JP2002242178A - Cast-in-place pile method and working scaffold for steel bar cage erection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure stable scaffold and improve the safety and workability at the time of work for erecting a steel bar cage. SOLUTION: In a cast-in-place pile driving method in which a stand pipe 3 is pressed in by a power jack 2 and a steel bar cage 7 is erected in a pile hole, a detachable steel bar cage erection work scaffold 30 is installed on the power jack 2 after pile hole excavation and before steel bar cage erection work. The steel bar cage erection work scaffold 30 bas a stand pipe inserted to a central hole and loaded to the power jack 2 in a situation where the scaffold is supported by four main cylinders 21 positioned at equal intervals in the vicinity of the stand pipes 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cast-in-place pile method and, more particularly, to a scaffold used in a reinforced cage construction work.

[0002]

2. Description of the Related Art Cast-in-place piles are site-built piles in which a steel cage is inserted into a hole in which the ground is excavated, and concrete is cast and built. Cast-in-place pile method includes all casing method, earth drill method, reverse circulation method and the like, and these methods are widely used in Japan. These methods may be used together. In the all-casing method (also known as the Venoto method), the casing is rocked and pressed while excavating the inside of the cylindrical casing with a hammer rub or the like, and the digging is performed while protecting the hole wall with the casing. After the excavation, a steel cage is erected in the casing and the casing is pulled out while casting concrete to form a pile. In the earth drilling method, a cylindrical body called a stand pipe (or surface casing, mouth casing) is installed near the surface of the ground, and a bentonite stabilizing solution is applied in the hole to protect the hole wall, and the rotation is attached to the tip of the rotating shaft. Excavation is performed by bucket. After the excavation is completed, a steel cage is built and concrete is cast to create a pile. In the reverse circulation method, a stand pipe is installed near the surface of the ground, the ground is excavated with a rotating bit at the tip of the drilling pipe, muddy water is pumped up from the drilling pipe, mud is discharged, muddy water flows back into the hole, and the water is recirculated. Creates a circulation and protects the hole walls with water pressure. The stand pipe has a role as a retaining wall near the surface of the ground.

As described above, in the method of constructing a cast-in-place pile,
Generally, an all casing inserted into the whole pile hole and a stand pipe inserted to a shallow place near the mouth of the hole are generally used. Generally, these cylindrical bodies are press-fitted by a power jack. An example of such a conventional method will be described below.

[0004] Fig. 5 shows a reverse circulation drill construction sequence diagram. (A) First, the stand pipe 3 is press-fitted with the power jack 2 and the stand pipe 3 is built. A weight 5 is mounted on a weight table 4 around the power jack 2.
The stand pipe is buried, for example, about 10 m from the surface of the ground, and is sufficiently inserted to a stable impermeable layer below the groundwater level. (B) Next, the inside of the stand pipe 3 is excavated by the hammer grab 9. (C) Thereafter, a reverse excavator (not shown) is installed. At this time, a rotary table 11 for supporting the drilling pipe 10 is installed on the stand pipe 3 and fixed to a power jack (not shown) with a chain block (not shown). (D) Subsequently, reverse excavation is performed to a desired depth, and (e)
After the measurement and the slime treatment, (f) the reinforcing rod cage 7 is built.
FIG. 6 shows a front view of a conventional example of a reinforced cage construction work scene. As shown in FIG. 6, the power jack 2 is installed,
A standpipe 3 is built. A weight 5 is mounted on a weight table 4 provided beside the base 1. As shown in FIG. 6, the power jack 2 includes a main cylinder 21 which expands and contracts in a vertical direction for press-fitting the stand pipe 3, a main tightening band 22 and a sub tightening band which tighten and hold the outer peripheral surface of the stand pipe 3. 23, and a main tightening cylinder 24 and a sub-tightening cylinder 25 that respectively drive the tightening bands. When the reinforcing bar cage is built, the worker 6 carries out operations such as connecting the reinforcing bar basket 7 and the reinforcing bar cage 7 with the mechanical joint 8. At this time, the worker 6 is required to hold the main cylinder 21 and the main tightening band 2
2 was working as a foothold. After building the reinforcing bars,
(G) Tremy tube insertion and slime treatment, (h) concrete placing, (i) stand pipe withdrawal, and (j) soil covering and curing.

[0005]

As described above, the worker 6 has been working to build a reinforcing cage using the main cylinder 21 and the main tightening band 22 as scaffolds. Therefore, there was a problem that the scaffold was unstable and safety and workability were not so good. It is possible to attach a fixed scaffold on the power jack 2 in advance and permanently install it, but there are the following problems. At the time of hammer grab excavation, the weights 5 on both sides of the power jack 2 serve as a scaffold for connecting the stand pipe. Therefore, it is not necessary to install a scaffold. Since the main tightening band 22 moves in the horizontal direction, there is a problem that the scaffold must be configured so as not to interfere with the movement. In addition, at the time of drilling pipe connection work during reverse excavation, the rotary table 11 serves as a scaffold, and a fall prevention measure can be taken by attaching a handrail to the end of the rotary table 11, so that the need for scaffold installation is poor, There is a problem that a scaffold must be formed so that the rotary table 11 installed on the casing 3 can be fixed to the power jack 2 with a chain block. Therefore, when a fixed scaffold is previously mounted on the power jack 2 and is permanently installed, there are many restrictions on the scaffold design, and as a result, it is difficult to secure a sufficient scaffold at the time of connecting the reinforcing bar cage.

The present invention has been made in view of the above-mentioned problems in the prior art. In a cast-in-place pile method in which a stand pipe or a casing is press-fitted with a power jack and a reinforcing steel cage is built, a reinforcing steel cage is provided. The objective is to secure a stable scaffolding during construction work and improve safety and workability.

[0007]

Means for Solving the Problems To solve the above problems, the invention described in claim 1 is, for example, as shown in FIG.
In the cast-in-place pile method in which the stand pipe 3 or the casing is press-fitted with the power jack 2 and the reinforcing cage 7 is built in the pile hole, it is detachable on the power jack 2 after drilling the pile hole and before building the reinforcing cage. Scaffolding 3
0 is set.

According to the first aspect of the present invention, a detachable scaffold is installed on the power jack after excavation of the pile hole. That is, the scaffold is not installed during excavation such as hammer grab excavation or reverse excavation. A removable scaffold will be installed on the power jack before the work to build the reinforcing bars without causing any trouble. Can be. When the scaffold is stabilized, safety and workability can be improved.

The invention according to claim 2 can be mounted, for example, on a stand pipe 3 or a power jack 2 for press-fitting a casing in a cast-in-place pile method as shown in FIG. Alternatively, there is provided a rebar basket-building work scaffolding provided with a hole 37 (see FIG. 2) having a size capable of inserting a casing.

According to the second aspect of the present invention, since it can be mounted on a power jack, a work platform can be secured around a stand pipe or a casing (hereinafter, referred to as a stand pipe or the like). In addition, a hole large enough to insert a standpipe etc. is provided.By placing this hole above the standpipe and lowering it, the work scaffold can be easily mounted on the power jack. There is an effect that a scaffold can be quickly and easily formed around a stand pipe or the like. In addition, if the work scaffold is lifted, the work scaffold can be quickly and easily removed. Further, since the stand pipe or the like is inserted into the hole of the work scaffold, the work scaffold does not fall off. In order to prevent the work scaffold from shifting on the power jack, it is preferable to form a hole having a shape and a size that fits on the outer periphery of a stand pipe or the like. For the same purpose, it is preferable to further provide a shift scaffold such as a hole, a frame, or an uneven portion for engaging or fitting with the uneven portion of the main cylinder or the like of the power jack. With the above-described configuration, a work scaffold that is easy to attach and detach, and that is easy to install and remove, and that is excellent in stability can be configured, and workability is improved. In addition, the material that forms the floor of the work scaffold is made of a material that is effective in preventing slippage, such as using expanded metal or other material that is effective in preventing slippage, so that even workers with muddy shoes do not slip. Is preferably applied to the floor surface.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In the following embodiment, a case where the present invention is applied to a conventional example of a cast-in-place pile method described with reference to FIGS. Therefore, although the construction procedure described with reference to FIG. 5 is provided, the rebar basket work scaffold is different as described below.

Referring to FIG. (A) First, the stand pipe 3 is press-fitted with the power jack 2 and the stand pipe 3 is built. A weight 5 is mounted on a weight table 4 around the power jack 2.
The stand pipe is buried, for example, about 10 m from the surface of the ground, and is sufficiently inserted to a stable impermeable layer below the groundwater level. (B) Next, the inside of the stand pipe 3 is excavated by the hammer grab 9. (C) Thereafter, a reverse excavator (not shown) is installed. At this time, a rotary table 11 for supporting the drilling pipe 10 is installed on the stand pipe 3 and fixed to a power jack (not shown) by a chain block (not shown). (D) Subsequently, reverse excavation is performed to a desired depth, and (e)
After the measurement and the slime treatment, the rebar basket-building work scaffolding 30 is set on the power jack.

FIG. 1 shows a front view of a scene of a rebar basket building operation according to an embodiment of the present invention. As shown in FIG.
A power jack 2 is installed, and a stand pipe 3 is built. Weight stand 4 provided beside base 1
Is mounted with a weight 5. As shown in FIG. 1, the power jack 2 includes a main cylinder 21 that expands and contracts in a vertical direction to press-fit the stand pipe 3, and a stand pipe 3.
The main tightening band 22 and the sub-tightening band 23 for tightening and holding the outer peripheral surface of the main tightening band, and the main tightening cylinder 24 and the sub-tightening cylinder 25 for driving the tightening bands, respectively.

The rebar basket-building work scaffold 30 is mainly composed of a base material 31. FIG. 2 shows a plan view of a base member 31 which is a main configuration of the rebar basket building work scaffold according to the embodiment of the present invention. FIG. 3 shows the base material 31, the stand pipe 3, and the main cylinder 2 of the power jack 2.
1 shows a half-body front view showing 1; As shown in FIG. 2, the base member 31 includes frame members 32, 3 such as steel square pipes.
It is a panel-shaped one in which expanded metal 35 is adhered as a floor material to a frame assembled by 3, 34. An octagon is formed in the center of the base member 31 by the four frame members 34 and the four portions of the frame member 33 as shown. An expanded metal 35 is attached to the outside of the octagon, but the expanded metal is not attached to the inside, and an octagonal hole 37 is provided. The stand pipe 3 is inserted into the hole 37. The hole 37 has a size that does not allow much for the outer diameter of the stand pipe 3, and is fitted into the outer periphery of the stand pipe 3 to be stable, and the displacement of the scaffold is suppressed.

As shown in FIG. 1, the reinforcing scaffolding work scaffold 30 has a handrail 41. As shown in FIGS. 2 and 3, a handrail mounting pipe 36 is attached to the frame member 32, and a pipe constituting the handrail 41 is inserted into and attached to the pipe 36. As shown in FIGS. 1, 2, and 3, the reinforcing scaffolding work scaffolding 30 is mounted on the power jack 2 so as to be supported by four main cylinders 21 located at equal intervals around the stand pipe 3.

As described above, the reinforcing scaffolding work scaffold 30 is provided.
(F) Reinforcing basket 7 is installed. When the reinforcing bar cage is built, the worker 6 carries out operations such as connecting the reinforcing bar basket 7 and the reinforcing bar basket 7 with the mechanical joint 8. that time,
The worker 6 can work using the rebar basket-building work scaffold 30 as a scaffold, thereby improving safety and workability. After the rebar basket has been built, (g) insertion of trummy pipe and slime treatment, (h) concrete placement, (i) withdrawal of stand pipe, and (j) earth covering and curing are sequentially performed.

In addition to the above configuration, the base material 31
In order to further stabilize the power jack, it is preferable to fit the base member 50 to the main cylinder 21 of the power jack 2 as shown in FIG. The heads of the main cylinders are fitted into the square frames formed at the four corners of the base member 50, respectively.
Thereby, the displacement of the base member 50 is further prevented.

In the above embodiment, the reverse circulation method is used. However, the present invention is not limited to this, and an all casing method, an earth drill method, or the like may be used.

[0020]

According to the first aspect of the present invention, a detachable scaffold is installed on the power jack after excavation of the pile hole and before the work of building the reinforcing cage, so that there is no trouble during excavation. There is an effect that a scaffold can be easily secured on a power jack, which has been unstable in the past, at the time of the work of building a reinforcing steel cage, and the stability and workability can be improved by stabilizing the scaffold.

According to the working scaffolding structure of the present invention, since a hole having a size into which a standpipe or the like can be inserted is provided, the scaffold can be quickly and easily formed around the standpipe or the like. And the scaffold can be quickly and easily removed. That is, according to the present invention, it is possible to form a work scaffold that is easy to attach and detach, and thus easy to install and remove, and that is excellent in stability, and has the effect of improving workability.

[Brief description of the drawings]

FIG. 1 is a front view of a reinforcing basket building work scene according to an embodiment of the present invention.

FIG. 2 is a plan view of a base member 31 according to the embodiment of the present invention.

FIG. 3 is a half-body front view showing a base material 31, a stand pipe 3, and a main cylinder 21 of a power jack 2 according to the embodiment of the present invention.

FIG. 4 is a plan view of a base member 50 according to the embodiment of the present invention.

FIG. 5 is a diagram showing a reverse circulation drill working sequence for explaining the working sequence in the embodiment of the present invention and the conventional example.

FIG. 6 is a front view of a conventional example of a rebar basket building work scene.

Claims (2)

[Claims] In a cast-in-place pile method in which a stand pipe or a casing is press-fitted with a power jack and a reinforcing rod cage is built in a pile hole, the pile pipe is excavated, and is attached to and detached from the power jack before the reinforcing steel cage building work. A cast-in-place pile method characterized by the installation of a possible reinforcing scaffolding work scaffold. 2. A hole which can be mounted on a power jack for press-fitting a standpipe or a casing in a cast-in-place pile method and has a size capable of inserting the standpipe or the casing. A scaffold for building a reinforced cage.