JPS6133931B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing an underground pile in which a cylinder for an underground pile and an earth auger positioned inside the cylinder are inserted into the ground while rotating together.

In the above construction method, noise and vibration can be reduced by inserting the pile cylinder while rotating and by excavating the vicinity of the lower end of the pile cylinder using an earth auger in advance of the pile cylinder. It has the advantage of being able to work while suppressing the occurrence of. However, conventionally, an earth auger with an outer diameter approximately equal to the inner diameter of the pile cylinder has been used, and in this case, almost all of the excavated earth and sand is transported to the outside of the pile cylinder. As a result, the amount of soil removed increases, and the bottom surface of the pile cylinder is narrow enough to correspond to the wall thickness of the cylinder, which has the disadvantage of low support strength against loads from above. Furthermore, when inserting the pile cylinder to a predetermined depth after reaching the support layer, a method is adopted in which the pile cylinder is rotated and an earth auger is used. Since the earth and sand around and below the cylindrical body is removed by excavation, there is a drawback that the supporting force of the support layer against loads applied in the lateral direction and above the cylindrical body is reduced.

The present invention reduces noise and vibration while
Piles can be inserted with the amount of earth removed being kept to a minimum and the insertion direction is reliably oriented in the desired direction, and the pile can be supported after construction against loads from both upward and lateral directions. The purpose is to provide a construction method that can be robustly implemented.

Next, embodiments of the present invention will be described based on the drawings.

As shown in Figures 1 and 2, it has an outer diameter that is approximately 1/2 of the outer diameter of the underground pile cylinder 1, and a length that is approximately 5 times the outer diameter of itself. The provided cylinder 2 is concentric or almost concentric with the pile cylinder 1, and an annular space S is formed between the pile cylinder 1 and the pile cylinder 1. a ring-shaped member 3 for connecting the cylinder 2 to the pile cylinder 1' and closing the annular space S at the front end of the pile cylinder 1; Ribs 4 for increasing the mounting strength of the member 3 are provided in series on the tip side of the pile cylinder 1. Furthermore, the earth auger 5 is adjusted so that the outer diameter of the screw is adjusted so that soil remains around the inner circumference of the pile cylinder 1.
and about 20 mm smaller than the inner diameter of the cylindrical body 2.
It is formed to be relatively small, and a nozzle 6 is attached to the tip of the screw cylinder shaft of the earth auger 5.

Then, as shown in FIG. 3, the earth auger 5 is positioned inside the pile cylinder 1 with the tip side penetrating the cylinder 2, and the tip of the earth auger 5 is inserted from the cylinder 2 into the pile cylinder 1. It protrudes by a length approximately equal to the outer diameter of the cylindrical body 1, and applies forward driving force of about 10 rotations per minute to the head of the earth auger 5, and at the same time, the head of the cylindrical body 1 is opposite to the earth auger 5. The cylinder body 1 and the earth auger 5 are placed underground while applying a driving force and a pressing force of about 5 times per minute in the same direction, and while spouting compressed air of about 5 kg/cm ² from the nozzle 6. insert.

In other words, the cylinder 1 is rotated, the soil near the tip of the cylinder 1 is excavated by the earth auger 5, and the excavated soil is clogged inside the cylinder 1 by the cooperation of the earth auger 5 and compressed air. By discharging soil a from the cylinder as a guide, the generation of noise and vibration can be suppressed and the pile cylinder 1 can be discharged as a guide.
By using the earth auger 5, which is thinner than the inner diameter of the
Furthermore, the cylindrical body is inserted while taking into account that the earth auger 5 is rested by the cylindrical body 2 and that the cylindrical body 1 is inserted in the desired direction. In this case, depending on the soil quality such as the N value, compressed air may not be used.

Then, as shown in FIG. 4, when the tip of the pile cylinder 1 reaches near the upper end of the support layer A, as shown in FIG. 5, it is pulled up while rotating the earth auger 5 in the opposite direction.

After the earth auger is lifted up, as shown in Fig. 6, a hydraulic hammer is attached to the head of the pile cylinder 1.
Pile driver 7 such as Diesel pile hammer and Monoken
The pile cylinder 1 is driven into the supporting layer A until its tip reaches a predetermined depth in the support layer A, and the compressive action accompanying the driving hardens the ground around and below the pile cylinder 1, creating a hardened ground. With the large pile bottom area formed by the ring-shaped member 3, an underground pile that can be firmly supported against loads from above and from the sides is completed.

In summary, in the method for constructing an underground pile according to the present invention, the pile cylinder 1 is placed on the tip side of the underground pile cylinder 1.
A cylinder 2 having a concentric or almost concentric shape is inserted and connected in a state where an annular space S is formed between this cylinder 2 and the pile cylinder 1, and the annular space S
A member 3 that closes the tip side of the pile cylinder 1 is provided in series, and is positioned inside the pile cylinder 1 so that soil remains around the inner circumference of the pile cylinder 1. The tip side of an earth auger 5 whose outer diameter is smaller than the inner diameter of the pile cylinder 1 is passed through the cylinder 2, and the earth auger 5 is ground while rotating the pile cylinder 1 and the earth auger 5 together. After the tip of the pile cylinder 1 reaches the support layer A, the earth auger 5 is pulled up and the pile cylinder 1 is driven to a predetermined depth.

In other words, since the earth auger 5 is much thinner than the inner diameter of the pile cylinder 1 as described above, the excavated earth and sand will remain inside the pile cylinder 1, and the amount of earth discharged to the outside of the cylinder will be reduced. It becomes extremely small. Furthermore, since the closing member 3 is provided, the bottom area of the pile cylinder 1 is increased due to its effect, and furthermore, since the pile cylinder 1 can reach a predetermined depth after reaching the support layer A. Since the insertion is done by driving, the ground around and below the cylinder 1 will be compressed and hardened.Furthermore, if driving is performed with a large base area, the area of the ground below the cylinder that will be compressively hardened will be As a result, even if a large load is applied to the pile from above or from the side, it will be firmly supported by the large pile bottom area and the hard ground around and below. or,
When the tip of the earth auger is supported by the cylindrical body 2, displacement due to the thrust resistance of the earth auger 5 can be prevented, and the insertion direction of the pile cylindrical body 1 can be reliably aligned in the desired direction. Until the pile cylinder 1 reaches the support layer A, the pile cylinder 1 is rotated and the earth auger 5 is used to suppress noise and vibration as much as possible.
It has become possible to efficiently construct piles with high support strength and the desired orientation from the standpoint of soil removal.

[Brief explanation of the drawing]

The drawings show an embodiment of the method for constructing an underground pile according to the present invention, and FIG. 1 is a sectional view of the tip of the pile cylinder, and FIG.
The figure is a cross-sectional view taken along the arrow in FIG. 1, and FIGS. 3 to 6 are explanatory diagrams showing the construction procedure. DESCRIPTION OF SYMBOLS 1... Cylindrical body for piles, 2... Cylindrical body, 3... Closure member, 5...
Earth Ogre, A...Support layer.

Claims (1)

[Claims] 1 The pile cylinder 1 is attached to the tip side of the underground pile cylinder 1.
A cylinder 2 having a concentric or almost concentric shape is inserted and connected in a state where an annular space S is formed between this cylinder 2 and the pile cylinder 1, and the annular space S
A member 3 that closes the tip side of the pile cylinder 1 is provided in series, and is positioned inside the pile cylinder 1 so that soil remains around the inner circumference of the pile cylinder 1. The tip side of an earth auger 5 whose outer diameter is smaller than the inner diameter of the pile cylinder 1 is passed through the cylinder 2, and the earth auger 5 is ground while rotating the pile cylinder 1 and the earth auger 5 together. After the tip of the pile cylinder 1 reaches the support layer A, the earth auger 5 is pulled up and the pile cylinder 1 is driven to a predetermined depth. How to build.