JPH0542526B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a construction method in which a casing is press-fitted into gravelly ground such as a gravel layer or a crushed stone layer, and then piles are erected.

<Prior Art> For example, when reinforcing a road bed that has been compacted with crushed stone or the like by driving foundation piles into it, it is extremely difficult to drive the piles directly into the road bed.

Therefore, a method is generally adopted in which piles are driven into the roadbed after drilling holes therein.

<Problems to be Solved by the Present Invention> The following problems exist in the above-described conventional technique for drilling into gravelly ground.

(b) Even if a hole is drilled with an auger, etc., it is difficult for crushed stone to stand on its own, so if the auger is removed, the hole wall collapses and the hole is blocked, making it extremely difficult to drive piles.

(b) When constructing cast-in-place piles to prevent collapse of soft ground that is difficult to stand on its own, there is a method of using casing.

However, when conventional casings are used for press-fitting into gravel ground, the press-fitting efficiency of the casing is extremely low and the construction period becomes long.

<Objective of the present invention> An object of the present invention is to provide a method for efficiently press-fitting a casing into gravel ground and constructing a pile.

<Structure of the Present Invention> A method for constructing a pile according to the present invention will be described using, as an example, a case in which a casing is press-fitted into a roadbed compacted with crushed stone or the like.

First, the press-fitting device will be explained.

<A> Press-fit device As shown in FIG. 1, the press-fit device is composed of a casing 1 and a cap 2 detachably attached to the upper end of the casing 1.

<B> Casing The casing 1 is a hollow cylinder having a certain length.

[Structure of tip of casing] A plurality of bits 11 are provided protruding from the tip of the casing 1.

The bit 11 is attached so as to protrude from the outer peripheral surface of the casing 1, and the shape of the bit 11 is similar to that of the casing 1.
It is formed so that it is inclined in the direction opposite to the direction of rotation.

Furthermore, a plurality of screw blades 12 are protruded from the outer periphery of the distal end of the casing 1 and extend in a spiral shape from the distal end toward the proximal end.

The screw blade 12 can be provided over the entire area of the cylinder, but as shown in the figure, it is formed over a certain length near the outer periphery of the tip of the cylinder in which the bit 11 is provided.

Each screw blade 12 is attached to the casing 1 by welding a low-height steel plate or the like.

Further, the protrusion length of the screw blade 12 is selected depending on the gravel ground.

[Structure on the base end side of the casing] A cap 2 is provided on the outer periphery of the base end side of the casing 1.
An appropriate number of brackets 13 are provided for attaching.

The bracket 13 is composed of two plates having bolt holes, and these two opposing plates are fixed to the casing 1 as a set.

<C> Cap The cap 2 is a member for transmitting the rotational force from the rotational drive device to the casing 1.

Specifically, for example, as shown in FIG. 1, a ceiling plate 22 is fixed to the upper opening of the cylindrical portion 21.

A rod 23 made of a polygonal column or the like is provided protruding from the center of the top plate 22.

Further, a plate-shaped connecting arm 24 is attached to the outer periphery of the cylindrical portion 21 along the axial direction.

The connecting arm 24 connects to the bracket 1 of the casing 1.
Install it according to the installation position in step 3.

A bolt hole is provided on the free end side of each connecting arm 24.

Further, a reinforcing plate may be attached inside the cylindrical portion 21 in some cases.

[Direction of attaching and detaching the cap] When attaching the cap 2, place the cap 2 having the above structure on the base end side of the casing 1,
Bolts are inserted into both bolt holes of the bracket 13 and the connecting arm 24 located within this bracket to fix it.

When removing the cap 2, the cap 2 can be removed from the casing 1 by simply removing the bolts.

Next, a method of press-fitting the casing 1 will be explained.

<1> Rotation press-fitting of the casing (Figures 2 and 3) The casing 1 with the cap 2 attached is set at the position to be press-fitted, and the casing 1 is press-fitted into the trackbed while being rotated.

Since the casing 1 does not have earth removal means, drilling progresses while pushing away crushed stones etc. with the tip bit 11.

Further, the rotation of the screw blade 12 generates a driving force for press-fitting the casing 1.

As a result, the press-fitting of the casing 1 progresses with crushed stones and the like taken into the casing 1.

Casing 1 continues to be press-fitted until it penetrates the gravel ground and reaches the foundation ground.

<2> Drilling with an auger (Fig. 4) Once the casing 1 is press-fitted to a predetermined depth, the rotation of the casing 1 is stopped.

Subsequently, the cap 2 is removed from the casing 1.

An auger screw 3 is placed in the upper part of the casing 1 to discharge crushed stones and the like inside the casing 1.

Since the casing 1 holds down the entire area of the gravel ground such as crushed stone, there is no fear that the gravel ground will collapse as the drilling by the auger screw 3 progresses.

<3> Inserting the pile (Fig. 5) After drilling the hole to a predetermined depth with the Augus Creu 3, remove the August Creu 3 from the hole, leaving the casing 1 behind.

Even after the auger screw 3 is removed, the gravel ground is held down by the casing 1, so collapse of the gravel ground is suppressed.

Next, a foundation pile 4 made of H-shaped steel or the like is inserted into the drilled hole to a predetermined depth.

<4> Removal of the casing Attach the cap 2 to the base end of the casing 1, and remove the casing 1 by applying rotation in the opposite direction to when the casing 1 was press-fitted.

Finally, the hole into which the foundation pile 4 was inserted is backfilled to complete the work.

<Effects> Since the present invention is as explained above, the following effects can be obtained.

(b) Rather than simply rotating and press-fitting a cylindrical body with a bit at the tip, the casing is press-fitted into the screw blade by applying rotational force to the casing, which has a screw blade protruding from the outer periphery of the tip of the cylindrical body. Propulsive force is generated.

Therefore, the casing can be easily press-fitted even in a gravel layer, crushed stone layer, etc.

(b) Processing is easy because the bit and screw blade are simply attached to the tip of the cylindrical body by welding or the like.

Therefore, it is also possible to use an existing casing.

(c) The casing can be press-fitted not only into gravel ground but also into ground with normal geology.

(d) When the cap is attached to the casing,
Transmits the rotational force of the rotational drive source to the casing, allowing the casing to be press-fitted and pulled out.

Furthermore, by removing the cap from the casing, the auger screw and pile can be inserted, and the casing can prevent the hole wall from collapsing during work.

Therefore, reliable pile construction is possible.

[Brief explanation of the drawing]

Figure 1: Perspective explanatory view of press-fitting device, Figures 2 to 5:
An explanatory diagram of the work process.

Claims (1)

[Scope of Claims] 1. A casing having a bit at the tip and a plurality of linear screw blades along the outer periphery; A cap with a part that engages with the casing is detachably attached, and the casing is press-fitted into the gravel ground to a specified depth while applying rotational force to the casing using this cap.The cap is then removed and the auger screw is inserted into the casing. Insert the casing, excavate the ground inside the casing, then erect the pile in the excavated space inside the casing, attach the cap to the base end of the casing again, pull out the casing while rotating it, and finally backfill the pile to complete the work. How to install piles.