JP3913503B2 - Pile head treatment method for cast-in-place concrete piles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating a head of a cast-in-place concrete pile.
[0002]
[Prior art]
In order to build a cast-in-place concrete pile, after excavating a pile hole of a predetermined depth in the ground while preventing collapse of the hole wall with a stabilizing liquid such as bentonite liquid, a reinforcing bar is built in this pile hole, Next, the tremey pipe is inserted into the pile hole and the concrete is laid through the tremey pipe (hereinafter simply referred to as concrete), but the strength of the pile is reduced at the upper end of the cast concrete. Since impurities such as slime to be mixed are mixed, concrete is placed in advance up to the upper part of the top end of the planned pile to form a concrete pile on the pile head, and this pile is removed. The pile head is processed by doing.
[0003]
As such a pile head treatment method, conventionally, after hardening of the cast concrete, a method of scraping off and removing the extra portion of the concrete containing impurities such as slime, or an unhardened extra portion immediately after the concrete is placed The method of sucking and removing concrete with a vacuum hose is adopted.
[0004]
[Problems to be solved by the invention]
However, the former pile head processing method not only requires a large-scale apparatus and equipment, but also has a problem in that the environment is deteriorated by generating vibrations and large noises during the shaving operation. Therefore, the latter pile head treatment method that can eliminate the pile head scraping work by sucking and removing the concrete of the pile head extra portion immediately after placing the concrete and leveling the top of the pile is adopted. However, since it cannot be confirmed whether the concrete part containing impurities such as bentonite liquid and slime has been completely removed, after the concrete is hardened, the core as a specimen is removed from a part of the pile head. At present, quality is confirmed by performing tests such as compressive strength on the core.
[0005]
Therefore, it takes a lot of time and money to perform a lot of cast-in-place concrete from the extraction of the core to the test for compressive strength, etc., and it is impossible to move to the next work process until the test result is obtained. There was a point.
[0006]
The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to visually check the pile top by sucking and removing the piled-up portion of the pile head immediately after placing the concrete. It is in providing the pile head processing method of the cast-in-place concrete pile which can confirm whether an edge part is a concrete surface which has the normal intensity | strength which does not contain an impurity.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the pile head processing method for a cast-in-place concrete pile according to the present invention, as described in claim 1, puts concrete into a pile hole excavated in the ground to a predetermined depth, After pouring up to the lower vicinity, colored concrete is cast up to the upper part of the top end of the planned pile, and then the remaining colored concrete containing impurities such as slime above the top end of the planned pile. The top portion is removed by suction while confirming the colored shade, and then the top is leveled.
[0008]
[Action]
When a pile hole is excavated in a stable liquid such as bentonite liquid, part of the excavated earth and sand diffuses into the stable liquid and settles as a slime at the bottom of the hole. Since this slime has a lower specific gravity than the concrete to be placed, as the concrete is placed in the pile hole, it rises in a state of being deposited on the upper end surface of the concrete, and a part of it increases the strength of the pile together with the stabilizing liquid. It is mixed into the upper layer of the cast concrete as an impurity that deteriorates.
[0009]
On the other hand, if colored concrete is used as the final concrete to be placed in the pile hole, and this colored concrete is placed to the upper position beyond the top end surface of the planned pile, the excess of the colored concrete above the top end surface of the planned pile is left. Impurities such as slime are deposited on the raised portion, and a part thereof is mixed in the upper layer portion of the excess portion, and the color tone of the colored concrete, that is, the color tone is changed by the mixture.
[0010]
Therefore, if the extra portion of the uncured colored concrete is sucked and removed from the upper end side by a vacuum hose, the extra portion of the colored concrete is impure as the extra portion decreases and descends. The color changed from the mixed color to the color of the colored concrete before placing. When the upper end surface of the surplus part becomes the color of the colored concrete before placing by observing this, the vacuum hose Stop aspiration and removal. After that, the top end of the pile is leveled to create a pile having a predetermined quality and strength.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, specific embodiments of the present invention will be described with reference to the drawings. First, the construction procedure from the excavation of the pile hole to before the pile head processing of the present invention will be briefly described with reference to FIG. 1. This construction procedure is shown in FIG. B) After conducting a pre-drilling 1a in the ground as shown in Fig. 1 (b), the surface casing 2 is installed to prevent the collapse of the hole wall above the excavation hole, and then the hole to be excavated The pile hole 1 is excavated to a predetermined depth as shown in FIG. 1 (c) by the excavating machine 10 with the hole wall stabilizing liquid such as bentonite liquid filled therein. After excavation of the pile hole 1, primary processing of the slime settled on the bottom of the hole is performed, and then a reinforcing bar 3 is built in the pile hole 1 as shown in FIG.
[0012]
Next, as shown in FIG. 1 (e), the tremy tube 4 is suspended in the pile hole 1 until the lower end of the opening reaches the bottom surface of the pile hole 1 and subjected to secondary slime treatment. As shown in FIG. 1 (f), concrete 5 is placed in the pile hole 1 from the ground.
[0013]
The concrete 5 is placed in such a state that the lower end of the opening of the tremmy pipe 4 that supplies the concrete 5 into the pile hole 1 is always immersed in the concrete 5 that has been placed, and the concrete 5 is placed as the concrete 5 is raised. The immersion depth from the upper end surface 5a is pulled upward while maintaining a certain range (2 to 6 m). If the immersion depth of the tremmy pipe 4 from the upper end surface 5a of the concrete 5 is too shallow, it will cause material separation of the concrete 5, and if it is too deep, the outflow of the concrete 5 from the tremy pipe 4 cannot be stopped or the tremmy pipe 4 cannot be pulled up. Therefore, the concrete 5 is pulled up according to the placement of the concrete 5 while maintaining the depth of 2 to 6 m as described above.
[0014]
After placing concrete 5 in the pile hole 1 up to the lower vicinity of the top end surface of the planned pile head, as shown in FIG. 1 (G), the vacuum device (vacuum wheel) 11 passes through the vacuum hose 12. Suction and removal of slime and stabilizer on the cast concrete. Subsequently, it moves to the pile head processing method of this invention.
[0015]
In this pile head processing method, first, colored concrete 5A is prepared by coloring the same concrete as the cast concrete 5 described above, and this colored concrete 5A is used as the final cast concrete as shown in FIGS. Thus, it casts in the plan pile head part on the upper side from the concrete 5 cast to the top end face vicinity part of the plan pile head in the pile hole 1. The colored concrete 5A is placed until it reaches a predetermined height from the top end face 6 beyond the top end face 6 of the planned pile head, and an extra portion 5A ′ of the colored concrete 5A is provided above the top end face 6.
[0016]
The pigment used to color the concrete is a red (color number 130C) granule type inorganic pigment manufactured by Bayer, and this pigment is put together with concrete into the ready-mixed concrete mixer 13 at the pile construction site for about 5 minutes. The colored concrete 5A was prepared by rotating the drum at high speed and stirring. The amount of the pigment added to the concrete was set to 3% with respect to the unit cement amount so as to be within the influence range on the coloration and strength of the concrete.
[0017]
Impurities 7 such as slime, stabilizer, and components separated from concrete remain on the surplus portion 5A 'of the colored concrete 5A placed in the pile hole 1, and a part of the surplus portion is a surplus portion. Then, the portion where the impurities are mixed in the extra portion 5A ′ is sucked and removed by the vacuum hose 12 of the vacuum device 11 while it is uncured.
[0018]
First, as shown in FIG. 4, after pulling up the surface casing 2 to a position where the lower end has reached the top end surface of the planned pile head, and assembling a lifting and lowering trap and a working scaffold (not shown) in the surface casing 2, As shown in FIGS. 5 and 6, the vacuum hose 12 is inserted into the upper end of the pile hole 1 to remove and remove impurities remaining on the excess portion 5A ′, and the suction port of the vacuum hose 12 is colored. The surplus portion 5A ′ is sucked and removed while contacting or slightly immersing the upper end surface of the surplus portion 5A ′ of the concrete 5A.
[0019]
At this time, the worker enters the surface casing 2 by using the lifting trap and the scaffold, and confirms the top end level of the extra portion 5A 'of the colored concrete 5A which is sucked by the vacuum hose 12 and gradually descends. The change in color is visually observed, and when the color becomes the color of the colored concrete 5A at the time of placing, the suction and removal work of the extra portion 5A 'of the colored concrete 5A by the vacuum hose 12 is stopped. Thereafter, as shown in FIGS. 7 and 8, the top end surface 6 of the pile head 1A is leveled to finish the pile head.
[0020]
Next, as shown in FIG. 9, the crushed stone 8 is thrown into the upper pile hole 1 from the pile head 1A until reaching the upper end of the reinforcing bar 3 and the surface casing 2 is pulled out and removed, and the earth and sand are backfilled to the ground surface. To complete the work.
[0021]
【The invention's effect】
As described above, according to the pile head processing method of the cast-in-place concrete pile of the present invention, the concrete is placed in the pile hole excavated to a predetermined depth in the ground to the lower vicinity of the top end face of the planned pile, and then colored. Place concrete up to the upper part of the top end of the planned pile, and then check the colored tint of the extra portion of colored concrete mixed with impurities such as slime above the top end of the planned pile. Since the top of the colored concrete is smoothed after suction removal, if the extra portion of colored concrete is sucked and removed from the upper end side, the extra portion decreases and descends as the extra portion decreases. The color of the colored concrete at the height changes from the color that changes due to the mixing of impure content to the color of the colored concrete before placing, so coloring by observing this Impurities slime etc. Nkurito upper can reliably confirm whether or been removed.
[0022]
Therefore, as in the conventional pile head treatment method, it is confirmed that the built pile head has the specified quality and strength without having to core the part of the pile head and carrying out the compressive strength test. In addition, the pile construction work can be performed economically and efficiently in a short period of time.
[Brief description of the drawings]
FIG. 1 is a simplified longitudinal sectional view showing a construction procedure from excavation of a pile hole to before pile head processing,
FIG. 2 is a simplified vertical cross-sectional view of colored concrete being cast,
FIG. 3 is a longitudinal sectional view of the pile head part,
FIG. 4 is a simplified longitudinal sectional view showing a state where the reinforcing bar is pulled up to a predetermined height,
FIG. 5 is a simplified vertical cross-sectional view showing a state in which the upper layer portion of the surplus portion is sucked and removed,
FIG. 6 is a longitudinal sectional view of the pile head part,
FIG. 7 is a simplified longitudinal sectional view showing a state where the top end is leveled,
FIG. 8 is a longitudinal sectional view of the pile head part,
FIG. 9 is a simplified vertical cross-sectional view showing a state in which crushed stone is introduced.
[Explanation of symbols]
1 Pile hole
1A Pile head 4 Tremy tube 5 Concrete
5A colored concrete
5A 'Extra portion 6 Top face
12 Vacuum hose

Claims (1)

After placing concrete into the pile hole drilled to the ground at a predetermined depth to the lower part of the top end face of the planned pile, colored concrete is placed to the upper part of the top end face of the planned pile, and then planned. The excess of colored concrete mixed with impurities such as slime above the top end of the pile is removed by suction with a vacuum device while checking the colored color while uncured, and the colored concrete is colored when placed. A pile head treatment method for cast-in-place concrete piles, wherein the suction and removal work is stopped when the color becomes the same, and then the top edge is leveled.

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