JPH10121490A - Building structure utilizing pile as pillar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with deformation of piles during an earthquake by positioning piles with their lower portions in the ground and with their upper portions projected above the ground, and by applying ground improvement treatment to the ground surface layer. SOLUTION: A hole 4 is bored with a boring tool such as an earth auger so that the fore-end of the hole 4 reaches a support layer 3a of a ground in a site 1. Next, a pile 6 is inserted into the hole 4 which is simultaneously filled with cement milk 5. Here, the pile 6 is not inserted to its full length but its upper portion projects above the ground so that its top end reaches up to the ceiling height of a building structure 2 to constitute a pillar 7 of the building structure 2. An improved ground layer 8 is formed by injecting solidification agent from the ground surface into the surface layer 3b of the ground 3. When a ground floor concrete 9 is deposited as a floor slab, a specified gap is provided around the pile 6 to isolate the concrete 9 from the pile 6 and to prevent the pile 6 and the floor slab from being damaged during the earthquake.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a building structure using a stake as a pillar as it is, and more particularly to a building structure suitable for a low-rise store or warehouse.

[0002]

2. Description of the Related Art As a conventional building structure of this type, a flat pile (two or more floors) is placed on a rising portion of a concrete pile driven into the ground (a portion projecting upward from the ground surface, that is, a column). (Japanese Patent Application Laid-Open No. Hei 6-81342) has been proposed to support the floor or ceiling of the vehicle and to not provide a foundation (foundation footing).

[0003]

According to the above-mentioned means, the foundation footing is not required, but the underground beams connecting the piles are indispensable for securing the required strength of the building structure. However, since the underground beam is buried in the ground, the construction is complicated and requires a considerable construction period. On the other hand, if the surface layer of the ground is improved, etc., it is thought that the required strength of this type of building structure can be secured without the underground beam,
In that case, it is necessary to further consider the deformation of the pile during an earthquake.

[0004] Therefore, there is a technical problem to be solved in order to deal with the deformation of the pile during an earthquake regardless of the presence or absence of underground beams, while ensuring the required strength of this type of building structure. The invention aims to solve the problem.

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned problems, and has a structure in which a lower portion of a pile is located in the ground and an upper portion of the pile is projected above the ground to form a pillar. Further, in some cases, a building structure is provided in which a surface slab of the ground is ground-modified and a floor slab laid on the ground and the pile are cut off.

[0006]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described in detail with reference to FIG. FIG. 1 shows a state in which a frame of a building structure 2 has been constructed on a site 1, and excavation holes 4,
4 are excavated with an excavator such as an earth auger, and the tip of the excavator reaches the support layer 3a. And the drilling holes 4, 4
… With cement milk 5 inside,
Embed ... The piles 6, 6,... May be concrete piles such as PHC piles, PRC piles, steel pipe wound PC piles, steel pipes, H-section steels, etc., and the types and materials thereof are not particularly limited. Further, instead of embedding the pile 6, the pile 6 may be driven.

The piles 6, 6,... Are not buried in the whole length, but project upward from the ground and reach the ceiling to the ceiling height of the building structure 2. The pillars 7 of the building structure 2 are formed. In this way, when a pile serving as a foundation of a building structure is used as a column as it is, there is a problem whether the pile (column) can secure required strength against the weight of the building structure, horizontal force due to an earthquake, and the like.

Therefore, the inventor analyzed pile deformation due to external force using the model shown in FIG. Specifically, the wire L is considered as a model of the pile, and the total length of the wire L is 1300.
It was set to 0 mm, and 9000 mm was driven into the ground to protrude 4000 mm above the ground. The tip (lower end) of the wire L is supported by a pin, and a portion buried in the ground is equivalent to the elastic restoring force received by the pile from the ground, and a total of nine springs k ₁ , k ₂ . k ₉ to 1000
They were connected horizontally at mm intervals. Further, an axial force P and a horizontal force H were applied to the top end of the wire L as external forces.

From the results of the case study, the spring k ₁ , k ₂ ... K ₉ , which has the highest degree of controlling the deformation mode of the wire L, is the uppermost spring k ₁ and the remaining springs k ₁ , k 2. _{2 ~k 9} was found to influence the degree is small. That is, when the spring constants of these springs k ₁ , k ₂ ... K ₉ are set to various sizes, and how the deformation mode of the wire L changes is examined, the spring constant of the spring k ₁ changes. However, the deformation mode of the wire L also greatly changes, but only by changing the spring constants of the other springs k _{2 to} k _9, no significant change was found in the deformation mode of the wire L.

[0010] This means that in a building structure using actual piles as pillars, if only the ground characteristics of the surface layer (about 1 m deep from the surface of the ground) can be accurately evaluated, the deformation of the pillar portions This means that the amount can be controlled, and as a result, the required strength of the building structure can be sufficiently secured. By the way, even if the spring constant for each depth is determined from the boring data of the ground and is applied to the above-described analysis model, reliable evaluation cannot be expected because the variation of the boring data itself is large. However, if the evaluation target is only the surface layer, such a problem is also solved.

That is, as shown in FIG. 1, the surface layer 3b of the ground 3
The ground is improved by injecting a solidifying agent from the ground surface.
The depth of the ground improvement portion 8 is approximately 1 m, but is increased or decreased according to the height of the building structure 2, the load applied to the columns 7, and the physical properties (hardness and the like) of the solidifying agent. Site 1
It is best to improve the ground over the entire surface, but it is economical if it is formed in a grid shape connecting the piles 6, 6 ... vertically and horizontally as shown in Fig. 3, and it has the same effect as an underground beam. It is also functionally excellent. Further, as shown in FIG. 4, the piles 6 may be formed so as to surround the periphery thereof.

By artificially improving the surface layer 3b as described above, it is possible to accurately evaluate the ground characteristics while increasing the rigidity of the surface layer 3b. Thus, pillars 7, 7 ...
Can be controlled, and therefore the required strength of the building structure 2 can be sufficiently secured even without the underground beam.

On the other hand, although the rigidity of the surface layer 3b is increased, the ground improvement portion 8 is more flexible than the underground beam, so that the piles 6, 6,. growing. Therefore, as shown in FIG. 1 and FIG. 5, when the concrete slab 9 is laid as a floor slab laid on the ground surface, a gap of about several mm to several cm around the piles 6, 6. , 10...) To cut off the concrete 9 between the soil and the piles 6, 6,. Thereby, even if the piles 6, 6, ... are deformed by the earthquake, they do not come into contact with the concrete between the soils 9, and therefore, the piles 6, 6, ... and the concrete between the soils 9 are not destroyed.

After that, as shown in FIG. 1, the girder 11, 11,... Are erected on the top ends of the columns 7, 7,. The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0015]

As described above, according to the present invention, the floor slab laid on the ground surface and the pile are cut off, so that the pile does not come into contact with the floor slab even if it is deformed by an earthquake. Slab destruction can be prevented. Further, by improving the surface layer of the ground, the required strength of this type of building structure can be sufficiently ensured even if there is no underground beam.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a perspective view of a building structure using a pile as a pillar.

FIG. 2 is an explanatory diagram of an analysis model for examining a deformation of a pile due to an external force.

FIG. 3 is a plan view showing an example of ground improvement.

FIG. 4 is a plan view showing another example of ground improvement.

FIG. 5 is a longitudinal sectional view of a main part around the ground surface.

[Explanation of symbols]

 2 Building structure 3 Ground 3b Surface 6 Pile 7 Pillar 8 Ground improvement part 9 Soil concrete 10 Edge cutting part

Claims (2)

[Claims] The present invention is characterized in that a lower part of a pile is located in the ground, an upper part of the pile is protruded to the ground to form a pillar, and a floor slab laid on the surface of the ground and the pile are cut off. A building structure that uses piles as pillars. 2. A floor slab laid on the ground surface, wherein a lower portion of the pile is located in the ground, an upper portion of the pile is projected above the ground to form a pillar, and a surface layer of the ground is improved for the ground. A building structure using a pile as a pillar, characterized in that the pile is cut off from the pile.