JP3202558U - Support structure for building foundation - Google Patents

Abstract

The present invention provides a support structure for a building foundation that can prevent re-sinking of a building by supporting the load of the building in a distributed manner using a support pile and a pressure plate. A building foundation support structure 1 extends from a work space B provided under the building foundation to a support layer, is laid on the bottom surface of the work space B, and has a pressure-resistant structure having an insertion hole in the center. The plate 20 is connected to the pressure plate 20 in a state of being inserted into the insertion hole, and the steel pipe pile 10 whose tip is located in the support layer is formed from the peripheral surface of the steel tube pile 10 to the upper surface of the pressure plate 20. A plurality of reinforcing ribs 30, a support base 40 interposed between the head of the steel pipe pile 10 and the bottom of the foundation A, and a backfill material 50 filling the inside of the work space B; The load of the building is distributed and supported by the steel pipe pile 10 and the pressure plate 20. [Selection] Figure 1

Description

  The present invention relates to a support structure for a building foundation, and more particularly to a support structure for a building foundation that prevents re-sinking of the building by supporting the building load in a distributed manner by support piles and pressure plates.

In buildings on soft ground, uneven settlement may occur where the site sinks unevenly and tilts the building.
To repair an unsettled building, jack up the sinking foundation and bring the tilted building back to level. These settlement settlement methods include various methods such as an underpinning method, a pressure plate method, and a point jack method.

Of these, the underpinning method is a method in which a work space is excavated under the foundation, a steel pipe pile is pressed into the support layer with a hydraulic jack using the building as a reaction force, and the foundation is jacked up using this as a support pile.
After jacking up, a spacer is inserted between the head and foundation of the steel pipe pile, and the building load is supported mainly by the tip support force and the peripheral frictional force acting upward at the tip of the steel pipe pile.
The pressure plate method is a method of jacking up the foundation by taking a reaction force from the pressure plate laid under the foundation.

The prior art described above has the following drawbacks.
<1> The underpinning method supports the load of the building only by support piles. For this reason, when the intermediate layer (relatively thin and shallow stratum) is used as the support layer, the tip of the support pile may penetrate the intermediate layer due to the concentration of load, and the building may be re-settled.
<2> In order to avoid this, the steel pipe pile needs to reach a deeper support layer. Therefore, the pile length becomes long, and the material cost and the construction cost increase.
In the <3> pressure plate method, if the ground is not sufficiently compacted, the ground may be consolidated by jacking up the reaction plate against the pressure plate, and the building may sink again.

  The support structure of the building foundation of the present invention for solving the above problems extends from the work space provided under the building foundation to the support layer and is laid on the bottom surface of the work space. A pressure plate having an insertion hole, and a pressure plate connected to the pressure plate in a state of being inserted into the insertion hole, and a steel pipe pile whose tip is located in the support layer, and from the circumferential surface of the steel pipe pile to the upper surface of the pressure plate A plurality of reinforcing ribs formed, a support base interposed between the top of the steel pipe pile and the bottom of the foundation, and a backfill material filling the interior of the work space, The load of the building is distributed and supported by the pressure plate.

  In the building foundation support structure of the present invention, it is desirable that the pressure plate is a rectangular plate and that four reinforcing ribs are provided along the diagonal line of the pressure plate.

  As for the support structure of the building foundation of this invention, it is desirable that a support layer is an intermediate | middle layer.

  As for the support structure of the building foundation of this invention, it is desirable for a steel pipe pile to connect a some short steel pipe.

  As for the support structure of the building foundation of this invention, it is desirable to have an improved soil layer under a pressure-resistant plate.

  In the building foundation support structure of the present invention, it is desirable that the support base has an upper plate and a bottom plate that are parallel to each other, and that the interval between the upper plate and the bottom plate can be fixed.

Since the building foundation support structure of the present invention has the above-described configuration, it has at least one of the following effects.
<1> Since the structure supports the building load in a distributed manner by the tip support force, peripheral friction force by the support pile, and the reaction force by the pressure plate, the building load is sufficient even in the middle layer, which is relatively thin Can be supported. Therefore, re-sinking of the building can be prevented.
<2> The pile length can be shortened by using the intermediate layer as a support layer. Therefore, material cost and construction cost can be greatly reduced as compared with the conventional method.
<3> An improvement layer is formed under the pressure plate, the ground under the improvement layer is sufficiently compacted, and both the steel pipe pile and the pressure plate are connected, so the pressure plate sinks after construction. Without fully supporting the building.
<4> Since the building load is distributed to the support pile and the pressure plate, jack-up is facilitated.

Explanatory drawing of the support structure of the building foundation which concerns on this invention. Explanatory drawing of a support stand. Explanatory drawing (1) of the construction method of the support structure of the building foundation which concerns on this invention. Explanatory drawing (2) of the construction method of the support structure of the building foundation which concerns on this invention. Explanatory drawing (3) of the construction method of the support structure of the building foundation which concerns on this invention. Explanatory drawing (4) of the construction method of the support structure of the building foundation which concerns on this invention. Explanatory drawing (5) of the construction method of the support structure of the building foundation which concerns on this invention. Explanatory drawing (6) of the construction method of the support structure of the building foundation which concerns on this invention. Explanatory drawing (7) of the construction method of the support structure of the building foundation which concerns on this invention. Explanatory drawing (8) of the construction method of the support structure of the building foundation which concerns on this invention. Explanatory drawing (9) of the construction method of the support structure of the building foundation which concerns on this invention.

  The building foundation support structure of the present invention will be described in detail below with reference to the drawings.

[Support structure of building foundation]
<1> Overall configuration (FIG. 1).
The support structure 1 for a building foundation according to the present invention is a structure constructed by a subsidence restoration work for a building that has subsided, and is a support structure having a function of preventing a subsidence of a building.
The building foundation support structure 1 of the present invention is a support structure constructed from the work space B under the foundation A to the support layer of the ground, and includes a steel pipe pile 10 that reaches the support layer from the work space B, and a steel pipe. The pressure plate 20 disposed on the bottom surface of the work space B with the insertion hole 21 inserted through the pile 10 and a plurality of reinforcements welded from the peripheral surface of the steel pipe pile 10 to the top surface of the pressure plate 20 and connecting the two. At least a rib 30, a support base 40 interposed between the head of the steel pipe pile 10 and the bottom surface of the foundation A, and a backfill material 50 filled in the work space B are provided.
In addition, although this example demonstrates the foundation A as a cloth foundation, it is applicable also to a solid foundation.

<2> Steel pipe pile.
The steel pipe pile 10 is a support pile that supports the load of the building by the tip support force and the peripheral friction force.
Each steel pipe pile 10 is a short steel pipe having a pile length of about 1 m, and this is continuously transferred into the ground to form a long support pile.
The steel pipe piles 10 are connected to each other by welding or other known means.
The uppermost steel pipe pile 10 is integrally connected to a pressure plate 20 described later. A reinforcing rib 30 is provided between the peripheral surface of the steel pipe pile 10 and the upper surface of the pressure plate 20.

<3> Pressure-resistant plate.
The pressure plate 20 is a face material that supports the load of the building by the support pressure to the ground.
In this example, a rectangular iron plate is used as the pressure plate 20. For example, a laid iron plate having a thickness t = 16 mm and about 600 mm × 600 mm can be employed.
A circular insertion hole 21 for inserting the steel pipe pile 10 is provided in the central portion of the pressure plate 20. The inner diameter of the insertion hole 21 corresponds to the outer diameter of the steel pipe pile 10.

<4> Reinforcing ribs.
The reinforcing rib 30 is a reinforcing member that reinforces the joint portion between the steel pipe pile 10 and the pressure plate 20 and prevents deformation of the pressure plate 20.
The reinforcing rib 30 is formed by welding a steel material from the outer periphery of the uppermost steel pipe pile 10 to the upper surface of the pressure plate 20.
In this example, four triangular reinforcing ribs 30 are provided along the diagonal line of the pressure-resistant plate 20. However, the shape and number of the reinforcing ribs 30 are not limited to this.
When the steel pipe pile 10 is pushed into the ground by the load of the building, the joint portion with the steel pipe pile 10 is drawn downward, and the pressure plate 20 may be deformed.
By providing the reinforcing rib 30 on the upper surface of the pressure plate 20, such deformation of the pressure plate 20 can be prevented.

<5> Support base (FIG. 2).
The support base 40 is a member that is interposed between the head of the steel pipe pile 10 and the bottom surface of the foundation A and transmits the building load to the steel pipe pile 10.
The support base 40 in this example has a function of maintaining the height adjusted by the hydraulic jack J.
That is, the support base 40 of this example includes an upper plate 41 and a bottom plate 42 provided in parallel, four cylindrical columns 43 projecting from the four corners of the bottom plate 42 toward the upper plate 41, and an upper plate 41. 4 bolt bars 44 projecting from the four corners toward the pillars 43 and capable of being inserted into the pillars 43, and four nuts 45 capable of being screwed to the bolt bars 44.
A cap that covers the head of the steel pipe pile 10 may be provided at the lower portion of the support base 40.
In a state where each bolt bar 44 is inserted into the column 43, the gap between the upper plate 41 and the bottom plate 42 is fixed by tightening the nut 45 to the mouth edge of the column 43. Thereby, the space | interval (height of the support stand 40) of the upper board 41 and the lower board 42 can be hold | maintained.
The structure of the support base 40 is not limited to this. For example, jacking up may be performed using a screw jack, and the screw jack after jacking up may be used as the support base 40 as it is.
Alternatively, a spacer such as a steel pipe may be interposed between the head of the steel pipe pile 10 after jacking up and the bottom surface of the foundation A, and this may be used as the support base 40.
In short, it is only necessary to maintain the jacked-up height and to have a function of transmitting the building load to the steel pipe pile 10.

<6> Backfill material.
The backfill material 50 is a material that fills the work space B.
Various types of improved soil can be used for the backfill material 50.

<7> Reason why the intermediate layer can be supported.
Since the conventional technology has a structure in which the load of the building is supported only by the support pile, if the intermediate layer is used as the support layer, the tip of the support pile may penetrate the intermediate layer due to the load of the building, causing re-settlement of the building. there were.
On the other hand, the building foundation support structure 1 according to the present invention is a structure in which the load of the building is distributed and supported by both the steel pipe pile 10 and the pressure plate 20 which are support piles.
That is, if the building load is P, [P = (steel pipe pile ≦ P) + (pressure plate ≦ P)], and the load is not concentrated on the steel pipe pile 10.
Therefore, the building load can be stably supported even if the intermediate layer is used as the support layer.
Moreover, the pile length of the steel pipe pile 10 can be shortened by making a comparatively shallow intermediate | middle layer into a support layer, and reduction of material cost and shortening of a construction period can be achieved by extension, and also construction cost can be reduced significantly.

[Construction method]
Next, the construction method of the support structure of the building foundation of this invention is demonstrated in detail, referring drawings.
In this construction method, multiple jack-up points are selected under the foundation of a building that has been subsidized, and the building foundation support structure of the present invention is provided at each jack-up point to jack up the foundation. It is a construction method to return to.
The jack-up point is selected according to the size and inclination of the building and the layout of the foundation. Since the selection method is a well-known technique, it will not be described in detail here.

<1> Formation of work space (FIG. 3A).
Excavate the ground directly below the foundation A of the building to form a working space B.
The size of the work space B is appropriate. For example, the work space B may be excavated so as to form a space of about width: depth: depth = 1 m × 1 m × 1.5 m under the foundation.
The bottom of the work space B is laid flat and leveled.

<2> Press fitting of steel pipe piles (FIG. 3B).
First, the steel pipe pile 10 (short steel pipe) is stood on the floor surface immediately below the foundation A, and the hydraulic jack J is interposed between the head of the steel pipe pile 10 and the bottom surface of the foundation A.
Subsequently, the reaction force is applied to the bottom surface of the foundation A, and the steel pipe pile 10 is press-fitted into the ground with the hydraulic jack J.
The tip of the subsequent steel pipe pile 10 is welded to the head of the steel pipe pile 10 that has been press-fitted in advance, and is similarly press-fitted into the ground.
As described above, the press-fitting with the hydraulic jack J and the welding of the steel pipe pile 10 are repeated, and the steel pipe pile 10 is handed over until reaching a support layer where a sufficient support force can be obtained.

<3> Ground cutting with steel pipe piles.
When the tip of the steel pipe pile 10 at the deepest part reaches the support layer, the sum of the tip support force and the peripheral friction force of the steel pipe pile 10 exceeds the building load, and the foundation A and the ground are cut by driving the hydraulic jack J. The
When the ground cut of about 1 to 2 cm is confirmed, the hydraulic jack J is released and removed from the head of the steel pipe pile 10.

<4> Improvement of the bottom surface of the work space (FIG. 3C).
A cement-based solidifying material is placed on the bottom surface of the working space B and leveled horizontally to form an improved layer. However, the method of forming the improved layer is not limited to this, and other known techniques such as spreading and improving the improved soil may be used.
The reason why the bottom surface of the work space B is improved after the steel pipe pile 10 is press-fitted is that if the bottom surface is improved in advance, the steel pipe pile 10 cannot be press-fitted due to the hardened ground.

<5> Laying the pressure plate (FIG. 3D).
The pressure-resistant plate 20 is installed on the bottom surface of the work space B by inserting the insertion hole 21 of the pressure-resistant plate 20 through the head of the uppermost steel pipe pile 10.

<6> Ground cutting with a pressure plate (FIG. 3E).
Hydraulic jacks J are installed on both sides of the steel pipe pile 10 on the pressure plate 20, and are operated between the pressure plate 20 and the foundation A, and the same reaction force as that when the steel pipe pile 10 is press-fitted is applied.
When the distance between the pressure-resistant plate 20 and the foundation A is larger than the maximum height of the hydraulic jack J, the height is appropriately adjusted by interposing the piece material K between the hydraulic jack J and the foundation A. For fine adjustment, the spacer S may be sandwiched between the top material K and the foundation A.
By driving the hydraulic jack J, the pressure-resistant plate 20 is pushed down with the base A as a reaction force, and the ground on the bottom surface of the work space B is tightly compacted.
When the ground is sufficiently compacted, the foundation A is pushed up with the pressure plate 20 as a reaction force, and the ground is cut from the ground. At this point, the hydraulic jack J is removed from the pressure plate 20.

<7> Connection between steel pipe pile and pressure plate (FIG. 3F).
The joint part of the steel pipe pile 10 and the pressure-resistant plate 20 is welded, and both are connected integrally.
Further, the reinforcing rib 30 is welded between the peripheral surface of the steel pipe pile 10 and the upper surface of the pressure plate 20. In this example, four reinforcing ribs 30 are provided on the diagonal line of the pressure-resistant plate 20.
The reinforcing rib 30 can reinforce the joint between the steel pipe pile 10 and the pressure plate 20 and can prevent deformation of the pressure plate 20 due to the steel pipe pile 10 being pulled.
Further, since the steel pipe pile 10 and the pressure plate 20 are integrally coupled by the reinforcing rib 30, the building load applied to the head of the steel pipe pile 10 is converted into the tip support force, peripheral friction force, and pressure resistance by the steel pipe pile 10. The reaction force by the plate 20 can be dispersed.
Therefore, even if a relatively shallow intermediate layer is used as a support layer, the building load can be sufficiently supported, and re-sinking of the building can be prevented.

<8> Installation of support base (FIG. 3G).
The support base 40 is placed on the head of the steel pipe pile 10.
The upper plate 41 of the support base 40 is lifted, and the hydraulic jack J is interposed between the upper plate 41 and the bottom plate 42.

<9> Preparation for jack-up.
The above operations <1> to <8> are performed at all jackup points.

<10> Horizontal adjustment of the building (FIG. 3H).
The foundation A is jacked up in order from the jack-up point where the subsidence amount of the foundation A is the largest, and the building is leveled. Specifically, the following work is performed at each jack-up point.
The hydraulic jack J is driven, the upper plate 41 of the support base 40 is brought into contact with the bottom surface of the foundation A, and the foundation A is pushed up through the upper plate 41.
When the foundation A is pushed up to a predetermined height, the drive of the hydraulic jack J is stopped, and the nuts 45 of the four bolt bars 44 of the support base 40 are rotated and lowered, and firmly tightened to the rim of the column 43. As a result, the distance between the top plate 41 and the bottom plate 42 is fixed.
Subsequently, the pressure of the hydraulic jack J is released and removed from the support base 40.
Since the support base 40 is fixed to the height after jack-up of the foundation A, the load of the foundation A can be transmitted to the steel pipe pile 10.
At each jackup point, jack up Foundation A to the appropriate height to level the building.
Since the load of the building is distributed to the steel pipe pile 10 and the pressure plate 20, the present invention can be easily jacked up as compared with the prior art.

<11> Backfill of work space (FIG. 3I).
The work space B at each jack-up point is filled with the backfill material 50, and the work space B is refilled.

DESCRIPTION OF SYMBOLS 1 Support structure of a building foundation 10 Steel pipe pile 20 Pressure-resistant plate 21 Insertion hole 30 Reinforcement rib 40 Support base 41 Top plate 42 Bottom plate 43 Post 44 Bolt bar 45 Nut 50 Backfill material A Foundation B Work space J Hydraulic jack K Top material S Spacer

Claims (6)

A support structure for a building foundation extending from a work space provided under the foundation of the building to a support layer,
A pressure-resistant plate laid on the bottom surface of the work space, and having an insertion hole in the center;
Steel pipe piles that are connected to the pressure plate in a state of being inserted through the insertion holes, and whose tips are located in the support layer,
A plurality of reinforcing ribs formed from the peripheral surface of the steel pipe pile to the upper surface of the pressure plate,
A support base interposed between the top of the steel pipe pile and the bottom of the foundation;
A backfill material filling the interior of the work space,
The steel pipe pile and the pressure-resistant plate support the load of the building in a distributed manner,
Support structure for building foundation.   2. The building foundation support structure according to claim 1, wherein the pressure plate is a rectangular plate member, and four reinforcing ribs are provided along a diagonal line of the pressure plate.   The building foundation support structure according to claim 1, wherein the support layer is an intermediate layer.   The building foundation support structure according to any one of claims 1 to 3, wherein the steel pipe pile is formed by connecting a plurality of short steel pipes.   The building foundation support structure according to any one of claims 1 to 4, further comprising an improved soil layer under the pressure plate.   The building according to any one of claims 1 to 5, wherein the support base includes an upper plate and a bottom plate that are parallel to each other, and is capable of fixing a distance between the upper plate and the bottom plate. Foundation support structure.

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