JPH064969B2 - Method of constructing piles using fibers - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of constructing a pile used when constructing a foundation of a civil engineering building structure, and more particularly to a method of constructing a pile using fiber using a fiber material. Is.

(Prior Art) Conventionally, when attempting to build a structure on soft ground,
There were two ways to get a safe foundation. That is, the first is a method of ground improvement, which is a method of mixing a hardened material such as cement into soft ground, and a permeable material (for example, sand, gravel, etc.) is cast in a column shape to consolidate the soft ground. There were ways to promote and increase the bearing capacity of the ground.

The second is a method of driving piles. As the pile material, cast-in-place concrete piles and ready-made piles (prestressed concrete piles, reinforced concrete piles, steel pipe piles, etc.) are used. Has been constructed. There are two ways to use the pile: one is to insert the pile up to the strong support ground (hereinafter referred to as a support pile), and the other is to stop it in the middle of the soft ground without being embedded (hereinafter referred to as a friction pile). There were two cases.

(Problems to be solved by the invention) In the conventional foundation construction method, among the methods for ground improvement, in the method of mixing a hardened body such as cement into soft ground, since the soft ground itself of a natural material is used as a material,
The constituent elements, the water content ratio, etc. are varied, and a high degree of technical judgment was required to select the hardened material. Furthermore, it is extremely difficult to improve the soft ground uniformly over a wide area in three dimensions.

Further, in a method of driving a water-permeable material such as sand or gravel into a columnar shape to promote consolidation of soft ground, the water-permeable material that has been placed due to deformation of the ground may be cut in the middle, or clogging may cause pumping action. It was often impossible to exert it. For the purpose of improving this, a method has been developed in which a bag of a cloth formwork is filled with a water-permeable material and placed in soft ground, but since the bag is placed in the ground, the target ground is extremely soft. It is not limited to one, and the construction machine is also large and it is not something that can be easily constructed. Next, of the methods of placing piles, in-place concrete piles are provided with holes in the ground due to mechanical forces such as buckets and drill bits, and reinforcing rods are used to prevent collapse of the hole walls by a hole wall stabilizing liquid such as bentonite liquid. It is constructed by pouring the concrete and pouring concrete, but there are many difficulties in treating the slime that accumulates at the bottom of the hole and managing mud water.Because the concrete is placed directly in contact with the ground, There was a problem with the quality of concrete, which is the basis of performance.

In the case of ready-made piles, the impact construction method, which has a large bearing capacity, cannot be adopted because of pollution problems such as noise and vibration.Therefore, the pollution-free construction method, which has a lower bearing capacity compared to the impact method, must be used, which is economical. There was a problem that it decreased.

(Purpose of the Invention) One of the inventors of the present invention has previously proposed in Japanese Patent Laid-Open No. 55-89526 a method for driving a precast pile that can reduce noise and vibration, but the present invention is concerned with the stress. This is done in order to eliminate the drawbacks of the above-mentioned prior art. Its purpose is to provide a method of constructing a drain pile, a support pile or a friction pile for soil improvement without pollution by using a fiber material.

(Structure of the invention) When a hollow pile is driven into the ground, if the sand and sand that penetrates into the hollow portion has a characteristic that the volume expands upon shear failure, the sand and sand will remain at a certain position, and As described above, the phenomenon that the hollow portion is not penetrated occurs. The present invention is an application of this phenomenon, in which a granular body made of sand, slag, or gravel having an unsaturated water content is provided inside the hollow pile which is tightly bonded to the end of the tubular body made of cloth. When the granules are filled to a height of 3 times or more and hit with a rammer, the tips of the hollow piles are closed by the granules, and by further striking, the hollow piles are driven into the ground and become hollow piles. The connected cloth tubular bodies are also dragged into the ground to form a space. Using this space, piles will be constructed according to the purpose.

The present invention will be described below with reference to the drawings showing an embodiment thereof.

In FIG. 1, a hollow pile 2 of a steel pipe having an open tip is connected to one open end of a cloth tubular body 1 by connecting the hollow portions to each other,
The hollow pile 2 is filled with a granular material 3 such as sand, slag, or gravel. The hollow pile 2 is driven into the ground 4. At the time of driving, the rammer 5 is inserted by inserting the connected cylindrical body 1.
With this, the granular body 3 in the hollow pile 2 is struck, the tip of the hollow pile 2 is closed with the compacted granular body, and the hollow pile 2 is struck at a predetermined depth position in the ground 4 by further striking. Along with this driving, the tubular body 1 connected to the hollow pile 2 is drawn into the ground 4 to form a space 6.

In this way, the hollow pile 2 and the cloth tubular body 2 up to a predetermined depth
After driving, the selected material is filled into the space 6 formed by the tubular body 2 to form a pile.

That is, as shown in FIG. 2, reinforcing material 7 is reinforced in the space 6 to reinforce, sand or fine gravel 8 is filled as shown in FIG. 3, or porous mortar or concrete is filled as shown in FIG. The water permeable material 9 is filled to form a drain pile. By filling the porous water-permeable material 9, it is possible to obtain a pile having an intermediate property between the support pile, the friction pile and the drain pile.

Next, as shown in FIG. 5, mortar or concrete 10 can be filled into the tubular cloth body 1 to form a support pile or a friction pile. Whether to use the support pile or the friction pile may be determined in advance in consideration of the properties of the ground, the load of the superstructure, the structural type, and the like. When filling mortar or concrete, it may be unreinforced, or in consideration of bending stress generated in the pile due to horizontal force during an earthquake, etc., insert the full length or part of multiple reinforcing bars 11 in the length direction. It may be reinforced.

As the material of the cloth tubular body 1 used in the present invention, natural fibers (cotton, hemp, etc.), synthetic fibers (nylon, polyester, polypropylene, polyethylene, etc.) and other fibers can be used. Further, in order to counter the tensile stress generated at the time of hitting, for example, steel wire, polyacetal fiber, aramid fiber, carbon fiber, alumina fiber, etc., which are resistant to tensile stress in the longitudinal direction of the cloth tubular body 1, are arranged as the reinforcing material 7. You may.

Further, the granular body 3 packed in the hollow pile must have a property of expanding in volume upon shear failure. Sand, slag, gravel or the like having an unsaturated water content is suitable.
Grain soil or unhardened concrete, mortar, etc. are unsuitable and do not act to close the open tip of the hollow pile 2. When the hollow pile 2 is driven in, a part of the granular material 3 is extruded into the ground 4 until the tip is closed. It may be necessary to replenish on the way. The height at which the granules 3 are packed varies depending on the N value of the ground, but in the case of hollow piles such as steel pipes, it is necessary to make it 2-3 times or more the inner diameter. When the groundwater is high, the water hardly penetrates and the blocking effect is hard to occur. Therefore, it is preferable to temporarily block the open end of the hollow pile with a thin iron plate or the like and pack the granular body 3. There is no problem even if the thin iron plate is damaged after the pile tip is closed by the granular body 3.

(Advantages of the Invention) The present invention has the above-mentioned configuration and has the following advantages and characteristics as compared with the conventional technology.

Since the granular material is hit, it acts as a buffer, and it can be installed without pollution without generating noise or vibration.

Since the hollow pile such as a steel pipe penetrates into the ground before the cloth tubular body, the cloth tubular body can be easily installed even in the hard ground and the pile diameter can be surely secured.

Since the tubular body made of cloth is used, even if the ground is deformed, the sand and fine gravel filled inside are not cut.

The cloth tubular body can function as a drain material for a long period of time without clogging of sand or the like filled inside.

Since the mortar or concrete is filled inside the cloth tubular body, the hole wall does not collapse even without using muddy water, and high quality mortar or concrete can be obtained because it does not come into direct contact with the ground.

As described above, according to this method, an inexpensive and highly reliable basic structure can be obtained without pollution and easily.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a construction state of construction of a pile of the present invention, FIG. 2 is a side view showing a partial cross-sectional view when a reinforcing material is arranged in a cloth tubular body, 3, 4, 5 FIG. 6 is a vertical sectional view of a pile in which sand, fine gravel, porous mortar and concrete are filled in a tubular body made of cloth, and FIG. 6 is a transverse sectional view of FIG. DESCRIPTION OF SYMBOLS 1 ... Cylindrical body made of cloth, 2 ... Hollow pile, 3 ... Granular body, 4 ... Ground 5 ... Rammer, 6 ... Space, 7 ... Reinforcing material, 8 ... Sand, fine gravel, 9 ... Water permeable material, 10 ... Concrete, 11 ... Rebar.

Claims (1)

[Claims] 1. A hollow pile is connected to one open end of a tubular cloth body, and the hollow pile is filled with a granular body that expands in volume upon shear failure, and the granular body is hit. The tip of the hollow pile is closed with a granular body and the hollow pile is driven into the ground, and at the same time, the cloth tubular body connected to the hollow pile is drawn into the ground, after which the water-permeable material or hydraulic property in the cloth tubular body. A method for constructing a pile using fibers, which is characterized by filling a material.