JPS62248711A - Formation of pile using cloth cylinder coated with rubbery paint - Google Patents

Abstract

PURPOSE:To form a cylindrical hardened material by a method in which a specific cylinder is penetrated to a given depth into the ground, and a hydraulic slurry is charged under pressure into the upper end of the cylinder and excessive water of the slurry is removed while expanding the cylinder. CONSTITUTION:The lower end of a flexible cylinder 1 made of cloth whose surface and back sides are at least partly coated with a rubbery paint is closed and the upper end is an injection hose 5 connected to a pump. Cement mortar is injected into the cylinder l by the pump to expand the cylinder 1, the pump is stopped at a given pressure, and the excessive water of the mortar is removed from the cloth to form a hardened columnar body 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for constructing piles used when constructing foundations for civil engineering and architectural structures.

(Conventional technology and problems) Conventionally, when trying to build a structure on soft ground,
There were two ways to obtain a safe foundation. That is, the first method is ground improvement, which involves mixing hardening materials such as cement into soft ground and hardening it.
This included ways to increase the bearing capacity of the ground.

The second method is to drive piles, and the pile materials used are cast-in-place concrete piles and ready-made piles (prestressed concrete piles, reinforced concrete piles, steel pipe piles, etc.), and each method uses various existing construction methods. It is being constructed.

In the conventional foundation construction method, the method of mixing hardening materials such as cement into soft ground is based on ground improvement.
Since the soft ground itself, which is a natural material, is used as a material, the constituent elements, water content, etc. of K vary widely, and a high degree of technical judgment was required to select a hardenable material. Furthermore, it has been extremely difficult to uniformly improve soft ground over a wide area three-dimensionally.

Recently, a construction method has also been developed to improve soft ground by pumping coal ash slurry into a cylindrical cloth bag made of synthetic fibers (Kensetsu Gijutsu Shimbun, published on January 16, 1986). This requires a long injection pipe that is at least as long as the cylinder length, and the slurry must be gradually injected from the bottom while maintaining a predetermined pressure while the injection and U are pulled up, making the process complicated. Since the formed hardened body is mainly composed of coal ash slurry, it is difficult to find a product of sufficiently high quality in terms of strength characteristics.

Furthermore, a method of pouring concrete without making direct contact with the surrounding ground by using rubber bags, etc., has been developed.
(Japanese Patent Application Laid-Open No. 58-156620), this method also requires a steel injection pipe with a length equal to or longer than the pile length, and when pouring concrete, the injection pipe must be pulled up while pouring, making the process complicated. It lacked practicality.

In any case, cast-in-place concrete piles require a curing period of approximately one month after concrete placement, and are inferior in economic efficiency in terms of construction period.

Next, among the methods of driving a single pile, cast-in-place concrete piles use mechanical force such as a packet or drill bit to create a hole in the ground, and then use a hole wall stabilizing liquid such as bentonite to prevent the wall from collapsing while reinforcing the concrete pile. However, there are many difficulties in dealing with the slime that forms at the bottom of the hole and managing muddy water, and the performance of the piles is limited because the concrete is placed in direct contact with the ground. In the case of prefabricated piles where there is a problem with the quality of the concrete that is the basis of construction, the pile body and construction equipment are generally large, making construction impossible in narrow urban areas due to space restrictions. There were many cases where this happened. In addition, due to pollution problems such as noise and vibration, it is no longer possible to adopt the percussion method, which has a large bearing capacity, so we have no choice but to use non-polluting construction methods, which have a lower bearing capacity than the percussion method, which reduces economic efficiency. There was a problem.

(Means for Solving the Problems) The present invention has been made to eliminate the drawbacks of the prior art, and its purpose is to provide PIR convenience and reliably higher quality than using a fabric tube. The purpose is to build a pile.

The present invention involves inserting a flexible cylindrical body with a closed end made of a fabric coated with rubber paint on at least one side of the front and back into the ground to a predetermined depth, and then applying hydraulic slurry from the upper open end of the cylindrical body. A fabric cylindrical body coated with a rubber-based paint is used, which is characterized by expanding and expanding the cylindrical body by press-fitting the cylindrical body, and removing excess water from the hydraulic slurry through the fabric to create a cylindrical cured body. The fabric coated with the rubber paint used in the present invention, which is a method for building piles, is made of natural fibers (cotton, hemp, etc.), synthetic fibers (nylon, polyester, polypropylene, polyethylene, etc.) and other fibers. Apply a TM-based paint (for example, polyurethane, polysulfide-based synthetic amorphous rubber) to a thickness of 2 to 3 g1IR (approximately 1.2 g/cm") on at least one surface layer of the fabric using a brush, spatula, etc. It is a fabric obtained by

When the hydraulic slurry is injected into the fabric tube according to the present invention, the rubber coating film on the fabric surface acts as an elastic sam-like sealing material in the initial stage of injection, sealing the fabric's mesh. As a result, the mesh of the fabric becomes clogged, and the fabric constituting the cylindrical body functions as a kind of water-permeable membrane material. Therefore, the hydraulic slurry press-fitted into the inside of the cylindrical body is suppressed from being quickly dehydrated, so that the inside of the cylindrical body has a relatively uniform pressure distribution state, and the cylindrical body has an almost uniform pressure distribution up to the tip. It is expanded and expanded. Then, in the final process of injection, high pressure is applied inside the cylinder, causing the fabric to stretch and open its openings, resulting in rapid dewatering from the hydraulic slurry, resulting in a high-quality cylindrical cured body. can be created.

In other words, the fabric cylinder coated with the rubber paint according to the present invention can remove water from the hydraulic slurry at a predetermined pressure (
0.5 to 5 K4f/cm") is suppressed by the action of the rubber coating film, and furthermore, the high internal pressure in the final process of high pressure injection of hydraulic slurry (approximately 5 to 15 hours)
Sufficient tensile strength (50-
1000Kff/cm).

The outer diameter of the fabric cylindrical body used in the present invention is about 10 to 40 mm, and the method for inserting the fabric cylindrical body into the ground is to prepare an excavation hole with a predetermined diameter or less in advance, and insert the fabric cylindrical body into the hole. However, if the ground is soft, it is also possible to grasp the tip of the cylindrical body with the end of the shaft and push it directly into the ground. When an excavation hole is prepared in advance and the fabric cylindrical body is inserted, the diameter of the excavation hole is sufficient as long as the fabric cylindrical body can easily fit therein, and usually, it is sufficient that the diameter of the excavation hole is about half the outer diameter of the cylindrical body.

In addition, the hydraulic slurry injected into the fabric cylinder from the ground surface may be made of cement, gypsum, lime, pozzolan, slag, or other materials, either singly or in combination, as long as it can be pumped. Although it is possible to
From the viewpoint of economy, fluidity, strength characteristics, etc., cement-based mortar and concrete are preferable.

The method of injecting the hydraulic slurry into the inside of the fabric tube is as follows: pump press-fit from the upper open end of the tube with a large injection pressure of 10 Kq.
f/(7)2), but this method is simple, quick, and economical for mosquitoes.

(Effect of the invention) The invention has the following advantageous features.

■Since a fabric tube is used that can expand with the injection pressure of hydraulic slurry, the drilling hole for inserting the fabric tube only needs to be less than half the outer diameter of the tube, making it easy to use small construction machines. It is possible and economical to construct.

■A fabric cylindrical body coated with a rubber-based paint is used, and when the cylindrical body expands, the clogging effect of the PUM-based coating suppresses the dehydration of the hydraulic slurry, and the inside of the cylindrical body is drained first. By transmitting pressure to the ridges, the cylindrical body expands and expands almost uniformly over its entire length without clogging, and eventually the clogging effect is almost eliminated due to the stretching of the fabric due to the high internal pressure. Significant water removal from the aqueous slurry can be achieved through the fabric.

(2) Since the inside of the fabric cylinder is filled with hydraulic slurry, the hydraulic slurry does not come into direct contact with the ground, and a high-quality cured body can be obtained.

(2) Since the hydraulic slurry is pumped into the fabric tube from the open end of the upper part of the fabric tube at the ground surface, the construction is simple, quick, and economical.

■During construction, there is no noise or vibration, and there is no need for treatment of mud removal, drainage, etc., and the construction can be carried out without pollution.

As described above, an inexpensive and highly reliable cylindrical cured body according to the present invention can be obtained reliably and easily without any pollution.

(Example) Hereinafter, the present invention will be explained in detail with reference to Examples.

Examples and Comparative Examples As shown in FIG.
A cylindrical body made of fabric coated with 300+w+ ZAM-based paint was inserted using a 5000m long steel rod (
(See figure 1). Next, an injection hose connected to a mortar injection pump is tied to the upper open end of the cylindrical body, and the pump causes the inside of the cylindrical body Ifx, 5-Js-knee=-&sI
4/(-1-“11011i!714SFIZJ1-+
``The p1 paint is a polysulfide sealing material manufactured by Yokohama BIM Co., Ltd. (matite) in a solvent (toluene),
They were mixed at a weight ratio of 1:1 and used.

A total of five pressure sensors were installed on the steel rod used to insert one cylindrical body in order to measure the state of pressure distribution inside the fabric cylindrical body during injection. The pressure sensor is 500 mm below the ground surface.
．． They were placed near the central axis of the cylindrical body at positions of 1500, 2500, 3500° and 4500 sa*. In addition, a pressure sensor was placed in the middle of the injection hose to measure the pressure at the source of injection by the mortar pump.

After injection started, the injection source pressure did not rise at all until the inside of the cylinder was filled with mortar, but as the cylinder expanded and expanded and the diameter became larger, the injection source pressure of the pump increased. The pressure starts to rise and this pressure reaches 10'Kgf
/ cm”, the pump was stopped and the injection was completed (
(See Figure 1(C)).

The pressure distribution state inside the cylindrical body when the pump is stopped is
Indicated by the solid line in the figure.

For comparison, the state of pressure distribution was measured in the same manner using a fabric tube which had not been subjected to the BIM coating described above. The results are shown by the broken line in FIG.

As a result of a later excavation survey, it was found that the one using a cloth cylinder coated with rubber paint (example) was formed into a completely cylindrical hardened body, and its outer diameter was approximately 165W over the entire length. It was before and after.

On the other hand, the upper end (ground surface) of the fabric cylinder that is not coated with rubber paint (comparative example) is approximately 165 m long.
However, at deeper depths, the outer diameter gradually decreased, especially at depths deeper than about 2,000 sm below the surface, where the outer diameter was about 80 mm, which is about the same as the diameter of the borehole.

Figure 3 shows an external view of these two excavated hardened bodies.

The mortar injected in this example has a cement/sand weight ratio of 0.5 and a water/cement weight ratio of 0.60.
This is mortar.

Furthermore, the fabric used in this example that was not coated with the rubber paint was a nylon woven fabric with a tensile strength of approximately 200 Kff/cHI, and the fabric coated with the rubber paint was a woven nylon fabric with a tensile strength of approximately 200 Kff/cHI. It is a fabric coated all around.

[Brief explanation of drawings]

Fig. 1 shows each step of the method of the present invention, Fig. 1 (A) is a partially cutaway sectional view of a fabric tube coated with rubber paint inserted into the ground, Fig. 1 (δ) The figure is a partially cutaway cross-sectional view showing hydraulic slurry being injected from the open end of the surface of the fabric tube using an injection hose, No. 1 (C)
The figure is a partially cutaway cross-sectional view of a cylindrical hardened body that has expanded, expanded, dehydrated, and solidified in the ground. FIG. 2 is a graph showing the pressure distribution state when the I'/' is stopped in the example and the comparative example. FIG. 3 is a schematic diagram of the appearance of the cured product in the example and the comparative example, FIG. 3A1 is the appearance of the cured product in the example, and FIG. 3(B) is the appearance of the cured product in the comparative example. 1 is a fabric AI cylindrical body coated with a rubber paint, 2 is an excavation hole, 3 is an upper open end of the fabric cylindrical body, 4 is a hydraulic slurry, 5 is an injection hose, and 6 is a cured body of the hydraulic slurry. Patent applicant: Asahi Kasei Industries, Ltd. Figure 1

Claims (1)

[Claims] A flexible cylindrical body with a closed end made of a fabric coated with rubber paint on at least one of its front and back surfaces is inserted into the ground to a predetermined depth, and then hydraulic slurry is applied from the open upper end of the cylindrical body. A fabric cylindrical body coated with a rubber-based paint is characterized in that the cylindrical body is expanded and expanded by press-fitting, and excess water of hydraulic slurry is removed through the fabric to create a cylindrical cured body. Method of constructing piles used