JPH07166545A - Drilling device - Google Patents

Abstract

PURPOSE:To improve the execution property by providing a ball valve, a slide tube and the like in a drilling bit, connecting the drilling bit and a drive shoe with a ball key, and separating the bit when a casing tube is extracted. CONSTITUTION:A drilling bit 17 provided with a ball valve 29 excited by springs 27, 33 and a slide tube 35 is connected to a drive shoe 13 connected to a casing tube via a ball key 53. Water is ejected from a jet hole to excavate the ground 45, and an earth anchor hole 47 is formed. When water feed is stopped, the ball valve 29 is closed to prevent the back flow of slurry, and a ball 49 is inserted to block a valve seat 43. An anchor cable is inserted, a grout material is injected by pressure, the slide tube 35 is pressed down, the ball key 53 is released, and the coupling between the drive shoe 13 and the drilling bit 17 is released. When the casing tube is extracted, the drilling bit 17 is left in the hole 47. The execution of an earth anchor can be efficiently performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a drilling device used for construction of an earth anchor.

[0002]

2. Description of the Related Art Conventionally, the earth anchor construction method has been widely used for the purpose of preventing falls of retaining walls and bridge piers, buoyancy of dock floor boards, and ground slip.

In this earth anchor construction method, water for drilling is poured into a casing pipe connected to a drilling machine, and the ground is drilled with a drilling bit at the tip of the casing pipe, and an anchor cable (steel) is drilled in the drilled anchor hole. After inserting the wire, pull out the casing pipe and pressurize the grout material into the anchor hole to create an anchor body in the ground to connect the ground and the structure. The casing pipes are sequentially connected according to the drilling depth.

Thus, conventionally, when constructing an earth anchor on soft ground, a Kronen bit incorporating a check valve inside is used as a drilling bit. As shown in FIG. 6, the Kronen bit 1 is attached to the casing tube 3 via a drive shoe 5 screwed to the insertion side end of the casing tube 3, and is inserted into the drive shoe 5 with a cylindrical portion 1 a and a drive. It is composed of a head 1b arranged at the tip of the shoe 5. Then, the cylindrical portion 1a is inserted into the drive shoe 5, and the cutout portion 7 provided at the rear end of the head portion 1b is inserted.
Is engaged with the notch 9 at the tip of the drive shoe 5 in the axial direction (drilling direction) and connected to the drive shoe 5, whereby the rotation of the casing pipe 3 is transmitted to the Kronen bit 1.

When the casing pipe 3 is pulled out by injecting the grout material, the Kronen bit 1 is separated from the drive shoe 5 and is left in the anchor hole, and is buried by the grout material. There is. In the figure,
Reference numeral 11 is a jetting water ejection hole.

[0006]

As described above, conventionally, the Kronen bit 1 is connected to the drive shoe 5 by meshing with it in the axial direction at the time of construction of the earth anchor, and is also used for pulling out the casing pipe 3. Along with this, the drive shoe 3 is separated.

However, in the case of hitting a hard rock, for example, when drilling the ground, it is necessary to carry out the flushing operation of the casing pipe 3 to proceed with the digging, and the conventional Kronen bit 1 and the drive shoe 5 as described above. In the connection structure of, the flushing operation causes the Kronen bit 1 to separate from the drive shoe 5,
Also, remove the Kronen bit 1 once, and drive shoe 5
Since it is difficult to connect to the disk, the connection structure of the Kronen bit and the drive shoe capable of flushing operation has been desired.

The present invention has been devised in view of the above circumstances, and it is possible to perform the flushing operation of the casing pipe when the anchor hole is drilled, and to separate the drill bit and the drive shoe when the casing pipe is pulled out. An object of the present invention is to provide a drilling device for earth anchor construction that can be easily performed.

[0009]

In order to achieve such an object, a boring device according to the present invention is screwed to the tip of a casing pipe connected to a boring machine, and an engaging groove is formed on the inner circumference thereof. Drive shoe, the drill bit that meshes with the drive shoe in the axial direction and is connected to the tip of the drive shoe, and is left in the anchor hole by being separated from the drive shoe when the casing tube is pulled out. It consists of steel balls that are dropped from the ground into the casing pipe prior to pouring, and the boring bit has a jetting water ejection hole formed in its head and a tubular part that is inserted into the drive shoe. , A check valve and a slide tube having a valve seat that holds the dropped steel balls that are urged toward the rear end side of the tubular portion by a spring, Bolki The mounting hole is pushed outward from the peripheral wall of the cylindrical portion by the slide tube to engage with the engagement groove of the drive shoe, and the engagement of the engagement groove with the engagement of the slide tube against the spring force of the spring. It is equipped with a ball key that is released from the rear end of the slide tube and falls into the slide tube from the rear end.

[0010]

According to the boring device of the present invention, the drive shoe and the boring bit are connected by meshing the boring bit with the drive shoe in the axial direction and engaging the ball key with the engaging groove. It will be.

Therefore, if the drive shoe having the drill bit thus connected is screwed to the tip of the casing pipe and the drilling water is fed into the casing pipe, the ground is drilled.
Anchor holes will be drilled in the ground.

Even when the casing pipe is flushed during drilling, the drill bit does not come off the drive shoe because the ball key is engaged with the engaging groove. Further, the drilling water is jetted into the ground through the jet holes of the drilling bit, but when the water supply is stopped, the check valve prevents the backflow of muddy water into the drilling bit.

When the steel balls are dropped into the casing pipe from the ground after completion of the drilling, the steel balls reach the valve seat of the slide pipe and close the water supply passage. After that,
When the anchor cable is inserted into the anchor hole and the grout material is injected under pressure, the water supply passage of the valve seat is blocked by the steel ball, so the grout material accumulates in the drive shoe and the pressure inside the drive shoe rises. As a result, the slide tube moves downward against the spring force of the spring, the ball keys in each ball key mounting hole become free and fall from the rear end of the slide tube into the slide tube, and the engaging groove Is disengaged.

Therefore, if the grout material is continuously injected in this state and the casing pipe is pulled out, the drill bit is separated from the drive shoe and remains in the anchor hole, and is buried in the anchor hole by the grout material. The Rukoto.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a hole drilling device according to an embodiment of the present invention. In the figure, 13 is a drive shoe screwed to the tip of a casing tube as in the conventional case, and one drive shoe is provided on the inner periphery thereof. An engagement groove 15 is provided. And at the tip,
The drill bit 17 is mounted so as to mesh with the drive shoe 13 in the axial direction.

The drill bit 17 comprises a head portion 17a arranged at the tip of the drive shoe 13 and a cylindrical portion 17b inserted into the drive shoe 13, and the head portion 17
A plurality of jet holes 19 for drilling water are provided in a.

In the tubular portion 17b, first, a check valve 21 similar to the conventional one is mounted on the back side of the head portion 17a. In the figure, 23 is a valve seat provided with a water supply passage 25 that expands downwardly in a tapered shape, and the valve seat 23 is fixed to the inner periphery of the tubular portion 17b. Then, as shown by the chain double-dashed line, the ball valve 29 abuts the valve seat 23 by being urged by the spring 27 stretched between the head 17a and the back surface of the head 17a to close the water supply passage 25, and the casing When the drilling water is injected into the pipe, as shown by the solid line, the water pressure causes the ball valve 29 to move downward against the spring force of the spring 27, so that the water supply passage 25 is opened. still,
In the figure, 31 is a holding member for the spring 27 and the ball valve 29.

A slide tube 35 is arranged above the check valve 21 via a spring 33. The slide tube 35 has an opening on the rear end side and is formed to have an outer diameter substantially the same as the inner diameter of the cylindrical portion 17b. Further, a recess 37 into which the spring 33 is fitted is provided at the tip thereof, and a water supply hole 39 for drilling water is formed in the center of the recess 37. A valve seat 43 having a water supply passage 41 that expands upward in a tapered shape is attached to the peripheral edge of the rear end of the slide pipe 35, and the anchor hole 47 is formed after the drilling of the ground 45 is completed. When the steel balls are thrown in from the ground when pouring the grout material into the inside, the steel balls 49 are held by the valve seat 43 and the water supply passage 41 is closed by the steel balls 49 as shown in FIG. It has become so.

On the other hand, on the peripheral wall of the cylindrical portion 17b, a plurality of ball key mounting holes 51 are provided at predetermined intervals in the peripheral direction. Then, in each ball key mounting hole 51, a ball key 53, which is pressed outward from the peripheral wall of the cylindrical portion 17b by the slide tube 35 and engages with the engaging groove 15 as shown in FIG. 1, is mounted. By engaging the ball key 53 with the engaging groove 15 in this way, the drive shoe 13 and the drill bit 17 are connected, and the ground 4
Even if the casing pipe is flushed during the drilling of No. 5, the drill bit 17 does not come off from the drive shoe 13.

The ball key mounting hole 51 has a cylindrical portion 17
An inclined portion 51a is provided inward of b, and a diameter of the inclined portion 51a which opens to the outer periphery of the cylindrical portion 17b is equal to that of the ball key 53.
It is set smaller than the diameter of. Further, as shown in FIG. 1, the rear end 17b 'of the tubular portion 17b is formed in a tapered shape so that the steel ball 49 dropped from the ground is reliably guided to the water supply passage 41 of the valve seat 43. ing.

After the water supply passage 41 is closed by the steel balls 49 as described above, when the pressure inside the drive shoe 13 is increased by the injected grout material as described later, the slide pipe 35 is provided as shown in FIG. Spring 33
When the slide pipe 35 comes into contact with the valve seat 23, the ball keys 53 in the ball key mounting holes 51 become free and slide as shown in FIG. From the rear end of the pipe 35, the slide pipe 35 (valve seat 4
3) It falls into the inside and the engagement with the engagement groove 15 is released.

Therefore, when the casing pipe is pulled out in this state, the drill bit 17 is separated from the drive shoe 13 and is left in the anchor hole 47 as shown in FIG. In addition, 55 in FIG. 1 is similar to the conventional example shown in FIG.
A notch portion formed at the rear end of the head portion 17a of the drill bit 17 and a notch portion 57 formed at the tip of the drive shoe 13. Both notch portions 55 and 57 are axially (drilling direction). The rotation of the casing pipe is transmitted to the drill bit 17 by engaging with.

Since the drilling device 59 according to the present embodiment is constructed in this way, in order to construct an earth anchor using the drilling device 59, as shown in FIG. The notch 55 of the drive shoe 13 and the notch 57 of the drive shoe 13 are axially engaged with each other, and the ball key 5
3 is mounted in the ball key mounting hole 51, the slide tube 35 is inserted into the drill bit 17 from the rear end side of the drive shoe 13, and the ball key 53 is engaged with the engagement groove 15. The drive shoe 13 and the drill bit 17 are now connected.

Then, the drive shoe 13 is screwed to the tip of the casing pipe connected to the drilling machine to feed the drilling water into the casing pipe. It suffices to sequentially connect the holes to drill the ground 45. At this time, even if the casing pipe is flushed, the ball key 53 is engaged with the engaging groove 15, so that the drill bit 17 is driven. It does not come off from the shoe 13.

Further, the drilling water is jetted into the ground 45 from the jet holes 19 of the drill bit 17, but when the water supply is stopped,
Ball valve 2 by ground water pressure and spring force of spring 27
9 blocks the water supply passage 25 of the valve seat 23, and the drill bit 17
It will prevent the backflow of muddy water.

When the steel balls 49 are dropped into the casing pipe from the ground after the boring is completed, the dropped steel balls 49 reach the valve seat 43 and close the water supply passage 41 as shown in FIG.

After that, when the anchor cable is inserted into the anchor hole 47 and the grout material G is injected under pressure, the water supply passage 41 of the valve seat 43 is blocked by the steel ball 49, so that the drive shoe 13 is closed. The grout material G accumulates and the pressure in the drive shoe 13 rises. As a result, as shown in FIG.
Moves downward against the spring force of each ball key mounting hole 5
The ball key 53 in 1 becomes free and falls from the rear end of the slide tube 35 into the slide tube 35 (valve seat 43) as shown in FIG. 4, and the engagement with the engagement groove 15 is released.

Therefore, if the grout material G is continuously injected in this state and the casing pipe is pulled out, the drill bit 17 is separated from the drive shoe 13 and remains in the anchor hole 47 as shown in FIG. Then, it is buried in the anchor hole 47 by the grout material G.

As described above, the drilling device 59 according to this embodiment.
When the ground 45 is drilled, the ball key 53 is engaged with the engaging groove 15 to connect the drive shoe 13 and the drill bit 17 and the engagement is released when the casing pipe is pulled out. By using the light boring device 59 for construction of the earth anchor, the flushing operation of the casing pipe can be performed at the time of boring, and the boring bit 17 and the drive shoe 13 can be easily separated when the casing pipe is pulled out. As a result, the workability of the earth anchor has improved dramatically compared to the conventional one.

[0030]

As described above, by using the hole drilling device according to the present invention for constructing the ground anchor, the flushing operation of the casing pipe is enabled when drilling the ground, and the drilling operation is performed when the casing pipe is pulled out. Since the hole bit and the drive shoe can be easily separated from each other, the workability of the ground anchor is dramatically improved compared to the conventional one.

[Brief description of drawings]

FIG. 1 is a cross-sectional view at the time of ground drilling by a drilling device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the hole drilling device showing a state after the steel balls have been dropped.

FIG. 3 is a cross-sectional view of the hole drilling device showing a state where the slide tube has moved.

FIG. 4 is a cross-sectional view of the drilling device showing a state where the slide tube has moved and the connection between the drive shoe and the drilling device has been released.

FIG. 5 is a cross-sectional view of the drilling device showing a detached state of the drive shoe and the drilling bit when the casing pipe is pulled out.

FIG. 6 is a perspective view of a conventional Kronen bit, a drive shoe, and a casing tube.

[Explanation of symbols]

 13 Drive Shoe 15 Engagement Groove 17 Drill Bit 17a Head 17b Cylindrical Part 19 Jet Hole 21 Check Valve 23,43 Valve Seat 27,33 Spring 29 Ball Valve 35 Slide Pipe 45 Ground 47 Anchor Hole 49 Steel Ball 51 Ball key mounting hole 53 Ball key 59 Drilling device

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Akira Higuchi 2-35 Shinozaki-cho, Edogawa-ku, Tokyo Higuchi Engineering Co., Ltd.

Claims (1)

[Claims] 1. A drive shoe, which is screwed to the tip of a casing pipe connected to a hole drilling machine and has an engagement groove formed in the inner periphery thereof, and which is axially meshed with the drive shoe and connected to the tip thereof, It consists of a drill bit that is separated from the drive shoe and remains in the anchor hole when the casing pipe is pulled out, and a steel ball that is dropped from the ground into the casing pipe before pouring the grout material into the casing pipe. The bit has a drilling water ejection hole formed in its head, and is urged toward the rear end side of the tubular part by a check valve and a spring inside the tubular part that is inserted into the drive shoe. A slide tube having a valve seat for holding the steel ball is installed, and the plurality of ball key mounting holes provided in the peripheral wall of the tubular portion are pushed outward from the peripheral wall of the tubular portion by the slide tube. Been Engage with the engagement groove of the drive shoe,
A boring device equipped with a ball key which is disengaged from an engaging groove by movement of a slide tube against a spring force of a spring and drops from a rear end of the slide tube into the slide tube.