JP6048954B2 - Foundation structure and foundation construction method - Google Patents

Description

  The present invention relates to a foundation structure and a foundation construction method, and in particular, a foundation structure including a foundation main body connected to an upper structure of a building, and a pile body provided to extend in a lower ground, and the foundation structure It relates to the construction method of the foundation related to.

  Conventionally, as a foundation of a relatively small detached house as a building, a direct foundation placed directly on the ground such as a solid foundation, a cloth foundation, and an independent foundation has been generally used. In the case of such a direct foundation, if the ground on which it is placed is a soft ground or a ground that may cause liquefaction in the event of an earthquake, the ground itself loses its supporting force, and the foundation and the building are inclined. May end up. If the entire building including the foundation inclines in this way, the repair becomes large and the repair cost becomes large, so a foundation structure that can handle soft ground and liquefied ground has been proposed ( For example, see Patent Documents 1 and 2).

  The foundation structure described in Patent Document 1 is supported by being connected to a support body (pile part) that penetrates into the ground from the bottom plate of a building (structure), a buoyancy body provided on the support body, and the support body. An anchor body provided in the layer. In this foundation structure, even if the ground is liquefied and the bearing capacity is reduced, and groundwater rises due to excessive pore water pressure, the buoyancy due to this groundwater acts on the buoyant body to obtain the bearing capacity, and the anchor body tilts the building. It is a technology that tries to prevent.

  The foundation structure described in Patent Document 2 includes a foundation that supports a building, a sheet pile that surrounds the side of the foundation and penetrates into the ground, and a lightweight material that is provided in an area surrounded by the sheet pile below the foundation, Is provided. In this foundation structure, when the ground is liquefied and the bearing capacity is reduced, the foundation and the sheet pile are made to behave in an integrated manner, thereby suppressing the inclination of the foundation and the building. It is a technology that tries to secure the supporting force by acting on the foundation of the buoyancy of groundwater.

JP-A-6-240694 JP 2008-101379 A

  However, as in the foundation structure described in Patent Document 1, in order to construct a buoyancy body and an anchor body in the ground, the construction becomes very large, and an increase in cost is inevitable. It is difficult to apply to small-scale detached houses. Moreover, like the foundation structure described in patent document 2, when a foundation is enclosed with a sheet pile and a lightweight material is provided in the enclosed area, groundwater will always stay, and the retained groundwater will rot or May deteriorate. In addition, the buoyancy of the groundwater when the ground is liquefied and the buoyancy of the fluid in which the groundwater and sandy soil are turbid are not mechanically stable. In addition, since the buoyancy varies depending on the planar position of the building, it is difficult to effectively suppress the inclination of the entire building.

  Accordingly, an object of the present invention is to provide a foundation structure and a foundation construction method capable of improving the seismic performance by suppressing the inclination of the entire building and suppressing the transmission of seismic motion to the building.

In order to achieve the above object, the foundation structure according to claim 1 includes a foundation body connected to an upper structure of a building, a permeable layer provided between the foundation body and the ground, and a lower part from the permeable layer. comprising a plurality of pile body extending penetrate into the ground, and connecting means for connecting the pile body to the basic body, the said Kuitai a resin having a water permeability to form the outer surface of the該杭body A bag made of woven fabric, a granular material packed inside the bag, and a steel annular ring member that surrounds and restrains the outer periphery of the bag from the outside at a predetermined height position of the pile. Are characterized by comprising the above.

  The foundation structure according to claim 2 is the foundation structure according to claim 1, wherein the connecting means includes a core member provided through the inside of the pile body in the vertical direction, and a tip portion of the core member. It is characterized by having a front end fixing material that fixes to the front end portion of the pile body, and an upper end fixing material that fixes the upper end portion of the core material to the foundation body.

  The foundation structure according to claim 3 is the foundation structure according to claim 1 or 2, wherein an upper end portion of the pile body is penetrated into the water permeable layer by a predetermined length, and the penetration portion of the pile body and the water permeability An elastic member is provided between the layers.

  The foundation structure according to claim 4 is the foundation structure according to any one of claims 1 to 3, wherein a lower surface of the foundation body and an upper end portion of the pile body are provided apart from each other by a predetermined distance. The rigidity of the water-permeable layer is set to be smaller in the height range of the separation portion than in other height ranges.

  The foundation structure according to claim 5 is the foundation structure according to any one of claims 1 to 4, wherein the water permeable layer is formed by laminating a plurality of sandbag materials, and the sandbag material is a water permeable material. It is characterized in that it is configured by packing a granular material in a sandbag of a predetermined size having properties.

  The foundation construction method according to claim 6 is a foundation construction method according to any one of claims 1 to 5, wherein the ground is excavated according to the dimensions of the pile body, Set the bag of the pile body to which the connecting means is mounted in the excavated excavation hole, put the granular material into the set bag every predetermined amount and compact it, and at the upper position of the compacted granular material The ring member is mounted on the outside of the bag, and the piles are packed in the bag up to a predetermined height by repeatedly charging the granular material, compacting the granular material, and mounting the ring member. And forming the water permeable layer above the constructed pile body, constructing the foundation main body above the water permeable layer, and connecting the pile body to the foundation main body via the connecting means. It is characterized by that.

  According to the present invention as described above, a water permeable layer is provided between the foundation body and the ground, and a plurality of pile bodies extending from the water permeable layer into the ground below are provided, and the bag having water permeability and the inside thereof are packed. Even if the ground is liquefied at the time of an earthquake, the groundwater generated by excess pore water pressure due to liquefaction is drained to the ground via the pile body and the permeable layer. Can do. Therefore, it is possible to prevent excessive buoyancy due to groundwater from acting on the foundation body, and to suppress the inclination of the building due to non-uniform buoyancy, and the groundwater does not stay in the ground, and its decay and deterioration Can be prevented. In addition, the pile body can be constructed by filling the inside of the bag with a granular material, so the pile body can be constructed with a cheaper and easier construction procedure compared to reinforced concrete piles (cast-in-place piles or PC piles) or steel pipe piles. can do.

  In addition, since the pile body is constructed by packing the granular material inside the bag, the vertical load of the building can be supported by contact (contact) and friction between the granular materials, and it is liquefied during an earthquake. Even when an excessive shear displacement is generated in the softened ground, the granular material constrained by the bag can follow the displacement of the ground, and the pile body can be prevented from being damaged. Moreover, since the pile body is restrained by the ring member from the outer periphery of the bag, it is possible to suppress excessive deformation of the pile body while ensuring deformation followability by increasing the binding force of the granular material by the bag, The vertical support force can be secured to prevent the building from tilting. In addition, the granular material to be packed in the bag is not limited to soil, sand, crushed stone, etc., but may be a piece of glass, a piece of resin, etc., which is a material with little chemical change or change over time and has excellent load resistance. Those are preferred.

  Furthermore, since the pile body is connected to the foundation body by the connecting means, the pull-out resistance of the pile body against the upward load acting on the building and the foundation (for example, blast force due to typhoon or tornado, buoyancy due to excess pore water pressure) Force can prevent the foundation from rising and falling. At this time, the connecting means has a core material, a tip fixing material, and an upper end fixing material, and fixes the tip end portion of the core material to the tip end portion of the pile body by the tip fixing material, and also fixes the upper end portion of the core material to the upper end fixing material. By fixing to the foundation main body, the entire pile body and the foundation main body can be integrally connected, and the weight of the pile body can be effectively used as the pulling resistance force.

  Also, if the upper end of the pile body is penetrated into the permeable layer for a predetermined length and an elastic member is provided between the penetration part of this pile body and the permeable layer, the upper structure and foundation body of the building will be When displaced to the left and right, the elastic member can absorb the relative displacement that occurs between the pile body connected to the foundation body and the connecting means and the water permeable layer. In this way, the relative displacement of the water-permeable layer that is displaced integrally with the ground, the upper structure, the foundation body, and the pile body is absorbed by the elastic member, thereby making it difficult for the ground displacement during an earthquake to be transmitted to the building. The seismic isolation effect can be obtained and the seismic performance of the building can be improved. Furthermore, traffic vibrations transmitted from the ground can be blocked, and the habitability of the building can be improved.

  Moreover, if the rigidity of the water permeable layer is set to be smaller than the other height ranges in the height range of the separated portion between the lower surface of the foundation body and the upper end portion of the pile body, the permeable layer of the separated portion having a small rigidity is set. Can further enhance the seismic isolation effect (vibration isolation performance). That is, since the pile body and the foundation main body are isolated from each other by the water-permeable layer having a small rigidity at the separation portion, vibration transmission can be further reduced.

  In addition, if a water permeable layer is formed by laminating a plurality of sandbag materials made by packing granular materials in a sandbag bag of a predetermined size having water permeability, even if the gap between sandbag materials is filled with earth and sand Moreover, the water permeability by the sandbag and the internal granular material can be secured, and the groundwater can be drained more reliably. Moreover, since the transmission of seismic motion can be suppressed by the deviation between the granular materials and the sandbag material, the seismic isolation effect can be further improved. In addition, the granular material to be packed in the sandbag bag is not limited to soil, sand, crushed stone, etc., as in the granular material of the pile body, but may be a glass piece, a resin piece, etc. A material having a small amount of material and excellent load resistance is preferable. Moreover, the bag and granular material used for the pile body and the sandbag bag and granular material used for the sandbag material may be composed of the same material or may be composed of different materials.

It is a perspective view which shows the foundation structure of the building which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the lower part of the said building. It is a cross-sectional view which shows the basic part of the said building. It is sectional drawing which expands and shows the said foundation. It is sectional drawing which shows the construction procedure which builds the foundation of the said building. It is sectional drawing which shows the construction procedure of the said foundation following FIG. It is sectional drawing which shows the construction procedure of the said foundation following FIG. It is sectional drawing which shows the construction procedure of the said foundation following FIG.

  Hereinafter, the basic structure concerning one Embodiment of this invention is demonstrated based on FIGS. 1-4. The foundation structure according to the present embodiment supports a building body 2 as an upper structure of the building 1, and the building 1 is used for a detached house, an apartment, or the like. The building body 2 is a relatively small and light 2-3-story building such as a wooden structure or a lightweight steel structure, and has a rectangular shape along the X and Y directions which are two horizontal directions as shown in FIG. It has a well-shaped planar shape. The building 1 is constructed on the ground G, and this ground G is excavated from the ground surface GL downward in the Z direction, which is a vertical direction, to construct a foundation body 3, a permeable layer 4, and a pile body 5 described later.

  The foundation main body 3 includes a foundation rising 31 provided along the outer periphery of the building main body 2 and a foundation bottom slab 32 that is integrally connected to a lower end portion of the foundation rising 31 and extends in a horizontal plane. . Between the foundation bottom slab 32 and the floor and beams of the building body 2, foundation pits for arranging equipment piping and the like are formed. The depth of penetration of the foundation main body 3, that is, the distance from the ground surface GL to the lower surface of the foundation bottom slab 32 is set to, for example, about 450 mm, and the thickness dimension of the foundation bottom slab 32 is set to, for example, about 200 mm. ing. The rising dimension from the upper surface of the foundation bottom plate 32 to the upper end of the foundation rising 31 is set to about 600 mm, and the base of the building body 2 is connected to the upper end of the foundation rising 31 via an anchor bolt and a joint metal. .

  The water permeable layer 4 is configured by laminating a plurality of sandbag materials 4A. As the sandbag material 4A, for example, a glass piece is placed on a sandbag bag made of a woven fabric having water permeability such as polyethylene. And those filled with granular materials such as glass grains can be used. Since such a sandbag material 4A allows both sandbag bags and granular materials to pass water, the sandbag material 4A itself has water permeability, and an appropriate gap is formed between the stacked sandbag materials 4A. Water permeability is also obtained by the gap. The sandbag material 4A has a plane dimension of about 400 mm × 400 mm, a thickness dimension of about 70 mm or 100 mm, and the sandbag material 4A having a thickness of 70 mm is stacked in two stages from the lower surface of the foundation bottom slab 32 and is thick below it. The thickness of the water permeable layer 4 is set to about 740 mm by stacking the sandbag materials 4A having a thickness of 100 mm in six stages. Moreover, in the range along the outer periphery of the foundation main body 3, the sandbag material 4A is laminated | stacked to the surface GL vicinity, and groundwater can be discharged | emitted to the surface GL now.

  The pile body 5 penetrates the sandbag material 4A part having a thickness of 100 mm stacked six stages from the lower side of the sandbag material 4A having a thickness of 70 mm stacked in the middle of the water-permeable layer 4, It penetrates and extends into the ground G below, and for example, the pile length is set to 6 m. In addition, the pile body 5 is provided with a plurality of piles at appropriate intervals in the X and Y directions within a range corresponding to the planar shape of the foundation body 3, specifically, four rows along the X direction, Y A total of 12 lines in 3 rows are provided along the direction. As shown in FIG. 4, the pile body 5 includes a bag 5 </ b> A that forms the outer surface of the pile body 5 and has water permeability, and a granular material 5 </ b> B packed inside the bag 5 </ b> A. It is prepared for. The bag 5A is made of, for example, a woven fabric having water permeability such as polyethylene, and is formed in a long bottomed cylindrical shape having a diameter of about 600 to 800 mm. The granular material 5B has an appropriate size. It consists of glass pieces, glass grains, and the like. Therefore, the pile body 5 has water permeability because both the bag 5A and the granular material 5B pass water, and the pile head which is the upper end portion of the pile body 5 and the water permeable layer 4 are continuous. Therefore, the water transmitted through the pile body 5 can be drained from the water permeable layer 4 to the ground surface. In addition, regarding sandbag material 4A having a thickness of 6 mm stacked six-stage, it is partially replaced with lightweight concrete, foamed concrete, etc., thereby adjusting the weight of the entire foundation, and the buoyancy due to groundwater and the weight of building 1 are adjusted. You may make it balance.

  The pile body 5 includes a ring member 51 that surrounds and restrains the outer periphery of the bag 5 </ b> A at a predetermined height position, and is connected to the foundation body 3 by a connecting means 6. The ring member 51 is formed, for example, by bending a steel rod having a diameter of 9 mm into an annular shape and welding the tip, and the diameter is set to 400 mm. The ring member 51 is provided at predetermined intervals (for example, 1.2 m) along the length direction of the pile body 5, and the thickness of the pile body 5 is a ring at a position where the ring member 51 is provided. The expansion of the bag 5A is constrained so as to be equal to or less than the diameter of the member 51. On the other hand, in the position where the ring member 51 is not provided, the pile body 5 is expanded by the pressure of the granular material 5B packed inside and compacted, and the pile body 5 is pressed by pressing the inner surface of the excavation hole. The surrounding ground G is compacted.

  The connecting means 6 fixes the core member 61 provided so as to penetrate the inside of the pile body 5 in the vertical direction, and fixes the lower end portion (tip portion) of the core member 61 to the bottom portion of the bag 5 </ b> A that is the tip portion of the pile body 5. The front end fixing member 62 and the upper end fixing member 63 that fixes the upper end portion of the core member 61 to the base bottom plate 32 of the base body 3 are configured. The core member 61 is made of, for example, a round steel having a diameter of 25 mm, and a screw thread into which a nut 64 is screwed is formed at the upper and lower ends thereof, and has a length dimension protruding above the foundation bottom plate 32 from the tip of the pile body 5. It is a bar material. The core material 61 is not limited to a round steel, but may be a deformed reinforcing bar, a shaped steel, or a tension material such as a wire cable. The front-end fixing material 62 and the upper-end fixing material 63 are each made of a circular steel plate having a plate thickness of 16 mm and a diameter of 300 mm, and an insertion hole through which the core material 61 is inserted is formed at the center. The front end fixing member 62 is fixed to the bottom surface of the bag 5 </ b> A of the pile body 5 by a nut 64 screwed to the lower end portion of the core member 61, whereby the lower end portion of the core member 61 is fixed to the front end portion of the pile body 5. . The upper fixing member 63 is provided along the upper surface of the foundation bottom plate 32 of the foundation body 3 and is fixed by a nut 64 screwed into the upper end portion of the core member 61, whereby the upper end portion of the core member 61 is fixed to the foundation bottom plate 32. Has been.

  Further, an elastic member 7 is provided between a pile head (penetrating portion) of the pile body 5 penetrated into the water permeable layer 4 and the water permeable layer 4. The elastic member 7 is formed by, for example, overlapping an elastic ring 71 such as an annular and hollow rubber tube or a rubber tire in three stages and surrounding the pile head of the pile body 5. The horizontal relative displacement with the water permeable layer 4 can be absorbed. That is, when the ground G vibrates in the horizontal direction due to an earthquake, the ground acceleration and the inertial force from the building 1 act on the water permeable layer 4 in opposite directions, and the sandbags 4A laminated by this shearing force are left and right. The water permeable layer 4 is shear-deformed by shifting or by shifting the granular materials inside each sandbag material 4A. In particular, the sandbag material 4A having a thickness of 70 mm that is stacked between the lower surface of the foundation bottom slab 32 and the upper end of the pile 5 has a small density of granular materials and a small layer thickness. Since the shear rigidity is set small, a large shear deformation occurs between the foundation bottom slab 32 and the pile body 5. As the water permeable layer 4 undergoes shear deformation in this manner, the earthquake motion is not directly transmitted to the building 1, the shaking of the building 1 is reduced, and a seismic isolation effect is obtained. On the other hand, the shear deformation of the permeable layer 4 causes relative displacement between the building 1 and the ground G, and between the pile body 5 connected to the foundation body 3 by the connecting means 6 and the ground G. Relative displacement can be absorbed by elastic deformation of the elastic member 7.

  The construction procedure of the foundation structure as described above will be described with reference to FIGS. First, according to the construction position and pile length of the pile body 5, as shown in FIG. 5 (A), the ground G is excavated from the ground surface GL using a drilling device M1 such as an earth drill, for example, the inner diameter is about 450 mm. The excavation hole D is formed. Next, as shown in FIG. 5 (B), the ground G is excavated to expose the root cut bottom D1, and a charging device M2 such as a hopper is installed on the ground surface GL above the excavation hole D in the root cut bottom D1. To do. Further, the bag 5A, in which the core material 61 is attached to the bottom of the bag 5A via the tip fixing material 62, is set in the charging device M2, and the bag 5A is inserted into the excavation hole D so as to push in the core material 61.

  Next, as shown in FIG. 6A, the granular material 5B is charged into the bag 5A from the charging device M2, and the bag 5A is thereby expanded in the excavation hole D. When a predetermined amount of the granular material 5B is charged, a compacting device such as a vibrator is inserted into the bag 5A, the granular material 5B is vibrated and compacted, the bag 5A is expanded and the inner surface of the excavation hole D is pressed to press the ground G Tighten. Thereby, the bag 5A of the pile body 5 spreads to the side by the pressure of the granular material 5B, the inner surface of the excavation hole D is pressed, and the surrounding ground G is compacted. In addition, according to the shape of the pile body 5 to construct | assemble, you may excavate the excavation hole D by changing a hole diameter regarding a height direction. Next, as shown in FIG. 6B, the ring member 51 is dropped onto the outside of the bag 5A through the ring member 51, and the ring member 51 is positioned above the compacted granular material 5B. Thus, the granular material 5B is charged and compacted, and the installation of the ring member 51 is repeated for each predetermined height, and the granular material 5B is packed up to the lower surface position of the water permeable layer 4 to construct the most part of the pile body 5.

  Next, as shown in FIG. 7A, the elastic ring 71 is overlapped through the upper end of the bag 5A, the elastic member 7 is installed, and then the granular material 5B is packed into the bag 5A up to the upper end position of the elastic member 7. Then, the bag 5A is cut at the upper end position of the elastic member 7, and the cut bag 5A 'is removed, and the upper end edge of the bag 5A is tied to the core member 61 and fixed, or fixed to the elastic member 7. Next, as shown in FIG. 7 (B), a sandbag material 4A having a thickness of 100 mm is arranged and stacked on the surface of the root cutting bottom D2 so as to surround the periphery of the elastic member 7. Further, as shown in FIG. 8A, sandbag materials 4A having a thickness of 70 mm are arranged and laminated to form a water permeable layer 4. The laminating work of the sandbag material 4A may be performed manually, or may be performed using an appropriate apparatus or heavy equipment.

  Next, as shown in FIG. 8B, the foundation body 2 is constructed on the upper side of the water permeable layer 4, and then the sandbag material 4 </ b> A is laminated along the outer surface of the foundation rising 31. On the other hand, when constructing the base body 2, the core material 61 of the connecting means 6 is passed through the base bottom plate 32, the top body fixing member 63 is set on the core material 61 after the foundation body 2 is constructed, and the core A nut 64 is screwed onto the material 61 to fix the upper end fixing material 63. When the construction of the foundation structure is completed in this way, the building body 2 is constructed on the foundation rise 31 to complete the building 1.

  According to this embodiment, since the permeable layer 4 and the pile body 5 are formed continuously, even if the ground G rises and the groundwater rises during an earthquake, the permeable layer passes through the inside of the pile body 5. The groundwater can be sent to 4 and drained to the surface GL. Therefore, it is possible to prevent excessive buoyancy due to groundwater from acting on the foundation main body 3, and to suppress the inclination of the building 1 due to non-uniform buoyancy, and groundwater does not stay in the ground G. Corruption and deterioration can be prevented. Moreover, since the pile 5 is comprised by packing the granular material 5B in the bag 5A which has water permeability, and the water-permeable layer 4 is comprised by laminating the sandbag material 4A which has water permeability, the pile body 5 and water-permeable The water permeability of the layer 4 can be secured and the groundwater can be drained more reliably. Furthermore, since the pile body 5 can be constructed by packing the granular material 5B inside the bag 5A, the pile body 5 can be constructed by an inexpensive and easy construction procedure, and the construction cost can be suppressed and the construction period can be shortened. it can. Furthermore, since the pile body 5 and the foundation main body 3 are connected by the connecting means 6, the foundation is lifted or falls by the pulling resistance force of the pile body 5 against the upward load acting on the building body 2 or the foundation main body 3. Can be prevented.

  Even if excessive shear displacement occurs in the ground that has been liquefied and softened during the earthquake, the granular material 5B is restrained by the bag 5A and the pile body 5 restrained by the ring member 51 is displaced by the ground. The pile body 5 can be prevented from being damaged. Furthermore, at the time of construction of the pile body 5, the granular material 5B is compacted for every predetermined height, and the restraint degree of the granular material 5B by the bag 5A and the ring member 51 is increased by installing the ring member 51. As a result, it is possible to improve the deformation followability of the pile body 5 and to easily return to the initial state after the earthquake and to secure the vertical support force of the pile body 5. Furthermore, even if the ground G is liquefied, the shape of the pile body 5 itself is maintained, and after the pile body 5 is shaken in the ground G like a pendulum as a weight, it is restored to the initial position. The vertical supporting force can be maintained. In addition, since the permeable layer 4 undergoes shear deformation during an earthquake, seismic motion from the ground G can be prevented from being transmitted to the building 1, and a seismic isolation effect that suppresses the shaking of the building 1 can be obtained. Can be improved. Furthermore, since the vibration of the ground G is difficult to be transmitted to the building 1 by the water permeable layer 4, it is possible to suppress the transmission of traffic vibrations and improve the comfortability.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

  For example, in the above-described embodiment, the basic body 3 is of the basic type having the basic rising 31 and the basic bottom plate 32, but the basic main body may be of an independent basic type or a cloth basic type. Moreover, in the said embodiment, although the water permeable layer 4 was provided between the whole foundation main body 3 and the ground G, it may not be restricted to this, and may be provided partially in the plane of a foundation main body, In that case, the pile body should just be continuously provided in the water permeable layer provided partially. Moreover, in the said embodiment, although the bag 5A of the pile body 5 and the sandbag bag of the sandbag material 4A were comprised with the woven fabric made from polyethylene etc., the material of a bag etc. are not specifically limited, What has water permeability? That's fine. Furthermore, regarding the granular material 5B of the pile body 5 and the granular material of the sandbag material 4A, it is not limited to those composed of glass pieces or glass particles, but any material such as crushed stone or resin granular material may be used. Is possible.

1 Building 2 Building body (superstructure)
DESCRIPTION OF SYMBOLS 3 Base body 4 Water-permeable layer 4A Sandbag material 5 Pile body 5A Bag 5B Granule 6 Connection means 7 Elastic member 51 Ring member 61 Core material 62 Tip fixing material 63 Upper end fixing material

Claims (6)

A foundation body connected to the superstructure of the building;
A water permeable layer provided between the foundation body and the ground;
A plurality of pile bodies that penetrate and extend from the permeable layer into the ground below;
Connecting means for connecting the pile body to the foundation body,
The pile body forms a bag made of a resin woven fabric that forms the outer surface of the pile body and has water permeability, a granular material packed inside the bag, and a predetermined height position of the pile body. A steel annular ring member that surrounds and restrains the outer periphery of the bag from the outside of the bag.   The connecting means includes a core member provided through the pile body in the vertical direction, a tip fixing member for fixing the tip portion of the core member to the tip portion of the pile member, and an upper end portion of the core member. The foundation structure according to claim 1, further comprising: an upper end fixing material that is fixed to the foundation main body.   The upper end portion of the pile body is penetrated into the permeable layer by a predetermined length, and an elastic member is provided between the penetration portion of the pile body and the permeable layer. The basic structure described.   The lower surface of the foundation body and the upper end portion of the pile body are provided apart from each other by a predetermined distance, and in the height range of the separated portion, the rigidity of the water permeable layer is set smaller than other height ranges. The foundation structure according to any one of claims 1 to 3, wherein: The water permeable layer is configured by laminating a plurality of sandbag materials,
The foundation structure according to any one of claims 1 to 4, wherein the sandbag material is configured by packing a sandbag of a predetermined size having water permeability with a granular material. A foundation construction method according to any one of claims 1 to 5,
Excavate the ground according to the dimensions of the pile body, set the pile body bag with the connecting means in the excavated excavation hole, and put the granular material into the set bag every predetermined amount and compact At the same time, the ring member is mounted on the outside of the bag at the upper position of the compacted granular material, and these granular materials are repeatedly charged, the granular material is compacted, and the ring member is repeatedly mounted. Build the pile body by filling the bag up to a predetermined height position,
The permeable layer is formed on the upper part of the constructed pile body, the foundation body is constructed on the upper side of the permeable layer, and the pile body is connected to the foundation body through the connecting means. How to build a foundation.

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