JPS5938375B2 - How to bury hollow piles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for burying hollow piles, such as concrete piles.

One of the conventional methods of this type is the Nakahori hammer method.

As shown in Fig. 1, this method involves inserting an earth auger 3 with a spiral screw into the pile 1, erecting it at the burial site, and inserting the pile 1 into the soil while digging with this auger. When the tip reaches the predetermined stopping depth in the support layer 11, the pre-digging is stopped. Next, after hitting the pile 1 lightly with a Monken etc., pull up the auger 3, and then move the pile 1 with a hollow Monken or diesel The pile is stopped with a hammer, and the amount of pile settlement is finally measured and confirmed to complete the construction.In particular, during the stopping, soil entered the pile and was forced in, which caused vertical cracks in pile 1. Moreover, since the pile 1 is supported only by its annular cross section, its supporting force may inevitably become small.

Another method is the Nakahori press-in method.

As shown in Fig. 2, this method involves installing a folding head 5 at the tip of the auger 3, inserting it into the pile 1,
While the pile is in the erected state, the head 5 is expanded to make it into the excavation state, and the pile 1 is inserted into the soil while rotating the auger 3. When the tip reaches the predetermined stopping depth in the support layer 11, Start pouring cement milk for root hardening, and stir the cement milk by moving it up and down several times.
After this injection is completed, the auger is pulled up and the pile 1 is pushed in with a press-fitting device such as a hydraulic pushing device to complete the construction.
The cement milk is easily washed away by groundwater during injection, and it is difficult to confirm from the ground whether the cement milk has formed into a spherical shape as shown in Figure 2. Since this method is used, the diameter of the buried pile is naturally restricted, and there is a possibility that it cannot be applied to small-diameter piles.

This invention solves the above-mentioned drawbacks, and
It is an object of the present invention to provide a method for burying hollow piles that has a large supporting force and is independent of the outside diameter of the pile.

An embodiment of the present invention will be described below with reference to the drawings.

That is, in FIGS. 3 to 5, a reinforcing ring 2 is provided at the end of a cylindrical hollow concrete pile 1, and an earth auger 3 is inserted into the pile.

As is well known, this auger has a spiral screw 4 on its outer periphery.

The auger head 5 is formed into an umbrella shape, and has an outer diameter equal to or larger than the inner diameter of the pile 1, and has a plurality of digging blades 6, 6 on its lower surface.

A pair of retaining pieces 7, 7 are drilled at the tip of the auger, and a pair of retaining pieces 7, 7 are provided on the upper surface of the head 5 to rotate the auger in the first rotational force direction, that is, in the direction of the excavation rotational force of the head 5. When engaged with the engaging pieces 7, 7 and rotated in the second rotational force direction opposite to the first rotating direction, the engaging pieces 7, 7
Engagement notches 8, 8 are provided to release the engagement with the tag.These notches and the engagement pieces 7, 7 form an engagement portion.

Next, the embedding process of this invention will be explained with reference to FIG.

First, a shallow hole 10 is prepared in advance at an excavation point, and a head 5 having a diameter equal to or larger than the inner diameter of the pile 1 is installed in this hole.

- Insert the auger 3 into the pile 1 and erect it at the burial point, that is, directly above the head 5 (Fig. 6 A)
.

In this state, when the auger 3 is rotated in the first rotational force direction, that is, in the positive rotational force direction in which the head 5 moves forward, the engagement pieces 7, 7 of the auger 3 engage with the engagement notches 8, 8 of the head 5. ,
Both are connected to each other.

In this state, the lower end of the pile 1 is brought into contact with the head 5 (Figure 6).

Next, the auger 3 is rotated in the first rotational force direction while applying a predetermined pressure to the auger 3 and the pile 1, for example, by a hydraulic pushing device.

Then, the head 5 and the pile 1 are penetrated into the soil to the support layer 11 while maintaining a predetermined distance l between them (FIG. 6C).

Next, when the auger 3 is rotated in the opposite direction, that is, in the second direction, the engaging pieces 7, 7 of the auger 3 are disengaged from the notches 8, 8 of the head 5, that is, the head 5
The engagement with the auger 3 is released, and the head 5 is left behind in the support layer 11.

You will be able to do it.

In this state, there is a predetermined distance between the lower end of the pile 1 and the head 5, so when pressure is applied from the upper end of the pile 1 by tapping or press-fitting, the lower end collides with the head 5, as shown in Figure 6. ), which serves as a support member for the pile 1.

Next, pressure is applied from the upper end of the pile 1 by tapping or press-fitting to further penetrate the pile 1, and after this, the auger 3 is pulled out from inside the pile 1 (see Fig. 6).
Note that the tip of the pile 1 can be hardened with cement milk if necessary.

In addition, when excavating with an auger, water or air is introduced into the hollow part of the auger 3, and is injected into the soil from the spout 12 (see Figures 3 to 5) provided in the head 5. , it is possible to improve the efficiency of excavation and removal of the earth and sand.

Further, it is optimal that the outer diameter of the head 5 is slightly larger than the outer diameter of the pile 1, but based on the results of embedding piles with an outer diameter of 350 to 600 layers using the method of the present invention, etc. It was found that construction is possible as long as the outer diameter of the head 5 is equal to or larger than the inner diameter of the pile 1.

This invention does not use a friction cutter like the Nakahori hammer method, so there is no risk of vertical cracking in the pile during the final stop, and the head is used with the auger inserted into the pile.

Because it is attached to the tip of the auger, it is possible to construct piles even if the diameter of the pile is relatively small, for example, 450% or less.Moreover, since the head is removably engaged with the auger, the pile The entire cross-sectional area of the head is supported by the head, which has the advantage that its supporting force is extremely large and its work is extremely easy.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing a method for burying hollow piles using the conventional hollow-moat impact method, Fig. 2 is a cross-sectional view showing a method for burying hollow piles using the conventional hollow-moat press-in method, and Figs. 3 is a front sectional view of the main part, FIG. 4 is a bottom view of the head, FIG. 5 is a plan view thereof, and FIG.
The figure is a sectional view showing the construction process. In the drawings, the same reference numerals indicate the same or equivalent parts. 1...Pile, 2...Reinforcement ring, 3...
...Auger, 4...Spiral screw, 5...Head, 6゜6...Drilling blade, 7,7...Engagement piece, 8, 8... Engagement notch portion, 10... Hole, 11... Support layer.

Claims (1)

[Claims] 1 Attach an auger head having a diameter equal to or greater than the inner diameter of the pile to the protruding lower end of the earth auger inserted into the hollow pile, rotate the auger, and place the head and pile in the soil. After penetrating to a predetermined depth while maintaining a predetermined distance between them, the auger and the head are disengaged, a light tap or pressure is applied to the pile to abut the lower end of the pile against the head, and A method for burying hollow piles, characterized by applying light tapping or pressure to the piles.