JPH05484B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for constructing a building having a basement floor, and more specifically, a method for constructing a building having a basement floor, and more specifically, a method for constructing a column-row retaining wall to perform excavation work on the basement floor. It concerns a method of constructing buildings that require support piles.

[Conventional technology]

Conventionally, when constructing a building that required supporting piles to perform underground floor excavation work by constructing column-row retaining walls, Support piles were placed inside.

[Problem that the invention seeks to solve]

When constructing a building on a small site with high land prices, such as in an urban area, the exterior walls and pillars on the ground floor are usually planned to fill the entire site, that is, to be located as far outside as possible. If the supporting piles are placed inside the underground outer wall, as in the case of will occur.

For this reason, foundation beams with large beams are required, the depth of excavation becomes deeper, and supporting structures such as retaining walls, cut beams, and uprights are also required on a large scale, which is necessary for underground construction. This was a factor that increased costs.

Also, from a structural perspective, there was a problem in that the distance between the piles was smaller than the width of the building, so the resistance to the overturning moment during an earthquake was reduced.

An object of the present invention is to solve the above-mentioned problems in the conventional example with a highly economical configuration.

[Means for solving problems]

The technical means taken by the present invention to achieve the above object are as follows. That is, in the method of constructing a building with a basement floor according to the present invention, a soil pile is constructed on the outer periphery of the building construction site to a position deeper than the final excavation bottom of the basement floor, and the soil pile has a length comparable to that of the soil pile. The permanent piles with steel pipe piles as upper piles and PHC piles as lower piles, which also serve as piles,
After constructing a column-row retaining wall with these permanent piles and soil piles located between the permanent piles by arranging the tips of the lower piles to reach the supporting layer, the inner side of the column-row retaining wall is constructed. The basement floor is constructed by excavating the ground, while the ground floor is constructed above the column retaining wall.

[Effect]

According to the above configuration, the permanent piles (supporting piles) are placed at the position of the pillar-row retaining wall and are also used as a retainer, so they are placed directly under the pillars on the ground floor built above the column-row retaining wall. The supporting piles will be placed at As the spacing increases, the resistance to the overturning moment during an earthquake also increases.

In addition, the above-mentioned permanent piles are made of steel pipe piles with high bending capacity for the upper piles, which are subjected to earth pressure during excavation work and horizontal force and bending moments during earthquakes, and are located deeper than the final excavation bottom of the basement floor. As for the lower piles, which mainly bear the axial force, PHC piles are used, which have inferior bending strength compared to steel pipe piles but are 30 to 50% cheaper, so they can be used both as retaining piles and supporting piles. Despite this, there is no waste of pile material, and the cost of piles is low.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings.

First, as shown in Figure 1A and Figure 2A, a column of soil piles 1 is constructed on the outer periphery of the building construction site to a position deeper than the final excavation bottom of the basement floor (indicated by the imaginary line p). do.

Next, as shown in FIG. 1B and FIG. 2B, while the soil pile 1 is not completely hardened, a steel pipe pile 2 having a length L comparable to that of the soil pile 1 is set as the upper pile _A1 , A permanent pile A with type B PHC pile 3 as the lower pile A ₂ is placed with the tip of the lower pile A ₂ reaching the support layer 4, and is connected to the permanent pile A. A column retaining wall B is constructed with soil piles 1 located between the permanent piles A. Said permanent pile A
A more specific explanation of the construction procedure is as follows. That is, as shown in Figure 3 A and B, after constructing a row of soil piles (so-called soil cement piles in which cement milk and excavated soil are mixed in an excavated hole) 1 using a 3-axis auger machine, Third
As shown in FIG. Inject 7. After that, as shown in Figure 3 D, lower the pile using a crawler crane, etc.
Suspend A ₂ into the stake hole 6 and temporarily hold it in place. In this state, using the crawler crane, etc., suspend the upper pile A ₁ above the lower pile A ₂ as shown in Figure 3 E, and weld the upper pile A ₁ and the lower pile A ₂ so that they are concentric. Connect in a shape. After that, this top pile A ₁
The permanent pile A consisting of the lower pile _A2 and the lower pile A2 is inserted to a predetermined position as shown in Fig. 3.

After constructing the pillar-row retaining wall B as described above, the ground inside the pillar-row retaining wall B is excavated to a predetermined depth as shown in Fig. 1(c). As shown in FIGS. 6 to 6, while a basement floor is constructed, a ground floor is constructed above the pillar row retaining wall B. 8 is the underground outer wall, 9 is the foundation bottom plate, 10
It is made of concrete, and 11 is the pillar on the ground floor.

To connect the steel pipe pile 2 and the PHC pile 3, for example, as shown in FIG. Welding is performed at several points in the circumferential direction, and this backing metal fitting 12 is placed on the ring-shaped end plate 3a of the PHC pile 3, and the three parts, the steel pipe pile 2, the backing metal fitting 12, and the ring-shaped end plate 3a, are welded W. This can be done by: In this case, the ring-shaped end plate 3a
If the thickness of the steel pipe pile 2 is small, the load of the steel pipe pile 2 will concentrate on the vicinity of the outer periphery of the ring-shaped end plate 3a, and there is a possibility that the concrete portion 3b immediately below the ring-shaped end plate 3a may be crushed.
In such a case, as shown in FIG. 8, another ring-shaped hardware 13 having a predetermined thickness is welded to the upper surface of the ring-shaped end plate 3a in advance, and the steel pipe pile 2,
If the backing hardware 12 and the ring-shaped hardware 13 are welded together, the load of the steel pipe pile 2 will be distributed in a distributed manner, so a special PHC pile 3 with a thick ring-shaped end plate 3a will be used. Even without it, that is, even if the existing mass-produced PHC piles 3 are used, the above-mentioned crushing of the concrete portion 3b can be prevented.

In the illustrated embodiment, since there is no pile at the position of the foundation bottom plate 9, the foundation bottom plate 9 can be designed as a water pressure resistant plate, and the thickness of the plate can be reduced.
In addition, in the illustrated embodiment, the lower pile A ₂ has appropriate lengths l ₁ and l ₂
It is constructed by adding two PHC piles 3,
1. It may be genuine. Upper stake _A1 is also on the drawing,
1 A real steel pipe pile 2 is shown, but the upper pile A ₁ may be constructed by adding a plurality of steel pipe piles.

〔Effect of the invention〕

Since the present invention has the above-described configuration, it can achieve the following effects.

A permanent pile (supporting pile) is placed at the position of the column retaining wall and serves as a retainer, so the supporting pile is placed directly below the pillar on the ground floor built above the column retaining wall. As a result, the eccentric moment due to misalignment between the column center and the pile center is reduced, and a foundation beam with a large beam thickness is not required.

Therefore, not only the number of building blocks decreases, but also
The excavation depth can be reduced, and supporting structures such as struts and erecting can be simplified.

The permanent pile is subjected to earth pressure during excavation work,
The upper pile, which is subjected to horizontal force and bending moment during an earthquake, is a steel pipe pile with a high bending capacity, and the lower pile, which is located deeper than the final excavation bottom of the basement floor and mainly bears the axial force, is a steel pipe pile with a high bending capacity. Although it has inferior bending strength, it is 30 to 50% cheaper.
Since PHC piles are used, there is no wastage of pile material even though they are used as piles and support piles, and the cost of piles is low. Significant cost reductions are possible.

Since the permanent piles are located outside the underground outer wall, the distance between the piles becomes larger, which increases the resistance to the overturning moment during an earthquake.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIGS. 1A to 2D are schematic longitudinal cross-sectional views illustrating a method of constructing a building having a basement floor, FIGS. 2A and 2B are schematic longitudinal sectional front views, and FIG.
Figures A to F are explanatory diagrams of the construction procedure for the permanent piles, and Figure 4 is a cross-sectional view of the building at the time the basement floor was constructed.
Fig. 5 is a longitudinal cross-sectional view of the main part, Fig. 6 is a cross-sectional view of the main part, and Figs. 7 and 8 are cross-sectional views of the main part showing the connecting part between the steel pipe pile and the PHC pile. A...Permanent pile, _A1 ...Top pile, _A2 ...Lower pile, B
...Pillar row retaining wall, 1...Soil pile, 2...
Steel pipe pile, 3...PHC pile.

Claims (1)

[Claims] 1. Construct a soil pile around the outer periphery of the building construction site to a depth deeper than the final excavation bottom of the basement floor, and construct a pile with steel pipe piles of similar length to the soil pile as the upper pile and PHC piles as the lower pile. After arranging permanent piles that also serve as a stopper with the tips of the lower piles reaching the support layer and constructing a column-row retaining wall with these permanent piles and soil piles located between the permanent piles, A method for constructing a building having a basement floor, characterized in that a basement floor is constructed by excavating the ground inside the column-row retaining wall, and a ground floor is constructed above the column-row retaining wall.