JPH04203028A - Reverse driving method for underground building - Google Patents

Abstract

PURPOSE:To shorten a term of works and to reduce the cost by a method wherein an existing pile to which a concrete pile with an outer shell steel pipe is connected is used as a high strength pile, the existing pile is driven in a ground, and a structure main column is erected on the existing pile. CONSTITUTION:Ordinary excavation is carried out down to an underground first floor, a hole 2 for placing a pile is excavated in a given position from a ground 1, and stabilizing liquid (a) is poured in the hole 2. A concrete pile with an outer shell steel pipe which is covered with a steel pipe is used in the hole 2 and as a high strength pile 3 and an existing pile 4 to which a steel pipe pile 5 is connected is driven therein. A pipe is inserted in the pile 5, the portion in the vicinity of a bottom part of the pile 5 is filled with a foundation solidifying liquid (b), and a structure main column 6 is driven in a pile 5 part. Level precision is ensured by fixed installation of the pile 6, and simultaneously with ground construction at the upper part of the column 6, construction is carried out from the upper layer toward the lower layer of an underground floor. This method shortens the term of works and reduce the cost.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a reverse driving method for underground construction, and in particular to a ready-made pile constructed by connecting a high-strength pile with a concrete shaft with an outer shell steel pipe or a steel pipe pile. Regarding the reverse pouring method used for underground construction.

(Prior art) Generally, when constructing a building with a basement, the roots of the entire building are cut down to the bottom of the foundation in advance, and the foundation concrete for the lowest basement floor is poured. The building is being constructed from the bottom to the top, with concrete being poured from the bottom to the top, starting with the first floor, second floor, first floor, and first floor above ground.

However, in such a forward pouring method, the construction period required to construct the above-ground portion after the underground portion is constructed becomes long, so in recent years, the reverse pouring method has been increasingly used. In the reverse driving method, foundation piles are driven in advance at predetermined positions on the ground where building columns are to be erected, and at the same time ground construction is carried out on the top of the structural pillars erected on top of the foundation piles. This method involves cutting down roots and pouring concrete from the upper basement level to the lower level. For example, in the case of an underground part or pure reinforced concrete structure (RC structure) where concrete is poured, or an above ground part or steel reinforced concrete structure (SRC structure), a vertical hole is drilled from the ground surface to the position where the column will be placed, and the foundation pile is poured by concrete. make. Foundation piles constructed in this way are usually called cast-in-place piles. On top of these foundation piles, we will erect temporary pillars, or structure pillars, and then erect the upper steel frame on top of these pillars to construct the above-ground section. At the same time, we will cut down the roots of the underground section, and Construction is carried out by gradually pouring concrete into the underground section from the beginning to the lower floors.

According to such a reverse construction method, the above-ground and underground sections can be constructed at the same time, thereby effectively shortening the construction period.

(Problems to be Solved by the Invention) In the conventional reverse driving method, a cast-in-place pile is used as a foundation pile, and a 4RM column is erected on this cast-in-place pile. Even in the case of direct foundations, cast-in-place piles were driven as temporary construction.

However, since the formation of cast-in-place piles itself takes a certain amount of time and costs I, there is room for further shortening the construction time and lowering costs.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a reverse pouring method for underground construction that can shorten the construction period and reduce the cost of construction of layers compared to the conventional method.

(Means for Solving the Problems) When constructing a building having a basement underground, the present invention includes driving foundation piles in advance at predetermined positions on the ground where pillars of the building are to be erected,
In the reverse pouring method for underground construction, which involves cutting the roots and pouring concrete from the upper basement level to the lower level at the same time as above-ground construction of the upper part of the structural pillars erected on the foundation piles, high-strength The present invention is characterized in that a ready-made pile in which a steel pipe pile is connected to the pile is used, and after the ready-made pile is driven into the ground, a structural pillar is erected on top of the ready-made pile.

Mat: The present invention provides for underground construction of a building having a basement,
Foundation piles are driven in advance at predetermined positions on the ground where the pillars of the building are to be erected, and at the same time as ground construction is carried out on the upper part of the structural pillars erected on top of the foundation piles, root cutting and work is carried out from the upper basement level to the lower level. In the reverse driving method for underground construction in which concrete is placed, ready-made piles consisting of high-strength piles and concrete piles with outer shell steel pipes are used as the foundation piles, and after the ready-made piles are driven into the ground, It is characterized by the structure pillars being built on top of ready-made piles.

Furthermore, the structure pillar is fixedly installed by injecting a foot hardening fixing liquid into the ready-made pile.

(Function) According to the construction method of the present invention described above, prefabricated piles in which concrete piles with outer shell steel pipes or steel pipe piles are connected to high-strength piles are used as foundation piles, so they can be used in locations that require relatively large-scale underground excavation. Compared to the case of using driven piles, the construction period and cost of the -layer can be shortened and costs reduced.

As the high-strength shafts that make up the ready-made piles, various piles can be used as long as they have sufficient strength, such as PC piles, PHC piles, and concrete piles with outer shell steel pipes.
As for its formation method, centrifugal force molding or various molding methods can be employed.

Furthermore, since the structural pillars built on top of ready-made piles are fixed by injecting the foundation hardening fixative into the ready-made piles, the positioning and holding of the structural pillars is also reliable.

(Example) Embodiments of the present invention will be described below with reference to FIG.

In this example, basically, when constructing a building with a basement underground, foundation piles are driven in advance at predetermined positions on the ground where the pillars of the building are to be erected, and the upper part of the structural pillars erected on top of the foundation piles is used. In the reverse pouring method for underground construction, which involves cutting the roots and pouring concrete from the upper basement level to the lower level at the same time as above-ground construction,
A ready-made pile 4 in which a steel pipe pile 5 is connected to a light-strength pile 3 is used as a foundation pile, and after the ready-made pile 4 is driven into the ground, a horizontal straight column 6 is erected on top of the ready-made pile 4. In addition, ready-made piles 4
The structure pillar 6 is fixedly installed by injecting a foot hardening fixing solution into the hole.

In the case of a pile foundation for a building, ready-made piles 4 are often designed in consideration of the condition of the strata, workability, cost, construction period, etc. Moreover, recently, the diameter of ready-made pile 4 has also increased to Φ800.
Ready-made piles 4 such as ~Φ1000 may be used.

Therefore, it is fully possible to use the ready-made piles 4 as they are and use the reverse driving method.

In addition, in this example, the floor above the basement level, the SRC structure, the second basement floor
The construction of a building with an RC structure below the floors is explained.

First, perform regular root cutting down to the first basement floor. Then, holes 2 for installing piles are drilled from the ground surface at predetermined positions where building supports are to be erected using various flaying methods.

In addition, to prevent hole 2 from collapsing, add a stabilizer such as bentonite a.
Inject into hole 2.

A ready-made pile 4 is driven into this hole 2 as a foundation pile, and necessary centering is performed. In this embodiment, this ready-made pile 4 is a high-strength pile 3
A concrete column with a steel pipe outer shell coated with a steel pipe is used as a concrete pillar, and a steel pipe pile 5 is connected to this. Other high-strength piles with sufficient strength are PC piles.

Various types of piles such as PHC piles can be used, and their formation methods can include centrifugal force molding and various other molding methods.

Note that 7 is a reinforcing plate.

After the ready-made pile 4 configured as described above is driven into the ground, the structural pillar 6 is erected on top of the ready-made pile 4. Prior to this, a pipe or hose, etc. is inserted into the steel pipe pile 5 section, and a foot hardening fixing solution is filled near the bottom of the steel pipe pile 5. I will try to build it up.

In this way, by injecting the foot hardening fixing solution into the steel pipe pile 5 and fixing the structure pillar 6, the level accuracy is maintained, and the steel pipe pile 5, and by extension the ready-made pile 4, and the structure pillar 6 are fixedly installed. Integrate with pillar 6.

After this, at the same time as above-ground construction on the upper part of the structure pillar 6, root cutting and construction from the upper basement floor to the lower floor are performed.

According to the above-mentioned embodiment, the bearing capacity required by the reverse driving method is 200 mm, which is possible with the diameter of Φ800 to Φ1000 of the ready-made pile 4.
It was confirmed that if the weight is 300 tons, there is no need to use conventional cast-in-place piles, and it can be done at a relatively low cost.

Furthermore, according to this embodiment, ready-made piles 4, which are high-strength piles 3 and steel pipe piles 5 connected, are used as foundation piles, so compared to the case where cast-in-place piles are used, which requires relatively large-scale underground excavation, etc. Furthermore, it is possible to shorten the construction period and reduce the cost of the layer.

Moreover, since the structural pillars 6 built on top of the ready-made piles 4 are fixedly installed by injecting the hardening fixing liquid into the steel pipe piles 5, the positioning and holding of the structural pillars 6 is also reliable.

In addition, in the above-described embodiment, a high-strength pile 3 connected to a steel pipe pile 5 was used as the ready-made pile 4, but the present invention is not limited to this. Of course, various ready-made piles can be used, and similar effects can be achieved in such cases as well.

(Effects of the Invention) As described above, according to the present invention, a ready-made pile in which a high-strength pile is connected to a concrete pile with an outer shell steel pipe or a steel pipe pile is used as a foundation pile, which requires relatively large-scale underground excavation. Compared to the case of using cast-in-place piles, excellent effects such as shortening the construction period and cost reduction of the layer are achieved.

In addition, since the horizontal main pillars built on top of ready-made piles are fixedly installed by injecting the root hardening fixative into the ready-made piles, the positioning and retention of the main pillars is also reliable.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention. 3... High strength pile 4... Ready-made pile 5...
・Steel pipe pile 6... Structure pillar b... Root hardening fixing solution

Claims (3)

[Claims] (1) When constructing a building with a basement underground, foundation piles are driven in advance at predetermined positions on the ground where the pillars of the building are to be erected, and above-ground construction is carried out above the structural pillars erected on top of the foundation piles. At the same time, in the reverse driving method for underground construction, which involves cutting down roots and pouring concrete from the upper level of the basement to the lower level, ready-made piles consisting of steel pipe piles connected to high-strength piles are used as the foundation piles, and the ready-made piles are placed in the ground. A reverse driving method for underground construction, characterized in that a structural pillar is erected on top of the ready-made pile after being driven into the interior. (2) When constructing a building with a basement underground, foundation piles are driven in advance at predetermined positions on the ground where the pillars of the building are to be erected, and above-ground construction is carried out above the structural pillars erected on top of the foundation piles. At the same time, in the reverse driving method for underground construction, which involves cutting down roots and placing concrete from the upper level of the basement to the lower level, ready-made piles consisting of high-strength piles and concrete piles with outer shell steel pipes are used as the foundation piles. A reverse driving method for underground construction, characterized in that after ready-made piles are driven into the ground, structural pillars are erected on top of the ready-made piles. (3) Claim 1 characterized in that the structural pillar is fixedly installed by injecting a foot hardening fixing liquid into the ready-made pile.
or 2. The reverse pouring method for underground construction as described in any of the above.