JPH05125736A - Structure of precast foundation - Google Patents

Abstract

PURPOSE:To simplify in-situ operation and save labours and further always secure a certain definite quality, by making aggregate layers and foam-resin layers in turn from the lower side on the bottom of an excavated hole and arranging a precast foundation body thereon and fixing it. CONSTITUTION:Aggregates like gravels are laid down on the bottom of an excavated hole 1 and they are fastened to form an aggregate layer 2 with a specified thickness. Granular-foamed styrene or the like is compactly stuffed to form the first foamed resin layer 3a. And then a rectangular molding-plate having the same qualitative material as the foamed resin layer 3a is placed on the foamed resin layer 3a to form the second foamed resin layer 3b. And a precast foundation body 4 fabricated in advance in a factory is transferred and installed on the layer 3b and connected and fixed to the ground G through piles 7. In this way, it becomes unnecessary to apply cast-in-place concrete and this simplifies in-situ operation and spares labours and reduces the construction period. And further, this is not influenced by weather or environment and a certain specified quality can be always obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a precast foundation that is preferably used in a construction method in which a precast foundation body is manufactured in advance in a factory or the like and is constructed on site.

[0002]

2. Description of the Related Art Conventionally, when building a foundation,
Generally, the following construction procedure is adopted. That is, specifically, first, a root cutting hole is dug at the site, an aggregate such as split stone is laid on the bottom, and then waste concrete is formed on it. After the waste concrete is hardened, a mold having a predetermined shape is arranged on the concrete, and the concrete is poured in a state where necessary reinforcing bars and the like are provided inside the mold. And after curing the concrete for a certain period,
The formwork is dismantled to obtain the desired foundation.

[0003]

However, in such a construction method, since the foundation is roughly formed on-site, the actual construction is complicated and labor saving cannot be expected. In addition, it is often found that it is difficult to keep the quality of the obtained foundation constant at all times, and the quality of the obtained foundation varies depending on conditions such as weather and environment.

Further, there is a problem that it takes a long time to cure the concrete cast in-situ, the construction period is prolonged, and the construction cost is increased accordingly.

The present invention has been made in view of the above circumstances, and by manufacturing a precast foundation body in a factory or the like, the precast basic body can be simplified so that a certain quality can always be ensured. It is intended to provide the foundation structure.

[0006]

According to the structure of the precast foundation of the present invention, the aggregate layer and the foamed resin layer are provided in this order from the bottom of the root cutting hole, and the precast foundation body is arranged and fixed on the aggregate layer and the foamed resin layer. By doing so, the above problem is solved.

[0007]

According to the structure of the precast foundation of the present invention, the precast foundation body pre-manufactured in a factory or the like is used, so that it is possible to eliminate the in-situ casting of concrete and to simplify the on-site construction. The basic quality can always be kept constant regardless of the environment and other conditions. Also, by eliminating the on-site casting of concrete,
It is possible to shorten the construction period by omitting the concrete curing period.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the precast foundation of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the structure of the precast foundation, and an aggregate is laid on the bottom of the root cutting hole 1 dug on site. As the aggregate, rubble stones, rubble stones and the like generally used for constructing a foundation are used. Then, the aggregate is compacted from above to form the aggregate layer 2 having a predetermined thickness (about 10 to 15 cm).

A foamed resin layer 3 made of foamed resin is provided on the aggregate layer 2. The foamed resin layer 3 is composed of a first foamed resin layer 3a made of granular foamed resin and a second foamed resin layer 3b made of a plate-shaped molded body of foamed resin.

Styrofoam is mainly used for the foamed resin forming the first foamed resin layer 3a, and the aggregated layer 2 is formed into a granular shape having an appropriate particle size (for example, about 10 to 15 mm). It is laid so as to be packed as densely as possible and has a thickness of about 15 to 20 cm. As the foamed resin, in addition to the polystyrene foam, for example, foamed polyethylene, foamed polyurethane, foamed polyvinyl chloride, foamed phenol resin, or the like may be used.

Also, the foamed resin forming the second foamed resin layer 3b is mainly made of the same material as that of the first foamed resin layer 3a, and has a thickness of, for example, about 20 to 25 cm and the above. A rectangular plate having a width substantially equal to the width of the root cutting hole 1 is placed and laid on the first foamed resin layer 3a.

A precast base body 4 is placed on the foamed resin layer 3 thus provided. As shown in FIG. 2, the precast foundation body 4 has a substantially rectangular plate-shaped footing portion 4a at the bottom and a substantially rectangular plate-shaped column base portion 4b standing on the footing portion 4a. It is configured as a main body, and is integrally molded in advance by pouring concrete using a predetermined formwork or the like in a factory or the like. A smooth slope is provided at the joint between the footin portion 4a and the column base portion 4b. A plurality of grooves 5 are formed in parallel at predetermined intervals so as to extend from the inclined surface to the upper surface of the footing portion 4a and smoothly extend along the inclined surface. Each of these grooves 5 is provided with a through hole 6 penetrating the footin portion 4a in its thickness direction.

The precast base body 4 thus constructed is installed with its fuchin portion 4a placed on the foamed resin layer 3 and the upper portion of the column base portion 4b protruding above the root cutting hole 1. Has been done. Then, a pile (reinforcing bar) 7 is driven into the through hole 6 of the footing portion 4a from above. The pile (reinforcing bar) 7 penetrates the through hole 6 and further penetrates the second foamed resin layer 3b, the first foamed resin layer 3a and the aggregate layer 2 thereunder to reach the ground G. The precast foundation body 4 and the ground G are connected and fixed to each other.

The precast foundation body 4 has both sides of the fuchin portion 4a filled with the same aggregates 8 such as rubble stones and crushed stones as described above, and is left on both sides of the column base portion 4b. The soil 9 is backfilled and compacted in the formed gap until reaching the upper surface of the root cutting hole 1, and the root cutting hole 1 is filled with these.

Next, a construction method for obtaining the structure of the precast foundation of this embodiment will be described in the order of steps with reference to FIGS. 3 to 8.

First, a root cutting hole 1 having a predetermined depth is dug on the site (FIG. 3).

Aggregates such as rubble stones and crushed stones are laid on the bottom of the root cutting hole 1 and compacted to form an aggregate layer 2 (FIG. 4).

Granular styrofoam (foam resin) is laid on the aggregate layer 2 to form the first foam resin layer 3a (FIG. 5).

On the first foamed resin layer 3a, a plate-shaped molded body made of expanded polystyrene is placed, and the second foamed resin layer 3 is formed.
Form b (FIG. 6).

On the second foamed resin layer 3b, the precast base body 4 having the above-mentioned structure which has been prepared in advance at a factory is carried in and installed. Then, the second foamed resin layer 3b, the first foamed resin layer 3a, and the aggregate layer 2 are penetrated from the through holes 6 of the footin portion 4a, and the pile G is pierced to the ground G below the pile. (Reinforcing bar) 7 is driven in to connect and fix the precast foundation body 4 and the ground G (FIG. 7).

Fuchin portion 4a of the precast base body 4
The aggregates 8 such as rubble stones and crushed stones are filled in the gaps on both sides of the (FIG. 8).

Further, the soil 9 is backfilled and compacted in the gaps on both sides of the column base 4b of the precast foundation body 4 to complete the construction of the precast foundation 4, and the structure of the precast foundation as shown in FIG. To get

As described above, according to the structure of the precast foundation of this embodiment, since the precast foundation main body 4 preliminarily manufactured in the factory or the like is used, the on-site construction of concrete can be eliminated and the on-site construction can be eliminated. Can be simplified and labor can be saved. Further, therefore, it is possible to provide the structure of the precast foundation which always secures a certain quality regardless of the conditions such as weather and environment.

Further, by eliminating the in-situ casting of concrete, it is possible to save the labor and time for curing the concrete on the site, shorten the construction period and reduce the cost accordingly.

Further, since the aggregate layer 2 and the foamed resin layer 3 are provided at the bottom of the root cutting hole 1 in place of the conventional waste concrete, the ground G supporting the precast foundation body 4 can be easily formed. Can be improved. Further, by providing the foamed resin layer 3, it is possible to achieve a significant weight reduction and cost reduction as compared with the conventional discarded concrete. Moreover, since the foamed resin layer 3 is composed of the first foamed resin layer (lower layer) 3a made of granular foamed resin and the second foamed resin layer (upper layer) 3b made of the plate-shaped molded body, the ground G And the workability when installing the precast foundation body 4 thereon is improved.

Further, since the through hole 6 is provided in the footin portion 4a of the precast foundation body 4, if the pile (reinforcing bar) 7 is driven in by using this through hole 6, the precast foundation body 4 can be easily and firmly formed. Can be connected and fixed to the ground G. Furthermore, if the through hole 6 is attached by hooking a wire or a rope on the through hole 6, when the precast foundation 4 is transported from the factory to the site, or when the precast foundation body 4 is lifted at the site and carried into a predetermined position, etc. Also, it can be suitably used.

FIG. 9 shows a second embodiment of the present invention. The difference between this embodiment and the first embodiment described above is that the fuchin portion 4a is provided only on one side of the column base portion 4b,
Also, a plurality of points along the tip direction of the footin portion 4a provided on one side of this are fixed by the piles 7.

That is, the Fuchin portion 4a of this embodiment.
Is formed wider than that on one side of the column base portion 4b of the first embodiment, and at two locations (of course, three or more locations may be provided) along the tip direction of the portion thus formed wider. A through hole 6 is formed, and the footin portion 4a is fixed by a pile 7 penetrating the through hole 6. The groove 5 formed in the footin portion 4a may be formed as wide as necessary in order to obtain a good drainage property with respect to the upper portion of the pile 7, and is formed in a taper shape that gradually becomes wider toward the tip. May be. Furthermore, when bolts are used as the piles 7, a structure may be provided at the upper end of the through hole 6 to provide a hole for embedding a bolt head or a nut.

It is needless to say that this embodiment can obtain the same effect as that of the above-mentioned embodiment, but especially when it is not possible to secure a space for embedding the footin portion 4a on one side of the column base portion 4b. There are merits.

The structure of the precast foundation of the present invention is not limited to the above-mentioned embodiments, but the shape of each member,
Specific constitutional requirements such as materials, dimensions, and construction procedures can be changed as appropriate during implementation.

For example, in each of the above-mentioned embodiments, an example is shown in which the gaps on both sides of the column base portion 4b of the precast foundation body 4 are filled with the soil 9 which is backfilled, but instead of backfilling,
It is also possible to cast concrete.

[0033]

As described above, according to the structure of the precast foundation of the present invention, since the precast foundation body pre-manufactured in the factory or the like is used, the in-situ casting of concrete as in the conventional construction is eliminated, It is possible to simplify on-site construction and save labor. Therefore, it is possible to always ensure a certain quality regardless of the conditions such as weather and environment. In addition, by eliminating the in-situ casting of concrete, it is possible to save the labor and time of curing the concrete on the site, and shorten the construction period. Further, instead of the conventional waste concrete, an aggregate layer and a foamed resin layer are provided in the root cutting hole, so that the ground supporting the precast foundation body can be easily improved, and a large amount can be obtained. It is also possible to reduce the weight and cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the structure of a precast foundation of the present invention.

FIG. 2 is a perspective view showing a precast foundation body used in the structure of the precast foundation.

FIG. 3 is a sectional view illustrating a construction procedure for obtaining the structure of the precast foundation and showing a state of the foundation when a root cutting hole is dug in the ground.

FIG. 4 is a cross-sectional view showing a state of the foundation at a stage where an aggregate layer is provided on the bottom of the root cutting hole.

FIG. 5 is a cross-sectional view showing the state of the foundation at the stage when the first foamed resin layer is provided.

FIG. 6 is a cross-sectional view showing a state of the foundation at a stage where a second foamed resin layer is provided.

FIG. 7 is a cross-sectional view showing the state of the foundation at the stage when the precast foundation body is installed and fixed on the foamed resin layer.

FIG. 8 is a cross-sectional view showing a state of the precast foundation at the stage where the side portion of the precast foundation is filled with the aggregate.

FIG. 9 is a sectional view showing a second embodiment of the structure of the precast foundation of the present invention.

FIG. 10 is a perspective view showing a precast foundation body used in the structure of the precast foundation.

[Explanation of symbols]

 1 Root cutting hole 2 Aggregate layer 3 Foamed resin layer 4 Precast foundation body

Claims (1)

[Claims] 1. A structure of a precast foundation, wherein an aggregate layer and a foamed resin layer are provided in order from the bottom at the bottom of the root cutting hole, and a precast foundation body is arranged and fixed on the aggregate layer and the foamed resin layer.