JP2756593B2 - Underground drilling rig - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an underground excavator used for a horizontal propulsion method, a circular propulsion method, or the like.

[Conventional technology]

When burying a gas pipe, a water pipe, or the like, there is known a construction method in which a buried pipe or the like is excavated in a horizontal or arc shape by a non-cutting method.

In this method, as the cutting distance becomes longer, an error is more likely to occur in the cutting direction, and therefore, it is necessary to frequently perform hole bending correction during cutting.

Conventionally, as a hole bending correction method, multiple hydraulic jacks are provided between the blade port and the casing to change the direction of the blade port to correct the hole bending. A method to correct the bend with a pilot head incorporating a jack to be moved Insert a dyna drill with a bend at the tip into the inner pipe for drilling, pre-drill from the inner pipe tip, and then follow this drill A method of correcting a hole bending by moving an inner pipe and an outer pipe forward is known.

However, in the above-described method, since the cutting edge which is short in the longitudinal direction is corrected by the hydraulic cylinder, it may be difficult to correct the cutting edge depending on the earth pressure. Further, in the above method, the problem of the above method is solved because of the long pilot head, but since the pilot pipe and the pilot head are connected by a hinge assembly, the hole is bent due to the earth pressure received by the blade. Therefore, it is necessary to frequently perform the hole bending correction, which reduces the drilling efficiency. In addition, this method has a hydraulic cylinder, a bend detector, and a movable part at the tip, and there is a problem that a trouble is likely to occur particularly in long-distance propulsion. Furthermore, since all of the above methods use a hydraulic cylinder or the like, the driving hydraulic hose is also long in the case of long-distance propulsion, and if an accident such as hydraulic leakage occurs, a great deal of recovery is required. It costs money and time.

In the other method, it is necessary to change tools such as dyna drill insertion and removal every time a correction work is performed, and the work is complicated, and the drilling efficiency has to be reduced.

In contrast to the above method, in a double-pipe type excavator consisting of an outer pipe and an inner pipe, the tip of the inner pipe is formed obliquely, and when the direction is corrected, the oblique end is directed in a predetermined direction. The inner pipe is pushed forward and displaced in the correction direction by receiving the reaction force of the earth wall at the slanted tip, and then the outer pipe is advanced along the inner pipe to correct the direction. An apparatus of a system adapted to perform the operation is known. Also, in the single-pipe type excavator, the tip of the cut-off pipe is formed obliquely, and when correcting the direction, the cut-off pipe is pushed in with the beveled end directed in a predetermined direction, so that the excavation from the earth wall is performed. 2. Description of the Related Art There is known an apparatus of a system in which a tip of a cutting tube is displaced in a correction direction by a reaction force.

However, since the former of these devices corrects the direction only by pushing the inner tube in a non-rotating state,
There is a disadvantage that it can only be used for cutting a relatively short distance.In addition, even if the direction is corrected by extruding the inner pipe, if the outer pipe with high rigidity is propelled along the inner pipe,
Due to the rigidity of the outer tube, the soil wall on the tip side of the inner tube collapses, and the inner tube is returned to its original position, and there is a big problem that a sufficient correcting function cannot be performed. In particular, such a problem is remarkable in a collapsible ground such as a stagnant sand layer, and in practice, this method can be applied only to a hard ground having high autonomy.

The latter method is also unsuitable for long-distance cutting because the direction is corrected by simply pushing the cutting tube. In addition, as described above, the direction correction simply pushes the drilling pipe, and in addition, in order to receive the earth pressure at the beveled tip, it is necessary to block the soil in the drilling pipe to some extent, Soil cannot be sufficiently taken in, and therefore, a large pushing amount cannot be secured at the time of correction, so that an efficient bending action cannot be expected.

As described above, a sufficient bending action cannot be obtained with the conventional device, and it can be said that there is almost no device that can efficiently perform bending correction particularly on a pipe having a rigid outer diameter exceeding 250 mm.

The present invention has been made in view of such a conventional problem, and it is possible to appropriately correct the cutting direction regardless of the cutting distance even for a pipe having a relatively large diameter. It is an object of the present invention to provide a device which does not need to change tools, has a simple structure, has few failures, and can efficiently perform excavation itself.

[Means for solving the problem]

For this reason, the apparatus of the present invention comprises an outer pipe and an inner pipe each having a tip bit, and in a double-pipe type excavating apparatus for cutting by the tip bits while rotating the outer pipe and the inner pipe, A part of the outer surface of the outer tube on the distal end side in the circumferential direction is provided with an inclined surface inclined in the outer tube axial direction toward the outer tube distal end.

[Action]

In such an apparatus, the inner pipe and the outer pipe are rotated at the time of normal cutting, and both pipes are cut at the same time by excavating with each tip bit.

Fluid such as water is supplied to the excavation section through an inner pipe or the like, and the earth removed by the excavation is taken in from between the inner pipe and the outer pipe and discharged to the pipe starting side.

When the direction is corrected, the outer pipe is circumferentially adjusted so that the inclined surface of the outer end of the outer tube (the inclined surface formed on a part of the outer surface of the tube in the circumferential direction) faces in the direction opposite to the correction direction. . Then, while rotating the inner tube from this state, the outer tube is not rotated and both tubes are simultaneously propelled. Thereby, the inclined surface of the outer surface of the outer tube receives the reaction force of the earth wall, and the direction of the outer tube is corrected in a direction opposite to the inclined surface forming side.

Such a direction correcting function of the present invention is particularly effective on collapsed ground such as a stagnant sand layer. That is, as in the direction correction in a conventional double-pipe type drilling rig, in a method in which the inner pipe is advanced in the correction direction first, and then the outer pipe is advanced along the inner pipe, the rigidity of the outer pipe causes the outer pipe to advance. Most of the pushing force is received at the tip of the inner pipe that protrudes from the outer pipe, and that force acts on the earth wall, causing the ground to collapse and the inner pipe to return to its original direction (the direction before correction). There is a risk that it will. On the other hand, in the present invention, since the outer tube itself is bent by the inclined surface of the outer tube tip, the pushing force is received by the entire outer tube, and therefore the pushing force is concentrated on the earth wall on the outer tube tip side. And the collapse of the earth wall is prevented. Further, even if the soil wall is disintegrated to some extent due to the first excavation of the inner pipe, the slope of the outer surface of the outer pipe rides on the disintegrated earth and sand, so that a further bending effect can be obtained.

Also, at this time, the outer pipe is not simply pushed into the earth wall, but is pushed into the excavation hole dug by the inner pipe, so that a large pushing amount can be secured.

In the case of the arc propulsion method, the above-described direction correcting function is also used to gradually correct the direction of the pipe in an arc shape.

[Embodiment] FIGS. 1 to 3 show an embodiment of the apparatus of the present invention.

The device of the present invention comprises an outer tube 1 and an inner tube 2, and the outer tube and the inner tube are propelled while being rotated (usually rotated in opposite directions) by a rotation / propulsion device on the starting side.

The outer tube 1 has an inclined surface 3 on a part of the outer surface of the tube on the distal end side (range L in the figure) in the circumferential direction. The inclined surface 3 is inclined in the outer tube axial direction toward the outer tube tip. The angle of the inclined surface 3 with respect to the axis of the outer tube is usually set to about several degrees. Note that the inclined surface 3 does not necessarily need to be planar, and may be configured such that all or part of the longitudinal direction is curved.

Bits 4 are provided at a plurality of locations in the circumferential direction of the outer tube tip.

The inner tube 2 has a bit 5 at the tip end thereof and a retractable retractable bit 6 at a plurality of circumferential positions (three in the present embodiment) of a tip portion to be projected from the outer tube. I have. The retract bit 6 is erected in a direction perpendicular to the axis of the inner tube by the action of a spring (not shown) or the like, and falls down toward the distal end of the inner tube against the action, so that It is designed to be stored in.
By allowing the retract bit to be turned upside down as described above, the inner pipe 2 can be easily extracted from the outer pipe 1 even during excavation. The retract bit 6 has such a length that a drill hole corresponding to the outer diameter of the outer tube can be formed by rotating the inner tube.

Further, a plurality of contact portions 8 to be brought into contact with the inner surface of the outer tube are protruded at a plurality of positions in the outer circumferential direction of the inner tube portion located inside the outer tube. In the device of the present invention, the soil is discharged to the starting side through the gap S between the outer pipe 1 and the inner pipe 2,
The contact portions 8 are provided at intervals in the circumferential direction of the inner tube so as not to close the gap S for discharging the earth.

A fluid jet nozzle 9 is provided at the tip of the inner tube 2,
Fluid such as water supplied through the inner pipe is jetted from the jet nozzle 9 to the excavation part.

An example of a specific structure having the above configuration is as follows.

・ Outer tube outer diameter: 200 ~ 300mm ・ Slope: Tilt: around 7 ° Length: around 500mm ・ Projection length of inner tube from outer tube: around 450mm For the above devices, normal cutting (straight digging) Is performed, both pipes are propelled while rotating the outer pipe 1 and the inner pipe 2. Fluid such as water is supplied to the excavation section through the inner pipe 2, and the discharged slurry is taken in from the gap S between the inner pipe 2 and the outer pipe 1 and discharged to the starting side of the pipe.

The cutting direction is detected by a gyro or the like at an arbitrary stage during excavation, and if an error in the direction exceeds an allowable range, the direction is corrected at that stage.

4 (A) and 4 (B) show a method of correcting the direction. After cutting is stopped in the state shown in FIG. 4 (A), the direction to be corrected by a gyro or the like and the correction amount are detected. Then, the inclined surface 3 of the outer tube 1 is turned in the direction opposite to the azimuth to be corrected in the radial direction of the outer tube. Then, in this state, the inner pipe 2 is rotated, and the outer pipe 1 is set in a non-rotating state, so that the two pipes are simultaneously propelled. By this propulsion, the inclined surface 3 of the outer tube receives the reaction force of the earth wall as shown in FIG. 4 (B), and the direction of the outer tube 1 is corrected together with the inner tube 2 in the direction opposite to the inclined surface 3. .

Such a direction correcting function of the present invention has a remarkable direction correcting action on collapsed ground. According to the experiments performed by the present inventors, the direction was corrected in the collapsed ground by using the outer tube having the outer tube having a size of 285 mm, the angle of the inclined surface 3 being 7 °, and the length thereof being 500 mm. Correction in the direction), it was confirmed that the propulsion distance would rise by 4 cm per 3 m. As described above, the device of the present invention exerts a great effect on the collapsed ground because the direction correction is performed by bending the outer tube itself, so that the pushing force at the time of correction (about 7 ton in the case of the above-described experimental example) is reduced. This is because the pipe is received by the entire pipe, thereby preventing the collapse of the earth wall at the time of pushing. In contrast,
When the inner tube is bent and the outer tube is made to follow it, as in the conventional device having a slope at the tip of the inner tube, almost all of the pushing force at the time of correction is at the tip of the inner tube protruding from the outer tube. Therefore, a large force acts on the soil wall from the inner pipe to cause collapse of the soil wall, and the inner pipe is returned to the original direction (the direction before correction).

The device of the present invention can perform not only the vertical direction correction but also the direction correction in an arbitrary direction by turning the inclined surface 3 to the side opposite to the direction to be corrected by 180 °.

The device of the present invention can be applied not only to the horizontal propulsion method but also to an arc propulsion method for propelling a pipe in an arc shape. The pipe is propelled in an arc by alternately repeating the excavation to correct the direction.

In addition, the apparatus of the present invention uses a method in which the outer pipe itself is a buried pipe, and uses the outer pipe as a pilot pipe, connects a hole-expanding bit to the outer pipe on the cutting-reach side, and embeds the hole-expanding bit in the rear part. The present invention can be applied to any of the construction methods in which the outer tube is drawn toward the starting side while the tube is entrained.

〔The invention's effect〕

According to the present invention described above, the following effects can be obtained.

Correction of the cutting direction can be performed reliably and efficiently, and particularly, a large bending correction effect that cannot be obtained by the conventional device can be obtained in a collapsed ground.

Due to its excellent bending correction function, it is possible to appropriately perform bending correction even for a tube whose outer diameter exceeds 250 mm.

When correcting the direction, the outer pipe is pushed into the pre-drilled hole by the inner pipe instead of simply pushing the pipe into the earth wall,
It can be applied to long-distance cutting without any problems.

Since the removal of the earth is sufficiently taken in during the direction correction cutting, a large pushing amount can be obtained, and also from this aspect, the bending can be efficiently corrected.

There is no need to change tools at the time of direction correction, the structure is simple, the number of failures is small, and normal excavation itself can be efficiently performed.

INDUSTRIAL APPLICABILITY As described above, the present invention can reliably and efficiently correct the direction regardless of the cutting distance, the pipe diameter, and the like, and is an extremely versatile apparatus as an underground excavation apparatus for buried pipes.

[Brief description of the drawings]

1 to 3 show an embodiment of the apparatus of the present invention. FIG. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. FIG. 3 is a sectional view taken along the line III-III in FIG. 1. 4 (A) and 4 (B) are explanatory views showing a case where the direction is corrected by the apparatus of the present invention. In the figure, 1 is an outer tube, 2 is an inner tube, and 3 is an inclined surface.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Koji Ueda Koji Ueda 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. Hiroshi Omori 7-14-5 Chuo, Yamato City, Kanagawa Prefecture

Claims (1)

(57) [Claims] 1. A double-pipe excavator, which comprises an outer pipe and an inner pipe each having a tip bit, and excavates with each of the tip bits while rotating the outer pipe and the inner pipe. In the part of the outer surface of the pipe in the circumferential direction,
An underground excavator having an inclined surface inclined in the axial direction of the outer tube toward the tip of the outer tube.