Foundation of building and method for constructing foundation of building

Abstract

A foundation (10) of a building comprises: a foundation section (11) having a raised section (13); and a floor section (21) formed from concrete. The raised section (13) has a floor-receiving section (30). A floor end section (22) of the floor section (21) is supported by the floor-receiving section (30).

Description

Foundations of buildings and construction methods for foundations of buildings

[0001] The present disclosure relates to a building foundation and a method for constructing a building foundation.

[0002] A known example of a building foundation is a foundation having a base portion and a rising portion. The base portion is also called a footing. The foundation is installed in an excavated trench. The excavated trench is backfilled with backfill soil. A concrete slab may be installed on top of the backfill soil. The concrete slab may settle due to shrinkage of the backfill soil. In Patent Document 1, a support for supporting the concrete slab is installed in the footing of a continuous footing.

[0003] JP 2010-95920 A

[0004] The settlement of concrete floors is caused by the shrinkage of backfill soil. A method of supporting concrete floors that is less likely to settle even when the backfill soil shrinks is required.

[0005] (1) A foundation according to one aspect of the present disclosure is a foundation for a building, comprising a foundation portion having a raised portion and a concrete floor portion, the raised portion having a foundation support portion, and an end portion of the floor portion being supported by the foundation support portion. With this configuration, the floor portion is supported by the foundation support portion. Therefore, even if the soil backfilled in the excavation trench settles or shrinks, settlement of the floor portion can be suppressed.

[0006] (2) In the foundation of the building described in (1) above, the rising portion has a support member as the earthen floor support portion. With this configuration, the earthen floor edge can be supported by the support member. (3) In the foundation of the building described in (2) above, the rising portion is provided with an engagement portion for fixing the support member, and the support member is engaged with the engagement portion. With this configuration, the support member is fixed to the rising portion via the engagement portion.

[0007] (4) In the foundation for a building according to (3) above, the engaging portion has an anchor member provided on the rising portion and protruding from a side surface of the rising portion, and the support member is engaged with the anchor member. With this configuration, the engaging portion has the anchor member, so that the engaging portion is firmly fixed to the rising portion.

[0008] (5) In the foundation of the building described in (4) above, the anchor member is a separator that separates two forms used to form the rising portion. With this configuration, the separator used in foundation construction can be used as part of the anchor member for attaching the support member.

[0009] (6) In the building foundation described in any one of (2) to (5) above, the support member has a support member main body arranged so as to follow the side surface of the rising portion, and a slab end support portion provided on the support member main body, and when the support member is provided on the rising portion, the slab end support portion is provided on the support member main body so as to protrude from the side surface of the rising portion. With this configuration, the support member can be positioned on the side surface of the rising portion by the support member main body.

[0010] (7) In the foundation of the building described in (1) above, the rising portion has a step portion as the earth floor support portion, and the upper surface of the step portion is located at a lower position than the upper surface of the rising portion. With this configuration, the step portion of the rising portion can support the earth floor end.

[0011] (8) In the foundation of the building described in (1) above, the rising portion has a protruding portion that protrudes from a side surface of the rising portion as the earth floor support portion. With this configuration, the protruding portion of the rising portion can support the end of the earth floor.

[0012] (9) A construction method for a foundation of a building according to one aspect of the present disclosure is a construction method for a foundation having a raised portion and a slab, and includes the steps of: a first step of digging an excavation trench; a second step of forming the raised portion in the excavation trench so that a slab support portion is provided on the side of the raised portion to support the slab end portion of the slab; and a third step of forming the slab so that the slab end portion is connected to the slab support portion of the raised portion. With this configuration, the slab portion is supported by the slab support portion. This makes it possible to prevent the slab portion from subsiding if the soil backfilled in the excavation trench settles or shrinks.

[0013] (10) In the method for constructing a foundation for a building according to (9), in the second step, the earth support portion is formed together with the rising portion. With this configuration, it is not necessary to provide a separate step for forming the earth support portion after the second step. This makes it possible to improve the efficiency of foundation construction.

[0014] (11) In the method for constructing a foundation for a building according to (9) above, in the second step, the raised portion is formed, and then the earth support is provided on the raised portion. With this configuration, the earth support can be provided on the raised portion after the raised portion is formed. Therefore, if it is determined that soil shrinkage will occur after the soil is backfilled in the excavation trench, the earth support can be provided on the raised portion.

[0015] According to the building foundation and the building foundation construction method disclosed herein, subsidence of the earthen floor can be suppressed when the soil backfilled in the excavation trench subsides or shrinks.

[0016] FIG. 1 is a cross-sectional view of a foundation for a building in the first embodiment. FIG. 2 is a side view of the foundation for a building as viewed from the direction of arrow A in FIG. 1. FIG. 3 is an enlarged view of the earth support portion in FIG. 1. FIG. 4 is a cross-sectional view of a modified example of the foundation in the first embodiment. FIG. 5 is a cross-sectional view of a construction method for a foundation for a building. FIG. 6 is a cross-sectional view of a construction method for a foundation for a building. FIG. 7 is a cross-sectional view of a construction method for a foundation for a building. FIG. 8 is a cross-sectional view of a modified example of the earth support portion. FIG. 9 is a cross-sectional view of a modified example of the earth support portion. FIG. 10 is a cross-sectional view of a modified example of the foundation for a building.

[0017] First Embodiment A foundation 10 for a building according to this embodiment will be described with reference to Figures 1 to 11. The foundation 10 according to this embodiment is a deep foundation.

[0018] [Foundation of a Building] As shown in FIG. 1 , a foundation 10 of a building comprises a foundation portion 11 and a slab portion 21. The foundation portion 11 has a base portion 12 and a rising portion 13. The base portion 12 is provided in an excavation trench 4 formed by excavating the ground 1. The excavation trench 4 is provided in an area of ​​the ground 1 where the foundation portion 11 is to be provided. The ground 1 is divided into a first ground area 2 and a second ground area 3, sandwiched between them by the excavation trench 4. The first ground area 2 is a portion that extends outside the building in a plan view. The second ground area 3 is a portion that is located below the building in a plan view. The base portion 12 is provided so as to follow the excavation trench 4. The rising portion 13 is provided so as to extend upward from the base portion 12. The foundation portion 11 is made of reinforced concrete. The slab portion 21 is made of concrete. Reinforced bars may be buried in the slab portion 21.

[0019] The excavation trench 4 around the foundation 11 is backfilled with soil 5. In the backfilling operation, the soil 5 is returned to the excavation trench 4 so that the top surface of the buried portion is raised by a predetermined thickness. After one backfilling operation is completed, the backfilled soil 5 is compacted. Compaction is performed to harden the backfilled soil 5. The excavation trench 4 is backfilled with soil 5 up to the height of the top surface 2A of the first ground region 2 in the trench portion between the first ground region 2 and the foundation 10. The trench portion between the second ground region 3 and the foundation 10 is backfilled so that the top surface 33A of the earthen floor end support portion 33 (see below) is not buried in soil 5. That is, the excavation trench 4 is backfilled up to the height of the top surface 3A of the second ground region 3 in the trench portion between the side end portion 33B of the earthen floor end support portion 33 and the end portion 3B of the top surface 3A of the second ground region 3. Specifically, this trench portion is backfilled until the upper surface 3A of the second ground area 3 and the upper surface 5A of the soil 5 are at the same height. The soil 5 of the second ground area 3 is piled up so as to form a slope between the end 5B of the upper surface 5A of the soil 5 on the rising portion 13 side and the side end 33B of the slab end support portion 33. In short, the soil 5 backfilled between the second ground area 3 and the foundation 10 has a slope 5C.

[0020] 1 to 3, the rising portion 13 has a floor support portion 30 that supports the floor portion 21. Specifically, the rising portion 13 has a support member 31 as the floor support portion 30.

[0021] As shown in Figures 1 to 3, the support member 31 has a support member main body 32 and an earthen floor end support portion 33. The support member main body 32 is arranged so as to fit along the side surface 13A of the rising portion 13. The upper end 32A of the support member main body 32 is arranged so as to face upward. The support member main body 32 is fixed to the side surface 13A of the rising portion 13 with fasteners such as bolts 61. The earthen floor end support portion 33 is configured as a portion that supports the earthen floor end 22. The earthen floor end support portion 33 is provided on the support member main body 32. Specifically, when the support member 31 is provided on the rising portion 13, the earthen floor end support portion 33 is provided on the support member main body 32 so as to protrude from the side surface 13A of the rising portion 13. The earthen floor end support portion 33 is connected to the upper end 32A of the support member main body 32. The earthen floor end support portion 33 extends along the rising portion 13 in a plan view.

[0022] 1, 3, and 5, the structure for fixing the support member 31 to the rising portion 13 will be described. The rising portion 13 is provided with an engagement portion 40. The engagement portion 40 is provided on the rising portion 13 as a fixing means for fixing the support member 31 to the rising portion 13. A portion of the engagement portion 40 is embedded in the rising portion 13. This allows the engagement portion 40 to be firmly supported by the rising portion 13. The portion of the engagement portion 40 other than the embedded portion (hereinafter referred to as the exposed portion) is exposed from the rising portion 13. The exposed portion extends in a direction intersecting with the side surface 13A of the rising portion 13. Specifically, the exposed portion extends horizontally.

[0023] The engagement portion 40 has an anchor member 41. The anchor member 41 is provided on the rising portion 13. The anchor member 41 is provided so that a part of the anchor member 41 protrudes from the side surface 13A of the rising portion 13. The part protruding from the side surface 13A of the rising portion 13 corresponds to the exposed part described above.

[0024] As shown in FIGS. 1 and 5 , in this embodiment, the anchor member 41 is a separator 42. The separator 42 is a member for separating two riser portion forms 53 used to form the riser portion 13. The separator 42 includes a shaft portion 43, an attachment member 44, a first formwork engagement portion 45, and a second formwork engagement portion 46. The shaft portion 43 has a first end 43A and a second end 43B opposite the first end 43A. The second end 43B has a threaded portion. The first formwork engagement portion 45 is fixed to the riser portion form 53 and is configured to couple to the first end 43A of the shaft portion 43. The first formwork engagement portion 45 has a clamping portion 45A and a shaft coupling portion 45B extending from the clamping portion 45A. The clamping portion 45A is disposed between two riser portion formworks 53 stacked one above the other and is clamped by the two riser portion formworks 53. The axial connecting portion 45B is the portion that protrudes from the riser portion formwork 53 when the clamping portion 45A is disposed between the two riser portion formworks 53. The axial connecting portion 45B is the portion that connects to the first end 43A of the axial portion 43. The second formwork engagement portion 46 includes a connecting portion 46A that connects to the accessory member 44, a clamping portion 46B that is clamped between the two riser portion formworks 53, and an extension portion 46C that extends from the clamped portion. The extension portion 46C protrudes from the riser portion formworks 53. The extension portion 46C has a hole through which a fastening member 47 is inserted. The fastening member 47 is a wedge member that fastens the second formwork engagement portion 46 to the riser portion formwork 53.

[0025] The accessory member 44 is also called a P-con (plastic cone or foam tie cone). The accessory member 44 has a cover portion 44A that covers the second end 43B of the shaft portion 43 and detachably engages with the second end 43B of the shaft portion 43, and a protruding shaft 44B that protrudes from the cover portion 44A. The protruding shaft 44B engages with a second formwork engaging portion 46. The shaft unit formed by attaching the accessory member 44 to the second end 43B of the shaft portion 43 has a first formwork engaging portion 45 attached to one end and a second formwork engaging portion 46 attached to the other end.

[0026] The accessory member 44 is attached to the second end 43B of the shaft 43 so that the end face of the cover portion 44A contacts the side surface of the riser portion formwork 53 during construction of the riser portion 13. This allows the second end 43B of the shaft 43 to be exposed by removing the accessory member 44 from the shaft 43 embedded in the riser portion 13 when the riser portion 13 has hardened. When the accessory member 44 is removed from the shaft 43 in the hardened riser portion 13, a recess 48 (see FIG. 6 ) is created in the side surface 13A of the riser portion 13, where the cover portion 44A has been removed. The second end 43B of the shaft 43 is present in the recess 48. The second end 43B of the shaft 43 is used as the engagement portion 40 for fixing the support member 31.

[0027] The support member 31 is engaged with the engaging portion 40. Therefore, the support member 31 can be fixed to the side surface 13A of the rising portion 13 at the engaging portion 40. Specifically, the support member 31 is engaged with the anchor member 41. In this embodiment, the anchor member 41 is a separator 42. A second end portion 43B of the shaft portion 43 of the separator 42 and the support member body 32 of the support member 31 are fastened together with a bolt 61 and a nut 62. With this structure, the support member 31 is fixed to the engaging portion 40.

[0028] As shown in FIG. 10 , the earthen floor end support portion 33 of the support member 31 may be connected to the lower end 32B of the support member main body 32. [Support Structure of the Earthen Floor Section] As shown in FIG. 1 , the earthen floor end portion 22 of the earthen floor section 21 is supported by the earthen floor support portion 30 as follows. The earthen floor section 21 is arranged so as to face from the second ground area 3 toward the side surface 13A of the rising portion 13. The earthen floor section 21 contacts the upper surface 3A of the second ground area 3, the upper surface 5A of the soil 5, the slope 5C, the upper surface 33A of the earthen floor end support portion 33, and the side surface 13A of the rising portion 13. The earthen floor section 21 is arranged so as to be perpendicular to the side surface 13A of the rising portion 13. In FIG. 1 , the height of the upper surface 2A of the first ground area 2 and the height of the upper surface 21A of the earthen floor section 21 are at approximately the same level.

[0029] 4, the height of the upper surface 21A of the earthen floor portion 21 can be set lower than the height of the upper surface 2A of the first ground region 2. In this case, a water-stopping member 71 is provided near the center of the separator 42.

[0030] [Construction method for a building foundation] A construction method 50 for a building foundation 10 will be described with reference to Figures 5 to 9 and 11. As shown in Figures 5 to 9, construction of the building foundation 10 is carried out as follows. The construction method 50 for the foundation 10 includes a first step, a second step, and a third step.

[0031] As shown in Figure 5, in the first step, an excavation trench 4 is excavated. Specifically, the excavation trench 4 is provided by excavating the ground 1. Crushed stone 6 is placed at the bottom of the excavation trench 4. As shown in Figures 5 and 6, in the second step, a rising portion 13 is formed in the excavation trench 4. Specifically, a base portion formwork 51 and a rising portion formwork base 52 are placed on top of the crushed stone 6. The base portion formworks 51 are placed parallel to each other with a gap between them on top of the crushed stone 6. The base portion formworks 51 are components that determine the width of the base portion 12 when it is formed. The rising portion formwork bases 52 are placed between the two base portion formworks 51. The rising portion formworks 53 are placed parallel to each other with a gap between them on the rising portion formwork bases 52. The rising portion formworks 53 are placed one above the other. The rising portion formworks 53 are placed so that the spacing between the rising portion formworks 53 is narrower than the spacing between the base portion formworks 51. To increase the strength of the foundation 10, reinforcing steel bars 54 are placed between the two rising portion formworks 53. A separator 42 is placed between the two rising portion formworks 53. The separator 42 is fixed to one of the rising portion formworks 53 by a first formwork engaging portion 45. The separator 42 is fixed to the other rising portion formwork 53 by a second formwork engaging portion 46. The spacing between the two rising portion formworks 53 arranged in parallel is maintained by the separator 42.

[0032] As shown in Fig. 7, the rising portion 13 is formed in the excavation trench 4 so that a soil support portion 30 is provided on the side surface 13A of the rising portion 13. In this embodiment, the rising portion 13 has a support member 31 as the soil support portion 30. The support member 31 is provided on the rising portion 13 as follows.

[0033] As shown in Figures 5 to 7, in the second step, the earth support portion 30 is formed together with the rising portion 13. Specifically, concrete is poured between the parallel-arranged base portion formwork 51 and the parallel-arranged rising portion formwork 53. Once the concrete has hardened, the base portion formwork 51 and the rising portion formwork 53 are removed. The separator 42 is embedded in the rising portion 13. When the accessory member 44 is removed from the shaft portion 43 of the embedded separator 42, a recess 48 is formed in the side surface 13A of the rising portion 13, with the cover portion 44A removed. The second end 43B of the shaft portion 43 is present in the recess 48.

[0034] As shown in Figure 7, the support member 31 is placed on the side surface 13A of the rising portion 13 as follows: The second end 43B of the separator 42 has a threaded portion. The support member 31 is fastened to the second end 43B of the shaft portion 43 of the separator 42 with a bolt 61 and a nut 62. This fixes the support member 31 to the side surface 13A of the rising portion 13.

[0035] As shown in Figure 11, in the second step, after the rising portion 13 is formed, the earth support portion 30 may be provided on the rising portion 13. Specifically, after the rising portion 13 is formed, an insertion hole 72 is formed in the side surface 13A of the rising portion 13. An anchor member 41 is inserted into the insertion hole 72. The anchor member 41 is positioned so that the end 41A of the anchor member 41 protrudes from the side surface 13A of the rising portion 13. The end 41A of the anchor member 41 has a threaded portion. The support member 31 is fixed to the side surface 13A of the rising portion 13 with a nut 62.

[0036] Next, as shown in FIG. 8 , soil 5 is backfilled into the excavation trench 4. In the backfilling operation, the soil 5 is returned to the excavation trench 4 so that the top surface of the buried portion is raised by a predetermined thickness. After one backfilling operation is completed, the backfilled soil 5 is compacted. Compaction is performed to harden the backfilled soil 5. The excavation trench 4 is backfilled to the height of the top surface 2A of the first ground area 2 in the trench portion between the first ground area 2 and the foundation 10. The trench portion between the second ground area 3 and the foundation 10 is backfilled so that the top surface 33A of the earthen floor end support portion 33 is not buried in the soil 5. As described above, the soil 5 in the second ground area 3 is piled up so that a slope is formed between the end 5B of the top surface 5A of the soil 5 on the rising portion 13 side and the side end 33B of the earthen floor end support portion 33.

[0037] As shown in FIG. 9 , the third step involves forming the earthen floor portion 21. The earthen floor portion 21 is formed so that the earthen floor end portion 22 is connected to the earthen floor support portion 30 of the rising portion 13. Specifically, the earthen floor portion 21 is formed so as to extend from the second ground region 3 toward the side surface 13A of the rising portion 13. The earthen floor portion 21 is made of concrete. Reinforcement bars may be embedded in the earthen floor portion 21. The earthen floor portion 21 contacts the upper surface 3A of the second ground region 3, the upper surface 5A of the soil 5, the inclined surface 5C, the upper surface 33A of the earthen floor end support portion 33, and the side surface 13A of the rising portion 13. The earthen floor portion 21 is formed so as to be perpendicular to the side surface 13A of the rising portion 13.

[0038] [Operation of this embodiment] The operation of this embodiment will be described. The foundation 10 of the building comprises a foundation portion 11 having a rising portion 13, and an earthen floor portion 21 made of concrete. The rising portion 13 has an earthen floor support portion 30. An earthen floor end portion 22 of the earthen floor portion 21 is supported by the earthen floor support portion 30. With this configuration, the earthen floor portion 21 is supported by the earthen floor support portion 30. Therefore, even if the soil 5 backfilled in the excavation trench 4 settles or shrinks, settlement of the earthen floor portion 21 can be suppressed.

[0039] [Effects of this embodiment] The effects of this embodiment will be described. (1) The foundation 10 of the building comprises a foundation portion 11 having a rising portion 13, and an earthen floor portion 21 made of concrete. The rising portion 13 has an earthen floor support portion 30. An earthen floor end portion 22 of the earthen floor portion 21 is supported by the earthen floor support portion 30. According to this configuration, the earthen floor portion 21 is supported by the earthen floor support portion 30. Therefore, even if the soil 5 backfilled in the excavation trench 4 settles or shrinks, settlement of the earthen floor portion 21 can be suppressed.

[0040] (2) In the foundation 10 of the building, the rising portion 13 has a support member 31 as a floor support portion 30. With this configuration, the support member 31 can support the floor end portion 22. (3) In the foundation 10 of the building, the rising portion 13 is provided with an engagement portion 40 that fixes the support member 31. The support member 31 is engaged with the engagement portion 40. With this configuration, the support member 31 is fixed to the rising portion 13 via the engagement portion 40.

[0041] (4) In the foundation 10 of the building, the engaging portion 40 has an anchor member 41 that is provided on the rising portion 13 and protrudes from the side surface 13A of the rising portion 13. The support member 31 is engaged with the anchor member 41. With this configuration, the engaging portion 40 has the anchor member 41, so that the engaging portion 40 is firmly fixed to the rising portion 13.

[0042] (5) In the foundation 10 of the building, the anchor member 41 is a separator 42 that separates two rising portion formworks 53 used to form the rising portion 13. With this configuration, the separator 42 used in the foundation construction can be used as part of the anchor member 41 for attaching the support member 31.

[0043] (6) In the foundation 10 of the building, the support member 31 has a support member main body 32 arranged along the side surface 13A of the rising portion 13, and a slab end support portion 33 provided on the support member main body 32. The slab end support portion 33 is provided on the support member main body 32 so as to protrude from the side surface 13A of the rising portion 13 when the support member 31 is provided on the rising portion 13. With this configuration, the support member 31 can be positioned on the side surface 13A of the rising portion 13 by the support member main body 32.

[0044] (7) The construction method 50 for the foundation 10 includes a first step, a second step, and a third step. In the first step, an excavation trench 4 is excavated. In the second step, a rising portion 13 is formed in the excavation trench 4. In the second step, the rising portion 13 is formed so that a soil support portion 30 that supports the soil end portion 22 of the soil portion 21 is provided on the side surface 13A of the rising portion 13. In the third step, the soil portion 21 is formed so that the soil end portion 22 is connected to the soil support portion 30 of the rising portion 13. With this configuration, the soil portion 21 is supported by the soil support portion 30. As a result, settlement of the soil portion 21 can be suppressed when the soil 5 backfilled in the excavation trench 4 settles or shrinks.

[0045] (8) In the construction method 50 for the foundation 10, in the second step, the earth support portion 30 is formed together with the rising portion 13. With this configuration, it is not necessary to provide a step of forming the earth support portion 30 after the second step. This makes it possible to improve the efficiency of construction of the foundation 10.

[0046] (9) In the construction method 50 for the foundation 10 having the rising portion 13 and the slab portion 21, in the second step, the rising portion 13 may be formed, and then the slab portion 30 may be provided on the rising portion 13. According to this configuration, the rising portion 13 may be formed, and then the slab portion 30 may be provided on the rising portion 13. Therefore, if it is determined that the soil 5 will shrink after the excavation trench 4 is backfilled with the soil 5, the slab portion 30 can be provided on the rising portion 13.

[0047] Second Embodiment A foundation 10 for a building according to a second embodiment will be described with reference to Fig. 12. In this embodiment, components common to the first embodiment are assigned the same reference numerals as those in the first embodiment, and descriptions of overlapping components will be omitted.

[0048] 12 , a foundation 10 of a building includes a foundation portion 11 and a dirt floor portion 21. The foundation portion 11 has a base portion 12 and a rising portion 13.

[0049] [Earthenware Receiving Portion] As shown in Figure 12, the rising portion 13 has a step portion 15 as the earthenware receiving portion 30. Specifically, the rising portion 13 has a rising portion main body 14 and a step portion 15. The step portion 15 is provided on the second ground area 3 side of the rising portion main body 14. The rising portion main body 14 and the step portion 15 are integrally formed in the rising portion 13. An upper surface 15A of the step portion 15 is located lower than an upper surface 13B of the rising portion 13. Furthermore, the upper surface 15A of the step portion 15 is located lower than an upper surface 3A of the second ground area 3.

[0050] As shown in Figure 12, soil 5 is backfilled in the excavation trench 4. In the trench portion between the first ground area 2 and the foundation 10, the excavation trench 4 is backfilled with soil 5 up to the height of the upper surface 2A of the first ground area 2. The trench portion between the second ground area 3 and the foundation 10 is positioned so that the upper surface 15A of the step 15 is not buried in the soil 5. As described above, the soil 5 in the second ground area 3 is piled up so that a slope is formed between the end 5B of the upper surface 5A of the soil 5 on the rising portion 13 side and the side end 15B of the step 15.

[0051] [Support structure of earth floor section] As shown in Figure 12, the earth floor end section 22 of the earth floor section 21 is supported by the earth floor support section 30 as follows. The step section 15 in this embodiment corresponds to the earth floor support section 30. The earth floor section 21 is formed so as to extend from the second ground area 3 toward the side surface 14A of the rising section main body 14. The earth floor section 21 contacts the upper surface 3A of the second ground area 3, the upper surface 5A of the soil 5, the inclined surface 5C, the upper surface 15A of the step section 15, and the side surface 14A of the rising section main body 14. The earth floor section 21 is formed so as to be perpendicular to the side surface 14A of the rising section main body 14. As a result, the earth floor end section 22 is supported by the upper surface 15A of the step section 15.

[0052] <Effects> The effects of this embodiment will be described. In the foundation 10 of the building, the rising portion 13 has a step portion 15 as the floor support portion 30. The upper surface 15A of the step portion 15 is located lower than the upper surface 13B of the rising portion 13. With this configuration, the step portion 15 of the rising portion 13 can support the floor end portion 22.

[0053] Third Embodiment A building foundation 10 according to a third embodiment will be described with reference to Fig. 13. In this embodiment, components common to the first and second embodiments are denoted by the same reference numerals as those in the first and second embodiments, and descriptions of overlapping components will be omitted.

[0054] 13 , a foundation 10 of a building includes a foundation portion 11 and an earthen floor portion 21. The foundation portion 11 has a base portion 12 and a rising portion 13.

[0055] [Earth Receiving Portion] As shown in Figure 13, the rising portion 13 has a protruding portion 16 as the earth receiving portion 30. Specifically, the protruding portion 16 is provided closer to the second ground area 3 than the rising portion 13. The rising portion 13 and the protruding portion 16 are formed integrally. The protruding portion 16 protrudes from the side surface 13A of the rising portion 13. In addition, the upper surface 16A of the protruding portion 16 is located lower than the upper surface 3A of the second ground area 3.

[0056] As shown in Figure 13, soil 5 is backfilled in the excavation trench 4. In the trench portion between the first ground area 2 and the foundation 10, the excavation trench 4 is backfilled with soil 5 up to the height of the upper surface 2A of the first ground area 2. The trench portion between the second ground area 3 and the foundation 10 is positioned so that the upper surface 16A of the protruding portion 16 is not buried in the soil 5. As described above, the soil 5 in the second ground area 3 is piled up so as to form a slope on the upper surface 5A of the soil 5 between the end 5B on the rising portion 13 side and the side end 16B of the protruding portion 16.

[0057] [Support structure of earth floor portion] As shown in Figure 13, the earth floor end portion 22 of the earth floor portion 21 is supported by the earth floor support portion 30 as follows. In this embodiment, the protruding portion 16 corresponds to the earth floor support portion 30. The earth floor portion 21 is formed so as to extend from the second ground area 3 toward the side surface 13A of the rising portion 13. The earth floor portion 21 contacts the upper surface 3A of the second ground area 3, the upper surface 5A of the soil 5, the inclined surface 5C, the upper surface 16A of the protruding portion 16, and the side surface 13A of the rising portion 13. The earth floor portion 21 is formed so as to be perpendicular to the side surface 13A of the rising portion 13. As a result, the earth floor end portion 22 is supported by the upper surface 16A of the protruding portion 16.

[0058] <Effects> The effects of this embodiment will be described. In the foundation 10 of the building, the rising portion 13 has a protruding portion 16 that protrudes from the side surface 13A of the rising portion 13 as the floor support portion 30. With this configuration, the protruding portion 16 of the rising portion 13 can support the floor end portion 22.

[0059] <Modifications> The above-described embodiments are examples of possible forms of the building foundation 10 and the construction method 50 for the building foundation 10, and are not intended to limit the forms. The building foundation 10 and the construction method 50 for the building foundation 10 may take forms different from those exemplified in the above-described embodiments. Examples of such forms include forms in which part of the configuration of the embodiment is replaced, modified, or omitted, or forms in which a new configuration is added to the embodiment. Modifications of the embodiments are shown below.

[0060] The upper surface 21A of the earthen floor portion 21 may be higher than the upper surface 2A of the first ground region 2. For example, when a building is constructed on sloping ground, the upper surface 21A of the earthen floor portion 21 may be higher than the upper surface 2A of the first ground region 2.

[0061] The earthen floor section 21 may be provided not only on the second ground area 3 side but also on the first ground area 2 side. For example, an equipment earthen floor section 21 for installing equipment such as a water heater may be placed in the first ground area 2. In this case, the equipment earthen floor section 21 is formed so as to be connected to an earthen floor support section 30 provided on the outside of the rising section 13. The earthen floor support section 30 provided on the outside of the rising section 13 has a structure similar to the earthen floor support section 30 of the first embodiment.

[0062] The thickness of the earthen floor end portion 22 is greater than the thickness of the earthen floor portion 21 (hereinafter referred to as the intermediate thickness) provided on the upper surface 3A of the second ground area 3 and the upper surface 5A of the soil 5, but the thickness of the earthen floor end portion 22 may be approximately the same as the intermediate thickness. In this case, the upper surface of the earthen floor receiving portion 30 is located at the same height as the upper surface 3A of the second ground area 3.

[0063] In this embodiment, the earthen floor end portion 22 is arranged so as to contact the upper surface 33A of the earthen floor end portion support portion 33 of the support member 31, but it may also be arranged so as to cover the entire support member 31.

[0064] In the first embodiment, the earthen floor end support portion 33 of the support member 31 is provided at the upper end 32A of the support member main body 32. Alternatively, the earthen floor end support portion 33 may be provided at each of the upper end 32A of the support member main body 32 and the lower end 32B of the support member main body 32.

[0065] This specification discloses the following technology. [Supplementary Note 1] Supplementary Note 1 is a foundation for a building. The foundation for the building comprises a base portion having a rising portion and a concrete floor portion. The rising portion has a floor support portion. The floor end portion of the floor portion is supported by the floor support portion.

[0066] [Supplementary Note 2] In the foundation of the building described in Supplementary Note 1, the rising portion has a support member as the earth support portion.

[0067] [Supplementary Note 3] In the foundation for a building described in Supplementary Note 2, the rising portion is provided with an engagement portion for fixing the support member. The support member is engaged with the engagement portion.

[0068] [Supplementary Note 4] In the foundation for a building described in Supplementary Note 3, the engaging portion has an anchor member provided on the rising portion and protruding from a side surface of the rising portion. The support member is engaged with the anchor member.

[0069] [Supplementary Note 5] In the foundation for a building described in Supplementary Note 4, the anchor member is a separator that separates two forms used to form the rising portion.

[0070] [Supplementary Note 6] In the building foundation described in Supplementary Note 2, the support member has a support member main body arranged along the side surface of the rising portion, and a slab end support portion provided on the support member main body. When the support member is provided on the rising portion, the slab end support portion is provided on the support member main body so as to protrude from the side surface of the rising portion.

[0071] [Supplementary Note 7] In the foundation of the building described in Supplementary Note 1, the rising portion has a step portion as the earth support portion, and the upper surface of the step portion is located at a lower position than the upper surface of the rising portion.

[0072] [Supplementary Note 8] In the foundation of the building described in Supplementary Note 1, the rising portion has a protruding portion that protrudes from a side surface of the rising portion as the earth support portion.

[0073] [Appendix 9] Appendix 9 is a construction method for a foundation of a building. The construction method for a foundation having a rising portion and a slab includes a first step, a second step, and a third step. In the first step, an excavation trench is excavated. In the second step, the rising portion is formed in the excavation trench. In the second step, the rising portion is formed so that a slab support portion that supports the slab end portion of the slab portion is provided on the side of the rising portion. In the third step, the slab portion is formed so that the slab end portion is connected to the slab support portion of the rising portion.

[0074] [Supplementary Note 10] In the method for constructing a foundation for a building described in Supplementary Note 9, the second step forms the earth support portion together with the rising portion.

[0075] [Supplementary Note 11] In the method for constructing a foundation for a building according to Supplementary Note 9, in the second step, after forming the rising portion, the floor support portion is provided on the rising portion.

[0076] 4...excavation trench, 10...foundation, 13...rising portion, 13A...side of rising portion, 15...step portion, 15A...upper surface of step portion, 16...protruding portion, 21...earth floor portion, 22...earth floor end portion, 30...earth floor support portion, 31...support member, 32...support member main body, 33...earth floor end support portion, 40...engaging portion, 41...anchor member, 42...separator, 50...construction method.

Claims

1. A foundation for a building, comprising a base portion having a rising portion and a floor portion made of concrete, wherein the rising portion has a floor support portion, and the floor end of the floor portion is supported by the floor support portion.

2. The foundation according to claim 1, wherein the rising portion has a support member as the earth support portion.

3. The foundation according to claim 2, wherein the rising portion is provided with an engagement portion for fixing the support member, and the support member is engaged with the engagement portion.

4. The foundation according to claim 3, wherein the engagement portion has an anchor member provided on the rising portion and protruding from a side surface of the rising portion, and the support member is engaged with the anchor member.

5. The foundation according to claim 4, wherein the anchor member is a separator that separates two forms used to form the rising portion.

6. A foundation as claimed in any one of claims 2 to 5, wherein the support member has a support member main body arranged along the side of the rising portion and a floor end support portion provided on the support member main body, and when the support member is provided on the rising portion, the floor end support portion is provided on the support member main body so as to protrude from the side of the rising portion.

7. The foundation according to claim 1, wherein the rising portion has a step portion as the earth support portion, and the upper surface of the step portion is located at a lower position than the upper surface of the rising portion.

8. The foundation according to claim 1, wherein the rising portion has a protruding portion that protrudes from a side surface of the rising portion as the earth support portion.

9. A method for constructing a foundation having a rising portion and a floor section for a building, comprising: a first step of digging an excavation trench; a second step of forming the rising portion in the excavation trench so that a floor support section that supports the floor end section of the floor section is provided on the side of the rising portion; and a third step of forming the floor section so that the floor end section is connected to the floor support section of the rising portion.

10. A method for constructing a foundation for a building as described in claim 9, wherein in the second step, the earth support portion is formed together with the rising portion.

11. A method for constructing a foundation for a building as described in claim 9, wherein in the second step, after forming the rising portion, the earth support portion is provided on the rising portion.

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