JP2001032271A - Work execution method of cast-in-place concrete pile having long steel frame therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work execution method of a cast-in-place concrete pile having a long steel frame therein which prevents the slime from settling down on a hole bottom after the second any slime treatment before placing concrete, and sufficiently ensures the pile tip supporting performance and the soundness. SOLUTION: A pile hole 10 is excavated, a pipe 11 for simple treatment is installed in the pile hole 10 after the primary slime treatment at the position of the outer circumference of a cage 5, and the secondary slime treatment is implemented after the cage 5 is built in. The tertiary slime treatment in which the slime is set afloat in a stabilizing solution is started through the pipe 11 for the slime treatment, a long steel frame 7 of the length reaching a hole bottom is built in a center part of the pile hole 10 while the tertiary slime treatment is continued. After the concrete placement is started from the hole bottom by a tremie pipe 6 or the like, the tertiary slime treatment is rapidly completed, and the pipe 11 for the slime treatment is recovered above the ground to complete the concrete placement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the field of construction technology for constructing, for example, steel columns and other steel reinforced concrete piles (hereinafter, may be abbreviated as SRC piles). The present invention relates to a method for constructing an SRC cast-in-place concrete pile that prevents sinking to the bottom to secure tip support performance and prevents deterioration of concrete quality due to slime mixed into concrete.

[0002]

2. Description of the Related Art Conventionally, in the construction of cast-in-place concrete piles, pile holes are drilled by an earth drill method using a stabilizing solution. However, it is well known that excavation dust and slime settle at the bottom of the hole. is there. If slime remains at the bottom of the hole when casting concrete, the tip support performance of the pile will be impaired, and slime will mix into the concrete and reduce its quality. The following slime treatment is generally performed. However, the slime treatment has not been effective as intended.

[0003] Concretely, in the case of constructing a straight pillar for a reverse hitting method by a conventional general earth drilling method, the method of constructing a cast-in-place concrete pile illustrated in Figs.

FIG. 6A shows a stage of pre-drilling by the earth drill 1, and FIG. 6B shows a stage where the casing 2 is erected and the stabilizer 3 is injected. C indicates the stage of excavation of the shaft portion of the pile hole, and D indicates the stage of excavation of the expanded bottom by the expanded bottom excavation mechanism 4. E
Indicates the stage of the primary slime treatment after the completion of drilling. This primary slime treatment is usually performed using a bottom dredge bucket as a bottom dredge for removing digging debris and slime settled at the bottom of the hole.

[0005] Fig. 6F shows a stage in which the reinforcing cage 5 is erected in the pile hole, and G shows a stage in which the presence and amount of the slime are measured by inserting the tremy tube 6 into the center. FIG. 6H shows the stage of the secondary slime treatment. This secondary slime treatment is performed by using a submersible pump method or an air lift method that sucks and removes sedimentation slime out of the hole using the tremy tube 6, or mechanically sediments using a stirring blade or the like. Various processes such as stirring the slime to remove the slime out of the hole are performed.

For example, Japanese Patent Application Laid-Open No. Sho 52-8610 discloses a method of slime treatment using an air lift pump, which is disclosed in Japanese Patent Application Laid-Open No. 58-98525 and Japanese Patent Publication No. 6-19.
No. 136 discloses a method of removing slime by injecting a water jet from a lower end of a tremy tube. Japanese Patent Application Laid-Open No. Hei 5-247940 discloses a method of sucking and removing slime through a slime processing pipe using a suction pump or the like.

FIG. 6I shows a stage in which concrete is sequentially poured from the bottom of the hole by the tremy tube 6 immediately after the secondary slime treatment is performed. And
Immediately after the completion of the concrete casting, the pillars 7 are erected as shown in FIG. 6J, and then the casing 2 is pulled out and backfilled 8 as shown in FIG.

[0008]

As is clear from the conventional construction procedure shown in FIGS. 6A to 6K, in the secondary slime treatment (FIG. 6H), at most, the range in which sedimentation slime can be sucked from the tip of the tremie pipe is at most. Since there is nothing except the reinforcing bar 5 in the pile hole (especially the center is widely open), the tip of the tremee pipe is moved evenly over the entire bottom of the hole to reduce the sedimentation slime as much as possible. Perform so as to eliminate the suction. And it is a condition that concrete placement is immediately proceeded after the secondary slime treatment.

[0009] However, when a straight pillar (or a structural steel frame of a normal steel-framed reinforced concrete structure, hereinafter referred to as a long steel frame), which is the theme of the present invention, is long enough to reach the hole bottom. Because of its length, it is necessary to pre-install a long steel frame at an appropriate position before placing concrete.

Therefore, the construction procedure in that case is as follows:
Immediately after the secondary slime treatment, a long steel frame is erected and immediately proceed to the concrete casting process.After the long steel frame is erected, the second slime treatment is performed and concrete is cast. There is no choice but to choose one of the steps to go to.

However, the above-mentioned procedure is a long steel frame, so that the building process takes a long time, during which time the slime is settled again. As described in detail in the section of the related art, it is a condition that the existing secondary slime treatment is performed in a state where there is nothing other than the reinforcing rod cage in the pile hole and the hole center is widely open. In other words, the tip of the tremy tube cannot be moved to the entire bottom of the hole when the long steel frame is in the way, so much of the slime that has settled at the bottom of the hole will remain and be completely removed. Since there is no method or means to perform the procedure at present, it is difficult to implement the procedure.

[0012] The procedure of the above is also based on the fact that there is no secondary slime treatment method and means for completely removing the slime settled at the bottom of the hole in the state where the obstructive long steel frame is built in the pile hole. Again, implementation of this procedure is also difficult.

An object of the present invention is to perform a secondary slime treatment in an excavated pile hole, and then, after the secondary slime treatment, on the premise that a long steel frame is erected before concrete placing. By providing a construction method for cast-in-place concrete piles that can be used to prevent the slime from sinking to the bottom of the hole before concrete placement and ensure sufficient tip support performance and soundness. is there.

A second object of the present invention is to prevent the slime from settling at the bottom of the hole by convection or circulation of the stable liquid in the hole at a predetermined flow rate from after the secondary slime treatment to concrete placement. Cast-in-place concrete piles with long steel frames to secure the tip support performance of piles and to prevent slime from being mixed into concrete and reducing its quality by removing slime at the same time. Is to provide a construction method.

[0015]

According to a first aspect of the present invention, there is provided a method for constructing a long cast-in-place concrete pile, comprising: excavating a pile hole in the ground; In the construction method of cast-in-place concrete piles constructed by embedding and reinforcing steel, and further embedding steel frames, the excavation of pile holes A slime treatment pipe is installed at an arrangement located on the outer periphery of the basket, a secondary slime treatment is performed after the reinforcing cage is built, and then the slime is suspended in the stable liquid through the slime treatment pipe. The tertiary slime treatment is started, and while the tertiary slime treatment is continued, a long steel frame that reaches the bottom of the pile is erected at the center of the pile hole, and concrete is poured from the bottom of the hole using a tremy tube or the like. Open Quickly exit the tertiary slime treatment after, to recover the slime treatment pipe to the ground and, respectively, characterized in that to complete the concreting.

According to a second aspect of the present invention, in the method for constructing a cast-in-place concrete pile for inserting a long steel frame according to the first aspect, the slime is suspended in a stable liquid through a slime treatment pipe. The slime treatment is characterized in that the slime treatment pipe is an air pipe having an air blowing hole at the tip, and compressed air is supplied to the air pipe from the ground, and the stable liquid is convected by rising air bubbles. .

According to a third aspect of the present invention, in the method for constructing a cast-in-place concrete pile for inserting a long steel frame according to the first aspect, the slime is suspended in a stable liquid through a slime treatment pipe. The slime treatment is characterized in that a submersible pump is connected to the upper part of the slime treatment pipe, and the submersible pump is operated to suck the stable liquid from the pipe tip and return to the hole at the pile head for convection.

According to a fourth aspect of the present invention, there is provided a method for constructing a cast-in-place concrete pile into which a long steel frame according to the first aspect is put. A third slime treatment in which slime is suspended in a stable liquid through a slime treatment pipe. Connects the upper part of the slime treatment pipe to the pump and the slime removal tank, sucks the stable liquid from the end of the pipe, returns it to the slime removal tank, and then returns the stable liquid from the tank to the hole at the pile head. And circulate it.

According to a fifth aspect of the present invention, in the method for constructing a cast-in-place concrete pile into which a long steel frame is to be put according to the first aspect, a slime is suspended in a stable liquid through a slime treatment pipe. The slime treatment is characterized in that the stable liquid sucked from the pile head is returned to the slime removal tank, and then the stable liquid discharged from the tank is supplied from the tip of the slime processing pipe to the vicinity of the hole bottom and circulated.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a cast-in-place concrete pile construction method for inserting a long steel frame according to the first aspect of the present invention in the order of essential steps. However, the present invention also excavates a pile hole in the ground, treats slime,
Since this is a construction method of a cast-in-place concrete pile in which a steel cage is built and a steel frame is further built, the method is common to the conventional example of FIG. Therefore, FIG. 1 omits the illustration of the common first half process. 1a to 1g show the stage of the first slime treatment process.

That is, after the pile hole 10 is excavated and subjected to a primary slime treatment as shown in FIG. 1A by a well-known bottom dredge or other method, the arrangement located on the outer periphery of the steel cage 5 in the pile hole 10 will be described. Then, one or more slime treatment pipes 11 are inserted and installed in advance in an appropriate arrangement for the secondary slime treatment (FIG. 1b).

Subsequently, as shown in FIG. 1c, the reinforcing bar cage 5 is built. Furthermore, a known secondary slime process is performed in which the tremy tube 6 is inserted into the center of the pile hole and the slime that has settled to the bottom of the hole is removed by suction using the tremy tube 6 (FIG. 1d).

Immediately thereafter, a third slime treatment for preventing the slime from floating in the stabilizing solution and settling through the slime treatment pipe 11 will be described in detail below.
Start with the trick. While continuing the state of the tertiary slime treatment, a long steel frame 7 that is long enough to reach the bottom of the pile hole 10 is provided in the center of the pile hole 10 in parallel with the tremy tube or in a relationship to replace the tremy tube. To the depth of the building (Fig. 1
e).

Thereafter, concrete casting is started in order from the bottom of the hole by the tremy tube 6 or the like built in parallel with the long steel frame 7. Before the slime processing pipe 11 is buried in the top end of the cast concrete 12, the tertiary slime processing is immediately terminated, and the slime processing pipe 11 is pulled up and collected on the ground. The concrete is cast and completed (Fig. 1
f).

Therefore, after the secondary slime treatment, until the concrete casting step starts, the slime is reliably prevented from settling at the bottom of the hole by the third slime treatment. Therefore, it is possible to construct an SRC cast-in-place concrete pile having excellent tip support performance and good quality without being affected by slime.

Finally, as shown in FIG. 1g, the casing 2 is pulled out and backfilled 8 to complete the SRC cast-in-place concrete pile, which is the same as the prior art shown in FIG.

By the way, the third slime treatment for suspending the slime in the stabilizing liquid through the slime processing pipe 11 so as not to settle out as described above is based on the method of convection or circulation of the stabilizing liquid as a whole. It is implemented as follows.

First, FIG. 2 shows a slime processing pipe 11.
Is configured as an air pipe having an air blowing hole at the tip end, and a processing method in which compressed air is supplied to the air pipe from the ground and a stable liquid is convected by rising air bubbles (claim 2). invention).

FIG. 3 shows that a submersible pump 13 is installed above the slime processing pipe 11, and the submersible pump 13 is operated to suck a stable liquid from the tip of the slime processing pipe 11, and the stable liquid is sucked at the pile head. This shows a processing method of returning to the inside of the hole and causing convection downward from above (the invention according to claim 3).

In FIG. 4, the upper part of the slime treatment pipe 11 is connected to a slime removal tank 14 including a suction pump, and the stable liquid is sucked from the tip of the slime treatment pipe 11 and returned to the slime removal tank 14. Then, there is shown a processing method in which the stable liquid discharged from the tank 14 after the removal of the slime is supplied into the hole at the pile head and the entire stable liquid in the hole is circulated from top to bottom. Item 4).

FIG. 5 shows that the stable liquid sucked from the pile head by the submersible pump 13 is also returned to the slime removal tank 14.
Then, a processing method is shown in which the stable liquid that is removed from the tank 14 after removing the slime is supplied from the tip of the slime processing pipe 11 to the vicinity of the bottom of the hole, and the stable liquid in the hole is circulated from bottom to top. (The invention according to claim 5).

[0032]

According to the present invention, there is provided a method for constructing a cast-in-place concrete pile in which a long steel frame is inserted according to the present invention, wherein the long steel frame is inserted immediately after the secondary slime treatment.
Until the concrete is poured, the slime is suspended in the stabilizing liquid by the tertiary slime treatment to prevent the slime from settling at the bottom of the hole. And SRC cast-in-place concrete piles with high quality and soundness can be constructed.

In particular, after the elaborate primary and secondary slime treatments, the slime floating in the stabilizing solution is mainly composed of fine-grained soil, and therefore easily floats even at a small flow rate. Therefore, even if the long steel frame is present and the empty space is small, it is possible to reliably prevent the slime from settling at the bottom of the hole due to the convection or circulation of the stable liquid. Not only at the bottom of the hole, but also when there is a protrusion or an enlarged diameter portion at the shaft portion of the pile hole, it does not settle there. In addition, no special equipment is required for the tertiary treatment for preventing slime sedimentation, and it can be performed with relatively simple equipment without requiring a new work space.

[Brief description of the drawings]

1 (a) to 1 (g) are explanatory diagrams sequentially showing the essential steps of a construction method according to the first aspect of the present invention.

FIG. 2 is a plan view and a cross-sectional view illustrating an embodiment of a third slime treatment.

FIG. 3 is a plan view and a cross-sectional view showing different embodiments of the third slime processing.

FIG. 4 is a plan view and a sectional view showing different embodiments of the third slime processing.

FIG. 5 is a plan view and a sectional view showing still another embodiment of the third slime processing.

FIGS. 6A to 6K are explanatory diagrams sequentially showing essential steps of a conventional construction method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pile hole 5 Reinforcing cage 11 Slime processing pipe 7 Long steel frame 6 Toremy pipe 12 Concrete 13 Submersible pump 14 Slime removal tank 8 Damping device

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Minoru Okahashi 1-5-1, Otsuka, Inzai City, Chiba Prefecture Inside the Technical Research Center, Takenaka Corporation (72) Inventor Masao Maruoka 1-5-1, Otsuka, Inzai City, Chiba Prefecture Inside Takenaka Corporation Technical Research Institute (72) Inventor Eiichi Kawamoto 8-21-1, Ginza, Chuo-ku, Tokyo Inside Tokyo Headquarters Takenaka Corporation (72) Inventor Toshiaki Tsuchiya Ginzahachi, Chuo-ku, Tokyo No. 21-1, Takenaka Corporation Tokyo Main Branch (72) Inventor Toshiro Mori 8-21-1, Ginza, Chuo-ku, Tokyo F-Terminal, Takenaka Corporation Tokyo Main Store F-term (reference) 2D041 AA01 BA14 BA44 DA03 EA04 EB02 2D045 AA02 AA04 BA04 CA11 CA23

Claims (5)

[Claims] 1. A method for constructing a cast-in-place concrete pile constructed by excavating a pile hole in the ground, treating slime, embedding a reinforcing bar, and further embedding a steel frame. A pipe for slime treatment is installed in the pile hole that has been subjected to the following slime treatment in an arrangement located on the outer periphery of the reinforcing rod cage, and the secondary slime processing is performed after the reinforcing cage is built, and then the slime processing is performed. Initiate the third slime treatment to make the slime float in the stable liquid through the pipe, and continue the third slime treatment, and reach the bottom of the hole at the center of the pile hole with a long steel frame After the concrete is started to be poured from the bottom of the hole using a tremy tube or the like, the tertiary slime treatment is immediately terminated, and the slime processing pipe is collected on the ground to complete the concrete placement. Construction method of cast-in-place concrete pile to put long steel frame. 2. A third slime treatment in which the slime floats in the stabilizing solution through the slime treatment pipe,
The slime processing pipe is an air pipe having an air outlet at an end thereof, and compressed air is supplied to the air pipe from the ground so that a stable liquid is convected by rising air bubbles. Construction method of cast-in-place concrete pile to put long steel frame described in section. 3. A third slime treatment in which the slime is suspended in the stabilizing solution through the slime treatment pipe,
The submersible pump is connected to the upper part of the slime processing pipe, and the submersible pump is operated to suck the stable liquid from the pipe tip and return to the inside of the hole at the pile head for convection. Construction method of cast-in-place concrete piles for placing long steel frames. 4. A third slime treatment in which slime is suspended in a stabilizing solution through a slime treatment pipe,
The upper part of the slime treatment pipe is connected to a pump and a slime removal tank, and the stable liquid is sucked from the end of the pipe and returned to the slime removal tank, and then the stable liquid coming out of the tank is supplied into the hole at the pile head The method for constructing a cast-in-place concrete pile into which a long steel frame is inserted according to claim 1, wherein the pile is circulated. 5. The third slime treatment in which the slime floats in the stabilizing solution through the slime treatment pipe,
The method according to claim 1, wherein after returning the stable liquid sucked from the pile head to the slime removal tank, the stable liquid discharged from the tank is supplied from the tip of the slime processing pipe to the vicinity of the hole bottom and circulated. Construction method of cast-in-place concrete pile to insert long steel frame described.