JPH0336965B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is directed to the construction of cast-in-place concrete piles using the earth drill method and reparse circulation method, in which the pile head is filled with concrete after the pile is constructed. The present invention relates to a method for treating pile head concrete and its equipment, which facilitates pile head work and increases the concrete strength of the pile head.

[Prior art and its problems]

In general, cast-in-place concrete piles are constructed by drilling holes on the existing ground at predetermined locations and depths based on design drawings using stabilizing liquid, inserting reinforcing bar baskets, and pouring ready-mixed concrete into the piles. Since it is difficult to confirm the top of the head concrete and the concrete in the upper layer deteriorates due to lentance and sewage, we add about 1 meter of concrete to the specified length in advance, and after the root cutting work is completed, A construction method is used in which the concrete in the excess pile portion is removed to ensure the strength of the pile head concrete.

In the above construction method, the removal of the excess concrete is usually carried out using breakers, picks, etc., which not only has a negative effect on the quality of the reinforcing bars and concrete, but also causes damage during the scooping work. They generate pollution such as noise, vibration, and dust, causing deterioration of the surrounding environment.

In addition, recently, piles have been designed based on design guidelines for foundations against earthquake forces, and are designed with fixed pile heads, which increases the moment at the pile head and therefore increases the amount of reinforcing bars. As the spacing between the piles becomes narrower, the ready-mixed concrete does not bulge around the outer periphery of the reinforcing bar cage when the ready-mixed concrete is added, and cement paste collects near the pile head, causing problems such as a significant deterioration in the quality of the pile-head concrete.

For this reason, recently, a reflector plate is attached to a pipe with a nozzle at the tip for an appropriate length of time, and compressed air is sent through the pipe by inserting it into the excess concrete and injecting the air into the reflector plate.
The air diffuses upward and stirs the concrete,
One method is to push the cement particles up and separate them into gravel, sand, and cement paste.

When using the above method, the normal earth drill method,
In the reverse method, the stabilizing liquid used for drilling
It is filled up to the GL, and after inserting and fixing a reflector plate according to the height of the top of the pile head, injecting air, the air diffuses upward and stirs the concrete, pushing the cement paste into the stabilizing liquid and releasing it into the atmosphere. emanates from. Because of this repetition, convection occurs in the stabilizing liquid, resulting in localized deep erosion of the pile cap height, making it difficult to uniformly secure the boundary line of the pile cap height. There are also problems such as having to scrape off the concrete from the eroded areas at a later date.

The purpose of the present invention is to eliminate such drawbacks by press-inserting a cover plate into the height of the top of the concrete pile cap and bringing it into close contact, increasing the compressive strength of the concrete pile cap, and separating only the excess concrete portion. This makes the subsequent concrete scooping work easier.

[Means for solving problems]

A suitable number of hollow pipes with nozzles at their tips are fixed to a circular bottom plate whose diameter is slightly smaller than the inner diameter of the reinforcing bar cage, at a predetermined interval and an appropriate distance, and the upper end of the hollow pipe is made into a ring pipe. In order to accurately guide the insertion device to the center of the reinforcing bar cage, several guide pipes are attached and detached in advance to the upper end of the reinforcing bar cage. The present invention comprises a guide device for accurately suspending the concrete into the excess concrete, a circular bottom plate at the lower end of the insertion device, and a cover plate having approximately the same shape as the circular bottom plate on the lower surface of the bottom plate. After attaching the cover plate in such a way that it can be easily removed from the circular bottom plate, the insertion device is lowered into the pile hole, and while the insertion device is vibrated with a vibrator, it is pressed into the excess concrete. After inserting the device and pressing it against the top of the concrete pile, blowing air into the excess concrete and stirring the excess concrete and stabilizing liquid, the insertion device is recovered and only the cover plate is placed in place. Coarse aggregate, fine aggregate, and laance are separated and deposited on a fixed lid plate by utilizing the difference in their specific gravity.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

After drilling a pile hole B with a desired diameter and depth in the ground A using a ground drill method, reverse circulation method, etc. with a stabilizing liquid 4 and a surface casing 6, the main reinforcement 2b is drilled as shown in Fig. 1. Anchor part 2
A reinforcing bar basket 2 bound with hoop bars 3 is built into the pile hole B. Then, guide pipes are removably inserted into several anchor portions 2a of the main reinforcement 2b, and the upper and lower ends of the guide pipes are connected by a ring frame 8, so that a guide device 7a is integrated with the reinforcing bar cage 2. Pile hole B is built at the specified height,
Next, concrete 1 is cast into the pile hole B using a tremie or the like, and a height h of a surplus portion (about 1 m) that is slightly higher than the planned height C of the pile is set in the pile hole B.
Additional concrete 5 is also placed at the same time.

Next, when the concrete 1 and the extra concrete 5 are in an unhardened state, an insertion device 9 is inserted as shown in FIG.
is suspended from the center of the reinforcing bar basket 2 by the guide device 7a and inserted into the extra concrete 5.

The insertion device 9 is inserted into a circular bottom plate 10 having a slightly smaller diameter than the inner diameter of the reinforcing bar cage 2, as shown in FIG.
A suitable number of hollow pipes 11 each having a nozzle 11a at the tip are arranged at suitable intervals and the pipe fixing leg 1
2, and the upper ends of the hollow pipes 11 are connected to the ring pipes 13, respectively, and the insertion device 9 is vertically divided into three frames: a first frame 9a, a second frame 9b, and a third frame 9c. As shown in FIG. 8, these three frames each have a hollow pipe 11 fixed thereto by a ring frame 14 and a connecting brace 15.

The first frame 9a, the second frame 9b, and the third frame 9c are vertically connected to the hollow pipes 11 of each frame by sockets 16, and the second frame 9b can be adjusted according to the required length. As shown in FIG. 7, an air supply pipe 13a having the same diameter as the ring pipe 13 is connected to the ring pipe 13 disposed at the upper end of the insertion device 9 so that air can also be supplied to the central hollow pipe 11. They are connected and fixed by pipe braces 17.

A circular bottom plate 1 provided at the tip (lower end) of the insertion device 9
0, as shown in FIG. 6, a suitable number of entrance and exit holes 18 are bored in a steel plate having a slightly smaller diameter than the inner diameter of the reinforcing bar cage 2, so that the insertion and withdrawal of the insertion device 9 can be easily performed. Further, a vibrator 21 is installed at the upper end of the connecting place 15.

A cover plate 19 attached to the lower surface of the circular bottom plate 10
As shown in FIG. 9, it is manufactured using plywood or the like, and its outer periphery is approximately the same shape as the circular bottom plate 10,
The same number of concrete outlet holes 20 are drilled at the same position as the entrance hole 18, and the width of the hole is equal to that of the entrance hole 1.
Each piece is made slightly smaller than 8, and this is made into circular bottom plate 1.
0 using double-sided tape or the like so that it can be easily removed.

Using the apparatus configured as described above, the construction method will be explained next.

A cover plate 1 is attached to the bottom surface of the circular bottom plate 10 of the insertion device 9.
The insertion device 9 is made removable by pasting or using other methods, and the insertion device 9 is lifted by a crane, and the guide device 7 is placed in the center of the reinforcing bar cage 2 built in the pile hole B.
It is lowered using a and inserted into the extra concrete 5 that has been placed previously. This is done by using the insertion device's own weight or other external force to push it into the excess concrete. At this time, if the vibrator 21 is driven and the circular bottom plate 10 is press-fitted through the hollow pipe 11 while applying vibration, a part of the excess concrete is transferred to the cover plate 19 through the concrete extrusion hole 20 of the cover plate 19. The cover plate 19 is press-fitted while protruding upward, and is inserted to a predetermined concrete top height c position. At this time, the cover plate 19 is in a state where the concrete is pressed against the concrete at a high position at the top of the concrete.
At this point, the drive of the vibrator 21 is stopped, and another installed compressor is then driven to send compressed air into the ring pipe 13 through the air hose 22. As a result, the compressed air passes through each hollow pipe 11, is injected into the excess concrete from the nozzle 11a, collides with the circular bottom plate 10, is reflected and diffused, and rises while stirring the excess concrete 5, into the stabilizing liquid 4. and emit into the atmosphere. By supplying compressed air for a predetermined period of time, for example, 2 to 3 minutes, the excess concrete 5 and the stabilizing liquid 4 are sufficiently stirred and mixed, and then the supply of compressed air is stopped,
The insertion device 9 is lifted up by a crane and removed from the excess concrete. At that time, the circular bottom plate 10
The cover plate 19 attached to the bottom surface has a structure in which the concrete outlet hole 20 made in the cover plate 19 is smaller than the entrance hole 18 made in the circular bottom plate 10, so there is no concrete aggregate in that part. As it accumulates, it easily separates from the circular bottom plate 10 due to the vacuum phenomenon caused by the pressure bond between the lower surface of the cover plate 19 and the concrete 1, and is left at the concrete top height C position. When recovering this insertion device, the circular bottom plate 10
The insertion device 9 is pulled up and recovered while the concrete aggregate flows downward through the inlet/outlet hole 18. Remaining concrete 5 is separated into coarse aggregate 5a, fine aggregate 5b, and letance 5c by blowing compressed air, and the cover plate 1 is sequentially separated by the weight difference.
9 is deposited by sedimentation.

Further, the guide device 7a is pulled up and recovered by a crane after the insertion device 9 has been press-inserted, immediately before air is supplied, or immediately after the insertion device 9 is pulled up.

〔Effect of the invention〕

According to the present invention, a suitable number of hollow pipes each having a nozzle at the tip thereof are fixed at a predetermined interval and an appropriate distance to a circular bottom plate whose diameter is slightly smaller than the inner diameter of the reinforcing bar cage. There is an insertion device whose upper end is connected to a ring pipe and equipped with a vibrator, and several guide pipes are attached and detached from the upper end of the reinforcing bar cage in advance in order to accurately guide the insertion device to the center of the reinforcing bar cage. A guide device that can be freely placed and suspended accurately into excess concrete, a circular bottom plate at the lower end of the insertion device, and a cover plate having approximately the same shape as the circular bottom plate on the lower surface of the bottom plate. It consists of
After attaching this cover plate to the circular bottom plate in such a way that it can be easily removed, the insertion device is lowered into the pile hole, and while the insertion device is vibrated with a vibrator, it is inserted into the excess concrete. Pressure insert,
The pile head is crimped to the top of the concrete, air is blown into the excess concrete, the excess concrete and stabilizing liquid are stirred, and then the insertion device is recovered and only the cover plate is placed in place, thereby removing the coarse aggregate in the excess concrete. , fine aggregate, and letance are separated and deposited on a fixed lid plate by utilizing their specific gravity difference, so the insertion device can be adjusted to the desired length using a guide device. It can be inserted accurately into the center of the rebar cage through the
This insertion device is equipped with a vibrator, which applies vibrations to the circular bottom plate while compressing the excess concrete with the cover plate and crimping it to a predetermined depth, so that the pile head concrete is attached to the outer periphery of the reinforcing bar cage. The concrete rises uniformly, becomes compacted and hardens, increasing the compressive strength of the pile head concrete.
Moreover, the cover plate prevents adverse effects such as erosion caused by air injection, and the separated concrete aggregate is deposited on the cover plate and is completely separated by the cover plate, and the concrete at the pile head is completely separated by the cover plate. It is possible to ensure the strength of the coarse aggregate in the extra concrete,
Since the fine aggregate and letens are separated and deposited, it has the advantage of greatly contributing to the efficiency of subsequent pile cap processing work.

[Brief explanation of the drawing]

Figure 1 is an installation diagram of the pile hole and guide device, Figure 2 is a hanging diagram of the insertion device with a cover plate attached, Figure 3 is a diagram of the insertion device's pressure insertion and air injection status, and Figure 4 is the insertion Concrete separation status diagram after equipment recovery, No. 5
The figure is a structural diagram of the insertion device, Figure 6 is a plan view of the circular bottom plate, Figure 7 is a cross-sectional view taken along line A-A in Figure 6, Figure 8 is a cross-sectional view taken along line B-B in Figure 6, and Figure 9. 10 is a plan view of the cover plate, and FIG. 10 is a plan view of the pile head immediately after pressure insertion by the insertion device. A is the ground height, B is the pile hole, C is the planned concrete height, 1 is the concrete frame, 2 is the reinforcing bar cage, 2a is the main reinforcement anchor part, 2b is the main reinforcement, 3 is the hoop reinforcement,
4 is stabilizing liquid (muddy water), 5 is extra concrete, 6
is a surface layer casing, 7 is a guide pipe, 7a is a guide device, 8 is a guide brace, 9 is an insertion device,
10 is a circular bottom plate, 11 is a hollow pipe, 11a is a nozzle, 12 is a pipe fixing leg, 13 is a ring pipe, 13a is a connecting pipe, 14 is a ring frame, 15 is a connecting brace, 16 is a socket, 17
18 is a pipe brace, 18 is a concrete inlet/outlet hole, 19 is a cover plate, 20 is a concrete outlet hole, 21 is a vibrator, 22 is an air hose, and 23 is a valve.

Claims (1)

[Scope of Claims] 1. An insertion device having a cover plate on the lower surface, which is placed at the top of the pile, is press-inserted into a predetermined position while applying vibration, and then Compressed air is injected into the excess concrete from the lower part of the insertion device to agitate the excess concrete and the stabilizing liquid, and the insertion device is recovered by leaving the cover plate in a predetermined position. A pile head concrete treatment method for cast-in-place piles, characterized in that coarse aggregate, fine aggregate, and laitance of piled concrete are separated and settled and deposited by utilizing their specific gravity differences. 2 A suitable number of hollow pipes with nozzles at their tips are fixed at a predetermined interval and an appropriate gap to a circular bottom plate whose diameter is slightly smaller than the inner diameter of the reinforcing bar cage, and the upper end of the hollow pipe is attached to a ring pipe. The insertion device is connected to each of the reinforcing bar cages and integrated into one body, and is equipped with a vibrator. A means for accurately suspending into the excess concrete, and a cover plate having approximately the same shape as the circular bottom plate on the lower surface of the circular bottom plate at the lower end of the insertion device, so as to be easily detachable from the circular bottom plate. A pile head concrete treatment device for cast-in-place piles, characterized in that the piles are pasted, the insertion device is lowered, the pile is press-inserted into the extra concrete, the piles are brought into close contact with a predetermined planned height, and the piles are left as they are. . 3 The shape of the circular bottom plate at the lower end of the insertion device is made slightly smaller than the inner diameter of the reinforcing bar cage, and multiple concrete entrance and exit holes are provided so that concrete overflows when the insertion device is inserted, and separated concrete flows when it is pulled out. 3. A pile cap concrete treatment device for a cast-in-place pile according to claim 2, which allows aggregate to flow out to facilitate insertion and recovery of an insertion device. 4. The cover plate to be attached to the lower surface of the circular bottom plate has approximately the same shape as the circular bottom plate, and has the same number and location at the same location as the numerous concrete entrance holes drilled in the circular bottom plate, and has a cross section of each opening hole. 3. A pile head concrete processing device for a cast-in-place pile as claimed in claim 2, wherein a concrete protrusion hole with a reduced area is provided to increase the compressive strength of the concrete and to facilitate the removal of the circular bottom plate.