Precast concrete foundation

Abstract

To provide a precast concrete foundation having high shearing strength in both vertical and horizontal directions in a joint part of a concrete foundation block, and having no risk of locally reducing the shearing strength in an area of a filling port of a grout material.SOLUTION: A precast concrete foundation 100 for supporting an upper structure of a building is formed by placing a grout material 50 in a gap G between a first end face 12 and a second end face 13 of a plurality of precast concrete foundation blocks 10 adjacent to each other, wherein three rows of shear cotters are provided in each of the first end face 12 and the second end face 13 in the longitudinal direction, and the shear cotters in the center row 20 are continuous in the longitudinal direction with concave portions 22 extending in the lateral direction, and the shear cotters in the left and right rows 30 are continuous in the longitudinal direction with convex portions 33 extending in the lateral direction. The concave portions 22 of the first end surface 12 and the second end surface 13 face each other, and the convex portions 32 of the first end surface 12 and the second end surface 13 face each other.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a precast concrete foundation. [Background technology]

[0002] In order to shorten the construction period for building foundations and increase the dimensional accuracy of the foundation, a construction method is applied in which the rising portion of the foundation is manufactured as a concrete foundation block (precast concrete foundation block) in a factory, and these concrete foundation blocks are transported to the construction site and used for foundation construction. By laying multiple concrete foundation blocks transported to the construction site in the direction of the foundation extension, and constructing footings on site below the rising portion of the concrete foundation blocks so that they are integrated with the rising portion, the construction period for foundations such as strip footings can be significantly shortened.

[0003] In precast concrete foundations, adjacent concrete foundation blocks are joined by filling the gaps between them in the extension direction of the foundation with grout material.In order to increase the shear strength at the joint, shear cotters are provided on the opposing end faces of both concrete foundation blocks, and the grout material filled in the gaps between the end faces is allowed to penetrate into the shear cotters and harden.

[0004] Box-shaped shear cotters are commonly used for this purpose, but because the area required to bear shear force is generally small, they pose a problem in terms of shear strength. Patent Document 1 proposes a precast concrete foundation material that solves this problem. The shear cotter provided on the end surface of the precast concrete foundation material disclosed therein has a shape in which multiple protrusions of a certain height are arranged horizontally at equal intervals, one above the other, and this configuration results in a wavy shear cotter with alternating peaks and valleys of a predetermined height. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-25667 Summary of the Invention [Problem to be solved by the invention]

[0006] The precast concrete foundation material described in Patent Document 1 is a wavy shear cotter with alternating peaks and valleys of a certain height formed in the horizontal direction, so while it has high vertical shear strength, it has issues with resistance to horizontal shear force and torsion.

[0007] In addition, in Patent Document 1, a relatively large box-shaped grout filling port is provided at the top of the end face of the precast concrete foundation material, and since there is no wavy shear cotter in the area of ​​this filling port, the shear strength is significantly reduced locally.

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a precast concrete foundation consisting of a plurality of precast concrete foundation blocks joined in the extension direction of the foundation, in which the joints of the concrete foundation blocks have high shear strength in both the vertical and horizontal directions, and there is no risk of localized reduction in shear strength in the area of ​​the grout filling port. [Means for solving the problem]

[0009] In order to achieve the above object, one aspect of the precast concrete foundation according to the present invention is as follows: A precast concrete foundation for supporting a superstructure of a building, which is formed by a plurality of precast concrete foundation blocks, in which a first end face of one adjacent concrete foundation block faces a second end face of the other adjacent concrete foundation block with a gap therebetween, and the gap is filled with grout material; Both the first end surface and the second end surface are provided with three rows of shear cotters in the vertical direction, The shear cotter in the center row has horizontally extending recesses that are continuous vertically, The left and right rows of shear cotters have horizontally extending convex portions that are continuous vertically. The recesses of the first end face and the second end face face each other, and the protrusions of the first end face and the second end face face each other.

[0010] According to this aspect, three vertical rows of shear cotters are provided on the first end face of one adjacent concrete foundation block and the second end face of the other adjacent concrete foundation block, with the central row of shear cotters having horizontally extending concave portions that are continuous vertically, and the left and right rows of shear cotters having horizontally extending convex portions that are continuous vertically, with the concave portions on the first end face and the convex portions on the second end face facing each other, so that of the grout material filled in the gap between the first end face and the second end face, the grout material filled in the pair of central row shear cotters forms vertically extending columns, resulting in the formation of a precast concrete foundation with high resistance to horizontal shear forces and torsion. Furthermore, the grout material filled in the pair of central row shear cotters and the pair of left and right rows of shear cotters also provides a precast concrete foundation with high resistance to vertical shear forces.

[0011] Furthermore, since each of the pair of central rows of shear cotters is formed with multiple recesses, the gap between the pair of central rows of shear cotters becomes a filling port for the grout material, and since shear cotters are also formed in this filling port, there is no risk of a significant local decrease in shear strength in the area of ​​the filling port.

[0012] Here, a "concave portion extending laterally" literally means a concave portion that is long in the horizontal direction and recessed toward the inside of the concrete foundation block, while a "convex portion extending laterally" literally means a convex portion that is long in the horizontal direction and protrudes toward the outside of the concrete foundation block (toward the other concrete foundation block).

[0013] In the precast concrete foundation material described in Patent Document 1, alternating peaks (convex portions) and valleys (concave portions) face each other to form a wavy shear cotter in the vertical direction, whereas in this embodiment, the concave portions face each other in the center row and the convex portions face each other in the left and right rows, thereby alternating narrow and wide regions in the vertical direction and forming spaces with different gap widths between the center row and the left and right rows, which are filled with grout. In this way, by forming shear cotter with different configurations in both the vertical and horizontal directions, it is possible to increase the shear strength in both the vertical and horizontal directions.

[0014] Another aspect of the precast concrete foundation according to the present invention is A precast concrete foundation for supporting a superstructure of a building, which is formed by a plurality of precast concrete foundation blocks, in which a first end face of one adjacent concrete foundation block faces a second end face of the other adjacent concrete foundation block with a gap therebetween, and the gap is filled with grout material; Both the first end surface and the second end surface are provided with three rows of shear cotters in the vertical direction, The shear cotter in the center row has horizontally extending recesses that are continuous vertically, The left and right rows of shear cotters have a series of pyramidal or truncated pyramidal convex portions running vertically. The recesses of the first end face and the second end face face each other, and the protrusions of the first end face and the second end face face each other.

[0015] According to this aspect, three vertical rows of shear cotters are provided on the first end face of one adjacent concrete foundation block and the second end face of the other adjacent concrete foundation block. The central row of shear cotters has horizontally extending recesses that are continuous vertically, and the left and right rows of shear cotters have vertically continuing pyramidal or truncated pyramidal protrusions. The recesses on the first and second end faces face each other, and the protrusions face each other. As a result, of the grout material filled in the gap between the first and second end faces, the grout material filled in the pair of central row shear cotters forms vertically extending columns, resulting in a precast concrete foundation with high resistance to horizontal shear forces and torsion. Furthermore, the grout material filled in the pair of central row shear cotters and the pair of left and right rows of shear cotters also provides a precast concrete foundation with high resistance to vertical shear forces.

[0016] Furthermore, since each of the pair of central rows of shear cotters is formed with multiple recesses, the gap between the pair of central rows of shear cotters becomes a filling port for the grout material, and since shear cotters are also formed in this filling port, there is no risk of a significant local decrease in shear strength in the area of ​​the filling port.

[0017] Here, pyramidal convex portions include triangular, quadrangular, and pentagonal or higher-sided pyramids. Furthermore, truncated pyramidal convex portions are those in which the tip of a pyramid such as a triangular or quadrangular pyramid is cut off to have a flat tip surface.

[0018] Another aspect of the precast concrete foundation according to the present invention is A precast concrete foundation for supporting a superstructure of a building, which is formed by a plurality of precast concrete foundation blocks, in which a first end face of one adjacent concrete foundation block faces a second end face of the other adjacent concrete foundation block with a gap therebetween, and the gap is filled with grout material; Both the first end surface and the second end surface are provided with three or more rows of shear cotters in the vertical direction, The central shear cotter has one or more rows of pyramidal or truncated pyramidal recesses that run vertically. The left and right rows of shear cotters have a series of pyramidal or truncated pyramidal convex portions running vertically. The recesses of the first end face and the second end face face each other, and the protrusions of the first end face and the second end face face each other.

[0019] According to this aspect, three or more vertical rows of shear cotters are provided on the first end face of one adjacent concrete foundation block and the second end face of the other adjacent concrete foundation block. The central row or rows of shear cotters have vertically continuous pyramidal or truncated pyramidal recesses, and the left and right rows of shear cotters have vertically continuous pyramidal or truncated pyramidal protrusions. The recesses on the first and second end faces face each other, and the protrusions face each other. Therefore, the grout material filled in the gap between the first and second end faces, the grout material filled in the central row or rows of shear cotters, forms vertically extending columns, resulting in a precast concrete foundation with high resistance to lateral shear and torsional forces. Furthermore, the grout material filled in the central row or rows of shear cotters and the left and right rows of shear cotters provides a precast concrete foundation with high resistance to longitudinal shear forces.

[0020] Furthermore, since the one or more rows of shear cotters on the central side of the pair are each formed with multiple recesses, the gap between the shear cotters in these central rows becomes the filling port for the grout material, and since shear cotters are also formed in this filling port, there is no risk of a significant local decrease in shear strength in the area of ​​the filling port.

[0021] Here, the pyramidal recesses include triangular pyramids, square pyramids, and pyramids with five or more sides. Furthermore, the truncated pyramidal recesses are those in which the tip of a pyramid such as a triangular pyramid or a square pyramid is cut off to have a flat bottom.

[0022] Another aspect of the precast concrete foundation according to the present invention is the pyramidal convex or concave portion is a quadrangular pyramid, The truncated pyramidal convex or concave portion is a truncated square pyramid.

[0023] According to this aspect, since the pyramidal convex or concave portions are square pyramids and the truncated pyramidal convex or concave portions are truncated square pyramids, the grout material filled in the gaps can flow smoothly in both the vertical and horizontal directions, resulting in excellent grout filling properties and allowing the formation of a precast concrete foundation in which the grout material is densely filled into the pyramidal or truncated pyramidal convex or concave portions. [Effects of the Invention]

[0024] As can be understood from the above explanation, the precast concrete foundation of the present invention can provide a precast concrete foundation that has high shear strength in both the vertical and horizontal directions at the joints of the concrete foundation blocks, and that does not have the risk of localized reduction in shear strength in the area of ​​the grout filling port. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a side view of an example of a precast concrete foundation according to an embodiment. [Figure 2] This is a view taken along the arrows II-II in Figure 1, and is a front view of an example of the first end face and second end face of a concrete foundation block, with the grout material filled in the gaps omitted. [Figure 3] 3 is a view taken in the direction of the arrow III in FIG. 1, and is a plan view of an example of a joint between two concrete foundation blocks as seen from above. [Figure 4] 4 is a view taken along the line IV-IV in FIG. 3, and is a vertical cross-sectional view of an example of a joint between two concrete foundation blocks cut inside the outer frame. FIG. [Figure 5]This is a figure corresponding to Figure 2 and is a front view of another example of the first end face and second end face of a concrete foundation block, with the grout material filled in the gaps omitted. [Figure 6] This is a plan view of another example of a joint between two concrete foundation blocks. [Figure 7] This figure corresponds to Figures 2 and 6 and is a front view of yet another example of the first end face and second end face of a concrete foundation block, with the grout material filled in the gaps omitted. [Figure 8] This is a plan view of yet another example of a joint between two concrete foundation blocks. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, an example of a precast concrete foundation according to an embodiment will be described with reference to the accompanying drawings. In this specification and drawings, substantially identical components will be designated by the same reference numerals, and redundant explanations may be omitted.

[0027] [Precast concrete foundation according to the embodiment] An example of a precast concrete foundation according to an embodiment will be described with reference to Figs. 1 to 8. Fig. 1 is a side view of an example of a precast concrete foundation according to an embodiment. Fig. 2 is a view taken along arrows II-II in Fig. 1, showing an example of a first end face and a second end face of a concrete foundation block, with the grout filling the gaps omitted. Fig. 3 is a view taken along arrow III in Fig. 1, showing an example of a joint between two concrete foundation blocks as viewed from above. Fig. 4 is a view taken along arrows IV-IV in Fig. 3, showing a vertical cross-sectional view of an example of a joint between two concrete foundation blocks cut inside the outer frame.

[0028] The concrete foundation block 10 shown in the figure is a precast foundation block that forms the rising portion of the foundation, and is manufactured in a factory and transported to the site to form a foundation such as a strip footing. As shown in Figure 1, the concrete foundation block 10 has a plurality of upper and lower end bars (not shown) that extend in the extension direction of the foundation, a plurality of stirrups (not shown) that connect the upper and lower end bars in the vertical direction and are arranged at a predetermined pitch in the extension direction, and a plurality of web bars (not shown) that are located between the upper and lower end bars and extend in the extension direction.

[0029] A plurality of concrete foundation blocks 10 are transported to the site and arranged, for example, in the extension direction of the foundation along the exterior wall of a building, and grout material 50 is filled into the gaps G between the first end faces 12 and second end faces 13 of adjacent concrete foundation blocks 10 to form joints 60, thereby forming a precast concrete foundation 100 that will serve as the rising part of, for example, a strip footing. Reinforced concrete footings 70, shown by dashed lines, are constructed on site so as to be integrated with the bottom ends 11 of each concrete foundation block 10 that form the precast concrete foundation 100, thereby forming a foundation such as a strip footing.

[0030] Each of the first end face 12 and the second end face 13 of the concrete foundation block 10 shown in FIG. 2 is provided with three rows of shear cotters 22, 32 in the vertical direction.

[0031] More specifically, three rows are provided inside the outer frame 15: a central row 20 and two left and right rows 30. The shear cotters 22 in the central row 20 have horizontally extending recessed portions that are continuous vertically. On the other hand, the shear cotters 32 in the left and right rows 30 have horizontally extending protruding portions that are continuous vertically.

[0032] As shown in Figures 3 and 4, the recesses 22 on both the first end face 12 and the second end face 13 face each other, and the protrusions 32 on both the first end face 12 and the second end face 13 face each other, and grout material 50 is filled in the gap G between the first end face 12 and the second end face 13.

[0033] As shown in Figure 2, horizontally extending recesses 22 are provided continuously in the vertical direction in the central rows 20 of the first end face 12 and the second end face 13, so that a grout filling port with a large planar dimension is formed between the two central rows 20, as shown in Figure 3.

[0034] As a result, as shown in Figure 2, the grout material 50 can be smoothly filled in the vertical direction X1 through the filling port between the two central rows 20, and during the filling process in this X1 direction, the grout material 50 can be diverted to the left and right horizontal directions X2, allowing the grout material to be smoothly filled into the left and right rows 30 as well.

[0035] Furthermore, since a shear cotter extending laterally is formed at the filling port of the grout material 50, there is no risk of a significant local decrease in the shear strength of the joint 60 in the area of ​​the filling port.

[0036] Furthermore, as shown in FIG. 3, a columnar grout material 50A having a large planar dimension is formed at the center of the joint 60, resulting in the joint 60 having high resistance to lateral shear force S2 and torsion.

[0037] Furthermore, as shown in Figure 4, in both the opposing first end face 12 and second end face 13, the horizontally extending convex portions 32 in the left and right rows 30 face each other continuously in the vertical direction, and in the central row 20, the horizontally extending concave portions 22 face each other continuously in the vertical direction, as described above, and grout material 50 is filled between them, resulting in a joint 60 with high resistance to vertical shear force S1.

[0038] In this way, the precast concrete foundation 100 has high shear strength in both the vertical and horizontal directions at the joints 60 of multiple concrete foundation blocks 10 arranged in the extension direction, and is a precast concrete foundation that is not prone to localized reduction in shear strength in the area of ​​the grout material 50 filling port.

[0039] Next, another example of the joint between two concrete foundation blocks will be described with reference to Figures 5 and 6. Here, Figure 5 corresponds to Figure 2 and is a front view of another example of the first end face and second end face of the concrete foundation block, with the grout filling the gaps omitted, and Figure 6 is a plan view of the other example of the joint between two concrete foundation blocks as seen from above.

[0040] At the joint 60A between the two concrete foundation blocks 10 shown in the figure, three rows of shear cotters 24, 34 are provided vertically inside the outer frame 15 on both the first end face 12 and the second end face 13 of each block. Note that, in the joint 60A of the other example shown in the figures, the vertical cross section when viewed from the arrows IV-IV in Figure 6, which is the same as Figure 3, is the same as Figure 4, and therefore, by replacing the reference numeral 32 in Figure 4 with 34, it can be used as the vertical cross section of this example.

[0041] More specifically, the shear cotters 24 in the central row 20 have horizontally extending recesses that are continuous in the vertical direction, resulting in recesses that are longer in the horizontal direction than the recesses in the central row 20 shown in Figure 2. On the other hand, the shear cotters 34 in the left and right rows 30 have truncated pyramidal protrusions that are continuous in the vertical direction.

[0042] Here, the truncated pyramidal convex portion 34 in the illustrated example is a truncated square pyramid, but other than the illustrated example, it may be a truncated triangular pyramid, a truncated pentagonal pyramid, a truncated hexagonal pyramid, etc., or a pyramidal convex portion such as a square pyramid, a pentagonal pyramid, or a hexagonal pyramid may also be applied.

[0043] As shown in Figure 6, the recesses 24 on both the first end face 12 and the second end face 13 face each other, and the protrusions 34 on both the first end face 12 and the second end face 13 face each other, and grout material 50 is filled in the gap G between the first end face 12 and the second end face 13.

[0044] As a result, as shown in Figure 5, the grout material 50 can be smoothly filled in the vertical direction X1 through the filling port between the two central rows 20, and during the filling process in this X1 direction, the grout material 50 can be diverted to the left and right horizontal directions X2, allowing the grout material to be smoothly filled into the left and right rows 30 as well.

[0045] Furthermore, since a shear cotter extending laterally is formed at the filling port of the grout material 50, there is no risk of a significant local decrease in the shear strength of the joint 60 in the area of ​​the filling port.

[0046] Furthermore, as shown in FIG. 6, a columnar grout material 50B having a large planar dimension is formed at the center of the joint 60A, which results in the joint 60A having high resistance to lateral shear force S2 and torsion.

[0047] Furthermore, as shown in Figure 4 (here, as described above, reference numeral 32 in Figure 4 is read as 34), the opposing first end face 12 and second end face 13 have truncated pyramidal convex portions 34 that face each other continuously in the vertical direction in the left and right rows 30, and in the central row 20 have horizontally extending concave portions 24 that face each other continuously in the vertical direction as described above, and grout material 50 is filled between them, resulting in a joint 60A with high resistance to vertical shear force S1.

[0048] In this way, even in a precast concrete foundation 100 equipped with a joint 60A, the joints 60A of multiple concrete foundation blocks 10 arranged in the extension direction have high shear strength in both the vertical and horizontal directions, resulting in a precast concrete foundation in which there is no risk of localized reduction in shear strength in the area of ​​the grout material 50 filling port.

[0049] Next, another example of the joint between two concrete foundation blocks will be described with reference to Figures 7 and 8. Here, Figure 7 corresponds to Figures 2 and 6 and is a front view of another example of the first end face and second end face of a concrete foundation block, with the grout filling the gaps omitted, and Figure 8 is a plan view of another example of the joint between two concrete foundation blocks as seen from above.

[0050] In the joint 60B of the two concrete foundation blocks 10 shown in the figure, three or more rows (four rows in the illustrated example) of shear cotters 26, 34 are provided vertically inside the outer frame 15 on both the first end face 12 and the second end face 13 of each block. Note that in the joint 60B of another example shown in the figure, the vertical cross section when viewed in the direction of arrows IV-IV in Figure 8, which is the same as Figure 3, is the same as Figure 4, and therefore, by replacing the reference numeral 32 in Figure 4 with 34, it can be used as the vertical cross section of this example.

[0051] More specifically, the shear cotters 26 in the center row 20A of the four rows have truncated pyramidal recesses that are continuous in the vertical direction, while the shear cotters 34 in the left and right rows 30 of the four rows have truncated pyramidal protrusions that are continuous in the vertical direction.

[0052] Here, the truncated pyramidal recess 26 and the truncated pyramidal protrusion 34 in the illustrated example are both truncated square pyramids, but in addition to the illustrated examples, they may also be truncated triangular pyramids or truncated pentagonal pyramids, or pyramidal recesses and protrusions such as square pyramids or pentagonal pyramids may also be used.

[0053] As shown in Figure 8, the recesses 26 on both the first end face 12 and the second end face 13 face each other, and the protrusions 34 on both the first end face 12 and the second end face 13 face each other, and grout material 50 is filled in the gap G between the first end face 12 and the second end face 13.

[0054] As a result, as shown in Figure 7, the grout material 50 can be smoothly filled in the X1 direction through the filling port between the two central sides 20A, and during this filling process in the X1 direction, the grout material 50 can be diverted to the left and right in the X2 direction, allowing the grout material to be smoothly filled in the left and right rows 30 as well.

[0055] Furthermore, since a truncated pyramidal recess 26, which is a shear cotter, is formed at the filling port of the grout material 50, there is no risk of a significant local decrease in the shear strength at the joint 60B in the area of ​​the filling port.

[0056] Furthermore, as shown in FIG. 8, columnar grout material 50C having a large planar dimension is formed at the center of joint 60B, resulting in joint 60B with high resistance to lateral shear force S2 and torsion.

[0057] Furthermore, as shown in Figure 4 (here, as described above, reference numeral 32 in Figure 4 is read as 34), the opposing first end face 12 and second end face 13 have truncated pyramidal protrusions 34 that face each other continuously in the vertical direction in the left and right rows 30, and at the center side 20A thereof, as described above, truncated pyramidal recesses 26 that face each other continuously in the vertical direction, and grout material 50 is filled between them, resulting in a joint 60B with high resistance to vertical shear force S1.

[0058] In this way, even in a precast concrete foundation 100 equipped with a joint 60B, the joints 60B of multiple concrete foundation blocks 10 arranged in the extension direction have high shear strength in both the vertical and horizontal directions, resulting in a precast concrete foundation in which there is no risk of localized reduction in shear strength in the area of ​​the grout material 50 filling port.

[0059] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0060] 10: Concrete foundation blocks 11: Bottom edge 12: First end surface (end surface) 13: Second end face (end face) 14: Side 15: Outer frame 16: Hole wall 20: Center row 22, 24: Recess (laterally extending recess, shear cotter) 26: Concave (frustum pyramidal concave, shear cotter) 30: Left and right columns 32: Convex part (convex part extending horizontally, shear cotter) 34: Convex part (frustum pyramidal convex part, shear cotter) 50:Grout material 50A, 50B, 50C: Columnar grout material 60,60A,60B:Joint part 70: Footing (on-site construction footing) 100: Precast concrete foundation G: Gap S1: longitudinal shear force S2: Lateral shear force

Claims

1. A precast concrete foundation for supporting a superstructure of a building, the precast concrete foundation being formed by a plurality of precast concrete foundation blocks, wherein a first end face of one adjacent concrete foundation block faces a second end face of the other adjacent concrete foundation block with a gap therebetween, and the gap is filled with grout material; Both the first end surface and the second end surface are provided with three rows of shear cotters in the vertical direction, The shear cotter in the center row has horizontally extending recesses that are continuous vertically, The left and right rows of shear cotters have horizontally extending convex portions that are continuous vertically. A precast concrete foundation, characterized in that the concave portions of the first end surface and the second end surface face each other, and the convex portions of the first end surface and the second end surface face each other.

2. A precast concrete foundation for supporting a superstructure of a building, the precast concrete foundation being formed by a plurality of precast concrete foundation blocks, wherein a first end face of one adjacent concrete foundation block faces a second end face of the other adjacent concrete foundation block with a gap therebetween, and the gap is filled with grout material; Both the first end surface and the second end surface are provided with three rows of shear cotters in the vertical direction, The shear cotter in the center row has horizontally extending recesses that are continuous vertically, The left and right rows of shear cotters have a series of pyramidal or truncated pyramidal convex portions running vertically. A precast concrete foundation, characterized in that the concave portions of the first end surface and the second end surface face each other, and the convex portions of the first end surface and the second end surface face each other.

3. A precast concrete foundation for supporting a superstructure of a building, the precast concrete foundation being formed by a plurality of precast concrete foundation blocks, wherein a first end face of one adjacent concrete foundation block faces a second end face of the other adjacent concrete foundation block with a gap therebetween, and the gap is filled with grout material; Both the first end surface and the second end surface are provided with three or more rows of shear cotters in the vertical direction, The central row or rows of shear cotters have continuous pyramidal or truncated pyramidal recesses in the vertical direction. The left and right rows of shear cotters have a series of pyramidal or truncated pyramidal convex portions running vertically. A precast concrete foundation, characterized in that the concave portions of the first end surface and the second end surface face each other, and the convex portions of the first end surface and the second end surface face each other.

4. the pyramidal convex or concave portion is a quadrangular pyramid, 4. The precast concrete foundation according to claim 2 or 3, wherein the truncated pyramidal convex or concave portion is a truncated square pyramid.

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