JP2003147771A - Pile extracting construction method and its device, improved ground and ground improvement construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pile extracting construction method and a pile extracting device requiring not so much large force when extracting a pile, and reducing a work cost, and to provide the improved ground and a ground improvement construction method suitable for backfilling a hole after extracting the pile in strength equal to the surrounding ground. SOLUTION: A foundation pile 1 is easily extracted by softening the surrounding ground 2 of the foundation pile 1 by blowing high pressure water in a concentrically circular shape with the foundation pile 1 against the surrounding ground 2 of the foundation pile 1 by a high pressure water injector 10. Cement, bentonite, and water are injected into a pile extracting hole 5 by extracting the foundation pile 1, and are agitated together with sediment around the hole, and the surrounding ground 2 and compressive strength are equally adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for extracting a pile suitable for extracting an existing foundation pile from the soil when rebuilding a building, and a method for filling the hole after the foundation pile is extracted. Improved ground and ground improvement method.

[0002]

2. Description of the Related Art Generally, when an existing building is demolished and a new building is constructed, the old foundation pile used in the existing building has deteriorated considerably, and Since the number, size, length, etc. of foundation piles do not match, it was necessary to pull out the piles once and refill them to make the holes of the piles have the same strength as the surrounding ground. .

Therefore, in the conventional construction method,
When pulling out existing foundation piles, after excavating the surrounding ground extensively to expose a considerable portion of the foundation piles, attach wires or chains to the head and forcibly pull out using a hydraulic crane, etc. Was being done. In addition, when backfilling the holes of the foundation piles, stones, earth and sand, etc. were backfilled or concrete was poured into the holes of the foundation piles.

[0004]

However, in the conventional construction method, when the foundation pile is pulled out, a construction machine such as a crane for extraction having a considerably large pulling capacity is required, and the construction machine becomes large in size and expensive. Therefore, there was a problem that the construction cost increased.

Further, in the case of backfilling, there is a problem that when backfilling with stones, earth and sand, etc., a cavity is formed inside and the strength becomes lower than the ground around the hole. It was an obstacle. Furthermore, when concrete is poured into the holes of foundation piles, on the contrary, the strength becomes extremely higher than the ground around the holes, and there is a problem that it will hinder the next foundation work. There was a need.

The present invention has been made in view of such a conventional problem, and provides a pile removing method and a pile removing apparatus which do not require a great force when pulling out a pile and are low in construction cost. At the same time, it is an object of the present invention to provide an improved ground and a ground improvement method suitable for backfilling a hole after pulling out a pile to the same strength as the surrounding ground.

[0007]

In order to achieve the above object, a pile removing method according to the present invention is a pile removing method for pulling out a pile fixed to the ground, in which high pressure is applied to the ground around the pile. The pile around the pile is softened by blowing high-pressure water with a water jet device to pull out the pile.

In the pile removing method according to the present invention, when the pile is removed, high-pressure water is sprayed to soften the ground around the pile, so that the pile can be easily removed. There is no need to excavate over a wide area, and the time and effort required for construction can be greatly reduced compared to conventional construction methods. In addition, a great amount of force is not required when pulling out the pile, and the construction cost can be kept low.

In the pile removing method according to the present invention, it is preferable that high-pressure water is sprayed on the ground around the pile while the high-pressure water injection device is pressed into the ground by a press-fitting device or its own weight. The pile removing device according to the present invention includes a high-pressure water jetting device for surrounding the pile and blowing high-pressure water to the ground around the pile to soften the ground, and the high-pressure water jetting device is fixed to the lower end of the high-pressure water jetting device. And a guide member for moving the high-pressure water jetting device along the pile. The pile removing device according to the present invention is suitable for carrying out the above-described pile removing method according to the present invention.

The pile removing device according to the present invention preferably comprises a press-fitting device for press-fitting the guide material together with the high-pressure injection device into the ground.

The improved ground according to the present invention is characterized in that a mixture of earth and sand, cement, bentonite and water around the hole is provided in the hole formed in the ground. The improved ground according to the present invention has the same strength as the ground around the hole and is suitable for making the ground suitable for the next foundation work.

The ground improvement method according to the present invention is such that cement, bentonite, and water are injected into a hole formed in the ground and stirred together with the earth and sand around the hole to adjust the compressive strength to be equal to that of the surrounding ground. It is characterized by doing.

In the soil improvement method according to the present invention, cement, bentonite, and water are injected into the hole after the foundation pile is removed and the mixture is stirred with the earth and sand around the hole, so that the backfilled ground is It is easy to get used to the surrounding soil.
Therefore, unlike the ground backfilled with only gravel, the backfilled ground does not become unstable. Further, unlike the soil backfilled with concrete, the soil backfilled can prevent it from becoming too hard. Furthermore, by adjusting the compressive strength to be equal to that of the surrounding ground, the ground can be made appropriate for the next foundation work.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part of a pile removing device used in a pile removing method according to an embodiment of the present invention. The pile removing device includes a high-pressure water jetting device 10 that blows high-pressure water concentrically with the foundation pile 1 onto the ground 2 around the foundation pile 1 to soften the ground 2, and a lower end of the high-pressure water jetting device 10 fixed to the foundation. Steel sheet pile 13 formed longer than pile 1 and this steel sheet pile 1
And a hydraulic press-fitting device 20 that presses the high-pressure water jetting device 10 into the ground by sandwiching 3 therebetween. Steel sheet pile 13
Is a guide member for moving the high-pressure water jetting device 10 along the pile.

The high-pressure water injection device 10 has a circular fountain pipe 11 for injecting high-pressure water around the foundation pile 1 and a cylindrical casing for guiding the fountain pipe 11 around the foundation pile 1. It is composed of 12 and. A steel sheet pile 13 for press-fitting the high-pressure water jet apparatus 10 is attached to the high-pressure water jet apparatus 10, and a water pipe 14 is attached along the steel sheet pile 13. A high-pressure hose 15 for supplying high-pressure water from the outside to the high-pressure water injection device 10 is connected to the upper end of the water conduit 14, and the high-pressure hose 15 is connected to an external high-pressure pump 16 and a water tank 17.

Further, the fountain pipe 11 is provided with nozzles 11a serving as high-pressure water jet ports facing downward at appropriate intervals. The nozzle 11a is provided by avoiding the mounting portion of the steel sheet pile 13 in consideration of efficiency and working time. Nozzle 11a
Are provided in the fountain pipe 11 at four locations, for example.

The hydraulic press-fitting device 20 for press-fitting the high-pressure water jetting device 10 is a known press-fitting device generally used for press-fitting and pulling-out of foundation piles. This press fitting device 20
Is a high-pressure water jetting device 1 via a steel sheet pile 13 by hydraulic pressure.
0 is pressed into the ground 2. This press fitting device 20
Is a reaction force stand 21 installed around the existing foundation pile 1.
And a fixed base 22 fixed on the reaction force base 21,
A movable table 23 that can move freely on the fixed table 22,
It comprises a press-fitting mechanism 24 attached to the movable table 23 and provided with a hydraulic cylinder. In addition, the press-fitting device 20 can press-fit the high-pressure water injection device 10 and can also pull up the high-pressure water injection device 10 in the opposite direction.

Since the press-fitting device 20 is press-fitted and withdrawn by hydraulic pressure, it can be constructed without vibration and noise.
The press-fitting device 20 has a capacity of 100 tons for press-fitting and 130 tons for pulling-out. In addition, remote control by radio control is also possible. further,
The press-fitting mechanism 24 can freely handle even a cylindrical pile or a U-shaped steel sheet pile by exchanging the attachment for gripping.

Next, a pile removing method using the thus constructed pile removing device will be described with reference to FIGS. 2 to 5. First, as shown in FIG. 3, the press-fitting device 20 is lifted up by the auxiliary crane 3 for each reaction force pedestal 21, and the foundation pile 1
Is set around (step S1 in FIG. 2). And
The high-pressure water jetting device 10 is set on the head of the foundation pile 1 (step S2 in FIG. 2). In addition, as shown in FIG. 1, the water conduit 14 is routed through a high pressure hose 15 to the external high pressure pump 1.
6 and the water tank 17 are connected.

Next, the external high-pressure pump 16 is operated to cause the high-pressure water jetting device 10 to move the foundation pile 1 around the foundation pile 1.
High-pressure water is sprayed concentrically with (step S in FIG. 2).
3). As an example, the water pressure in this case is 15 kg / cm ²
And the injection rate is 320 liters / minute. Then,
Since the ground around the foundation pile 1 is softened, the press-fitting device 20 starts press-fitting the steel sheet pile 13 and the high-pressure water jetting device 10 (step S4 in FIG. 2). In this case, the pressure is not so required, and the pressure is 0.5 m / min. When the press-fitting operation is continued in this way, as shown in FIG. 4, the high-pressure water jetting device 10 reaches the tip portion of the foundation pile 1, so the press-fitting is stopped (step S5 in FIG. 2).

Next, the foundation pile 1 is prepared to be pulled up (step S6 in FIG. 2), and as shown in FIG.
Pulling up by ~ 3 m (step S7 in FIG. 2). Therefore, the pulling up is stopped once and the sling wire is wound around the foundation pile 1 and set on the main winding of the auxiliary crane. Then, the foundation pile 1 is pulled up while dropping the mud of the foundation pile 1 with a high-pressure car wash machine (not shown) or the like (step S7 in FIG. 2).
Then, in parallel with the work of pulling up the foundation pile 1, the high-pressure water jetting device 10 is also pulled up by the press-fitting device 20 (FIG. 2).
Step S8). At this time, if the high-pressure water jetting device 10 is pulled up so that the casing 12 slides while contacting the side surface of the foundation pile 1, the mud around the foundation pile 1 can be dropped to reduce friction. Pile 1
Is easy to pull up, which is preferable.

Further, it is determined whether or not the foundation pile 1 is extended by welding or the like (step S9 in FIG. 2), and if it is long, gas cutting or the like is performed at the joint (step S in FIG. 2).
10) and pull up again (step S1 in FIG. 2).
1). If the foundation pile 1 is not long, pull it up as it is. In this way, the pulling up is completed (step S12 in FIG. 2). The extracted foundation pile 1 is moved to the place where the foundation pile 1 is placed, and the wire 4 is removed. In addition, the high-pressure water injection device 10 performs cleaning, and the auxiliary crane 3 presses the press-fitting device 2
0 is lifted together with the reaction force pedestal 21 and set around the next foundation pile 1, and the same pile removing work as the previous time is performed.

Depending on the hardness of the ground 2 and the length of the foundation pile 1, the press-fitting operation by the press-fitting device 20 may be omitted.
The ground 2 is softened into a muddy state only by the water pressure of the high-pressure water injection device 10, and the steel sheet pile 13 and the high-pressure water injection device 1 of the pile removing device 1
It is possible to settle down only by its own weight of 0 or the water pressure of the high-pressure water jet device 10, and it is not necessary to consume extra energy.

In the pile removing method described above, the use of the high-pressure water jetting device 10 eliminates the need to excavate the ground 2 around the foundation pile 1 in a wide area, so that the labor and time required for the construction can be reduced by the conventional method. It can be greatly reduced compared to. Further, by using the hydraulic press-fitting device 20, it is possible to perform the work without vibration and noise, so that it is possible to eliminate the inconvenience caused to the residents around the construction site.

Next, a ground improvement method for backfilling the hole in which the foundation pile 1 has been removed as described above to improve the ground will be described. The excavator 30 used in this ground improvement method is an improved excavator, and as shown in FIG. 6, a stirring bit 33 is attached to the tip of a rotating excavating rod 32 attached to a carriage 31. There is. An excavation claw 34 and an agitation blade 35 are attached to the agitation bit 33, and a cement milk inlet 36 is provided at the tip. Then, the drilling rod 32 and the stirring bit 33
Has a hollow interior, and this drilling rod 32
A pump hose 37 for pumping cement milk is connected to the upper end of the.

As shown in Table 1, cement milk is formed by mixing cement (Portland cement), bentonite and water. The amount of bentonite mixed in the cement milk is about 10% with respect to the cement.
The amount of cement, bentonite, and water in the amounts shown in Table 1 are mixed per 2.543 m ³ of earth and sand (original soil) around the piling hole 5. The compressive strength changes according to the amount of water, and the greater the amount of water, the smaller the compressive strength. The amount of water of the cement milk to be used is determined according to the compressive strength of the earth and sand around the pile punching hole 5.

[0027]

[Table 1]

In order to backfill the pile punching hole 5 with the excavating device 30, first, the pile punching hole 5 in which the foundation pile 1 is pulled out is placed in the surrounding ground 2.
It is filled with earth or coarse sand. Then, the drilling device 30
Excavate the ground 2 while rotating the excavation rod 32 with
At the same time, the cement milk is pumped by a cement milk pump (not shown), and the cement milk is injected into the pile extraction hole 5 of the ground 2 through the injection port 36. In one example, the cement milk injection rate is 50 liters / minute. In this way, when the stirring bit 33 reaches the tip position of the pile punching hole 5, the excavation is stopped and the excavation rod 32 is pulled up while rotating.

This working step is repeated twice to thoroughly mix the cement milk and the surrounding ground 2. The ground thus improved comprises a mixture of earth and sand, cement, bentonite and water in the hole formed in the ground. In the improved ground, the soil quality of the pile punching holes 5 is made sufficiently close to that of the surrounding ground 2, and the compressive strength is adjusted to be equal to the compressive strength of the surrounding ground 2.

According to the ground improvement method described above, since the cement milk and the surrounding ground are properly mixed in the backfilled ground, the soil quality is similar to that of the surrounding ground.
Moreover, unlike the ground where only the gravel is backfilled, the ground does not become unstable. Further, unlike the ground that is backfilled with concrete, the ground does not become too hard, and the strength is almost the same as the surrounding ground. Therefore, when the next foundation work is performed, the work becomes easy. This ground improvement method is not limited to the case of backfilling the pile punching holes 5, but can be applied to other ground.

[0031]

EFFECTS OF THE INVENTION According to the present invention, a pile removing method and a pile removing device which do not require a large force when pulling out a pile and are low in construction cost are provided. It is possible to provide an improved ground and a ground improvement method suitable for backfilling to the same strength as the ground.

[Brief description of drawings]

FIG. 1 is a front view showing a main part of a pile extracting device according to an embodiment of the present invention.

FIG. 2 is a flow chart showing a pile removing method according to the embodiment of the present invention.

FIG. 3 is a front view showing a prepared state of the pile removing method according to the embodiment of the present invention.

FIG. 4 is a side view showing a press-fitted state of the pile removing method according to the embodiment of the present invention.

FIG. 5 is a front view showing a pulled-up state of the pile removing method according to the embodiment of the present invention.

FIG. 6 is a front view showing an excavation device used for the ground improvement method according to the embodiment of the present invention.

[Explanation of symbols]

1 foundation pile 2 ground 3 auxiliary crane 4 wires 5 Pile hole 10 High-pressure water injection device 11 fountain pipe 11a nozzle 12 casing 13 Steel sheet pile 14 water conduit 15 High pressure hose 16 High pressure pump 17 Water tank 20 Press-fitting device 21 Reaction force stand 22 Fixed base 23 Mobile platform 24 Press-fitting mechanism 30 drilling equipment 31 dolly 32 Drilling rod 33 Stirring Bid 34 Excavation claw 35 Stirrer 36 inlet 37 High pressure hose

Claims (6)

[Claims] 1. A pile removing method for removing a pile fixed to the ground, which comprises softening the ground around the pile by spraying high-pressure water onto the ground around the pile with a high-pressure water jet device. A method of removing a pile, which comprises removing the pile by pulling the pile. 2. The pile removing method according to claim 1, wherein high pressure water is sprayed onto the ground around the pile while the high pressure water injection device is pressed into the ground by a press-fitting device or its own weight. 3. A high-pressure water jetting device for surrounding the pile and spraying high-pressure water on the ground around the pile to soften the ground.
The high-pressure water injection device is fixed to the lower end, and a guide member for moving the high-pressure water injection device along the pile is provided. 4. The pile removing device according to claim 3, further comprising a press-fitting device for press-fitting the guide material together with the high-pressure injection device into the ground. 5. The improved ground, characterized in that a mixture of earth and sand, cement, bentonite, and water around the hole is provided in the hole formed in the ground. 6. A ground characterized by injecting cement, bentonite, and water into a hole formed in the ground and agitating the same with earth and sand around the hole to adjust the compressive strength to be equal to that of the surrounding ground. Improved construction method.