JPS631437B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drilling method used for drilling large diameter holes in rock.

Pole-erecting trucks equipped with an auger-type drilling device are widely used to erect utility poles, but with the auger-type drilling device, it is extremely difficult to drill large-diameter holes in hard rock. It was hot.

The present invention provides a drilling method that can successfully drill pillar holes even in hard rock, and this will be explained below.

The drilling method according to the present invention forms a ring-shaped row of small holes by continuously drilling a plurality of small holes adjacent to each other along the circumference of a desired large-diameter hole, and overlaps the row of small holes. The method is characterized in that the barrier portion remaining between adjacent small holes in the row of small holes is cut out using a cylindrical bit having an annular cutting edge portion of the same diameter, and then the core remaining in the core portion is removed. That is, in the present invention, first, a plurality of small holes are circularly bored in a rock, and a drilling device such as that illustrated in FIGS. 1 and 2 is used for this purpose. The illustrated drilling device includes a column 10, a guide cell 11, a rock drill 12, and a pneumatic cylinder 13 which is a feed device for the rock drill. The pillar 10 is
It is formed as a square bar with chamfered ridges, and a square tubular fixture 15 with a pointed pin 14 is fitted to the lower end. The upper end of the column 10 is fitted into a chuck 19 of a column rotating device 18 consisting of a hydraulic motor 16 and a speed reducer 17, and is fixed by a pin 20. The upper end of the pole rotating device 18 is connected to a boom 21 of a digging pole erecting vehicle that rotates up and down by a hydraulic cylinder (not shown), and is pressed downward by the boom 21. Thereby, the pillar 10 is supported while standing on the bedrock 22. The boom 21 serves as a support device for the support column 10. The column 10 may be supported in other ways, or the column may be rotated manually.

The guide cell 11 is attached to the support column 10 via a cell attachment tool 23 and a cell attachment bracket 24. The guide groove 11c formed in the center of the guide cell 11 has a guide groove 11c formed in the center of the guide cell 11.
5 is slidably attached. An ear-shaped mounting piece 35a is provided on the surface of the carriage 35,
A rock drill 12 is attached to this. Further, a connector 36 is provided on the back side of the carriage 35, and a pneumatic cylinder (rodless cylinder) 13 is attached to this connector.

When using this drilling device, the tip of the thrust rod 14 provided at the lower end of the column 10 is brought into contact with the rock, and the column is supported by the column support device in an erected state. In this case, it is preferable to provide a counterbore in advance in the portion that the thrust rod 14 comes into contact with.
In this state, the drilling rod 34 with the lock bit 41 attached to its tip is fitted onto the rock drill 12, and drilling work is carried out while supplying compressed air to the rock drill 12 and the pneumatic cylinder 13. Of the air hoses shown, 42 are for operating the rock drill, 4
3 is an air hose for blowing, 44 is an air hose for advancing the rock drill, and 45 is an air hose for retracting the rock drill.

Figure 3 shows the method for forming small hole rows.
As shown in this figure, a large number of small holes 3 are continuously drilled adjacent to each other along the circumference 2 of a desired large diameter hole 1, thereby forming an annular small hole row 4.
These small holes 3 are drilled by the rock drill of the drilling device, but when drilling a plurality of holes adjacent to each other like this, the rock drill is drilled first during the work. Escape to the hole next to it,
There is a risk that normal pores will not be formed.
It is preferable to perform the perforation according to the following procedure.
In other words, in Fig. 3, first small holes a and b are provided with an interval of one small hole, and then both of the above-mentioned small holes are provided with an outer diameter close to the inner diameter of the small hole. With the metal rod 5 such as a mild steel rod inserted, a small hole c is bored in the portion sandwiched between the two small holes. In this way, the lock bit moves forward along both metal rods 5 while contacting the metal rods 5 inserted into both small holes, so that straight small holes are formed. small hole c
When the metal rod 5 is drilled, remove the metal rod 5 and follow the steps below.
You can drill holes by repeating the same operations as defghi... The length of the metal rod 5 should be such that it protrudes about 10 to 20 cm above the ground when inserted into the small hole, and a hook is attached to the head of the metal rod so that a wire rope or the like can be hung on it when it is removed. It is preferable to provide

Large-diameter holes with an inner diameter of about 250 to 500 mm are often used as holes for building pillars, but if the inner diameter of large-diameter hole 1 is 450 mm, the diameter of the lock bit for drilling small holes should be reduced. It depends on the performance of the rock machine, but
Approximately 36 to 40 mm is appropriate. The diameter of the guide metal rod 5 is preferably 4 to 5 mm smaller than the diameter of the lock bit. For example, if the diameter of the lock bit is 36 mm, it is preferable to use a rod with an outer diameter of about 32 mm. In addition, when drilling a small hole using the above-mentioned drilling device, once one small hole has been protruded, the support rotating device 18 is operated to rotate the support 10 by a predetermined amount, and the next small hole is drilled. All you have to do is By rotating the support 10, the axis of the drilling rod 34 moves on the same circumference around the support, so a plurality of small holes are successively formed on the same circumference with radius R around the support 10. It is possible to drill holes.

In this way, an annular row of small holes 4 is formed, but in this row of small holes, all adjacent small holes 3 do not always communicate with each other, and depending on the drilling conditions, as shown in FIG. Rocks often remain between the small holes 3 as barrier portions 3a. For this reason, the rock pillar (core) 6 inside the small hole row 4
There is a tendency that the core is not completely erected, making subsequent core removal work difficult. In order to prevent this, after forming the small hole rows, the core 6 is arched (edged) using a cylindrical bit 50 as illustrated in FIGS. 5a and 5b.

The cylindrical bit 50 includes a cutting ring 53 having an annular cutting edge 52 at its tip formed by implanting a plurality of carbide tips 51, and a bit body 54 to which the cutting ring 53 is screwed (S). Additionally, a mounting shaft 55 is integrally provided at the rear end of the bit body 54. The cylindrical bit 50 is attached to the mounting shaft 55.
is attached to the output shaft 58 of the rotating device by fitting into a cylindrical joint 56 attached to the output shaft 58 of the rotating device and fixing with a bolt 7. The pillar 10 of the drilling device and the output shaft 58 include:
It is convenient to use the auger shaft of the commonly used hole-drilling pole-erecting vehicle. In this case, the output shaft 5
8 is rotated by an auger rotation motor (hydraulic motor 16 in the illustrated example). Cylindrical bit 50
If the outer diameter D ₁ of is 460 mm and the inner diameter D ₂ is 430 mm, then
The carbide tip 51 of the cutting edge portion 52 is, for example, 8
It is preferable to implant about 24 square chips of ×10 × 12 (mm) at equal intervals by soldering. At this time,
The carbide chip 51 is tilted and soldered so that one ridge line protrudes by about 2 mm.

FIGS. 6a and 6b show the state in which the cylindrical bit 50 is used, in which rotation and thrust are applied to the cylindrical bit 50 pressed onto the row of small holes 4 in an overlapping manner via the output shaft 58. The barrier portion 3a remaining between the small holes is cut and removed. During this operation, the air tube 59 is inserted into the small hole 3 to discharge compressed air into the small hole row. The cylindrical bit 50 is
It is important to keep the small hole 3 parallel to the drilling direction. Note that the cylindrical bit may be of any shape as long as it can successfully cut the rock between the small holes.

The core 6 thus isolated is crushed and removed by an appropriate method. As a method for crushing the core, for example, one or more pilot holes 7 are bored in the center of the core 6, and slow crushing is performed in which the pilot hole 7 is mainly composed of an inorganic compound mainly composed of silicate. A method can be adopted in which the core is filled with an agent (for example, commercial blister) and the core is crushed by the expansion pressure. In addition, one of the hydraulic stone breakers is installed in the pilot hole 7 above.
After inserting the pair of pressing pieces, by press-fitting a wedge rod into the space between the pressing pieces and pushing the pressing pieces apart,
Core crushing may also be performed. In some cases,
It is also possible to crush the core with a breaker such as a hydraulic breaker that is normally used for crushing rocks without drilling the pilot hole 7. Even in this case, it is more effective to provide the prepared hole 7 in a protruding manner in advance.

In this way, the desired large diameter hole can be obtained. The drilling method according to the present invention forms a row of small holes in a rock, then removes the rock barrier portion remaining in the row of small holes and removes the isolated core to form a desired large-diameter hole. As a result, it has become possible to efficiently drill large-diameter holes for pillar erection even in hard rock.

[Brief explanation of the drawing]

Figures 1 and 2 are front and side views of the drilling device, Figures 3 and 4 are plan views of the row of small holes,
FIGS. 5a and 5b are a side view and a front view of the cylindrical bit, and FIGS. 6a and 6b are a side sectional view and a plan view showing the usage state of the cylindrical bit. 1...Large diameter hole, 3...Small hole, 4...Small hole row,
5... Metal rod, 6... Core, 10... Support column, 12
...Rock drilling machine, 34...Drilling rod, 50...
Cylindrical bit, 51... Carbide tip.

Claims (1)

[Claims] 1. A drilling method for drilling large-diameter holes in rock, in which a ring-shaped row of small holes is formed by continuously drilling a plurality of adjacent small holes along the circumference of a desired large-diameter hole. After cutting off the barrier portion remaining between the adjacent small holes in the small hole row using a cylindrical bit having an annular cutting edge with a diameter that overlaps with the small hole row, the core remaining in the core is removed. A drilling method characterized by removal.