JPS6263721A - Construction work for custom-made pile - Google Patents

Abstract

PURPOSE:To obtain great bearing capacities by a method in which a custom- made pile having a cylindrical bag on its tip is set in an excavated pit, and a cement hardener is injected into the bag to expand the bag under the ground. CONSTITUTION:The ground is excavated by a bit 2 by rotation of an excavating rod 1 while jetting water from its tip, and excavated soil is agitated with water by a stirring arm 3 to a slurry form and the pit wall is solidified by a leveling roller 4. After the rod 1 reaches a desired depth, the rod 1 is reversely turned to expand the bit 2 in a vertically repeated manner into an expanded spherical footing portion 7. The rod 1 is then pulled up and recovered, and a custom-made pile 8 having a cylindrical nylon bag 6 on its tip is set into the excavated pit. A cement hardener is then injected into the bag 6 to expand it into an expanded spherical footing 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a construction method for ready-made piles used as foundations for civil engineering and building structures.

(Prior Art) Various construction methods for ready-made piles have been developed, but low-pollution construction methods are required in urban areas. A pre-poling method is a low-pollution construction method for such ready-made piles.

The conventional pre-poling method is equipped with a stirring arm and a leveling roller, and a drilling rod with a bit at the tip excavates a hole while discharging drilling liquid, and the stirring arm stirs the excavated soil with the liquid to form a slurry. At the same time, the hole wall is leveled with a leveling roller, and after reaching a predetermined depth, enlarged excavation is carried out. After injecting cement milk into the enlarged excavation part and creating an enlarged bulbous part, the drilling rod is pulled up and this A prefabricated concrete pile was inserted into the excavation hole, rotated, and anchored to the enlarged bulb.

In this way, in the pre-poling method, the ground is disturbed once and the piles are sunk, so the bearing capacity of the piles is lower than in the driving method, and as a result, enlarged bulbs are created to increase the bearing capacity. ing.

However, when creating expanded bulbs, the ground is still disturbed, and there are naturally limits to mechanically creating expanded bulbs.

(Problems to be Solved by the Invention) The present invention aims to eliminate the above-mentioned drawbacks of the conventional technology. It creates an enlarged bulb without loosening the ground at the tip of the pile, and increases the supporting capacity of the tip. The purpose is to provide a construction method for ready-made piles that can be made in large sizes.

(Means for Solving the Problems) The present invention has solved the above-mentioned object with the following configuration.The present invention is equipped with an agitation arm and a leveling roller, and excavates while discharging drilling fluid with a drilling iron having a bit at the tip. drill a hole,
The stirring arm stirs the excavated soil with the drilling liquid to form a slurry, and the leveling roller smoothes the hole wall, and expands the excavation to a predetermined depth and for a predetermined length, and then pulls up the excavation loft, A ready-made pile with a cylindrical bag at the tip is sunk into the excavation hole by its own weight, press-fitting, rotation, or a combination of these, and then hardened cement is injected into the cough bag to form the cylindrical bag. This is a method of constructing ready-made piles that is characterized by expanding them underground.

A plurality of stirring arms and leveling rollers used in the present invention are attached in the longitudinal direction of the drilling rod.

The stirring arm can be of various shapes, such as a wing-shaped one, a rod-shaped one, or one having a wing piece at the tip.

The leveling roller kneads the excavated soil by compacting the hole wall by rotating the excavation rod, and can be used in the form of a drum installed around the excavation rod, or in the form of an arc-shaped member.

As the drilling fluid, water, mud, or a ground stabilizing fluid such as bentonite mud is used.

Excavation of the enlarged bulbous portion is carried out by repeatedly moving the excavation rod up and down using a drill that causes the bit at the tip to protrude in the circumferential direction due to the resistance of the soil each time the excavation rod is rotated in the opposite direction. The diameter of the enlarged bulb is preferably about 100 to 200 fins larger than the pile diameter, and the height is preferably about 5 to 10 times the pile diameter.

The ready-made pile having a cylindrical bag at the tip used in the present invention is a pile having a cylindrical bag at the tip of an antibody with both ends attached to the antibody. A stake is inserted into the cylindrical bag, and both ends of the cylindrical bag are attached to the stake using a band, adhesive, or a combination of twists. This pile has an injection port through which hardened cement can be injected after the pile has been sunk, and the hardened cement can be injected by connecting an injection pipe. Further, the bag used in the present invention is made of cloth such as nylon, vinylon, polyester, etc., but films, sheets, etc. of these materials, rubber cylinder sheets, and metal foil sheets may also be used.

However, when cloth is used, if too much water is removed from the bag, it is preferable to prevent water from being removed by coating the bag with rubber coating or the like to make it water-impermeable except for both ends of the bag. The outer diameter of the cylindrical bag is such that the injected cement hardening material can be integrated with the pile after hardening, and preferably the outer diameter of the pile +100 to 200
A crane level is good. Further, after the pile is set, cement milk, cement mortar, cement concrete, etc. are used as the hardened cement material injected into the cylindrical bag.

Whether the cylindrical bag has been sufficiently expanded by injecting the hardened cement material is determined based on the pressure of the pump and the amount of injection. The pressure varies depending on the ground, but it is 3 to 5 k
About g/cm2 is desirable.

The construction procedure of the present invention will be explained below with reference to the drawings.

First, a hollow drilling rod having a drilling bit at its tip is rotated, and a drilling hole is drilled while discharging drilling fluid from the tip. (Fig. 1) At this time, the excavated soil is stirred and mixed with the excavated liquid by the stirring arm to form a slurry, and the excavated soil is kneaded onto the wall of the excavated hole using a leveling roller to stabilize the hole wall.

After reaching a predetermined depth to serve as the supporting ground in this manner, the excavation bit 5 is expanded in the direction of the diameter 2b to perform enlarged excavation. During enlarged excavation, the excavation rod is rotated in the opposite direction, and excavation is repeated in the vertical direction. (Fig. 2-3) Next, the excavation rod is returned to normal rotation 7, and pulled back to recover the shaft (Fig. 4). At this time, water is discharged as necessary to make it easier to sink the pile later. After collecting the excavation rond, a ready-made pile with a cylindrical bag at the tip is placed in the excavation hole.4 (Fig. 5) The pile is placed by its own weight, by press-fitting, by rotation, or by a combination of these.

When sinking a pile, an injection pipe for injecting hardened cement is connected to a cylindrical bag previously installed in the hollow part of the pile, in addition to a resistance connection.

After the pile is sunk to a predetermined depth, hardened cement is injected through the injection pipe, and the cylindrical bag is expanded until the injection pressure reaches a predetermined pressure, thereby creating an enlarged bulbous portion. (FIG. 7) Embodiment An embodiment of the present invention will be described with reference to the drawings.

First, as shown in FIG. 1, the drilling rod 1 was rotated while discharging water from the tip, and digging was performed using the bit 2 at the tip. The diameter of bit 2 is the same as the diameter of the pile to be sunk.
I did it with 00 Dragon φ. During excavation, a stirring arm 3 stirs the excavated soil with water to form a slurry of muddy water 5, and a leveling roller 4 hardens and stabilizes the hole wall.

After the drilling rod 1 reaches a predetermined depth, as shown in Figs. 2 and 3, the drilling rod 1 is rotated in the opposite direction, the bit 2 is enlarged to a bit diameter of 700 * mφ, and the The enlarged bulb part 7 was formed by repeating 4 m.

At this time, hentonite solution was used to stabilize the hole walls of the supporting ground.

Next, as shown in FIG. 4, the drilling rod 1 was pulled up while being rotated in the normal direction. At this time, the piles were raised while discharging water to make it easier to sink them.

After the drilling rod 1 was pulled up and recovered, as shown in FIG. 5, a ready-made pile 8 with a nylon cylindrical bag attached to the tip 4 m of the pile with a band was suspended and sunk into the excavation hole. Here, the cylindrical bag body is made of 73
A material that expanded to 0 niφ was used.

The connection of the pile 8 was performed by welding the upper pile and the end metal fittings of the upper pile, as is usually done. The piles were installed using their own weight and press-fitting. In this manner, the pile was sunk, and the tip of the pile 8 was embedded into the enlarged bulb part 7, as shown in FIG. At this time, the injection pipe 10 for injecting hardened cement into the cylindrical bag at the tip of the pile was connected at the same time as the resistance connection.

The injection tube 10 was connected using a conventional collar coupler 13 as shown in FIG. In addition, the injection pipe 10 is a PVC pipe of IA inch size, and it is made to protrude above the pile head after being sunk, and a valve 14 with a check valve is attached to the tip of the pipe as shown in Fig. 9. Installed to prevent backflow of hardened cement.

Next, using a low-pressure mortar pump, a hardened cement product prepared by adding an anti-bleeding agent to cement milk at a water-to-cement ratio of 67% and an anti-breathing agent at a ratio of 1% to the cement was injected into the bag through the injection pipe 10. Whether the nylon cylindrical bag was sufficiently expanded by the cement milk was determined based on the pump pressure and the amount of cement hardened material injected. In this case, the injection pressure of the pump was 3 kg/aA, and the injection volume was 90 kg/aA.
0I! Therefore, it was estimated that the nylon cylindrical bag expanded sufficiently, and the bulb expanded to an average diameter of 730 mm.

(Effects of the Invention) According to the construction method of the present invention, hardened cement is injected under pressure into the cylindrical bag attached to the tip of the pile and expanded to a predetermined diameter, making it possible to create a completely expanded bulb. Since the surrounding ground loosened during excavation can be restored by the expansion force of the bag, a large supporting capacity can be obtained. Therefore, as a result, the number of piles can be reduced and the diameter of the piles can be reduced in terms of design, making it possible to design economically.

[Brief explanation of the drawing]

Figures 1 to 7 show the construction procedure of the present invention.
The figure is an excavation process diagram, Figures 2 and 3 are enlarged excavation process diagrams, Figure 4 is an excavation entrance and recovery process diagram, Figure 5 is a pile installation process diagram, and Figure 6 is a pile The submergence state diagram, Figure 7, is a diagram of the process of creating the expanded foot protection section. 8 and 9 are detailed views of the injection tube. 1... Drilling rod, 2... Bit, 3... Stirring arm, 4... Leveling roller, 5... Mud water, 6...
Tubular bag body, 7... Expanded root hardening part, 8... Ready-made pile, 9.
... Rotating cap, 10... Injection tube, 11... Resisting end plate, 12... Bag body fixing band, 13... Injection tube connection collar, 14... Valve with check valve. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] A drilling rod equipped with an agitation arm and a leveling roller is used to excavate a drilling hole while discharging drilling fluid, and the agitation arm stirs the excavated soil with the drilling fluid to form a slurry. The hole wall is leveled with a roller, and enlarged excavation is performed for a predetermined length at a predetermined depth.Then, the drilling rod is pulled up and a ready-made pile having a cylindrical bag at the tip is deposited in the excavation hole, and then, A method for constructing ready-made piles, characterized by injecting hardened cement into the bag and inflating the cylindrical bag underground.