JP2958717B2 - Guide pipe for compacted pile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a cast-in-place concrete pile, a continuous underground wall, or an embedded pile using a ready-made concrete pile. And a guide pipe used to penetrate into the ground.

[0002]

2. Description of the Related Art Conventionally, in the construction of cast-in-place concrete piles and the like, there has been a problem that excavation loosens the tip ground and lowers the tip supporting force.
In the construction method described in Japanese Patent Publication No. 9, after the cast concrete has developed strength, the compacted pile penetrates into the tip ground,
A construction method has been proposed in which the tip ground is compacted to increase the bearing capacity.

[0003]

The above-mentioned known construction method is a method in which the compacted pile penetrates into the tip ground after the stiffness of the skeletal concrete has developed, so that only the curing period of the stiffened concrete is required. There is a disadvantage that the construction period is long.
On the other hand, in order to prevent the poured concrete from flowing back into the guide pipe and solidifying, the opening at the tip of the guide pipe is tightly sealed with a lid plate that is strong enough to be broken by a pile. (Japanese Patent Application No. 2-341238) has been developed. However, the processing of the cover plate is troublesome and the production cost is high. In addition, when a hollow guide pipe with a closed end is inserted into a borehole to attempt to sink it, buoyancy due to muddy water acts as resistance. In particular, in the construction of embedded piles using ready-made concrete piles, since the pre-made concrete piles are built while compressing muddy water etc. in the drilling hole like a piston, water pressure etc. greater than buoyancy acts as resistance. There is a problem that makes the work difficult.

[0004] Therefore, a guide pipe b attached to a ready-made stake a, as shown in FIG. 6, has been developed in which the front end opening is entirely open (Japanese Patent Application No. 2-407579). But,
With this configuration, the earth removal c generated when the compaction pile d penetrates
Enter the guide pipe b (see FIG. 6). This earth removal c deteriorates the quality of the cement milk which is later packed in the guide pipe b, and when the load of the allowable limit is applied to the main body pile, the deteriorated cement milk becomes far before the allowable load. There is a problem of being destroyed and lowering the bearing capacity, which is a problem to be solved.

[0005]

As a means for solving the above-mentioned problems of the prior art, a guide pipe for a compaction pile according to the present invention is, as shown in the drawings, an embodiment.
A guide pipe for guiding the compacted pile 6 penetrating into the bottom of the excavation hole such as a cast-in-place concrete pile from the ground to the bottom of the hole, having an inner diameter slightly larger than the outer diameter of the compacted pile 6, A soil return plate 10 that is formed of an iron pipe or the like having a length equal to or greater than the depth of the hole 2 or the like and that shields the opening at the tip of the pipe 4 is installed. 6, a plurality of cut grooves 9 are formed radially from the center, and the soil return plate 10 is formed by the compaction pile 6 to form the cut grooves 9. (See FIGS. 1 and 2).

In the guide pipe of the present invention, a short guide pipe 4 ′ having an inner diameter slightly larger than the outer diameter of the compacted pile 6 is concentric with the hollow portion 14 a of the ready-made pile 14 at the end fitting 13 of the hollow pile 14. The guide pipe 4 'has a tip 4b protruding from the tip fitting 13 by a slight length h, and an earth return plate 10 for shielding the tip opening of the guide pipe 4' is installed. The soil return plate 10 has a through hole 11 having a diameter substantially equal to the diameter of the tip of the compaction pile 6 at the center and a plurality of cut grooves 9 formed radially from the center. Ori, backplate 1
No. 0 is characterized in that it can be broken along the cut groove 9 by the compaction pile 6 (see FIGS. 4A and 4B).

In each of the above-mentioned inventions, the cut groove 9 is formed on the outer side surface (lower surface) of the earth return plate 10, and the guide pipe 4 is required for the cast-in-place concrete pile 2 or the reinforcing bar 3 of the continuous underground wall. 3 and the upper end of the guide pipe 4 'is enlarged in a funnel shape (FIGS. 4A and 4B). Further, the guide pipe according to the present invention includes: a) The hollow pipe 5 has a hollow structure, and the compacted pile 5 is provided at a plurality of positions distributed in the cross section of the hollow pile 5a. A plurality of guide pipes 4 'each having a slightly larger inner diameter are arranged in parallel, each being restrained by a connecting plate 8a, 8b in an integrated structure with the ready-made stake 5, and the upper end of each guide pipe 4' is formed in a hollow portion. Is formed in a funnel shape having a taper suitable for guiding the compacted pile that has descended. B) The opening at the tip end of each of the guide pipes 4 'is shielded by a soil return plate, and A through hole having substantially the same inner diameter as the tip diameter of the compaction pile 6 is provided in the portion, and a plurality of cut grooves are formed radially from the central portion. It is also characterized by being breakable along 5).

[0008]

When the guide pipe 4 is laid alone or together with the rebar cage 3 in the excavation hole, or when the ready-made pile 5 or 14 is built in the excavation hole, the muddy water filled in the excavation hole is returned to the soil. There is no appreciable resistance because the through-hole 11 of the plate 10 flows freely. The upward discharge that occurs when the compaction pile 6 penetrates into the tip ground is reliably blocked by the earth return plate 10 and entry into the guide pipe 4 or 4 'is prevented.

The soil return plate 10 is broken as the compaction pile 6 penetrates, but the fracture progresses along the radially arranged cut groove 9 like a petal of a tulip, so to speak. (FIG. 4B), so that the effect of preventing the intrusion of the earth removal is still maintained. The tip 4b of the guide pipe 4 'is made of a ready-made pile 5 or 14.
Of the guide pipe 13 slightly protrudes from the position of the front end fitting 13 into the ground. Accordingly, the earth discharging C shown in FIG. 6 is prevented from sneaking into the space e immediately below the tip of the pile to lower the tip supporting force.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
The guide pipe 4 shown in FIGS. 1 and 2 is for guiding the compaction pile 6 from the ground to the tip ground (hole bottom ground) in the construction of a cast-in-place concrete pile, for example. An iron tube having an inner diameter several centimeters larger than the outer diameter (usually about 10 to 60 cm) and having a length equal to or greater than the depth of the pile hole is used. The opening at the tip end of the guide pipe 4 is shielded by an earth return plate 10 made of an iron plate. A through hole 11 having a diameter equal to or slightly larger than the tip diameter (typically about 5 to 30 cm) of the compaction pile 6 is provided in the center of the earth return plate 10. In addition, a large number of cut grooves 9 are formed in the soil return plate 10 in a radial arrangement from the center thereof (FIG. 2). The cut groove 9 is a
On the outside surface (lower surface) of the same, the thickness of the same backing plate 10 (about 4m
m), it is formed as a V-cut groove having a depth and an opening width of about 2 × 2 mm. Accordingly, the soil return plate 10 is strong against an external pressure (for example, muddy water pressure), but relatively weak against an internal pressure (for example, the pressure by the compaction pile 6), and is broken by the compaction pile 6 ( So-called knockout)
Is easy. When the compacted pile 6 is lowered into the guide pipe 4 settled on the tip ground (hole bottom) of the pile hole,
The tip of the compaction pile 6 is protruded into a through-hole 11 located substantially at the center of the soil return plate 10. When the compaction pile 6 is strongly pushed down, the earth return plate 10 is broken in a tulip shape along the cut groove 9, and the compaction pile 6 penetrates into the tip ground and has a desired depth in the tip ground. It is completely penetrated, and compacts the tip ground by its volume effect. At this time, the soil return plate 10 blocks the upward discharging of the soil due to the intrusion of the compaction pile 6 and prevents the intrusion into the guide pipe 4. In particular, clay sheet 1
Even when 0 is broken in the form of a tulip along the radially arranged cut grooves 9, each broken piece adheres to the outer peripheral surface of the compaction pile 6 in a curved state, so that the soil removal is blocked. The blocking action is well performed. (See FIG. 4B)
Examples of the method of penetrating the compaction pile 6 include a method of dropping by free fall, a method of hammering or a static pushing method by a hydraulic jack, and the like. A method of fitting the square axis of the tip of the rotating shaft into the square hole at the upper end of the shaft and rotating the screw with a rotating machine and screwing it into the tip ground can be suitably implemented. The compacted pile 6 that has penetrated sufficiently deep into the tip ground is then firmly fixed by the filling mortar 16 (or cement milk, concrete) filled in the guide pipe 4 (see FIG. 4B). Since the earth return plate 10 prevents intrusion of earth removal, high-quality hollow mortar can be constructed.

[0011]

Second Embodiment FIG. 3 shows a construction drawing of a high-strength cast-in-place concrete pile 2 in which a hole for a pile is excavated in the ground to a depth reaching a support layer, and a reinforcing cage is inserted in the hole for the pile. A guide pipe 4 is installed together with 3. Guide pipe 4
Are arranged at three positions appropriately distributed based on the diameter of the pile hole 2 (approximately 1 to 4 m) and the cross-sectional shape thereof (however, the position and the number are limited to those in the illustrated example). is not). Each guide pipe 4 is integrally attached to the reinforced cage 3 by a method such as bundling or welding to the reinforced cage 3, and the guide pipe 4 is also installed in the pile hole for the installation of the reinforced cage 3. You.

As described with reference to FIGS. 1 and 2, the guide pipe 4 has an inner diameter slightly larger than the outer diameter of the compaction pile 6, has a length at least equal to the depth of the pile hole, and has a tip opening. The part is shielded by the earth return plate 10.

[0013]

Third Embodiment FIGS. 4A and 4B show a ready-made concrete pile 14 used for construction of a high-bearing embedded pile. This is a configuration in which the hollow portion 14a of the ready-made concrete pile 14 is used as a guide pipe of the compacted pile 6, and the compacted pile 6 is provided at the lower end in the hollow portion 14a of the ready-made concrete pile 14.
A short guide pipe 4 'with an inner diameter slightly larger than the outer diameter of
The mounting plate 15 is installed concentrically by welding or the like to the tip fitting 13. The tip 4b of the guide pipe 4 'protrudes from the position of the tip fitting 13 by a dimension h of about 5 to 20 cm. The opening at the tip end of the guide pipe 4 'is shielded by the earth return plate 10 having the configuration described in the first embodiment. The upper end of the guide pipe 4 ′ is an inverted conical guiding section 4.
a. Therefore, the ready-made concrete pile 14
The compacted pile 6 inserted into the hollow portion 14a is always guided into the guide pipe 4 'and positioned at the center of the pile.
After the ready-made concrete pile 14 is built in the excavation hole, the compacted pile 6 penetrates into the tip ground 5 (FIG. 4B). Thereafter, filling the inside mortar 16 (or cement milk, concrete) inside and outside the hollow portion 14a and the guide pipe 4 'and fixing the compaction pile 6 is the same as in the first embodiment.

[0014]

Fourth Embodiment FIG. 5 also shows an embodiment in which the inner diameter of the ready-made pile 5 is several times larger than the outer diameter of the compacted pile 6, which is also used for embedded piles. In the cross section of the large-diameter hollow portion 5a, three (but not limited to) guide pipes 4 'having an inner diameter slightly larger than the outer diameter of the compaction pile 6 are equally arranged and arranged in parallel. Then, it is integrated with the ready-made pile 14 by two upper and lower connecting plates 8a and 8b. The upper end of the guide pipe 4 'is formed as an inverted conical guide 4a for introducing the compaction pile 6, and the upper connecting plate 8a is installed at the same level as the upper end thereof. The distal end 4b of the guide pipe 4 'protrudes from the position of the lower connecting plate 8b by a slight length h. Each guide pipe 4 '
The opening at the front end is also shielded by the earth return plate 10 having the configuration described in the first embodiment. Reference numeral 17 in FIG. 5 denotes a through hole provided in the connecting plate 8a. Through this through hole 17, a filling mortar or the like is filled between the upper and lower connecting plates 8a and 8b.

[0015]

Other Embodiments The cross-sectional shape of the guide pipe is not limited to the circular shape shown in FIG. It can be implemented in exactly the same way with square pipes or hexagonal pipes.

[0016]

According to the guide pipe for a compacted pile according to the present invention, the work for setting up the guide pipe or the ready-made pile can be easily performed with good workability without being disturbed by the muddy water in the hole. In addition, it is possible to prevent the earth discharge generated when the compacted pile 6 penetrates from penetrating into the guide pipes and the ready-made piles, and to contribute to the construction of a high-strength cast-in-place concrete pile having a large tip supporting force and high reliability. It contributes to the construction of structures with excellent quality and reliability.

[Brief description of the drawings]

FIGS. 1A and 1B are cross-sectional views showing the structure of a guide pipe tip.

FIG. 2 is a bottom view of the guide pipe of FIG. 1A.

FIG. 3 is a perspective view showing construction of a high strength cast-in-place concrete pile using a guide pipe attached to a reinforced cage.

FIGS. 4A and 4B are cross-sectional views showing an enlarged structure of a guide pipe below a ready-made pile.

FIG. 5 is a sectional view of a large-diameter ready-made concrete pile.

FIG. 6 is a sectional view showing a conventional guide pipe.

[Explanation of symbols]

 4, 4 'guide pipe 6 compacted pile 14 ready-made pile 14a hollow part 10 soil return plate 11 through hole 9 cut groove

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomio Tsuchiya 2-5-1 Minamisuna, Koto-ku, Tokyo Inside the Technical Research Center, Takenaka Corporation (72) Inventor Yoshihiko Kurita 2-5-1 Minamisuna, Koto-ku, Tokyo No. Takenaka Corporation Technical Research Institute Co., Ltd. (72) Inventor Yuyasu Ikuta 4-1-1, Honcho, Chuo-ku, Osaka City Inside Takenaka Corporation, Osaka Main Store (72) Inventor Takuhei Fukuhara Ginza, Chuo-ku, Tokyo No. 21-1, Takenaka Civil Engineering Co., Ltd. (56) References JP-A-4-209207 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02D 13/04

Claims (6)

(57) [Claims] 1. A guide pipe for guiding a compacted pile penetrating into the bottom of a drilled hole such as a cast-in-place concrete pile from the ground to the bottom of the hole, and having an inner diameter slightly larger than the outer diameter of the compacted pile. , Composed of an iron pipe or the like having a length equal to or greater than the depth of the pile hole, etc., and a soil return plate that shields the opening at the tip of the pipe is installed. A through-hole of approximately the same diameter as the tip diameter is provided, and a plurality of cut grooves are formed radially from the center, and the soil return plate is configured to be broken along the cut groove by compaction pile. A guide pipe for a compacted pile, characterized in that it is made. 2. A short guide pipe having an inner diameter slightly larger than the outer diameter of the compaction pile is joined to a tip fitting of the hollow pile of the ready-made pile in a concentric arrangement with the hollow portion of the ready-made pile. The portion protrudes a little from the tip fitting, and is provided with a soil return plate that covers the distal end opening of the guide pipe. The soil return plate has a central portion approximately the same as the tip diameter of the compaction pile. A through hole having a diameter is provided, and a plurality of cut grooves are formed in a radial arrangement from the center, and the soil return plate is configured to be breakable along the cut groove by a compaction pile. A guide pipe for a compacted pile. 3. The guide pipe for a compacted pile according to claim 1, wherein the cut groove is formed on an outer side surface of the earth return plate. 4. The compacted pile according to claim 1, wherein the required number of the guide pipes is integrally attached to a cast-in-place concrete pile or a reinforcing steel wall of a continuous underground wall in a required arrangement. Guide pipe. 5. A guide pipe for a compaction pile, wherein the upper end of the guide pipe according to claim 2 is enlarged in a funnel shape. 6. A plurality of guides having an inner diameter slightly larger than the outer diameter of the compacted pile at a plurality of positions distributed in a cross section of the hollow part in a hollow part of a ready-made pile having a hollow structure and a large diameter. The pipes are arranged side by side, and are each constrained by a connecting plate to an integral structure with the ready-made pile, and the upper end of each guide pipe has a taper suitable for guiding the compacted pile descending in the hollow part. The guide pipe is formed in a funnel shape. B) The opening at the tip of each of the guide pipes is shielded by a soil return plate. And a plurality of cut grooves are formed radially from the center portion, and the soil return plate is configured to be breakable along the cut grooves by compaction piles. Guide pipe for compacting piles.