JPS5898525A - Driving method for cast-in-place concrete pile and device thereof - Google Patents

Abstract

PURPOSE:To improve a support power of a concrete pile, by a method wherein an unbrella-shaped member having a nozzle is mounted to a forward end of a tremie pipe, and slime is floated with a jet from a nozzle to remove the slime by means of an air lift action. CONSTITUTION:A reinforced cage K is suspended into a hole excavated by a mud water method to install it therein. Water is jetted through a nozzle 8a of a jet body 8 around a forward end of an unbrella-shaped member 4 at a forward end of a tremie pipe 2, and this causes floating of slime S settling down at the bottom of the hole. Simultaneously, air is jetted into the tremie pipe 2 through an air pipe 10, and the slime S is discharged to the outside of the hole by an air lift action. After the slime S on the hole bottom is removed, concrete is deposited by the use of the tremie pipe 2.

Description

[Detailed Description of the Invention] The present invention relates to a method for driving concrete piles and an apparatus therefor. An umbrella-shaped member is provided at the tip of the tremie tube, and a quarter-jet outlet is provided near the tip of the umbrella-shaped member and an air-jet outlet is provided above it to eliminate slime.
This article relates to a method for driving concrete piles and its installation.

Bed and reverse methods are used to drill boreholes.

Earth Drill Method 1 For example, excavation using the Benotoe method involves press-fitting a casing tube with a tubing device, and excavating the earth and sand in the cave with a hammer grab.
It consists of soil removal.

t7h, in the reverse method, the hole wall is protected by a no-casing head difference of 0.2 Kt/- or more (-membrane pressure is groundwater level + 2 m or more water head in the hole) and a mud film created by muddy water to protect the hole wall. This is a configuration that performs the following. Furthermore, the earth drilling method uses a casing pipe to protect the light surface of the ground, and excavates deeper than that using a stabilizing liquid unless bare digging is possible.

When an excavation hole is bored using each of the above construction methods, a tremie pipe is built in the hole, and a concrete pile is driven using the tremie pipe as shown in Fig. 1.2.

Slime, which is the result of fine-grained soil floating in the water in the borehole settling at the bottom of the borehole, or accumulated earth and sand during excavation, and spacers fixed to the cage and the sidewall of the borehole when constructing the reinforcing steel cage. There is a means to remove the slime that is deposited by the friction of the earth and sand that falls and accumulates. For example, a water jet outlet is provided at the tip of the tremie tube, water is blown out from the water jet outlet, and precipitated slime is suspended by hydraulic power and removed from the bottom of the borehole.

Some require concrete piles to be driven afterwards.

In addition, an air jet pipe is connected to the tip of the tremie pipe, and the air discharged from the air jet outlet at the tip of the air jet pipe generates a rising water flow to lift the slime upward and remove it from the excavation hole. There was a construction method that involved driving concrete piles.

However, the water jet nozzle mentioned above only suspends the slime that settles at the bottom of the borehole.
The efficiency of removing slime from the borehole is extremely low, and furthermore, since only the slime in the approximate center of the 1"lljl bottom hole is removed, a large amount of slime remains in the same groove at the bottom of the borehole. In addition, the method using an air jet pipe can cause slime to float, and since the air flow simply lifts up and removes the water in the borehole, it is not possible to remove the accumulated slime using a moving bed. Nakatsunen. That ninth one.

When driving concrete piles, as shown in Figure 2.

Since concrete piles are driven on top of slime, there is an inconvenience that the slime accumulated at the bottom of the excavation hole makes it impossible to firmly support the piles, resulting in a decrease in supporting capacity.

Therefore, the purpose of the present invention is to eliminate lime invasion that accumulates at the bottom of an excavation hole almost completely, to drive concrete piles directly and reliably onto the support layer, and to form cast-in-place concrete piles with high bearing capacity. To realize a concrete pile driving method and its equipment.

・The cast-in-place concrete pile driving device of the present invention will be described below based on the drawings. ``In Figures 3 to 5, 2 is a tremie pipe of the cast-in-place concrete pile driving device of the present invention.

4 is an umbrella-shaped member, 6 is a water jet pipe, 8 is a water jet ejection part, 10 is an air jet pipe,
12 is an air jet outlet. Said tray 2-pipe 2
An annular member 4 having a flared shape is attached to the tip 2a of the umbrella member 4, a quarter jet vibro is connected to the tip of the umbrella member 4, and a plurality of water jet nozzles 8at are provided at the tip of the water jet vibro. The water jet ejection part 8 is connected.

The blowing nozzle 8a of the water jet blowing part 8 is oriented downward or to the side so that a powerful fountain can be jetted downward or to the side. The tip portion 2a of the tremie tube 2
An air jet pipe 10 is connected upwardly, and an air jet discharge port 12 is formed at the tip of the pipe 10. Further, an air compressor (not shown) is connected to the beginning of the pipe 10 so that compressed air can be supplied.

Since it is configured as described above, it operates as follows. Slime S deposited at the bottom of the hole H after drilling the hole H using the above-mentioned PET, reverse, earth drilling method, etc.
eliminate. Therefore, the tip 2a of the tremie 1#2
Water jet spouting part 8 at the tip of the umbrella-shaped member 4 attached to the
Water is spouted downward and to the sides from a plurality of spout ports 8a,
The accumulated slime 5t-t is suspended. Simultaneously with the above operation, air is supplied to the air jet pipe 10 using air pressure afH, and is discharged from the vicinity of the tip 2a of the tremie tube 2 into the pipe 2 through the air jet outlet 12.

Then, the air flow discharged from the discharge port 12 causes an upward flow of water in the pipe 2, and the action of the umbrella-shaped member 4 causes a wide range of slime S to be sucked into the pipe 2. A large amount of slime can be sucked out.

Then, concrete piles are driven through the process of pouring concrete C. At this time, the means for separating the umbrella-shaped member 4 crushed by the distal ga portion 21 of the tremie tube 2 is performed by, for example, cutting a hanging means from the ground surface,
Alternatively, the tremie tube can be separated by releasing the fixing means by turning the tremie tube, for example, by half a turn.

Next, a method for driving cast-in-place concrete piles using the above-mentioned casting-in-place concrete pile driving apparatus according to the present invention will be described in detail.

As shown in Figure 3, the aforementioned bet and reverse.

The drilled hole H is completed by an appropriate method such as the earth drilling method, and when reinforcing bars and K are installed in the hole H, a plurality of spacers P are fixed in order to maintain the center position of the reinforcing bars and K.
Cart K was built.

Next, a tray-pipe is built into the hem C. Then, water is blown out from the spout 8a of the quarter-jet spout 8 downward and to the side, and the slime S deposited at the bottom of the hole H is suspended. At the same time, the floating slime S is sucked into the tremie tube 2 by the air flow discharged from the air jet outlet 12 near the tip of the tremie tube, and is removed by the rising water flow.

Next, after removing the slime S as shown in FIG. 4, concrete C is poured onto the plunger R. Then, the plunger R moves down to the vicinity of the tremie tube tip 2a and reaches the umbrella-shaped member 4 while expelling the water in the tremie tube 2 due to the weight of the concrete C. Then, when gradually pulling up the tremie tube 2, the umbrella-shaped member 4 is separated by appropriate means, and the umbrella-shaped member 4 is
is left buried in the concrete C at the bottom of the excavation hole H, as shown in FIG. Next, while pulling up the tremie 112, the concrete C is discharged into the excavated hole H from the tremie tube tip 2a by its own weight.

It should be noted that the above-mentioned embodiment shows one example of the method and apparatus for driving cast-in-place concrete piles according to the present invention, and it is possible to make various applications and modifications without departing from the spirit of the present invention. Of course.

For example, as shown in phantom lines in FIG. 6, if the air jet outlet 12 is fixedly installed in the tremie tube 2 and configured so that the air flow is directed along the inner wall of the tube 2 and forms a spiral, a vortex flow can be generated. This allows the slime to be effectively collected in the center of the tube and pushed up and removed. Similarly, by directing the water jet outlet in the tangential direction of the circumference and generating a swirling flow of water around the slime, the slime is accumulated almost directly below the tremie tube, and the slime is effectively suctioned and removed. It can also be configured.

As is clear from the above description, according to the present invention, since the tremie tube is provided with an umbrella-shaped member T-shaped at the tip end, the slime can be forced to float and the floating slime can be inhaled effectively. 1+: The slime deposited at the bottom of the borehole can be effectively expelled from the borehole by the water jet spout and the air jet outlet. For this reason, the concrete pile can be firmly driven into the support layer, which has the remarkable effect of increasing the bearing capacity of the concrete pile.

[Brief explanation of the drawing]

Figure 1.2 shows the conventional plunger type tremie construction method,
FIG. 1 is a vertical cross-sectional side view showing the fc state with a plunger installed in the tremie pipe, and FIG. 2 is a vertical cross-sectional side view showing the state in which concrete has been poured into the tremie pipe and pile driving has begun. 3 to 5 show embodiments of the present invention, FIG. 3 is an enlarged longitudinal sectional view showing the state when removing slime, FIG. 4 is an enlarged longitudinal sectional view showing the state in which concrete is poured into the tremie pipe, and FIG. FIG. 5 is an enlarged vertical cross-sectional view showing the state in which the pile is being driven. FIG. 6 is an enlarged cross-sectional plan view of a tremie tube showing another embodiment. In the figure, 2 is a tremie tube, and 4 is an umbrella-shaped member. 6 is a water jet pipe, 8 is a water shed ejection part, 9a is a nozzle, 1O is an air jet pipe, 12 is an air jet outlet, H is a drilling hole, is iron, P is a spacer, S is a slime, R is a plunger , C is concrete.

Claims (1)

[Claims] 1. A tapered umbrella-shaped member is attached to the distal end of the tremie tube, and an annular quarter-jet ejection part having a large number of ejection ports is provided at the periphery of the distal end of the umbrella-shaped member. A quarter jet pipe is communicated with the water jet ejection part, an air jet discharge port is provided near the tip of the tremie pipe and communicated with the air jet pipe, and the tremie pipe is built into the excavation hole to connect the quarter jet. Water is jetted from the jet port to forcibly suspend the slime deposited at the bottom of the borehole, and the compressed air jetted from the air jet discharge port generates an upward flow of water in the tremie tube, and this upward flow is A method of driving cast-in-place concrete piles in which the floating slime is sucked into a tremie pipe and removed, and then cement is poured under pressure. 2. Attach an umbrella-shaped member that widens toward the end of the tremie tube, and provide an annular quarter-jet ejection part with a large number of ejection ports on the periphery of the distal end of the umbrella-like member. 1. A cast-in-place concrete pile driving device, characterized in that a water jet pipe is connected to the pipe, and an air jet outlet is provided near the tip of the pipe to communicate with the air jet pipe.