JP6832761B2 - How to rebuild the building - Google Patents

Description

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

Conventionally, when rebuilding a building, it is often the case that an existing underground skeleton having an underground skeleton is dismantled and then a new underground skeleton having piles is constructed at the same location.
In this case, for example, the building is rebuilt according to the following procedure. First, the existing underground skeleton is dismantled while erection of a mountain retaining support for dismantling, and then the earth and sand are backfilled to the vicinity of the ground surface in the underground space formed by the dismantling of the existing underground skeleton. Next, a pile driver is placed on the backfilled soil to drive piles for a new building. Next, excavation will be carried out while erection of a pile support for the new underground skeleton. After that, while dismantling the pile support for the new underground skeleton, the new underground skeleton will be constructed from the lower layer to the upper layer.

For example, Patent Document 1 discloses a mountain retaining method used in a reverse construction method in which an underground skeleton is sequentially constructed from the ground surface side toward the lowest basement floor. Specifically, while constructing the outer peripheral underground skeleton in advance according to the root cutting depth, the underground skeleton is constructed by repeating the attachment of the cutting beam.

In addition, a structure with two steps of mountain retaining walls as shown below has been proposed as a retaining support.
Patent Document 2 describes an outer peripheral mountain retaining wall for excavating the outer peripheral position, an inner peripheral mountain retaining wall at the inner position of the outer peripheral mountain retaining wall, and a leg portion of the outer peripheral mountain retaining wall to the head of the inner peripheral mountain retaining wall. A pile support with a horizontal RC beam provided between them is shown.
Further, Patent Document 3 discloses a two-stage retaining wall in which an outer retaining wall and an upper end portion of the inner retaining wall constructed by separating a step excavation portion inside the outer retaining wall are connected by a connecting material.

However, when rebuilding a building, in the methods of Patent Documents 2 and 3, after completely backfilling the underground space formed by dismantling the existing underground skeleton, a pile for a new building is driven from the backfilled ground. After that, it was necessary to excavate the soil backfilled to the ground surface, which caused a problem that the construction period was prolonged and the construction cost was increased.

Japanese Unexamined Patent Publication No. 11-241353 JP-A-6-248650 JP-A-2007-162266

The present invention is intended for the dismantling and removal of an existing underground skeleton and the construction of a new underground skeleton accompanying the rebuilding of a building, and a new underground skeleton is constructed after the existing underground skeleton is dismantled in a short construction period and at low cost. The challenge is to provide a building rebuilding method that can be constructed.

The present inventors backfill the underground space that was removed by dismantling the existing underground skeleton to an intermediate height for the rebuilding work of the building, and the height position of the backfilled ground surface is the pile retaining support work ( By setting the backfilled ground surface position as the pile construction ground in a state where the retaining wall can stand on its own without the need for a girder), pile driving work can be performed efficiently and backfilling to the underground space. Focusing on the point that the amount of soil can be reduced, the building rebuilding method of the present invention was reached.

The building rebuilding method of the first invention is a building rebuilding method in which an existing underground skeleton (for example, the existing underground skeleton 2 described later) is dismantled and then a new underground skeleton (for example, the new underground skeleton 12 described later) is constructed. Therefore, a step of constructing a pile retaining wall (for example, a pile retaining wall 20 to 22 described later) (for example, step S1 described later) and an underground space (for example, an underground space 30 described later) by disassembling the existing underground skeleton A step of forming (for example, step S2 described later), a step of backfilling the underground space to an intermediate height of the underground space (for example, step S3 described later), and the backfilled ground surface (for example, the ground described later). A pile driver (for example, an excavator 33 described later) is arranged on the surface 32), and a new pile (for example, a new pile 11 described later) is driven into the ground below the underground space using the pile driver. It is characterized by including a step of setting (for example, step S4 described later) and a step of constructing a new underground skeleton on the new pile (for example, steps S5 and S6 described later).

According to the present invention, an underground space formed by dismantling an existing underground skeleton is backfilled to an intermediate height of the underground space, and a pile driver is arranged using the backfilled ground surface as a pile construction ground to form an underground space. A new pile was placed in the ground below. Therefore, it is not necessary to completely backfill the underground space after dismantling the existing underground skeleton as in the past, the amount of backfill soil used for the underground space can be reduced, and a new underground skeleton can be constructed in a short period of time and at low cost. it can.
In addition, when reclaimed crushed stone or reclaimed sand from the existing underground skeleton is used for backfilling the underground space, the cost of carrying out the dismantled glass can be reduced, and the amount of soil for backfilling can be reduced for backfilling. It is possible to reduce the cost of bringing in soil.

In the building rebuilding method of the second invention, in the step of backfilling the underground space, all the girders (for example, the girders 42 and 43 described later) erected between the retaining walls are dismantled. It is characterized in that backfilling is performed up to the height of the uppermost cutting beam (for example, the cutting beam 42 described later).

According to the present invention, since the underground space is backfilled to the height of the uppermost girder, no girder is installed on the backfilled ground surface, so that the pile driver can move and pile up smoothly. Since it can be carried out, the construction efficiency of the new underground skeleton will be high, the construction can be done in a short period of time, and the construction cost can be reduced. In addition, since the retaining wall is supported by the ground surface backfilled to the height of the uppermost girder, a self-supporting retaining wall can be realized.

In the building rebuilding method of the third invention, in the step of constructing the retaining wall, an outer retaining wall (for example, the outer retaining wall 20 described later) is constructed outside the existing underground skeleton, and the outer retaining wall is constructed. An inner retaining wall lower than the outer retaining wall (for example, the inner retaining wall 21 described later) is constructed inside, and the intermediate height of the backfilled underground space is substantially equal to the upper end level of the inner retaining wall. It is a feature.

According to the present invention, the ground is backfilled to the upper end level of the inner retaining wall, which is the intermediate height of the underground space, and the backfilled ground surface is used as the pile construction ground. Since no cutting beam is erected on the pile construction ground, the pile driver can be smoothly moved and the pile driving operation can be smoothly carried out on the pile construction ground. Therefore, the construction efficiency of the new underground skeleton is increased, the construction can be completed in a short period of time, and the construction cost can be reduced.
In addition, by setting the height of the backfilled ground surface to the upper end level of the inner retaining wall, it is possible to easily and surely manage the backfilling of the underground space.
In addition, by constructing a two-tiered retaining wall with an outer retaining wall and an inner retaining wall, the back earth pressure acting on the inner retaining wall is reduced. Therefore, the length and size of the core material constituting the inner retaining wall can be reduced, and the height of the inner retaining wall can be reduced.

According to the present invention, the existing underground skeleton is dismantled and the underground space formed is not completely backfilled, but is backfilled to the intermediate height of the underground space, and piles for a new building are driven from the backfilled ground surface. After that, by constructing the underground skeleton of the new building, it is possible to construct the new building after dismantling the existing underground skeleton in a short construction period and at low cost.

It is a flowchart of the construction procedure of a new building by the building reconstruction method which concerns on 1st Embodiment of this invention. It is explanatory drawing of the construction procedure of the new building (the first, the plan view which shows the construction state of the retaining wall). FIG. 2 is a sectional view taken along the line AA of FIG. FIG. 2 is a cross-sectional view taken along the line BB of FIG. It is explanatory drawing of the construction procedure of the new building (the second, the cross-sectional view which shows the backfilling situation of the underground space). It is explanatory drawing of the construction procedure of the new building (the third, the cross-sectional view which shows the driving situation of the new pile). It is explanatory drawing of the construction procedure of the new building (the fourth, the cross-sectional view which shows the excavation situation for the construction of a new underground skeleton). It is explanatory drawing (No. 5, sectional view of the new underground skeleton) of the construction procedure of the new building. It is explanatory drawing of the construction procedure of a new building by the building rebuilding method which concerns on 2nd Embodiment of this invention (the first, the plan view which shows the construction state of the retaining wall). 9 is a cross-sectional view taken along the line CC of FIG. It is explanatory drawing of the construction procedure of the new building (the second, the cross-sectional view which shows the dismantling state of the existing underground skeleton). It is explanatory drawing of the construction procedure of the new building (the third, the cross-sectional view which shows the backfilling situation of an underground space, and the driving situation of a new pile).

The present invention is a method for rebuilding a building, in which an existing underground skeleton is dismantled and removed, and the underground space is backfilled to an intermediate height, and the backfilled ground surface is used as a pile construction ground to drive a new pile. , Build a new underground skeleton on this new pile.
Specifically, as a building rebuilding method, after constructing a double beam retaining wall consisting of an inner retaining wall and an outer retaining wall on the outer periphery of the existing underground skeleton, the existing underground skeleton is dismantled to form an underground space. The first embodiment (FIGS. 1 to 8) in which the underground space is backfilled to the upper end level of the inner retaining wall and a new pile is placed using the backfilled ground surface as the pile construction ground, and the outer circumference of the existing underground skeleton. In addition, a single mountain retaining wall is constructed, and multiple upper and lower girders are erected between the retaining walls, and after dismantling the existing underground skeleton to form an underground space, the underground space is set to the height of the uppermost girder. There is a second embodiment (FIGS. 9 to 12) in which the backfilling ground is used as the pile construction ground.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the following embodiments, the same components will be designated by the same reference numerals, and the description thereof will be omitted or simplified.
[First Embodiment]
In the building rebuilding method according to the first embodiment of the present invention, after constructing a double retaining wall composed of an inner retaining wall 21 and an outer retaining wall 20 on the outer periphery of the existing building 1, the existing building 1 is dismantled. After that, a new building 10 is constructed (see FIGS. 2 to 4 and 8).

As shown in FIGS. 2 to 4, the existing building 1 includes an existing underground skeleton 2 constructed underground and an existing above-ground skeleton (not shown) constructed on the existing underground skeleton 2. The existing underground skeleton 2 has a reinforced concrete structure.

Hereinafter, the procedure for dismantling the existing building 1 to construct the new building 10 will be described with reference to the flowchart of FIG.
In step S1, as shown in FIGS. 2 to 4, after dismantling the existing ground skeleton, the pile drivers 20 and 21 are constructed from the ground surface 3 using a pile driver (not shown). That is, the outer retaining wall 20 is constructed, and the inner retaining wall 21 lower than the outer retaining wall 20 is constructed inside the outer retaining wall 20.

Specifically, the outer retaining wall 20 is a self-standing retaining wall having a steel horizontal sheet pile structure, and H-shaped steel is provided at predetermined intervals. Specifically, for example, the H-shaped steel is H-350 × 350, and the installation interval of the H-shaped steel is 1.5 m. Further, the distance from the ground surface 3 to the floor surface of this H-shaped steel (the backfilled ground surface 32 described later) is 3 m, and the penetration length is 9 m.

The inner retaining wall 21 is an SMW (Soil Mixing Wall) continuous wall provided along the outer wall surface of the existing underground skeleton 2. This SMW continuous wall is a wall body formed in the ground by mixing and stirring soil and cement slurry in the original position, and H-shaped steel is provided as a core material at predetermined intervals.
Specifically, for example, the H-shaped steel material used as the core material is H-588 × 300 × 12 × 20, the installation interval of the H-shaped steel is 0.6 m, and the rooting length is 12 m. Further, the diameter of the soil in which the core material is embedded is 0.85 m, the soil length is 15 m, and the actual soil length of the inner retaining wall 21 is 12 m. Further, as shown in FIGS. 3 and 4, the groundwater level 4 in the site is an intermediate height of the inner retaining wall 21 and is above the second floor surface 35 described later.

In step S2, as shown in FIG. 5, the existing underground skeleton 2 is disassembled to form the underground space 30. Specifically, the existing underground skeleton 2 is dismantled and excavated to the first floor surface 31 which is the bottom surface of the existing underground skeleton 2. In the state of excavating to the first floor surface 31, the outer retaining wall 20 and the inner retaining wall 21 are self-supporting.
In step S3, as shown in FIG. 5, the underground space 30 is backfilled to form the ground surface 32 from the first floor surface 31 to the upper end level of the inner retaining wall 21 which is the intermediate height of the underground space 30. To do. For this backfilling, recycled crushed stone or recycled sand obtained by dismantling the existing underground skeleton 2 is used.

In step S4, as shown in FIG. 6, an excavator 33 as a pile driver is arranged on the backfilled ground surface 32, and the excavator 33 is used to make a pile hole 34 in the ground below the underground space 30. And the new pile 11 is driven. Further, the support column 41 is driven in to support the cutting beam 40 described later. Specifically, the excavator 33 is a low-flying rotary excavator, and a pile hole 34 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 to excavate. In this rotary boring method, a normal circulation method is adopted in which the excavated earth and sand are carried to the upper end of the pile hole by an ascending water flow and discharged by a sand pump.
On the other hand, in the top drive reverse method, as in the rotary boring method, a bit attached to the tip of the boring rod is rotated by a boring machine to excavate. In this top drive reverse method, a reverse circulation method is adopted in which the excavated earth and sand are sucked up from the tip of the boring rod and discharged.

In step S5, as shown in FIG. 7, excavation is performed up to the second floor surface 35, which is the bottom surface of the new underground skeleton 12. At this time, while excavating between the inner retaining walls 21, a cutting beam 40 as a support is erected between the inner retaining walls 21 so as to be supported by the columns 41.

In step S6, as shown in FIG. 8, a new underground skeleton 12 of the new building 10 is constructed on the new pile 11.
The new underground skeleton 12 is provided on the footing 13 provided on the new pile 11, the foundation beam 14 connecting the footings 13 to each other, the pressure-resistant plate 15 provided between the foundation beams 14, and the foundation beam 14. The columns 16 are provided, beams 17 erected between the columns 16, floor slabs 18 provided between the beams 17 and between the foundation beams 14, and an underground outer wall 19 located on the outer periphery thereof.
After that, a new above-ground skeleton of the new building 10 is constructed.

According to this embodiment, there are the following effects.
(1) The underground space 30 formed by dismantling the existing underground skeleton 2 is backfilled to an intermediate height of the underground space 30, and the excavator 33 is placed underground using the backfilled ground surface 32 as the pile construction ground. A new pile 11 was placed in the ground below the space 30. Therefore, it is not necessary to completely backfill the underground space after dismantling the existing underground skeleton as in the conventional case, the amount of backfill soil used for the underground space 30 can be reduced, and the new underground skeleton 12 can be constructed in a short period of time and at low cost. Can be built.

(2) Since recycled crushed stone and recycled sand obtained by dismantling the existing underground skeleton 2 were used for backfilling the underground space 30, the cost of carrying out the dismantled glass can be reduced, and the amount of soil for backfilling can be reduced to backfill. It is possible to reduce the cost of bringing in soil for use.

(3) It was backfilled to the upper end level of the inner retaining wall 21, which is the intermediate height of the underground space 30, and the backfilled ground surface 32 was used as the pile construction ground. Since the cutting beam 40 is not erected on the pile construction ground, the excavator 33 can be smoothly moved and the pile driving operation can be performed on the pile construction ground. Therefore, the construction efficiency of the new underground skeleton 12 is increased, the construction can be carried out in a short construction period, and the construction cost can be reduced.

(4) By setting the height of the backfilled ground surface 32 to the upper end level of the inner retaining wall 21, the backfilling management of the underground space 30 can be easily and surely performed.
(5) By constructing the two-stage retaining wall by the outer retaining wall 20 and the inner retaining wall 21, the back earth pressure acting on the inner retaining wall 21 is reduced. Therefore, the length and size of the core material constituting the inner retaining wall 21 can be reduced, and the height of the inner retaining wall 21 can be reduced.

(6) Since the groundwater level 4 in the construction site is above the second floor surface 35 which is the bottom surface of the new underground skeleton 12, the outer retaining wall 20 is made of steel horizontal sheet pile structure as a two-stage retaining wall. The inner retaining wall 21 is a continuous SMW wall. As a result, groundwater can be stopped at the outer wall surface of the inner retaining wall 21 and a two-stage retaining wall can be constructed at low cost.

[Second Embodiment]
The building rebuilding method of the present embodiment is to construct a single retaining wall 22 on the outer periphery of the existing building 1, then dismantle the existing building 1, and then construct a new building 10.
The present embodiment is different from the first embodiment in that the retaining wall 22 is constructed in a single layer and the height position of the ground surface 32 that backfills the underground space 30 is at the level of the upper beam 42. ..

Hereinafter, a procedure for dismantling the existing building 1 to construct the new building 10 will be described with reference to the flowchart of FIG. In this embodiment, only steps S1 to S4 are different from those in the first embodiment. Therefore, the description of steps S5 and S6 will be omitted.

In step S1, as shown in FIGS. 9 and 10, after dismantling the existing ground skeleton, a pile driver (not shown) is used to construct the retaining wall 22 from the ground surface 3. The retaining wall 22 is a single retaining wall provided on the outer periphery of the existing building 1. In the present embodiment, since the groundwater level 4 is higher than the floor surface 36, the retaining wall 22 is a SMW continuous wall having excellent water stopping property. Not limited to this, the retaining wall 22 may be constructed of an RC continuous wall, an RC colonnade wall, or the like. When the groundwater level is lower than the floor surface 36, the retaining wall may be constructed of a main pile steel sheet pile wall or a steel sheet pile wall.

In step S2, as shown in FIG. 11, the existing underground skeleton 2 is dismantled to form the underground space 30 while erection of the upper and lower two-stage cutting beams 42 and 43 between the retaining walls 22. Specifically, the existing underground skeleton 2 is dismantled and excavated to the floor surface 36 which is the bottom surface of the existing underground skeleton 2.

In step S3, as shown in FIG. 12, while removing the upper and lower two-stage girders 42 and 43 erected in the underground space 30, the underground space 30 is backfilled to the level of the uppermost girder 42 to refill the ground. The surface 32 is formed. For this backfilling, regenerated crushed stone or regenerated sand obtained by dismantling the existing underground skeleton 2 is used. Further, in the state of backfilling up to the ground surface 32, the retaining wall 22 is self-supporting.

In step S4, as shown in FIG. 12, an excavator 33 as a pile driver is arranged on the backfilled ground surface 32, and the excavator 33 is used to make a pile hole 34 in the ground below the underground space 30. And the new pile 11 is driven.

According to this embodiment, in addition to the above-mentioned effects (1) and (2), there are the following effects.
(7) The underground space 30 was backfilled to the height of the uppermost girder 42, and the backfilled ground surface 32 was used as the pile construction ground. Since the cutting beam 42 is not erected on the pile construction ground, the excavator 33 can be smoothly moved and the pile driving operation can be performed on the pile construction ground. Therefore, the construction efficiency of the new underground skeleton 12 is increased, the construction can be carried out in a short construction period, and the construction cost can be reduced.

(8) Since the retaining wall 22 is supported by the ground surface 32 backfilled to the height of the uppermost cutting beam 42, a self-supporting retaining wall can be realized.
(9) By setting the height of the backfilled ground surface 32 to the height of the uppermost girder 42, the backfilling management of the underground space 30 can be easily and surely performed.

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.
For example, in the first embodiment, a two-stage retaining wall is constructed by the outer retaining wall 20 and the inner retaining wall 21, but the present invention is not limited to this, and instead of the outer retaining wall 20, a slope-cut open-cut method having a slope is used. You may excavate.

1 ... Existing building 2 ... Existing underground skeleton 3 ... Ground surface 4 ... Ground water level 10 ... New building 11 ... New pile 12 ... New underground skeleton 13 ... Footing 14 ... Foundation beam 15 ... Pressure-resistant version 16 ... Pillar 17 ... Beam 18 ... Floor Slab 19 ... Underground outer wall 20 ... Outer mountain retaining wall 21 ... Inner retaining wall 22 ... Mountain retaining wall 30 ... Underground space 31 ... First floor surface 32 ... Backfilled ground surface 33 ... Excavator (pile driving machine) 34 ... Pile hole 35 ... 2nd floor surface 36 ... Floor surface 40 ... Cutting beam 41 ... Column 42 ... Upper cutting beam 43 ... Lower cutting beam

Claims (2)

It is a building rebuilding method to build a new underground skeleton after dismantling the existing underground skeleton.
The process of constructing the retaining wall and
The process of dismantling the existing underground skeleton to form an underground space,
The process of backfilling the underground space to the intermediate height of the underground space,
A process of arranging a pile driver on the backfilled ground surface and using the pile driver to drive a new pile into the ground below the underground space.
With the process of constructing a new underground skeleton on the new pile ,
In the step of backfilling the underground space, a building rebuilding method is characterized in that all the girders erected between the retaining walls are dismantled and backfilled to the height of the uppermost girder. In the step of constructing the retaining wall, an outer retaining wall is constructed on the outside of the existing underground skeleton, and an inner retaining wall lower than the outer retaining wall is constructed on the inside of the outer retaining wall.
The backfill mid-height of the underground space was the building rebuilding method according to claim 1, characterized in that approximately equal to the upper level of the inner earth retaining wall.

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