JP2879373B2 - Guide pipe for compacted pile - Google Patents

Description

The present invention relates to a cast-in-place concrete pile, a continuous underground wall,
In the construction of precast concrete piles (embedded piles), etc., guide pipes used to penetrate compacted piles into the tip ground (hole bottom ground) to enhance their tip bearing capacity, The present invention relates to a guide pipe used by using a reinforcing bar such as a cast-in-place concrete pile, a continuous underground wall, or using a hollow portion of a pre-made pile.

Conventional technology Conventionally, in the construction of cast-in-place concrete piles and the like, it has been a problem that the tip support force is reduced due to loosening of the tip ground due to excavation, and in the construction method described in JP-A-63-312419, A method has been proposed in which after the cast concrete has developed strength, a compacted pile is penetrated into the tip ground, and the tip ground is compacted to increase the bearing capacity.

Problems to be solved by the present invention In order to penetrate the compacted pile into the tip ground, in the case of cast-in-place concrete piles or continuous underground walls, a special long guide pipe that reaches the ground is necessary, but in practice The problem is how to install this guide pipe. In the case of ready-made concrete piles (embedded piles)
Although the hollow part can be used for the guide pipe, there is a problem in what means and manner in which the hollow part of the existing pile is actually used effectively.

In addition, at least the following four functions are required for the guide pipe, particularly at the distal end.

1) Until the body such as cast-in-place concrete pile is completed, it can withstand the muddy water pressure and concrete pressure in the excavation hole to prevent the backflow (penetration), and when it reaches the ground surface at the tip (bottom of the excavation hole) The tip opening must be closed water-tight with enough strength not to break.

2) When the compaction hole comes down, it has a centering function to correct the eccentricity.

3) When the compacted pile penetrates into the tip ground,
The closure of the tip opening can be easily broken.

4) The backflow (flooding) of excavated muddy water, groundwater, etc. is small even after the breakage of the blockage due to the penetration of the compaction pile, and therefore, it is possible to prevent the disturbance of the ground at the tip and the deterioration of the quality of cement milk which is filled in the guide pipe.

However, conventionally, a guide pipe that solves the above-described problems or that satisfies the demand for advanced functions has not been developed.

Means for Solving the Problems As means for solving the above-mentioned problems of the prior art, a guide pipe for a compacted pile according to the present invention is, as shown in the embodiment of the drawings, a cast-in-place concrete pile or the like. A guide pipe for guiding the compacted pile 2 penetrating into the excavation hole bottom ground 7 (hereinafter referred to as the tip ground) from the ground to the hole bottom. A plurality of cut grooves 15 are formed in the lid plate 12 in a radial arrangement from the center, and the lid plate 12 is configured to be able to be broken by the compaction pile 2; B) The guide pipes 1 are integrally attached to a cast-in-place concrete pile 3 or a reinforcing steel bar 4 of a continuous underground wall in a required arrangement by a required number (FIG. 1).

The guide pipe for a compacted pile according to the present invention also has the following features: a) In the hollow portion 5a at the distal end of the existing pile 5 having a hollow structure, the outer diameter of the compacted pile 2 is substantially the same as the outer diameter of the compacted pile 2 in a concentric arrangement with the hollow portion 5a. A guide pipe 11 having an inner diameter is installed, and the upper end of the guide pipe 11 is expanded in a funnel shape and is in contact with the inner surface of the hollow part. B) The tip of the guide pipe 11 is watertight with a lid plate 12. The cover plate 12 is formed with a plurality of cut grooves 15... Arranged radially from the center, and the cover plate 12 is configured to be able to be broken by the compaction pile 2. (Figs. 3 and 4).

Furthermore, the guide pipe for the compacted pile according to the present invention includes: a) a hollow portion 5a at the tip end of a large-diameter ready-made pile 5 'having a hollow structure.
Inside, a plurality of guide pipes having substantially the same inner diameter as the outer diameter of the compaction pile 2 at a plurality of positions distributed in the cross section of the hollow portion 5a.
Are arranged in parallel with each other, and each of the connecting pipes 6a and 6b is constrained integrally with the existing pile 5 '. The upper end 11a of each guide pipe 11 ... is a compacted pile 2 which has descended in the hollow part 5a. The tip of each guide pipe 11 is water-tightly shielded by a cover plate 12, and the guide plate 11 is radially arranged from the center portion of the guide pipe 11. A plurality of cut grooves 15 are formed, and the cover plate 12 is
(Fig. 5).

Further, in each of the above-mentioned inventions, cut-in grooves 15 are formed in the outer surface of the lid 12, and an inverted conical reinforcing plate is provided between the inner surface of the lid plate 12 and the inner surface of the guide pipe 1 or 11.
13 (Fig. 2 A, B,
C).

The guide pipe 1 (FIG. 1) integrated with the reinforcing bar 4 is simultaneously guided by inserting the reinforcing bar 4 into the excavation hole in a predetermined manner with respect to the cast-in-place concrete pile 3 or the continuous underground wall and the like. The installation of the pipe 1 is performed normally.

Similarly, in the case of using the hollow portion 5a of the existing pile 5 or 5 'as a part of the guide pipe (FIGS. 3 to 5), the existing pile 5 or 5' is embedded along the excavation hole. At the same time, the guide pipe 11 is properly installed.

In addition, the tip opening of the guide pipe 1 or 11 is
, Water, etc., is prevented from flowing back (flooding) into the guide pipe 1 or 11 due to muddy water, groundwater or cast concrete in the borehole.

When the compaction pile 2 inserted into the guide pipe 1 or 11 is strongly pushed down, the cover plate 12 is relatively easily broken in the form of a tulip along the cut grooves 15. To enter. The tip ground 7 (support layer ground) is compacted by the volume of the compacted pile 2 thus penetrated.

Each of the tulips of the lid plate 12 broken in a tulip shape is attached to the outer peripheral surface of the compaction pile 2 due to elasticity inherent to a material such as an iron plate, so that the shielding effect is relatively well maintained. Backflow such as drilling mud and groundwater is suppressed.

Embodiment Next, the illustrated embodiment of the present invention will be described.

The guide pipe 1 shown in FIG. 1 is, for example, a steel cage 4 prepared in the construction of a cast-in-place concrete pile 3.
In addition, three guide pipes 1 (however, the number is not limited to this) are integrally provided at positions allocated by appropriate design in the cross section of the cast-in-place concrete pile 3, and the guide pipes 1 together with the rebar cage 4 are provided. Is installed, and the compaction pile 2 can be guided from the ground to the tip ground 7 (hole bottom ground) by the respective guide pipes 1. Therefore, an iron pipe having an inner diameter (for example, about 32 cm) slightly larger than the outer diameter of the compaction pile 2 is used as the guide pipe 1. As shown in FIGS. 2A and 2B, the opening at the tip end of the guide pipe 1 is watertightly shielded by a cover plate 12 made of an iron plate or the like. Between the inner surface of the cover plate 12 and the inner surface of the guide pipe 1, a reinforcing plate 13 having a tapered angle of about 45 ° and an inverted cone shape is installed.
And the centering correction of the compaction pile 2 inserted in the guide pipe 1 is made possible. Reinforcement plate 13
2A, the guide pipe 1 is reinforced so that the cover plate 12 is not damaged even when the guide pipe 1 is slightly settled into the tip ground 7. In addition, a large number of cut grooves 15 are formed in the cover plate 12 in a radial arrangement from the center as shown in FIG. 2B. As shown in FIG. 2C, details of the cut groove 15 are provided on the outer surface (lower surface) of the cover plate 12 with the thickness t of the cover plate 12.
It is formed as a V-cut groove having a depth a and an opening width b of about 2 × 2 mm with respect to (about 4 mm). Therefore, the cover plate 12 is strong against the pressure from the outside, but relatively weak against the pressure from the inside, and the breakage (so-called knockout) by the compaction pile 2 is relatively easy.

Therefore, when the compaction pile 2 is lowered into the guide pipe 1 which is inserted into the excavation hole together with the rebar cage 4 and is set in such a manner as to land on the tip ground 6 as shown in FIG. Alignment for correcting the eccentricity of the compaction pile 2 is performed by the conical reinforcing plate 13, and the tip of the compaction pile 2 is located substantially at the center of the cover plate 12. When the compaction pile 2 is strongly pushed down, the cover plate 12 is broken along the cut grooves 15..., And the compaction pile 2 enters the tip ground 7. The compacted pile 2 penetrates into the tip ground 7 to a desired depth,
The tip ground 7 is compacted by that volume. After that, the guide pipe 1 is filled with the cement milk which is filled in, and the penetrating state of the compaction pile 2 is fixed. The cover plate 12 is cut into tulips along the radially arranged cut grooves 15 shown in FIG. 2B as the compaction pile 2 penetrates. Since it is calm, the backflow of drilling mud and the like is well suppressed, and the quality deterioration of the filled cement milk and the like is prevented.

The cover plate 12 shown in FIG. 2A is a horizontal flat plate, but is not limited to this. If the center of the cover plate 12 is formed to have a tapered conical shape slightly convex toward the outer surface (lower surface) and the reinforcing plate 3 is provided on the inner surface thereof, a lid having a conical shape convex to the outer surface is formed. The plate 12 has an advantage that the proof stress is large with respect to the excavation mud pressure applied to the outer surface, the cast concrete pressure, and the like. Therefore, if the operation is performed with the conical lid plate 12 having a steeper taper, the reinforcing plate can be omitted.

Other Examples Next, FIG. 3 shows that the outer diameter (about 30 cm) of the compacted pile 2 is concentrically arranged with the hollow part 5a in the hollow part 5a at the tip of the existing concrete pile 5 having a hollow structure. A short guide pipe 11 having substantially the same inner diameter is installed and joined to the tip fitting 10 in a water-tight manner. The tip opening of the guide pipe 11 is shielded by a lid plate 12 in a water-tight manner. The structure used for the guide pipe is shown. The upper half of the guide pipe 11 is enlarged upward in a funnel shape, and is in contact with the inner surface of the hollow portion 5a of the existing pile 5 with a smooth taper. Therefore,
The compacted pile 2 inserted into the hollow portion 5a smoothly enters the guide pipe 11, and the eccentricity correction is performed.

The lid plate 12 that shields the tip of the guide pipe 11 is reinforced by an inverted cone-shaped reinforcing plate 13, and furthermore, a plurality of cut grooves are formed in a radial arrangement to facilitate the breakage by the compacted pile 2 that has entered, This is the same as the first embodiment. This point is also common to the following embodiments.

Next, in the embodiment of FIG. 4, the total length (50 cm) of the compacted pile 2 is shown.
(About 1 m) is installed in the hollow portion 5a of the existing concrete pile 5 in a slightly longer length.

In the embodiment shown in FIG. 5, the outer diameter of the compacted pile 2 (approximately 30
An example is shown in which a large-diameter ready-made concrete pile 5 having a hollow portion 5a having an inner diameter several times larger than about (cm) is used as a part of a guide pipe. That is, in the hollow portion 5a at the tip of the large-diameter ready-made stake 5 ', there are three positions allocated by appropriate design in the cross section of the hollow portion 5a (however, the number of positions is not limited to three). ), Three guide pipes 11 having substantially the same inner diameter as the outer diameter of the compaction pile 2 are arranged in parallel in parallel, and each of the guide pipes 11 is formed by a common connecting plate (or frame) 6a, 6b. ′ And is installed by being restrained by an integral structure. In particular, the connecting plate 6a at the upper end is installed at substantially the same level as the upper end of the guide pipe 11. In addition, since the upper end of the guide pipe 11 is expanded upward in a funnel shape, the compacted pile 2 inserted into the large-diameter hollow portion 5a and descending is smoothly moved from the funnel-shaped inlet to each guide pipe 11.
Enter inside. The connecting plate 6b at the lower end is a metal fitting at the tip of the existing pile 5 '.
10 and watertight.

Advantageous Effects of the Present Invention The guide pipe for compacted pile according to the present invention is installed together with the reinforcing steel 4 such as the cast-in-place concrete pile 3 or the continuous underground wall, or is installed tightly with the embedded pile 5 or 5 ′. Therefore, the workability is good, the installation can be performed reliably and accurately, and the implementation is extremely easy. In addition, the cover plate 12 which shields the opening at the tip of the guide pipe 1 or 11 has sufficient strength to withstand the pressure of excavated muddy water or the pressure of cast concrete, has the strength not to be damaged even when it is settled on the bottom of the excavation hole, When the compacted pile 2 penetrates, it can be easily broken along the cut grooves 5 to ensure penetration into the tip ground 7, and each piece of the cover plate 12 broken like a tulip along the cut grooves 15 Is attached to the outer peripheral surface of the compaction pile 2 to prevent backflow such as drilling mud and the like, and to prevent disturbance of the tip ground 7 and deterioration of the quality of the cement milk, etc., so that the tip ground 7 is supported by compaction. It has an excellent effect on increasing power.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a guide pipe according to a first embodiment of the present invention, FIGS. 2A, 2B, and 2C are a vertical section and a bottom view of a cover plate portion and an enlarged sectional view of a cut groove, and FIGS. FIG. 5 is a sectional view showing a different embodiment of the present invention. 1,11… Guide pipe, 2… Compacted pile 12 …… Cover plate, 5… Cut groove 4 …… Reinforced basket, 5,5 ′… Precast concrete pile 5a …… Hollow section, 6a, 6b… ... Connecting plate 13 ... Reinforcing plate

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomio Tsuchiya 2-5-114 Minamisuna, Koto-ku, Tokyo Inside Takenaka Corporation Technical Research Institute Co., Ltd. (72) Yoshihiko Kurita 2-5-1-14 Minamisuna, Koto-ku, Tokyo No. Takenaka Corporation Technical Research Institute Co., Ltd. (72) Inventor Takuhei Fukuhara 8-21-1, Ginza, Chuo-ku, Tokyo Co., Ltd. Takenaka Civil Engineering Co., Ltd. (56) References JP-A-63-321419 (JP, A) ( 58) Fields surveyed (Int.Cl. ⁶ , DB name) E02D 5 / 62,5 / 34 E02D 5 / 20,3 / 08

Claims (4)

(57) [Claims] 1. A guide pipe for guiding a compacted pile, such as a cast-in-place concrete pile, which penetrates into the bottom of an excavation hole from the ground to the bottom of the hole, a) The tip of the guide pipe is watertight with a lid plate. The cover plate is provided with a plurality of cut grooves formed radially from the center, and the cover plate is configured to be able to be broken by a compaction pile. B) The guide pipe is Guide pipes for compacted piles, each of which is integrally attached to the required number of cast piles or reinforcing bars of continuous underground walls in the required arrangement. 2. A guide pipe having an outer diameter substantially equal to the outer diameter of the compacted pile, which is concentrically arranged with the hollow portion, is installed in a hollow portion at the tip of the existing pile having a hollow structure. The diameter of the guide pipe should be expanded to be in contact with the inner surface of the hollow part. B) The tip of the guide pipe is water-tightly shielded by a cover plate. A guide pipe for a compacted pile, characterized in that a cut groove is formed and the cover plate is configured to be breakable by the compacted pile. 3. A pile having a hollow structure having a large diameter and having a diameter substantially equal to the outer diameter and the outer diameter of the compacted pile at a plurality of positions distributed in a cross section of the hollow portion at the tip of the existing pile. The guide pipes are arranged side by side, each of them is constrained in an integrated structure with the existing pile by the connecting plate, and the upper end of each guide pipe is tapered to guide the compacted pile that has descended the hollow part. B) the tip of each of the guide pipes is water-tightly shielded by a cover plate, and the cover plate has a plurality of cut grooves formed radially from the center; The cover pipe is configured to be able to be broken by the compaction pile, and the guide pipe for the compaction pile, respectively. 4. A notch groove is formed on an outer surface of the cover plate, and an inverted conical reinforcing plate is provided between an inner surface of the cover plate and an inner surface of the guide pipe. 4. A guide pipe for a compaction pile according to any one of the first, second, and third aspects.