JP3045481B2 - Construction method of cast-in-place concrete pile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a cast-in-place concrete pile which is one of pile foundation works.

[0002]

2. Description of the Related Art As is well known, cast-in-place concrete piles are prepared by placing piles manufactured in advance in a factory or the like in the ground and placing them in a hole where the ground has been excavated by a machine or human power with respect to a pre-made pile. This is an on-site construction pile in which a reinforcing bar is inserted and concrete is poured into the hole to build it. By the way, as described above, in a site near an aquifer such as a sand layer and a gravel layer, for example, as shown in FIG. 5, in a ground where impermeable layers A and C are formed vertically above and below an aquifer B. When constructing a cast-in-place concrete pile, in order to protect the hole wall of the pile hole 30 for placing concrete, the casing 1 is erected and then the pile hole 30 is excavated.
They built 0, 40, ..., and poured concrete to build piles. Further, piles were formed by pouring concrete into the excavated hole 30 while pouring a bentonite aqueous solution or fresh water to protect the hole wall.

[0003]

However, in the conventional method of constructing a cast-in-place concrete pile at a site near the aquifer B such as a sand layer or a gravel layer as described above,
When a pile is formed using the casing 1, the following problems occur after the casting of the concrete is completed and the casing 1 used for protecting the hole wall 30a is pulled out. In other words, if the concrete has been cast and the initial hardening has not been completed, if the casing is pulled out, the concrete component poured into the aquifer B leaks out and the water content in the aquifer B is reduced. Not only pollutes the soil, but also does not completely ensure the quality of the cast concrete used as the pile foundation.
Further, in the same site as described above, if the bentonite aqueous solution is used to protect the pore wall, soil contamination may be seen when the bentonite aqueous solution enters the ground.

An object of the present invention is to provide a method of constructing a cast-in-place concrete pile which ensures the quality of the poured concrete without leaking the poured concrete into the ground.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a method of constructing a cast-in-place concrete pile according to the present invention is to excavate the ground to form a pile hole for a pile, and A method for constructing a cast-in-place concrete pile in which a concrete pile is formed by casting concrete after the reinforcing cage has been built in, wherein a waterproof sheet is wound in advance on at least a part of the outer periphery of the reinforcing cage through a spacer . Dressed and said
Spacer is used when concrete is cast
Outside the reinforced cage, so as to ensure the thickness of
A plurality of which are arranged on the outer circumference in a state protruding from the circumference
And it is characterized in that pouring the concrete in built up a reinforcing bar cage made by winding the outer periphery of the waterproof sheet via a spacer to the pile hole.

When excavating the ground to form a pile hole, the excavation hole wall of the pile hole is formed in order to prevent collapse of the hole wall.
It is protected by embedding a casing. Then, the casing is pulled out after placing concrete in the excavated pile hole. The method used for drilling the hole pile, the type of excavating machine, the method of earth removal, etc. are various types of cast-in-place pile method such as all casing (Venoto) method, earth drill method, reverse circulation method and the like. It may be performed by any method of the corresponding excavation method.

[0007] The waterproof sheet may be made of any material such as vinyl as long as it is impermeable to water. For example, a rubber sheet is suitable. The waterproof sheet may be attached in any manner as long as the outer periphery of the reinforcing rod cage is wound around via a spacer . For example, a configuration is possible in which the rebar basket is wound with a waterproof sheet having a predetermined length and width, and the lower and upper ends of the waterproof sheet are bound to the rebar basket by a number line.

In the case where the waterproof sheet is a rubber sheet, when the concrete is poured, the rubber sheet extends toward the hole wall due to the internal pressure of the poured concrete. Use as little as possible. Since the rubber sheet extends toward the hole wall in this manner, the quality of the concrete pile to be formed is improved, and the foundation becomes a foundation having more stable supporting force.

[0009] The waterproof sheet pre-wound on the outer periphery of the reinforced basket may be wrapped around the outer periphery of the reinforced basket, such as the entire outer periphery of the reinforced basket or a part thereof. The location is optional. For example, when the ground to be formed by excavation to form a pile hole is a ground having an impermeable layer above and below an aquifer, the waterproof sheet is used for the aquifer when a reinforced cage is built in the ground. It is preferable to wind the reinforcing bar so as to be arranged at a position corresponding to the layer portion. This means that the waterproof sheet is wound around the rebar basket so as to cover the upper and lower impermeable layers. In addition, the concrete is usually put into the pile hole from below the excavated pile hole by inserting a tremy tube into the pile hole.

According to the first aspect of the present invention, a waterproof sheet is previously placed on the outer periphery of a pile hole for a pile formed by excavating the ground .
After that built up the rebar cage that wound through the pacer, because to Da設the concrete to construct a concrete pile, said
Even if the concrete is cast into the pile hole in which the reinforcing rod cage in which the waterproof sheet is wound in advance through a spacer is inserted, the inside and the outside of the reinforcing rod basket in the portion where the waterproof sheet is wound on the outer periphery. And concrete inside is blocked by the tarpaulin,
It does not leak into the outside ground.

[0011] Therefore, when the casing that protects the hole wall of the pile hole is pulled out after the concrete has been cast, even if the initial hardening of the cast concrete has not been completed, the inside of the rebar cage is not required. The concrete component does not leak into the ground from the ground, preventing soil contamination, protecting uncured concrete, and ensuring the quality of the cast concrete pile.

[0012] In particular, in the case of constructing a pile foundation with a cast-in-place concrete pile on the ground having an aquifer, the concrete was poured into a pile hole in which a steel cage was built, and the concrete was used to protect the hole wall. Even after the casing has been pulled out, even if the initial hardening of the cast concrete has not been completed, the concrete component cast into the ground leaks out of the steel cage and is contained in the ground (especially aquifer). Since the concrete component does not mix with the water, the leaked concrete component does not contaminate the soil, and the quality of the cast concrete used as the pile foundation is completely ensured. Also before
The spacer is used for concrete when casting concrete.
Of the reinforcing steel cage to be built
There are multiple pieces arranged on the outer circumference so that they protrude from the outer circumference
The thickness of the concrete when casting concrete
Can be assured. Claim 2 of the present invention
The construction method of the concrete pile is the cast-in-place method according to claim 1.
In the method for constructing a concrete pile, the waterproof sheet
Is a rubber sheet, and the upper end of the waterproof sheet is
It is suspended from the part corresponding to the head with a track,
The lower end of the tarpaulin is the lower end of the tarpaulin.
It is characterized in that it is bound to the spacer located at
You. According to the invention described in claim 2, the rebar basket and the rubber cage
The binding portion of the waterproof sheet is configured as small as possible.
The reinforced basket with this rubber tarpaulin
When concrete is cast after the concrete
The waterproof sheet extended to the hole wall side by the internal pressure of
Concrete will be filled further in the pile hole.
The quality of the concrete pile to be created.
It becomes a concrete pile foundation with stable bearing capacity.
Further, the reinforcing rod cage 2 having the waterproof sheet is connected to the pile hole.
When it is inserted into the
The lower end of the water sheet will not roll up. Book
Construction method of cast-in-place concrete pile according to claim 3 of the invention
Is the cast-in-place concrete pile according to claim 1 or 2.
In the construction method, of the plurality of spacers,
In a row extending in the extending direction of the main muscle, the extending direction of the main muscle is
Attach an L-shaped guide angle that extends to the front
One end of the waterproof sheet, one side of the guide angle
Glue at one surface and glue the other end around the reinforced cage
Over the one end of the waterproof sheet
It is characterized by bonding. The invention according to claim 3
According to one embodiment, one end of the waterproof sheet is attached to the guide ang.
Glued on the surface which is one side of the
Weight is applied on one end of the waterproof sheet to which the end is adhered.
Glued so that the waterproof sheet is
Is wound.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for constructing a cast-in-place concrete pile according to the present invention will be described below in detail with reference to FIGS. Here, a case will be described in which a cast-in-place concrete pile is driven into a stratum including an aquifer.

FIG. 1 to FIG. 4 are views showing one embodiment of a method for constructing a cast-in-place concrete pile to which the present invention is applied.

First, the configuration will be described. 1 is a casing,
2 is a steel cage, 3 is a rubber sheet as a waterproof sheet, 20,
Reference numeral 21 denotes a main reinforcing bar and a stirrup of the rebar cage 2, 22 denotes a spacer, 23 denotes a guide angle, 30 denotes a pile hole for a pile,
Reference numeral 0a denotes a hole wall of the pile hole 30.

FIG. 1 is a longitudinal sectional view for explaining an embodiment of the method for constructing a cast-in-place concrete pile according to the present invention.
The ground on which the cast-in-place pile in this figure is constructed includes strata A and C, which are impermeable layers, and aquifer B, which is a stratum sandwiched between the impermeable layers A and C. FIG. 2 is a plan view of the reinforced cage shown in FIG. 1 used in the embodiment of the method for constructing a cast-in-place concrete pile of the present invention, FIG. 3 is an enlarged view of a portion X in FIG. 2, and FIG. 3 is a sectional view taken along line DD of FIG.

As shown in FIG. 1, a pile hole 30 formed by excavating the ground in the vertical direction is formed in the ground, and the waterproof sheet 3 is previously formed on the outer periphery of the pile hole 30. A reinforced steel cage 2 wound around is built. The pile hole 3
The 0-hole wall 30a is protected by the casing 1 built on the ground so as not to collapse during excavation.

The casing 1 is built over the water-impermeable layers A to C, and the water-impermeable layers A and C
The water contained in the aquifer B sandwiched between the holes is prevented from entering the inside of the pile hole 30 to facilitate the work of placing the concrete pile.

Although not shown, this pile hole 30 is not shown.
Is excavated downward to a predetermined depth,
The reinforced cage 2 built in the pile hole 30 is such that the tip of the reinforced cage 2 reaches a predetermined excavated depth.
It is, of course, built.

The reinforced cage 2 is arranged in the pile hole 30 direction (vertical direction).
, 21 are arranged at predetermined intervals at the main bars 20, 20,.
It is attached (not shown) by bundling or welding in the direction (lateral direction) orthogonal to 0,..., 20 and formed into a substantially cage-like shape, and spacers 22, 22, 2,
2, 22 are provided in plurality. These spacers 22, 22, 22,... Are used to secure the covering thickness of the concrete when the concrete is cast, and are provided so as to protrude from the outer periphery of the reinforcing steel cage to be built. And any shape may be used as long as the shape exerts the action as described above.

In this embodiment, the plurality of spacers 22, 22,... Are arranged at four locations on the outer periphery at equal intervals, and the spacers 2 provided at the four locations are provided.
From 2,22,22,22, they are located at predetermined intervals so as to form a row on the outer periphery in the vertical direction (extending direction of the main bar 20). As described above, the spacers 22, which are arranged in four rows at predetermined intervals in the extending direction of the main bars 20, 20,.
One row of 22, 22, 22 (X part shown in FIG. 2)
An L-shaped guide angle 23 is attached in the longitudinal direction by welding.

As shown in FIG. 4, one end 22a of the guide angle 23 is welded to the main reinforcement 20a which is one of the main reinforcements 20 constituting the rebar cage 2,
The other ends 22b of the spacers 22, 22, 22 are provided such that the other ends 22b protrude outward from between the strips 21, 21 provided orthogonal to the main bars 20a. In the above, both surfaces are connected in a state of contact with each other. Here, the spacers 22, 22, 22, 22
Are welded to the main bars 20, 20a. However, the present invention is not limited to this, and they may be attached by welding to the band bars 21, 21,... At predetermined positions. Further, the spacer 22 is attached to the reinforcing bar 2 by welding, but is not limited to this as long as it is to be fixed, and may be attached by bundling, bolts, or the like. As shown in FIGS. 2 to 4, the waterproof sheet 3 is wound around the outer periphery of the pile head of the reinforced cage 2 via the guide angle 23.

In this embodiment, a rubber sheet is used as the waterproof sheet 3. As shown in FIG. 3, the waterproof sheet 3 has a surface portion 23 a forming an L-shape of the guide angle 23. One end 31 of the waterproof sheet 3 in the main reinforcement direction is adhered, and the waterproof sheet 3 is wound so as to cover the outer periphery of the reinforcing bar cage 2. Are glued together.

The upper end 3a of the wrapped waterproof sheet 3 is located above the main reinforcement, that is, the main reinforcement 20, 20, which corresponds to the pile head, so that the waterproof sheet 3 does not slip down. .., And the lower end 3 b of the waterproof sheet 3 is provided at four locations located at the lower end 3 b of the waterproof sheet 3.
No. 2, 22, 22 are bound. (Not shown)
This is to prevent the lower end portion 3b of the waterproof sheet 3 from rolling up due to friction or the like when the reinforced cage 2 having the waterproof sheet 3 is inserted into the pile hole 30 due to friction at the time of insertion. is there.

That is, the waterproof sheet 3 and the reinforcing bar 2 in this embodiment are connected to an upper end 3a suspended by a wire and a lower end 3 bound to the wire.
b and the bonding portion 23a with the guide angle 23.

As described above, the binding portion between the rebar basket 2 and the waterproof sheet 3 is made as small as possible. In this embodiment, the waterproof sheet 3 is a rubber sheet. When the concrete is cast after the reinforced basket 2 having the concrete 3 is built, the rubber waterproof sheet 3 is formed by the internal pressure of the concrete that has been cast.
This is because it extends to the side and leads to the improvement of the quality of the concrete pile to be formed, and becomes a concrete pile foundation having more stable bearing capacity.

Next, the reinforced cage 2 having the waterproof sheet 3
Will be described.

First, a plurality of main bars 20, 2 as described above are used.
., And the reinforcing bars 21, 21, 21,...
The spacers 22, 22,...
At the lower end 3b of the portion where the waterproof sheet 3 is wound later, the spacers 22 and 2 are attached.
Attach 2,22,22. In this way, the reinforced cage 2
Spacers 22, 2 attached at equal intervals to the outer periphery of
A guide angle 23 having an L-shaped cross section extending in the direction in which the main bar 20 extends is attached to one of the rows 2, 22, 22 extending in the direction in which the main bar 20 extends by welding. The waterproof sheet 3 is wound around the outer periphery of the reinforced cage 2 at the location where the is provided (part of the reinforced cage 2 corresponding to the pile head).

Next, one end 3 of the wound waterproof sheet 3
1 as shown in FIG.
Adhesion is performed at the surface portion 23a which is one surface forming the mold, and the other end portion 32 around which the reinforcing rod cage 2 is wound is adhered so as to overlap the one end portion 31 of the waterproof sheet 3 to which the adhesion is applied.

The upper end 3a of the wrapped waterproof sheet 3 is suspended from the upper part of the main bar 20 by a number line so that the waterproof sheet 3 does not slide down. The spacer 3 is located at the lower end 3 b of the waterproof sheet 3.
22 is assembled by binding with a line.

Next, a method for constructing a cast-in-place concrete pile according to an embodiment of the present invention using the reinforced cage 2 having the waterproof sheet 3 as described above will be described.

First, the ground having the aquifer B is preliminarily dug by a drilling machine such as an earth drill.
In order to protect the collapse of the excavated hole wall 30a, the casing 1 is erected vertically, and then the pile holes 30 for the piles are formed. The method of excavating the pile hole 30 for the pile may be any method. Then, the reinforced cage 2 having the waterproof sheet 3 formed as described above is lifted and built into the excavated pile hole 30 by a machine having a crane function such as the earth drill machine. At this time, the reinforced cage 2
The erection is performed while paying attention to the verticality of the reinforcing bar 2 to be erected. The waterproof sheet 3 is
It is wound at an arbitrary position in the reinforced cage 2 and is provided here on the outer periphery of the reinforced cage 2 at a position corresponding to the pile head. When the reinforced cage 2 is erected in this manner, the reinforced cage 2 is wound around the outer periphery of the laid waterproof sheet 2 at a position corresponding to the aquifer B in the inner space of the casing 1. The pile head is ready to be placed.

Then, a tremy tube is inserted into the pile hole 30 in which the reinforcing cage 2 is built, and the pile hole 3 is inserted.
Concrete is poured from below 0. When concrete is cast in this manner, the rubber waterproof sheet 3 wound around the outer periphery of the reinforced cage 2 extends toward the hole wall 30a due to the internal pressure of the cast concrete. Due to the extension of the waterproof sheet 3 toward the hole wall, the concrete is further filled in the excavated pile hole 30, the quality of the concrete pile to be formed is improved, and the concrete pile foundation having more stable supporting force is provided. Becomes After the above-described concrete placement is completed, the casing 1 used for protecting the hole wall 30a is pulled out from the pile hole 30 to form a cast-in-place concrete pile.

According to the embodiment of the method for constructing a cast-in-place concrete pile according to the present invention, the pile sheet 30 formed by excavating the ground has a waterproof sheet 3
After the reinforcement basket 2 is wound, concrete is cast and a concrete pile is formed. Therefore, the concrete is placed in the pile hole 30 in which the reinforcement basket 2 on which the waterproof sheet 3 is wound in advance is built. Even if it is cast, the inside of the reinforced basket 2 is separated from the outside at the portion where the waterproof sheet 3 is wound around the outer periphery, and the concrete inside is blocked by the waterproof sheet 3 and the outside is Does not leak into certain grounds.

Therefore, when constructing a pile foundation with a cast-in-place concrete pile on the ground having the aquifer B, after the concrete is poured into the pile hole 30 in which the reinforced cage 2 is built, the hole wall 30a is removed. After the protective casing 1 is pulled out, even if the initial hardening of the cast concrete has not been completed, the concrete component does not leak into the ground from the inside of the reinforced cage 2 and is poured into the ground. Concrete component leaked to the outside of the reinforced cage 2,
In particular, it does not mix with the water contained in the aquifer B.
As a result, the soil is not contaminated by the leaking concrete component, the uncured concrete is protected, and the quality of the cast concrete pile serving as a pile foundation can be reliably ensured.

In the present embodiment, the waterproof sheet 3 previously wound on the outer periphery of the reinforcing cage 2 is wound on the pile head, but is not limited thereto. The outer periphery of the reinforcing bar 2 may be wound in any manner, such as the entire outer periphery or another part thereof, and the winding location is arbitrary. In addition, it is needless to say that specific detailed structures and the like can be appropriately changed.

[0037]

As described above, according to the method for constructing a cast-in-place concrete pile according to the first aspect of the present invention, a reinforcing steel basket having the waterproof sheet wound around the outer periphery is built into the pile hole, and the concrete is piled up. After casting, when the casing that protects the hole wall of the pile hole is pulled out, even if the initial hardening of the cast concrete has not been completed, the concrete component enters the ground from the inside of the reinforced cage. Leakage can be prevented, soil contamination can be prevented, and uncured concrete can be protected to ensure the quality of the cast concrete pile. Further, the spacer is made of concrete.
To ensure the concrete covering thickness when placing
At the outer periphery of the reinforcing bar cage
When concrete is cast,
It is possible to ensure the concrete covering thickness. Contract
According to the invention as set forth in claim 2, the rebar basket and the rubber cage
The binding part of the tarpaulin is made as small as possible.
After building a reinforced cage with rubber tarpaulin
When concrete is cast, the concrete
The waterproof sheet extends to the hole wall side by pressure, and the excavated pile hole
The concrete will be further filled in
Improve the quality of the concrete pile to be formed and make it more stable
It becomes the concrete pile foundation with the improved bearing capacity. Also,
Insert the reinforcing bar cage 2 having the waterproof sheet into the pile hole
When the waterproof seal is inserted,
So that the lower end of the gate does not roll up. Claim 3
According to the described invention, one end of the waterproof sheet is
Adhere at the surface that is one side of the guide angle,
One end of the waterproof sheet with the other end wound with a basket adhered
Glued on top of each other, with the front
The waterproof sheet is wound.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view for explaining one embodiment of a method for constructing a cast-in-place concrete pile of the present invention.

FIG. 2 is a plan view of the reinforced cage of FIG. 1 used in one embodiment of the method for constructing a cast-in-place concrete pile according to the present invention.

FIG. 3 is an enlarged view of a portion X in FIG. 2;

FIG. 4 is a sectional view taken along line DD of FIG. 3;

FIG. 5 is a longitudinal sectional view illustrating a conventional method of constructing a cast-in-place concrete pile on the ground where the aquifer B is formed.

[Description of Signs] 1 casing 2 reinforced cage 3 waterproof sheet 30 pile hole 30a hole wall

Continuation of front page (72) Inventor Hiroshi Kashino 1-6-11-202 Midori, Sumida-ku, Tokyo Yukenai Co., Ltd. (56) References JP-A-63-60319 (JP, A) 35326 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) E02D 5/34-5/44

Claims (3)

(57) [Claims] 1. A method of constructing a cast-in-place concrete pile, in which a ground hole is formed by excavating the ground to form a pile hole for a pile, a reinforcing cage is built in the pile hole, and then concrete is poured to form a concrete pile. A waterproof sheet is previously applied to at least a part of the outer periphery of the reinforcing rod cage.
It is wound around via a spacer , and the spacer is used as a component when concrete is cast.
Iron to be built in, so as to secure the thickness of the cleat
A plurality of braces are arranged on the outer periphery in a state protruding from the outer periphery.
Shall and then, the construction method of in-place concrete piles characterized by pouring the concrete in built up a reinforcing bar cage made by winding the outer periphery of the waterproof sheet via a spacer to the pile hole. 2. The cast-in-place concrete pile according to claim 1,
In the construction method, the waterproof sheet is a rubber sheet, and the waterproof sheet
Is suspended from the part corresponding to the pile head with a track.
The lower end of the waterproof sheet is
Bundling to the spacer located at the lower end of the sheet
Construction method of cast-in-place concrete pile characterized by the following. 3. A cast-in-place concrete according to claim 1 or 2.
In the method for constructing a port pile, the plurality of spacers extend in a direction in which main bars of the reinforcing bar extend.
L-shaped cross section extending in the extending direction of the main bar in a row
Attach one end of the waterproof sheet to one side of the guide angle
And the other end wound with the reinforcing cage is connected.
Put on top of one end of the waterproof sheet
Of cast-in-place concrete piles characterized by being glued to
Construction method.