JP7314432B1 - Foundation structure of building and construction method of foundation structure - Google Patents

Abstract

The present invention provides a building foundation structure that can easily ensure the strength, durability, etc. of the supporting ground when backfilling the inside of an existing underground frame to form the supporting ground. SOLUTION: In a foundation structure 1 of a building 2, the inside of a wall 112 of an existing underground skeleton 11 having a floor 111 and a wall 112 on its outer periphery is filled with a refilling material 13. The refilling material 13 is a fluid material, and the building 2 above the refilling material 13 and the upper part of the wall 112 are connected by the reinforcing floor 3 . The building 2 is provided on the upper surface of the refilling material 13, and the reinforcing floor 3 is provided between the building 2 and the wall 112. - 特許庁[Selection drawing] Fig. 1

Description

Application of Article 30, Paragraph 2 of the Patent Act [Place of publication] Akashi-cho, Chuo-ku, Tokyo [At the time of publication] June 2022

TECHNICAL FIELD The present invention relates to a building foundation structure, etc., in which the inside of an existing underground skeleton that has been backfilled is used as supporting ground.

There are refilled areas (land) where the existing underground framework such as pressure slabs and earth pressure walls are left unbroken underground, filled with refilling materials such as crushed stones and framework debris, and the ground surface is paved with asphalt, etc., and used for parking lots and other purposes.

In addition, Patent Document 1 discloses a technique for backfilling the underground structure of an old building with demolished concrete debris from the old building, solidifying it with mortar or the like to form a supporting ground, and building a new building on top of it, with the aim of reducing construction costs.

JP-A-11-350746

The vertical load applied to the backfilling location acts as a lateral pressure from the inside on the earth pressure wall of the existing underground skeleton through fluid crushed stone, skeleton debris, or the like. The lateral pressure is usually resisted (cancelled) by the lateral pressure applied from the ground outside the earth pressure wall. However, if the outside of the earth wall is a water area such as a river or ground that may liquefy, or if it is hollow due to excavation or the like, lateral pressure from the outside cannot be expected.

Regardless of the case where the backfilled area is used for a parking lot or the like, when building a new building using the backfilled area as the supporting ground as in Patent Document 1, lateral pressure from the outside cannot be expected, which is a problem in the strength and durability of the supporting ground.

As a technique capable of solving the above problems, it is conceivable to fill the gaps of crushed stones, crushed wastes, etc. with mortar or the like as in Patent Document 1, and solidify and integrate the crushed stones, crushed wastes, etc. However, it is difficult to confirm filling of mortar and the like, and it is difficult to ensure quality.

It is also conceivable to refill with concrete or the like after removing crushed stones, crushed debris, etc., and use the solidified concrete or the like as the supporting ground. However, in this case, the construction period for forming the supporting ground becomes longer. In addition, since it is necessary to remove and carry out crushed stones, crushed pieces, etc. (handled as industrial waste disposal, etc.), it is time-consuming and costly. In addition, large heavy machinery and work platforms are required to remove crushed stones and crushed debris from underground.

On the other hand, it is also conceivable to drive piles from the ground so as to penetrate the existing underground frame and support the new building with their bearing capacity. However, in this case, the construction period will be longer due to the need for the pile-driving process. In addition, depending on the condition of the remaining structure inside the existing underground structure, it may be necessary to remove the structure. Furthermore, large-scale heavy machinery work (pile driving work using a pile driver, etc.) is also required in a narrow site.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a building foundation structure that can easily secure the strength and durability of the supporting ground when the inside of the existing underground skeleton is backfilled to form the supporting ground.

A first invention for solving the above-mentioned problems is a foundation structure of a building , in which the inside of the wall of an existing underground skeleton having a floor and a wall on the outer periphery thereof is filled with refilling material, the refilling material is a material having fluidity, and the building above the refilling material and the upper part of the wall are connected by a connecting portion, and in the foundation structure, the surcharge of the building is supported only by the supporting ground composed of the existing underground skeleton and the refilling material. It is a foundation structure of a building characterized by being
The connecting part is, for example, a reinforcing floor, and the reinforcing floor is composed only of a plate-like portion. Alternatively, the reinforced floor may have a plate-like portion and a beam-like member provided between the building and the wall and extending along the wall in a plane.

In the present invention, when the inner side of the wall of the existing underground skeleton is filled with backfill material to serve as the supporting ground for a new building, the upper part of the wall of the existing underground skeleton is connected to the building to ensure the degree of fixation of the upper part of the wall. As a result, the walls of the existing underground skeleton can be prevented from becoming cantilevered, and the stress generated in the walls due to the lateral pressure from the inner refilling material can be reduced. In the present invention, it is only necessary to reinforce the upper part of the wall of the existing underground skeleton, so there is no need to excavate a large amount of backfill material, and it is possible to carry out construction from the ground while leaving the inside of the existing underground skeleton as it is, which facilitates construction.

第２の発明は、床体とその外周部の壁体とを有する既存地下躯体の前記壁体の内側が埋戻材で充填され、前記埋戻材は流動性を有する材料であり、前記埋戻材の上方の建物と、前記壁体の上部とが連結部で連結され、前記建物は前記埋戻材の上面に設けられ、前記連結部である補強床が、前記建物と前記壁体の間に設けられ、前記補強床は、版状部分の外周部の下面に、平面において前記壁体に沿って延びる梁状部分を一体化したものであり、前記梁状部分が前記壁体の上部に接合されることを特徴とする基礎構造である。
第３の発明は、床体とその外周部の壁体とを有する既存地下躯体の前記壁体の内側が埋戻材で充填され、前記埋戻材は流動性を有する材料であり、前記埋戻材の上方の建物と、前記壁体の上部とが連結部で連結され、前記連結部である補強床が前記埋戻材の上面に設けられ、前記建物は前記補強床の上面に設けられ、前記補強床は、版状部分の外周部の下面に、平面において前記壁体に沿って延びる梁状部分を一体化したものであり、前記梁状部分が前記壁体の上部に接合されることを特徴とする基礎構造である。
As the connecting portion, the reinforcing floor described above can be used. In the former case, installing a reinforced floor between the building and the wall of the existing underground frame makes it possible to construct the reinforced floor after the building is constructed.

In the present invention, for example, the content of fine particles in the soil layer below the groundwater level of the ground outside the wall is 35% or less.
The present invention is particularly effective when applied under conditions where lateral pressure from the ground outside the existing underground skeleton cannot be expected temporarily or for a long period of time, and a typical example is when the outside ground has the above-described configuration and there is a risk of liquefaction.

The reinforced floors of the second and third inventions can secure the fixation of the upper part of the wall by the beam-like part, and transmit the bending stress of the upper part of the wall to the plate-like part as well as the beam-like part, resulting in a structure with high yield strength.

It is also desirable that the reinforced floor and the building are integrated with a joint material.
As a result, the connection state between the building and the walls of the existing underground frame can be ensured.

第４の発明は、床体とその外周部の壁体とを有する既存地下躯体の前記壁体の内側が流動性を有する埋戻材で充填された状態で、前記埋戻材の上方に建物を構築する際に、前記建物と前記壁体の上部とを連結部で連結する基礎構造の施工方法であって、前記埋戻材の上面に前記建物を設ける工程と、前記建物と前記壁体の上部とを連結するように前記連結部を構築する工程と、を含み、前記基礎構造において、前記建物による上載荷重は、前記既存地下躯体と前記埋戻材によって構成された支持地盤のみで支持されることを特徴とする基礎構造の施工方法である。
A fourth invention is the construction method of the foundation structure of the first invention.

Advantageous Effects of Invention According to the present invention, it is possible to provide a building foundation structure that can easily ensure the strength, durability, etc. of the supporting ground when the inside of the existing underground skeleton is backfilled to form the supporting ground.

The figure which shows the foundation structure 1 of the building 2. FIG. FIG. 4 is a diagram showing bending stress generated in the wall body 112; FIG. 4 is a diagram showing joints between a wall body 112 or a building 2 and a reinforced floor 3; The figure which shows the beam 15 and the column 16. FIG. The figure which shows the foundation structure 1a of the building 2. FIG. The figure which shows the position of the building 2. FIG.

Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an outline of a foundation structure 1 of a building 2 according to an embodiment of the invention. In this foundation structure 1, the inside of the existing underground skeleton 11, which is the underground portion of the existing skeleton 10, is filled with a refilling material 13, a reinforced floor 3 is provided on the upper surface of the refilling material 13, and the building 2 and the wall 112 of the existing underground skeleton 11 are connected by the reinforced floor 3.

The existing skeleton 10 is the skeleton of the existing building that was previously provided at the construction site of the building 2, and the existing underground skeleton 11, which is the underground portion, is formed of concrete, such as reinforced concrete or steel-reinforced concrete. The existing underground skeleton 11 is a box-shaped skeleton with an open top, and has a floor 111 such as a pressure plate and a wall 112 such as an earth pressure wall provided on the outer periphery of the floor 111 .

The backfilling material 13 is crushed debris, crushed stone, sand, etc. at the time of dismantling the above-ground part 12 of the existing skeleton 10, but is not particularly limited as long as it is a fluid material. Further, in this embodiment, the refilling material 13 is not solidified with mortar or the like as described above.

The reinforcing floor 3 is a plate-like member provided on the upper surface of the refilling material 13 and functions as a connecting portion that connects the building 2 and the wall 112 of the existing underground skeleton 11 . Although the reinforced floor 3 is made of reinforced concrete in this embodiment, it is not limited to this.

The building 2 is part of the upper surface of the refilling material 13, and is newly constructed in a space obtained by removing the ground part 12 of the existing frame 10.例文帳に追加The existing underground skeleton 11 and the refilling material 13 inside it function as supporting ground for the building 2 . The reinforcing floor 3 is provided only between the building 2 and the wall 112 of the existing underground skeleton 11 .

The structural form, shape, etc. of the building 2 are not particularly limited. However, the foundation lower end level required for the building 2 needs to be shallower than the lower end of the existing underground skeleton 11, and at least part of the building 2 is located within the range of the existing underground skeleton 11 on the plane.

In addition, the weight W1 of the building 2 including the reinforced floor 3, the weight W2 of the refilling material 13, and the weight W3 of the removed portion (the ground portion 12, etc.) of the existing skeleton 10 have the relationship of the following formula (1),
W3≧W1+W2 (1)
The supporting force S of the ground 41 under the foundation of the existing skeleton 10 has the relationship of the following formula (2) between the weights W1 and W2 and the weight W4 of the existing underground skeleton 11 that has not been removed.
S≧W1+W2+W4 (2)

In this embodiment, the inside of the wall 112 of the existing underground skeleton 11 is filled with the refilling material 13, the building 2 is provided on the upper surface of the refilling material 13, and then the reinforced floor 3 is constructed on the upper surface of the refilling material 13 between the building 2 and the wall 112. At this time, the foundation structure 1 is formed by connecting the building 2 and the upper part of the wall 112 of the existing underground skeleton 11 with the reinforcing floor 3 .

The wall 112 of the existing underground skeleton 11 must prevent the outflow of the refilling material 13 while resisting the lateral pressure from the inner refilling material 13 caused by the surcharge of the newly built building 2. The stress generated in the direction in which the

On the other hand, in this embodiment, as shown in FIG. 2B, the upper part of the wall 112 is connected to the building 2 by the reinforcing floor 3, so that the upper part of the wall 112 also becomes a fixed end, and the bending stress generated in the wall 112 is reduced by eliminating the state of the cantilever structure. In this embodiment, the bending stress does not exceed the short-term allowable stress of the wall 112 . The short-term allowable stress of the wall 112 is determined by the material, cross-sectional configuration, and the like of the wall 112 .

It is particularly effective to apply the foundation structure 1 of the present embodiment under conditions in which the lateral pressure from the ground 4 outside the existing underground skeleton 11 cannot be expected temporarily or for a long period of time. More specifically, the ground 4 that may liquefy is, for example, a soil layer shallower than about 20 m from the ground surface, such that the fine grain content is 35% or less below the groundwater level.

FIG. 3( a ) is a view showing joints between the reinforcing floor 3 and the walls 112 of the existing underground skeleton 11 . In this example, the upper part of the wall body 112 of the existing underground skeleton 11 has a structure in which earth pressure walls 1121 are provided above and below with an underground beam 1122 interposed therebetween.

Further, the reinforcing floor 3 has a configuration in which the beam-like portion 32 is integrated with the lower surface of the outer peripheral portion of the plate-like portion 31 . The beam-like portion 32 is provided horizontally so as to extend along the wall 112 in the plane. The extending direction of the beam-like portion 32 (and the wall body 112) in the plane corresponds to the normal direction of the page of FIG. 3(a).

The outer peripheral portion of the plate-like portion 31 reaches the wall body 112 , and the outer end portion of the plate-like portion 31 contacts the inner surface of the earth pressure wall 1121 . The beam-like portion 32 is placed on the inner peripheral portion of the underground beam 1122 and contacts the upper surface of the underground beam 1122 and the inner surface of the earth pressure wall 1121 . The portions of the soil pressure wall 1121 and the underground beams 1122 that come into contact with the plate-like portion 31 and the beam-like portion 32 are roughened to form unevenness.

The beam-shaped portion 32 provides a degree of fixation to the upper portion of the wall 112 and causes bending stress due to lateral pressure from the refilling material 13 to the upper portion of the wall 112 . As described above, the reinforced floor 3 is made of reinforced concrete, and reinforcing reinforcing bars R are arranged in the plate-shaped portion 31 and the beam-shaped portion 32. Some of the reinforcing bars R1 protrude from the soil pressure walls 1121 and the underground beams 1122 and are inserted into the beam-shaped portion 32, whereby the beam-shaped portion 32 is joined to the upper portion of the wall 112, and the bending stress of the upper portion of the wall 112 is transmitted to the reinforcing bars in the beam-shaped portion 32.

Another reinforcing bar R2 protrudes from the beam-shaped portion 32 and is inserted into the plate-shaped portion 31, whereby the beam-shaped portion 32 and the plate-shaped portion 31 are integrated. Therefore, the bending stress of the upper portion of the wall 112 is transmitted to the plate-like portion 31 through the beam-like portion 32, and the reinforcing floor 3 has a structure with high bearing strength. In addition, in the example of FIG. 3( a ), a reinforcing bar R<b>3 that protrudes from the soil pressure wall 1121 and is inserted into the plate-like portion 31 is also provided.

On the other hand, FIG. 3(b) shows an example of a joint between the reinforced floor 3 and the building 2. In this example, reinforcing bars R4 (joining material) protruding from the building 2 are arranged in the concrete of the reinforced floor 3, so that the building 2 and the reinforced floor 3 are integrated, and the connection state between the building 2 and the wall 112 of the existing underground skeleton 11 via the reinforced floor 3 can be ensured.

As described above, according to the present embodiment, when the inner side of the wall 112 of the existing underground skeleton 11 is filled with the backfill material 13 to serve as the supporting ground of the newly built building 2, the upper part of the wall 112 of the existing underground skeleton 11 is connected to the building 2 to ensure the degree of fixation of the upper part of the wall 112. As a result, the wall 112 of the existing underground skeleton 11 can be prevented from becoming a cantilever structure, and the stress generated in the wall 112 due to the lateral pressure from the inner refilling material 13 can be reduced.

In this embodiment, it is only necessary to reinforce the upper part of the wall 112 of the existing underground skeleton 11, so there is no need to excavate a large amount of backfill material 13, and it is possible to carry out construction from the ground while leaving the inside of the existing underground skeleton 11 as it is, which facilitates construction. As a result, it is possible to reduce the cost, labor, and construction period required for construction.

In addition, in this embodiment, by providing the reinforced floor 3 between the building 2 and the wall 112 as a connecting portion between the building 2 and the wall 112 of the existing underground skeleton 11, the reinforced floor 3 can be constructed after the building 2 is constructed.

The reinforced floor 3 has a beam-like portion 32 integrated with the lower surface of the outer peripheral portion of the plate-like portion 31. By joining the beam-like portion 32 to the upper portion of the wall 112 of the existing underground skeleton 11, the fixing degree of the upper portion of the wall 112 can be secured, and the bending stress of the upper portion of the wall 112 is transmitted not only to the beam-like portion 32 but also to the plate-like portion 31, resulting in a structure with high strength.

However, the invention is not limited to the above embodiments. For example, as described above, the present invention is particularly effective when applied under conditions where the lateral pressure from the ground 4 outside the existing underground skeleton 11 cannot be expected temporarily or for a long period of time. For example, the outside of the existing underground skeleton 11 may be a water area such as a river, or may be hollow temporarily or over a long period of time due to excavation or the like.

In addition, as shown in FIG. 4, a frame such as a beam 15, a column 16, and other walls may exist inside the existing underground skeleton 11. In any case, the inside of the existing underground skeleton 11 should be densely filled with the backfill material 13. In addition, the slab is basically removed in the existing underground skeleton 11 for filling.

The structure of the joint between the reinforcing floor 3 and the wall 112 of the existing underground skeleton 11 also differs depending on the shape of the wall 112, and is not limited to that described with reference to FIG. 3(a). For example, if the gap between the building 2 and the wall 112 is narrow, the beam-like portion 32 can be omitted and the plate-like portion 31 can be joined directly to the wall 112 . It is also possible to introduce prestress to the plate-like portion 31 and the beam-like portion 32 to improve the proof stress.

Further, in this embodiment, the building 2 and the wall 112 of the existing underground skeleton 11 are connected by the reinforcing floor 3 provided on part of the upper surface of the refilling material 13, but the connection method is not limited to this. For example, as shown in the basic structure 1a of FIG. 5, a reinforced floor 3a may be provided over the entire upper surface of the refilling material 13, and the building 2 may be newly constructed on the upper surface of the reinforced floor 3a. In this case, construction of the building 2 is facilitated.

The joints between the reinforcing floor 3a and the walls 112 of the existing underground skeleton 11 can be configured in the same manner as in FIG. 3(a). The building 2 and the reinforced floor 3a can be integrated by a joint material such as a shear reinforcing bar (not shown) arranged over the building 2 and the reinforced floor 3a.

In the present embodiment, as shown in FIG. 6(a), the newly built building 2 is contained within the range of the existing underground skeleton 11 on the plane, but as shown in FIGS. In either case, the space between the building 2 and the walls 112 of the existing underground skeleton 11 is entirely covered with the reinforcing floors 3, 3a. However, it is possible to intermittently provide the reinforcing floors 3 and 3a to create a gap between them.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope of the technical ideas disclosed in the present application, and these are naturally within the technical scope of the present invention.

1, 1a: Foundation structure 2: Building 3, 3a: Reinforced floor 4: Ground 11: Existing underground frame 13: Backfill material 31: Plate-like portion 32: Beam-like portion 111: Floor 112: Wall

Claims (6)

The inside of the wall of the existing underground skeleton having a floor and a wall on the outer periphery thereof is filled with a backfill material,
The refilling material is a material having fluidity,
A building foundation structure in which the building above the refilling material and the upper part of the wall are connected by a connecting portion,
The foundation structure of the building, wherein the surcharge load of the building is supported only by the supporting ground composed of the existing underground skeleton and the backfill material. The connecting part is a reinforced floor,
2. The foundation structure of a building according to claim 1 , wherein said reinforcing floor is composed only of a plate-like portion . The connecting part is a reinforced floor,
2. The building foundation structure according to claim 1, wherein the reinforcing floor has a plate-like portion and a beam-like member provided between the building and the wall and extending along the wall in a plane. The inside of the wall of the existing underground skeleton having a floor and a wall on the outer periphery thereof is filled with a backfill material,
The refilling material is a material having fluidity,
The building above the refilling material and the upper part of the wall are connected by a connecting portion,
The building is provided on the upper surface of the refilling material,
A reinforced floor, which is the connecting part, is provided between the building and the wall,
The reinforcing floor is formed by integrating a beam-shaped portion extending along the wall in a plane with the lower surface of the outer peripheral portion of the plate-shaped portion,
A foundation structure , wherein the beam-like portion is joined to an upper portion of the wall . The inside of the wall of the existing underground skeleton having a floor and a wall on the outer periphery thereof is filled with a backfill material,
The refilling material is a material having fluidity,
The building above the refilling material and the upper part of the wall are connected by a connecting portion,
A reinforcing floor that is the connecting portion is provided on the upper surface of the refilling material,
The building is provided on the upper surface of the reinforced floor,
The reinforcing floor is formed by integrating a beam-shaped portion extending along the wall in a plane with the lower surface of the outer peripheral portion of the plate-shaped portion,
A foundation structure , wherein the beam-like portion is joined to an upper portion of the wall . A method of constructing a foundation structure for connecting the building and the upper part of the wall with a connecting portion when constructing a building above the refilling material in a state where the inside of the wall of an existing underground skeleton having a floor and a wall on the outer periphery thereof is filled with a refilling material having fluidity,
A step of providing the building on the upper surface of the refilling material;
constructing the connecting part so as to connect the building and the upper part of the wall;
including
A method of constructing a foundation structure, wherein, in the foundation structure, an overburden load of the building is supported only by a supporting ground composed of the existing underground skeleton and the backfill material.

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