JP2000001847A - Formation method of underground pile and formation monitoring mechanism thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a formation method of an underground pile and a formation monitoring mechanism thereof capable of decreasing a sludge moving quantity while taking advantage of a good feature of a conventional example and settling damage to an injection pipe caused by abrasion. SOLUTION: A monitoring mechanism 7 is built in the lower part of a hardener injection pipe 5, a hardener G is continuously jetted from a jet nozzle 7a of a jet pipe attached to the monitoring mechanism 7 in the direction of a radius of the hardener injection pipe 5, the hardener injection pipe 5 is pulled up to drive while swinging and driving the hardener injection pipe 5, the peripheral ground is cut with turning jet of compressed air A and the hardener G to be continuously jetted, an unsolidified pile P is formed in the cut area 11, and a foundation structural body 13 is formed in the ground by solidifying the unsolidified pile P. The jet pipe is constituted of a rigid stirring rod 20, and a bedrock in a rod swing area is so constituted that it can be directly excavated by the stirring rod 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an underground pile, which serves as a foundation structure such as a water stop wall, a continuous underground wall, or a foundation ground, and a construction apparatus applied to the method.

[0002]

2. Description of the Related Art As an apparatus for forming an underground pile of a jet grout type, one disclosed in, for example, Japanese Patent Application Laid-Open No. 6-185047 proposed by the present applicant has been known. FIG. 4 is a schematic configuration diagram of a jet grout type underground pile forming apparatus, and FIG. 3 shows a swivel (FIG. (A)) and a monitor mechanism (FIG. (B)) of the forming apparatus. Hereinafter, this conventional example will be described with reference to FIGS.

As shown in FIG. 4, this underground pile forming apparatus M includes an injection pipe turning / elevating drive unit 1, a hardening material ultra high pressure supply unit 2, an ultra high pressure water supply unit 3, and a compressed air supply unit 4.
And a hardening material injection pipe 5 composed of a triple pipe supported by the injection pipe turning / elevating drive device 1. At the upper end of the hardening material injection pipe 5, the hardening material injection pipe 5 and the hardening material ultra-high pressure A swivel 6 that connects the supply device 2, the ultrahigh-pressure water supply device 3, or the compressed air supply device 4 is connected, and a monitor mechanism 7 is connected to a lower end of the hardening material injection pipe 5. FIG.
Reference numeral 15 denotes a kneader for kneading a hardening material G such as cement milk, 16 denotes a reservoir, 28 denotes a mud pump for removing the mud 12 discharged from the upper end of the vertical hole 10a, and 29 denotes a vacuum car.

As shown in FIG. 3A, the swivel 6 has a jet inlet 6a for ultra-high pressure water or hardening material opened at the upper part of the swivel main body 60, and communicates with the jet inlet 6a. A jet passage 6e extending to the lower end surface along the axis, and an air inlet 6c opened at the lower part
An ultra-high pressure water inlet 6b opened in the middle, an ultra-high pressure water passage 6f communicating with the ultra-high pressure water inlet 6b, and an air inlet 6c.
And an air passage 6g communicating with the air passage. The ultrahigh-pressure water passage 6f and the air passage 6g are each formed in an annular shape in cross section around the jet passage 6e.

As shown in FIG. 3 (B), the monitor mechanism 7 comprises a monitor body 70 and a sleeve 80 which is externally fitted and fixed below the monitor body 70.
A blade bit 8 for a vertical hole is provided on the outer peripheral surface of the blade, and a drill bit 9 is provided on a lower surface of the sleeve 80. A flexible injection pipe 83 for injecting a hardening material is assembled through the sleeve 80. Further, a jet passage 7e for ultra-high pressure water or a hardening material is formed vertically in the monitor body 70, and an annular ultra-high pressure water passage 7f and an air passage 7g are independently formed outside the jet passage 7e. Have been. An injection nozzle 7b communicating with the ultrahigh-pressure water passage 7f is opened in an upper portion of the monitor main body 70, and an air nozzle 7d communicating with the air passage 7g is opened around the injection nozzle 7b.

A water supply nozzle 75 is opened at the lower end of the jet passage 7e. A check valve 74 is provided upstream of the water supply nozzle 75, and a ball valve seat 72 is further provided upstream of the water supply nozzle 75. Thus, a jet communication passage 81 is formed. The jet communication passage 81 communicates with the jet passage 7e at an upstream side of the ball valve seat 72. The jet communication passage 81 communicates with the jet pipe 8 for hardening material through a nipple 81a.
An air injection pipe 86 communicates with the air communication path 85 via a nipple 85a.
3 and 86 are configured to be able to protrude in the pipe radial direction via a pipe outlet metal 88 fixed to the lower side surface of the sleeve 80.

Each of the injection tubes 83 and 86 is formed of a bendable pressure-resistant hose.
As shown in (C), an injection nozzle 7a is formed at the center of the front, and air nozzles 7c are formed on both sides of the injection nozzle 7a. Then, the ultra-high pressure water W is injected from the injection nozzle 7b provided at the upper part of the monitor mechanism 7 to excavate a nearby area in advance, and then the pressure hose 83 is directly extended in the pipe radial direction by the supply pressure of the compressed air A. Then, by injecting the hardening material G, the reaching distance is greatly increased, and the outer peripheral area is excavated. As a result, the diameter of the substructure 13 can be further increased, and the substructure can be formed in a short time. However, there is room for improvement in the following points.

[0008]

Since the injection pipe 83 is formed of a bendable pressure-resistant hose, the surrounding ground cannot be directly excavated by the injection pipe 83. For this reason, it is necessary to inject the ultra-high pressure water W from the injection nozzle 7b provided on the upper part of the monitor mechanism 7 to excavate a nearby area in advance. Due to this preliminary excavation, the amount of sludge discharged is increased by the use of the ultrahigh-pressure water W, and the cost of sludge treatment is also high. Another drawback is that the pressure-resistant hose is easily damaged by wear. The present invention, while taking advantage of the above advantages of the conventional example, while significantly reducing the amount of sludge and reducing the construction cost,
An object of the present invention is to provide a method for forming an underground pile capable of reducing damage to an injection pipe due to wear and a monitor mechanism for forming the underground pile.

[0009]

In order to solve the above-mentioned problems, the present invention is configured as follows. That is, claim 1
According to the invention described in the above, in the conventional underground pile creation method, the injection pipe 83 is constituted by a rigid stirring rod 20,
It is characterized in that the ground in the rod turning area L can be directly excavated by the stirring rod 20.

According to a second aspect of the present invention, there is provided a monitor mechanism configured to project the injection pipe 83 in the radial direction of the hardened material injection pipe 5 by the pressure of the compressed air A or the hardened material G. Is constituted by a rigid stirring rod 20,
The stirring rod 20 is vertically pivotally supported below the monitor mechanism 7 so as to be switchable between a hanging posture J and a protruding posture K in the radial direction of the tube.

[0011]

According to the first aspect of the present invention, in the conventional method of forming an underground pile, the injection pipe 83 is used.
Is constituted by a rigid stirring rod 20, and the stirring rod 20
As a result, since the ground in the rod turning area L can be directly excavated, it is not necessary to provide an injection nozzle above the monitor mechanism 7 as in the conventional example, and there is no need to pre-drill with ultra-high pressure water. As a result, the amount of sludge discharged is reduced as much as the use of ultra-high pressure water is not required, and the cost of the sludge treatment is reduced, so that the construction cost can be reduced.

(B) According to the first aspect of the present invention,
Since the injection pipe 83 is formed of the rigid stirring rod 20, breakage due to wear can be significantly reduced.

(C) According to the second aspect of the present invention, the injection pipe 83 is constituted by a rigid stirring rod 20, and the stirring rod 20 is pivotally supported below the monitor mechanism 7 in a vertically swingable manner.
Since it is configured to be switchable between the hanging posture J and the protruding posture K in the radial direction of the pipe, the hardening material injection pipe 5 with the monitor mechanism 7 is inserted into the target depth in the ground, and the stirring rod 20
Is driven by the compressed air A or the pressure of the hardening material G in the radial direction of the hardening material injection pipe 5 while the hardening material injection pipe 5 is driven to rotate, so that the stirring rod can be excavated with ultra high pressure water without prior excavation. At 20, the ground in the rod turning area L can be directly mechanically excavated. Thereby, the above effects (a) and (b) can be surely achieved.

[0014]

Embodiments of the present invention will be described below in more detail with reference to the drawings. FIG. 1 shows a monitor mechanism according to the present invention. FIG. 1 (A) is a longitudinal side view of the monitor mechanism, and FIG. 1 (B) is a front view of a main part of the monitor mechanism. As shown in FIGS. 1A and 1B, the monitor mechanism 7 includes an upper monitor main body 71 connected to a lower portion of a hardening material injection pipe 5 described later, and a lower monitor main body 72 integrally connected thereto. , The spindle 2 on the lower monitor body 72
1 and a stirring rod 20 which is supported so as to be vertically swingable.

The upper monitor main body 71 has a hardening material jet passage 7e formed along the axis thereof and an air jet passage 7f formed annularly outside the jet passage 7e. The lower monitor main body 72 has a cylinder bore 73 communicating with the lower end of the hardening material jet passage 7e.
And a piston 74 which is slidably fitted in the cylinder bore 73 is provided.
Is lowered to drive the stirring rod 20 via the connecting rod 75 from the hanging posture J indicated by a virtual line to the protruding posture K in the radial direction of the tube.

The stirring rod 20 constituting the injection pipe 83
Is made of a hard metal material having rigidity.
The stirring rod 20 includes a hardening material jet passage 8a formed along the axis thereof, an air jet passage 8b formed annularly outside the jet passage 8a, and a tip nozzle 22. And in the tip nozzle 22,
As shown in FIG. 1 (B), a hardening material injection nozzle 7a and a surrounding air injection nozzle 7c are formed.
The jet of the hardening material G jetted from a is guided by the compressed air A to increase the flight distance.

The hardening material jet passages 7e and 8a and the air jet passages 7f and 8b of the upper monitor main body 71 and the stirring rod 20 are connected to the communication bases 17a and 17b, respectively.
27a, 17c, 27c and communication hoses 23, 24 which can be bent and deformed. FIG. 1 (A)
In the figure, the communication mouthpieces 27a and 27c of the stirring rod 20 are arranged below the stirring rod 20 in the protruding posture K.
This is because when the ground is excavated in the swirling area while the stirring rod 20 is swiveled up and lifted, the communication mouthpieces 27a and 2
7c and communicating hoses 23 and 24 connected thereto
This is to avoid damage.

2 (a) to 2 (f) are schematic views showing the procedure of a method of forming an underground pile according to the present invention, wherein FIG. Fig. (C) is a stir rod protruding step, and Fig. (D)
FIG. 3E shows a formation start step, FIG. 3E shows a formation step, and FIG. Hereinafter, this construction method will be described with reference to FIGS.
A description will be given based on (f).

A. Lead Pipe Drilling Step << FIG. 2 (a) >> In the lead pipe drilling step, the pile forming device M is installed on the ground, and the lead pipe 10 (about 140φ) is inserted to a predetermined depth in the ground. The pile forming apparatus M is similar to the conventional example in that a turning / elevating drive unit 1, a hardening material ultra-high pressure supply device 2, an ultra-high pressure water supply device 3 and a compressed air supply device 4, a leading pipe 10, a curing A material injection pipe 5 and the like are provided.

In the leading pipe piercing step, a dedicated swivel 6A is connected to the upper end of the leading pipe 10, and a dedicated monitor mechanism 10B having a metal crown 9 is connected to the lower end. The tip conduit 10 is set up vertically at a predetermined construction position, a bentonite muddy water supply device is connected to the muddy water inlet 6a of the swivel 6A, and about 0 to 50 atm of bentonite muddy water W is discharged downward from the monitor mechanism 10B. Lifting drive 1
To lower while rotating the leading conduit 10,
While drilling the vertical hole 10 a with the metal crown 9,
0 is inserted to a predetermined depth in the ground. At this time, the bentonite muddy water W is circulated.

B. Double Pipe Building Step << FIG. 2 (b) >> In the double pipe building step, the hardened material injection pipe 5 made of a double pipe is inserted into the front pipe 10 using the front pipe 10 as a guide. Next, the leading conduit 10 is pulled up. A swivel 6 is connected to the upper end of the hardening material injection pipe 5 and a monitor mechanism 7 according to the present invention is previously provided at the lower end (FIG. 1).
Are connected. Reference numeral 28 denotes a sludge pump, 25 denotes a suspension hook for suspending the swivel 6, the hardening material injection pipe 5, and the like. Is used from the viewpoint of safety when several pipes are added or when the leading conduit 10 is changed by the chuck mechanism of the turning / elevation driving device 1.

C. Stir Rod Protruding Step << FIG. 2 (c) >> In the stirring rod protruding step, the jet inlet 6 of the swivel 6 is used.
a, and the compressed air supply device 4 is connected to the air inlet 6c. By injecting the hardening material G, the piston 74 is operated by the supply pressure to give a protruding output to the stirring rod 20, and the pipe turning / elevation driving device 1 is operated to move the hardening material injection pipe 5 to a predetermined position. By rotating and driving at the rotation speed, the posture of the stirring rod 20 is switched from the hanging posture J shown in FIG. 1A to the projecting posture K in the pipe radial direction while excavating the surrounding ground with the stirring rod 20. .

D. Creation Start Step << FIG. 2 (d) >> In the creation start step, the hardening material G is injected from the injection nozzle 7a of the stirring rod 20 into the air nozzle 7 around the injection nozzle 7a.
c, high-pressure air is continuously injected in the pipe radial direction to cut the ground around the pipe. Thereby, if the injection test is successful, the process proceeds to the forming process.

E. Creation Step << FIG. 1 (d) >> By operating the turning / pulling drive device 1 to drive the hardening material injection pipe 5 to pull up while turning, the stirring rod 20 excavates the ground in the rod turning area L and The ground of the outer peripheral area is cut by the jet of the hardening material G and the high-pressure air A continuously jetted at a high pressure from the tip of the stirring rod 20,
An uncured pile is formed in the cutting area 11. By the way,
The discharge pressure of the hardening material G is 100 to 400 kg / cm ² , the discharge amount is 70 to 300 l / min, and the discharge pressure of the compressed air is 6 to 3
0 kg / cm ² and the discharge amount are set to 1.5 to 15.0 m ³ / min.

At this time, the jet of the compressed air A and the hardening material G is less attenuated by the length of the stirring rod 20,
The jet of the hardening material G is guided by the compressed air A, flies farther and cuts the ground greatly, and kneads the hardening material G and the excavated mud by turning the stirring rod 20 and the hardening material jet. Accordingly, a large uncured pile P can be formed, and the formation time of the substructure 13 can be further reduced.

Excess sludge is pushed up by the hardening material G ejected from the injection nozzle 7a and the high-pressure air A injected from the air nozzle 7c, and is discharged to the ground through a gap between the perforation 10a and the hardening material injection pipe 5. Is done. This sludge is removed by the sludge pump 28 and the vacuum car 19. When the creation of the target area is completed, the hardening material G
And supply of high-pressure air A is stopped.

E. Filling the hole << FIG. 2 (e) >> By stopping the supply of the hardening material G,
Is located in the hanging posture J. In this state, the hardening material injection pipe 5 is pulled out to the ground, and the inside of the pipe is washed with fresh water. Thereafter, if necessary, the perforations 10a are filled. Then, it moves to the next formation point, and forms an uncured pile P in the soil in the same procedure. When the uncured pile P is cured, the substructure 13 is formed in the ground.

According to this method, the amount of sludge can be significantly reduced as compared with the conventional method using the monitor mechanism shown in FIG. By the way, when compared with this method and the conventional method, the formation time per 1 m of the formation depth, the amount of hardening material used,
The estimated values of the amount of sludge are as follows. However, the formation conditions are sandy soil, the N value is 30, and the formation diameter is 2000φ. Construction time Amount of hardening material used Amount of mud drained This method 16 minutes 1.44 m ³ 1.584 m ³ Conventional method 16 minutes 1.44 m ³ 3.168 m ³

In the above embodiment, the stirring rod 20 is projected in the radial direction of the pipe by the supply pressure of the hardening material G. However, the stirring rod 2 is supplied by the supply pressure of the high-pressure air A.
0 may be made to protrude in the pipe radial direction. Further, the drive mechanism for projecting the stirring rod 20 in the radial direction of the tube is not limited to the one including the piston and the connecting rod, and can be implemented with appropriate modifications.

[Brief description of the drawings]

FIG. 1 is a sectional view of a monitor mechanism according to the present invention.

2 (a) to 2 (f) are schematic diagrams showing the procedure of an underground pile forming process according to the present invention.

3A and 3B show a conventional example, in which FIG. 3A is a sectional view of a swivel, and FIG. 3B is a sectional view of a monitor mechanism.

FIG. 4 is a schematic diagram of an underground pile creation device.

[Explanation of symbols]

5: hardening material injection pipe, 7: monitoring mechanism, 7a: injection nozzle, 7c: air nozzle, 11: cutting area, 13: basic structure, 20: stirring rod, 83: injection pipe (stirring rod), A: compression Air (high pressure air), B: hanging position of stirring rod, C: projecting position of stirring rod, G: hardening material, P
... uncured pile.

Claims (2)

[Claims] 1. A monitor mechanism (7) is attached to a lower portion of a hardening material injection pipe (5), and the hardening material (G) is hardened from an injection nozzle (7a) of an injection pipe 83 attached to the monitor mechanism (7). The hardened material injection pipe (5) is driven to swirl while the compressed air (A) is continuously injected from the air nozzle (7c) around the material injection pipe (5) while being continuously injected in the radial direction of the material injection pipe (5). Compressed air (A) continuously ejected from the air nozzle (7c) and the ejection nozzle (7a) by pulling up while
The surrounding ground is cut by each swirling jet of the hardening material (G) and an unhardened pile (P) is formed in the cutting area (11), and the unhardened pile (P) is hardened. In an underground pile forming method configured to form a substructure (13) in the ground, the injection pipe (83) is formed by a rigid stirring rod (20), and the injection pipe (83) is formed by the stirring rod (20). An underground pile creation method, characterized in that the ground in the rod turning area (L) can be directly excavated. 2. A monitor mechanism wherein the injection pipe (83) is projected in the radial direction of the pipe by the pressure of compressed air (A) or hardening material (G). (20), the stirring rod (20) is supported vertically below the monitor mechanism (7) so as to be vertically swingable, and can be switched between a hanging posture (J) and a protruding posture (K) in the radial direction of the pipe. A monitor mechanism characterized in that: