JP6632389B2 - How to install an infusion bag - Google Patents

Description

The present invention relates to a method of installing infusion bag which Ru used to inhibit subsidence place pile previously applying a load to the ground of the bottom of the pile hole of place pile.

  Cast-in-place concrete piles are formed by drilling a hole in the ground from the ground surface, arranging reinforcing members such as steel cages in the hole, and then casting concrete to form a concrete structure pile in the ground. It is. For this reason, the diameter and length of the pile can be increased as compared with a driven pile in which a pile manufactured in a factory is driven into the ground, so that the pile is used for construction of a foundation that requires a large supporting force.

  As a simple and inexpensive way to increase the bearing capacity of the ground at the bottom of the pile hole so that the cast-in-place concrete pile does not sink, After the concrete is hardened, the injection material is injected into the injection bag and the injection bag is expanded downward from the tip of the pile to apply a load (preload) to the ground at the tip of the pile and compress the ground in advance. There is known a construction method (hereinafter, referred to as a “tip preload cast-in-place pile construction method”) that suppresses settlement of the pile thereafter (for example, see Patent Document 1).

JP 2001-214438 A

According to the technique of Patent Document 1, a frame to which an infusion bag is fixed is attached to the tip (lower end) of a reinforcing cage built into a pile hole, and when the frame reaches the pile bottom, the frame is separated from the reinforcing cage and the pile bottom is separated. The inflatable bag is deployed on the pile bottom by landing the frame that has been deformed into a shape that covers the pile. If the infusion bag can be installed in a deployed state, the infusion bag can be suitably inflated at the pile bottom.
However, because the structure of the mechanism that separates the frame from the reinforced cage when the frame reaches the pile bottom is complicated, it is complicated to separate the frame from the reinforced cage and install the infusion bag on the pile bottom. There was a problem.

An object of the present invention is to provide a method of installing an injection bag for a cast-in-place pile that can be easily deployed and installed on a pile bottom.

The method of installing the injection bag according to the present application is to dispose the injection bag in a state where the injection bag is disposed in the pile hole together with the reinforcing cage built into the pile hole for the cast-in-place pile, and is installed at the bottom of the pile hole. A method for installing an injection bag for installing an injection bag for a cast- in- place pile at the bottom of a pile hole, in which the material is expanded by being injected to compress and compress the pile tip ground ,
The injection bag has a bag having a size capable of covering a lower end of the reinforcing cage,
A pile bottom frame is provided at the lower end of the reinforcing cage so as to be movable up and down, and the reinforcing cage is mounted in the pile hole in a state where the bag body is attached to the lower end of the reinforcing cage through the pile bottom frame. After the bag body reaches the bottom of the pile hole, the position of the pile bottom frame is switched, so that the position of the reinforcing cage placed in the pile hole is adjusted. It was developed and installed at the bottom of the hole.
Further, in this method of installing an infusion bag, the bag is deployed by the weight of the concrete cast into the pile hole.

If installation method of an infusion bag having such a configuration, the reinforcing bar cage after that built up in Kuiana bag infusion bag through the pile bottom frame in a state attached to the lower tip of the reinforcing bar cage, pile the bag Because it can be deployed and installed at the bottom of the hole, for example, the injection bag can be more easily installed than the conventional technique of separating the frame that has reached the pile bottom from the reinforced cage and installing the injection bag at the pile bottom. Can be unfolded and installed at the bottom of the pile. For example, by deploying the bag with the weight of the concrete poured into the pile hole, the bag of the injection bag can be easily deployed and installed on the pile bottom.
Then, by injecting a predetermined amount of the injection material into the bag body deployed and installed at the bottom of the pile hole, the injection bag can be suitably inflated, and the inflated injection bag presses and compresses the bottom of the pile hole. Thus, a load (preload) can be loaded on the pile tip ground.
In addition, if the position of the reinforcing cage arranged in the pile hole can be appropriately adjusted by using the switching of the arrangement of the pile bottom frame, the cast-in-place concrete pile incorporating the reinforcing cage can be suitably formed. .

Also, preferably,
The bag has a size capable of covering a lower end of the reinforcing bar and partially covering a side surface of the reinforcing bar.
If the bag of the infusion bag has a size capable of covering the lower end of the reinforcing cage and covering a part of the side surface of the reinforcing cage, when the bag is deployed at the bottom of the pile hole, For example, it can be installed so as to cover almost the entire area of the bottom. With such an injection bag, the injection material can be injected and inflated, and the bottom of the pile hole can be satisfactorily pressed and compressed.

  ADVANTAGE OF THE INVENTION According to this invention, the injection bag for cast-in-place piles can be easily expanded and installed in a pile bottom.

It is explanatory drawing (a) (b) (c) (d) regarding a tip preload cast-in-place pile method. It is a perspective view which shows the injection bag for cast-in-place piles of this embodiment. It is sectional drawing of an injection bag, and has shown the injection bag (a) before injecting an injection material, and the injection bag (b) after injecting an injection material. It is explanatory drawing which shows the state (a) which attached the injection bag to the rebar basket, and the state (b) which expanded the bag body of the injection bag by casting concrete. It is explanatory drawing which decomposes | disassembles and shows a reinforced cage, a pile bottom frame, and an injection bag. It is explanatory drawing (a) (b) regarding switching of arrangement | positioning of the pile bottom frame with respect to a reinforcement cage.

  Hereinafter, an embodiment of an infusion bag for a cast-in-place pile and a method of installing the infusion bag according to the present invention will be described in detail with reference to the drawings. However, the embodiments described below are provided with various technically preferable limits for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

First, the tip preload cast-in-place pile method will be described.
In the tip preload cast-in-place pile method, first, as shown in FIG. 1A, a pile hole 1 for a cast-in-place concrete pile is drilled in the ground. This process is referred to as a “pile hole drilling process”.
Drilling of the pile hole 1 is performed while filling the pile hole 1 with water (liquid for drilling) mixed with particles such as bentonite in order to prevent collapse of the pile hole side wall 1a. For this reason, a soft mud-like slime portion 1c in which fine soil particles whose ground has been drilled is settled is formed at the bottom 1b of the pile hole 1, which is the tip (lower end) of the pile.

Further, the reinforcing rod cage 2 is prepared outside the pile hole 1 in advance. The rebar basket 2 is manufactured by assembling a plurality of bar-shaped main rebars arranged in the longitudinal direction and a plurality of hoop rebars (band rebars) arranged in an annular shape with a cylindrical iron wire, for example, and binding them. .
An infusion bag 100 described later is attached to the lower end of the reinforcing bar cage 2, and the injecting bag 100 is hung along with the reinforcing bar cage 2 by a crane 3 or the like, and built into the pile hole 1, as shown in FIG. In this way, the infusion bag 100 is set on the bottom 1b (pile tip ground) of the pile hole 1. This process is referred to as a “rebar basket / injection bag depositing process”.
In addition, a pile bottom frame 21 described later is provided at the lower end of the reinforcing basket 2 so as to be able to protrude and retract, and the infusion bag 100 is attached to the reinforcing basket 2 via the pile bottom frame 21.

  Next, as shown in FIG. 1 (c), the concrete 4 in a fluid state, which has been manufactured in advance in a concrete plant, is poured into the pile hole 1 using a concrete pump 4a and a concrete pumping pipe 4b, and is poured. By hardening the cast concrete 4, a cast-in-place concrete pile is formed in the ground. This process is called a “concrete casting process”.

Next, as shown in FIG. 1D, the injection pump 41 is connected to the injection hose 40, the discharger 51 is connected to the discharge hose 50, and the injection material G is sent to the injection bag 100. At this time, the injection valve B1 and the discharge valve B2 are open.
When the injection material G reaches the discharger 51 side and it is confirmed that the air bubbles in the injection bag 100 have been removed, the discharge valve B2 is closed, and the liquid supply by the injection pump 41 is continued. Inject.
Then, a predetermined amount of the injection material G is injected to inflate the injection bag 100, and after confirming that a predetermined pressure has been applied to the injection bag 100 for a predetermined time, the injection valve B1 is closed and the injection pump 41 is stopped.
In this way, the injection material G is injected into the injection bag 100, and the injection bag 100 is inflated. The inflated injection bag 100 pressurizes and compresses the bottom 1b of the pile hole 1, and a load (preload) is loaded on the pile tip ground. This step is called a “preloading step”. This preload increases the bearing capacity of the pile tip ground and reduces pile settlement.

Next, the injection bag 100 for the cast-in-place pile of the present embodiment will be described.
As shown in FIGS. 2, 3A and 3B, the injection bag 100 includes a water-impermeable bag 10, an injection hose 40 and a discharge hose 50 connected to the bag 10, and the like. I have.
A plurality of (six in the present embodiment) band mounting portions 10d are provided on the outer edge of the bag body 10.

The injection hose 40 and the discharge hose 50 are flow paths for the injection material G. The injection hose 40 is a flow path for feeding the injection material G from the injection pump 41 into the bag body 10. And a flow path for sending the injection material G from the discharge device 51 to the discharger 51.
The injection hose 40 and the discharge hose 50, for example, penetrate the bag body 10 and are connected to both ends of a perforated pipe (not shown) housed in the bag body 10, respectively. The perforated pipe (not shown) is formed by forming a large number of holes on the peripheral surface of a tubular member made of, for example, a resin material or a metal material. It serves as a flow channel, through which the injection material G flows into the bag 10.
Then, in a state in which the discharge valve B2 is closed and the injection material G does not flow into the discharge hose 50, the injection material G pressurized flows into the bag body 10 from the hole of the perforated pipe (not shown), and the bag body 10 ( The infusion bag 100) is inflated (see FIG. 3B).

The bag body 10 is a member formed by laminating a sheet material having water impermeability (water stoppage), pressure resistance and flexibility.
The bag body 10 is formed in a bag shape like a floating ring by laminating an outer peripheral edge and an inner peripheral edge of a circular upper sheet material and a lower sheet material each having a round hole in the center.
A mesh sheet 10c for draining is attached to the central round hole (inner peripheral edge), and a plurality of band attachment portions 10d are attached to the outer edge (outer peripheral edge). The band mounting portion 10d is a tongue-shaped member formed using the same material as the sheet material of the bag body 10, and has an opening for attaching the elastic band 60. The mesh sheet 10c is a well-known member provided for preventing mud (slime 1c) at the bottom 1b of the pile hole 1.
The bonding of the sheet materials can be performed by bonding with an adhesive, pressure bonding by pressure, welding by heating, or a bonding method in which these are combined. In addition, a through-hole through which the injection hose 40 and the discharge hose 50 pass is formed in the upper sheet material, and the edge of the through-hole is attached to the peripheral surface of the injection hose 40 and the discharge hose 50, respectively. I have.
As the material of the sheet material forming the bag body 10, for example, a synthetic resin material such as a thermoplastic resin and a thermosetting resin, specifically, polyethylene, polyvinyl chloride, vinylidene chloride, polypropylene, polyamide, or the like may be used. it can. Further, rubber-based materials (including synthetic rubber and elastomer-based materials in addition to natural rubber) can also be used.

Then, as shown in FIGS. 3A and 3B, by injecting the injection material G into the bag body 10, the bag body 10 (the injection bag 100) can be inflated.
In this way, a predetermined amount of the injection material G is injected into the bag body 10 to inflate the injection bag 100, whereby the expanded injection bag 100 presses and compresses the bottom 1 b of the pile hole 1 to apply a load (preload) to the pile tip ground. ) Can be loaded.

As the injectable material G, a material that is hardened after being injected into the bag body 10 in a flowable state can be used.
In this embodiment, cement milk is used as the injection material G. A grout material other than cement milk, a curable resin material, or the like can also be used as the filling material G.

The elastic band 60 is a band-like or cord-like elastic member made of, for example, natural rubber or synthetic rubber, and has one end connected to the band mounting portion 10d of the bag 10, and a connecting member 70 provided at the other end. Have been. Note that a spring member such as a coil spring can be used as the elastic band 60.
The connecting member 70 is, for example, a hook, and can be attached to an arbitrary portion of the reinforcing bar cage 2.

Then, as shown in FIG. 4 (a), the connecting member 70 was attached to a predetermined position of the reinforcing cage 2, and the infusion bag 100 was attached to the reinforcing cage 2 so as to cover the lower end of the reinforcing cage 2 with the bag 10. In this state, the rebar basket 2 is erected in the pile hole 1, and the infusion bag 100 is installed at the bottom 1 b of the pile hole 1.
In particular, since the infusion bag 100 of the present embodiment is attached to the lower end of the reinforced cage 2 using the extendable telescopic band 60, the infusion bag 100 is disposed together with the reinforced cage 2 in the pile hole 1. As shown in FIG. 4B, if concrete 4 is poured into the pile hole 1, the elastic band 60 of the injection bag 100 is extended by the weight of the concrete 4, and the bag body 10 is moved to the bottom 1 b of the pile hole 1. It can be deployed and installed.
Further, as shown in FIG. 4A, the bag body 10 of the infusion bag 100 has a size capable of covering the lower end of the reinforcing basket 2 and covering a part of the side surface of the reinforcing basket 2. Therefore, when the bag body 10 is deployed at the bottom 1b of the pile hole 1, it can be installed so as to cover the entire bottom 1b.
4A and 4B, illustration of the injection hose 40 and the discharge hose 50 is omitted.

As shown in FIGS. 4, 5 and 6, a pile bottom frame 21 is provided at a lower end of the reinforcing bar cage 2 of the present embodiment so as to be movable up and down. And is attached to the reinforcing bar cage 2 through the wire.
Here, the pile bottom frame 21 provided in the reinforcing bar 2 will be described.

As shown in FIG. 5, the pile bottom frame 21 has a frame main body 21 a disposed at a position facing the bottom 1 b of the pile hole 1, and the frame main body 21 a can be slid up and down at the lower end of the reinforcing cage 2. And a frame holding portion 21b for holding.
The frame holding portion 21b includes a frame portion 2a fixed to the lower end of the reinforcing rod cage 2, a plurality of (six in the present embodiment) slide bars 2b which are vertically movably inserted through the frame portion 2a, and the slide bars. The slide bar 2b is provided with a retaining member 2c and the like fixed to an upper portion of the slide bar 2b, and a frame body 21a is fixed to a lower portion of the slide bar 2b.

When the reinforced basket 2 provided with the pile bottom frame 21 is suspended by a crane or the like, the frame main body 21a projects below the reinforced basket 2 as shown in FIG. . At this time, the retaining member 2c fixed on the upper portion of the slide bar 2b abuts on the upper surface of the frame portion 2a, and regulates the movement so that the frame main body 21a does not protrude any more.
When the frame main body 21a comes into contact with the bottom 1b of the pile hole 1 by, for example, embedding the reinforcing rod cage 2 into the pile hole 1, the frame main body 21a moves relatively upward as shown in FIG. The slide bar 2b comes out above the frame portion 2a and retracts toward the reinforcing bar cage 2 so that the frame main body 21a moves in a direction approaching the reinforcing bar cage 2.
As described above, since the frame main body 21a is provided so as to be movable up and down with respect to the reinforcing rod cage 2, after the bag 10 of the reinforcing rod cage 2 built in the pile hole 1 reaches the bottom 1b of the pile hole 1. By switching the arrangement of the frame body 21 a of the pile bottom frame 21, the position of the reinforcing cage 2 disposed in the pile hole 1 can be adjusted. This makes it possible to suitably form the cast-in-place concrete pile.

  Next, a method of installing the infusion bag for installing the infusion bag 100 for the cast-in-place pile of the present embodiment at the bottom 1b of the pile hole 1 will be described.

First, as shown in FIG. 4A, the connecting member 70 is attached to a predetermined location of the reinforcing bar cage 2, and the infusion bag 100 is mounted on the reinforcing bar cage 2 so that the bag 10 covers the lower end of the reinforcing bar cage 2.
Then, the reinforcing rod cage 2 to which the infusion bag 100 is attached is built into the pile hole 1 as shown in FIG.
In addition, after the bag body 10 at the lower end of the reinforcing cage 2 built in the pile hole 1 reaches the pile bottom (bottom 1b), utilizing the fact that the frame body 21a of the pile bottom frame 21 moves up and down, Adjust the position of the reinforcing rod cage 2 disposed in the pile hole 1.

Next, as shown in FIG. 1 (c), concrete 4 is poured into the pile hole 1.
At this time, as shown in FIG. 4 (b), the elastic band 60 of the injection bag 100 extends due to the weight of the concrete 4 cast in the pile hole 1, and the bag 10 covering the lower end of the reinforcing cage 2. Unfolds so that the outer edge of the
In other words, after the rebar basket 2 is installed in the pile hole 1 with the bag body 10 of the infusion bag 100 attached to the lower end of the rebar cage 2, the concrete 4 is poured into the pile hole 1, and The body 10 can be deployed and installed on the bottom 1b of the pile hole 1.
Then, after the cast concrete 4 is hardened to form a cast-in-place concrete pile in the ground, a predetermined amount of the injection material G is injected into the bag body 10 to inflate the injection bag 100. The bottom 1b of the pile hole 1 is pressurized and compressed by the injection bag 100 inflated in this way, and a load (preload) is loaded on the pile tip ground.

As described above, the infusion bag 100 of the present embodiment is configured to be attached to the lower end of the reinforced basket 2 using the extendable elastic band 60, and the reinforced basket 2 to which the infused bag 100 is attached is connected to the pile hole 1. Then, the concrete body 4 is poured into the pile hole 1 so that the bag body 10 can be deployed and installed at the bottom 1 b of the pile hole 1.
In other words, if the injection bag 100 for a cast-in-place pile used by being attached to the lower end of the reinforcing cage 2 using the extendable elastic band 60, the frame reaching the pile bottom as in the related art is removed from the reinforcing cage. The infusion bag 100 (bag body 10) can be deployed and installed on the pile bottom 1b more easily than the method of separating and placing the infusion bag on the pile bottom.
Then, by injecting a predetermined amount of the injection material G into the bag body 10 deployed and installed on the bottom portion 1b of the pile hole 1, the injection bag 100 can be suitably inflated. By compressing and compressing the bottom 1b, a load (preload) can be loaded on the pile tip ground.

As described above, the injection bag 100 of the present embodiment can be appropriately inflated by the injection of the injection material G, and can apply a predetermined load to the ground.
That is, if the infusion bag 100 is used for the tip preload cast-in-place pile method, it is possible to prevent the settlement from occurring in the cast-in-place concrete pile.

  The application of the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Pile hole 1a Pile hole side wall 1b Bottom 1c Slime part 2 Reinforcing cage 21 Pile bottom frame 3 Crane 4 Concrete 4a Concrete pump 4b Concrete pumping pipe 100 Injection bag 10 Bag body 10c Mesh sheet 10d Band mounting part 40 Injection hose 41 Injection pump 50 Discharge hose 51 Discharge machine 60 Telescopic band 70 Connecting member G Injection material B1 Injection valve B2 Discharge valve

Claims (3)

The pile is arranged in the pile hole together with the reinforcing cage built in the pile hole for the cast-in-place pile, and is installed at the bottom of the pile hole, and is expanded by being injected with the injectable material into the pile, thereby expanding the pile. An injection bag installation method for installing an injection bag for a cast- in- place pile that pressurizes and compresses the tip ground at the bottom of a pile hole,
The injection bag has a bag having a size capable of covering a lower end of the reinforcing cage,
A pile bottom frame is provided at the lower end of the reinforcing cage so as to be movable up and down, and the reinforcing cage is mounted in the pile hole in a state where the bag body is attached to the lower end of the reinforcing cage through the pile bottom frame. After the bag body reaches the bottom of the pile hole, the position of the pile bottom frame is switched, so that the position of the reinforcing cage placed in the pile hole is adjusted. A method for installing an infusion bag, wherein the method is deployed and installed at the bottom of a hole.   2. The method according to claim 1, wherein the bag is developed by the weight of the concrete poured into the pile hole.   The infusion bag according to claim 1, wherein the bag has a size capable of covering a lower end of the reinforcing bar and partially covering a side surface of the reinforcing bar. 4. Installation method.

Images