JP2954565B1 - Pilot hole drilling rig - Google Patents

Abstract

An object of the present invention is to improve the amount of sunshine and reduce chip wear when drilling a pilot hole for a propulsion hole in a hard rock formation or a hard rock formation. SOLUTION: As a pilot hole excavating device, a hammer bit 5 projecting forward from the roller bit 2 is provided in a turning type pipe cutting machine 3 supporting the roller bit 2.
And a hit-type down-the-hole drill 6 having First, the pipe core is crushed with a hammer bit 5 to form an advanced hole H1.
Is excavated to form a pilot hole H2. By eccentricizing the hammer bit 5 from the pipe core O1, a large advanced hole H1 can be formed by the hammer bit 5 having a small diameter, and the excavation efficiency is further improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pilot hole excavator used for excavating a pilot hole as a pre-process for excavating a tunnel (main propulsion hole) by a propulsion method. The present invention relates to a pilot hole drilling apparatus suitable for propelling and excavating a hard rock stratum or a cemented rock stratum with a small-diameter propulsion that cannot be entered by humans.

[0002]

2. Description of the Related Art 60 tunnels such as a sewer pipe laying tunnel are used.
Even when excavating a small-diameter tunnel of about 0 mmφ to 800 mmφ by the propulsion method, when excavating a layer with a high compressive strength such as a hard rock layer or a cemented rock layer, protection of the bit of the shield device or excavation efficiency In consideration of the above, first, the pilot hole is excavated and cored, and then the propulsion hole is excavated.

[0003] As a drilling device for drilling a pilot hole, a down-the-hole drill having a hammer bit,
There is a swiveling pipe propelling machine or an auger excavator using a casing tube.

[0004]

The compressive strength is 2,000 kg
For hard rock formations or super-hard rock formations of f / cm ^{2 to} 4000 kgf / cm ² class, impact-type down-the-hole drills are considered to be suitable because of their high crushing power, but horizontal propulsion accuracy over long distances And it is difficult to drill a large pilot hole in a beautiful way. In other words, even if the diameter of the hammer bit of the down-the-hole drill is slightly increased, the air hammer mechanism must be enlarged and strengthened to obtain the necessary impact force. Must be enlarged, making construction on a road with a large traffic volume or a narrow road difficult, and the cost is greatly increased. In addition, it leads to an increase in noise.

On the other hand, when a pilot hole is formed by excavating a hard rock formation or a super hard rock formation only with a turning type pipe cutting machine equipped with a roller bit, the tip of the bit is severely worn and the excavation is difficult. Efficiency is poor, and it is not possible to secure a satisfactory amount of progress.

[0006]

According to a first aspect of the present invention, there is provided a pilot hole excavating apparatus according to the first aspect of the present invention, comprising: a pipe drilling machine having a pair of roller bits supported on a head end of a casing pipe; A hitting down-the-hole drill having a hammer bit located closer to the tube core than the roller bit is provided. The pair of roller bits are provided with a large number of chips on the surface of a conical base material portion and have a tube core. The hammer bit is rotatably supported at a symmetric position with respect to the center, and the hammer bit is eccentric from the casing pipe core within a range in which the outer peripheral end of the hammer bit does not deviate from the pipe core, and projects forward from the roller bit, so that the hammer bit The excavation range by the bit and the excavation range by the roller bit overlap in the pipe diameter direction. Fixed an arcuate face plate perpendicular to Utotomoni tube core, it is characterized in that the discharge window is formed on said surface plate.

[0007]

[0008]

[0009]

[0010]

[0011]

FIG. 1 shows an excavation operation state of a pilot hole excavator according to the present invention. The pilot hole excavator includes a pair of roller bits 2 at the tip of a casing pipe (steel pipe) 1 which can be extended. And a down-the-hole drill 6 having a hammer bit 5 protruding forward from the roller bit 2. The down-the-hole drill 6 includes a plurality of stays 8 extending radially. And is fixed in the earliest casing tube 1.

The diameter D1 of the casing tube 1 is equal to the main propulsion hole H0.
Is used. For example, when the diameter of the main propulsion hole H0 is 600 mmφ, the diameter D1 = 35.
The one with 0 mmφ is used. The casing pipe 1 is successively added to the rear side as it is excavated, and the casing pipe 1 at the rear end is held in a horizontal posture by a chuck 11 of a propulsion device 10 installed at the bottom of a shaft 13.

The propulsion unit 10 includes a pair of left and right guide rails 1.
2 and a propulsion device main body 17 supported on the guide rails 15 so as to be movable in the front-rear direction. The propulsion device main body 17 has an inner peripheral surface of a large-diameter hole 19 as shown in FIG. In addition, the rotating ring 20 is supported so as to be freely rotatable and immovable in the front-back direction. The rotary ring 20 is provided with a plurality of chucks 11 of a hydraulic cylinder (or pneumatic cylinder) type at equal intervals in the circumferential direction. A pair of hydraulic cylinders 21 for propulsion are provided at left and right ends of the propulsion unit main body 17, and a pair of left and right drive motors 22 for rotating the rotating ring 20 are provided.

The propulsion hydraulic cylinder 21 has a rod 21a pivotally connected to a front bracket 24 as shown in FIG. 1, so that the propulsion unit main body 17 moves in the horizontal front-rear direction by the expansion and contraction of the hydraulic cylinder 21. It has become. On the ground, a generator 25, an air compressor 26, a hydraulic unit 27 and the like are arranged.
The air hose 28 is connected to the down-the-hole drill 6 through a pipe arranged in the casing pipe 1, and the generator 25 and the hydraulic unit 27 are connected to the propulsion unit main body 17.

FIG. 3 is an enlarged front view of the casing tube 1. The pair of roller bits 2 have their apexes at the tube core O1.
The hammer bit 5 is formed in a conical shape toward the side and is arranged at a symmetrical position about the tube core O1, while the hammer bit 5 is arranged at a position where the center O2 is eccentric by a fixed amount E from the tube core O1. Have been. Hammer bit 5 diameter D2
Is about 1/3 of the diameter D1 of the casing tube 1, for example, about 130 mmφ, and the eccentricity E thereof is slightly smaller than 1/2 of the diameter D2 of the hammer bit, and the outer peripheral end of the hammer bit 5 is displaced from the tube core O1. There is no range. Further, the core portion (apex side portion) of the roller bit 2 enters the pipe core O1 side beyond the swiveling revolving range of the hammer bit 5, and the excavation range of the bits 2 and 5 when the casing pipe 1 turns. Overlap in the radial direction.
An arc-shaped face plate 31 having a discharge window 37 is disposed between the two roller bits 2 in the circumferential direction.

FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3, in which the roller bit 2 is disposed through a saddle 30 in a notch 29 formed at the front end of the casing tube 1. Is welded to the inner peripheral surface of the casing tube 1 and the saddle 3
The inner peripheral surface of the front half of 0 is inclined so as to move away from the tube core O1 as it goes forward, and the inner peripheral surface is provided with a support shaft 32 projecting obliquely forward toward the tube core 01. 3
2, the conical roller bit 2 is rotatably supported via a bearing 33. The roller bit 2 has a number of carbide tips 35 embedded in a random arrangement on the surface of a conical base material. The inclination angle θ of the roller axis O3 with respect to a plane M perpendicular to the tube core O1 is determined by the roller bit. The front edge of No. 2 is inclined such that it is parallel to the surface M or slightly recedes toward the tube core O1 as shown in FIG.

The face plate 31 is arranged at a position perpendicular to the tube core O1 at the foremost edge of the casing tube 1, and a partially cylindrical fitting plate 31a extending rearward is integrally formed at an outer peripheral end thereof. The fitting plate 31a is welded to the outer peripheral surface of the casing tube 1.

The positional relationship between the face plate 31, the front edge of the roller bit 2 and the hammer bit 5 in the front-rear direction will be described. The roller bit 2 has a large part of the front edge slightly forward from the face plate 31. The hammer bit 5 is disposed so as to protrude, and the hammer bit 5 is a fixed amount more than the front edge of the roller bit 2.
For example, they are arranged so as to protrude forward by about 15 cm to 30 cm.

The hammer bit 5 integrally has a spline shaft 40 extending rearward, and the spline shaft 40 is spline-fitted to the inner peripheral spline surface of the spline boss 43 of the down-the-hole drill 6 so as to be axially movable. Yes,
The rear end head 40a of the spline shaft 40 is attached to the air hammer 44.
By hitting the hammer bit 5 continuously, an impact in the axial direction is given to the hammer bit 5. Spline shaft 4
The stroke amount S of 0 is set to about 15 to 20 cm.

Excavation work and operation will be described. In FIG. 1, first, a first (front end) casing pipe 1 provided with two bits 2 and 5 is gripped by a chuck 11 of a propulsion device 10, and is propelled forward while turning around a pipe core O1, and at the same time, down the hole. The compressed air is supplied to the drill 6 to operate the hammer bit 5.

The core of the rock surface is first crushed by the hammer bit 5, but the hammer bit 5 is constantly pressed against the front rock surface, and the hammer is hit in the pressed state and the casing tube 1 is turned. With the tube core O1
Revolves around. Therefore, a small diameter hammer bit 5
However, the advanced hole H1 having the diameter over the revolution range is excavated.

In the case where the hammer bit 5 shown in FIG. 4 suddenly enters the soft layer from the hard rock layer during the hitting operation, the hammer bit 5 shown in FIG. be able to.

[0023] Following the advanced hole H1 as shown in FIG. 4 is formed by turning the Kanshin O1 around (orbiting) to Rutotomoni capable of rotating rollers bit 2, the rock face around the leading hole H1 is drilled Is done. In this excavation work, since a rock surface which is easily broken by excavating the nucleus by the advanced hole H1 is excavated, excavation efficiency is good even with a large diameter such as 350 mmφ.
Further, since the face plate 31 is pressed against a rock surface or soil or crushed stone immediately after excavation, the hammer bit 5
Even if a large lump of stone is separated from the stratum during the excavation process by the
Can be crushed finely.

The crushed stone or soil crushed by the roller bit 2 is removed from the space inside the face plate 31 by the casing pipe 1.
Inside, the large crushed stone is further broken by the tip 35 of the roller core 2 on the tube core side, and is discharged backward in the casing tube 1. The air is also discharged from the discharge window 37 of the face plate 31 into the casing tube 1.

When the pilot hole H2 formed by the roller bit 2 is excavated to a predetermined distance and penetrated to the next pit, the casing tube 1 is pulled out and returned to the ground. Then, although not shown, a shield for main propulsion is installed in the pit. And the propulsion hole is excavated based on the pilot hole H2.

[0026]

[Other Embodiments] (1) FIG.
3 is arranged coaxially with the casing tube 1 (O1 = O2). The distal end of the casing tube 1 has a double tube structure having an inner tube 52, and two roller bits 54, two on the inner periphery of the casing tube 1 and the outer periphery of the inner tube 52, respectively.
55 are provided. Both roller bits 54 and 55 have a truncated conical shape. The outer roller bit 54 has a small diameter portion directed toward the tube core, and the inner roller bit 55 has a large diameter portion directed toward the tube core. A face plate 56 is provided so as to cover between the roller bits.

(2) The number of roller bits can be three or five or more.

[0028]

(1) A structure in which an impact type down-the-hole drill 6 is provided in a revolving-type pipe cutting machine 3, and the hammer bit 5 of the down-the-hole drill 6 precedes the roller bit 2 of the pipe cutting machine 3. Therefore, in one excavation work, first, the pipe core portion is crushed by the hammer bit 5 to form the advanced hole H1, and then the original pilot hole H2 is excavated around the advanced hole H1 by the roller bit 2. Therefore, the pipe core and its surroundings can be excavated by the hammer bit 5 and the roller bit 2 even when excavating a hard rock formation or a super hard rock formation. Can be suppressed and breakage can be prevented.

[0029]
1 (2) A hammer bit 5 of a down-the-hole drill 6 for crushing a pipe core portion is preceded, and subsequently, a pilot hole H2 is formed by drilling around an advanced hole H1 by a roller bit 2 of a pipe cutting machine 3. Therefore, compared to drilling a pilot hole with the same diameter using only a pipe cutter, drilling can be performed quickly with a small propulsion force even in hard rock formations or cemented rock formations. The wear rate can be reduced, the excavation efficiency can be improved, and the amount of sunshine can be improved. Also, the number of bit exchanges is reduced, and the cost can be saved.

(3) Since the hammer bit 5 can be moved ahead and the surrounding area of the advanced hole H1 can be excavated by the roller bit 2, the pilot hole having a long span can be formed while improving the excavation efficiency as described above. Even when excavating, sufficient horizontal accuracy can be maintained.

(4) Connect the hammer bit 5 to the casing tube 1
When the structure is decentered from the pipe core O1, the large advanced hole H1 can be efficiently formed with the hammer bit 5 having a small diameter. Further, since the increase in the diameter of the hammer bit 5 can be prevented, the size and strength of the air hammer mechanism of the down-the-hole drill 6 associated with the hammer bit 5 need not be increased, and the ground equipment such as an air compressor can be downsized. In particular, it is convenient for work on a road with a large traffic volume.

(5) If the amount of eccentricity E of the hammer bit 5 from the tube core O1 is made smaller than the radius of the hammer bit 5 so that the hammer bit 5 overlaps the tube core O1, the portion of the rock surface corresponding to the tube core is always placed. Hit with a hammer bit 5,
Excavation ability is further improved.

(6) If a face plate 31 that covers the circumferential direction of the roller bit 2 and is orthogonal to the tube core O1 is fixed to the tip of the casing tube 1, the surface to be excavated by the roller bit 2 during the excavation work. Since it is always held down by the face plate 31, even if there is a large lump of stone separated from the stratum by the operation of the hammer bit 5, it is crushed by the roller bit 2 while being held by the face plate 31 and discharged into the casing pipe 1. Crushing work is improved. In addition, it is possible to prevent the components inside the casing tube 1 such as the saddle 30 and the down-the-hole drill body from being damaged.

(7) When the digging range by the hammer bit 5 and the digging range by the roller bit 2 are overlapped in the pipe diameter direction, the bits 2 and 5 are all over the entire cross section of the casing pipe 1. The abutment and excavation can be performed, and the wear of the tips 35 and 36 of the bits 2 and 5 can be further reduced.

[Brief description of the drawings]

FIG. 1 is an overall side view showing a working state of a pilot hole excavator to which the present invention is applied.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged front view of a front end of the excavator of FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a front view of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing pipe 2 Roller bit 3 Pipe cutting machine 5 Hammer bit 6 Down the hole drill 10 Propulsion machine 31 Face plate 37 Discharge window

Continuation of the front page (56) References JP-A-63-32092 (JP, A) JP-A-8-199982 (JP, A) JP-B-59-40996 (JP, B2) (58) Fields investigated (Int) .Cl. ⁶ , DB name) E21D 9/08 E21D 9/06 311

Claims (1)

(57) [Claims] 1. A striking down-the-hole drill having a hammer bit located closer to a pipe core than said roller bit is provided in a pipe cutting machine having a pair of roller bits supported on a head end of a casing pipe, The pair of roller bits are provided with a large number of chips on the surface of a conical base material portion, and are rotatably supported at symmetric positions about the tube core. While eccentric from the casing core within the range where the end does not come off from the core, it protrudes forward from the roller bit,
The digging range by the hammer bit and the digging range by the roller bit overlap in the pipe diameter direction, and an arc-shaped face plate that covers the circumferential direction of the roller bit and is orthogonal to the pipe core is fixed to the tip head of the casing pipe 1, A pilot hole excavator, wherein a discharge window is formed in the face plate.