JPH08270355A - Double-pipe type drilling bit - Google Patents

Abstract

PURPOSE: To prevent muddy-water-containing cuttings and underground water from flowing back into a drilling pipe at the end of a drilling operation, during the work of extending the drilling pipe, by enabling the efficiency of the drilling operation to be increased, and enabling muddy-water-containing cuttings generated by the drilling to be conveyed out through the pipe. CONSTITUTION: This double-pipe type drilling bit has a cylindrical ring bit body 22 provided at the drilling end of a drilling pipe 20; a Kronen bit body 25 having a clutch connection and provided inside the ring bit body 22; and an inner rod body 45 having a water passage 46b through which drilling pressure water is supplied, having also a clutch connection for connection to the former clutch connection, and passed through the drilling pipe to transmit power to the Kronen bit body 25 by means of a clutch lock. The Kronen bit body 25 has a communicating passage 26a communicated with the water passage 46b, and a spout 31 from which the pressure water is injected back into a drill hole is formed at the drilling end of the Kronen bit body 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double pipe type drilling bit capable of carrying cutting waste containing mud generated by excavation through a pipe to the outside.

[0002]

2. Description of the Related Art Conventionally, as an excavation system for excavating soft ground, a ring bit screwed to the excavation tip of a single pipe type excavation pipe and a Kronen bit connected to the ring bit via a shear pin are used. It is known to use a drilling bit that has. A water passage communicating with the excavation pipe is provided at the tip of the Kronen bit.
94189).

FIG. 18 shows an example of the excavation system and is an explanatory view of excavation work in the reservoir construction. In FIG. L is the ground surface, and U. L is the pond, V.
W is an impermeable wall, 1 is an excavation pipe as a drilling bit component, 2 is a Kronen bit, 3 is a venter, 4 is a swivel as an excavation pipe driving device, 5 is a water pump, 6
Is a seal member.

In this conventional excavation system, the excavation pipe 1 is rotationally driven, the excavation pipe 1 is pressed in the excavation advancing direction by the swivel 4, and the water pump 5 supplies the pressurized water into the excavation pipe 1 to supply the Kronen bit. 2 is discharged and jetted, and the cutting waste containing muddy water is carried out toward the wellhead 12 from the gap 11 of the drilling hole formed between the drilling pipe 1 and the well wall 10. The cutting waste containing the muddy water carried to the mine mouth 12 is discharged to the outside via the preventer 3.

In this excavation system, when the excavation progresses to the planned depth, the excavation pipe 1 is slightly pulled up, the anchor wire is inserted into the excavation pipe 1, and the cement is injected into the excavation pipe 1, while the excavation pipe 1 is inserted. I try to remove it from the drill hole. In addition, the pond bottom U. L is dug deeper as the construction progresses.

[0006]

However, in the conventional excavation system for excavating the soft ground, excessive groundwater pressure is exerted on the well wall 10 of the excavation hole, especially in the excavation work in the area having the flood layer. , Drill pipe 1 and pit wall 10
Since the debris containing muddy water is carried out toward the wellhead 12 by so-called outturning from the gap 11 of the excavation hole formed between and, the collapse of the mine wall 10 due to the flow of muddy water easily occurs, which causes ground subsidence and ground There is a possibility of inducing a water fountain or a water fountain to the wellhead 12, and the excavation work is generally difficult, and it is desired to improve the efficiency of the excavation work.

The present invention has been made in view of the above circumstances, and a first object thereof is to provide a double pipe type drilling bit capable of promoting the efficiency of excavation work by simultaneously driving the inner and outer bits. To do.

A second object of the invention is to provide a double pipe type drilling bit which can carry out cutting wastes containing mud water generated by excavation through the pipe to the outside.

A third object thereof is to provide a double pipe type drilling bit capable of preventing backflow of cutting waste containing muddy water and groundwater in the excavation pipe at the time of adding the excavation pipe and at the end of excavation. Especially.

[0010]

In order to achieve each of the above objects, a double pipe type drilling bit according to claim 1 of the present invention is provided with a cylindrical ring bit body provided at the excavation tip of an excavation pipe. A clutch connection part having a clutch connection part and provided in the ring bit body, a water passage for supplying pressurized water for excavation, and a clutch connection part corresponding to and connected to the clutch connection part. And an inner rod body that is inserted into the excavation pipe and transmits power to the Kronen bit body by a clutch lock. The Kronen bit body has a communication passage that communicates with the water passage. A discharge port for discharging the pressurized water toward the excavation hole is formed at the excavation tip of the bit body, and excavation can be performed by translational movement of the ring bit body and the Kronen bit body. The features.

Preferably, the Kronen bit body is coupled to the ring bit body via a shear pin, and the shear pin is cut by relative movement of the inner rod with respect to the ring bit body in a pipe axis direction, The bit body is left buried in the bottom of the drill hole.

Further, preferably, the Kronen bit body is connected to the ring bit body via the movable bit body having a blade portion at the tip of excavation and movable in the pipe axis direction during excavation and the shear pin. It is composed of
The movable bit body is formed with the communication passage and the discharge port, and a gap between the water blocking cylinder and the movable bit body serves as a discharge passage for cutting waste containing muddy water during excavation.

Further, after cutting the shear pin, in order to prevent the debris containing muddy water from flowing back to the ring bit body through the hole formed at the shear pin installation location of the ring bit body, the crownen bit is provided. The body has an O-ring seal.

More preferably, in order to prevent the cutting waste containing the muddy water and the groundwater from flowing back to the carry-out path at the time of non-excavation before cutting the shearing pin, the movable bit body is provided on the rear end side of the excavation tip. A seal portion is provided to seal the tip of the water shielding cylinder, and the movable bit body is provided with a valve portion opened in the communication passage by pressurized water for excavation.

[0015]

According to the double pipe type drilling bit according to the present invention, excavation is performed by the translational motion of the cylindrical ring bit body and the Kronen bit body. During the excavation, the pressurized water for excavation is supplied through the water passage of the inner rod body and the communication passage of the Kronen bit body, and the compressed water is excavated from the discharge port of the excavation tip of the Kronen bit body. It is jetted backward so as to suck the muddy water from the hole. Dust containing muddy water generated during excavation is carried out to the outside through the gap between the ring bit body and the Kronen bit body. The gap between the ring bit body and the Kronen bit body is closed at the time of replenishment work of the excavation pipe, etc., so that the cutting waste containing mud generated during the excavation is prevented from entering the excavation pipe. In addition, since the valve portion is provided in the communication passage of the Kronen bit body and this valve portion is closed when the supply of the pressurized water is stopped, the cutting waste containing the muddy water generated during the excavation enters through the communication passage. It is also prevented. After completion of excavation, the chronane bit body is separated from the ring bit body and left at the bottom of the excavation hole.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a cross-sectional view of a double pipe type drilling bit according to the present invention on the excavating tip side, and FIG. 2 shows a cross sectional view of a double pipe type drilling bit on the rear end side of excavating. ing.

In FIG. 1, 20 is a first excavation pipe. A screw portion 20a is formed on the inner periphery of the first excavation pipe 20 on the excavation tip side, and a screw portion 20b is formed on the outer periphery thereof on the excavation rear end side. The second excavation pipe 21, the third excavation pipe, ... Are successively added to the first excavation pipe 20 as the excavation hole extends, and the second excavation pipe 21 is shown by a two-dot chain line in FIG. ing. This second drill pipe 2
A threaded portion 21a that is screwed into the threaded portion 20b is formed on the inner periphery on the tip side of 1, and a threaded portion (not shown) is formed on the outer periphery on the rear end side of the second excavation pipe 21. A tubular ring bit body 22 is provided on the excavation tip side of the first excavation pipe 20. At the excavation tip of the ring bit body 22, ten mounting recesses are formed at equal angles, and a hard drilling blade 23 is fixed to the mounting recess as shown in FIG. On the rear end side of the ring bit body 22, the screw portion 2
2a is formed on the outer periphery thereof, and this screw portion 22a is screwed to the screw portion 20a of the first excavation pipe 20 as shown in FIG. An elliptical insertion hole for inserting the shear pin 24 is formed in the peripheral wall of the axial direction intermediate portion of the ring bit body 22. The shear pins 24 are a pair of two and are arranged so as to face each other. The role of the shear pin 24 will be described later.

A Kronen bit body 25 is provided in the ring bit body 22. This Kronen bit body 25 is, here, the movable bit body 26 and the water blocking cylinder 2.
7 and 7. The movable bit body 26 has an excavation blade member 28 fixed to the excavation tip by screws 29.
The digging blade member 28 is fixed with the digging blade 30 every 120 degrees as shown by the chain double-dashed line in FIG. The excavating blade member 28
The discharge holes 31 are provided at intervals of 120 degrees between the circumferential cutting blades.
Are formed. Further, a tapered surface 28a is formed at the rear end portion of the excavating blade member 28.
An O-ring seal 32 is provided at a. The roles of the tapered surface 28a and the O-ring seal 32 will also be described later.

The movable bit body 26 has a communication passage 26a extending in the axial direction. A passage 26b communicating with the discharge port 31 is provided on the excavation tip side of the communication passage 26a so as to correspond to each discharge port 31. At the rear end side of the movable bit body 26, the communication path 2
A spring receiving portion 26c is provided on the inner wall of 6a, and an annular valve seat member 33 forming a part of the valve portion is provided. The valve seat member 33 connects the compression spring 34 to the communication passage 2
6a, the ball valve 35 is inserted into the communication passage 26a, and then fixed to the inner peripheral wall of the communication passage on the rear end side of the movable bit body 26 by means such as welding. The compression spring 34 urges the ball valve 35 in the direction of closing the communication passage 26a.
At the rear end of the movable bit body 26, engaging recesses 26d as clutch coupling portions for clutching with an inner rod body, which will be described later, are formed every 90 degrees as shown in FIG.

The drilling bit according to the present invention has a double pipe structure composed of a ring bit body 22 and a water blocking cylinder 27. A valve collar member 36 is provided in the water shielding cylinder 27. The valve collar member 36 is composed of an outer cylinder 36a, an inner cylinder 36b, and a connecting wall 36c, and the outer cylinder 36a is welded and fixed to a step portion on the excavation tip side of the water blocking cylinder 27. The inner cylinder 36b serves as a guide for the movable bit body 26. A taper portion 37 is formed on the excavation tip side of the water blocking cylinder 27, and a pair of elliptical insertion holes 24a through which the shear pin 24 is inserted are formed in the taper portion 37 as shown by 6. The water blocking cylinder 27 and the ring bit body 22 are connected to each other via. O-ring seals 38 and 39 are provided on both sides in the axial direction with the shear pin 24 sandwiched between them on the outer peripheral wall of the water-blocking tubular body 27. A taper surface 37 a is formed on the taper portion 37 on the side facing the rear end of the excavating blade member 28.
The inclination angle of a is substantially the same as the inclination angle of the tapered surface 28a.

The movable bit body 26 is axially movable with respect to the water-blocking cylinder 27, and an annular step portion 26e for receiving a spring is formed on the outer periphery of the movable bit body 26, so that the valve collar member 36 has the same shape. A compression spring 40 is interposed between the rear end of the inner cylinder 36a and the annular step 26e. The compression spring 40 plays a role of urging the movable bit body 26 in the direction of the wellhead, and the tapered surface 28 a of the excavating blade member 28.
The movement of the movable bit body 26 in the direction of the pit is stopped by the abutment between the movable bit body 26 and the taper surface 37a of the water blocking cylinder 27. There is a gap 41 between the movable bit body 26 and the water blocking cylinder 27, and the tip end side of this gap 41 in the excavation direction is closed as shown in the upper half of FIG. During excavation, it is opened as shown in the lower half of FIG. This gap 4
The role of 1 will be described together with the operation of the present invention.

A guide cylinder 42 for guiding the rear end of the movable bit body 26 is provided on the rear end side of the water shielding cylinder 27. The guide cylinder 42 is fixed to the rear end of the water blocking cylinder 27 by welding the bracket 43 shown in FIG.
The O-ring seals 44, 44 are provided on the outer peripheral wall of the water blocking cylinder 27 at a position corresponding to the intermediate portion in the axial direction and the rear end of the ring bit body 22 and the rear end of the water blocking cylinder 27. 'Is provided. The role of the O-ring seals 44 and 44 'will be described together with the function of the present invention.

An inner rod assembly 45 is inserted into the first excavation pipe 20, the second excavation pipe 21 ,. As shown in FIG. 2, the inner rod assembly 45 is composed of a first inner rod 46, a second inner rod 47, a third inner rod, .... An engaging projection 46a that is engaged with the engaging recess 26d of the movable bit body 26 by a clutch is formed at the tip of the first inner rod 46, as shown in FIGS. 1, 8 and 9. A through hole 46b extending in the axial direction is formed in the first inner rod 46 as a water passage for supplying pressurized water for excavation. A threaded portion 46c is formed on the outer periphery of the rear end of the first inner rod 46. The screw portion 46c has a second inner rod 47 shown in FIG.
The threaded portion 47a formed on the inner circumference of the tip end side is screwed.
Further, an annular step portion 46d is formed on the outer periphery of the first inner rod 46 at an axially intermediate portion thereof.
6d is brought into contact with the guide cylinder 42 of the water-blocking cylinder 27 when the shear pin is cut.

A threaded portion 47b is formed on the outer periphery of the rear end of the second inner rod 47, and a third inner rod, ... Is successively added to the threaded portion 47b as the excavation hole extends. The second inner rod 47,
A through hole as a water passage is formed in the third inner rod, ..., In FIG. 2, reference numeral 47c indicates the through hole. On the peripheral wall of the through hole 46b of the first inner rod 46, as shown in FIG.
Are formed. An annular valve seat member 48 is provided on the peripheral wall of the through hole 46b on the rear end side of the annular step portion 46d. The valve seat member 48 is fixed to the peripheral wall of the through hole on the rear end side of the first inner rod 46 by means such as welding after inserting the compression spring 49 into the communication passage 46b and inserting the ball valve 50 into the communication passage 46b. It The compression spring 49 moves its ball valve 50 in the direction of closing the through hole 46b.
Energize. A guide member 51 is provided at the boundary between the first inner rod 46 and the second inner rod 47. As shown in FIG. 9, the guide member 51 has a base portion welded to the first inner rod 46 and the second inner rod 47. The guide member 51 is provided at every 90 degrees in the circumferential direction of the first inner rod 46, as shown in FIG.
It is in sliding contact with the inner wall of the excavation pipe 21). As shown in FIGS. 9 and 10, a gap 52 is formed between the drill pipe and the inner rod body 45. The gap 52 is shown in FIGS.
2 leads to the gap 41.

The excavation tip side opening 53 of the ring bit body 22
(See FIGS. 9 and 13) is communicated with the gap 41 during excavation. Before excavation, as shown in FIG. 9, the clutch lock between the Kronen bit body 25 and the inner rod body 45 is released. The opening 53 on the tip end side of the excavation and the gap 41 form the tapered surface 28a of the excavation blade member 28 and the water shielding cylinder 27.
The taper surface 37a and the O-ring seal 32 are disconnected from each other.

At the time of excavation, as shown in FIG. 14, the inner rod body 45 is advanced in the excavation direction and is clutch-connected to the Kronen bit body 25, and the Kronen bit body 2 is engaged.
5 is advanced toward the bottom of the drill hole against the biasing force of the compression spring 40. Then, when pressurized water is supplied to the water passage of the inner rod body 45 by a water pump (not shown),
The ball valve 50 is opened, and the ball valve 35 of the chronane bit body 25 is opened. The pressure water is the discharge port 3
1 is injected into the drill hole. At the same time, the excavation pipe is rotated by an unillustrated swivel, and power is transmitted to the Kronen bit body 25 through the inner rod body 45, and the Kronen bit body 25 is rotationally driven. As a result, the ring bit body 22 and the Kronen bit body 25 are separately translated and excavated, and the cutting waste is carried out by pressure water injection. The debris containing muddy water generated by the excavation is discharged from the wellhead through the opening 53 and the gaps 41 and 52, and the gap 41 between the water blocking cylinder 27 and the movable bit body 26 collects the muddy water during the excavation. It serves as a discharge route for excavated waste. In this way, since the debris containing mud is carried out from the pit through the inside of the drill pipe to the outside, collapse of the pit wall due to the flow of mud, ground subsidence resulting from this, fountain to the ground, You can avoid triggering a fountain. When the drill pipe is replenished, the water supply by the water pump is stopped, and the inner rod body 45 is moved in the direction of the wellhead with respect to the drill pipe, and the clutch lock between the Kronen bit body 25 and the inner rod body 45 is released. To be done. Then, the movable bit body 26 is retracted by the urging force of the compression spring 40, the tapered surface 28a of the excavating blade member 28 abuts the tapered surface 37a of the water-blocking tubular body 27, and the excavation tip gap 41 becomes the O-ring seal. Since it is sealed by 32, when excavating pipes and inner rod bodies are replenished, cuttings containing muddy water and groundwater flow back into the gap 41 and are prevented from ejecting from the wellhead. Further, the ball valve 35 is moved in the valve closing direction by the urging force of the compression spring 34, and the communication passage 26a and the through hole 4
The communication with 6b is cut off. Similarly, the ball valve 50 is moved in the valve closing direction, and the through hole 46b and the through hole 47c are also blocked. Therefore, through the discharge port 31, the communication passage 26a, and the water passage of the inner rod body 45, cuttings containing muddy water,
Backflow of groundwater is also prevented.

When the excavation progresses to the planned depth, the water supply by the water supply pump is stopped. Due to the stop of the water supply, the communication paths 26a and the through holes 46b are closed by the ball valves 35 and 50 as described above. And the inner rod body 4
When 5 is moved in the direction of the bottom of the excavation hole relative to the excavation pipe, the tip of the movable bit body 26 projects from the opening 53, as shown in FIG. At that time, the compression spring 40 is further compressed as compared with that at the time of excavation. This Figure 15 shows Sharpin 2
4 shows the state immediately before cutting of No. 4, and the annular step portion 46d of the first inner rod 46 is in a position where it contacts the guide cylinder 42 of the water-blocking cylinder 27 or not. Further, when the inner rod body 45 is moved in the direction of the bottom of the excavation hole relative to the excavation pipe, the shear pin 24 is cut, and the water shielding cylinder 27 and the ring bit body 22, as shown in FIG. Is cut off, and the water blocking cylinder 27 projects together with the movable bit body 26 from the opening 53 of the ring bit body 22 toward the bottom of the excavation hole. That is, the connection between the Kronen bit body 25 and the ring bit body 22 by the shear pin 24 is broken. The O-ring seal 44 ′ of the water-blocking tubular body 27 plays a role of preventing backflow of the cutting waste containing mud and groundwater into the ring bit body 22 through the hole at the shear pin installation location of the ring bit body 22. After the shear pin is cut, the ring bit body 22 is located on the rear side of the shear pin cut portion. The O-ring seal 44 is provided auxiliary.

When the inner rod body 45 is pulled out from the excavating pipe, the movable bit body 26 is retracted by the urging force of the compression spring 40, and collides with the taper surface 37a of the water shielding cylinder 27 and the taper surface 28a of the excavating blade member 28. Then, the O-ring seal 32 closes the gap 41. 15 to 17
The series of operations shown up to are performed in a short time. Therefore, during the shearing-pin cutting operation, it is possible to prevent the debris and groundwater containing muddy water from flowing back into the ring bit body 22 through the gap 41. Since the communication passage 26a is closed by the ball valve 35 before the shear pin is cut, it is also prevented that the cutting waste containing the muddy water and the ground water flow into the excavation pipe through the discharge port 31 and the communication passage 26a.

In the state shown in FIG. 17, cement milk is injected into the excavation pipe, the Kronen bit body 25 is integrated with the cement and left at the bottom of the excavation hole. On the other hand, the ring bit body 22 is removed together with the drill pipe from the drill hole while injecting cement toward the bottom of the drill hole.

[0030]

As described above, in the double pipe type drilling bit according to the present invention, since the ring bit body and the Kronen bit body are driven to rotate separately, the efficiency of excavation work is promoted. There is an effect that can be. In addition, it is possible to carry out the debris containing mud generated by excavation to the outside through the pipe, and prevent the debris containing mud and groundwater from flowing back into the excavation pipe at the time of refilling the excavation pipe and at the end of excavation. There is an effect that can be.

[Brief description of drawings]

FIG. 1 shows a cross-sectional view of a double pipe drilling bit according to the present invention on a tip side of excavation.

FIG. 2 shows a cross-sectional view of the double pipe drilling bit according to the present invention on the rear end side of excavation.

FIG. 3 is a plan view showing a shape of a drilling tip of a ring bit body according to the present invention.

FIG. 4 is a plan view showing the shape of a digging tip of the Kronen bit body according to the present invention.

FIG. 5 is a plan view showing the shape of the excavation tip of the Kronen bit body according to the present invention.

FIG. 6 is a plan view showing the shape of the excavation-side tip of the water blocking cylinder according to the present invention.

FIG. 7 is a plan view showing the shape of the rear end of the water blocking cylinder according to the present invention.

FIG. 8 is a plan view showing the shape of the tip of the inner rod body according to the present invention.

FIG. 9 is a vertical cross-sectional view showing a state before excavation of the double pipe drilling bit according to the present invention, which is partially simplified.

10 is a cross-sectional view taken along the line AA of FIG.

11 is a cross-sectional view taken along the line BB of FIG.

12 is a cross-sectional view taken along the line CC of FIG.

13 is a plan view of the double pipe type drilling bit of FIG. 9 viewed from the excavation tip side.

FIG. 14 is a vertical cross-sectional view showing a state of the double-pipe drilling bit according to the present invention during excavation, which is partially simplified.

FIG. 15 is a longitudinal sectional view showing a state immediately before cutting of the shear pin of the double-tube drilling bit according to the present invention, which is partially simplified.

FIG. 16 is a vertical cross-sectional view showing a state after cutting the shear pin of the double-tube drilling bit according to the present invention, which is partially simplified.

FIG. 17 is a vertical cross-sectional view showing a state of the double-pipe type drilling bit according to the present invention when cement milk is injected, which is partially simplified.

FIG. 18 is an explanatory diagram showing an example of a conventional excavation system.

[Explanation of symbols]

 20 ... 1st excavation pipe 21 ... 2nd excavation pipe 22 ... Ring bit body 24 ... Shear pin 25 ... Kronen bit body 26 ... Movable bit body 26a ... Communication passage 27 ... Impermeable cylinder 31 ... Discharge port 41 ... Gap 44 '... O-ring seal 45 ... Inner rod body 46b, 47c ... Through hole (water passage)

Claims (6)

[Claims] 1. A cylindrical ring bit body provided at a digging tip portion of a digging pipe, a Kronen bit body provided in the ring bit body with a clutch coupling portion, and pressurized water for digging. An inner rod body that has a water passage and has a clutch coupling portion that corresponds to the clutch coupling portion and that is coupled to the clutch coupling portion, and that is inserted into the excavation pipe and that transmits power to the Kronen bit body by a clutch lock; The Kronen bit body has a communication passage that communicates with the water passage, and a discharge port for reversely injecting the pressurized water toward the drill hole is formed at the excavation tip end portion of the Kronen bit body, and the ring bit. A double-pipe drilling bit characterized by excavating by a translational motion between a body and the Kronen bit body. 2. The Kronen bit is joined to the ring bit body via a shear pin, and the shear pin is cut by relative movement of the inner rod with respect to the ring bit body in a pipe axis direction. The double-pipe drilling bit according to claim 1, wherein the body is left buried in the bottom of the drill hole. 3. The water shield connected to the ring bit body via the movable bit body, which has an excavation blade at the excavation tip and is movable in the pipe axis direction during excavation, and the shear pin. The movable bit body is provided with the communication passage and the discharge port, and the gap between the water blocking cylinder and the movable bit body contains muddy water during excavation. 3. The discharge path of claim 2
Double tube drilling bit described in. 4. In order to prevent the cutting waste containing muddy water from flowing back to the ring bit body through a hole formed at the shear pin installation location of the ring bit body after cutting the shear pin, the kronen The double-tube drilling bit according to claim 3, wherein the bit body is provided with an O-ring seal. 5. The movable bit body is provided with the shield on the rear end side of the excavation tip in order to prevent the cutting waste containing muddy water and the groundwater from flowing back to the carry-out path at the time of non-excavation before cutting the shear pin. The double pipe drilling bit according to claim 4, further comprising a seal portion that seals a tip of the water cylinder. 6. The double-pipe drilling bit according to claim 5, wherein the movable bit body is provided with a valve portion opened in the communication passage by pressurized water for excavation.