JPH10140586A - Precast foundation for deep foundation - Google Patents

Abstract

(57) [Summary] [Problem] A precast foundation for deep foundation foundation that can achieve a uniform concrete quality factory and reduce the number of workers in boreholes and simplify work, regardless of the weather, in concrete casting. Provide body. SOLUTION: Concrete blocks created in a predetermined shape are stacked and assembled to construct a predetermined foundation structure. The concrete block can penetrate the rebar that integrates the blocks when the foundation is constructed,
The concrete block was made cylindrical by assembling the concrete block, and a gap was provided inside the base body. In addition, the concrete block flows fluid such as cement mortar vertically and horizontally.
By providing a through hole that can be discharged, solidification and integration of the foundation by injecting cement mortar and close contact between the foundation and the excavated ground can be achieved. Further, the concrete block was provided with a projection or a groove that fits unevenly with the adjacent concrete block.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for forming a foundation of a steel tower for erection of a transmission line or the like, and more particularly to a deep foundation. The deep foundation includes a deep foundation having a void inside the foundation.

[0002]

[Prior art]

1. Method of forming a deep foundation for transmission line; excavating a deep foundation hole to secure the foundation diameter and depth against the compressive and pulling forces applied to the steel tower foundation, and rebars in the foundation hole against the lifting force applied to the concrete of the foundation After placing the concrete to the location of the tower and installing the tower material and installing the tower material, further concrete placement, backfilling of part of the excavated soil, and transporting most of the excavated soil.

[0003] 2. A method of forming a deep foundation with a void inside the foundation body; (1) excavating a deep foundation hole under the same design conditions as the previous method, (2) placing rebar in the deep foundation hole under the same design conditions as the previous method, ( 3) Pour concrete up to the bottom of the gap, (4) Install a frame to secure the gap, (5) Pour concrete between the deep foundation hole and the frame, (6) After concrete hardens , Remove the frame, and (7) fill back a part of the excavated soil in the void surrounded by the concrete, and (8) pour concrete up to the installation position of the tower material above the void filled with the excavated soil. A cover is installed in the void, (9) steel tower material is installed, concrete is further poured, (10) part of the excavated soil is backfilled, and (11) the rest of the excavated soil is carried out.

[0004] In both the first and second construction methods, the foundation is cast into fresh concrete and finished in a predetermined shape. As a result, the excavated ground and the foundation are brought into close contact with each other, and are designed to withstand the tower lifting load.

[0005]

Among the above-mentioned prior arts, the method for forming a power transmission tower foundation has the following problems. Due to outdoor work, concrete cannot be cast in rainy weather. For transporting concrete to a steel tower placement point,
Helicopters and cableways are required, and the amount of concrete poured per day is determined by this transportation method. It takes time to transport from the ready-mixed concrete plant to the casting site, and the quality of concrete deteriorates. The concrete strength is designed in anticipation of the deterioration of concrete quality. While concrete is being cast into a deep foundation hole, workers are required inside the hole. Preparing for concrete placement, cleaning after placing, clearing, etc. are troublesome.

Further, there is the following problem in the arrangement of reinforcing bars.
The depth of the deep foundation hole is about 20 m above the ground, and it is necessary to arrange a worker on the ground and in the hole when inserting a reinforcing bar into the hole. It takes time and effort to assemble the rebar placed in the hole into a cage.

Further, the method for forming a deep foundation having a void inside the foundation has the following problem. (1) It takes time to install and remove the frame that secures the gap. (2) The cost of the frame for securing the void is high. (3) The frame that secures the gap moves when the surrounding concrete is poured. (4) The number of concrete castings increases.

Therefore, the main problems (objects) of the present invention are:
It is an object of the present invention to provide a precast foundation for a deep foundation, in which a concrete casting plant can be made uniform and the number of workers in a hole can be reduced and the operation can be simplified irrespective of the weather in concrete casting.

Another object (object) of the present invention is to provide a precast foundation for a deep foundation, which can reduce the number of staff and simplify the work in arranging reinforcing bars. Another object of the present invention is to provide a precast foundation for a deep foundation, in which a frame can be omitted and concrete around the frame can be omitted in forming a void foundation.

[0010]

A precast foundation for a deep foundation provided by the present invention is constructed by stacking concrete blocks formed in a predetermined shape by stacking them.
It is constructed by building a predetermined basic structure.

[0011] As an embodiment, the concrete block can be made to penetrate a reinforcing bar that integrates the blocks when the foundation is constructed, and the concrete block is made cylindrical by assembling the concrete block so as to have a void inside the foundation. To provide a structure.

Further, the concrete block has through holes through which a fluid such as cement mortar can flow in and out in a vertical and horizontal direction, and solidifies and integrates the foundation by injecting the cement mortar and adheres the foundation to the excavated ground. Provide a structure that can be achieved. Further, the concrete block can be provided with a structure having a projection or a groove that fits unevenly into the adjacent concrete block.

[0013]

1 and 2 show an embodiment of a precast foundation for a deep foundation according to the present invention. FIG. 1 shows a precast foundation for a deep foundation having a gap for a transmission line. FIG. 2 is a perspective view schematically showing the assembling state of the concrete block.

The deep foundation of this embodiment is constructed by stacking circular arc-shaped concrete blocks 1 in a cylindrical shape, assembling them, piercing upper and lower concrete blocks with reinforcing bars 3 in a skewered state, and tensioning both ends of the concrete blocks. To form the base body 2 having the voids 4. The size of the gap 4 can be arbitrarily set by changing the number of assembling the concrete blocks 1.

The concrete block 1 is formed into an arc shape obtained by dividing a circle into quarters, and has three longitudinal through holes 5 in the circumferential direction.
Having. Then, four concrete blocks are combined in the circumferential direction into a cylinder, and 45 ° in the circumferential direction upward.
By shifting and stacking, the seam in the circumferential direction is not connected vertically, and in any of the upper and lower adjacent concrete blocks, the reinforcing bar 3 penetrates through the upper right side hole and the lower left side hole communicating vertically. Finally, the concrete blocks are integrated by tightening the upper and lower ends with nuts or the like.

The above-mentioned concrete blocks can be stacked and assembled by lowering them in the excavation hole and stacking them on the reinforcing bar mounting base 8 with the reinforcing bars 3 serving as guides. In this case, as shown in FIG. 4, the concrete block 1 is provided with projections 9 and grooves 10 which can be fitted into the upper and lower end faces so that the concrete block 1 can be lowered to a target position when the concrete block 1 is lowered. It becomes easy to stack.

As shown in FIG. 3, the concrete block 1 has a through hole 6 and a groove 7 at an end into which cement mortar can be injected.
By injecting mortar at the time of stacking and assembling, the integration of the concrete block group can be enhanced.

The tension of the reinforcing bar 3 is maintained in a tensioned state by a commercially available tensioning jack and a fixing tool. In this state, cement mortar flows into the gap between the concrete block 1 and the reinforcing bar 3,
After the concrete block and the rebar are integrated by mortar consolidation, the tension fixture is removed. It is recommended that the tension be applied up to the design pulling force applied to the tower foundation. The diameter and the number of the reinforcing bars 3 are adjusted according to the tension, but the reinforcing bars 3 can be replaced with PC steel wires mainly used in general construction.

The holes of the concrete block shall penetrate the surface in contact with the ground, or give a space to the ground side during stacking by deformation of the block shape, and fill the gap between the foundation and the excavated ground by injection of cement mortar. Adhesion with the ground can be achieved.

According to the precast foundation for a deep foundation having the above structure, the following effects can be obtained. 1. Concrete placement; can transport concrete regardless of the weather, improve and equalize concrete quality (concrete blocks are produced in advance at the factory), reduce the number of workers in the hole, omit preparation, cleaning and clearing work (on site) The number of ready-mixed concrete is reduced.) 2. Rebar arrangement; reduction of staffing and simplification of work. 3. Formation of void foundation; elimination of frame, elimination of concrete around frame.

[0021]

According to the present invention as described above, in concrete placing, the quality of concrete can be made uniform with the factory regardless of the weather, the number of workers in the hole can be reduced, and the work can be simplified. Thus, the intended problem (objective) of providing a precast foundation body for a deep foundation can be achieved.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a precast foundation for a deep foundation having a void portion in a see-through state according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a perspective view of an assembling state of a precast foundation for a deep foundation constructed of concrete blocks according to the embodiment of the present invention.

FIG. 3 is a perspective view showing the state of holes and grooves in a concrete block according to the embodiment of the present invention.

FIG. 4 is a perspective view showing a state of irregularities of a concrete block according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concrete block 2 Foundation 3 Reinforcing bar 4 Void portion 5 Hole 6 Mortar through hole 7 Groove 8 Reinforcing bar mounting base 9 Protrusion 10 Groove

Claims (5)

[Claims] 1. A precast foundation for a deep foundation, wherein concrete blocks formed in a predetermined shape are piled up and assembled to construct a predetermined foundation structure. 2. The concrete block is capable of penetrating a reinforcing bar that integrates the blocks when the foundation is constructed.
A precast foundation for a deep foundation as claimed in claim 1. 3. The precast foundation for a deep foundation foundation according to claim 1, wherein the concrete block is formed into a cylindrical shape by assembling the concrete block so that a void portion is provided inside the foundation. 4. The precast foundation for a deep foundation according to claim 1, wherein the concrete block has a through hole through which a fluid such as cement mortar can flow in and out in a vertical and horizontal direction. 5. The precast foundation for a deep foundation according to claim 1, wherein the concrete block has a projection or a groove which fits unevenly with an adjacent concrete block.