JPS63103121A - Field piling work - Google Patents

Abstract

PURPOSE:To prevent the degradation of pile pit and the embrittlement of pile by reducing the amount of water to be drained in excavated soil and also by strengthening the wall of the pit by a method in which when the pile pit is excavated, the excavated soil is pressed on the wall of the pit and the slime is removed. CONSTITUTION:Drums 4 and 4a having much the same outside diameter as the inside diameter of a pile pit 2 to be excavated are fixed to a hollow shaft 3, and a stirring blade 5 is radially and projectionally provided in a vertically staggering form between the drums 4 and 4a. The pile pit 2 is excavated by an earth auger 1 having an auger blade 6 of a slightly smaller outside than the pit 2 on its lower end and also having an auxiliary spiral 7 to carry excavated soil by the blade 6 to slightly upward direction. After the excavation is made to a preset depth, slime and soil on the bottom of the pit 2 are removed as much as possible by pulling up the auger 1 having the blade 6 with soil. A reinforcing bar cage is set in the pit 2 and concrete is placed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for constructing reinforced concrete piles at a foundation construction site, and is used in the field of foundation pile construction.

(Prior art) Regarding the conventional foundation pile installation, there is a method (Japanese Patent Publication No. 58-4128) of excavating a pile hole and burying a ready-made concrete pile in the hole while strengthening the wall of the hole where the pile is planned to be installed. Are known.

Next, to construct a concrete pile on site, the excavated soil is removed using a screw auger, bentonite is poured into the pile hole, a reinforcing bar cage is inserted, and then the bentonite and concrete are replaced with the concrete pile on site. Construction methods are also known.

(Problems to be Solved by the Invention) The installation method of ready-made concrete piles is widely used in various places because it generates relatively little noise and requires relatively little treatment such as evacuation.

However, although ready-made piles have high strength and reliability, they must be transported from the production factory to the construction site.
In order to withstand the bending stress that is applied to the piles during transportation, it is not only necessary to reinforce the foundation piles beyond the stress that is originally required (by inserting a large amount of reinforcing bars or tensile steel), but also to strengthen them due to weight and other factors. Due to restrictions, it is long (e.g. 20m)
(above), there was a point H while thick piles (for example, around 1 m in diameter) could not be used.

In addition, conventional on-site construction piles require the removal of all the earth, and there is a problem in that the hole wall is easily damaged when the pile hole is excavated.

(Means for Solving the Problems) However, the present invention significantly reduces the amount of excavated soil by pressurizing and kneading the excavated soil onto the walls of the pit during excavation, and at the same time, the amount of excavated soil is significantly reduced. Succeed in preventing Kuiroku's collapse by strengthening it.

In addition, by removing as much slime that has accumulated near the bottom of the pile hole as possible, weakening of the bottom of the concrete pile can be prevented, resulting in a foundation pile with high strength and reliability.
The installation was successful.

That is, this invention involves digging a hole to a predetermined depth at a site where concrete piles are to be installed, strengthening the hole wall, removing as much slime as possible from the bottom of the hole, and then inserting a reinforcing bar cage. After that, concrete is filled into the pile hole and the pile is constructed on site.

In the above, the hole walls are reinforced by, for example, crushing the excavated soil and turning it into mud, and kneading this into the hole walls using a rotating drum or the like.

By kneading a considerable portion of the excavated soil, the amount of soil removed is reduced and the walls of the pit are reinforced.

In addition, slime can be removed by using a spiral blade attached to the tip of the earth auger (excavated soil will stick to the spiral blade, so just pull it up), or by suctioning it using a discharge pipe. a.

The above-mentioned reinforcing bar cage is constructed by placing reinforcing bars at equal intervals between upper and lower end plates, and having spiral bars or hoop bars surrounding the outer periphery of the reinforcing bars, or having no upper and lower end plates, or having an upper end plate. There are reinforcing bars arranged at equal rgjrWJ between the lower m-tube collar and a reinforcing cage with screw bars or hoop bars fixed around the reinforcing bars, or a concrete tube connected above or below.

According to the invention of the concrete pile built on site, by removing the slime at the bottom of the pile as described in U, when excavating a pile hole, the excavated soil is crushed and kneaded into the hole wall, so the hole wall is It can be reinforced and prevented from collapsing. Since the slime at the bottom of the pile is removed, the strength of the entire length of the concrete pile can be maintained evenly.

(Embodiment 1) Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

First, using the earth auger 1, a hole 2 is excavated at the site where the concrete pile is to be constructed. In the earth auger 1 in this case, drums 4.4a having an outer diameter approximately equal to the inner diameter of the hole 2 to be drilled are fixed at appropriate positions above and below the hollow shaft 3, and stirring blades 5.5a are installed between each drum. are protruded radially and vertically in a staggered manner, and an auger blade 6 and an auxiliary spiral 7 are sequentially provided at the lower end. The auger blade 6 is used for digging the hole 2, and its outer diameter is slightly smaller than the diameter of the hole 2.
The auxiliary spiral is a screw conveyor that transports the soil excavated by the auger blade 6 upward by a certain distance (for example, 50 G to Lm).

The hollow shaft 3 is capable of withstanding the rotational force of the earth auger 1, and allows pressurized water or cement milk to flow inside.

In the above, when the earth auger 1, which is supported upright on the tower of the excavator, is rotated, the planned ground is successively excavated by the auger blade 6, and as the auger blade 6 descends, the auger 6 is excavated. In this case, the excavated soil is carried upward by the auxiliary spiral 7, is then crushed by the stirring blades 5.5, and is kneaded under pressure against the borehole wall as the drum 4.4a rotates. It depends on the quality of the excavated soil, but the excavated soil is kneaded with a fairly high yield. When excavating with the auger blade 6, if an appropriate amount of water is injected from the lower end of the hollow shaft 3, the auger blade 6 can dig smoothly, and the excavated soil can be turned into mud and kneaded by the drum 4.4a. can be made even easier. Furthermore, if the gushing water accumulates in the hole 2, the excess water will turn into muddy water and overflow, allowing some automatic soil removal. Once the earth has been excavated to the planned depth as described above, the water from the earth auger 1 is spouted out and the soil is pulled up with the soil stuck to the auger blade. In this way, the upper excavated soil and slime are pulled up from the auxiliary spiral 7 and subsequently discharged to the outside of the pile hole 2. In the above, cement milk or bentonite is used instead of water,
Alternatively, it is preferable to eject a composite of these replacement materials from a hollow shaft, since the area below the auger blade will not be vacuumed.

Next, several reinforcing bars 10.10 are fixed to the upper and lower end plates 8.9 at equal intervals, and a screw bar 12 is fixed to the reinforcing bars 12 around the periphery of the reinforcing bars 11.
into the pile hole 2, and then insert the transfer pipe 13 into the inside of the reinforcing bar basket 11 while pouring out the fresh concrete transfer pipe 13. If the transfer pipe 13 does not reach the bottom of the pile hole, the transfer pipe 13 is poured out. Transfer pipe 1 while taking out fresh concrete from pipe 13.
3, and fill the hole with ready-mixed concrete.

In this way, a concrete pile 14 in which iron Ba1l is buried is created in the pile hole 2.

(Example 2) Next, in the embodiment shown in FIGS. 4 and 5, a steel pipe 16 is connected to the lower end of the reinforcing bar cage 15 in place of the reinforcing bar cage 11 of the first embodiment, thereby forming a composite cage 17. , all other points are the same as in Example 1. 6 In addition, Fig. 4 shows the case where the copper pipe 16 has reached the final stage, and Fig. 5 shows the case where the lower end of the steel pipe 16 has been lifted slightly from the final stage. This is an example.

(Embodiment 3) The embodiments shown in FIGS. 6 to 8 are examples in which the bottom of the hole is enlarged to a larger diameter than other parts.

FIG. 6 shows an example in which the lower end of the reinforcing bar basket 11 is slightly raised above the bottom surface of the expanded bottom part 18, FIG. 7 shows an example in which the lower end of the reinforcing bar cage 11 reaches the bottom surface of the expanded bottom part 18, and FIG. 8 This is an example in which a composite basket 17 is used.

Among the above embodiments, in the case where the composite basket 17 is used, the strength of the tip of the concrete pile can be increased by reinforcing the steel pipe 16.

(Example 4) In the example shown in Fig. 9, concrete I/tube 20
The other points are as follows.

(Effects of the Invention) According to this invention, since the excavated soil is consolidated and reinforced to the wall of the pile hole, there is no risk of collapse after the pile hole is excavated and before concrete is poured, and the amount of excavated soil discharged is also small. It has a soothing effect. Furthermore, since the slime at the bottom of the pile is removed as much as possible, it has the effect of preventing a decrease in the strength of concrete piles caused by slime.

[Brief explanation of the drawing]

The figures show examples of the present invention. Figure 1 is a cross-sectional view when drilling a hole, Figure 2 is a cross-sectional view when a reinforcing cage is inserted and concrete milk is poured, and Figure 3 is a cross-sectional view when concrete milk is poured. 4 is a cross-sectional view of an embodiment using a composite cage; FIG. 5 is a sectional view of an embodiment in which the lower end of the composite cage is raised slightly above the bottom of the stake; FIG. 6 7 is a sectional view of an embodiment with an expanded bottom, in which a reinforcing bar cage is in contact with the pile bottom, and FIG. 8 is a sectional view of an embodiment using a composite cage. Figure 9 is a cross-sectional view of an example of a composite base using a concrete pipe.

Claims (1)

[Claims] 1. A hole of a specified depth is dug at the site where concrete piles are planned to be installed, while the walls of the hole are strengthened, and after removing as much slime as possible that has accumulated at the bottom of the hole, a reinforced cage is installed. A method for constructing piles on site 2, characterized by inserting concrete into the pile hole and then filling the hole with concrete.The patent claims that the hole wall is strengthened by crushing the excavated soil and kneading it into mud under pressure. On-site pile construction method according to claim 1 3 The slime is removed by discharging the earth auger with mud attached to the tip of the earth auger. 4 The on-site pile construction method according to claim 1, in which the slime is removed by inserting a sludge pipe and removing it by suction. A screw bar is fixed around the outer circumference of the reinforcing bar, upper and lower end plates are provided at the end of the reinforcing bar,
Or the method for constructing piles on site according to claim 1 without end plates 6 The reinforcing bar cage has reinforcing bars arranged at equal intervals between the upper end plate and the lower steel pipe collar, and the reinforcing bars are provided with screw bars. The on-site pile construction method 7 according to claim 1, in which the reinforcing bar cage is fixed around the circumference of the reinforcing bars.