JPH0925787A - Updating method for existing underground pipe and updating excavator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the loosening and collapse of the natural ground by installing a new underground pipe in the space formed at the inner diameter portion of an existing underground pipe in updating the existing underground pipe. SOLUTION: A disk cutter 6 is rotated, the concrete 1b portion on the inner diameter side from the reinforcing bars 1c, 1d of an existing underground pipe 1, and an inner peripheral face 1e is formed and finished by a bit 7. Rollers 18 of a guide means 20 fitted via a circular body 17 are rolled on the inner peripheral face 1f of the existing underground pipe 1, a cutter head 5 and a leading pipe 3 are guided along the inner peripheral face 1f of the existing underground pipe 1, and the disk cutter 6 and the bit 7 accurately guide the position of the cutter head 5 against the inner diameter face of the existing underground pipe 1. A new underground pipe 25 is advanced to the installation space formed at the concrete 1b portion located on the inner diameter side from the reinforcing bars 1c, 1d of the existing underground pipe 1, a filler is filled in the filler space 26 between the inner peripheral face 1e of the existing underground pipe 1 serving as the installation space of the new underground pipe 25 and the outer diameter section of the new underground pipe 25, and the new underground pipe 25 is fixed to the existing underground pipe 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for renewing an existing buried pipe that replaces an aged old buried pipe with a new buried pipe, and an excavator for the renewal.

[0002]

2. Description of the Related Art A buried pipe such as a concrete pipe buried in an old age has cracks or brittleness when deteriorated, and water leakage occurs due to deterioration of a joint portion. In such cases, it is necessary to replace the existing buried pipe with a new buried pipe. As a repair method in that case, a method of attaching a film to the inner surface of the already buried pipe or attaching a lining has been attempted.

In addition, when renewing to a new buried pipe, many methods of completely removing the existing buried pipe and replacing it with a new buried pipe have been proposed, but for renewing the existing buried pipe used in this case. As a first conventional technique relating to the excavator, an invention disclosed in Japanese Patent Laid-Open No. 2-54094 has been proposed. As shown in FIG. 4, this technique is based on the existing pipe 50 that has deteriorated.
Vertical shafts 52 and 63 are provided at both ends of the vertical pipe 52, one end of the vertical pipe 52 is connected to one end of the existing pipe 50, and the bottom surface has the same diameter as that of the existing pipe 50. The cemented carbide reamer 51 that has been welded and made into a file is brought into contact.
A rotary shaft 53 of a fixed length is fixed to the rear end of the carbide reamer 51, and the fixed length rotary shaft 53 is sequentially connected to the shaft 63 side.
The rotating force of the driving machine 58 equipped on the vertical shaft 52 is applied to the carbide reamer 5
Transmit to 1. Carbide reamer 51, which is given a rotating force,
The concrete wall surface of the existing pipe 50 is crushed and removed by the unevenness of the surface. The steel material arranged in the concrete is a file of superhard steel 51-
It is cut by a. The crushed and cut concrete and steel pieces are taken in through a plurality of slits 52 provided in the cutting portion of the cemented carbide reamer 51. Inside the carbide reamer 51 and the rotary shaft 53, a screw 54 for rotatably incorporating the existing pipe piece taken in from the slit 52 to the vertical shaft 52 side is rotatably incorporated. In addition, a guide device 55 having arms in four directions is provided at the tip of the carbide reamer 51 in order to prevent crushing of the existing pipe 50 and blurring during cutting.
It is installed inscribed in 0 and holds the center.

Next, the operation of FIG. 4 will be described. A penetration ring 56 having a diameter slightly larger than the outer diameter of the existing pipe 50 is installed on the outer peripheral portion of the cemented carbide reamer 51, and a new pipe 61 having substantially the same diameter as the existing pipe 50 is fitted at the rear end thereof. 51
It is inserted so as to cover the existing pipe 50 while preventing the ground from collapsing. At this time, the insertion of the penetrating ring 56 and the crushing and cutting of the cemented carbide reamer 51 are performed at the same time, and the insertion speed of the penetrating ring 56 and the crushing and cutting of the cemented carbide reamer 51 are the same as those of the propulsion device 57 installed in the vertical shaft 52. The mechanism is such that the insertion progresses in tandem. In this way, the crushing of the concrete due to the unevenness of the cemented carbide reamer 51, the cutting of the steel material with the file-like superhard steel 51-a, and the insertion of the new pipe 61 are sequentially performed, and the replacement method of the new pipe 61 is completed. To do.

As a second conventional technique relating to the excavator for renewing an already buried pipe, the invention disclosed in Japanese Patent Application Laid-Open No. 1-198993 is proposed. As shown in FIG. 5, this technique cuts the existing pipe 72 extending from the first shaft 78 to the second shaft 80, and renews the existing pipe line by laying a new pipe 74 at the trace. Is a device for cutting the existing pipe 72 while advancing from the first vertical shaft 78 toward the second vertical shaft 80, and includes a slider 92 that slides along the inner diameter of the existing pipe 72. The propulsion type excavator 82 provided in the front part and the liquid discharged from the first liquid pump 93 are supplied from the supply pipe 96 to the excavator 82 via the inner diameter portion of the existing pipe 72, and the excavator 82 moves into the existing pipe 72. The excavator transporting device that discharges to the processing device 98 via the disposed discharge pipe 86, the second liquid pump 87, and the return pipe 89, and the excavator 82 installed in the first shaft 78.
And a propulsion device for propelling the new pipe 74 to the excavation mark.

Next, the operation of FIG. 5 will be described. First
The existing pipe 7 extending from the vertical shaft 78 to the second vertical shaft 80
2 is cut by a cutter bit 94 of a propulsion type excavator 82 guided by a slider 92 sliding along the inner diameter of the existing pipe 72. In the cut excavated material of the existing pipe 72, the liquid discharged from the first liquid pump 95 is supplied from the second vertical shaft 80 side to the excavator 82 via the liquid supply pipe 96 and the inner diameter portion of the existing pipe 72. The liquid for transporting the excavated material is disposed in the existing pipe 72 so as to extend to the second shaft 80, and the return pipe 8 from the second liquid pump 87.
It is discharged to the processing unit 98 on the ground via the line 9. In the excavation mark thus excavated, the new pipe 74 is arranged by the slider 91 which is driven by the propulsion jack 92 of the propulsion device 84 installed in the first shaft 78 and slides on the base 88. To be done.

As a third conventional technique, a propulsion device or a pulling machine installed in a shaft excavated at a predetermined distance is used.
The method of pushing out the existing buried pipe from the soil or pulling it out from the soil and then propelling the existing pipe is also partially adopted.

[0008]

However, both the above-mentioned first conventional technique and the second conventional technique are related to the existing pipe 5.
After cutting and removing all 0 and 72, new pipes 61 and 74
Since it is the method of laying the cemented carbide reamer 51 and the cutter bit 94, it not only lowers the durability of the cemented carbide reamer 51 and the cutter bit 94 but also takes a lot of time to dispose of a large amount of waste material generated from the existing pipes 50 and 72, and newly installed pipes There was a problem in stabilizing the ground around 74. In particular, in the first conventional technique, the cemented carbide reamer 51 is a method of crushing concrete due to unevenness and cutting of reinforcing bars with the file-like superhard steel 51-a. However, there is a problem in that the durability of the cemented carbide reamer 51 is reduced because the reinforcing bars in the concrete are cut. Also,
In the second conventional technique, the new pipe 74 is inevitably larger in diameter than the existing pipe 72, and the new pipe 74 has the same diameter as the existing pipe 72.
There was a problem that could not be laid. As a third conventional technique, it takes a lot of man-hours to excavate a vertical shaft at a predetermined distance, and since the already buried pipe and the soil are in close contact with each other, the already buried pipe is pushed out or extracted from the soil. There was a problem that a large force was required and the existing buried pipe was damaged.

The present invention has been made for the purpose of providing a method of renewing an already buried pipe and an excavator for renewing the same in order to solve the problems in the above-mentioned conventional techniques.

[0010]

In order to achieve the above-mentioned object, the method for updating an already buried pipe according to the present invention is the method for updating an already buried pipe in which an already buried pipe is replaced with a new buried pipe. It comprises a step of forming an installation space for the new buried pipe in the inner diameter portion and a step of installing the new buried pipe in this space. When the already buried pipe is a buried pipe with a reinforcing bar, it comprises a step of forming an installation space for a new buried pipe in the inner diameter part of the already buried pipe inside the reinforcing bar, and is formed in the inner diameter part of the already buried pipe. The process of injecting the filler into the gap between the installation space of the new buried pipe and the outer diameter of the new buried pipe, Is formed with reference to the inner diameter surface of the.

The excavator for renewing an already buried pipe according to the present invention is
A cutter head has a cutter only on the outer peripheral part of the front plate, and this cutter forms an installation space for the new buried pipe in the inner diameter part of the existing buried pipe, and is installed behind this cutter head and excavated by the cutter head. And means for discharging the excavated scrap powder. The guide means is installed in the front part of the cutter head and is guided to the inner diameter surface of the existing pipe, and comprises sealing means installed in front of the cutter head. It is composed of a lubricant outlet for reducing the frictional force with the inner circumference of the installation space of the new buried pipe formed in the inner diameter part of the.

[0012]

According to the above construction, the following operation is performed. The method of renewing an already buried pipe according to the present invention is a method of forming an installation space for a newly buried pipe in an inner diameter portion of the already buried pipe, and installing the newly buried pipe in this space. Since there is no change between the ground and the ground, problems such as looseness and collapse of the ground can be solved. When the already buried pipe is a buried pipe with a reinforcing bar, if a space for installing a new buried pipe is formed in the inner diameter portion of the existing buried pipe inside the reinforcing bar, it is not necessary to cut the reinforcing bar. It can be easily formed. If the filler is injected into the gap between the installation space of the new buried pipe and the outer diameter of the new buried pipe formed in the inner diameter portion of the already buried pipe,
The new buried pipe can be easily fixed to the existing buried pipe.
If the installation space for the new buried pipe is formed in the inner diameter portion of the existing buried pipe with reference to the inner diameter surface of the existing buried pipe, the installation space for the new buried pipe can be easily formed.

An excavator for renewing an already buried pipe according to the present invention is
The cutter installed only on the outer peripheral part of the front plate of the cutter head cuts the inner diameter of the existing buried pipe to form the installation space for the new buried pipe, and the cutting dust excavated by the cutter head is located behind the cutter head. It is discharged by the installed excavation scrap powder discharging means. Since the guide means installed in the front portion of the cutter head is guided to the inner diameter surface of the already buried pipe, the position of the cutter head with respect to the inner diameter surface of the already buried pipe can be set accurately and easily. By the sealing means installed in front of the cutter head, the lubricant can be held on the front surface of the cutter head and the sewage in front of the cutter head which invades in the direction of the cutter head can be sealed. Further, the lubricant supplied from the lubricant discharge port reduces the frictional force between the outer circumference of the leading conduit and the inner circumference of the installation space of the new buried pipe formed in the inner diameter portion of the existing buried pipe.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for updating an already buried pipe and an excavator for updating the same according to the present invention will be described in detail below with reference to FIGS. 1 is a side sectional view of an excavator for renewal of an already buried pipe according to the present invention, FIG. 2 is a view showing one detail of FIG. 1, (A) is a Z arrow view of FIG. 1, and (B) is FIG. FIG. 3 is a cross-sectional view taken along the line AA of FIG. 3, and FIG. 3 is a view showing a method of updating an existing buried pipe according to the present invention and an updated existing buried pipe constructed by the updating machine.

1 and 2, the joint portion 1
The existing buried pipe 1 connected by a is composed of a reinforcing bar 1c arranged in the concrete 1b and parallel to the axis of the existing buried pipe 1, and a circular reinforcing bar 1d connecting the reinforcing bars. In the embodiment of the present invention, when the existing buried pipe 1 is deteriorated, a new buried pipe such as a vinyl chloride pipe is installed in the installation space of the new buried pipe formed in the inner diameter portion of the existing buried pipe 1 so that the existing buried pipe is installed. 1 is updated.

The structure of the excavator for updating the existing buried pipe used for updating the existing buried pipe 1 will be described below. Convex spherical surface portion 2b formed at the tip of the case 2a of the screw conveyor 2
And the concave spherical surface portion 3c formed at the tip of the rear front conduit 3b, the front front conduit 3a is swingably supported, and the front front conduit 3a is rotatably supported by the bearing 4. The attached cutter head 5 is the screw conveyor 2
Is driven to rotate. In this way, the front leading conduit 3a and the rear leading conduit 3b constitute the leading conduit 3. A front plate (not shown) is fixed to the front end of the cutter head 5, and the rebar 1 that constitutes the existing buried pipe 1 is fixed to the front plate.
A disc cutter 6 for cutting the concrete 1b portion on the inner diameter side of c and 1d, and a bit 7 for finishing the inner peripheral surface 1e of the already buried pipe 1 cut by the disc cutter 6 are mounted.

The screw conveyor 2 includes the case 2a.
Is connected at the center of the spherical portion 2b by a swingable universal joint 2c, and the front joint 3a and the cutter head 5 are swingable by this universal joint 2c. The front tip conduit 3a and the cutter head 5 seal the lubricating oil of the bearing 4 and the external concrete dust powder by three kinds of seals 8. Front tip conduit 3a
A rocking cylinder 9 of the front tip conduit 3a and a stroke sensor 10 for detecting the rocking angle thereof are pivotally mounted between and the case 2a of the screw conveyor 2. The position of the front conduit 3 with respect to the natural ground is the case 2a of the screw conveyor 2 where the laser beam 11 emitted from a vertical shaft (not shown) is used.
It is detected when the laser light receiver 12 attached to the optical receiver receives the light. In addition, the outer peripheral portion of the rear tip conduit 3b and the existing buried pipe 1
In order to slide the cutting inner peripheral surface 1e smoothly, a lubricant outlet 13 is provided on the outer peripheral portion of the rear tip conduit 3b.

A shaft 15 having a lubricant outlet 14 is fixed to the center of the front surface of the cutter head 5, and an annular body 17 is rotatably mounted on the shaft 15 via a bearing 16. An arm 19 is fixed to the front end of the annular body 17, and a roller 18 that rolls on the inner peripheral surface 1f of the existing buried pipe 1 is rotatably mounted on the arm 19. The roller 18 and the arm 19 constitute a guide means 20 for the leading conduit 3 and the cutter head 5. This guide means 20 has three arms 19 having an angle of 120 degrees, as shown in detail in FIG.
Each roller 18 rolling on the inner peripheral surface 1f of the existing buried pipe 1 is rotatably attached to the tip of the roller. In addition, arm 1
A water stop 22 that slides on the inner peripheral surface 1f of the existing buried pipe 1 is fixed to the center of the front end of 9 via a rod 21, and the sealing means 23 is formed by the rod 21 and the water stop 22. It is configured. In FIG. 2B, a cutting inner peripheral surface 1e of an already buried pipe 1 formed by a disk cutter 6 mounted on the cutter head 5 and a bit 7, and a new cutting inner peripheral surface 1e installed inside the cutting inner peripheral surface 1e. A ring-shaped filler space 26 is formed between the outer peripheral portions of the buried pipe 25 to fill the filler for fixing the new buried pipe 25 to the existing buried pipe 1.

Next, the excavation operation of the excavator for renewal of the already buried pipe 1 will be described with reference to FIGS. 1 and 2. The cutter head 5, which is rotatably attached to the front tip conduit 3a, is rotationally driven by the screw conveyor 2, and thrust is applied via the screw conveyor 2 by a known propulsion device installed in a vertical shaft (not shown). It should be noted that the thrust applied to the cutter head 5 is not limited to the screw conveyor 2, but is installed in a shaft (not shown) via the case 2a of the screw conveyor 2 and the front tip conduit 3a, or the new buried pipe 25 and the tip conduit 3. It may be provided by a known propulsion device, or they may be used in combination.

When the cutter head 5 is rotated while the disk cutter 6 mounted on the front plate of the cutter head 5 is pressed against the concrete 1b portion on the inner diameter side of the reinforcing bars 1c and 1d of the existing buried pipe 1, the disk cutter 6 is rotated. Rotates to cut the concrete 1b portion on the inner diameter side of the reinforcing bars 1c and 1d of the already buried pipe 1 to form the inner peripheral surface 1e of the already buried pipe 1. The cutting inner peripheral surface 1e of the existing buried pipe 1 is further finished by a bit 7 mounted on the front plate of the cutter head 5. The concrete dust powder of the concrete 1b portion excavated by the disc cutter 6 and the bit 7 is the screw conveyor 2 installed at the rear of the cutter head 5.
Is discharged to the rear by. Further, since the seal member 28 is provided, the concrete dust powder is prevented from accumulating on the lower portion of the already buried pipe 1 and the roller 18 is prevented from riding on the concrete dust powder. The seal member 28 may not be provided if necessary.

The cutter head 5 and the front tip conduit 3a are
The spherical surface 2b of the case 2a and the spherical surface 3c of the rear tip conduit 3b are swingably attached to the case 2a and the rear tip conduit 3b of the screw conveyor 2 and to the screw conveyor 2 by a universal joint 2c. It is rockably driven by the moving cylinder 9. The swing angle of the cutter head 5 and the front tip conduit 3a is detected by the stroke sensor 10. Also, the position of the front conduit 3 with respect to the ground is
A laser beam 11 emitted from a well-known shaft not shown is
The laser light receiver 12 attached to the case 2a of the screw conveyor 2 receives the light and detects it. Tip conduit 3
With the lubricant discharged from the lubricant discharge port 13 installed on the outer peripheral portion of the front pipe 3, the friction between the outer peripheral portion of the front conduit 3 and the inner cutting surface 1e of the existing buried pipe 1 is reduced to smoothly move the front conduit 3. It can be promoted.

The guide means 20 mounted via the annular body 17 rotatably mounted on the shaft 15 fixed to the center of the front face of the cutter head 5 has the roller 18 rotatably mounted on its arm 19. 2A, the inner peripheral surface 1f of the existing buried pipe 1 rolls. Therefore,
Since the cutter head 5 and the leading conduit 3 are guided along the inner peripheral surface 1f of the already buried pipe 1, the disc cutter 6 and the bit 7 are prevented from coming into contact with the reinforcing bars 1c and 1d constituting the already buried pipe 1. The position of the cutter head 5 with respect to the inner diameter surface of the already buried pipe 1 can be accurately and easily guided.

The lubricant discharged from the lubricant discharge port 14 of the shaft 15 fixed to the front surface of the cutter head 5 through a lubricant supply passage (not shown) in the screw conveyor 2 is a water stop of the sealing means 23. Since it is held on the front surface of the cutter head 5 by 22, the concrete 1b portion of the existing buried pipe 1 can be smoothly cut by the disk cutter 6 and the bit 7. In addition, it has an effect of making the cut concrete dust powder float and easily discharged from the screw conveyor 2. Moreover, since the sewage in front of the existing buried pipe 1 does not enter the cutter head 5 by the water stop 22 of the sealing means 23, the construction can be continued even if the sewage exists in the existing buried pipe 1.

Referring to FIG. As described above, in the installation space of the new buried pipe 25 formed in the concrete 1b portion located on the inner diameter side of the reinforcing bars 1c and 1d forming the already buried pipe 1 connected by the joint portion 1a, a vertical shaft (not shown) is provided. When the new buried pipe 25 made of vinyl chloride or the like is propelled by a known propulsion device installed in the inside, the inner peripheral surface 1e of the existing buried pipe 1 and the outside of the new buried pipe 25 are used as the installation space for the new buried pipe 25. The space 26 for the filler between the diameter portions is filled with the filler to fix the new buried pipe 25 to the existing buried pipe 1.
The new inner peripheral surface 25a of the new buried pipe 25 may be the same as the inner peripheral surface 1f of the existing buried pipe 1. In the above embodiments, the existing buried pipe 1 has been described as a concrete pipe with a reinforcing bar, but it may be a concrete pipe without a reinforcing bar, or a vinyl chloride pipe or an iron pipe, the cutter of which the inner diameter portion can be cut. It goes without saying that the installation space for the new buried pipe can be formed by the above and can be replaced with a predetermined new buried pipe.

[0025]

As described above, the method of updating an already buried pipe and the excavator for updating the same according to the present invention have the following effects. (1) The method of renewing an already buried pipe according to the present invention is a method of installing a new buried pipe in a space formed in an inner diameter portion of the already buried pipe, and between the outer diameter portion of the already buried pipe and the ground. Since there is no change, problems such as looseness and collapse of the ground can be reliably solved. (2) Since the inner diameter of the new buried pipe can be made almost the same as the inner diameter of the existing buried pipe, it can be used with exactly the same specifications as the existing buried pipe, and the new buried pipe is installed inside the already buried pipe. Therefore, even a vinyl chloride pipe or the like has a sufficient load bearing capacity against earth pressure. (3) When the existing buried pipe is a buried reinforcing pipe, if the space for installing the new buried pipe is formed in the inner diameter part of the existing buried pipe inside the reinforcing bar, it is not necessary to cut the reinforcing bar. The durability can be greatly improved and the construction becomes easy. Further, since only concrete is scraped off, it is easy to discharge concrete waste powder. (4) If the filler is injected into the gap between the installation space of the new buried pipe formed in the inner diameter of the existing buried pipe and the outer diameter of the new buried pipe, the new buried pipe can be easily fixed to the existing buried pipe. You can (5) If the installation space for the new buried pipe is formed in the inner diameter portion of the existing buried pipe with the guide means installed in the front part of the cutter head as the reference, the new buried area for the existing buried pipe The position of the tube can be formed reliably and easily.

(6) Since a normal excavator and cutter head can be partially modified to be a renewal excavator that cuts the inner diameter portion of an existing buried pipe to form a space for installing a new buried pipe, The cost of the conduit and cutter head is reduced. (7) By the sealing means installed in front of the cutter head, the lubricant can be held on the front face of the cutter head, so that the cutter can smoothly cut the existing buried pipe, and the concrete scrap powder cut by the lubricant is suspended. It can be easily discharged. Further, since the sewage that enters in the direction of the cutter head can be sealed, the existing buried pipe can be renewed even if sewage exists. (8) The frictional force is reduced by the lubricant supplied between the outer circumference of the leading conduit and the inner circumference of the installation space of the new buried pipe formed in the inner diameter portion of the existing buried pipe, and the frictional force is formed in the inner diameter portion of the existing buried pipe. The new buried pipe can be installed smoothly in the designated space.

[Brief description of drawings]

FIG. 1 is a side sectional view of an excavator for renewing an already buried pipe according to the present invention.

2 is a diagram showing the detail of FIG. 1, in which (A) is a Z arrow view of FIG. 1 and (B) is a sectional view taken along the line AA of FIG.

FIG. 3 is a diagram showing a method for updating an existing buried pipe according to the present invention and an updated existing buried pipe constructed by the updating machine.

FIG. 4 is a diagram showing a first conventional technique.

FIG. 5 is a diagram showing a second conventional technique.

[Explanation of symbols]

 1 Existing Pipe 1a Joint Part 1b Concrete 1c, 1d Reinforcing Bars 1e, 1f Inner Surface 2 Screw Conveyor (Drilling Powder Discharging Means) 2a Case 2b Convex Spherical Part 2c Universal Joint 3 Leading Pipe 3a Front Leading Pipe 3b Rear Leading Pipe 3c concave spherical surface 4 bearing 5 cutter head 6 disc cutter 7 bit 8 seal 9 rocking cylinder 10 stroke sensor 11 laser light 12 laser receiver 13, 14 lubricant discharge port 15 shaft 16 bearing 17 annular body 18 roller 19 arm 20 guide Means 21 Rod 22 Water stop 23 Sealing means 25 New buried pipe 26 Space for filler 28 Sealing member

Claims (8)

[Claims] 1. A method of updating an existing buried pipe to replace the existing buried pipe with a new buried pipe, the step of forming a space for installing the newly buried pipe in an inner diameter portion of the already buried pipe, and installing the newly buried pipe in this space. A method of renewing an existing buried pipe, which comprises the steps of: 2. The method for renewing an existing buried pipe according to claim 1, wherein when the existing buried pipe is a buried reinforcing pipe, a new buried pipe is installed in an inner diameter portion of the existing buried pipe inside the reinforcing bar. A method for renewing an existing buried pipe, which comprises the step of forming a space. 3. The method for renewing an already buried pipe according to claim 1, wherein a filler is injected into a gap between an installation space of the newly buried pipe formed in an inner diameter portion of the already buried pipe and an outer diameter of the newly buried pipe. A method for renewing an existing buried pipe, which comprises the steps of: 4. The method for renewing an already buried pipe according to claim 1, wherein the step of forming a space for installing a newly buried pipe in an inner diameter portion of the already buried pipe is formed with reference to an inner diameter surface of the already buried pipe. A method of updating an existing buried pipe, which is characterized in that 5. A cutter is provided only on the outer peripheral portion of the front plate,
A cutter head that forms a space for installing a new buried pipe in the inner diameter portion of the existing buried pipe by this cutter, and a cutting waste that is installed behind this cutter head and that discharges the cutting dust powder excavated by the cutter head. An excavator for renewing an existing buried pipe, characterized by comprising a powder discharging means. 6. The excavator for renewing an already buried pipe according to claim 5, further comprising guide means installed at a front portion of the cutter head and guided by an inner diameter surface of the already buried pipe. An excavator for renewing existing buried pipes. 7. The excavator for renewing an already buried pipe according to claim 5 or 6, further comprising a sealing means installed in front of the cutter head. . 8. The excavator for renewing an already buried pipe according to any one of claims 5 to 7, wherein the outer circumference of the leading conduit and the inner circumference of an installation space of a new buried pipe formed in an inner diameter portion of the already buried pipe. An excavator for renewal of an already buried pipe, characterized by comprising a lubricant outlet for reducing frictional force.