JPS6250519A - Protector for head of concrete pile - Google Patents

Abstract

PURPOSE:To transmit striking forces to concrete piles with good efficiency by providing a bottom plate laminated with a plurality of holding plates to hold a supporter, a top plate, and a device piercing the top plate, the bottom plate, the supporting plate, and the holding plates and tensing them. CONSTITUTION:A protector 15 for the head of concrete pile is set between a pile hammer 16 and a concrete pile 14. A cap 11 is set on the lower part of the hammer portion 9, and a top plate 1 is contacted with the bottom face and held on the supporter 7 with non-elastic holding plates 6. PC steel bars 3 are tensed by as given force to press the top plate 1 on the bottom plate 2, and the supporter 7 is coupled with the holding plates 6. The striking force of a pile hammer can thus be transmitted without being damaged, and the concrete pile can be protected by adjusting the buffering and contracting amount.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a concrete pile head protection device for protecting the head of a concrete pile when driving the pile.

[Conventional technology]

Generally, when concrete piles are driven into soft ground or by punching through an intermediate layer (relatively hard layer with a high N value), tensile strain called the slug phenomenon occurs in the slab, resulting in ring-shaped cracks. , crushing failure of the antibody often occurs.

Therefore, conventionally, concrete piles with large pre-stresses are used.

It has become uneconomical.

Next, as pollution has become a social issue in recent years, pre-boring (excavation with a spiral auger) is used during concrete pile construction.
Combined impact construction methods are becoming more common.

However, with this construction method, when a concrete pile is driven into an excavated hole and struck, the ground at the tip of the pile has been loosened by the excavation, so there is no resistance and the penetration is sudden, resulting in the concrete pile's direction not being determined and the impact being applied. Tensile waves and bends act on the
Antibody breakage accidents are likely to occur.

Furthermore, when the tip of the pile penetrates into the support layer and the falling height of the pile hammer increases, the impact force acting on the pile head also increases, and along with this, a tensile force in the circumferential direction is generated due to the Poisson effect of the material.

For this reason, the PC steel rod placed in the antibody has a cross-sectional defect in the apparent thickness of the concrete wall, and vertical cracks occur along the PC steel rod.

In particular, this phenomenon often occurs when the pile diameter is large and a large prestress is introduced and the amount of glue bounce during driving is small.

Therefore, in order to solve the above-mentioned problems, r
Method and device for suppressing shock waves during pile driving speed
No. 85032) was proposed.

[Problem that the invention seeks to solve]

However, since this conventional device uses a spring as a buffering means, there are problems in that impact energy is absorbed, the impact force of the pile hammer is impaired, and the penetration speed of the antibody is slow.

Furthermore, since only a predetermined spring is used, the amount of cushioning shrinkage is specified, resulting in a lack of versatility.Φ The present invention was proposed to solve the above-mentioned problems, and the impact force of the pile hammer can be reduced. To provide a highly versatile concrete pile pile head protection device capable of transmitting impact force to a concrete pile without damaging it and easily adjusting the amount of buffer shrinkage.

[Means for solving problems]

The present invention was proposed in order to solve the above-mentioned problems, and includes a support body (7) having a flat plate shape and made of an elastic body, and an inelastic body that fits and holds the support body (7) on the upper surface. a retaining plate (6) that fits and holds the support (7);
) are laminated in pairs, and the top layer support (
7) The top plate (1) placed a on the upper surface, penetrates the top plate (1), the bottom plate (2), the plurality of pairs of supports (7), and the retaining plate (6), and tightens the top plate. A pile cap protection device for a concrete pile characterized by comprising a tensioning means (3) for pressing (1) against a bottom plate (2) and locking the support (7) and the retaining plate (6). It is.

[Effect]

Next, to explain the present invention in detail, when the present invention is used, as shown in the compressive load-shrinkage amount curve as shown in FIG. Since this has an elastic contraction waveform, this deformation softens the shock wave and disperses the stress, thereby preventing vertical cracking of the antibody.

Furthermore, in order to obtain reliable support force for concrete piles, it is necessary to transmit a predetermined impact force to the antibodies.

In the present invention, when the second inflection point 21 is exceeded, the support body 7 made of an elastic body contracts, and the retaining plates 6 made of, for example, iron come into contact with each other, so that the impact force of the pile hammer can be transmitted without loss.

Furthermore, the amount of cushioning shrinkage can be adjusted by increasing or decreasing the number of laminated holding plates 6 that fit and hold the support body 7 on the upper surface, thereby providing high versatility.

〔Example〕

Hereinafter, the present invention will be described based on embodiments thereof with reference to the drawings.

First, as shown in FIG. 4, the concrete pile head protection device 15 of this embodiment is installed between the pile hammer 16 and the concrete pile 14, and is shown in more detail in FIG.

A cap 11 is attached to the lower part of the hammer part 9 that slides up and down inside the cylindrical part lO of the pile hammer 16 via a buffering tree 12.
will be placed.

The top plate 1 constituting this embodiment, which is also shown in FIG. 2, which is a view taken along the line A-A&1 in FIG. 1, comes into contact with the bottom surface of the cap 11.

Next, the support body 7 has a substantially flat plate shape and is made of an elastic material such as synthetic rubber.

A holding plate 6 made of iron, which is a non-elastic material, fits and holds the support body 7 on its upper surface.

Here, it goes without saying that the inelastic material of the holding plate 6 is not limited to iron.

The bottom plate 2 has a cylindrical portion 2a that is open to the left, and a holding plate 6 that fits and holds the support 7 on the bottom plate 2 within the cylindrical portion 2a.
are stacked in pairs.

The bottom plate 2 may not have a structure having the cylindrical portion 2a, but may simply have a structure in which the support body 7 and the holding plate 6 are laminated on the bottom plate 2.

Here, the top plate 1 is placed a on the upper surface of the uppermost support 7.

The PC steel rod 3, which is a tensioning means, has a top plate 1, a bottom plate 2, and a support 7.
and the holding plate 6.

The upper and lower ends of this PC steel bar 3 are threaded and tensioned by nuts 4.4.

By tensioning the PC steel rod 3 with a required force, the top plate 1 is pressed against the bottom plate 2, and the support body 7 and the retaining plate 6 are locked.

Here, the tensioning means is not limited to the PC steel rod 3, and other bolts may be used.

Further, the bottom plate 2 is fastened to the cap 8 by a set screw 5.

The bottom plate 2 and the cap 8 may be constructed integrally.

The head of a concrete pile 14 is located at the bottom of this cap 8 with a buffer tree 13 interposed therebetween.

In this embodiment, four holding plates 6 that fit and hold the support body 7 are stacked, and the amount of shrinkage is as shown in FIG. 3, but the amount of shrinkage can be increased or decreased as appropriate. 2
g1m and highly versatile.

〔Effect of the invention〕

As explained above, the present invention can transmit the impact force of the pile hammer without impairing it, and furthermore, the amount of buffer shrinkage can be adjusted, so it has high versatility and has the effect of effectively protecting concrete piles.

[Brief explanation of the drawing]

Fig. 1 is a B-BiQ sectional view in Fig. 2 of an embodiment of the present invention applied to the head of a concrete pile, Fig. 2 is a view taken along the line A-A in Fig. 1, and Fig. 3 is a sectional view taken along line A-A in Fig. 1. FIG. 4 is an explanatory diagram of the relationship between the compressive load when struck by a pile hammer and the amount of shrinkage of this embodiment, and FIG. 4 is an overall schematic diagram of this embodiment installed between a pile hammer and a concrete pile. l... Top plate 2... Bottom plate 2a... Cylindrical part 3... PC steel bar 4... Nut 6... Protective plate 7... Support body 8... Cap 14... Concrete Pile 15... Pile head protection device for concrete pile 16... Pile hammer

Claims (1)

[Scope of Claims] 1. A substantially flat support body (7) made of an elastic body, a holding plate (6) made of an inelastic body that fits and holds the support body (7) on its upper surface, and the support body A bottom plate (2) on which a plurality of pairs of holding plates (6) are stacked to fit and hold (7), a top plate (1) placed on the upper surface of the uppermost layer support (7), and a top plate (1) and the bottom plate (2), the plurality of pairs of supports (7), and the holding plate (6), and by tension, the top plate (1) is pressed against the bottom plate (2), and the support (
7) and a tensioning means (3) for locking a retaining plate (6).