and a pile hole 23 is formed in the ground below the underground space 21 using the excavator 22. Form.
Specifically, the excavator 22 is a low-head rotary excavator, and the pile hole 23 is formed by a rotary boring method or a top drive reverse method.

In the rotary boring method, a bit attached to the tip of a boring rod is rotated by a boring machine for excavation. At this time, a normal circulation method is adopted in which the excavated earth and sand are transported to the upper end of the pile hole by an ascending water flow and discharged by a sand pump.
On the other hand, the top drive reverse method, like the rotary boring method, drills by rotating the bit attached to the tip of the boring rod with a boring machine, but unlike the BH method, sucks the excavated earth and sand from the tip of the boring rod. A reverse circulation system is used.

In step S4, a new pile 24 is driven into the pile hole 23 as shown in FIG.
In step S <b> 5, a new underground structure of the new building is constructed on the new pile 24 while dismantling the support work 30.

According to this embodiment, there are the following effects.
(1) Since the excavator 22 is placed on the bottom surface of the underground space 21 formed by dismantling the existing underground frame 2 and the new pile 24 is driven on the bottom surface of the underground space 21, The process of refilling the underground space after dismantling the existing underground structure, the process of dismantling the retaining structure for demolition, the process of excavating to construct a new underground structure, and the process of constructing the retaining structure for the new underground structure Since it is not necessary, the building can be rebuilt in a short construction period while reducing construction costs.

  (2) As a pile driver, a low-head rotary excavator 22 was used. Since the low-head rotary excavator 22 excavates by rotating a boring rod attached to the boring machine, the height required for the pile driving operation is reduced, and as shown in FIG. However, the pile 24 can be constructed smoothly.

  (3) Since the newly installed mountain retaining wall 20 is constructed along the existing underground outer wall 17 of the existing underground frame 2, the axial rigidity of the mountain retaining wall 20 can be increased. In addition, since the cut beam 32 constructed between the new retaining walls 20 can be used both when the existing underground frame 2 is dismantled and when the new underground frame is constructed, the construction cost can be reduced and the building can be built in a short construction period. Can be rebuilt.

  (4) By using a square steel pipe for the cut beam 32, there is no difference between the strong axis and the weak axis in the cross section of the cut beam, and the buckling performance is improved. Therefore, even if the cutting beam 32 is elongated, a shelf pile that extends in the vertical direction and supports the cutting beam from below and a horizontal connection that connects the cutting beams are not required. Largely secured. In addition, since there is no shelf pile, there is no need for water-stopping work around the shelf pile as in the past, and there is no need to provide a useless hole for the shelf pile in the newly installed underground frame. Can be reduced.

[Second Embodiment]
In the present embodiment, the height position of the upper end of the newly installed mountain retaining wall 20A is different from that of the first embodiment.
That is, as shown in FIG. 6, the upper end of the newly installed mountain retaining wall 20A is located below the first basement floor level of the existing underground skeleton 2, and the total length of the newly installed mountain retaining wall 20A is the first embodiment. It is shorter than the newly installed mountain retaining wall 20.

According to this embodiment, in addition to the effects (1) to (4) described above, the following effects can be obtained.
(5) Since the newly installed retaining wall 20A is shorter than the retaining wall 20 in the first embodiment, the material cost for constructing the retaining wall 20A can be greatly reduced. Further, when the underground building of the new building is provided to a position deeper than the existing underground building 2 of the existing building 1, a new mountain retaining wall 20 </ b> A provided deeper than the existing underground outer wall 17 as in the present embodiment is provided on the existing underground outer wall 17. By providing it inside, the ground deeper than the existing underground skeleton can be excavated smoothly in a short construction period using the existing underground outer wall 17.

[First to third modifications]
It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.
For example, in each of the above-described embodiments, when dismantling the existing underground structure 2, the existing outer peripheral column 14a, the existing outer peripheral beam 15a, and the existing underground outer wall 17 are placed over the entire circumference of the existing underground structure 2, but this is not limitative. Absent. For example, as shown in FIG. 7, when dismantling the existing underground structure 2, the existing outer peripheral column 14 a, the existing outer peripheral beam 15 a, and the existing underground outer wall 17 may be placed only in the longitudinal direction of the existing underground structure 2. In this case, after constructing the new retaining wall 20 inside the existing outer peripheral column 14a, the existing outer peripheral beam 15a, and the existing underground outer wall 17, the existing underground structure 2 is dismantled while the retaining structure 30 is installed, Build a new underground structure. Here, only in the longitudinal direction of the existing underground frame 2, that is, only in the direction where the distance between the opposing retaining walls 20 is shorter, a new retaining wall 20 is constructed and a short span beam is constructed. Can be reconstructed at low cost by continuing from the dismantling of the existing underground building 2 until the construction of the new underground building.

  Moreover, in each above-mentioned embodiment, although the newly installed mountain retaining wall 20 was provided inside the existing outer periphery foundation beam 12a, the existing outer periphery pillar 14a, the existing outer periphery beam 15a, and the existing underground outer wall 17, it is not restricted to this, As shown in FIGS. 8 to 10, the newly installed retaining wall 20 </ b> B may be provided outside the existing outer peripheral foundation beam 12 a, the existing outer peripheral column 14 a, the existing outer peripheral beam 15 a, and the existing underground outer wall 17. In this case, in step S2 of the flow chart of the building rebuilding method shown in FIG. 2, the upper and lower two-stage support 30 is installed between the opposing new retaining walls 20, but at this time, as in the first embodiment The existing underground skeleton 2 is completely dismantled without forming a part of the existing underground skeleton 2 to form an underground space 21.

  Further, in each of the above-described embodiments, the cut beam 32 is installed between the opposing new mountain retaining walls 20. However, the present invention is not limited to this, and as shown in FIG. A plurality of H-beams are driven horizontally along the mountain retaining wall 20 at predetermined intervals to form a retaining pile 34, and a joining member 35 that connects these retaining piles 34 is provided, and the joining member 35 and the retaining wall 20 are connected to each other. You may connect with the cut beam 32. FIG. In this way, a large space can be secured in the central portion of the underground space 21, and the excavation work and the new pile 24 placement work can be performed smoothly.

DESCRIPTION OF SYMBOLS 1 ... Existing building 2 ... Existing underground frame 3 ... Existing ground frame 10 ... Existing pile 11 ... Footing 12 ... Foundation beam 12a ... Existing outer periphery foundation beam 13 ... Pressure-resistant version 14 ... Existing column 14a ... Existing outer column 15 ... Existing beam 15a ... Existing outer peripheral beam 16 ... Existing floor slab 17 ... Existing underground outer wall 20, 20A, 20B ... Mountain retaining wall 21 ... Underground space 22 ... Excavator (pile driver)
23 ... Pile hole 24 ... Newly built pile 30 ... Mountain retaining support 31 ... Raised 32 ... Cut beam 33 ... Fire-fired 34 ... Prep pile 35 ... Connecting member

Claims (3)

A method of rebuilding a building that builds a new underground structure after dismantling the existing underground structure,
Dismantling the existing underground structure to form an underground space;
Placing a pile driver on the bottom surface of the underground space, and placing a new pile on the ground below the underground space using the pile driver;
And a step of constructing a new underground structure on the new pile. The pile driver is a low-headed rotary excavator,
2. The step of placing the new pile includes forming a pile hole in the ground below the underground space using the rotary excavator, and then placing the new pile in the pile hole. The building rebuilding method described in 1. Before dismantling the existing underground structure, further comprising the step of constructing a new retaining wall along the existing underground outer wall of the existing underground structure,
In the step of dismantling the existing underground structure, a beam is installed between the new retaining walls facing each other,
The building rebuilding method according to claim 1 or 2, wherein in the step of constructing the new underground structure, the cut beam is dismantled.

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