JP2011052525A - Cast-in-place pile construction method and cast-in-place pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an cast-in-place pile construction method which reduces a concrete amount, and reduces a soil amount discharged from a site. <P>SOLUTION: A pile hole 20 is drilled, a soil generated by the drilling is stored in a plurality of bag bodies 21, a reinforcement cage 10 is inserted into the drilled pile hole 20, and the plurality of bag bodies 21 is fed inside the reinforcement cage 10. The concrete amount equal to a volume of a fed soil amount is reduced by feeding the soil produced by the drilling inside the reinforcement cage 10. Then, a material cost and a placing cost are reduced regarding concrete. The soil amount discharged from the site is also reduced by the fed soil amount. A treatment cost and a loading cost are reduced as well. A working cost required for constructing the cast-in-place pile 1 is remarkably reduced by this manner. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cast-in-place pile construction method and cast-in-place pile.

Conventionally, cast-in-place concrete piles (hereinafter referred to as cast-in-place piles) are often used as the foundation of high-rise buildings.
As a method for constructing a cast-in-place pile, for example, there are an earth drill method, an all-casing method, and a reverse circulation method. In the building field, an earth drill method is often adopted.

Here, when building cast-in-place piles, in order to reduce the amount of concrete used for the piles and reduce construction costs, a hollow bag body extending along the central axis of the pile hole is provided inside the reinforcing bar A method of press-fitting water or compressed air into the bag has been proposed (see Patent Document 1).
According to this invention, it is possible to reduce the construction cost by reducing the amount of concrete by the volume of the bag.

JP-A-5-132929

  Incidentally, in recent years, it has been requested to reduce the amount of soil discharged from the site from the viewpoint of increasing environmental awareness and reducing construction costs. However, according to the technique disclosed in Patent Document 1, since the compressed air is pressed into the bag body, the amount of concrete can be reduced, but it has been difficult to reduce the amount of soil discharged from the site.

  Furthermore, in recent years, the number of large-sized structures has increased, so there is a tendency for cast-in-place piles to have a larger diameter, and this increases the amount of soil generated during excavation. Costs also increased.

  An object of the present invention is to provide a cast-in-place pile construction method and cast-in-place pile that can reduce the amount of concrete and reduce the amount of soil discharged from the site.

  The cast-in-place pile construction method according to claim 1 includes a step of excavating a pile hole, a step of accommodating a processing object in a bag body, a step of inserting a reinforcing bar into the excavated pile hole, and the bag body And a step of throwing the inside of the reinforcing bar cage.

  Here, the processing object means an object that is generated on the site and needs to be disposed as it is or after performing some kind of processing, and examples thereof include soil, sludge, concrete waste, and the like.

  The cast-in-place pile construction method according to claim 2 is characterized in that the processing object is soil generated by excavation.

According to this invention, the amount of concrete having a volume equal to the amount of the processing object that has been input can be reduced by supplying the processing object to the inside of the reinforcing bar. As a result, for concrete, not only material costs but also placement costs can be reduced.
Further, the amount of the processing object discharged from the site can be reduced by the amount of the processing object that has been input. As a result, not only the processing cost but also the loading effort can be reduced.
As mentioned above, the construction cost concerning construction of a cast-in-place pile can be reduced significantly.

Moreover, since the shape of the pile is a cylindrical outer shell structure, the amount of concrete can be greatly reduced as compared with the case of a solid structure as in the prior art.
In addition, since the area of the outer peripheral surface of the pile is the same as that in the case of a solid structure, the supporting force of the pile is reduced without reducing the supporting force of the pile determined by the frictional force between the outer peripheral surface of the pile and the ground. Can be secured sufficiently.
Moreover, since the process target object was thrown into the inside of a reinforcing steel cage | basket | car, the decreasing rate of a cross-sectional secondary moment can be made small with respect to the decreasing rate of the concrete amount of a pile.

In addition, since conventional heavy machinery and equipment such as casing, auger, and stabilizing liquid can be used, it is not necessary to provide new equipment, and it is possible to suppress an increase in construction costs of heavy machinery and equipment.
In addition, similar to the conventional cast-in-place pile method, it is possible to construct on gravel ground and soft ground where the hole wall tends to collapse.

By the way, in a structure that performs snow melting and heating using geothermal heat, equipment piping may be installed near the outer periphery of a pile close to soil. In this case, in the conventional on-site pile, in order to ensure the cross-sectional area of the structure part of a pile, it was necessary to add concrete about 200 mm.
However, according to the present invention, the equipment piping can be accommodated together with the bag inside the reinforcing bar cage, so there is no need to increase the amount of concrete.

  Conventionally, when installing equipment piping, supporting tools such as reinforcing bars, strips, and spacers are provided on the outer periphery of the main reinforcing bars, and the equipment piping is supported by the supporting tools. Thus, since the support tool for maintaining a hollow shape already exists, since equipment piping can be held using this support tool, equipment piping can be easily held.

In addition, if the processing object is divided into a plurality of bags and put into the holding part, it is easy to enclose the processing object inside the bag, and the work of putting the bag into the pile hole after excavation is easy. As a result, workability is improved. Moreover, the bag body can be filled with soil densely, making it difficult to lose shape.
Since the processing object is packed in the bag body on the ground, the shape of the bag body can be easily held, and transportation and storage on the ground are easy.
Since the volume of the bag body hardly changes after enclosing the object to be treated, the amount of concrete reduction can be considered to be almost equal to the input amount of the bag body. The amount can be easily confirmed.
Since the bag body in which the object to be treated is sealed has a certain level of strength, the bag body can be used as an auxiliary to resist external forces such as compression and shearing.

  The cast-in-place pile construction method according to claim 3 is provided with a cylindrical holding portion extending along the inside of the reinforcing bar cage, and when the bag body is placed inside the reinforcing bar cage, It is made to hold | maintain inside the said holding | maintenance part.

  According to this invention, the cylindrical holding | maintenance part extended along the inner side of a reinforcing bar cage | basket was provided, and when putting a bag body inside the reinforcing bar cage | basket, the bag body was hold | maintained inside the holding | maintenance part. Therefore, the bag can be smoothly put into a predetermined position inside the reinforcing bar cage.

  The cast-in-place pile construction method according to claim 4 is characterized in that the holding portion is assembled with a reinforcing bar.

  According to the present invention, when assembling the holding portion, tools and equipment for assembling the reinforcing bar can be used, so that the cost for assembling the holding portion can be reduced.

  The cast-in-place pile according to claim 5 is characterized in that a bag body that accommodates an object to be processed is accommodated inside the reinforcing bar.

  According to the present invention, there is an effect similar to that of the first aspect.

  The cast-in-place pile according to claim 6 is characterized in that the processing object is soil generated by excavation.

  According to the present invention, there is an effect similar to that of the second aspect described above.

  The cast-in-place pile according to claim 7 is characterized in that a holding portion is provided inside the reinforcing bar and the bag body is held inside the holding portion.

  According to the present invention, there is an effect similar to that of the third aspect described above.

  The cast-in-place pile according to claim 8 is characterized in that the holding portion is assembled with a reinforcing bar.

  According to the present invention, there is an effect similar to that of the above-described fourth aspect.

  According to the present invention, the amount of concrete having a volume equal to the amount of the charged processing object can be reduced by charging the processing object inside the reinforcing bar. As a result, for concrete, not only material costs but also placement costs can be reduced. Further, the amount of the processing object discharged from the site can be reduced by the amount of the processing object that has been input. As a result, not only the processing cost but also the loading effort can be reduced.

It is a perspective view of the reinforcing steel cage used for the cast-in-place pile which concerns on 1st Embodiment of this invention. It is FIG. (1) for demonstrating the procedure which builds the cast-in-place pile which concerns on the said embodiment. It is FIG. (2) for demonstrating the procedure which builds the cast-in-place pile which concerns on the said embodiment. It is a partial side view of the holding | maintenance part used for the cast-in-place pile which concerns on 2nd Embodiment of this invention. It is a side view which shows the relationship between the holding | maintenance part which concerns on the said embodiment, and a reinforcing steel basket. It is FIG. (1) for demonstrating the procedure which builds the cast-in-place pile which concerns on the said embodiment. It is FIG. (2) for demonstrating the procedure which builds the cast-in-place pile which concerns on the said embodiment. It is FIG. (3) for demonstrating the procedure which constructs the cast-in-place pile which concerns on the said embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted or simplified.
[First Embodiment]
FIG. 1 is a perspective view of a reinforcing bar 10 used for a cast-in-place pile according to the first embodiment of the present invention.
The reinforcing bar 10 has a cylindrical shape, and includes twelve main bars 11 extending in the axial direction and a plurality of annular band bars 12 wound around the main bars 11 at predetermined intervals.
A holding portion 13 extending along the central axis is provided inside the reinforcing bar 10. The holding portion 13 is attached to the band 12 via a support tool 14.
The holding portion 13 includes a substantially cylindrical wall portion 131 and a conical bottom lid 132 that closes the tip of the wall portion 131.

Hereinafter, the procedure for constructing a cast-in-place pile using the ground drill expansion method will be described with reference to FIGS. 2 and 3.
First, in step S1, as shown in FIG. 2 (a), the ground 2 is drilled with a drilling bucket while stabilizing the hole wall using a stabilizing liquid such as bentonite, and further, the tip of the hole is predetermined with an expanded bucket. The shape is formed. Thereby, the pile hole 20 is formed in the ground.
In addition, a plurality of bag bodies 21 are prepared on the ground, and soil as a processing object generated by excavation of the pile holes 20 is enclosed in these bag bodies 21.
Moreover, what the above-mentioned rebar cage | basket | car 10 was divided | segmented for every predetermined length to the axial direction is made into a rebar cage | basket unit, and this reinforcing bar cage | basket unit is manufactured in a reinforcing bar yard.

  In step S <b> 2, as shown in FIG. 2 (b), the rebar basket unit is lifted with a crane and inserted into the pile hole 20. By repeating this operation, the rebar cage units are connected in the axial direction in the pile hole 20 to construct the rebar cage 10.

In step S <b> 3, as shown in FIG. 2C, the two tremy tubes 22 are inserted into the pile hole 20 so as to be located on the diagonal line of the cross section of the pile hole 20, and the pile hole 20 is passed through the tremy tube 22. Put concrete on the tip of the. Thereby, the position of the reinforcing steel basket 10 is fixed.
At this time, the conical bottom cover 132 allows the concrete to smoothly wrap around the tip of the pile hole 20.

  Then, the bag body 21 filled with soil is put into the holding portion 13 of the reinforcing bar 10. At this time, the wall portion 131 of the holding portion 13 serves as a guide when the bag body 21 is inserted. Moreover, the height from the concrete upper surface of the bag body 21 to pile up is set to such an extent that the holding | maintenance part 13 does not buckle with the pressure to the side which generate | occur | produces with the dead weight of the bag body 21. FIG. Specifically, in this embodiment, the bag body 21 is piled up by four steps from the concrete upper surface.

  In step S4, as shown in FIG. 3A, the tremy tube 22 is raised to some extent, and then concrete is laid through the tremy tube 22 to the height of the bag body 21 already stacked. Then, as in step S3, a predetermined amount of the bag body 21 filled with soil is put into the holding portion 13 of the reinforcing bar 10.

  In step S5, by repeating the work of step S4, as shown in FIG. 3B, concrete is cast to a predetermined depth, and the cast-in-place pile 1 is constructed.

  In step S6, the remaining soil is backfilled as shown in FIG.

According to this embodiment, there are the following effects.
(1) By putting the soil generated by excavation inside the reinforcing bar 10, it is possible to reduce the amount of concrete having a volume equal to the amount of soil introduced. As a result, for concrete, not only material costs but also placement costs can be reduced.
In addition, the amount of soil discharged from the site can be reduced by the amount of soil input. As a result, not only the processing cost but also the loading effort can be reduced.
As mentioned above, the construction cost concerning construction of cast-in-place pile 1 can be reduced significantly.

Moreover, since the shape of the cast-in-place pile 1 becomes a cylindrical outer shell structure, the amount of concrete can be significantly reduced compared with the case where it is made into a solid structure like the past.
Moreover, since the area of the outer peripheral surface of the cast-in-place pile 1 is the same as the case where it is set as a solid structure, the support force of the pile determined by the frictional force of the outer peripheral surface of the cast-in-place pile 1 and the ground 2 reduces. Without being able to secure the bearing capacity of the pile.
Moreover, since the soil generated by excavation is put inside the reinforcing bar 10, the reduction rate of the cross-sectional secondary moment can be reduced with respect to the reduction rate of the concrete amount of the pile.

In addition, since conventional heavy machinery and equipment such as casing, auger, and stabilizing liquid can be used, it is not necessary to provide new equipment, and it is possible to suppress an increase in construction costs of heavy machinery and equipment.
In addition, similar to the conventional cast-in-place pile method, it is possible to construct on gravel ground and soft ground where the hole wall tends to collapse.

Further, since the soil generated by excavation is divided into a plurality of bag bodies 21 and put into the holding portion, the soil is easily enclosed in the bag body 21 and the bags are put into the pile holes 20 after excavation. Work becomes easy and workability improves. Moreover, the bag body 21 can be filled with soil densely, and it becomes difficult to lose its shape.
Since the bag body 21 is filled with soil generated by excavation on the ground, the shape of the bag body 21 can be easily maintained, and transportation and storage on the ground are easy.
Since the volume of the bag body 21 hardly changes after enclosing the soil generated by excavation, it can be considered that the reduction amount of concrete is substantially equal to the input amount of the bag body. The amount of concrete placement can be easily confirmed.
Since the bag body 21 enclosing the soil generated by excavation has a certain level of strength, the bag body can be used as an auxiliary to resist external forces such as compression and shearing.

  (2) A cylindrical holding portion 13 extending along the inside of the reinforcing bar cage 10 is provided, and when the bag body 21 is put inside the reinforcing rod cage 10, the bag body 21 is put inside the holding portion 13. Therefore, it is possible to prevent the bag body 21 from being caught by the reinforcing bars of the reinforcing bar cage 10, and to smoothly put the bag body 21 into the reinforcing bar cage 10.

  (3) Since the soil enclosed in the bag body 21 is the soil generated when excavating the pile hole 20, the soil generated during the construction of the cast-in-place pile can be efficiently reused on site and carried out of the field. As much as possible.

[Second Embodiment]
In the present embodiment, the structure of the holding portion 13A is different from that of the first embodiment.
FIG. 4 is a side view of a part of the holding portion 13A used in the cast-in-place pile according to the second embodiment of the present invention.
13 A of holding | maintenance parts are the some holding | maintenance part units 30 connected with the axial direction.
Each holding unit 30 includes a holding unit main body 31 assembled in a cylindrical shape with reinforcing bars, and one bag body 32 provided inside the holding unit main body 31.
The holding portion main body 31 includes a plurality of axial bars 33 extending in the axial direction, a plurality of annular strips 34 wound around the axial bars 33 at predetermined intervals, and a predetermined position outside the axial bars 33. Three annular reinforcing bars 35 wound on the outer periphery, and spacers 36 provided at four locations on the base end side outer periphery.

FIG. 5 is a side view showing the relationship between the holding portion 13A and the reinforcing steel basket 10A.
An annular reinforcing ring 16 is provided inside the main bar 11 of the reinforcing bar 10A at predetermined intervals in the length direction.

  When the above holding portion 13A is inserted into the reinforcing bar cage 10A, the spacer 36 of the holding portion 13A abuts the inside of the reinforcing ring 16 of the reinforcing bar cage 10A, so that the relative position of the holding portion 13A with respect to the reinforcing bar cage 10A is determined. 13A is located on the central axis of the reinforcing steel basket 10A.

Hereinafter, a procedure for constructing a cast-in-place pile using an earth drill bottom expanding method will be described with reference to FIGS.
On the ground, the soil generated by excavation of the pile hole 20 is enclosed in the bag body 32 of the holding unit 30. Further, the reinforcing bar 10A is divided into three parts in a predetermined length in the axial direction to form the lowermost, middle, and uppermost reinforcing bar units 17, respectively. These three reinforcing bar units 17 are formed in the reinforcing bar yard. Make it.

First, in step S1, as shown in FIG. 6 (a), the ground 2 is drilled with a drilling bucket while stabilizing the hole wall using a stabilizing liquid such as bentonite, and the tip of the hole is predetermined with an expanded bucket. The shape is formed. Thereby, the pile hole 20 is formed in the ground.
Further, the lowermost reinforcing steel cage unit 17 is lifted with a crane and inserted into the pile hole 20.

  In step S <b> 2, as shown in FIG. 6B, the holding unit 30 is lifted with a crane and inserted into the lowermost reinforcing steel basket unit 17 in the pile hole 20. This operation is repeated twice to insert the two holding unit 30.

  In step S <b> 3, as shown in FIG. 6C, the intermediate reinforcing bar car unit 17 is lifted by a crane, inserted into the pile hole 20, and connected to the lowermost reinforcing bar car unit 17. Thereafter, the rebar basket unit 17 connected is settling by a predetermined amount.

  In step S <b> 4, as shown in FIG. 7A, the holding unit 30 is lifted by a crane and inserted into the reinforcing bar unit 17 at the intermediate portion of the pile hole 20. This operation is repeated three times to insert the three holding unit 30.

  In step S5, as shown in FIG. 7 (b), the uppermost rebar basket unit 17 is lifted with a crane, inserted into the pile hole 20, and connected to the intermediate bar basket unit 17. Thereafter, the connected reinforcing steel bar unit 17 is further settled by a predetermined amount.

  In step S <b> 6, as shown in FIG. 7C, the holding unit 30 is lifted with a crane and inserted into the uppermost reinforcing steel cab unit 17 of the pile hole 20. This operation is repeated three times to insert the three holding unit 30.

  In this way, the rebar car unit 17 is connected in the axial direction, the rebar car 10 is constructed in the pile hole 20, and the holding unit 30 is connected in the axial direction so that the holding part 13 </ b> A is placed inside the rebar car 10. Build up.

  In step S7, as shown in FIG. 8A, the constructed reinforcing steel cage 10A is further settling by a predetermined amount. Subsequently, the two tremely pipes 22 are inserted into the pile hole 20 so as to be positioned on the diagonal line of the cross section of the pile hole 20, and concrete is driven through the tremey pipe 22 to the tip of the pile hole 20.

  In step S8, by repeating the operation of placing concrete while pulling up the trememy tube 22, the concrete is cast to a predetermined depth as shown in FIG. 8B, and the cast-in-place pile 1A is constructed. Then refill the remaining soil.

  According to this embodiment, the same effects as the above (1) to (3) are obtained.

  Note that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope in which the object of the present invention can be achieved are included in the present invention.

  For example, equipment piping may be embedded in the cast-in-place pile 1. In this case, the equipment piping can be accommodated inside the reinforcing bar 10 together with the bag, so that it is not necessary to increase the amount of concrete. Moreover, since the support tool 14 for maintaining the hollow shape already exists, the equipment pipe can be held by using the support tool 14, and therefore the equipment pipe can be easily held.

  Further, in the first embodiment, the reinforcing bar 10 is completely inserted into the pile hole 20, and then the bag body 21 is introduced into the holding portion 13 of the reinforcing bar 10 by a predetermined amount, and this already stacked bag body. Although the procedure of placing concrete up to a height of 21 was repeated, this is not restrictive. That is, the procedure in which the reinforcing bar 10 is inserted into the pile hole 20 by a predetermined size and the bag body 21 is inserted into the holding part 13 of the reinforcing bar 10 by a predetermined amount is repeated, and then the concrete is cast once. May be.

DESCRIPTION OF SYMBOLS 1, 1A Cast-in-place pile 2 Ground 10, 10A Reinforcement basket 11 Main reinforcement 12 Band reinforcement 13, 13A Holding part 14 Supporting tool 15 Reinforcement basket 16 Reinforcement basket unit 161 Reinforcement ring 20 Pile hole 21 Bag body 22 Tremy tube 30 Holding part unit 31 Holding unit body 32 Bag 33 Axle bar 34 Band bar 35 Reinforcement bar 36 Spacer 131 Wall part 132 Bottom cover

Claims (8)

A process of drilling a pile hole;
A process of accommodating a processing object in a bag;
Inserting a rebar cage into the excavated pile hole;
Placing the bag into the inside of the rebar cage, and a method for constructing a cast-in-place pile. In the cast-in-place pile construction method according to claim 1,
The cast-in-place pile construction method, wherein the processing object is soil generated by excavation. In the cast-in-place pile construction method according to claim 1 or 2,
A cylindrical holding portion extending along the inner side of the rebar cage is provided,
A cast-in-place pile construction method, wherein the bag body is held inside the holding portion when the bag body is put inside the reinforcing bar cage. In the cast-in-place pile construction method according to claim 3,
A cast-in-place pile construction method comprising assembling the holding portion with a reinforcing bar.   A cast-in-place pile characterized in that a bag for accommodating a processing object is accommodated inside the reinforcing bar. In the cast-in-place pile according to claim 5,
The cast-in-place pile, wherein the processing object is soil generated by excavation. In the cast-in-place pile according to claim 5 or 6,
A holding portion is provided inside the reinforcing bar cage,
The cast-in-place pile according to claim 5, wherein the bag body is held inside the holding portion. In the cast-in-place pile according to claim 7,
A cast-in-place pile, wherein the holding portion is assembled with a reinforcing bar.

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