JP2006265993A - Pipe installation method for stabilizing ground, prelining method for tunnel and excavation device used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe installation method for stabilizing the ground, a prelining method for a tunnel and an excavation device used therefor by which excellent drilling efficiency is obtained as the drilling speed is not reduced even when the drilling depth is increased. <P>SOLUTION: The method is to install a pipe in the ground for stabilization of the ground using the excavation device comprising an outer pipe 1, an inner pipe 2, a down hole hammer 4 mounted on a front end side of the inner pipe 1, and an inner pipe bit 20 being fitted to the front end of the down hole hammer 4 and having a shape to bring a bias force in the drilling direction in the relation with the drilling reaction of the ground when the drilling is conducted only by imparting a striking force by the down hole hammer 4. When drilling a straight hole, the drilling is conducted while imparting a rotational force around the axial center and the striking force by the down hole hammer 4 to the inner pipe bit 20. When correcting a bent hole accompanying the drilling process, the drilling is carried out only by the striking force by the inner pipe bit 20. After the drilling to a target length, the outer pipe 1 is left in the ground so that it may serve as the pipe for stabilization of the ground. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tube installation method for stabilizing ground, a tunnel tip receiving method, and an excavation apparatus used therefor.

  When constructing underground structures, such as tunnels, a pre-construction method that installs or builds a tube above the underground structure is generally used prior to constructing the underground structure in order to stabilize the ground, especially ground. Has been. This tubular body contributes to the stabilization of the ground by itself or by further reinforcing the tubular body as an injection passage for the injection material.

With the recent orientation of large-section tunnels, the need for a pre-receiving method is increasing. There are pipe roof construction methods and fore-piling construction methods that start construction from the wellhead, but there is a problem that construction efficiency is not high because the drilling length is short. In order to install a long tubular body, it is necessary to drill a hole without a hole along the target excavation line. Therefore, the present inventors have been able to reliably correct the bending of the hole during the drilling process, so that it is possible to make a long drilling, the tube installation method for stabilizing the ground, the tunnel tip receiving method and the hole bending An excavator having a correction function has been proposed (see Patent Document 1).
JP 2004-263431 A

However, in the above invention, a top hammer type (rotary percussion type) drilling drive device is mainly used, and a striking force is applied to the proximal end side of the inner pipe, which is transmitted to the inner pipe bit. As the drilling depth becomes deeper, it becomes difficult to transmit the striking force to the bit at the tip, so that the drilling speed is reduced and the drilling efficiency is deteriorated.
Therefore, the main problem of the present invention is that the drilling speed does not slow down even when the drilling depth is deep and the ground stabilization pipe installation method with excellent drilling efficiency, the tunnel tip receiving method, and the excavation used therefor To provide an apparatus.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
According to the first aspect of the present invention, an outer tube, an inner tube, a down-the-hole hammer attached to the tip side of the inner tube, and a tip attached to the tip-end of the down-the-hole hammer, the cutting force is applied only by the down-the-hole hammer. When the hole is drilled, the pipe for stabilizing the ground is formed using an excavator having an inner pipe bit having a shape that generates a force that decenters the drilling direction in relation to the drilling reaction force of the ground. It is a construction method that is installed in the ground, and in the case of straight drilling, drilling is performed while giving the inner pipe bit a rotational force around the axis and a striking force by the down-the-hole hammer. At the time of correction, drilling is performed only with the striking force of the inner pipe bit, and after drilling the above-mentioned drilling hole to a target length, the outer pipe is left in the ground to form a pipe for stabilizing the ground. The ground is characterized by A reduction for tube installation method.

<Invention of Claim 2>
According to a second aspect of the present invention, the inner pipe bit has a tapered shape having a pressure receiving surface inclined with respect to the axial center direction of the inner pipe. is there.

<Invention of Claim 3>
According to a third aspect of the present invention, an outer pipe bit is attached to the tip of the outer pipe, and the outer pipe bit has a taper shape having a pressure receiving surface with substantially the same inclination angle as the inner pipe bit, and By engaging with the inner tube bit, the inner tube bit rotates in the same direction as the inner tube bit rotates. The pipe bit and the outer pipe bit rotate, and the inner pipe bit applies a striking force to perform drilling, and when correcting the bending of the hole due to the drilling, the inner pipe bit performs drilling only with the striking force. Item 2. A tube installation method for stabilizing a ground according to Item 2.

(Effects of the Inventions of Claims 1 to 3)
As the inner pipe bit, when the hole is drilled by applying only the striking force, a shape that generates a force that decenters the hole in a certain direction due to the drilling reaction force of the ground is used. For example, if the inner pipe bit is tapered with a pressure receiving surface inclined with respect to the axial direction of the inner pipe, the bit (and the tip of the tube body) is also tapered by the impact force of the down-the-hole hammer (inclined). Escape in the direction toward the tip of the surface. The present invention actively adopts this principle.
That is, by performing drilling while giving the inner pipe bit a rotational force around the axis and a striking force by the down-the-hole hammer, the relief force is offset by the rotation of the pressure receiving surface (inclined surface). Drilling is guaranteed. On the other hand, by performing drilling only with the striking force of the inner pipe bit, the drilling direction is decentered toward the tip of the pressure-receiving surface with the taper inclined in relation to the drilling reaction force (cutting resistance) of the ground. A force is generated, and it becomes possible to correct the hole bending accompanying the drilling.
In the ground excavation apparatus according to the present invention, since the impact force is given to the inner pipe bit by the down-the-hole hammer attached to the distal end side of the inner pipe, there is little transmission loss of the impact force, and even if the drilling depth becomes deeper There is no risk of slowing down. Therefore, the drilling efficiency is superior to the top hammer method (rotary percussion method) in which the striking force is applied to the proximal end side of the conventional inner pipe.
An outer tube bit is attached to the tip of the outer tube, and the outer tube bit is tapered with a pressure-receiving surface having substantially the same inclination angle as the inner tube bit, and is engaged with the inner tube bit to By adopting a configuration in which the tube bit rotates in the same direction, the drilling efficiency can be further improved.

<Invention of Claim 4>
The invention according to claim 4 includes an outer tube, an inner tube, a down-the-hole hammer attached to the tip side of the inner tube, a tip attached to the tip of the down-the-hole hammer, and a cutting force applied only by the down-the-hole hammer. When a hole is drilled, an excavator equipped with an inner pipe bit having a shape that generates a force that decenters the drilling direction in relation to the drilling reaction force of the ground is used to Prior to excavation, this is a pre-construction method in which a pipe body is built along a tunnel line, and in the case of straight drilling, the inner pipe bit is cut while giving rotational force around the axis and striking force by the down-the-hole hammer. When drilling and correcting the bending due to drilling, drilling is performed only with the striking force of the inner pipe bit, and after drilling the above drill hole to the target length, the outer pipe is left in the ground. Ground Is later subjected method of tunnel, which comprises a tube for stabilization.

<Invention of Claim 5>
The invention according to claim 5 is the tunnel tip receiving method according to claim 4, wherein the inner pipe bit has a tapered shape having a pressure receiving surface inclined with respect to the axial direction of the inner pipe.

<Invention of Claim 6>
According to a sixth aspect of the present invention, an outer tube bit is attached to the tip of the outer tube, and the outer tube bit has a tapered shape having a pressure receiving surface with substantially the same inclination angle as the inner tube bit, and By engaging with the inner tube bit, the inner tube bit rotates in the same direction as the inner tube bit rotates. The pipe bit and the outer pipe bit rotate, and the inner pipe bit applies a striking force to perform drilling, and when correcting the bending of the hole due to the drilling, the inner pipe bit performs drilling only with the striking force. Item 6. The tunnel receiving method according to Item 5.

(Effects of the Inventions of Claims 4 to 6)
The present invention provides significant advantages in a prior construction method in which a tube is built along the tunnel line prior to tunnel excavation above the tunnel cross section. Specifically, from the point of view of drilling accuracy, about 15m, even if the accuracy is neglected to some extent, by selecting a drilling length of 100m or more and construction machine, drilling of 300m or more is possible. In addition, the drilling speed is improved and the drilling efficiency is superior compared to the top hammer method (rotary percussion method) that applies a striking force to the proximal end side of the conventional inner pipe.

<Invention of Claim 7>
The invention according to claim 7 includes an outer tube, an inner tube, a down-the-hole hammer attached to the tip side of the inner tube, and a tip attached to the tip-end of the down-the-hole hammer. An excavator provided with an inner pipe bit having a shape that generates a force that decenters the drilling direction in relation to the drilling reaction force of the ground when the hole is drilled. A structure in which drilling is performed while applying a rotational force around the axis to the tube bit and a striking force by the down-the-hole hammer, and when correcting the bending of the hole due to the drilling, the drilling is performed only by the striking force by the inner tube bit The excavator is characterized by that.

<Invention of Claim 8>
The invention according to claim 8 is the excavator according to claim 7, wherein the inner pipe bit has a tapered shape having a pressure receiving surface inclined with respect to the axial direction of the inner pipe.

<Invention of Claim 9>
According to the ninth aspect of the present invention, an outer tube bit is attached to the tip of the outer tube, and the outer tube bit has a tapered shape having a pressure-receiving surface having substantially the same inclination angle as the inner tube bit, and By engaging with the inner tube bit, the inner tube bit rotates in the same direction as the inner tube bit rotates. The pipe bit and the outer pipe bit rotate, and the inner pipe bit applies a striking force to perform drilling, and when correcting the bending of the hole due to the drilling, the inner pipe bit performs drilling only with the striking force. Item 9. The excavator according to Item 8.

(Effects of inventions of claims 7 to 9)
The excavator of the present invention can be used well for each of the above-described construction methods. Specifically, by selecting and adjusting the rotational force around the axis of the inner pipe bit and the striking force by the down-the-hole hammer, it is possible to switch between the straight-cutting hole and the correction mode of the hole bending. Further, in the ground excavation device according to the present invention, the impact force is given to the inner pipe bit by the down-the-hole hammer attached to the distal end side of the inner pipe, so that the transmission loss of the impact force is small and the drilling depth is deep. There is no risk that the drilling speed will slow down. Therefore, the drilling efficiency is superior to the top hammer method (rotary percussion method) in which the striking force is applied to the proximal end side of the conventional inner pipe.
An outer tube bit is attached to the tip of the outer tube, and the outer tube bit is tapered with a pressure-receiving surface having substantially the same inclination angle as the inner tube bit, and is engaged with the inner tube bit to By adopting a configuration in which the tube bit rotates in the same direction, the drilling efficiency can be further improved.

According to the present invention, even if the drilling depth is increased, the drilling speed is not reduced, and there are advantages such as excellent drilling efficiency.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
(Relationship between the tube used and the rotation drive device)
As shown in FIGS. 1 and 4, the tube used is a double tube made up of an outer tube 1 and an inner tube 2. The outer tube 1 is engaged with the inner tube 2 or a down-the-hole hammer 4 attached to the distal end side thereof, and is thus configured to advance in the drilling direction while being pulled by the inner tube 2. The proximal end portion of the inner tube 2 is used by being connected to a rotation driving device 3, and the rotation driving device 3 is based on the rotary percussion method in the case of FIG. 1 and rotates with respect to the proximal end of the inner tube 2. A force is applied, which is also transmitted to the tip of the inner tube 2. Further, a down-the-hole hammer 4 is attached to the distal end side of the inner tube 2 so that a striking force is transmitted to the inner tube bit 20 attached to the distal end of the inner tube 2. In the drilling operation, the inner tube bit 20 rotates with the rotation of the inner tube 2 and a striking force is applied to the inner tube bit 20, while the outer tube 1 has a rotational force. And the striking power is never transmitted.
As long as a rotational force around the axis can be applied to the inner tube 2 and a striking force can be applied to the inner tube bit, an appropriate rotational drive device and down-the-hole hammer can be used.

  Further, the pipe body is used for digging while sequentially connecting unit pipe bodies having a predetermined length. Furthermore, in the following example, an example of a double pipe will be described, but another pipe body or flow path is provided in the inner pipe, or another pipe body or flow path is provided between the outer pipe and the outer pipe. It is possible.

(Basic concept of drilling)
In the present invention, as shown in FIG. 1, a down-the-hole hammer 4 is attached to the tip side of the inner tube 2, and an inner-tube bit 20 is provided at the tip of the down-the-hole hammer 4. The down-the-hole hammer 4 includes a piston (not shown) and a leader (not shown). By sending compressed air or pressurized water from the ground, the piston moves up and down and hits the inner pipe bit 20. Drilling (drilling), and the impact energy of the piston is directly transmitted to the inner pipe bit 20, so that there is little transmission loss, and drilling can be efficiently performed even if the ground to be excavated is hard rock or the like. .

  The inner pipe bit 20 has a shape that generates a force that decenters the drilling direction in relation to the drilling reaction force of the ground when drilling with only the impact force by the down-the-hole 4. The tapered shape has a pressure receiving surface inclined with respect to the axial direction of the inner tube 2. By forming this pressure receiving surface (inclined surface), when drilling, the inner tube 2 moves straight due to the rotation and impact force, but with only impact, the ground reaction force (cutting resistance) possessed by the ground. Therefore, a force that decenters the direction of drilling in the direction of the tip of the pressure-receiving surface having an inclined taper is generated, and the bending of the hole is corrected.

  As shown in FIG. 1, the distal end portion of the outer tube 1 may be configured by a surface orthogonal to the drilling direction. As another example, as shown in FIG. 4, the inner tube bit The pressure receiving surface may be composed of a tapered pressure receiving surface similar to that of 20.

  As shown in FIGS. 3 and 6, when a striking force applied by the down-the-hole hammer 4 acts on the inner pipe bit 20, the bit receives a drilling reaction force (cutting resistance) of the ground, and the bit receives a pressure receiving surface (inclined surface). As shown in FIGS. 2 and 5, when drilling, the inner pipe bit 20 is subjected to a rotational force from the base end thereof by the rotational driving device 3 as shown in FIGS. 2 and 5. Therefore, since the relief force is canceled by the rotation of the pressure receiving surface (inclined surface), a straight hole is guaranteed.

  On the other hand, as shown in FIG. 3 and FIG. 6, when correcting the bending of the hole due to drilling, the rotation is performed with the position of the inner pipe bit 20 adjusted so that the tip of the pressure receiving surface (inclined surface) faces in the correction direction. Drilling is performed by applying only the striking force of the down-the-hole hammer 4 without applying the rotational force of the driving device 3. In the case of using the distal end of the outer tube 1 shown in FIG. 6, it is preferable to adjust the distal end portion in advance so as to face the inclined surface in the same direction as the distal end of the inner tube bit 20.

  Thus, the drilling direction can be corrected by continuing the change in the drilling direction for a certain length by hitting with the down-the-hole hammer 4. When the correction of the drilling direction is completed, the above-described linear drilling is performed again.

  As another embodiment, as shown in FIGS. 14 and 15, a tapered outer tube bit 10 having a pressure receiving surface with substantially the same inclination angle as the inner tube bit 20 is provided at the tip of the outer tube 1. Can think. Specifically, the outer tube bit 10 is engaged with the inner tube bit 20 with the outer tube bit 10 aligned with the inclination of the pressure-receiving surface of the inner tube bit 20, and the outer tube bit 20 rotates to rotate the outer tube bit 20. A configuration in which the tube bit 10 is rotated in the same direction can be considered. The outer tube bit 10 and the inner tube bit 20 are engaged with each other by, for example, providing a projection (not shown) on the inner peripheral surface of the outer tube bit 10 and fitting the inner tube bit 20 to the projection. A groove (not shown) is formed so as to extend in the drilling direction (axial direction), and the inner tube bit 20 is formed by the fitting relationship between the protrusion of the outer tube bit 10 and the groove of the inner tube bit 20. The outer tube bit 10 rotates with the rotation of the inner tube bit, but the inner tube bit 20 can be configured not to be interlocked. If the outer tube 1 and the outer tube bit 10 are turned into an even pair and the outer tube bit 10 is configured to be rotatable with respect to the outer tube 1, only the outer tube bit 10 is rotated without rotating the outer tube 1. Can be rotated.

  In the case of the above configuration, when drilling, as shown in FIG. 14, the inner tube bit is rotated by the rotation of the inner tube 2 with the pressure-receiving surfaces of the inner tube bit 20 and the outer tube bit 10 aligned with each other. 20 and the outer pipe bit 10 are rotated, and the straight drilling is performed in a state in which a striking force is applied only to the inner pipe bit 20 by the down-the-hole hammer 4. On the other hand, as shown in FIG. 15, when only the inner pipe bit 20 is struck by the down-the-hole hammer 4, the tip direction of the pressure-receiving surface whose drilling direction is tapered with respect to the drilling reaction force (cutting resistance) of the ground This produces a force that decenters the hole and corrects the bending of the hole. In the configuration having the fitting relationship between the protruding portion of the outer tube bit 10 and the groove of the inner tube bit 20, the outer tube bit 10 is used as a lost bit and separated from the outer tube 1 at the end of the drilling operation. It can also be left in the hole.

  The excavator of the present invention can be used well for a tube installation method for ground stabilization including a tunnel tip receiving method and the like. Specifically, by selecting and adjusting the rotational force around the axis of the inner pipe bit 20 and the striking force by the down-the-hole hammer 4, it is possible to switch between the straight drilling hole and the correction mode of the hole bending. Further, in the ground excavating apparatus according to the present invention, the down-the-hole hammer 4 attached to the distal end side of the inner pipe gives a striking force to the inner pipe bit 20, so that the transmission loss of the striking force is small and the drilling depth is deep. However, there is no possibility that the drilling speed is reduced.

  As shown in FIG. 13, in a top hammer type (rotary percussion type) excavator that applies a striking force to the proximal end side of a conventional inner pipe, it is difficult to transmit the striking force to the bit at the tip. However, in the excavating apparatus of the present invention, the drilling speed is constant even when the drilling depth is increased. Therefore, the drilling efficiency is remarkably superior because the drilling speed does not decrease in proportion to the drilling depth as compared with the conventional excavator.

  At an appropriate point in the drilling process, the outer tube 1 and the inner tube 2 are added. Since the addition itself is a well-known matter, description thereof is omitted.

(Inner pipe bit)
The structure of the inner tube bit 20 will be described below with reference to FIGS.
The inner pipe bit 20 integrated with the tip of the inner pipe 2 by screwing connection or the like has a bottomed cylindrical shape, and the inside becomes a passage for cutting water fed by pressure through the inner pipe 2 and is discharged from the discharge port 24 at the tip. It has become so. A central portion of the tip surface of the inner pipe bit 20 is a pressure surface (inclined surface) 21. A number of bit blades 22 are integrated at an appropriate position on the distal end surface. Furthermore, drainage grooves 25, 25 accompanying cutting are formed on the outer peripheral surface. The proximal end portion of the inner tube bit 20 is connected to the down-the-hole hammer 4 and is configured to be internally installed in the outer tube 1.

(Example of grasping the rotation angle)
When correcting the drilling direction, it is particularly important to grasp the angle of the inner pipe bit 20 at each time point. Therefore, for example, if the form shown in FIG. 10 is adopted, it can be grasped even after the pipes are added. That is, a rotation angle detector 40 such as a rotary encoder is provided in the rotary head 3 </ b> A of the rotary drive device 3. In FIG. 10, the down-the-hole hammer 4 is not shown.

  The current position of the inner tube bit 20 is set initially or at an appropriate time. In the stage of (a) of FIG. 10, it is in a zero reset state. When the drilling for one tube is completed, as shown in FIG. 5B, the outer tube 1 is gripped by the outer tube chucking 4A, and the rotary head 3A is rotated in the reverse direction. Disconnect. In this case, the rotation angle direction of the rotary head 3A is not a problem. Subsequently, as shown in (c), the inner tube 2 is gripped by the inner tube chucking 4B, and the rotary head 3A is separated from the inner tube 2. At that time, a rotation angle (for example, 180 degrees) at the time when the inner tube 2 is gripped by the inner tube chucking 4B is stored in the rotation angle detector 40. The rotational angle azimuth of the rotary head 3A after separation does not matter. Next, as shown in (d), a new inner pipe is brought in and connected to the previous inner pipe. Thereafter, as shown in (e), the rotary head 3A is rotated until the rotation angle (for example, 180 degrees) stored in the rotation angle detector 40 is reached, and the position of the inner tube head 20 is set. Subsequently, the newly introduced outer tube is connected to the previous outer tube.

(Example of drilling with hole bending detection)
An appropriate detector can be employed for detecting the hole bending. For example, a mechanical gyroscope or a magnetic compass can be used for bending in the horizontal direction, and an inclinometer, a hydraulic pressure difference meter, or the like can be used for bending in the vertical direction.

  Therefore, in the example shown in FIG. 11, an inclinometer 51 is provided at the distal end portion of the inner tube 2 so that a signal in the vertical direction passes through the tube and is taken out of the tube (a signal transmission system is not shown). On the other hand, the gyro 52 is inserted in order to detect hole bending in the horizontal direction. In FIG. 11, the down-the-hole hammer 4 is not shown.

  The construction method will be described in order. As shown in FIG. 11 (a), the straight hole drilling by the double pipe rotary percussion is continued, and when the drilling for an appropriate length is completed, the rotation of the rotary drive device 3 is rotated. The gyro 52 is separated from the head 3A, and the gyro 52 is inserted into the inner tube 2 from the proximal end of the inner tube 2 to the distal end as shown in (b), and the position of the distal end is detected. When the position detection is completed, the gyro 52 is pulled out as shown in FIG. Thereafter, as shown in (d), the outer tube 1 and the inner tube 2 (inner tube) based on the horizontal position of the gyro 52 and the vertical position signal from the inclinometer 51 with the tube connected to the rotary head 3A. After correcting the circumferential position of the head 20), propulsion by striking force is performed as shown in (e). In the following, as shown in (f), the insertion of the gyro 52 and the pipe line measurement, the straight drilling, the azimuth correction drilling, etc. are appropriately combined to perform drilling to the target length. When the final drilling is completed, the inner tube 2 is removed as shown in (g), and the outer tube 1 is left as a receiving tube.

  In this drilling example, when the orientation detector such as the gyro 52 is inserted and retracted, for example, the form shown in FIG. 12 can be adopted. That is, an orientation detector such as a gyro 52 is housed in a case 53 in a substantially liquid-tight state in the inner tube 2, the retreat is connected to a reel winder 54, and a hose of a pump 55 is placed in the inner tube 2. Make 56 ports communicate. When water is supplied from the pump 55 through the hose 56, the case 53 can be pushed forward. At the time of retreat, it can be retracted by pulling in with the reel winder 54.

It is explanatory drawing of a drilling system. It is a schematic diagram of a linear drilling state. It is a hole bend correction drilling state schematic diagram. It is explanatory drawing of the drilling system using the front-end | tip part of another outer tube | pipe. It is a schematic diagram of the straight hole drilling state. It is the hole bend correction drilling state outline figure. It is a longitudinal cross-sectional view of an inner tube bit. It is the side view. It is a side view of an outer tube tip and an inner tube bit. It is explanatory drawing of the connection of a tubular body, and rotation angle detection. It is explanatory drawing of the example of drilling which uses a hole bending detection together. It is explanatory drawing of the example of insertion of an azimuth | direction detector, and a retracting apparatus. It is a graph of drilling depth-speed of the excavator of the present invention and the conventional excavator. It is a schematic diagram of the linear drilling state of the Example which attached the outer pipe | tube bit to the front-end | tip part of an outer pipe | tube. It is the hole bend correction drilling state outline figure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Outer pipe | tube, 2 ... Inner pipe | tube, 3 ... Rotary drive device, 3A ... Rotary head, 10 ... Outer pipe bit, 20 ... Inner pipe bit, 21 ... Inclined surface, 24 ... Discharge port, 51 ... Inclinometer, 52 ... gyro.

Claims (9)

The outer pipe, the inner pipe, the down-the-hole hammer attached to the tip side of the inner pipe, and the tip of the down-the-hole hammer are attached to the tip of the down-the-hole hammer. This is a method of installing a pipe for ground stabilization in the ground using an excavator equipped with an inner pipe bit that generates a force that decenters the drilling direction in relation to the drilling reaction force. And
In the case of linear drilling, drilling while giving the inner pipe bit a rotational force around the axis and a striking force by the down-the-hole hammer,
When correcting the hole bending associated with the hole drilling, the hole drilling is performed only with the striking force of the inner pipe bit,
After the above-mentioned drilling hole is drilled to a target length, the outer pipe is left in the ground to form a pipe for ground stabilization, which is a tube installation method for ground stabilization.   2. The pipe installation method for stabilizing a ground according to claim 1, wherein the inner pipe bit has a tapered shape having a pressure receiving surface inclined with respect to the axial direction of the inner pipe. An outer pipe bit is attached to the tip of the outer pipe,
The outer tube bit has a tapered shape having a pressure receiving surface with substantially the same inclination angle as the inner tube bit, and is configured to rotate in the same direction by the rotation of the inner tube bit by engaging with the inner tube bit. And
In the case of straight drilling, the inner pipe bit and the outer pipe bit are rotated with the inclination of the pressure receiving surfaces of the inner pipe bit and the outer pipe bit aligned, and a striking force is applied to the inner pipe bit to perform drilling.
3. The ground stabilization pipe body installation method according to claim 2, wherein the hole bending is performed only by the striking force of the inner pipe bit when correcting the hole bending accompanying the hole drilling. The outer tube, the inner tube, the down-the-hole hammer attached to the tip of the inner tube, and the down-the-hole hammer attached to the tip of the down-the-hole hammer. Using an excavator equipped with an inner pipe bit shaped to generate a force that decenters the drilling direction in relation to the drilling reaction force, along the tunnel line above the tunnel cross section and prior to tunnel excavation A pre-construction method to build a pipe body,
In the case of linear drilling, drilling while giving the inner pipe bit a rotational force around the axis and a striking force by the down-the-hole hammer,
When correcting the hole bending associated with the hole drilling, the hole drilling is performed only with the striking force of the inner pipe bit,
A tunnel tip receiving method characterized in that, after the above-mentioned drilling hole is drilled to a target length, the outer pipe is left in the ground to form a pipe for stabilizing the ground.   The tunnel inner receiving method according to claim 4, wherein the inner pipe bit has a tapered shape having a pressure receiving surface inclined with respect to the axial direction of the inner pipe. An outer pipe bit is attached to the tip of the outer pipe,
The outer tube bit has a tapered shape having a pressure receiving surface with substantially the same inclination angle as the inner tube bit, and is configured to rotate in the same direction by the rotation of the inner tube bit by engaging with the inner tube bit. And
In the case of straight drilling, the inner pipe bit and the outer pipe bit are rotated with the inclination of the pressure receiving surfaces of the inner pipe bit and the outer pipe bit aligned, and a striking force is applied to the inner pipe bit to perform drilling.
6. The tunnel tip receiving method according to claim 5, wherein when correcting the hole bending accompanying the hole drilling, the hole drilling is performed only by the striking force of the inner pipe bit. The outer pipe, the inner pipe, the down-the-hole hammer attached to the tip side of the inner pipe, and the tip of the down-the-hole hammer are attached to the tip of the down-the-hole hammer. An inner pipe bit having a shape that generates a force that decenters the drilling direction in relation to the drilling reaction force,
In the case of linear drilling, drilling while giving the inner pipe bit a rotational force around the axis and a striking force by the down-the-hole hammer,
At the time of correcting the hole bending accompanying the drilling, it was configured to perform drilling only with the striking force by the inner pipe bit,
Drilling rig characterized by that.   The excavator according to claim 7, wherein the inner pipe bit has a tapered shape having a pressure receiving surface inclined with respect to an axial direction of the inner pipe. An outer pipe bit is attached to the tip of the outer pipe,
The outer tube bit has a tapered shape having a pressure receiving surface with substantially the same inclination angle as the inner tube bit, and is configured to rotate in the same direction by the rotation of the inner tube bit by engaging with the inner tube bit. And
In the case of straight drilling, the inner pipe bit and the outer pipe bit are rotated with the inclination of the pressure receiving surfaces of the inner pipe bit and the outer pipe bit aligned, and a striking force is applied to the inner pipe bit to perform drilling.
The excavation apparatus according to claim 8, wherein the drilling is performed only by the striking force of the inner pipe bit when correcting the hole bending accompanying the drilling.

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