JP4217189B2 - Pile foundation structure for buildings - Google Patents

Description

  The present invention relates to a pile foundation structure for a building and a construction method thereof. More specifically, a pile foundation structure for a building having a foamed resin board exhibiting a desired range of compression set as a component of the pile foundation and capable of protecting the pile foundation structure and the building from vibration such as an earthquake, and It relates to the construction method.

Conventionally, the pile foundation which supports the load of a building with a support pile body, a pile head, etc. is employ | adopted as a foundation for buildings (for example, refer nonpatent literature 1). The said pile foundation has a pile head which couple | bonds with the support pile body which stood up in the perpendicular direction from this support layer, and this support pile body upper part by making the firm ground located in the perpendicular downward direction of a building into a support layer. In general, a relatively weak or soft surface layer of the ground surface (hereinafter also simply referred to as “soft layer”) exists between the building and the support layer. Here, as the soft layer, in addition to the layer that is soft as an original property of the ground, when the foundation is built in the hole formed to provide the pile foundation, the periphery of the pile foundation is backfilled Also included is a soft ground portion that is formed.
According to the said pile foundation, a building can be stably supported by transmitting a building load to a support layer. Therefore, in particular, it is employed as a foundation structure suitable for building a building on soft ground or for building a large building.

  By the way, when the pressure from the horizontal direction or the vertical direction is received due to the vibration of the earthquake, the soft layer located between the building supported by the pile foundation and the support layer is compressed and deformed to be a strong layer May be simply referred to as “compressed deformation layer”). In such a case, it is difficult to artificially restore the layer once compressed and strong to the original ground shape. Since pile foundations and buildings are constrained by the compression deformation of the soft layer, various problems occur. Various problems related to the conventional pile foundation will be described with reference to FIGS. 9 to 11.

FIG. 9 (9 A) shows a conventional pile foundation having a building 105 constructed above the support layer 107 and the soft layer 106, a support pile body 102, a pile head 103, and an underground beam 104. The lower end of the support pile 102 is connected to a strong support layer 107, and the upper end is connected to the building via the pile head 103 and the underground beam 104.
When vibration due to an earthquake occurs around the pile foundation, as shown in FIG. 9B, vertical pressure P is applied to the building 105, and the soft layer located below the building is compressed and deformed. The layer 108 is formed, and at the same time, the building 105 may sink by the amount of sinking. Further, the support pile body 102 whose upper and lower ends are constrained by the connection is subjected to a load due to the pressure P in the vertical direction, and as a result, there is a problem that the support pile body 102 is cracked or disconnected.
Further, after the generation of the pressure P in the vertical direction, further vibrations may occur to generate a pressure Q in a direction different from the pressure P in the vertical direction as shown in FIG. At this time, the building 105 is pushed up in the direction of the pressure Q. However, since the compression deformation layer 108 once compressed and deformed does not autonomously restore to the original ground shape, the bottom surface of the building 105 and the compression deformation layer 108 are separated from each other. A phenomenon is known in which separation occurs and a gap 109 is formed between the two. By forming the gap 109 below the building 105, there is a problem that the horizontal resistance and durability of the support pile 102 are greatly affected, and the building 105 may be inclined or toppled.
Another problem caused by the gap 109 is that the friction resistance between the building 105 and the ground is lost due to the fact that the building 105 and the compression deformation layer 108 are not in contact with each other, and a new vibration occurs after the gap 109 is formed. There is a problem that the shaking of the building 105 increases compared to before the formation of the gap 109.

  Aside from the above phenomenon, where vertical pressure is applied to the building, a horizontal force and bending moment are applied to the building using the pile foundation in the event of an earthquake, and a bending moment is also applied to some supporting pile bodies. It has been known. This phenomenon arises from the fact that the upper and lower ends of the support pile are constrained by the building and the support layer, and that the natural periods of the support layer, the soft layer, and the building are different. That is, the seismic vibration causes displacement between the stratum and between the strata and the building, and the support pile body is constrained by this, and a bending moment is applied to the building and some of the support pile bodies.

The above phenomenon and its problems will be described below with reference to FIG. FIG. 10 (10A) shows a conventional pile foundation and a building 105 constructed thereon as in FIG. 9 (9A).
It is known that when a vibration occurs due to an earthquake or the like, a horizontal force H and a bending moment M may be applied to the building 105 as shown in FIG. At this time, since the upper and lower ends of the support pile body 102 are constrained, the support pile body 102 located in the direction in which the horizontal force H and the bending moment M are applied exerts a pushing force S and a bending moment, A pulling force R acts on the support pile 102 located in the direction opposite to the above direction.
As a result, the building 105 is inclined and part of the building 105 is buried in the ground, whereby the soft layer is compressively deformed, and the compressive deformation layer 108 is formed. Moreover, there is a possibility that the support pile body 102 may be damaged without enduring the inclination of the building 105. The problem that it is difficult for the compressive deformation layer 108 to self-recover and that the gap 109 is formed by a new pressure in another direction is the same as the problem described in FIG.

Further, as shown in FIG. 11, the building 105 having a basement has the following problems in the event of an earthquake. That is, as shown in FIG. 11B, when the horizontal force H and the bending moment M are applied to the building 105, the building 105 is tilted and the support pile 102 is Depending on the position, pulling force R or pushing force S and bending moment are applied. In addition to this, the basement 110 is also tilted in the ground, the compressive deformation layer 108 is formed, and the ground and the outer surface of the basement 110 are separated to form a gap 109.
As a result, there is a problem that the location of the building 105 including the basement 110 becomes unstable and dangerous. Moreover, there is a possibility that the support pile body 102 may be damaged without enduring the inclination of the building 105. The problem that it is difficult for the compressive deformation layer 108 to self-recover and that the gap 109 is formed by a new pressure in another direction is the same as the problem described in FIG.

  When the problems described above occur, the safety of the building cannot be achieved and it is very dangerous. However, it is difficult to accurately predict the influence of the pressure in a specific direction generated by the vibration of the earthquake, the horizontal force due to the difference in natural period, and the bending moment when designing buildings and foundations. Furthermore, due to the above effects, it is difficult to accurately predict the amount of ground deformation and the resulting void volume.

  Therefore, when a pile foundation structure is adopted as the foundation of a building, it is desired to prevent or reduce the compressive deformation of the ground even if vibration such as an earthquake occurs, thereby preventing or reducing the generation of voids. It was. Also, in the event of an earthquake, due to differences in the natural period of the stratum and the building, it is possible to reduce the influence of the horizontal force on the building adopting the pile foundation and the bending moment on the building and some supporting pile bodies. It was desired.

The Architectural Institute of Japan, “Basic Design Guidelines for Architectural Foundations”, 1st Edition, 8th Edition, The Architectural Institute of Japan, July 25, 1996, p. 197-214

  This invention is made | formed in view of the problem of the said conventional pile foundation. That is, according to the present invention, even if vibration such as an earthquake occurs around a building using a pile foundation, a compressive deformation of the soft layer is prevented or reduced, and a gap is generated between the pile foundation structure or the building and the ground. Provided is a pile foundation structure that can reduce the horizontal force and bending moment applied to the building due to the difference in the natural period between the stratum and the building and the restraint of the upper and lower ends of the supporting pile body It is for the purpose. In addition, the present invention provides a pile foundation structure that can prevent a gap from being generated due to separation of a side surface of the basement and the ground even if vibration such as an earthquake occurs in a building having a basement. It is for the purpose.

  Another object of the present invention is to provide a method for easily constructing the pile foundation structure of the present invention.

The present invention
(1) A pile foundation structure for buildings comprising a pile support structure and a foamed resin board,
The above pile support structure consists of a support pile body, pile head and underground beam,
The foamed resin board has a compression set of 0.1% to 30%, and
Above the foam, so as to cover the upper part of the pile support structure that is below the building and includes at least the position in contact with the entire circumference of the pile head side surface and the ground and / or the position in contact with the entire bottom surface of the pile head and the ground. Pile foundation structure for buildings, characterized in that resin boards are arranged,
(2) The underground beam is provided around the pile head,
The foundation structure for building according to (1) above, wherein the foamed resin board is disposed between the entire surface of the underground beam side surface and the entire surface of the underground beam bottom surface, and the ground,
(3) A pile foundation structure for a building having a basement with a pile support structure and a foamed resin board, wherein the foamed resin board is interposed between the outer surface of the building basement and the ground. The pile foundation structure for buildings as set forth in (1) or (2) above,
Is a summary.

If it is the pile foundation structure for buildings of the present invention, it is the lower part of a building, and at least the position which touches a pile head side part perimeter and the ground, and / or the pile head bottom part whole surface and the ground Place a foamed resin board showing a desired range of compression set at a position covering the upper part of the pile support structure including the position, and the foamed resin board is in contact with a part of the pile support structure and the ground, so that vibration due to earthquakes, etc. Can protect the building and pile foundation structure. This prevents or reduces problems such as settlement of buildings, damage to support pile bodies, and adverse effects caused by voids formed in the ground that have occurred due to vibration in buildings using conventional pile foundation structures. Can do.

Specifically, according to the pile foundation structure of the present invention, even when a building is subsidenced or inclined due to the occurrence of vibrations, such as vertical pressure, horizontal force, and bending moment, etc. Prior to the layer, the foamed resin board in the present invention is compressed. At the same time, the foamed resin board can absorb pressure such as vertical direction, horizontal force and bending moment generated by the vibration. As a result, it is possible to prevent the soft layer from being compressed and the compression deformation layer from being formed, and to reduce the amount of settlement and inclination of the building. Moreover, the load concerning the support pile body by which the upper and lower ends are restrained can be reduced, and the breakage of the support pile body can be prevented.
Furthermore, by preventing or reducing the formation of the compressive deformation layer, even if a new pressure is generated in another direction, the ground and the building or the pile foundation structure part are separated to prevent the formation of a void. be able to.

  Since the foamed resin board in the present invention exhibits a desired range of compression set, even if it is compressed once, it can recover autonomously to a shape close to the original shape over time. Therefore, even if the foamed resin board is compressed and deformed due to the occurrence of vibration, it can be continuously used as a part of the component of the pile foundation structure.

  According to the present invention in which the foamed resin board is further interposed between the outer surface of the basement and the ground, in addition to the above effects, it is possible to prevent the formation of voids due to the separation of the side of the basement and the ground.

  If it is the construction method of this invention which builds the said pile foundation structure, at least one part of a pile support structure and a foamed resin board can be joined by simple construction. In addition, since the foamed resin board used in the present invention is inexpensive and can be mass-produced, it is possible to construct a pile foundation structure that is resistant to vibration at a low cost.

  In addition, the pile foundation structure of the present invention provided with the foamed resin board has a damping effect of seismic vibration. Therefore, since the vibration transmitted from the ground to the building is attenuated when passing through the pile foundation structure of the present invention, the seismic intensity in the building can be reduced. Therefore, according to the pile foundation structure of the present invention, very excellent seismic performance can be imparted to the building.

  The foamed resin board used in the present invention has no adverse effect on the natural environment even if it is buried in the ground. Therefore, the pile foundation structure of the present invention can be used with peace of mind even in a location environment where there is use of groundwater in the vicinity.

  The best mode for carrying out the present invention will be described below with reference to the drawings illustrating the present invention.

  1 to 3 show a pile foundation structure of the present invention including a pile support structure 8 including a foamed resin board 1, a support pile body 2, a pile head 3, and an underground beam 4, and a building constructed thereon. FIG. The pile foundation structure hits the support pile body 2 which is bonded to the support layer 7 through the soft layer 6 at a predetermined position, and then the foam resin board 1 is formed on the bottom surface of the hole formed by soiling the soft layer 6. It can be formed by arranging the pile head 3 and the underground beam 4. The foamed resin board 1 is in contact with the underground beam side face 18 and the pile head side face 14 and the soft layer 6 in the pile support structure 8. In this specification, GL means the ground level.

  FIG. 4 is a schematic vertical sectional view of the pile foundation structure A1 of the present invention. The pile foundation structure A1 includes a pile support structure 8 including a foamed resin board 1, a support pile body 2, a pile head 3 coupled to the upper portion of the support pile body 2, and an underground beam 4 provided around the pile head 3. It is formed in preparation. The foamed resin board 1 in the pile foundation structure A <b> 1 is in contact with the underground beam bottom surface portion 17, the underground beam side surface portion 18, the pile head bottom surface portion 14, and the soft layer 6 in the pile support structure 8.

  FIG. 5 is a schematic vertical sectional view of the pile foundation structure A2 of the present invention. The pile foundation structure A <b> 2 includes a pile support structure 8 including the foamed resin board 1, the support pile body 2, the pile head 3, and the underground beam 4. Moreover, between the several pile heads 3, the floor board 9 which is a part of building is provided in the horizontal direction, and also the 1st floor 11 is provided on it. Thus, a pit 13 surrounded by the first floor 11, the pile head 3, the underground beam 4 and the floor board 9 is formed. Furthermore, in order to prevent the foamed resin board 1 from being exposed to the ground surface, a concrete plate 12 is provided on the upper surface of the foamed resin board 1 located on the outer periphery of the pile foundation structure. The foamed resin board 1 in the pile foundation structure A <b> 2 is in contact with the pile head side face part 14 and a part of the underground beam side face part 18 in the pile support structure 8 and the ground which is the soft layer 6. Furthermore, the foamed resin board 1 is also in contact with the bottom surface of the floor board 9 which is a part of the structural part of the building. Note that the term pit used in the present specification means a space formed by being surrounded by each constituent member, for example, a space in which piping or the like is installed.

  FIG. 6 is a schematic horizontal sectional view taken along line VV of the pile foundation structure A2 of the present invention. A pile head 3 is formed around the cross-section of the support pile body 2 and both are coupled. Further, a foamed resin board 1 is arranged around the pile head 3, and the pile head side face 14, the foamed resin board 1, Is shown touching.

  FIG. 7 is a schematic vertical sectional view of the pile foundation structure A3 of the present invention. The pile foundation structure A3 can be formed in the same manner as the pile foundation structure A2 shown in FIG. 5 except that the pile head bottom surface portion 15 is in contact with the foamed resin board 1.

  FIG. 8 is a schematic vertical sectional view of the pile foundation structure A4 of the present invention. The pile foundation structure A4 is formed below the basement 10 in the hole formed in consideration of the dimensions of the basement 10 and the pile foundation structure A4, except that the foamed resin board 1 is disposed on the basement outer surface 16. 4 can be formed in the same manner as the pile foundation structure A1 shown in FIG. The term “basement” used in the present invention means a space in the ground formed with an independent bottom surface and side surfaces, such as a living space, a garage, or a warehouse. Therefore, it does not include the space formed as a result of being surrounded by other components such as pits.

The pile support structure in the present invention means a structure capable of supporting the total load of the building and transmitting the load to the support layer, and has at least a support pile body. Therefore, according to the present invention, the total load of the building is supported by the pile support structure and the support layer. As the pile support structure, any structure including a load support member of a generally known pile foundation can be used as appropriate. For example, the support pile body and the pile head, or the support pile body, the pile head, and the underground beam There is a pile support structure and so on.
The support pile used in the present invention may be of any type as long as it stands vertically from the support layer and its upper end is directly or indirectly connected to the building and transmits the load of the building to the support layer. Can be used. Specifically, there are driven piles that are driven into the ground using existing pile bodies, embedded piles that are provided with holes in the ground and embedded in existing pile bodies, or in-situ concrete piles such as all-casing piles or earth drill method piles, etc. However, it is not limited to the above.
Further, components other than the supporting pile body, for example, pile heads or underground beams, can be appropriately selected and used as long as they are generally known in conventional pile foundations.

  In addition, in the range which does not deviate from the meaning of this invention, it is possible to further add other structural members other than a pile support structure and a foamed resin board as needed, for example, a friction pile body.

  In particular, the pile foundation structure of the present invention having a pile support structure including a support pile body, a pile head, and an underground beam is formed in such a manner that the foamed resin board is in contact with the pile head and / or the underground beam and the ground. It is preferable. It is preferable that the foamed resin board is interposed between the pile head and / or the underground beam and the ground because vibrations and pressures generated by an earthquake are attenuated or absorbed by the foamed resin board.

The foamed resin board according to the present invention is a pile support which is below the building and includes at least a position in contact with the entire circumference of the pile head side surface and the ground and / or a position in contact with the entire bottom surface of the pile head and the ground. Although it is in contact with at least a part of the pile support structure and the ground by being disposed at a position covering the upper part of the structure, it does not exclude that other parts and the foamed resin board are in contact. Therefore, as shown in FIG. 5, it does not exclude that the structural portion of the pile support structure 8 in the soft layer 6, for example, the lower surface of the floor surface 9 and the foamed resin board 1 are in contact with each other.

  The foamed resin board used in the present invention has a compression set within the range of 0.1% to 30%, more preferably 0.1% to 25%, more preferably 0.1% More preferably, it is 20% or less. In addition, the compression set in the present invention can be measured according to JIS K 6767. Specifically, a test piece of 50 × 50 × about 25 mm in thickness is prepared from a foamed resin board, and pressure is applied to the test piece with a flat plate in a standard state at a temperature of 20 ± 2 ° C. and a relative humidity of 65 ± 5%. 25% of the initial thickness of the test piece is compressed, fixed as it is, and left for 1 minute, and then the flat plate is removed and left for 10 minutes in the above standard state. As a result, a compression permanent strain is defined as a percentage of the original thickness with respect to the strain amount of the test piece having a changed thickness. Therefore, the compression set in the present invention indicates the amount of strain due to an external force applied for a relatively short time.

In the present invention, by using a foamed resin board exhibiting compression set within the desired range, after the foamed resin board is compressed and deformed prior to the soft layer and absorbs external force, the external force is removed. It is important that it is restored autonomously to a size close to the original shape. Thereby, even if pressure is generated in the ground due to an earthquake, it is possible to avoid compressive deformation of the soft layer that is difficult to recover artificially. In addition, by the self-recovery of the foamed resin board, it can be continuously used as a constituent member of the pile foundation structure after being once compressed and deformed. When a displacement difference occurs between the building and the ground due to the occurrence of an earthquake, the foamed resin board compresses and absorbs the displacement difference, and then recovers to a shape close to that of the original foamed resin board. This is very important.
The recovery rate of the shape after compression deformation of the foamed resin board in the present invention is preferably 70% or more and 100% or less, and 80% or more and 100% with respect to the vertical or horizontal dimension of the foamed resin board before compression deformation. Or less, more preferably 90% or more and 100% or less.

  Next, the effect | action of this invention is demonstrated below using FIGS. 1-3.

When vibration due to an earthquake or the like is transmitted to the pile foundation structure and the building 5 shown in FIG. 1 (1A), a vertical pressure P may be generated as shown in FIG. 1 (1B). At this time, the foamed resin board 1 is compressed and deformed prior to the soft layer 6 and the pressure P is absorbed by the foamed resin board 1. As a result, the building 5 sinks by the amount of building sinking i, and the support pile body 2 is bent. On the other hand, the compressive deformation of the soft layer 6 does not occur at all or is a very small deformation. Next, as shown in FIG. 1C, the distortion of the foamed resin board 1 is restored autonomously with the passage of time, the shape is restored, and settlement of the building 5 is thereby eliminated, and the supporting pile body The second deflection is also eliminated.
Therefore, when the pile foundation structure of the present invention is employed as the foundation of a building, the problem that occurs in the building 105 employing the conventional pile foundation shown in FIG. 9 does not occur. That is, according to the pile foundation of the present invention, as shown in FIG. 9 (9B), the building 105 to which the vertical pressure P is applied sinks by the amount of building settlement and the supporting pile body 102 is damaged. The gap 109 is formed by applying the pressure Q in a direction different from the pressure P as shown in FIG. 9C. There is no problem.
Moreover, the foamed resin board 1 in the pile foundation structure of this invention also has the effect | action of absorbing pressure itself. Thus, the vertical pressure P is equally applied to the building 105 employing the conventional pile foundation shown in FIG. 9 (9B) and the building 5 employing the pile foundation structure of the present invention shown in FIG. 1 (1B). In such a case, the amount of settlement of buildings B and B has a relationship of A <B, and the amount of settlement of building 5 in which the pile foundation structure of the present invention is adopted is smaller than that of building 105.

Another operation of the present invention will be described with reference to FIG. FIG. 2 (2A) shows the pile foundation structure of the present invention and the building 5 constructed thereon as in FIG. 1 (1A). When vibration due to an earthquake or the like is transmitted to the pile foundation structure and the building 5, a horizontal force H and a bending moment M are applied to the building 5, and a bending moment may be applied to some supporting pile bodies 2. . At this time, the building 5 is inclined as shown in FIG. 2B, and a part of the building 5 is apparently buried in the soft layer 6. However, since the foamed resin board 1 substantially compresses and deforms prior to the soft layer 6, the soft layer 6 does not compress or deforms in a very small range. In addition, the foamed resin board 1 absorbs the horizontal force H and the bending moment M, and reduces the force that they give to the building 5 and the support pile body 2. As a result, the horizontal force H and the building 105 adopting the conventional pile foundation shown in FIG. 10 (10B) and the building 5 adopting the pile foundation structure of the present invention shown in FIG. When the bending moment M is applied, the inclination of the building 5 is smaller than the inclination of the building 105. Further, the support pile body 2 is deflected but not damaged.
Next, as shown in FIG. 2C with the passage of time, the distortion of the foamed resin board 1 is restored autonomously and its shape is restored, whereby the inclination of the building 5 is also eliminated, and the support pile 2 The flexure is also eliminated.
Therefore, when the pile foundation structure of this invention is employ | adopted as a foundation of a building, the problem which arises in the building 105 which employ | adopted the conventional pile foundation shown in FIG. 10 does not generate | occur | produce. That is, according to the pile foundation structure of the present invention, the pulling force R and the pushing force S are applied to the support pile body 102 constrained by the building 105 and the support layer 107, and the problem that the building 105 is greatly inclined, is supported at the same time. The problem that the pile body 102 is damaged and the problem that the compressive deformation layer 108 that cannot be restored independently are not generated.

Furthermore, the effect | action of this invention regarding the building which has a basement is demonstrated using FIG. 3 (3A) shows the pile foundation structure of the present invention in the building 5 having the basement 10. FIG. As shown in FIG. 3B, when a horizontal force H and a bending moment M are applied to the building 5, apparently a part of the building 5 is buried in the soft layer 6. At this time, the basement 10 is inclined. However, the foamed resin board 1 substantially compresses and deforms prior to the soft layer 6, and the soft layer 6 does not compress or deforms only very slightly. Accordingly, no gap is formed between the outer surface of the basement 10 and the ground. In addition, the foamed resin board 1 has an action of absorbing the horizontal force H and the bending moment M in the same manner as the action described above with reference to FIG. As a result, the inclination of the building in FIG. 3 (3B) is smaller than that of the building 105 in FIG. 11 (11B). Further, the support pile body 2 is deflected, but does not break.
Next, as shown in the figure (3C) with the passage of time, the distortion of the foamed resin board 1 is restored autonomously and its shape is restored, whereby the inclination of the building 5 is also eliminated, and the support pile 2 The flexure is also eliminated.
Therefore, when the pile foundation structure of the present invention is adopted as the foundation of a building, the problem that occurs in the building 105 employing the conventional pile foundation shown in FIG. 11 does not occur. That is, according to the pile foundation structure of the present invention, the pulling force R and the pushing force S are applied to the support pile body 102 constrained by the building 105 and the support layer 107, and the building 105 and the basement 110 are greatly inclined. The problem that the support pile body 102 is damaged at the same time, the problem that the compressive deformation layer 108 that cannot be restored autonomously is formed, and the problem that the gap 109 is formed between the outer surface of the basement 110 and the ground. Does not occur.

The structure of the present invention will be described in detail below. Foamed resin board used in the present invention is a building downward, at least, a position in contact with the pile head side portion all around the ground, and / or pile including a position in contact with the pile head bottom portion entirely and ground It is arrange | positioned in the position which covers the base support structure upper part , or also in the basement outer surface, and is contacting at least a part of pile support structure and the ground. The location of the foamed resin board can be appropriately determined in consideration of the load of the building, the structure, the location environment, the properties of the ground, and the like. By placing the foamed resin board exhibiting a desired range of compression set, the area protected by the foamed resin board increases as the contact area between the pile support structure and the building and the ground in the ground decreases. This is preferable.

For example, the foamed resin board in the present invention may be disposed on the entire surface of the pile head bottom surface portion 15, the underground beam bottom surface portion 17, and the underground beam side surface portion 18, as shown in FIG. At this time, the upper part of the support pile body 2 is also preferably covered with the foamed resin board 1, which is preferable. That is, since the upper part of the support pile body 2 is covered and protected by the foamed resin board 1, the joint part of the support pile body 2 and the pile head 3 can be protected. The length by which the upper part of the support pile body 2 is separated from the ground by the foamed resin board 1 can be appropriately determined in consideration of the shape of the pile support structure, the load of the building 5, the location environment, and the like. It is preferable that it is about 10 cm or more and about 100 cm or less from the coupling | bond part of the pile head 3 and the support pile body 2 to the downward direction.
Moreover, as shown in FIG. 5, the foamed resin board 1 may be arrange | positioned in the whole lower surface of the floor board 9 provided between the underground beam side part 18 whole surface and the various middle beams 3 (refer FIG. 6). In this embodiment, since the height of the bottom face of the foamed resin board 1 can be made uniform, the formation of the hole for placing the foamed resin board 1 and the placement work of the foamed resin board 1 are simple. In addition, the foamed resin board 1 itself can be a formwork of the pile head 3 if the foamed resin board 1 is arranged and then the concrete for forming the pile head 3 is placed in that order. Therefore, it is possible to simplify the construction process because it is possible to save the trouble of newly providing the formwork of the pile head 3. Further, the foamed resin board 1 is also disposed in the soft layer 6 other than the pile foundation structure, for example, between the floor board 9 and the soft layer 6, so that the structural part of the building 5 is also protected by the foamed resin board 1. This is preferable.
Furthermore, as shown in FIG. 8, in the building 5 having the basement 10, the foamed resin board 1 may be disposed on a part or the entire surface between the basement outer surface 16 and the ground. The larger the contact area between the basement outer surface 16 and the foamed resin board 1 is, the more preferable the protective effect of the foamed resin board 1 is.

  In addition, although the aspect of the arrangement | positioning location of a foamed resin board was demonstrated in the above, the arrangement of the foamed resin board in this invention is not limited to the above.

  Next, the foamed resin board used in the present invention will be further described. The thickness of the foamed resin board in the present invention is not particularly limited and can be appropriately determined depending on the scale of the building, the type of foundation, the nature of the ground, the location environment, etc. The preferred thickness is about 10 cm or more and about 150 cm or less. is there. Further, the thickness of the foamed resin board may be uniform or may be different in each place where the foamed resin board is disposed.

  Examples of the resin foam used for the foamed resin board include polystyrene resin foam, polyethylene resin foam, polypropylene resin foam, polyurethane resin foam, polyvinyl chloride resin foam, and thermoplastic polyester. Resin foam, polycarbonate resin foam, polyamide resin foam, polyphenylene ether resin foam, or a mixture of two or more of the above-described resins. In particular, a polystyrene resin foam, a polyethylene resin foam, a polypropylene resin foam, and a combination thereof are preferable from the viewpoint of weight and strength. Polyurethane resin foams may deteriorate in durability when hydrolysis occurs in the ground. Polyvinyl chloride resin foams generate hydrochloric acid gas when burned, causing pollution problems. Therefore, when using these resin foams, it is necessary to pay attention not to cause the above problem.

  Specific examples of the polystyrene resin foam, which is one of the above preferred resin foams, include styrene homopolymer resins, styrene copolymer resins produced from styrene and other monomers, and styrene alone. A rubber-modified styrene resin (impact resistant) obtained by polymerizing a styrene monomer in the presence of a polymer resin or / and a mixture of a styrene copolymer resin and a styrene-butadiene block copolymer or a rubber-like polymer. A polystyrene-based resin or a polystyrene-based resin composition having a styrene component ratio of 50% by weight or more, such as a mixture of a styrene-based resin) or a mixture of the above-described styrene-based resin with another resin or / and a rubber-like polymer. The resin foam formed in this way is included. If the said polystyrene-type resin foam is a foaming magnification about 50 times-about 120 times, since the compression set of the desired range in this invention is easy to be obtained, it is desirable.

  Specific examples of the polyethylene resin foam that is one of the preferred resin foams include ethylene homopolymer resins, ethylene copolymer resins produced from ethylene and other monomers, and ethylene alone A graft-modified ethylene resin obtained by impregnating a polymer resin or / and an ethylene copolymer resin with a vinyl monomer such as a styrene monomer and polymerizing, or the above-mentioned ethylene resin and another resin or / and rubbery heavy A resin foam formed by foaming a polyethylene resin or a polyethylene resin composition having an ethylene component ratio of 50% by weight or more, such as a mixture with a coalescence, is included. If the said polypropylene resin foam is a thing with a foaming magnification of about 30 times-70 times, since the compression set of the desired range in this invention is easy to be obtained, it is desirable.

  Specifically, a polypropylene resin foam, which is one of the preferred resin foams, includes a propylene homopolymer resin, a propylene copolymer resin produced from propylene and another monomer, and a propylene homopolymer. Graft modified propylene resin obtained by impregnating vinyl resin such as styrene monomer into polymer resin or / and propylene copolymer resin, or the above propylene resin and other resin or / and rubber-like polymer And a resin foam formed by foaming a polypropylene resin or a polypropylene resin composition having a propylene component ratio of 50% by weight or more. If the said polystyrene-type resin foam is a foaming magnification about 50 times-about 120 times, since the compression set of the desired range in this invention is easy to be obtained, it is desirable.

  The foamed resin board is formed as a foamed resin block of the desired shape by so-called in-mold foaming in which beads shaped foamed particles are filled in a container formed in a desired shape and heated to fuse the foamed particles together. can do. Alternatively, a desired shape can be obtained by filling spherical foamed particles in a suitably shaped container and heating them to fuse the foamed particles together to form a suitably shaped foamed resin block and then processing it into the desired shape. It can be formed as a foamed resin block of the shape.

The foamed resin board used in the present invention preferably has a compression creep of 10% or more, and more preferably 15% or more. If the compression creep of the foamed resin board is 10% or more, when external force is applied to the pile foundation structure and the building due to the occurrence of vibration due to an earthquake or the like, it is preferable to exhibit compression deformation well before the soft layer.
The compression creep of the foamed resin board can be measured based on JIS K 6767. Specifically, a test of 50 × 50 × thickness of about 25 mm was prepared using a foamed resin body forming a foamed resin board, and the test piece was in a standard state at a temperature of 20 ± 2 ° C. and a relative humidity of 65 ± 5%. When the thickness of the test piece when a load of ² g / cm ² is applied to is T ₀ , the test piece is allowed to stand with the above load applied, and the thickness after 168 hours is defined as T _d (T ₀ −T _d ) ÷ T ₀ × 100

Compressive strength of the foamed resin board used in the present invention is not particularly limited, it is preferably, about 10KN / ^{m 2} or more to about 50 KN / ^{m 2} or less than about 3 kN / ^{m 2} or more to about 100KN / ^{m 2} Is more preferable. If the compressive strength is about 3 KN / m ² or more, it is preferable because sufficient strength and good vibration absorption can be obtained as one component part of the pile foundation structure, and if it is about 100 KN / m ² or less, This is preferable because a compression set within a desired range in the present invention is easily obtained. In the pile foundation structure of the present invention, the total load of the building is supported by the pile support structure, and the load to be supported by the foamed resin board is not dispersed. Therefore, it is not necessary to obtain a high compressive strength for the foamed resin board, but it is desirable to adjust the compressive strength to such an extent that a preferable compression set can be obtained.

  In addition, the compressive strength of the said foamed resin board can be measured using the measuring method of the short-term compressive strength shown by JISK7220.

As an embodiment of the foamed resin board having compression set within the desired range, a foamed resin board having pores can be used. The above holes are grooves and holes provided as the outer shape of the foamed resin board, voids formed between the foamed resin beads constituting the foamed resin board, or spaces provided in beads of a specific shape. means. As an example of a method for forming a foamed resin board having holes, a groove mold or a hole mold having a desired shape is provided in advance in a mold for filling foam beads, and the foam resin beads are filled therewith. A foam having grooves or holes on the outer surface or a foam having holes penetrating the side surfaces can be formed. As another method, a foamed resin bead having a specific shape such as a chip shape or a cylindrical shape may be formed in advance, and foamed in the mold using the foamed resin bead having the specific shape. However, it is not limited to the said formation method.
The above-mentioned foamed resin board provided with holes may be covered with a water-permeable sheet so that earth and sand do not enter the holes. As the water-permeable sheet, a woven fabric, a non-woven fabric, a synthetic resin mesh sheet or the like having a pore diameter through which soil, sand, gravel, etc. in the ground cannot pass can be used. A resin nonwoven fabric is preferable, and a polypropylene or polyester nonwoven fabric is particularly preferable.

The porosity of the foamed resin board in the present invention means the volume% of pores provided on the side or inside of the foamed resin board with respect to the entire volume of the foamed resin board. The porosity can be determined by taking into account the desired compression set, compression creep, compression strength and the like of the foamed resin board. The porosity of the foamed resin board is not particularly limited, but is preferably about 10% to about 50%, more preferably about 20% to about 40%.
The porosity can be measured from the volume difference of a foamed resin board that apparently has the same volume and does not have pores and a foamed resin board that has pores. In the case of a foamed resin board having no pores and a foamed resin board having pores at a preferred rate, when the compressive strength is equal, the foamed resin body having pores at a generally preferred rate has a compression set. There is a tendency to be small. That is, it is preferable to use a foamed resin board having a porosity in the above preferred range for the present invention in that the self-recovering dimension after compression deformation is good.

  Next, the construction method of the pile foundation structure of this invention is demonstrated.

(1) Analyzing the earthquake characteristics of the ground in the building, the planned construction site of the building, vibration data of traffic, etc., determining the load bearing capacity etc. that the support pile structure should support, and configuring the support pile structure Determine the number, shape and dimensions of each member. The support pile structure requires at least a support pile body, and is generally composed of a pile head coupled to the upper portion of the support pile body, and an underground beam coupled to the pile head. However, it is not limited to these.
On the other hand, with respect to the foamed resin board, a preferable range of compression set, compression creep, compressive strength and the like are determined in consideration of ground characteristics and the like, and a foamed resin board satisfying them is formed. The foamed resin board in the present invention is used to compress and deform the soft layer prior to the occurrence of vibration due to an earthquake and to absorb the pressure generated by the vibration, and does not support the load of the building. . Therefore, when designing the load bearing capacity of the pile foundation structure, it is possible to design the foam resin board so as to support the entire load of the building without the burden of the load bearing capacity of the building on the foamed resin board. is important.

(2) The support pile body is driven at a predetermined position, and the tip of the support pile body is embedded in the support layer. The length at which the tip of the support pile is embedded in the support layer can be determined appropriately according to the load of the building, but in general, it is a portion of about 1 m to 3 m from the bottom tip of the support pile. Is preferably embedded in the support layer.
After embedding the support pile body, a hole for embedding the foamed resin board 1 is formed by removing the ground of the soft layer in a predetermined range. The shape of the hole can be appropriately determined depending on the shape of the foamed resin board, the presence or absence of the basement, and the like.

(3) Next, a foamed resin board is formed on the bottom surface of the hole. The foamed resin board can be appropriately arranged in accordance with the shape of the pile support structure. For example, when constructing the pile foundation structure A2 shown in FIG. 5, the foamed resin board 1 can be disposed while securing the space of the pile head 3 on the bottom surface of the hole. When the pile foundation structure A3 shown in FIG. 7 is formed, the foamed resin board 1 is arranged on the entire periphery of the support pile body 2 on the bottom surface of the hole, and the height of the foamed resin board 1 is adjusted. Thus, the space of the pile head 3 can be secured and arranged.
In order to form a foamed resin board, a plurality of foamed resin blocks having arbitrary dimensions and shapes can be combined or stacked. The foamed resin board may be formed by simply combining or stacking the plurality of foamed resin blocks in a hole formed to embed the foamed resin board. Alternatively, each foamed resin block may be bonded with an arbitrary adhesive or adhesive tape, or a foamed resin board may be formed by joining the foamed resin blocks using a fixture such as a bolt or a fastening metal fitting. .

(4) After forming the foamed resin board, a member that forms a pile support structure other than the support pile body is formed. When a space necessary for forming these members is secured by being surrounded by a foamed resin board, the foamed resin board may be used as a mold. For example, when the pile head 3 shown in FIG. 5 is formed, the space of the pile head 3 formed by the foamed resin board 1 and the ground can be used as a part of the form for forming the pile head 3.
When the pile support structure is formed, the pile support structure is formed so as to be in contact with the foamed resin board. In this invention, the upper part of a pile support structure is an area | region embed | buried in the soft ground of a pile support structure, Comprising: The part nearer to a building is pointed out. For example, if it is a pile support structure which consists of a support pile body, a pile head, and an underground beam, it will be set as the upper part of this pile support structure including the connection part of a pile head, an underground beam, and a support pile body and a pile head.

  (5) Next, the remaining space of the hole is refilled. Thereby, the pile foundation structure of the present invention is completed. Further, following the above process, a structural part of the building in the ground such as a floor board or a soil may be formed, and then a first floor may be formed, thereby forming a space generally called a pit. Moreover, in order to prevent the upper surface of the foamed resin board from being exposed to the ground surface, a concrete board can be formed together on the upper surface of the foamed resin board disposed near the ground surface.

  The construction method of the present invention is not limited to the above order. For example, after embedding a part of the foamed resin board and then constructing the pile head, the remaining part of the foamed resin board is buried, and finally the hole part Changes such as backfilling the remaining portion can be made as appropriate.

  Moreover, when building the pile foundation structure of this invention used for the building provided with a basement, a pile support structure and a foamed resin board are designed like (1) in consideration of a basement. Next, except for forming a hole in consideration of the basement, a pile support structure is embedded in the same manner as in (2) to (4) above, a foamed resin board is formed, and a pile support structure portion other than the support pile body Can be formed. Furthermore, a basement floor surface and a basement side surface are constructed, a foamed resin board is disposed along the basement side surface, and the remaining portion of the hole is refilled. Thereby, the pile foundation structure for buildings provided with the basement of this invention is completed.

Explanatory drawing for demonstrating the effect | action of the pile foundation structure of this invention Explanatory drawing for demonstrating the effect | action of the pile foundation structure of this invention Explanatory drawing for demonstrating the effect | action of the pile foundation structure of this invention Schematic diagram of a vertical cross section of an embodiment of a pile foundation structure of the present invention Schematic diagram of a vertical cross section of an embodiment of a pile foundation structure of the present invention Horizontal cross-sectional schematic of the VV line of the pile foundation structure shown in FIG. Schematic diagram of a vertical cross section of an embodiment of a pile foundation structure of the present invention Schematic diagram of a vertical cross section of an embodiment of a pile foundation structure of the present invention Explanatory drawing explaining the problem of the conventional pile foundation Explanatory drawing explaining the problem of the conventional pile foundation Explanatory drawing explaining the problem of the conventional pile foundation

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Foam resin board 2 Support pile body 3 Pile head 4 Underground beam 5 Building 6 Soft layer 7 Support layer 8 Pile support structure B Building subsidence amount B Building subsidence amount M Bending moment H Horizontal force P Vertical pressure Q Vertical pressure P Reverse pressure R Pull-out force S Push-in force

Claims (3)

A pile foundation structure for buildings comprising a pile support structure and a foamed resin board,
The above pile support structure consists of a support pile body, pile head and underground beam,
The foamed resin board has a compression set of 0.1% to 30%, and
Above the foam, so as to cover the upper part of the pile support structure that is below the building and includes at least the position in contact with the entire circumference of the pile head side surface and the ground and / or the position in contact with the entire bottom surface of the pile head and the ground. Pile foundation structure for buildings, characterized in that resin boards are arranged. The underground beam is provided around the pile head,
The building foundation structure according to claim 1, wherein the foamed resin board is disposed between the entire surface of the side surface of the underground beam, the entire surface of the bottom surface of the underground beam, and the ground. A pile foundation structure for a building having a basement with a pile support structure and a foamed resin board, wherein the foamed resin board is interposed between the outer surface of the building basement and the ground. The pile foundation structure for buildings according to claim 1 or 2 .

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