JPH06116965A - Well frame foundation - Google Patents

Abstract

PURPOSE:To reduce cost by bearing the load of a structure in an upper section by a foundation improvement section, transmitting the load to a bearing ground and using a well frame in an extent that horizontal force working to the foundation improvement section is born. CONSTITUTION:The periphery of a foundation improvement section 2, on an upper section of which a structure 1 is loaded, is surrounded by a well frame 3, which is made of cast-in-place concrete or iron and on an upper section of which the structure 1 is not loaded, thus constituting a well frame foundation A. Accordingly, the load of the structure 1 in the upper section is received by the foundation improvement section 2 and transmitted to a bearing ground 4. An extension to the side of the foundation improvement section 2 is prevented by the well frame 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an envelope frame foundation.

[0002]

2. Description of the Related Art Conventionally, a concrete enclosing frame 3 and a ground improvement portion 2 therein are formed on a ground 7 to enclose an enclosing frame foundation A.
It is known that In this envelope frame foundation A, as shown in FIG. 4, the upper structure 1 is loaded on the envelope frame 3 and the ground improvement section 2 inside thereof, and the load of the upper structure 1 is applied to the envelope frame. 3 and the ground improvement section 2 inside thereof are simultaneously responsible.

[0003]

However, since the internal ground improvement portion 2 is inferior in rigidity as compared with the surrounding concrete surrounding frame 3, the upper structure 1 is surrounded by the surrounding frame 3 as in the prior art.
In the structure in which the ground improvement section 2 and the ground improvement section 2 therein are loaded as shown in FIG. 4, most of the load from the upper structure 1 is borne by the highly rigid envelope frame 3 as shown by the arrow in FIG. Will be transmitted to the lower support ground 4, and as a result, the ground improvement section 2
Does not function as an effective load transmission means. In addition, in the outer peripheral envelope frame 3, mainly the upper structure 1
It is difficult to say that the lower surface part of the upper structure 1 that is loaded on the foundation is uniformly and stably supported, because the load is supported and transmitted.

On the other hand, in this type of foundation, the supporting force is such that the larger the bottom area of the portion for transmitting the load to the support ground 4, the larger the supporting force, and the smaller the bottom area, the smaller the supporting force. In the conventional example as described above, most of the load is transmitted to the supporting ground by the surrounding frame,
The size of the bottom area of the envelope frame greatly affects the bearing capacity. However, if the bottom area of the envelope frame formed of cast-in-place concrete or the like is increased (for example, the wall thickness of the envelope frame is increased), there is a problem that the cost is significantly increased.

The present invention has been made in view of the above-mentioned problems of the conventional example, and an object thereof is to support the load of the upper structure by the ground improvement portion and transmit the load to the supporting ground. The envelope frame is only required to bear the horizontal force acting on the ground improvement part, and it is to provide the envelope frame foundation which can reduce the cost.

[0006]

In order to solve the problems of the above-mentioned conventional examples and to achieve the object of the present invention, the envelope frame foundation of the present invention comprises a ground improvement portion 2 on which a structure 1 is loaded. Structure 1 around the top of the cast-in-place concrete or iron
It is characterized in that it is surrounded by an envelope frame 3 which is not loaded.

Further, the lower end portion of the ground improvement portion 2 is the supporting ground 4
Therefore, it is also preferable that the ground improving portion 2 has a strength substantially equal to or higher than that of the supporting ground 4 or a strength capable of withstanding the vertical force of upper loading. Also,
It is also preferable that the envelope frame 3 has a strength capable of withstanding the horizontal force of the ground improvement portion 2.

[0008]

According to the present invention having the above-described structure, however, the structure 1 is placed on the upper part of the cast-in-place concrete or iron around the ground improvement part 2 on which the structure 1 is loaded.
Since the structure is surrounded by the envelope frame 3 which is not loaded, the load from the upper structure 1 is borne by only the ground improvement part 2, while the load from the upper structure 1 to the side of the ground improvement part 2 is increased. Restrain the spread of the ground by the envelope frame 3 to cut off the influence on the surrounding ground,
The load of the upper structure 1 acting on the ground improvement section 2 is reliably transmitted to the support ground 4. Moreover, the ground improvement section 2
By loading the upper structure 1 only on the upper part, the portion of the lower part of the upper structure 1 loaded on the foundation is uniformly and stably supported. Further, the support load can be increased by increasing the bottom area of the support ground 2.

Further, the lower end portion of the ground improvement portion 2 is a supporting ground 4
And the strength of the ground improvement portion 2 is improved to a strength substantially equal to or higher than that of the support ground 4 or a strength capable of withstanding the vertical force of upper loading, whereby the above-mentioned action, that is, the upper portion The load of the structure 1 can be supported by the ground improvement portion 2 and reliably transmitted to the support ground 4. Also,
By making the envelope frame 3 strong enough to withstand the horizontal force of the ground improvement part 2, the lateral extension of the ground improvement part 2 from the upper structure 1 is restricted by the envelope frame 3 to the surrounding ground. In addition to being able to eliminate the influence of the above, it is not necessary to make the envelope frame 3 stronger than necessary, and the cost can be reduced.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the accompanying drawings. The envelope foundation A of the present invention is composed of a ground improvement portion 2 formed on the ground 7 and an envelope frame 3 surrounding the ground improvement portion 2. Here, various methods are conceivable for forming the envelope base A. For example, the envelope frame 3 is made of cast-in-place concrete so as to enclose the earth and sand in the place where the envelope foundation A of the ground 7 is to be formed while leaving the earth and sand inside.
Then, the interior surrounded by the envelope frame 3 is ground-improved to form the ground-improved portion 2. Further, as another example, the portion of the ground 7 on which the envelope foundation A is to be formed is ground-improved to form the ground improvement portion 2, and then the surrounding area of the ground improvement portion 2 is made of cast-in-place concrete to form an envelope frame. 3 is formed. Further, as another example, when the place where the envelope foundation A of the ground 7 is to be formed is improved to form the ground improvement part 2, the envelope frame 3 is formed on the outer periphery of the ground improvement part 2 at the same time. .

Various methods can be used to form the ground improvement portion 2. For example, the ground 7 is broken by a crushing machine 5 as shown in FIG. Caking liquid (for example, cement milk, a mixed liquid mainly composed of cement milk, a cooled carbon dioxide-containing cement mixed liquid, or other various solidifying liquids) from a jet port provided near the tip. The ground is improved by jetting or discharging the liquid) and stirring and mixing the crushed soil and the liquid for consolidation by the stirring means 6 provided on the rotating vertical axis 8 of the crusher 5. Of course, the ground improvement part 2 can be formed by various ground improvement methods other than this. In FIG. 3, 9 is a bit.

Further, in forming the envelope frame 3,
It is conceivable to use a conventionally known cast-in-place concrete underground wall forming machine to construct the cast-in-place concrete to form the envelope frame 3, but the present invention is not limited to this, and is made of metal such as iron. It is also possible to embed a thing or a concrete thing formed on the ground at a predetermined position of the ground 7 to form the envelope frame 3.

Further, in the above, a casing is provided so as to surround the rotating vertical axis 8 of the crushing machine 5, the ground is crushed by the crushing machine 5, and the crushing soil and the consolidation liquid are mixed by the stirring means 6. Is mixed by stirring to improve the ground, and at the same time, the casing is embedded, and when the ground improvement is completed and the rotary vertical axis 8 is withdrawn, the casing is left in the ground 7, and the casing is embedded so as to surround the ground improvement part 2. The casing serves as the envelope frame 3.

In any of the above-mentioned embodiments, the lower end of the ground improvement portion 2 reaches the support ground 4, and
The lower end of the envelope frame 3 also reaches the support ground 4. The strength of the ground improvement part 2 is substantially the same as or higher than that of the support ground 4, or the strength of the ground improvement part 2 is sufficient to withstand the vertical force of the upper load. Also,
The envelope frame 3 has strength enough to withstand the horizontal force of the ground improvement section 2. These are designed and obtained according to the condition of the ground 7 and the conditions of the upper structure 1, etc.

In the envelope foundation A having such a structure, the present invention is characterized in that the upper structure 1 is loaded only on the ground improvement section 2. That is, as shown in FIG. 1, the upper structure 1 only on the upper surface portion of the ground improvement portion 2 of the envelope foundation A.
The upper structure 1 is formed so that the upper structure 1 is loaded on the upper structure 1, whereby all the load of the upper structure 1 is supported by the ground improvement section 2 and transmitted to the supporting ground 4. There is. Then, the horizontal force acting on the ground improvement section 2 is restrained by the surrounding frame 3 formed around the ground improvement section 2 to prevent the ground improvement section 2 from spreading laterally, and serves as a basis for the ground improvement section 2. It has been designed to dramatically increase the support capacity of the. Here, as described above, since the envelope frame 3 has the strength capable of withstanding the horizontal force of the ground improvement portion 2, the strength of the envelope frame 3 is not required more than necessary (that is, the envelope frame 3 has (The strength of the upper structure 1 is not required.) As a result, for example, when forming the surrounding frame 3 with cast-in-place concrete, the thickness is not increased more than necessary, and The construction can be simplified and the cost can be reduced. On the other hand, the bottom area of the ground improvement section 2 must be the area necessary for supporting the upper structure 1 and transmitting it to the support ground 4, but compared to cast-in-place concrete, for example, Since it is formed as it is by mixing it with the congealing liquid and stirring it, the cost of forming the ground improvement part 2 having a wide bottom area is such that the bottom area of the envelope frame 3 formed by cast-in-place concrete is widened. The cost is much lower than that of the product, the construction is simplified, and it can be done in a short time.

The horizontal sectional shape of the envelope frame foundation A is shown in FIG.
In the embodiment shown in (1), the shape is circular, but the shape is not limited to this, and it is needless to say that various shapes such as a polygonal shape and an elliptical shape can be used according to the purpose.

[0017]

As described above, according to the present invention, the surrounding frame of the ground improvement section on which the structure is loaded is an enclosure frame which is made of cast-in-place concrete or iron and on which the structure is not loaded. Since it is surrounded by, the load from the upper structure is borne only by the ground improvement part, while the lateral spread of the ground improvement part from the upper structure is restrained by the surrounding frame to the surrounding ground. The load of the upper structure acting on the ground improvement part is reliably transmitted to the supporting ground, and as a result, the load of the upper structure is safely and surely supported by the ground improvement part. In addition, by loading the upper structure only on the ground improvement part, the lower surface part loaded on the foundation of the upper structure is uniformly and stably supported. Since the load on the upper part is supported only by the ground improvement part, it is possible to increase the supporting load by widening the bottom area of the ground improvement part. In this case, one that widens the bottom area of the ground improvement part. Therefore, it is possible to obtain a large supporting force at low cost.

Further, the lower end of the ground improvement portion reaches the support ground, and the strength of the ground improvement portion is improved to a strength substantially equal to or higher than that of the support ground or a strength capable of withstanding the vertical force of upper loading. With this structure, the load of the upper structure can be supported by the ground improvement section and reliably transmitted to the supporting ground with the most rational structure. Also, by making the envelope frame strong enough to withstand the horizontal force of the ground improvement part, the lateral spread of the ground improvement part from the upper structure is restrained by the envelope frame to prevent the influence on the surrounding ground. Not only can it be cut off, but it is not necessary to make the envelope frame stronger than necessary, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of the present invention.

FIG. 2 is a horizontal sectional view of the above.

FIG. 3 is a front view of the crushing machine used in the present invention.

FIG. 4 is a vertical sectional view of a conventional example.

[Explanation of symbols]

 1 Structure 2 Ground improvement part 3 Envelope frame 4 Support ground

Claims (3)

[Claims] 1. An enclosure frame characterized in that the ground improvement section on which a structure is loaded is surrounded by an enclosure frame made of cast-in-place concrete, iron or the like on which the structure is not loaded. Foundation. 2. The lower end of the ground improvement section reaches the support ground,
2. The envelope frame foundation according to claim 1, wherein the strength of the ground improvement portion is improved to a strength substantially equal to or higher than that of the supporting ground or a strength capable of withstanding the vertical force of the upper load. 3. The envelope frame foundation according to claim 1, wherein the envelope frame has a strength capable of withstanding the horizontal force of the ground improvement portion.