JP5885603B2 - Construction method of Yamadome wall - Google Patents

Description

  The present invention relates to a method for constructing a mountain retaining wall. Specifically, the present invention relates to a method for constructing a simple mountain retaining wall in a narrow work space.

  Conventionally, there are cases where a part of the basement of an existing building is left to build a new building, or a building is added to the basement of an existing building. In this case, for example, a part of the underground building of the existing building is used as a mountain retaining wall, and a new mountain retaining wall is constructed continuously from the underground building (see Patent Document 1).

That is, in Patent Document 1, a mountain retaining wall such as a soil cement continuous wall is created in the lower part of the existing frame, and a cylindrical ground improvement is made in the gap part of the mountain retaining wall where the mountain retaining wall cannot be created by beams of the existing building. The body is constructed, and this ground improvement body is also used as a part of the mountain wall.
The ground improvement body of the gap part of this mountain retaining wall is constructed as follows. First, a small excavator is installed in the basement of an existing building. This excavator drills a hole by pushing it while rotating the rod. After driving the excavator and drilling holes with the rod, while lifting the rod, the cement milk is discharged from the tip of the rod, the cement milk and the soil are stirred, and a ground improvement body is constructed.

  For the part that interferes with the beam of the existing building, drill the hole for ground improvement in the beam of the existing building and use this hole, or improve the ground of the area where the mountain retaining wall is not installed from both sides of the beam. Do. Furthermore, if necessary, a ground solidifying agent using a chemical solution is injected into the gap between the ground improvement body and the mountain retaining wall to complete the required quality of the mountain retaining wall such as water stoppage.

  In the method of Patent Document 1, the groundwater level is lowered by a deep well or the like in preparation for building a mountain retaining wall such as a soil cement continuous wall, and all floors and pressure plates of the existing frame of the mountain retaining wall planned part are dismantled. Therefore, it is necessary to place the fluidized soil to a position higher than the normal water level of groundwater, which is a large-scale construction.

JP 2010-281038 A

  However, if the difference between the building depth of the new building and the existing building is not so large, and the depth of additional drilling is about 1m or less, the groundwater level is not so high and the ground condition is not so bad, There is a case that it is not necessary to have a mountain wall with high rigidity and high water stopping performance like a soil cement continuous wall.

  An object of the present invention is to provide a method for constructing a new simple mountain retaining wall continuously to the underground structure when, for example, a part of the underground structure of an existing building is used as the mountain retaining wall.

The method for constructing a mountain retaining wall according to claim 1 is a method for constructing a mountain retaining wall for dismantling an existing building having an underground floor and constructing a new building having an underground floor deeper than the underground floor. The mountain retaining wall is constructed continuously below the outer wall portion of the underground building of the existing building and continuously to the outer wall portion, and a drilling device (for example, a drilling device 10 described later) is formed from the bottom surface of the existing building. ) To drill holes in the ground (for example, step S2 to be described later), and to construct ground improvement bodies (for example, ground improvement bodies 22 and 27 to be described later) while driving the excavator and pulling out the rods. Step (for example, step S3 to be described later) and a steel pipe (for example, a gas pipe 50 to be described later) having a diameter smaller than that of the rod and connectable to each other are prepared, and the excavator is driven to add the steel pipe. Extend Inserting the steel pipe to the ground improvement (e.g., step S4 described later), characterized in that it comprises a a.

According to this invention, what connected the steel pipe by the screw joint is inserted in a ground improvement body, and it utilizes as a parent pile or a core material. For example, a ground improvement body is constructed by injecting a chemical solution having a water-stopping property with a rod, and a steel wall inserted by the ground improvement body is used as a parent pile to construct a mountain retaining wall by a parent pile lateral sheet pile method. Alternatively, a cement-like ground improvement body is constructed by discharging cement milk from the rod and stirring with the soil, and a mountain retaining wall made of a soil cement continuous wall is constructed with the steel pipe inserted into the ground improvement body as a core material.
Therefore, even in a narrow work space such as an underground structure of an existing building, it is only necessary to handle one steel pipe of a predetermined length at a time, so that the steel pipe is securely inserted into the ground improvement body and connected to the underground structure. Can build a mountain wall.
In addition, even if steel pipes are used instead of I-shaped steel and H-shaped steel, if the required self-supporting height of the retaining wall is not so high, a sufficient retaining rigidity can be secured and a simplified retaining wall can be provided. Since it can be constructed, it is practical.
In addition, a certain degree of water-stopping can be expected by injection of a chemical solution having water-stopping properties and a soil cement continuous wall.

  The mountain retaining wall construction method according to claim 2 is characterized in that the steel pipe is a carbon steel pipe for piping (for example, a gas pipe 50 described later).

  Here, as a carbon steel pipe for piping, the carbon steel pipe for piping prescribed | regulated to JISG3452 is mentioned, for example.

According to this invention, for example, a so-called gas pipe is used as a steel pipe among carbon steel pipes for piping. Since the gas pipe is a commercial product, the construction cost of the retaining wall can be greatly reduced.
Moreover, if it is a gas pipe, since gas pipes can be easily connected with a threaded joint with a wrench and there are also abundant sizes, since a thing with a smaller diameter than a rod can be obtained easily, workability | operativity can be improved.

  According to this invention, what connected the steel pipe by the screw joint is inserted in a ground improvement body, and it utilizes as a parent pile or a core material. For example, a ground improvement body is constructed by injecting a chemical solution having a water-stopping property with a rod, and a steel wall inserted by the ground improvement body is used as a parent pile to construct a mountain retaining wall by a parent pile lateral sheet pile method. Alternatively, a cement-like ground improvement body is constructed by discharging cement milk from the rod and stirring with the soil, and a mountain retaining wall made of a soil cement continuous wall is constructed with the steel pipe inserted into the ground improvement body as a core material. Therefore, even in a narrow work space such as an underground structure of an existing building, it is only necessary to handle one steel pipe of a predetermined length at a time, so that the steel pipe is securely inserted into the ground improvement body and connected to the underground structure. Can build a mountain wall. In addition, even if steel pipes are used instead of I-shaped steel and H-shaped steel, if the required self-supporting height of the retaining wall is not so high, a sufficient retaining rigidity can be secured and a simplified retaining wall can be provided. Since it can be constructed, it is practical. In addition, a certain amount of water-stopping can be expected by chemical solution injection and soil cement continuous wall.

It is sectional drawing (the 1) for demonstrating the construction method of the new building to which the construction method of the mountain wall which concerns on 1st Embodiment of this invention was applied. It is sectional drawing (the 2) for demonstrating the construction method of the new building which concerns on the said embodiment. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is a flowchart of the construction method of the mountain retaining wall which concerns on the said embodiment. It is a layout of the excavator of the construction method of the new building which concerns on the said embodiment. It is a disassembled perspective view of the outer tube and inner tube of the rod of the excavator according to the embodiment. It is a disassembled perspective view of the steel pipe inserted by the excavation apparatus which concerns on the said embodiment. It is sectional drawing of the mountain retaining wall constructed | assembled with the construction method of the mountain retaining wall which concerns on 2nd Embodiment of this invention.

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]
1 and 2 are cross-sectional views for explaining a construction method for a new building 2 to which a mountain wall construction method according to the first embodiment of the present invention is applied.
That is, the construction method of the new building 2 is a method of dismantling the existing building 1 shown in FIG. 1 and newly constructing a new building 2 indicated by a broken line in FIG.

  Compared with the existing building 1, the new building 2 has a smaller floor area, but the depth of the basement is deeper. Therefore, a mountain retaining wall 20 is constructed continuously from the outer wall portion 4 below the outer wall portion 4 of the underground building 3 of the existing building 1, and the new building 2 is connected to the mountain retaining wall 20 and a part of the outer wall portion 4. Use as a mountain wall for construction. In this embodiment, the mountain retaining wall 20 is constructed by the parent pile horizontal sheet pile method.

The construction method of the new building 2 is specifically as follows.
First, as shown in FIG. 1, the existing building 1 has an underground skeleton 3 up to the second floor. Therefore, a small excavation device 10 is installed on the floor surface 5 at the second basement level of the underground frame 3, and the parent pile body extending downward from the floor surface 5 as shown in FIG. 3 using this excavation device 10. 21 is constructed continuously in the horizontal direction.

3 is a cross-sectional view taken along the line AA in FIG.
The parent pile body 21 includes a substantially cylindrical ground improvement body 22 constructed by improving the ground by injecting a chemical solution having a water-stopping property, and a parent pile 23 inserted in the approximate center of the ground improvement body 22; Consists of.
Adjacent ground improvement bodies 22 partially overlap each other, whereby the ground improvement bodies 22 are continuous in the horizontal direction.

  Next, as shown in FIG. 2, the outer wall portion 4 of the underground building 3 is left to be dismantled, and the mountain retaining wall 20 is used as a mountain retaining wall in addition to the outer wall portion 4 to the floor surface of the new building 2. Excavate and build a new building 2. Here, at the time of excavation, as shown in FIG. 4, the main pile body 21 is also excavated to expose the main pile 23, and a cross pile 24 is fitted to the back side of the main pile 23 to construct the mountain retaining wall 20. . At this time, since the ground improvement body 22 is the ground improvement body constructed | assembled by chemical | medical solution injection | pouring, a certain amount of water stop can be anticipated, and also excavation becomes easy.

Hereinafter, the procedure for continuously constructing the parent pile body 21 will be described with reference to the flowchart of FIG.
First, in step S1, as shown in FIG. 6, the small excavator 10 is set at the initial position.
The excavator 10 pushes and pulls down the cylindrical rod 11 while rotating it.
The rod 11 is a double tube, and includes a cylindrical outer tube 30 and an inner tube 40 accommodated in the outer tube 30.

FIG. 7A is an exploded perspective view of the outer tube 30.
The outer tube 30 includes a cylindrical outer tube main body 33 connected by a plurality of joint members 32, and a tip bit 34 attached to the tip of the outer tube main body 33.
FIG. 7B is an exploded perspective view of the inner tube 40.
The inner tube 40 has a cylindrical inner tube main body 43 connected by a plurality of joint members 42, and a tip bit 44 attached to the tip of the inner tube main body 43.

  In step S2, the excavator 10 is driven to drill holes in the ground. At this time, the rod 11 is extended by using the joint members 32 and 42 so that the rod 11 is gradually extended so that the tip of the rod 11 reaches a predetermined depth.

  In step S3, the excavator 10 is driven, and the rod 11 is gradually pulled out from the drilled hole while injecting a water glass-based two-liquid mixed type chemical from the tip of the rod 11 as a water-stopping chemical. The ground improvement body 22 is constructed. At this time, the length of the rod 11 is gradually shortened by removing it sequentially from the upper end side of the rod 11.

In step S <b> 4, the excavator 10 is driven, and the gas pipe 50 as a steel pipe is inserted into the ground improvement body 22 through the drilled hole to form the parent pile 23.
FIG. 8 is an exploded perspective view of the gas pipe 50.
The gas pipe 50 is a carbon steel pipe for piping as defined in JIS G 3452. The gas pipe 50 is slightly smaller in diameter than the rod 11 and can be connected to each other by a joint member 51 using a screw.

  Therefore, by newly adding the gas pipe 50 to the upper end of the already inserted gas pipe 50 by using the joint member 51 with a screw, the parent pile 23 is gradually extended, and the lower end of the parent pile 23 is drilled. Try to reach the depth of the hole.

In step S5, it is determined whether or not all the parent pile bodies 21 are completed. If this determination is Yes, the process ends. If it is No, the process proceeds to step S6.
In step S6, the excavator 10 is set to the next position, and the process returns to step S2.

According to this embodiment, there are the following effects.
(1) The gas pipe 50 connected was inserted into the ground improvement body 22 and used as the parent pile 23. Therefore, even in a narrow work space like the second floor of the existing building 1, it is only necessary to handle one steel pipe of a predetermined length at a time, so that the gas pipe 50 is securely inserted into the ground improvement body 22. The mountain retaining wall 20 can be constructed continuously to the outer wall portion 4 of the underground frame 3.
For example, as shown in FIG. 6, the worker A holds the gas pipe 50 with both hands on the second basement floor, but by using the gas pipe 50 that is sufficiently shorter than the floor height, the work space is narrow. However, it can be handled sufficiently.
In addition, even if the gas pipe 50 is used instead of the I-shaped steel or the H-shaped steel, if the required self-standing height of the retaining wall is not so high, the retaining wall having a simple structure with sufficient sectional rigidity is ensured. Since the wall 20 can be constructed, it is practical.
Moreover, since the ground improvement body 22 was constructed | assembled by injection | pouring of the chemical | medical solution with a water stop, a certain amount of water stop is also expectable.

(2) The parent pile 23 was formed using a galvanized steel pipe, so-called gas pipe 50. Since the gas pipe is a commercial product, the construction cost of the mountain retaining wall 20 can be greatly reduced.
Moreover, if it is a gas pipe, since gas pipes can be easily connected with a threaded joint with a wrench, and there are also abundant sizes, since a thing with a smaller diameter than the rod 11 can be obtained easily, workability can be improved. .

[Second Embodiment]
FIG. 9 is a cross-sectional view of a mountain retaining wall 20A to which the mountain retaining wall construction method according to the second embodiment of the present invention is applied.
The present embodiment is different from the first embodiment in that the mountain retaining wall 20A is constructed by a soil cement continuous wall.
That is, the excavation device 10 is installed on the floor surface 5 of the underground second floor level of the underground frame 3, and the element 26 extending downward from the floor surface 5 is continuously constructed in the horizontal direction using the excavation device 10. It is set as the mountain retaining wall 20A of a soil cement continuous wall.

The element 26 includes a substantially cylindrical ground improvement body 27 constructed by improving the ground by stirring cement milk and soil, and a core material 28 inserted at the approximate center of the columnar ground improvement body 27, Consists of.
Adjacent ground improvement bodies 27 partially overlap each other, whereby the ground improvement bodies 27 are continuous in the horizontal direction.

Further, the procedure for constructing the mountain retaining wall 20A of the present embodiment is different from the first embodiment in steps S3 and S4 of the flowchart of FIG.
That is, in step S3, the excavator 10 is driven to discharge the cement milk from the tip of the rod 11 and stir the cement milk and the soil, and then gradually pull out and remove the rod 11 from the drilled hole. An improved body 27 is constructed.
In step S4, the excavator 10 is driven to insert the gas pipe 50 as a steel pipe into the ground improvement body 27 through the drilled hole, and the gas pipe 50 is used as the core material 28 of the ground improvement body 27. .

According to the present embodiment, there are the same effects as the above (1) and (2).
Moreover, since the space | interval of the ground improvement body 27 becomes narrow compared with 1st Embodiment, the number of the ground improvement bodies 27 will increase, However, a side sheet pile is unnecessary and can reduce excavation work.

  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.

DESCRIPTION OF SYMBOLS 1 ... Existing building 2 ... New building 3 ... Underground frame 4 ... Outer wall part 5 ... Floor surface 10 ... Excavator 11 ... Rod 20, 20A ... Yamato wall 21 ... Parent pile body 22 ... Ground improvement body by chemical injection 23 ... Parent Pile 24 ... Cross sheet pile 26 ... Element 27 ... Soil cement continuous wall ground improvement body 28 ... Core material 30 ... Outer pipe 32 ... Joint member 33 ... Outer pipe body 34 ... Tip bit 40 ... Inner pipe 42 ... Joint member 43 ... Inside Pipe body 44 ... Tip bit 50 ... Gas pipe (carbon steel pipe for piping)
51. Joint member

Claims (2)

A method for constructing a mountain wall for dismantling an existing building having a basement floor and constructing a new building having a basement floor deeper than the basement floor,
The mountain retaining wall is constructed continuously under and on the outer wall portion of the underground structure of the existing building,
Drilling a drilling device from the bottom floor of the existing building to drill holes in the ground;
Constructing a ground improvement body while driving the excavator and pulling out the rod;
Providing a steel pipe having a diameter smaller than that of the rod and connectable to each other by a threaded joint, and driving the excavator to insert the steel pipe into the ground improvement body while extending and extending the steel pipe. A method of constructing a mountain wall characterized by   The said steel pipe is a carbon steel pipe for piping, The construction method of the mountain retaining wall of Claim 1 characterized by the above-mentioned.

Images