JP2012046980A - Building foundation using earth retaining wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent an end of a base from being destroyed by undergoing tensile force from an earth retaining wall, when an external force directed in a direction orthogonal to the earth retaining wall acts on the earth retaining wall above the base having the end connected to the earth retaining wall.SOLUTION: A building foundation using an earth retaining wall provided in the ground includes: a base which is provided below a surface of the ground and perpendicular to the earth retaining wall, and has an end connected to the earth retaining wall; and a PC steel material which has one end fixed to the inside of the base, is horizontally elongated via the end from the base, and has the other end fixed to the outside of the base with tensile force introduced.

Description

  The present invention relates to a building foundation using a retaining wall provided in the ground.

  Conventionally, there are buildings that use retaining walls provided in the ground. The foundation has a bottom plate provided perpendicularly to the retaining wall below the surface of the ground, and the bottom plate has an end coupled to the retaining wall (see Patent Document 1).

JP 2003-147778 A

  The retaining wall above the bottom plate receives earth pressure and water pressure from the ground. At this time, the retaining wall is bent and deformed, and the end portion of the bottom plate receives a tensile force from the retaining wall. For this reason, when the said tensile force is remarkably large, there exists a possibility that the said edge part of the said bottom plate may be destroyed.

  An object of the present invention is to provide an end force of the bottom slab from the retaining wall when an external force in a direction perpendicular to the retaining wall is exerted on the retaining wall above the bottom slab having an end coupled to the retaining wall. It is to surely prevent them from being destroyed.

  The present invention is a bottom plate having an end coupled to a retaining wall, and a PC steel material having one end fixed inside the end of the bottom plate and extending in a horizontal direction from the bottom plate through the end. PC steel material into which tension was introduced with an end fixed outside the bottom plate. Accordingly, the end portion of the bottom plate receives a compressive force from the PC steel material, and when an external force in a direction orthogonal to the retaining wall above the bottom plate is applied, the end portion of the bottom plate is Prevent receiving tensile force from the retaining wall. This prevents the end portion of the bottom slab from breaking due to the tensile force from the earth retaining wall.

  The foundation of the building using the retaining wall provided in the ground according to the present invention is a bottom slab provided perpendicularly to the retaining wall below the surface of the ground and coupled to the retaining wall. A bottom plate having an end portion, and one end portion is fixed inside the bottom plate, extends horizontally from the bottom plate through the end portion, and the other end portion is fixed outside the bottom plate, and tension is introduced. PC steel materials.

  When an external force in a direction perpendicular to the retaining wall is applied to the retaining wall above the bottom plate, the retaining wall is bent and deformed to apply a tensile force to the end portion of the bottom plate. The foundation has the one end fixed inside the bottom plate, extends horizontally from the bottom plate through the end, and the other end is fixed to the retaining wall. Therefore, a compression force can be applied in advance to the end portion of the bottom slab by the PC steel material, and when the external force acts on the retaining wall above the bottom slab, the bottom plate has the bottom plate. It is possible to prevent the tensile force from being applied to the end portion. Thereby, it can prevent that the said edge part of the said bottom plate receives the said tensile force, and destroys.

  The foundation may have the other end of the PC steel material fixed to the retaining wall. In the foundation, the retaining wall has a through hole, the PC steel material passes through the through hole and reaches the inside of the ground, and the other end portion of the PC steel material is fixed to the ground. can do.

  According to the present invention, the PC steel material can apply a compressive force to the end portion of the bottom plate, and when an external force in a direction perpendicular to the retaining wall above the bottom plate acts on the bottom plate, The end portion can be prevented from receiving a tensile force from the earth retaining wall. Thereby, it can prevent reliably that the said edge part of the said bottom slab receives the said tensile force from the said earth retaining wall, and destroys.

The longitudinal cross-sectional view of the foundation of a building based on 1st Example of this invention. FIG. 3 is an enlarged view of a building foundation in line 2 of FIG. 1. FIG. 3 is a horizontal sectional view of the foundation of the building at line 3 in FIG. 2. The figure which shows having arrange | positioned PC steel materials above the ground at the time of construction of a foundation. The figure which shows having put the 1st concrete on the ground. The figure which shows having put the 2nd concrete on the ground. The longitudinal cross-sectional view of the foundation of a building based on 2nd Example of this invention. FIG. 8 is a horizontal sectional view of the foundation of the building at line 8 in FIG. 7.

  As shown in FIGS. 1 and 2, a building foundation 14 using a retaining wall 12 provided in the ground 10 is constructed. The foundation 14 has a bottom plate 18 provided perpendicular to the retaining wall 12 below the surface 16 of the ground 10, and the bottom plate has an end 20 coupled to the retaining wall 12. The foundation 14 has a side wall 22 provided parallel to the retaining wall 12 on the end 20 of the bottom plate 18, and the side wall is connected to the bottom plate 18 and the retaining wall 12. Each of the bottom plate 18 and the side wall 22 is made of reinforced concrete.

  The base 14 has a PC steel material 28 having one end 24 fixed to the inside of the bottom plate 18, extending horizontally from the bottom plate through the end 20, and the other end 26 fixed to the outside of the bottom plate 18. In the example shown in FIGS. 1 and 2, the other end 26 of the PC steel material 28 is fixed to the earth retaining wall 12. Tension is introduced into the PC steel material 28. The PC steel material 28 applies a compressive force to the end 20 of the bottom plate 18.

  An intermediate portion of the PC steel material 28 is covered with a sheath (not shown) and is not fixed to the bottom plate 18. A fixing plate 30 perpendicular to the PC steel material 28 is attached to one end portion 24 of the PC steel material 28, and the one end portion 24 is fixed inside the bottom plate 18 via the fixing plate 30.

  The retaining wall 12 is provided at a distance from the surface 32 of the retaining wall, and has a plurality of first protrusions 34 projecting from the surface 32 in the horizontal direction. 34 is accepted. The end 20 of the bottom plate 18 is coupled to the surface 32 of the retaining wall 12 and the first protrusion 34. The earth retaining wall 12 has a plurality of second protrusions 36 spaced from the surface 32 above the first protrusions 34, and the side wall 22 receives the second protrusions 36. The side wall 22 is coupled to the surface 32 of the retaining wall 12 and the second protrusion 36.

  The retaining wall 12 is a soil cement column wall, and as shown in FIG. 3, a main body 38 made of soil cement, and a plurality of steel members 40 that are arranged adjacent to the inside of the main body and extend in the vertical direction. Have A part of each steel material 40 is exposed from the main body 38, and each of the first protrusion 34 and the second protrusion 36 includes a stud fixed to the part of the steel material 40. The other end portion 26 of the PC steel material 28 is coupled to the steel material 40.

  The bottom surface of the bottom plate 18 is in contact with the ground 10. In the example shown in FIG. 1, the bottom plate 18 is positioned at a height higher than the lower end portion 12 a of the retaining wall 12, but may be positioned at the same height as the lower end portion 12 a of the retaining wall 12 instead. An upper structure 42 of the building is constructed on the bottom slab 18, and a seismic isolation device 44 is interposed between the bottom slab 18 and the upper structure 42.

  When constructing the foundation 14, first, a region of the ground 10 that is in contact with the retaining wall 12 is excavated from the surface 16 of the ground 10 to the lower end 12 a of the retaining wall 12 or above the lower end. Next, the bottom plate 18 is provided on the ground 10 in the region. At this time, first, as shown in FIG. 4, a mold 46 having a through hole 46 a parallel to the retaining wall 12 is disposed on the ground 10 in the region at a distance from the retaining wall 12 in the horizontal direction. Next, the PC steel material 28 extending in the horizontal direction is disposed above the ground 10 in the region so that the one end portion 24 of the PC steel material penetrates the through hole 46a, and the other end portion 26 of the PC steel material 28 is fixed to the earth. Secure to the wall 12.

  Thereafter, as shown in FIG. 5, the first concrete 18 a is placed on the ground 10 between the retaining wall 12 and the formwork 46 to a position above the PC steel material 28. After the first concrete 18a is cured, the mold 46 is removed from the first concrete 18a, and the fixing plate 30 is attached to the one end 24 of the PC steel material 28. Thereafter, tension is introduced into the PC steel material 28, and the one end 24 of the PC steel material 28 is fixed to the first concrete 18a via the fixing plate 30 while maintaining the state where the tension is introduced into the PC steel material 28. Thus, prestress is given to the 1st concrete 18a by the post tension method. Thereafter, as shown in FIG. 6, the second concrete 18b is placed on the ground 10 in the region to the position adjacent to the first concrete 18a. In this way, the bottom plate 18 is provided on the ground 10. Thereafter, a side wall 22 connected to the retaining wall 12 and parallel to the retaining wall 12 is provided on the bottom plate 18.

  Earth pressure and water pressure are applied from the ground 10 to the retaining wall 12 above the bottom plate 18. Further, a horizontal force acts on the retaining wall 12 above the bottom slab 18 at the time of an earthquake. Thus, when an external force in a direction perpendicular to the retaining wall 12 is applied to the retaining wall 12 above the bottom slab 18, the retaining wall 12 is bent and deformed and tries to apply a tensile force to the end 20 of the bottom slab 18. The foundation 14 is a PC steel material 28 having one end 24 fixed inside the bottom slab 18 and extending horizontally from the bottom slab through the end 20, and the other end 26 fixed to the earth retaining wall 12. Since the PC steel material 28 is provided, a compressive force can be applied in advance to the end portion 20 of the bottom slab 18 by the PC steel material, and when the external force acts on the soil retaining wall 12 above the bottom slab 18, the retaining wall 12. Thus, it is possible to prevent the tensile force from being applied to the end portion 20 of the bottom plate 18. Thereby, it can prevent that the edge part 20 of the bottom plate 18 receives the said tensile force, and destroys.

  The PC steel material 28 may be a PC steel wire, a PC steel stranded wire, or a PC steel rod. In the example shown in FIG. 2, the PC steel material 28 is located at the center of the bottom plate 18 in the thickness direction. Alternatively, the PC steel material 28 may be located above the center or located below the center. Also good. When the foundation 14 is constructed, instead of the above example in which prestress is applied to the first concrete 18a by the post tension method, prestress may be applied to the first concrete 18a by the pre tension method.

  In the example shown in FIGS. 7 and 8, the other end portion 26 of the PC steel material 28 is fixed to the ground 10 instead of the example shown in FIGS. 7 and 8 in which the other end portion 26 of the PC steel material 28 is fixed to the retaining wall 12. Has been. In this case, the earth retaining wall 12 has a through hole 48, and the PC steel material 28 passes through the through hole 48 and reaches the inside of the ground 10. A fixing tool 50 is attached to the other end portion 26 of the PC steel material 28, and the other end portion 26 is fixed to the ground 10 via the fixing tool 50.

  In the example shown in FIG. 7, when constructing the foundation 14, first, an area of the ground 10 that is in contact with the retaining wall 12 is excavated from the surface 16 of the ground 10 to below the through hole 48 of the retaining wall 12, and then A hole 52 that communicates with the through hole 48 and extends in the horizontal direction from the through hole is formed in the ground 10. Thereafter, a formwork (not shown) having a through hole parallel to the retaining wall 12 is disposed on the ground 10 in the region at a distance from the retaining wall 12 in the horizontal direction, and the PC steel material 28 extending in the horizontal direction. Is disposed above the ground 10 in the region so that one end 24 of the PC steel material penetrates the through hole of the mold and the other end 26 is received in the hole 52. The hole 52 is then filled with a curable material 54 such as cement milk. When the curable material 54 is cured, the other end 26 of the PC steel material 28 is fixed to the ground 10.

  Thereafter, the first concrete 18a is placed on the ground 10 between the retaining wall 12 and the formwork to a position above the PC steel material 28. After the first concrete 18a is cured, the mold is removed from the first concrete 18a, and the fixing plate 30 is attached to the one end 24 of the PC steel material 28. Thereafter, tension is introduced into the PC steel material 28, and the one end 24 of the PC steel material 28 is fixed to the first concrete 18a via the fixing plate 30 while maintaining the state where the tension is introduced into the PC steel material 28. Thereafter, the second concrete 18b is placed on the ground 10 in the region to the position adjacent to the first concrete 18a.

  The foundation 14 is a PC steel material 28 having one end 24 fixed to the inside of the bottom slab 18, extending in a horizontal direction from the bottom slab through the end 20, and reaching the inside of the ground 10 through the through hole 48 of the retaining wall 12. Thus, the other end portion 26 is fixed to the ground 10 and has the PC steel material 28 into which the tension is introduced. Therefore, a compressive force can be applied in advance to the end portion 20 of the bottom plate 18 by the PC steel material. It is possible to prevent the end portion 20 of the bottom slab 18 from receiving the tensile force from the retaining wall 12 when the external force acts on the retaining wall 12 at the upper side.

  By the way, when the other end portion 26 of the PC steel material 28 is fixed to the retaining wall 12, the retaining wall 12 receives a concentrated force from the PC steel material 28 into which the tension is introduced. For this reason, the retaining wall 12 must be thick enough to resist the tensile force, and the retaining wall 12 may be enlarged. On the other hand, when the other end portion 26 of the PC steel material 28 is fixed to the ground 10, the retaining wall 12 does not receive the tensile force from the PC steel material 28. For this reason, the retaining wall 12 does not need to resist the tensile force, and the retaining wall 12 is not enlarged.

  The retaining wall 12 may be a steel pipe sheet pile, a steel sheet pile, a parent pile horizontal sheet pile, or the like, instead of the illustrated example of a soil cement column wall. In the illustrated example, the building superstructure 42 is separated from the side wall 22, but may alternatively be coupled to the side wall 22. In this case, the side wall 22 may constitute a part of the upper structure 42.

DESCRIPTION OF SYMBOLS 10 Ground 12 Retaining wall 14 Foundation 16 Surface 18 Bottom plate 20 End part 24 One end part 26 Other end part 28 PC steel material 48 Through hole

Claims (3)

It is the foundation of a building using a retaining wall provided in the ground,
A bottom plate provided perpendicularly to the retaining wall below the surface of the ground and having an end coupled to the retaining wall;
One end portion is fixed inside the bottom plate, extends horizontally from the bottom plate through the end portion, and the other end portion is fixed outside the bottom plate. Basic.   The building foundation according to claim 1, wherein the other end portion of the PC steel material is fixed to the earth retaining wall.   The said retaining wall has a through hole, The said PC steel material penetrates the said through hole, and reaches the inside of the said ground, The said other end part of the said PC steel material is being fixed to the said ground. The foundation of the building.

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