JPH07305351A - Method and device for cutting underground obstacle - Google Patents

Abstract

PURPOSE:To prevent surrounding earth and sand from entering by lowering a nozzle holder attached to the end of a kelly-bar into a hole drilled by a casing driver, and injecting high-pressure water horizontally from a nozzle for cutting the outer periphery of an underground obstacle left in a casing. CONSTITUTION:A cylindrical casing 2 is rotated and driven into the earth by a casing driver. When the casing 2 reaches an obstacle 10, it cuts the obstacle 10 into a columnar shape to obtain an obstacle 10a. After cutting of the obstacle 10 is complete, earth and sand left in the casing 2 are conveyed to the surface of the earth for removal. Next, a kelly-bar 3 is driven and rotated along the axis of the casing 2 via a connector 11 formed in the casing 2 and is connected in such a way as to freely move in the vertical direction. Then the top board of a nozzle holder 14 is secured to the lower end of the kelly-bar 3. Further, a monitor and control board 21 is lowered from the top surface of the obstacle 10a to a position corresponding to a desired thickness. Also, water with a polisher mixed therein is injected from a nozzle 15 by operation of both a high- pressure pump unit and a polisher feed tank 20, and the kelly-bar 3 is 180 deg. rotated alternately in opposite directions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cutting underground obstacles, which cuts underground obstacles remaining in a cylindrical casing having a blade tip at its tip and drilled while rotating.

[0002]

2. Description of the Related Art A casing driver having a cutting edge provided at its tip for drilling while rotating is known. Since a casing penetrates through existing obstacles such as an existing driving body, piles or boulders, the ground remaining in the casing. A method for removing middle obstacles (hereinafter, abbreviated as obstacles) has also been developed. The conventional method and its problems will be described below.

1. The method using the Hammaglab.

As shown in FIG. 8, if the obstacle t cut into a cylindrical shape by the casing 2 has a thickness t of about 300 m, it is easily gripped by the hammer mug 30 and remains in the casing 2. It is easy to remove the obstacle 10a to be removed. Reference numerals 7, 8 and 9 in the drawing denote an external tooth cutter, an internal tooth cutter and an internal surface cutter, respectively. However, for thick foundations such as foundations, underground beams or cast-in-place concrete piles, it is necessary to insert the claw deeply because it is heavy, but in reality it is difficult to insert and it is difficult to grasp and it requires a lot of labor and effort. It takes time.

2. Method using rocket hammer or chisel hammer ... Rocket hammer 4 in FIG.
At 0, the shoulder portion of the obstacle 10a is gradually crushed into a shape that is easy to grip, or the weight is reduced by the chisel hammer 50 in FIG. 10 to facilitate gripping with a hammer grab (see FIG. 8). This method requires construction time,
Noise and vibration are generated, making it difficult to apply in the field in urban areas and residential areas.

3. How to add internal cutters.

In FIG. 11, an auxiliary inner surface cutter 9a protruding further inward is added above the inner surface cutter 9 fixed to the tip of the casing 2 to reduce the outer diameter of the obstacle so that the casing 2 and the obstacle are separated from each other. However, the number of replacements of the casing cutter is troublesome, the increase of the gap S is limited, and a measure for improving the weight of the obstacle 10a. do not become.

4. How to use a small casing.

In FIG. 12, an obstacle 10 having a smaller diameter than the obstacle 10 is first cut by using a casing 2a having a smaller diameter.
Separate b. Since the obstacle 10b having a small diameter is lightweight, it can be easily grasped and removed by the hammer mug 30. Next in FIG.
In 3, the obstacle 10c cut by the predetermined casing 2 and hollowed out is separated. Obstacles 10 removed
Since c is lightweight, it can be easily grasped and removed by the hammer mug 30. However, this method has a problem in that the number of steps is increased and it takes a long working time. Therefore, it is necessary to prepare a casing having a different diameter, and when the small casing is pulled out, the surrounding earth and sand enter and the quality of the pile construction deteriorates.

A technique for cutting underground obstacles by jetting high-pressure water mixed with an abrasive is known as a so-called abrasive jet method. However, the further cutting of the large underground obstacle, which is cut into the cylindrical shape by the casing driver, is the cutting in the axial direction of the casing as described above, and therefore the above-mentioned problem cannot be solved.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for cutting an underground obstacle that does not allow dirt and sand to enter from the surroundings, is free from vibration noise, can slice an obstacle into circles, and is easy to work. And

[0012]

According to the present invention, there is provided an underground obstacle cutting method for cutting underground obstacles remaining in a cylindrical casing provided with a blade tip at its tip and drilled while rotating. Rotating the casing to cut the earth and sand and underground obstacles to form a gap between the casing and the underground obstacles in the radial direction of the casing, the step of removing the sediment in the casing, and the kelly bar to the casing shaft. Connecting on a line, fixing the nozzle holder with the nozzle attached to the kelly bar, inserting the nozzle into the gap, rotating in the direction of the axis of the casing, and in a direction orthogonal to the axis. And a step of jetting high-pressure water mixed with an abrasive from a nozzle to cut an underground obstacle in a direction perpendicular to the axis.

Further, according to the present invention, in the underground obstacle cutting device for cutting the underground obstacle remaining in the cylindrical casing having the blade tip provided at the tip and drilling while rotating, the tip of the casing is provided. An inner cutter that is attached and forms a gap between the casing and the underground obstacle in the radial direction, and is fixed to a kelly bar that is attached after the underground obstacle is cut into a cylindrical shape by the casing. A nozzle holder inserted into the gap between the intermediate obstacle and the nozzle, a nozzle mounted below the nozzle holder and arranged in a direction orthogonal to the axis of the casing, and the abrasive mixed with water to adjust the pressure. And a high-pressure pump device that raises and ejects from the nozzle.

[0014]

According to the present invention described above, the casing cuts the earth and sand into a cylindrical shape by the blade tip provided at the tip until it reaches the obstacle. When the casing reaches the obstacle, it cuts the obstacle into a cylindrical shape as well. When the obstacle is completely cut, since the earth and sand are left in the upper part and the obstacle is left in the lower part in the casing, the earth and sand left in the casing is discharged to the surface of the earth by a known method, for example, in a hammer mag. At that time, the earth and sand filling the radial gap between the casing and the obstacle are also removed, but since the inner surface cutter is attached to the tip of the casing, it is radially between the casing and the obstacle. A gap having a size into which a nozzle described later can be inserted is formed. The kelly bar is connected to the casing along the axis of the casing, and a nozzle holder having nozzles attached to the lower side is fixed to the lower end of the kelly bar. Since the nozzle is attached to the lower part of the nozzle holder and the nozzle holder is fixed to the kelly bar, specifically, when the nozzle holder is inserted into the gap, the nozzle is inserted at a predetermined lower position from the lower end of the kelly bar.

The abrasive is mixed with water through a pump device, the pressure is increased, and the abrasive is ejected from the nozzle. This nozzle is arranged in a direction orthogonal to the axis of the casing, so that the obstacle is sliced. The sliced obstacle is easily grasped by a grab hammer or the like, lifted and discharged to the surface of the earth.

Accordingly, since the cutting position of the residual obstacle can be positioned at a predetermined position in consideration of the weight to be lifted, it is not necessary to use a rocket hammer, a chisel hammer or the like, and a further inner surface cutter can be attached. Without having to prepare casings with different diameters,
Since the construction time is shortened, vibration and noise are not generated, and the casing is not pulled out in the middle, it is possible to expect high quality piles without the entry of earth and sand.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. First, a publicly known technique will be described for better understanding of the present invention.

A known casing driver will be described with reference to FIG. The casing driver has a casing driver body 1 and a cylindrical casing 2. The casing driver body 1 is fixed on a jig iron plate 4 laid on the ground G, and the casing 2 is rotated by a rotation drive device 5 via a band device 6. An outer tooth cutter 7, an inner tooth cutter 8 and an inner surface cutter 9 are attached to a lower end portion of the casing 2 to cut the ground into a ring shape and, if there is an obstacle 10 in the ground, similarly cut into a ring shape. The obstacle 10a, which is formed in a cylindrical shape only on the peripheral surface, is left inside.

Although the above is related to the known technique,
Now, the kelly bar 3 which is a part of the constitution of the device according to the present invention.
Is a long member having a square cross section that extends movably along the axis of the casing 2, and is made to rotate together with the casing 2 by the connecting member 11. More specifically, in FIGS. 2 to 4, the connecting member 11 is provided with a square rectangular tube-shaped hole 12 in the center and integrally formed with a cross-shaped member. The end of this cross-shaped member is fixed to the upper end of the casing 2 by an angle member 13 via a bolt.

The nozzle holder 14 is fixed to the lower end portion of the kelly bar 3 of the casing driver through a bolt,
A pair of nozzles 15 is arranged at the lower end of the nozzle holder 14 so as to face each other, and is fixed in a direction orthogonal to the axis of the casing 2. In this case, the nozzle holder 14 is a cylindrical body 14b with a top plate 14a, and the top plate 14a is fixed to the kelly bar 3, and as shown in FIG. 5, a pair of nozzles 15 are arranged to face the inner surface of the cylinder body 14b. , The pipes are fixed by welding or the like. Nozzle 1
As shown in FIG. 6, in order to protect the nozzle 5, a nozzle curing iron plate 15a is fixed by welding or the like with the nozzle 15 interposed therebetween.
FIG. 7 shows the nozzle 15, the pipe 16, and the nozzle curing iron plate 15a.
The assembly 18 is formed by welding the top plate 14a on which the pipe 16 and the high-pressure water jetting device 17 are arranged to the cylindrical body 14b integrally fixed by welding.

The dimensions of the cylindrical body 15a to which the nozzle 15 and the nozzle curing iron plate 15a shown in FIG.
The inner tooth cutter 8 and the inner surface cutter 9 attached to the casing 2 are vertically rotatably and rotatably regulated in a radial gap S formed by the inner surface cutter 9, and are rotated 180 degrees alternately clockwise and counterclockwise. It is supposed to be.

The nozzle 15 is connected to a high-pressure water jetting device 17 by a pipe 16, and a high-pressure pump unit 19 and an abrasive material supply tank 20 which are arranged on the ground by a pipe 16a.
A monitoring control board 21 is provided to monitor and control the operations of the high-pressure pump unit 19 and the abrasive material supply tank 20.

Next, the operation of the above configuration will be described. The cylindrical casing 2 is rotated by a casing driver to be submerged in the ground. The presence of the obstacle 10 is predicted in advance, but the casing 2 is cut into a cylindrical shape by the cutting edge provided with the tip at the tip, that is, the outer tooth cutter 7, the inner tooth cutter 8 and the inner surface cutter 9, until the obstacle 2 reaches the obstacle 10. To do. When the casing 2 reaches the obstacle 10, the obstacle is similarly cut into a cylindrical shape to obtain the obstacle 10a (cutting step).

The fact that the casing 2 has reached the obstacle 10 is judged by a change in the number of revolutions and an increase in the amount of electric power. Now, when the obstacle is completely cut, since the earth and sand are left in the upper part and the obstacle 10a is left in the lower part in the casing 2, the earth and sand left in the casing 2 are removed to the ground surface by a known method, for example, with a hammer mag. . At that time, the earth and sand filling the radial gap S between the casing 2 and the obstacle 10a are also removed. Since the inner surface cutter is attached to the tip of the casing, the gap S is formed in such a size that a nozzle described later can be inserted between the casing and the obstacle in the radial direction (gap forming step).

Next, the kelly bar 3 is connected to the casing 2 along the axis of the casing 2 to form a cross-shaped connecting member 11.
It is connected via the (1) so that it can move up and down while being driven (kelly bar connecting step).

Next, the top plate 14a of the nozzle holder 14 to which the nozzle 15 is attached at the lower position is fixed to the lower end portion of the kelly bar 3 via a bolt (nozzle holder fixing step).

Next, the nozzle 15 is inserted into the gap S. Since the nozzle 15 is attached to the lower portion of the cylindrical body 14b of the nozzle holder 14 and the nozzle holder 14 is fixed to the lower end portion of the kelly bar 3, specifically, The cylindrical body 14b of the nozzle holder 14 is inserted into the front space S (nozzle insertion step). The insertion position can be arbitrarily set by moving the kelly bar 3 in the vertical direction.

Next, by using the monitor control board 21, the kelly bar 3
As shown in FIGS. 1 and 7, is lowered to a position having a desired thickness H from the upper surface of the obstacle 10a. The value of the thickness H differs depending on the type of the obstacle 10a. In short, it is only necessary that the hammer grip can easily grasp and lift the obstacle 10a. Next, the high-pressure pump unit 19 and the abrasive supply tank 20 are operated to supply water mixed with the abrasive to the pipe 16
a, the nozzle 1 through the high-pressure water jetting device 17 and the pipe 16
It becomes a pressure higher than 5 and ejects it, and the kelly bar 3
The nozzle holder 14 fixed to the kelly bar 3 is rotated 180 ° in the space S, and the inversion is repeated. The nozzle 15 is arranged in a direction orthogonal to the axis of the casing 2, and the high-pressure water contains an abrasive,
The obstacle 10a gradually becomes smaller in diameter 10b and is finally cut horizontally (cutting step).

The control timing of the high-pressure water injection timing and pressure, etc.
Controlled by 1. During cutting, vibration and noise are not generated because it is performed only by water injection in the ground, and the cut obstacle 1
Since 0a has an appropriate weight, it can be easily grasped and removed by a hammer mug without further crushing and cutting. Since the casing 2 is not removed during the cutting process, there is no inflow of sediment that is harmful to pile construction. The obstacle sliced in this manner is easily grasped by a grab hammer or the like, lifted and discharged to the surface of the earth.

Therefore, since residual obstacles can be sliced and the keriver can be positioned at a predetermined position, it is not necessary to use a rocket hammer, a chisel hammer, or the like, and a further inner surface cutter is not attached. Since there is no need to prepare
No noise is generated, and since the casing is not pulled out on the way, dirt does not enter.

[0031]

Since the present invention is constructed as described above, it has the following effects.

1. Since the obstacle cut into a cylindrical shape by the casing is cut in a direction orthogonal to the axis of the casing in a state where the obstacle is inserted into the casing, there is no possibility that the surrounding earth and sand enter.

2. Since it is cut by high-pressure water injection, there is no vibration or noise, and there is no pollution even when working in urban residential areas.

3. Since a gap is formed between the casing and the obstacle in the radial direction of the casing, the nozzle sprays high-pressure water toward the casing axis from this gap to cut the obstacle into an appropriate thin slice, so it can be easily removed. You can

4. Work is easy because work efficiency is improved,
As a result, high quality piles can be created.

[Brief description of drawings]

FIG. 1 is a partial sectional side view showing an underground obstacle cutting device according to the present invention.

FIG. 2 is a plan view showing an underground obstacle cutting device according to the present invention.

FIG. 3 is a diagram for explaining a connection between a casing and a kelly bar.

FIG. 4 is a view for explaining the fixing of the frame and the kelly bar.

FIG. 5 is a diagram illustrating the arrangement of nozzles.

FIG. 6 is a view for explaining the arrangement of nozzle curing iron plates.

FIG. 7 is a diagram illustrating a cutting process.

FIG. 8 is a diagram illustrating a conventional obstacle removal method.

FIG. 9 is a diagram illustrating another conventional obstacle removal method.

FIG. 10 is a diagram illustrating still another conventional obstacle removal method.

FIG. 11 is a view for explaining still another conventional obstacle removal method.

FIG. 12 is a diagram illustrating still another conventional obstacle removal method.

FIG. 13 is a diagram illustrating still another conventional obstacle removal method.

[Explanation of symbols]

 1 ... Casing driver main body 2, 2a ... Casing 3 ... Kelly bar 4 ... Jig iron plate 5 ... Rotation drive device 6 ... Band device 7 ... External tooth cutter 8 ... Internal tooth cutter 9 ... Inner surface cutter 9a ... Auxiliary inner surface cutter 10, 10a, 10c, 10d ... Obstacle 11 ... Connecting material 12 ... Hole 13 ... Angle material 14 ... Nozzle Holder 14a ... Top plate 14b ... Cylindrical body 15 ... Nozzle 15a ... Nozzle curing iron plate 16, 16a ... Piping 17 ... High pressure water jetting device 18 ... Assembly 19 ... High-pressure pump unit 20 ・ ・ ・ Abrasive material supply tank 21 ・ ・ ・ Monitor control panel 30 ・ ・ ・ Hammaglab 40 ・ ・ ・ Rocket hammer 50 ・ ・ ・ Chisel hammer H ・ ・ ・ Cutting thickness S ・ ・ ・ Gap t ・ ・・The thickness of the medium obstacle

Claims (2)

[Claims] 1. A method for cutting an underground obstacle remaining in a cylindrical casing having a cutting edge provided at its tip and drilling while rotating, in a method for cutting an underground obstacle, wherein the casing is rotated to cause earth and sand and underground obstacles. Cutting the object to form a gap in the radial direction of the casing with the underground obstacle, removing the sand in the casing, connecting the kelly bar to the casing axis, and installing the nozzle A step of fixing the nozzle holder to the kelly bar, a step of inserting a nozzle into the gap, and a high-pressure water mixed with abrasive from the nozzle in a direction orthogonal to the axis of the casing while rotating about the axis of the casing. And a step of cutting the underground obstacle in a direction perpendicular to the axis line. 2. An underground obstacle cutting device for cutting an underground obstacle remaining in a cylindrical casing having a cutting edge provided at the distal end and drilling while rotating, the radial direction being attached to the distal end of the casing. Between the casing and the underground obstacle, which is fixed to the inner cutter that forms a gap between the casing and the underground obstacle, and is fixed to the kelly bar that is attached after the underground obstacle is cut into a cylindrical shape by the casing. A nozzle holder inserted into the gap of
A nozzle mounted below the nozzle holder and arranged in a direction orthogonal to the axis of the casing; and a high-pressure pump device that mixes an abrasive with water to increase the pressure and eject from the nozzle. Underground obstacle cutting device.