JP7400557B2 - How to install the main leg of a deep foundation - Google Patents

Description

The present invention relates to a method for installing main leg members of a deep foundation, in which the main leg members constituting the legs of a structure such as a steel tower are installed on a deep foundation.

Generally, the legs of huge structures such as power transmission towers located in mountainous areas are supported by deep foundations (for example, Patent Document 1). When installing the legs of a structure on a deep foundation, first excavate underground to form an excavated hole, and then extend the hole until it reaches a position near the lower end of the main leg material that makes up the legs. Concrete is poured in (first time). After the main leg material is installed on the concrete poured in the first step, concrete is further poured up to the upper end of the excavation hole (second time). This forms a deep foundation. After that, a formwork is installed around the main leg material and concrete is poured there (third time), so that the structure's legs are installed on the deep foundation.

Patent No. 3745027

As described above, in the conventional method, when forming a deep foundation, concrete is poured twice in the frame part, before and after placing the main leg members. For this reason, it is necessary to install reinforcement bars to connect the concrete before and after the placement of the main leg members. Concrete is too soft immediately after pouring, so reinforcement bars can only be installed after the concrete that has been poured has begun to harden to some extent before the main leg members are placed. For this reason, after the first concrete is poured, it is necessary to wait for the concrete to harden before installing the joint reinforcing bars, resulting in a loss of working time. Furthermore, since it is necessary to install the main reinforcing bars twice, it is not only the work that is required twice, but also the lap length of the main reinforcing bars.

Furthermore, when concrete is poured twice, laitance treatment is required to remove impurities from the surface of the concrete poured the first time in order to ensure the quality of the concrete. Furthermore, when installing the main landing gear, it is necessary to install blocks for fixing the main landing gear on top of the first cast concrete. However, this process can only be carried out after the first concrete has hardened to a certain extent, resulting in a loss of working time.

In addition, if concrete is poured twice, a curing period is naturally required for the first concrete. In addition, since the concrete pouring work will be done twice (because the deep foundation framework is poured in parts), work before and after the pouring work, such as preparing materials and equipment for concrete pouring, cleaning, and tidying up, will also be required. Must be done twice. For this reason, the number of days that concrete pump trucks, piping, buckets, chutes, vibrators, etc. are in service increases, and the work such as cleaning increases, resulting in an increase in costs such as labor costs and material costs.

Furthermore, a column body part on which the main leg member of the steel tower is fixed is formed on the upper part of the deep foundation. Since this column body is also an RC structure, it is necessary to insert anchoring reinforcing bars into the interior of the frame. However, the inside of the excavation hole is extremely narrow and there is no space for construction of scaffolding, etc., so the work must be carried out with the anchorage reinforcing bars suspended in the air. It is difficult to install heavy anchoring reinforcing bars by vertical work, and there is a problem that workability and efficiency are poor.

In view of these problems, the present invention can simplify the work process when installing the main leg materials that make up the legs of a structure on a deep foundation, and can significantly reduce the time, cost, and labor required for the work. The purpose of the present invention is to provide a method for installing main leg members for deep foundations that can reduce the number of times.

In order to solve the above problems, a typical configuration of the main leg member installation method for a deep foundation according to the present invention is to install a support on the wall surface of an excavation hole, and install a support from one wall surface near the opening of the excavation hole. Attach two beams that span opposing walls, and with the beams supporting the steel pipe that will become the column, concrete is poured into the frame and the steel pipe at once, and the main leg material is placed at the top of the steel pipe. It is characterized by being fixed.

According to the above configuration, concrete for the frame can be poured in one step. Therefore, it is possible to simplify the work process when installing the main leg members that constitute the legs of the structure on the deep foundation, and it is possible to significantly reduce the time, cost, and labor required for the work. In particular, in the above configuration, the steel pipe serving as the column body portion is supported by the beam member, and the main leg member is fixed to the upper end of the steel pipe. As a result, the main leg member is supported by the steel pipe in a stable state, making it possible to efficiently fix the main leg member to the deep foundation.

The beam material is preferably placed above the concrete pouring surface of the frame. According to this configuration, the beams are not buried in the concrete of the frame, so the beams can be reused. Therefore, it is possible to reduce member costs.

The above-mentioned beam material is installed in the excavation hole toward the center of the steel tower, and a tab is attached to the side of the steel pipe to be placed on the beam material. It is preferable that the position of the steel pipe be adjustable by supporting the steel pipe with the beam and moving the steel pipe along the beam with the tab resting on the beam. Thereby, by placing the tab on the beam, the beam can support the steel pipe more reliably. Moreover, according to this configuration, by moving the tab along the beam material, the position of the steel pipe within the excavation hole can be easily adjusted.

The tab is preferably removable from the steel pipe. Thereby, the tab can be reused by removing the tab after pouring concrete and fixing the steel pipe to the frame. Therefore, it is possible to reduce member costs.

It is preferable that a reinforcing bar for fixing is attached to the lower end of the steel pipe. By using reinforcing bars for anchoring in this way, it is possible to reduce the weight compared to the case where the entire structure is made of steel pipes and to facilitate transportation to mountainous areas.

After pouring concrete into the above-mentioned main body and steel pipes, screw holes are made in multiple directions in the steel pipes at a position above the concrete pouring surface in the steel pipes, and bolts are installed in each of the screw holes. It is best to fix the main landing gear after adjusting the position. According to this configuration, the position of the main leg member can be easily adjusted using the screw holes and bolts provided in the steel pipe.

According to the present invention, it is possible to simplify the work process when installing the main leg members that constitute the legs of a structure on a deep foundation, and it is possible to significantly reduce the time, cost, and labor required for the work. It is possible to provide a possible method for installing main leg members of a deep foundation.

It is a figure explaining the main leg material installation method of the deep foundation concerning this embodiment. It is a figure explaining the work process of the main leg material installation method of the deep foundation concerning this embodiment. It is a detailed view of FIG.2(b). FIG. 3 is an enlarged view of the vicinity of the lower end of the steel pipe. It is a figure explaining position adjustment of a main leg member. It is a figure explaining the main leg material installation method of the conventional deep foundation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in these embodiments are merely illustrative to facilitate understanding of the invention, and do not limit the invention unless otherwise specified. In this specification and the drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to omit redundant explanation, and elements not directly related to the present invention are omitted from illustration. do.

FIG. 1 is a diagram illustrating a method for installing main leg members of a deep foundation according to this embodiment. FIG. 2 is a diagram illustrating the work steps of the main leg member installation method for a deep foundation according to the present embodiment. FIG. 6 is a diagram illustrating a conventional method for installing main leg members of a deep foundation. Hereinafter, in order to make it easier to understand the characteristics of the main leg member installation method for deep foundations of this embodiment (hereinafter simply referred to as the installation method), we will first explain the conventional installation method with reference to FIG. The installation method of the embodiment will be explained in detail.

As shown in FIG. 6A, in the conventional installation method, an excavated hole 10 is first formed by excavating underground, and shoring 12 is installed on the wall of the excavated hole 10 each time the excavation is made. Then, the frame reinforcing bars 14 are assembled inside the shoring 12, and as shown in FIG. 6(b), the frame lower concrete 16 (first concrete) is placed.

After the lower frame concrete 16 hardens, a laitance treatment is performed to remove impurities from the concrete pouring surface 16a of the first cast lower frame concrete 16 in order to ensure its quality. Then, as shown in FIG. 6(c), a block 20 is installed on the concrete placement surface 16a, and a main leg member 22 is installed on the block. After the installation is completed, the frame reinforcement bars 14b are assembled.

Thereafter, the column reinforcing bars 24 are assembled around the main leg member 22. At this time, the columnar reinforcing bars 24 are in a suspended state. Then, as shown in FIG. 6(d), concrete 26 (second concrete) for the upper part of the frame is poured. After laitance treatment is applied to the lower surface of the column, a formwork is installed around the column reinforcing bars 24, and column concrete 28 is cast, as shown in FIG. 6(e). As a result, as shown in FIG. 6(f), a deep foundation 30 consisting of two layers of lower frame concrete 16 and upper frame concrete 26 is formed, and the main leg members 22 are installed therein.

As explained above, in the conventional installation method, when forming the deep foundation 30, it is necessary to pour the lower frame concrete 16 and the upper frame concrete 26 twice. Accordingly, it becomes necessary to perform laitance treatment on the concrete casting surface 16a of the concrete lower part of the frame 16 and laitance treatment on the lower surface of the column.

In addition, the concrete pouring work is performed twice in this way, that is, by dividing the deep foundation 30 into parts and pouring it, the work before and after the pouring process, such as preparing materials and equipment for concrete pouring, is performed twice. I will have to. For this reason, the number of days that concrete pump trucks and the like are in service increases, and the work such as cleaning increases, resulting in an increase in costs such as labor costs and material costs.

Therefore, in the installation method of this embodiment, concrete is poured once when forming the deep foundation 30, thereby reducing the work time and cost that would otherwise be required when concrete is poured twice as in the past. This enables a significant reduction. In the following description, the same reference numerals are given to the same components and steps as in the conventional installation method described using FIG. 6, and the description thereof will be omitted.

As shown in FIG. 1, in the installation method of this embodiment, a deep foundation 100 consisting of a frame part 110 and a column part 120 is formed, and the main leg member 22 is installed there. As shown in FIG. 2A, also in the installation method of this embodiment, an excavation hole 10 is first formed, and shoring 12 is installed on the wall surface of the excavation hole 10 each time the excavation hole 10 is dug. Although the shoring 12 is shown in cross section in FIG. 2(a), it is actually an arc-shaped board divided in the circumferential direction, and as the excavation hole 10 is dug from above, It is attached. That is, inside the excavated hole 10, the shoring is installed so as to be connected in the height direction and the circumferential direction. In the frame portion 110, grout (not shown) is filled between the shoring 12 and the underground soil.

In this embodiment, a reinforcing ring 130 is attached between the supports 12 near the opening of the excavated hole 10. For example, it may be installed between the first layer of shoring 12 and the second layer of shoring 12 from the top. The reinforcing ring 130 is an annular member with an H-shaped cross section, and is a member for increasing the rigidity of the support 12 in the vicinity thereof. However, in this embodiment, it is installed for the purpose of attaching a beam member 140, which will be described later. After the excavation hole 10 has been dug, the building frame reinforcing bars 14 are assembled inside it.

Next, as shown in FIG. 2(b), a beam 140 is attached to the reinforcing ring 130, and the steel pipe 150 that will become the column 120 is supported by the beam 140. FIG. 3 is a detailed view of FIG. 2(b). 3(a) is an enlarged view of the beam material 140 and the steel pipe 150 observed from the side, FIG. 3(b) is a view of the excavated hole 10 observed from above, and FIG. 3(c) is It is an enlarged view of the beam material 140.

First, as shown in FIGS. 2(b) and 3(c), two beam members 140 are attached so as to be hooked onto the reinforcing ring 130. Thereby, two beam members 140 are attached near the opening of the excavated hole 10 from one wall surface to the opposing wall surface. Since the shoring 12 is reinforced by the reinforcing ring 130, it can support the beam 140 with high strength. Note that the present invention is not limited to this, and it is also possible to have a configuration in which the beam 140 is directly supported by the shoring 12 without using the reinforcing ring 130.

As shown in FIG. 3(a), a tab 152 that is placed on the beam 140 is attached to the side surface of the steel pipe 150. Thereby, the steel pipe 150 is supported by the beam 140 by placing the tab 152 on the beam 140. Therefore, the steel pipe 150 can be stably supported. Since this steel pipe is designed as a concrete-filled steel pipe column (CFT), there is no need to wrap the main leg material in reinforced concrete, and there is no need to work in a suspended state as in the prior art.

As shown in FIG. 3(b), the beam member 140 is arranged within the excavated hole 10 toward the center of the steel tower. Thereby, by moving the steel pipe along the beam 140 with the tab 152 on top of the beam 140, the horizontal position of the steel pipe 150 relative to the center of the steel tower can be adjusted. For example, as shown by the arrow in FIG. 3(b), by moving the steel pipe 150 in the longitudinal direction of the beam 140, the distance between the steel pipe 150 and the center of the steel tower can be adjusted.

Furthermore, as shown in FIGS. 3(a) and 3(c), the heightwise position of the steel pipe 150 can be adjusted by inserting a bolt 154 into the tab 152 and adjusting the screwing degree of the bolt 154. It becomes possible. The inclination and direction of the steel pipe 150 are adjusted by the support member 40. Once the position of the steel pipe 150 is determined, the tab 152 and the beam member 140 are fixed with fixing bolts 155 as shown in FIG. 3(c).

In the example of FIG. 3A, it is assumed that the tab 152 described above is welded to the steel pipe 150. However, the tab 152 may be detachable from the steel pipe 150 using a bolt or the like. If it is made removable, the tab 152 can be removed and reused after adjusting the position of the steel pipe 150 in the excavated hole 10 and placing the concrete structure 160. Therefore, it is possible to reduce member costs.

FIG. 4 is an enlarged view of the vicinity of the lower end of the steel pipe 150. As shown in FIG. 4, a reinforcing bar 180 for fixing is attached to the lower end of the steel pipe 150. Specifically, a coupler 156 (a long nut-like member) is welded to the side surface of the lower end of the steel pipe 150. On the other hand, threaded reinforcing bars are used for the fixing reinforcing bars 180. Thereby, the reinforcing bar 180 is attached to the steel pipe 150 by screwing the reinforcing bar 180 into the coupler 156 welded to the side surface of the steel pipe 150. A tie bar 182 is spirally wound around a reinforcing bar 180 which is a main bar. By using the anchoring reinforcing bars 180 in this way, it is possible to more firmly anchor the steel pipe 150 to the frame portion 110 while reducing the weight compared to when the entire structure is made of steel pipes. Note that the reinforcing bars 180 may be directly welded to the steel pipe 150.

As shown in FIG. 2(c), once the positioning of the steel pipe 150 is completed, concrete (frame concrete 160 and column concrete 170) is placed inside the frame 110 and the steel pipe 150 in this state. As a result, not only the frame portion 110 but also the middle position of the column portion 120 is poured at once. Since the steel pipe 150 serves as a formwork in the column body portion 120, it is not necessary to construct a formwork. Further, in the column body portion 120, the CFT design is adopted in which the steel pipe 150 restrains the column concrete 170, so there is no need to arrange reinforcement inside.

The beam material 140 is arranged above the concrete casting surface 160a of the concrete frame 160. Thereby, the beam material 140 is not buried in the concrete frame 160, so that the beam material 140 can be reused. Therefore, it is possible to reduce member costs.

After the concrete frame 160 and the concrete column 170 are placed, the beams 140 are removed and backfilling is performed. Next, the main leg member 22 is inserted into the upper end of the steel pipe 150, and the column concrete 172 is further cast.

FIG. 5 is a diagram illustrating position adjustment of the main leg member 22. As shown in FIG. 5A, a plurality of screw holes 150a are previously formed in the steel pipe 150 at positions above the concrete placement surface 170a within the steel pipe 150. In this embodiment, after backfilling is performed as shown in FIG. 2(c) and scaffolding is secured, bolts 158 are attached to each screw hole 150a above the concrete placement surface 170a.

Then, the position of the main leg member 22 within the steel pipe 150 is adjusted by turning the bolt 158 shown in FIG. 5(b) to move it forward or backward. By abutting the three bolts 158 against the main leg member 22 from three directions, the main leg member 22 can be positioned and fixed with respect to the steel pipe 150. After adjusting the position of the main leg member 22, concrete (column concrete 172) is poured to fix the main leg member 22 as shown in FIG. 2(d). As described above, according to the installation method of this embodiment, it is possible to easily adjust the position of the main leg member 22 using the screw hole 150a and the bolt 158 provided in the steel pipe 150.

As explained above, according to the method for installing main leg members of a deep foundation according to the present invention, concrete for the frame part 110 is poured in one time, so compared to the conventional technology, the leg parts of the structure are The work process when installing the constituent main leg members 22 on the deep foundation 100 can be simplified. Therefore, it is possible to significantly reduce the time, cost, and labor required for the work.

Further, a steel pipe 150 that becomes the column body portion 120 is supported by the beam member 140, and the main leg member 22 is fixed to the upper end of the steel pipe 150. Thereby, the steel pipe 150 and the main leg member 22 can be stably supported. Therefore, it is possible to efficiently perform the work of fixing the main leg member 22 to the deep foundation 100 without having to work in a suspended state as in the prior art.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It is clear that those skilled in the art can come up with various changes and modifications within the scope of the claims, and these naturally fall within the technical scope of the present invention. Understood.

INDUSTRIAL APPLICATION This invention can be utilized as the main leg material installation method of the deep foundation which installs the main leg material which comprises the leg part of structures, such as a steel tower, on a deep foundation foundation.

10... Excavation hole, 12... Shoring, 14... Skeleton reinforcing bars, 16... Skeleton lower concrete, 16a... Concrete placement surface, 20... Block, 22... Main leg material, 24... Column body reinforcing bars, 26... Skeleton upper concrete, 28...Column concrete, 30...Deep foundation, 40...Support member, 100...Deep foundation, 110...Structure section, 120...Column body section, 130...Reinforcement ring, 140...Beam material, 150...Steel pipe, 150a... Screw hole, 152...Tab, 154...Bolt, 155...Fixing bolt, 156...Coupler, 158...Bolt, 160...Structure concrete, 160a...Concrete casting surface, 170...Column concrete, 172...Column concrete, 180... Reinforcing bar, 182...Stirling bar

Claims (6)

Install shoring on the wall of the excavation hole,
Two beams are installed near the opening of the excavation hole, spanning from one wall to the opposite wall.
With the beam material supporting the steel pipe that will become the column part,
Concrete is poured into the frame and steel pipes at once,
A method for installing a main leg member for a deep foundation, comprising fixing the main leg member to the upper end of the steel pipe. 2. The method for installing a main leg member of a deep foundation according to claim 1, wherein the beam member is arranged above a concrete casting surface of the frame portion. The beam material is installed toward the center of the steel tower within the excavation hole,
A tab is attached to the side surface of the steel pipe to be placed on the beam material,
By placing the tab on the beam material, the beam material supports the steel pipe,
The deep foundation according to claim 1 or 2, wherein the position of the steel pipe can be adjusted by moving the steel pipe along the beam with the tab riding on the beam. How to install the main leg of the foundation. 4. The method for installing a main leg member of a deep foundation according to claim 3 , wherein the tab is removable from the steel pipe. 5. The method for installing main leg members of a deep foundation according to claim 1, wherein a reinforcing bar for fixing is attached to the lower end of the steel pipe. After pouring concrete into the body part and the steel pipe,
providing screw holes in multiple directions of the steel pipe at a position above the concrete pouring surface within the steel pipe;
Attach bolts to each of the screw holes,
The method for installing a main leg member for a deep foundation according to any one of claims 1 to 5, wherein the main leg member is fixed after adjusting the position of the main leg member with the bolt.

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