Method for erecting inverted support and inverted support pile

Abstract

To provide an erection method of an inverted support capable of accurately erecting the inverted support in a cast-in-place concrete pile, and the inverted support pile.SOLUTION: A method of erecting an inverted support having a step of placing a first concrete 7 in a pile hole 5, a step of placing a second concrete 10 having a higher fluidity than the first concrete 7 in the pile hole 5, and a step of inserting the inverted support 3 into the second concrete 10 so that a lower end 3a thereof is positioned inside the second concrete 10; and a cast-in-place concrete pile provided with a first concrete portion formed of the first concrete 7 and a second concrete portion formed of the second concrete 10 having a higher fluidity than the first concrete 7; And an inverted support 3 embedded in the second concrete part so that a lower end 3a is positioned inside the second concrete part and supported by the cast-in-place concrete pile.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a method for erecting an inverted support pillar and an inverted support pile. [Background technology]

[0002] The inverted construction method is known as a construction method for constructing buildings with above-ground and underground portions. With this method, before excavating the ground to construct the underground frame, inverted-casting supports for supporting the above-ground portion of the building are erected in pile holes drilled in the ground. This allows the above-ground portion to be constructed using the inverted-casting supports while the ground is excavated and the underground frame is constructed. This shortens the construction period for buildings compared to construction methods in which the above-ground portion is constructed after the underground portion is completed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-6744 Summary of the Invention [Problem to be solved by the invention]

[0004] In this type of inverted construction method, a known method for erecting an inverted support post into a pile hole involves pouring concrete into a pile hole in the ground, inserting the root portion of the inverted support post into the concrete, and allowing the concrete to harden in this state, thereby fixing the inverted support post to the cast-in-place concrete pile.

[0005] However, with the post-setting method, when adjusting the position of the inverted support inserted into the concrete poured into the pile hole, the inverted support is subjected to resistance from the concrete, making it difficult to adjust the position of the inverted support, and making it difficult to accurately install the inverted support into the cast-in-place concrete pile.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a method for installing an inverted support pillar and an inverted support pillar that can be installed accurately into a cast-in-place concrete pile. [Means for solving the problem]

[0007] The method for erecting an inverted support pillar of the present invention is characterized by comprising the steps of: pouring a first concrete into a pile hole provided in the ground; after pouring the first concrete, pouring a second concrete having higher fluidity than the first concrete into the pile hole; and after pouring the second concrete, inserting the inverted support pillar into the second concrete so that its lower end is positioned inside the second concrete.

[0008] In the above-mentioned configuration, the method for erecting a reverse-cast support pillar of the present invention preferably further includes a step of removing defective concrete from above the first concrete after pouring the first concrete and before pouring the second concrete.

[0009] In the method for erecting a reverse-cast support pillar of the present invention, in the above configuration, it is preferable to use a casing that covers the inner surface of the pile hole when pouring the first concrete and the second concrete, in order to protect the pile hole wall when the ground is weak and to protect the hole wall during concrete joint processing work.

[0010] The inverted support pile of the present invention is characterized by having a cast-in-place concrete pile having a first concrete portion formed from a first concrete and a second concrete portion formed from a second concrete having higher fluidity than the first concrete and poured on top of the first concrete portion, and an inverted support pillar embedded in the second concrete portion so that its lower end is located inside the second concrete portion and supported by the cast-in-place concrete pile. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a method for installing an inverted support pillar and an inverted support pillar that can accurately install an inverted support pillar into a cast-in-place concrete pile. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a reverse-driven support pile according to one embodiment of the present invention. [Figure 2] 1 is a diagram showing a pile hole into which a reverse-driven support is erected by a method for erecting a reverse-driven support according to one embodiment of the present invention. FIG. [Figure 3] FIG. 10 is a diagram showing the state in which the first concrete is being poured into the pile hole. [Figure 4] FIG. 10 is a diagram showing a pile hole after the pouring of the first concrete has been completed. [Figure 5] FIG. 10 is a diagram showing the removal of defective concrete above the first concrete. [Figure 6] FIG. 10 is a diagram showing a pile hole after the casting of the second concrete has been completed. [Figure 7] FIG. 10 is a diagram showing the removal of defective concrete above the second concrete. [Figure 8] This is a diagram showing the state in which a reverse-cast support is inserted into the second concrete. [Figure 9] FIG. 10 is a diagram showing a modified example of a reverse-driven support pile. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, a method for erecting an inverted support and an inverted support pile according to one embodiment of the present invention will be described in detail with reference to the drawings.

[0014] The inverted support pile 1 according to one embodiment of the present invention shown in Figure 1 is formed by a method for erecting an inverted support pile according to one embodiment of the present invention when constructing a building (not shown) having an above-ground portion and an underground portion using the inverted construction method.

[0015] The inverted support pile 1 has a cast-in-place concrete pile 2 and an inverted support 3.

[0016] The cast-in-place concrete pile 2 is for supporting the inverted support column 3, and is formed by pouring concrete into a pile hole 5 provided in the ground 4 at the construction site of the building.

[0017] The pile hole 5 is formed by excavating the ground 4 at the planned position for erecting the inverted support 3 to a predetermined depth using an excavation device such as a drill.

[0018] The cast-in-place concrete pile 2 comprises a first concrete portion 2a formed from a first concrete, and a second concrete portion 2b formed from a second concrete having higher fluidity than the first concrete and poured onto the first concrete portion 2a. The first concrete portion 2a is formed into a pile shape by the first concrete poured into a pile hole 5 and hardening inside the pile hole 5. The second concrete portion 2b is formed into a pile shape that is integrally connected to the first concrete portion 2a by the second concrete poured into the pile hole 5 on top of the first concrete and hardening inside the pile hole 5. Because the second concrete that forms the second concrete portion 2b has higher fluidity than the first concrete that forms the first concrete portion 2a, the nominal strength of the second concrete portion 2b is equal to or greater than the nominal strength of the first concrete portion 2a.

[0019] In this embodiment, the first concrete forming the first concrete portion 2a is so-called ordinary concrete. Ordinary concrete has a required slump of 5 cm to 21 cm. In this embodiment, the first concrete used has a required slump of 21 cm.

[0020] In contrast, in this embodiment, the second concrete forming the second concrete portion 2b is so-called high-fluidity concrete, which has higher fluidity than ordinary concrete. High-fluidity concrete has a required slump flow of 45 cm to 60 cm. In this embodiment, the second concrete used has a required slump flow of 50 cm.

[0021] In addition, the first concrete forming the first concrete portion 2a and the second concrete forming the second concrete portion 2b can be made of various types of concrete, not just the ordinary concrete and high-fluidity concrete described above, as long as the second concrete has a higher fluidity than the first concrete.

[0022] The inverted support pillar 3 is a straight pillar of a predetermined length. In this embodiment, the inverted support pillar 3 is formed of a cross-H shaped steel frame. Note that the inverted support pillar 3 is not limited to a cross-H shaped steel frame, and may be formed of steel frames of other shapes, such as a box shape or an H shape formed from a steel pipe with a rectangular cross section.

[0023] The inverted support pillar 3 is embedded in the second concrete section 2b so that its lower end 3a is located inside the second concrete section 2b, and is supported by the cast-in-place concrete pile 2. More specifically, the inverted support pillar 3 is in an upright position with its longitudinal axis O parallel to the vertical, and its embedded portion 3b, which extends upward from its lower end 3a and is a predetermined range, is embedded in the second concrete section 2b, and is supported by the axis of the cast-in-place concrete pile 2 so that the portion above the embedded portion 3b protrudes upward from the second concrete section 2b. In other words, the inverted support pillar 3 is disposed only inside the second concrete section 2b, and not inside the first concrete section 2a.

[0024] The inverted support 3 may be configured to have increased fixing strength to the second concrete section 2b by fixing multiple headed studs (not shown) that protrude toward the inside of the second concrete section 2b to the embedded section 3b.

[0025] When constructing an underground skeleton of a building by the inverted construction method, the inverted support pile 1 having the above-mentioned configuration is used as a column constituting the underground skeleton, with the inverted support 3 being used as a column constituting the underground skeleton.

[0026] Next, we will explain the method for erecting an inverted support pillar 3 using a post-setting method in a pile hole 5 created in the ground 4, i.e., the procedure for forming an inverted support pillar 1 of the above-mentioned configuration, using a method for erecting an inverted support pillar 3 according to one embodiment of the present invention.

[0027] First, as shown in Figure 2, at a construction site where a building is to be constructed, a drill or other excavation device is used to excavate the ground 4 at a planned location for erecting a cast-in-place support 3 to a predetermined depth to form a pile hole 5. Then, a cylindrical steel casing 6 is installed inside the pile hole 5 so as to cover the inner circumferential surface of the joint between the first concrete section 2a and the second concrete section 2b and the section where the second concrete section 2b will be formed. Note that the installation of the casing 6 is not required.

[0028] Next, as shown in Figures 3 and 4, a first concrete 7 is poured into a pile hole 5 provided in the ground 4. Specifically, as shown in Figure 3, a tremie pipe 8 is erected inside the pile hole 5, and the first concrete 7 is poured into the pile hole 5 from the opening of the lower end 8a of the tremie pipe 8, and the first concrete 7 is poured up to a predetermined level as shown in Figure 4. The first concrete 7 is poured by inserting the lower end 8a of the tremie pipe 8 into the first concrete 7 and moving the tremie pipe 8 upward as the level of the first concrete 7 rises. In this embodiment, the first concrete 7 is poured until the upper end of the first concrete 7 reaches a level (height) that reaches the casing 6.

[0029] The first concrete 7 poured into the pile hole 5 in this step is so-called ordinary concrete with a required slump of 5 cm to 21 cm. In this embodiment, the first concrete 7 is ordinary concrete with a required slump of 21 cm. Note that the first concrete 7 is not limited to the ordinary concrete described above, and various types of concrete can be used as long as they have lower fluidity than the second concrete 10 described below.

[0030] As shown in Figure 4, when the pouring of the first concrete 7 is completed, defective concrete 7a may be generated above the first concrete 7 due to exposure of coarse aggregate, etc. In this case, a step of removing the defective concrete 7a above the first concrete 7 may be carried out after pouring the first concrete 7. Specifically, as shown in Figure 5, after pouring the first concrete 7, a suction pipe 9 may be erected into the pile hole 5, and the defective concrete 7a may be sucked out and removed by the suction pipe 9. At this time, the casing 6 is moved so that its lower end is positioned slightly below the defective concrete 7a.

[0031] After the first concrete 7 is poured into the pile hole 5, a second concrete 10 having higher fluidity than the first concrete 7 is poured into the pile hole 5, as shown in FIG. 6 . More specifically, the tremie pipe 8 is again erected inside the pile hole 5, and the second concrete 10 is poured into the pile hole 5 from the opening of the lower end 8a of the tremie pipe 8, and then the second concrete 10 is poured on top of the first concrete 7 up to a predetermined level. As in the case of pouring the first concrete 7, the second concrete 10 is poured by inserting the lower end 8a of the tremie pipe 8 into the second concrete 10 and moving the tremie pipe 8 upward as the level of the second concrete 10 rises. In this embodiment, the second concrete 10 is poured until the upper end of the second concrete 10 is within the range of the casing 6.

[0032] The second concrete 10 poured into the pile hole 5 in this step is so-called high-fluidity concrete with a required slump flow of 45 cm to 60 cm. In this embodiment, the second concrete 10 is high-fluidity concrete with a required slump flow of 50 cm. Note that the second concrete 10 is not limited to the high-fluidity concrete described above, and various types of concrete can be used as long as they have higher fluidity than the first concrete 7.

[0033] As shown in FIG. 6, when the pouring of the second concrete 10 is completed, defective concrete 10a may be formed on top of the second concrete 10 due to exposure of coarse aggregate. In this case, a step of removing the defective concrete 10a on top of the second concrete 10 may be performed after pouring the second concrete 10. Specifically, as shown in FIG. 7, after pouring the second concrete 10, a suction pipe 9 may be inserted into the pile hole 5, and the defective concrete 10a may be sucked and removed using the suction pipe 9. At this time, the casing 6 is moved so that its lower end is positioned slightly below the defective concrete 10a. Note that the defective concrete 10a may be removed by chipping it off after the second concrete 10 and the defective concrete 10a have hardened, without performing the removal step using the suction pipe 9.

[0034] After the second concrete 10 is poured into the pile hole 5, the inverted-casting support 3 is inserted into the second concrete 10 so that its lower end 3a is positioned inside the second concrete 10, as shown in FIG. 8 . The inverted-casting support 3 is inserted into the second concrete 10 before the second concrete 10 hardens. More specifically, the inverted-casting support 3 is in an upright position with its longitudinal axis O parallel to the vertical, and its embedded portion 3b, which extends upward from its lower end 3a, is positioned inside the second concrete 10. The inverted-casting support 3 is inserted along the axis of the second concrete 10 so that the portion above the embedded portion 3b protrudes upward from the second concrete 10. In other words, the inverted-casting support 3 is inserted into the second concrete 10 until its lower end 3a is positioned inside the second concrete 10, but its lower end 3a does not reach the first concrete 7. Note that the casing 6 is removed from the pile hole 5 before inserting the inverted-casting support 3 into the second concrete 10.

[0035] After inserting the inverted support post 3 into the second concrete 10 so that its lower end 3a is located inside the second concrete 10, when the first concrete 7 and the second concrete 10 harden, as shown in Figure 1, the inverted support post pile 1 is completed, which includes a cast-in-place concrete pile 2 having a first concrete portion 2a where the first concrete 7 has hardened, and a second concrete portion 2b where the second concrete 10 has hardened and been poured onto the first concrete portion 2a, and an inverted support post 3 embedded in the second concrete portion 2b so that its lower end 3a is located inside the second concrete portion 2b and supported by the cast-in-place concrete pile 2. As a result, the inverted support post 3 is erected in the pile hole 5.

[0036] Here, in the method for setting up a cast-in-place support according to this embodiment, as described above, first concrete 7 is poured into a pile hole 5 provided in the ground 4, and then second concrete 10, which has a higher fluidity than the first concrete 7, is poured into the pile hole 5, and the cast-in-place support 3 is inserted into the second concrete 10 so that its lower end 3a is positioned inside the second concrete 10. Therefore, after inserting the cast-in-place support 3 into the second concrete 10, when the cast-in-place support 3 is moved horizontally or vertically inside the pile hole 5 to adjust its position to a specified position, the cast-in-place support 3 does not encounter significant resistance hindering its movement from the first concrete 7, but only from the second concrete 10, which has a higher fluidity than the first concrete 7. Therefore, according to the method for setting up a cast-in-place support according to this embodiment, the position of the cast-in-place support 3 can be adjusted more easily than when only the first concrete 7 is poured into the pile hole 5 and then the cast-in-place support 3 is inserted into the first concrete 7. This allows the inverted support pillar 3 to be accurately erected into the cast-in-place concrete pile 2, and also allows the inverted support pillar pile 1 to have the inverted support pillar 3 erected into it with high precision.

[0037] Furthermore, the more fluid the concrete, the more expensive it is. However, in the method of installing an inverted support pillar according to this embodiment, the portion of the concrete poured into the pile hole 5 into which the inverted support pillar 3 is not inserted is made of the inexpensive first concrete 7, and only the portion of the concrete into which the inverted support pillar 3 is inserted is made of the second concrete 10, which has a higher fluidity than the first concrete 7. Therefore, compared to when all the concrete poured into the pile hole 5 is made of the second concrete 10, which has a higher fluidity, the cost required to install the inverted support pillar 3 into the pile hole 5 or the cost of the inverted support pillar 1 can be reduced.

[0038] Furthermore, in the method of erecting a cast-in-place support pillar according to this embodiment, after the first concrete 7 is poured into the pile hole 5, the defective concrete 7a on top of the first concrete 7 is removed before the second concrete 10 is poured, thereby enabling the first concrete section 2a and the second concrete section 2b to be joined more firmly at the joint, thereby increasing the strength of the cast-in-place concrete pile 2.

[0039] Furthermore, in the method for erecting a cast-in-place pillar according to this embodiment, the casing 6 is installed on the inner circumferential surface of the joint between the first concrete section 2a and the second concrete section 2b of the pile hole 5 and the section where the second concrete section 2b is formed, which makes it possible to prevent gravel and sand on the inner circumferential surface of the pile hole 5 from mixing into the joint between the first concrete section 2a and the second concrete section 2b and to prevent the joint from being affected by water. This makes it possible to prevent poor jointing at the joint between the first concrete section 2a and the second concrete section 2b.

[0040] As shown as a modified example in Figure 9, in the method for installing an inverted support pillar or the inverted support pillar pile 1 according to this embodiment, the pile hole 5 may be in a stepped shape having a large diameter portion 5a that opens to the ground 4 and a small diameter portion 5b that is connected below the large diameter portion 5a and has a smaller diameter than the large diameter portion 5a.

[0041] In this modification, it is preferable to pour the first concrete 7 to a level that fills the small diameter portion 5b and reaches the large diameter portion 5a, then remove the defective concrete 7a, and then pour the second concrete 10 into only the large diameter portion 5a on top of the first concrete 7. This reduces the amount of first concrete 7 poured into the pile hole 5 while maintaining the above-mentioned effects, thereby reducing the cost required to erect the inverted support post 3 into the pile hole 5 and the cost of the inverted support post 1.

[0042] Although not shown in detail, in this modified example, when the first concrete 7 and the second concrete 10 are poured into the pile hole 5, it is preferable to install the casing 6 so as to cover the entire inner circumferential surface of the large diameter part 5a of the pile hole 5. This allows the casing 6 to be installed at a specified position with high precision.

[0043] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit and scope of the present invention.

[0044] For example, in the above embodiment, the pile hole 5 is exemplified by one having a constant inner diameter as shown in FIG. 1 and one having a stepped shape with a large diameter portion 5a and a small diameter portion 5b as shown in FIG. 9, but the shape of the pile hole 5 can be changed as appropriate.

[0045] In addition, in the above embodiment, after the pouring of the first concrete 7 is completed, a step is carried out to remove the defective concrete 7a on top of the first concrete 7, but depending on the construction situation, the second concrete 10 may be poured without carrying out the step of removing the defective concrete 7a.

[0046] Furthermore, this method is also useful as a pre-determining method in which the inverted support pillar 3 is erected before the first concrete 7 and the second concrete 10 are poured, as it improves the workability of concrete work on the cast-in-place concrete pile 2 and makes it easier to check the accuracy of the inverted support pillar 3. [Explanation of symbols]

[0047] 1. Reverse-driven support piles 2. Cast-in-place concrete piles 2a First concrete section 2b Second concrete section 3. Reverse-driven support 3a bottom edge 3b Root section 4 Ground 5. Pileholes 5a Large diameter part 5b Small diameter section 6 Casing 7. First Concrete 7a Poor concrete 8 Ptolemie 9 Suction tube 10 Second Concrete 10a Poor concrete O axis

Claims

1. Pouring first concrete into pile holes provided in the ground; After pouring the first concrete, pouring a second concrete having higher fluidity than the first concrete into the pile hole; A method for installing an inverted support, characterized by comprising a step of inserting an inverted support into the second concrete so that its lower end is positioned inside the second concrete after pouring the second concrete.

2. 2. The method for erecting an inverted support pillar as described in claim 1, further comprising the step of removing defective concrete on top of the first concrete after pouring the first concrete and before pouring the second concrete.

3. The method for erecting an inverted support according to claim 1 or 2, wherein a casing covering the inner surface of the pile hole is used when pouring the first concrete and the second concrete.

4. a cast-in-place concrete pile comprising: a first concrete portion formed of a first concrete; and a second concrete portion formed of a second concrete having higher fluidity than the first concrete and poured onto the first concrete portion; An inverted support pile characterized by having an inverted support pillar buried in the second concrete section so that its lower end is located inside the second concrete section and supported by the cast-in-place concrete pile.

Images