JPS6250515A - Treatment work for head of in-site concrete pile - Google Patents

Abstract

PURPOSE:To make the treatment work of pile head easier by a method in which a bucket is attached to the inside pile head portion of a reinforcing bar cage, extra-banking concrete is poured from the hole of the bottom plate of the bucket into the bucket, and when the concrete becomes semi-hardened, the bucket is lifted up to discharge the concrete. CONSTITUTION:A reinforcing bar cage 2 is erected in an excavated pit 1, and a bucket 3 having a lubricant film of resin emulsion on its inner and outer faces is installed on the pile head 4. A tremie tube 7 is inserted through the hole 6 of the bottom plate 5 of the bucket 3 and concrete 8 is placed through the tube 7. When the top of the concrete 8 rises up to the bottom plate 5 of the bucket 3, the concrete 8 flows through the gap between the hole 6 and the tube 7 into the bucket 3 and partly goes up the surrounding of the cage 2, where the concrete 8 is placed up to the level of about 70cm or more from the pile head 4. When the concrete 8 becomes semi-hardened, the bucket 3 is lifted up to discharge the extra-banking concrete 8' to the ground's surface.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for treating the pile head of a cast-in-place concrete pile by easily removing excess reconcrete from the pile head.

Conventional technology and its problems Cast-in-place concrete piles are generally constructed prior to root cutting work, but the designed pile head is located deep underground, and there are cases where concrete is cast in muddy water. In many cases, it is difficult to confirm the pile cap, and the concrete at the pile cap deteriorates due to laitance, slime, and muddy water. After cutting the roots, a method was used to remove the roots using a breaker or chipper.

However, by this point, the concrete had completely hardened, which not only increased construction time and costs, but also caused many problems such as noise, vibration, and dust generation.

Therefore, in recent years, various improved construction methods have been adopted for the purpose of solving these problems. An improved method is to remove excess kelp in an uncured state using a vacuum pump nut (JP-A-Shoj (/-/J)).
Jt/θ Publication) and a method of separating and stacking the bed using an air lift by injecting compressed air (Special Publication Sho J1-Jul
(Ir Publication).

This must be done immediately after concrete pouring.

Problems include the need for large-scale equipment and machinery other than those for piling work, as the work hours are extended, including night work.

Separately, there is a method of excavating and removing forced concrete when it is semi-hardened using a bucket attached to the tip of a bar (Japanese Unexamined Patent Publication No. 5S-IORJIJ).
Although there is.

Since it is necessary to carry out the work within 72 hours after concrete pouring, the work hours may be extended and the work may be late at night. Furthermore, in the case of a cast-in-place pile construction method that does not use a kelly bar or a bucket whose bottom can be opened and closed, it is necessary to separately install these devices and machines, and the lack of versatility causes problems in economic efficiency.

In order to solve the problem, the present invention aims at semi-hardening the surplus concrete,
This method uses a bucket to remove the slime, etc. contained in the poured concrete, which is removed by installing a bucket on the top of the reinforcing bar cage and allowing the slime, etc. contained in the poured concrete to enter the bucket through the holes in the bottom plate of the bucket. At the early stage when the material has hardened to the point where it cannot be removed from the bottom hole of the bucket,
Pull out the bucket, lift it to the ground, and remove the excess concrete inside. In order to make this work easier with less force, the bucket has a tapered shape with a smaller diameter at the bottom due to the effect of the synthetic resin emulsion electrodeposited coating and other lubricating coatings formed on the inner and outer steel plate surfaces of the bucket. By doing so, it is possible to pull out the concrete even if the concrete hardens slightly.

In addition, when collecting excess concrete I+-t into the bucket, four people should remove the top laitance etc.
1) flows naturally through the hole in the bottom plate of the bucket and the tremie tube for sinking.

Example The present invention will be explained based on an example shown in the drawing.

Figure 1 is a longitudinal cross-sectional view of the woodwork method at the end of concrete pouring. An excavation hole with a predetermined diameter and depth is formed in the ground using a cast-in-place pile excavator, and the reinforcing bar J assembled on the ground is erected.

Next, the bucket J, whose inner and outer surfaces have been coated with a lubricating film by electrodepositing a resin emulsion, is installed on the designed pile cap 4, and a hole with a diameter of about JOW, which served as the bottom of the bucket, is made 1. Then, the tremie pipe 7 is inserted and a concrete groove is poured. When the top of the concrete rises and reaches the bottom plate j of the bucket, the concrete at the top mixed with laitance passes between the hole g and the tremie pipe 7 and reaches the bucket J.
Concrete will naturally flow into the interior of the pile, and some of it will rise around the reinforcing bar, and concrete will be poured to a height of approximately 70 cm or more from the designed pile cap.

FIG. 2 is a longitudinal cross-sectional view of the bucket 3 when it is pulled out and hoisted above the ground. When the concrete becomes semi-hardened fn, the bucket) J is pulled out and lifted up, turned over on the ground, and the excess concrete t' is discharged. Reinforcing bar fi at pile head
Any excess concrete remaining around the roots will be removed at the point where it has hardened at the end of the root cutting.

Bucket) The lubricating coating on the inside and outside surfaces of J is made of excess concrete)
C, C, C and concrete T will adhere to it, so if bucket J is used repeatedly, electrodeposition should be applied each time. This electrodeposition coating is carried out in a conventional manner.

No. Jq is the vertical cross-section at the time of concrete placement in the case of a large diameter (2 ml or more in diameter) cast-in-place pile. The diameter of the tremie tube 7 to be used is also a little thicker, so the bottom surface of the bucket) J
The diameter r of the hole g used for this purpose will also vary by toes, and if the diameter of the bucket J is taken as the diameter of the bucket J, then λ-r will be more than j0tx, and there is a risk that concrete mixed with laitance or stime will get caught under the bottom plate j. As shown in the figure, make the bucket J into a shape (truncated conical shape) with the center raised from the outside part so that the conc I + -) t smoothly flows into the inside of the bucket J in the direction of the arrow. In this case, the amount of excess concrete l' that is in a hardened state after the root cutting work increases.

The present invention is applied to pile diameter/, I m , bucket) diameter of J
t-y, tm, diameter of hole t in e-plane 5 y −j Ocs.

This was carried out at a height of 7σ of excess concrete.

used one with a horizontal bottom surface j as shown in FIG.

According to the results of a prayer investigation of the concrete of the designed pile cap l at the bottom of the bottom j after pulling out the bucket) J, there was no evidence of any entanglement of laitance or slime, and it was found that the concrete t was connected to the hole t of the bottom plate j. It was confirmed that the concrete flowed smoothly between the tremie pipes 7 and into the bucket 3, and that there was no problem with the quality of the concrete of the designed pile head.

The force required to pull out the bucket J was about 10 tons in the case of the example in which about 1 hour had elapsed after concrete pouring. This force is 0.7 ton for g1 of bucket J, and @t-ZJt for reconc.
on, the tensile resistance a0ton of the concrete with a diameter j0c1m at the hole 4 part of the bucket bottom plate (assuming the tensile strength after the impact time is /4/-), and the outer surface of the bucket J and the concrete t. Adhesion resistance with 〃, jt
on (adhesion strength when applying lubricant coating is o, /
b/-), the total 5' and jton almost matched. Therefore: +13-) If the bucket 3 is pulled out within 2 days after the inspection, it can be pulled out using a pile-driving machine. The work of removing surplus concrete I+ -) j' and dividing it into small pieces can also be done with a universal excavator for pile construction.

The work can be carried out at any time in a short period of time using pile construction machines and workers, resulting in excellent cost savings.

Effects of the Invention According to the present invention, when a bucket with a small diameter bottom is inserted into the top of a reinforcing bar cage and inside the cage, laitance and slime are removed between the bucket bottom hole and the tremie pipe. Since the bucket is inserted into the bucket in advance and pulled out when the concrete is semi-hardened, the need for excess concrete is greatly reduced.

In other words, the excess concrete around the reinforcing steel cage that has hardened after root cutting work has been reduced to 30 to <104 (7) (1 is the total excess concrete I+-), and the concrete that has hardened after root cutting has been reduced to 30 to <104. construction period is 20~JO%.
It was shortened to .

Since there is no need to bend or reposition the main reinforcement of the pile, it is also superior in terms of the quality of concrete and reinforcing steel.

Furthermore, the reduction of the excess concrete II-t characteristic can save labor, and has the advantage of shortening the construction period and reducing the problems of noise, vibration, and powder ratio by 1.

4 The Iy2I11 late stage 1g1 to @3 diagrams are detailed explanatory diagrams of the present invention. Figure 1 is a vertical cross-sectional view at the end of concrete pouring, and @Konari is a vertical cross-section of the barking state with the bucket pulled out. Fig. JI'3] is an explanatory diagram in the case of a large-diameter cast-in-place concrete pile.

/ is the excavation hole, C is the iron fJ cage, J is the bucket, 4 is the pile head, j is the bottom plate of the bucket, O is the hole, 7 is the tremie pipe, and r is the concrete.

〆, f is excess concrete.

Figure 1 Figure 3

Claims (2)

[Claims] (1) When constructing cast-in-place concrete piles, a steel bucket with a hole in the bottom plate is installed inside the reinforcing bar cage at a predetermined height of the pile head, and when concrete is poured, extra concrete is poured into the bottom plate. It flows into the bucket through the hole. A pile cap processing method for cast-in-place concrete piles, which is characterized in that when the concrete is in a semi-hardened state, the bucket is pulled out from the pile cap, lifted to the ground, and removed from the bucket. (2) In order to make it easier to pull out the bucket and remove concrete from the bucket, the diameter of the top of the bucket is slightly larger than that of the bottom, and the surfaces of the steel plates inside and outside the bucket are coated with lubrication, such as an electrodeposited film of synthetic resin emulsion. A method for treating the head of a cast-in-place concrete pile according to claim 1, which comprises forming a coating.