JP3649944B2 - Large-diameter drilling method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a large-diameter drilling method, and particularly to a technique for discharging excavation slime when excavating a large-diameter drilling hole.
[0002]
[Prior art]
For tunnel excavation work in natural grounds with many cracks and slip surfaces, earth and sand grounds, low-strength soft rocks, and expansive grounds, it is necessary to stabilize the natural ground prior to excavation. A long steel pipe tip receiving method is known as a kind of method for improving the stability of a natural ground having such properties.
[0003]
FIG. 3 shows a typical construction state of the ground drilling method in the long steel pipe tip receiving method. In the drilling method shown in the figure, an inner tube rod 2 with a drill bit 1 attached to the tip, an outer tube 3 that houses the inner tube rod 2 inside, and a thrust and rotation on the drill bit 1. And a drifter 4 for applying striking.
[0004]
The inner tube rod 2 is a rod body with screws engraved at both ends, and is sequentially added and coupled through a coupling as the excavation progresses. A medium supply passage 5 for supplying the medium is formed through.
[0005]
The outer pipe 3 is a hollow cylindrical steel pipe with screws engraved at both ends. Like the inner pipe rod 2, the outer pipe 3 is joined and connected by screwing the ends together as the excavation progresses. The space between the inner tube rod 2 and the outer circumferential surface of the inner pipe rod 2 is a discharge passage 6 for the excavation slime b generated during excavation.
[0006]
A swivel 7 is mounted on the rear end side of the outer tube 3, and the swivel 7 has a supply port 8 for the cooling medium a communicating with the medium supply passage 5 of the inner tube rod 2 and excavation communicating with the discharge passage 6. An outlet 9 for slime b is provided.
[0007]
The drifter 4 is connected to the inner tube rod 2 via the shank rod 10. The drifter 4 is supported by the guide cell 12 so as to be movable back and forth via a guide shoe 11 provided at the lower end.
[0008]
A center riser 13 for positioning and supporting the outer tube 3 is provided on the distal end side of the guide cell 12. When the steel pipe is embedded and the natural ground c is reinforced, by driving the drifter 4, thrust, rotation and impact are transmitted to the inner pipe rod 2 and the drill bit 1 through the sunk rod 10. As a result, the natural ground c is excavated to form the hole d.
[0009]
At this time, a cooling medium a selected from drilling water or air is supplied to the medium supply passage 5 through the supply port 8, and this cooling medium a is jetted from the drilling bit 1 toward the natural mountain c. Is done.
[0010]
The cutting powder drilled by the drill bit 1 is mixed with the cooling medium a to form a drilling slime b, and the drilling slime b is discharged to the outside through the discharge port 9 through the discharge passage 6.
[0011]
In the drilling hole d excavated by the drilling bit 1, the thrust and blow of the drifter 4 are applied to the outer pipe 3 from the rear end side, so that the outer pipe 3 is put in the drilling hole d by the boosting method. Inserted.
[0012]
However, such a conventional drilling method has a technical problem which will be described below, particularly when a large-diameter drilling hole having a diameter of 65 mm or more is formed, for example, when the diameter becomes large.
[0013]
[Problems to be solved by the invention]
That is, when a large-diameter drilling hole having a diameter of 65 mm or more is formed, the amount of chipping drilled by the drilling bit 1 is very large, and therefore the amount of drilling slime b to be discharged is naturally large. Become.
[0014]
However, if a large amount of drilling slime b is to be discharged by drilling water or air, a large amount of drilling water or air is required. If a large amount of drilling water is used, the working environment deteriorates due to the generated muddy water. If a large amount of air is used, a large amount of dust is generated, and the working environment is similarly deteriorated.
[0015]
The point of exclusion of the drilling slime b is to secure a flow velocity in the discharge passage 6, and when the hole diameter increases, the amount of the removal medium (hole water or air) increases in proportion to the square of the diameter. Will increase, leading to deterioration of the working environment.
On the other hand, the double-pipe drilling method using the inner tube rod 2 and the outer tube 3 as shown in FIG. 3 is a method adopted when the excavation target ground c is relatively soft. In a simple drilling method, when the outer tube 3 is embedded in the ground c for a predetermined length, the inner tube rod 2 is pulled out, but at this time, it is contained in the excavation slime b in the discharge passage 6. If the powder remains, it is very difficult to pull out the inner tube rod 2.
[0016]
Such problems associated with residual residue can be avoided, for example, by increasing the supply pressure of drilling water or air, but if the supply pressure is increased, cracks in the ground c Another problem arises that loosening occurs and damages natural ground c.
[0017]
The present invention has been made in view of such conventional problems. The object of the present invention is to smoothly discharge excavation slime without damaging the ground and to deteriorate the working environment. It is an object to provide a large-diameter drilling method that does not lead to inconvenience.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, the present invention uses an inner tube rod equipped with a drill bit for drilling a large-diameter drill hole, and an outer tube that accommodates the inner tube rod, and uses the drill bit. Drilling a hole while applying thrust, rotation and blow to the hole, and when drilling the hole, a cooling medium is supplied to the hole bit from a medium supply passage provided inside the inner tube rod, In the drilling method of discharging the drilling slime accompanying excavation to the outside through the slime discharge passage provided between the inner tube rod and the outer tube, and inserting the outer tube into the drilled hole, A bubble associated with compressed air is used as the cooling medium, and the bubble is generated by mixing a foaming agent mixed solution and compressed air. The swivel is provided immediately before the medium supply passage. And the cooling medium is And from the tip of the hole bits to be sprayed toward the natural ground.
According to the large-diameter drilling method configured in this way, the bubbles used for the cooling medium are more viscous than liquids such as drilling water, and the gaps between the soil particles forming the ground, cracks, and slip surfaces The permeability to is small.
Therefore, there is no problem of damaging the so-called natural ground, such as geology that decreases in strength, cracks, and looseness on the sliding surface due to contact with water.
In addition, the drilling slime mixed with bubbles and dust is in a state where the drilled soil particles (chip powder) are attached to the surface of the bubbles, so the soil particles in the drilling slime become clay and enter the discharge passage. It will not stick or the particles will settle down and hinder the discharge.
In addition, the drilling slime mixed with bubbles and drill powder is in a state where the drilled soil particles (chip powder) are attached to the surface of the bubbles, so dust does not occur like air drilling holes, In addition, a large amount of turbid water is not generated like drilling water.
In addition, it is possible to supply bubbles having a high viscosity and a relatively large loss due to pumping in the pipeline in a state where the pumping loss is relatively small.
An antifoaming agent can be mixed with the drilling slime to defoam the bubbles.
According to this configuration, the drilling slime in which bubbles and chipping powder are mixed decreases the volume with the passage of time, and the volume decreases. Can be defoamed.
A power transmission portion such as the thrust is provided on the distal end side of the outer tube, and the outer tube can be inserted into the drilling hole by a forward pulling method.
According to this configuration, it is not necessary to provide a power transmission portion such as thrust on the rear end side of the outer pipe as in the conventional boosting method, and the rear end side of the outer pipe can be opened, so that a large amount of excavation is possible. A structure suitable for discharging slime can be obtained.
The power transmission portion includes a step portion provided on an inner peripheral surface of a casing shoe that is screwed and connected to a tip of the outer tube, and a convex portion provided on an outer peripheral surface of the drill bit and contacting the step portion. Can be configured.
According to this configuration, the outer tube can be inserted into the drilling hole by a forward drawing method with a simple structure.
In addition, when an outer pipe is inserted by such a forward pulling system, a system using an air blow is provided to eliminate drilling slime, but the speed of the drilling slime jumping out from the end of the outer pipe is very high. The slime scatters in the vicinity of the work area, which significantly deteriorates the environment of the work place, and at the same time hits the splattered drilling slime. Then, such a problem can be solved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. 1 and 2 show an embodiment of a large-diameter drilling method according to the present invention.
[0020]
In the drilling method shown in the figure, an inner tube rod 22 having a drill bit 20 mounted at the tip, an outer tube 24 that houses the inner tube rod 22 inside, and a thrust and rotation on the drill bit 20. And a drifter 26 for applying striking.
[0021]
The inner tube rod 22 is a rod body with screws engraved at both ends, and is sequentially added and coupled through a coupling as the excavation progresses. A medium supply passage 28 for supplying the liquid is formed so as to penetrate therethrough.
[0022]
The outer tube 24 is a hollow cylindrical steel tube with screws engraved at both ends, and, like the inner tube rod 22, the end portions are joined together by screwing the ends together as the excavation progresses. The space between the inner pipe rod 22 inserted inside and the outer peripheral surface of the inner tube rod 22 serves as a discharge passage 30 for the drilling slime B generated during the drilling.
[0023]
A swivel 32 is mounted on the rear end side of the inner tube rod 22 and the outer tube 24. The swivel 32 has a supply port 34 for the cooling medium A communicating with the medium supply passage 28 of the inner tube rod 22, and a discharge passage. 30 and a discharge port 36 of the drilling slime B communicating with 30 is provided.
[0024]
The drifter 26 is connected to the inner tube rod 22 via the shank rod 38. The drifter 26 is supported by the guide cell 42 so as to be movable back and forth through a guide shoe 40 provided at the lower end.
[0025]
A centerer 46 for positioning and supporting the outer tube 24 is provided on the distal end side of the guide cell 42. The basic configuration of such a drilling method is the same as this type of conventional method, but the drilling method of the present embodiment is particularly suitable for drilling large-diameter drills with a diameter of 65 mm or more. The construction method is suitable for the following, and has the following remarkable features.
[0026]
That is, first, in the drilling method of the present embodiment, the bubbles F associated with the compressed air E are used as the cooling medium A. Therefore, a mixer 48 is connected to the supply port 34 of the swivel 32 that communicates with the medium supply passage 28.
[0027]
The mixer 48 is connected to a compressor 50 that supplies the compressed air E and a pump 52 that supplies a mixed solution G containing a foaming agent such as a surfactant. The mixer 48 includes a medium supply passage. Just before 28, the compressed air E and the mixed solution G are supplied.
[0028]
The mixed solution G containing the foaming agent and the compressed air E sent from the pump 52 enters the swivel 32 in a gas-liquid two-phase state. This two-phase flow passes through a complicated passage in the swivel 32 and enters the medium supply passage 28. When the two-phase flow passes through the passage of the swivel 32, the two-phase flow foams and is supplied to the passage 28 as bubbles F. .
[0030]
FIG. 2 is an enlarged view of the vicinity of the drill bit 20 shown in FIG. 1, and the drill bit 20 of this embodiment is composed of a ring lost bit 20a and an inner bit 20b. The inner bit 20b fitted into the ring lost bit 20a is inserted into the casing shoe 54.
[0031]
At the rear end side of the inner bit 20b, the front end side of the inner tube rod 22 is screwed, and on the outer peripheral surface, a groove 20c that is divided along the circumferential direction is provided on the shaft of the inner bit 20b. It is provided along the direction.
[0032]
The casing shoe 54 is a hollow cylindrical body that is open at both ends. The distal end side of the outer tube 24 is fitted and connected to the rear end side, and the rear end outer peripheral portion of the ring lost bit 20a is connected to the distal end side. It is mated.
[0033]
The medium supply passage 28 provided in the inner tube rod 22 extends through the axial direction of the inner bit 20b and opens at the tip of the inner bit 20b.
[0034]
The front end side of the recessed groove 20c provided on the outer periphery of the inner bit 20b opens to the outer peripheral edge of the front end of the inner bit 20b, and the rear end side of the recessed groove 20c is the outer peripheral surface of the inner tube rod 22 and the outer tube 24. It communicates with the discharge passage 30 of the drilling slime B provided between the inner peripheral surface.
[0035]
Between the inner bit 20b and the casing shoe 54, a power transmission portion 56 for thrust and striking force applied from the drifter 26 is provided. The power transmission portion 56 of the present embodiment includes a step portion 58 provided on the casing shoe 54 and a convex portion 60 provided on the inner bit 20b.
[0036]
The stepped portion 58 is located substantially at the center in the axial direction of the casing shoe 54 and is provided on the inner peripheral surface thereof. The convex portion 60 is formed so as to protrude from the outer periphery of the rear end side of the inner bit 20b, and is divided by the concave groove 20c, so that the step portion 58 and the convex portion 60 come into contact with each other.
[0037]
When thrust and striking force are applied to the inner tube rod 22 from the drifter 26 in a state where the stepped portion 58 and the convex portion 60 are in contact with each other, the thrust and striking force are applied to the casing via these abutting portions. It is also transmitted to the outer tube 24 via the shoe 54, so that the outer tube 24 can be inserted into the drilling hole D by the forward drawing method.
[0038]
When the outer pipe 24 made of steel pipe is embedded to reinforce the natural ground C, by driving the drifter 26, thrust, rotation, and blow are caused by the inner rod 22 and the drill bit 20 via the shank rod 38. As a result, the natural ground C is excavated and the drilling hole D is formed.
[0039]
At this time, the cooling medium A composed of the bubbles F associated with the compressed air E is supplied to the medium supply passage 28 through the supply port 34, and the cooling medium A is directed from the drilling bit 20 toward the natural ground C. Is injected.
[0040]
The drilled powder drilled by the drill bit 20 is mixed with the cooling medium A to form drilling slime B, and the drilling slime B is discharged to the outside through the discharge port 36 through the discharge passage 30.
[0041]
The drilling slime B discharged to the outside contains bubbles F, and the bubbles F obtained by foaming a surfactant or the like will be defoamed over time. In that case, the foam F contained in the drilling slime B can be defoamed by jetting and mixing an antifoaming agent.
[0042]
In the drilling hole D excavated by the drilling bit 20, the thrust and impact of the drifter 26 are applied to the outer tube 24 from the front end side. Inserted into.
[0043]
By continuing such an operation, when the outer tube 24 is embedded in the natural ground C for a predetermined length, the operation is stopped, the inner tube rod 22 is recovered together with the inner bit 20b, and the drilling step is completed. To do.
[0044]
Now, according to the large-diameter drilling method performed as described above, the bubbles F used in the compressed air E are used for the cooling medium A, and the bubbles F used for the cooling medium A are like the drilling water. Compared to other liquids, it has higher viscosity and less permeability to the gaps, cracks, and sliding surfaces of the soil particles forming the ground C.
[0045]
Therefore, there is no problem of damaging the so-called natural ground C, such as geology in which the strength decreases, cracks, or looseness on the sliding surface when touching water.
[0046]
In addition, the drilled slime B in which the bubble F and the ground powder are mixed is in a state in which the soil particles (chip powder) that have been drilled adhere to the surface of the bubble F. , It does not adhere to the discharge passage 30 or the particles settle, and the discharge is not hindered.
[0047]
In addition, drilling slime B, which is a mixture of bubble F and drill dust, is in a state where the drilled soil particles (chip powder) are attached to the surface of bubble F, so that dust is generated like air drilling holes. In addition, a large amount of turbid water is not generated like drilling water.
[0048]
In the case of the present embodiment, the bubbles F are generated by mixing the foaming agent mixture G and the compressed air E, and the bubbles F are generated immediately before the medium supply passage 28. It is possible to supply the bubbles F having a high viscosity and a large loss due to the pumping in the pipe line with a relatively small pumping loss.
In this case, if the foaming agent mixture G and the compressed air E are fed in a gas-liquid two-phase state to generate bubbles F in the vicinity of the drill bit 20, the loss can be further reduced. Can do.
[0049]
In the case of the present embodiment, a power transmission portion 56 such as thrust is provided on the distal end side of the outer tube 24, and the outer tube 24 is inserted into the drilling hole D by a forward drawing method. Therefore, unlike the conventional boosting method, there is no need to provide a power transmission portion such as thrust on the rear end side of the outer tube 24, and the rear end side of the outer tube 24 can be opened, so that a large amount of drilling slime can be obtained. It is possible to make the structure suitable for discharging.
[0050]
That is, in the embodiment shown in FIG. 1, the excavation slime B discharge port 36 is provided in the swivel 32, but in the present embodiment, this discharge port 36 is not necessarily required, and the outer tube 24 is not provided. It is only necessary to open the rear end and support it coaxially with the inner tube rod 22 by the center riser 46.
[0051]
This can also be considered as follows. That is, in the case of the embodiment shown in FIG. 1, since the bubbles F are adopted as the cooling medium A, even if the discharge port 36 communicating with the discharge passage 30 in a bent state is provided, the viscosity of the bubbles F The drilling slime B can be discharged smoothly.
[0052]
However, when drilling water or air is used as the cooling medium, if such a bent discharge port 36 is provided, the excavation slime B stagnates at the bent portion, thereby hindering discharge.
[0053]
Furthermore, in the case of the present embodiment, the power transmission portion 56 includes a step portion 58 provided on the inner peripheral surface of the casing shoe 54 that is screwed and connected to the tip of the outer tube 24, and the outer peripheral surface of the drill bit 20. The outer tube 24 can be inserted into the drilling hole D by a forward drawing method with a simple structure.
[0054]
【The invention's effect】
As described above in detail in the embodiment, according to the large-diameter drilling method according to the present invention, the excavation slime can be smoothly discharged without damaging the natural ground, and the working environment can be deteriorated. There is no.
[Brief description of the drawings]
FIG. 1 is a cross-sectional explanatory view of a construction state showing an embodiment of a large-diameter drilling method according to the present invention.
FIG. 2 is an enlarged view of a main part of FIG.
FIG. 3 is a cross-sectional explanatory view of a construction state showing an example of a conventional drilling method.
[Explanation of symbols]
20 Drilling bit 22 Inner tube rod 24 Outer tube 26 Drifter 28 Medium supply passage 30 Discharge passage 32 Swivel A Cooling medium B Drilling slime C Ground D D Drilling hole E Compressed air F Bubble

Claims (4)

Using an inner pipe rod equipped with a drill bit for drilling a large-diameter drill hole, and an outer pipe that accommodates the inner pipe rod inside,
A drilling hole is excavated while applying thrust, rotation and blow to the drilling bit, and when drilling the drilling hole, a cooling medium is supplied to the drilling bit from a medium supply passage provided inside the inner tube rod. While supplying
In the drilling method of discharging the drilling slime accompanying excavation to the outside through the slime discharge passage provided between the inner tube rod and the outer tube, and inserting the outer tube into the drilled hole,
Using bubbles associated with compressed air as the cooling medium ,
The bubbles are generated by mixing a foaming agent mixture and compressed air, and the bubbles are generated in a swivel provided immediately before the medium supply passage.
A large-diameter drilling method characterized by injecting the cooling medium from a tip of the drill bit toward a natural ground . 2. The large-diameter drilling method according to claim 1, wherein an antifoaming agent is mixed with the drilling slime to defoam the bubbles. 3. The large-diameter drilling method according to claim 1 or 2, wherein a power transmission portion such as the thrust is provided on a distal end side of the outer tube, and the outer tube is inserted into the drilling hole by a forward pulling method. The power transmission portion includes a step portion provided on an inner peripheral surface of a casing shoe that is screwed and connected to a tip of the outer tube, and a convex portion provided on an outer peripheral surface of the drill bit and contacting the step portion. The large-diameter drilling method according to claim 3, wherein:

Images