KR20060035455A - Method for replacing laid pipe underground - Google Patents

Abstract

The present invention relates to a method of replacing buried pipes, a digging step of forming a work tool by digging at a predetermined interval so that the old pipe embedded in the ground in the old pipe replacement section is exposed, and a portion exposed by the work tool of the old pipe. Cutting and forming a leaking part in each of the separated old pipes to connect the internal space of the old pipe and the ground; and leaking a friction reducing agent in suspension in the ground through the leaking part. A first frictional force reducing step of reducing frictional force between the surface of the soil and the earth and sand of the ground; and repeatedly removing the old pipe by moving the old pipe in the longitudinal direction to draw the tip to the work tool and cutting it. . Therefore, the excavation area can be minimized to minimize the construction cost, time and road occupation and control, thereby reducing the causes of traffic jams and traffic accidents.In addition, it is possible to simultaneously remove old pipes and install new facilities in units between work areas. In addition, when the old pipe is removed and the new pipe is buried at the same time, it is possible to prevent other underground facilities located nearby from being damaged, and even if there is a river or a ground building in the middle, it can be carried out without a separate upfront process.

Old pipe, fuse, buried, replacement, reduced friction, bentonite, non-removable

Description

Method for replacing laid pipe underground}

1 is a schematic cross-sectional view showing a trench state for replacing an embedded old pipe according to an embodiment of the present invention.

Figure 2 is a perspective view showing that the perforation is formed in the tube shown in Figure 1;

Figure 3 is a schematic cross-sectional view showing a buried pipe replacement state according to an embodiment of the present invention.

Figure 4 is a flow chart illustrating a method of replacing buried pipe according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

11: Underground 13: Old House

15-1, 15-2. 15- (N-1), 15-N: 1st to Nth working tool

17: perforation 19: fuse

The present invention relates to a buried pipe replacement method, and in particular, a buried pipe replacement method that can be carried out at the same time to remove the old pipe buried in the underground gang and buried new pipe using a non-adhesive method. It is about.

Usually. Water and sewage pipes, oil pipes, gas pipes, and telecommunication pipes made of metal or synthetic resin are mostly embedded in underground gangs. Various pipes buried in the ground are aged, such as corrosion, cracking or breakage in the interior and exterior of the pipe depending on the fluid flowing along the pipe or acidified soil over time. In particular, when burying the pipes without considering the relationship between the depth of buried depth and the load of the load (loads applied by the volume and the vehicle at the top of the buried pipe) or when the maintenance of the buried pipe is poor, do.

If the buried pipe is aging in the above, in the case of water pipes, not only waste due to leakage occurs, but also drinking water is contaminated, and in the case of sewage pipes, the surrounding soil and groundwater are contaminated by waste water. . In addition, in the case of gas pipes, the gas leaks to cause an explosion accident, and in the case of oil pipes, oil leaks to contaminate surrounding soil and groundwater. In the case of a telecommunication tube, groundwater flows through a siliceous or damaged part, causing an expensive communication cable to be damaged, thereby causing loss of communication.

Therefore, old pipes that have been in the ground for a certain period of time or that have been cracked or damaged should be replaced with fuses. In general, when replacing buried pipes in the ground, an open replacement method was used in which the old pipes were dug to remove the buried old pipes and the buried fuses were buried.

This open replacement method has a problem that causes traffic jams and traffic accidents due to long road occupation and control as well as increase the construction cost and time because the road must be damaged and repaved after construction. In addition, there was a problem that underground facilities such as other pipes or communication facilities that are not replaced located near the pipe to be removed when the road excavation is damaged. In addition, when a pipe to be replaced penetrates a river or a ground building, there is a problem that a water barrier construction must be preceded or a pipe must be bypassed to a part without a building.

Accordingly, an object of the present invention is to provide a buried pipe replacement method that can reduce the construction cost and construction time by minimizing the excavation area.

Another object of the present invention to provide a buried pipe replacement method that can reduce the cause of traffic jams and traffic accidents by minimizing the road occupation and control.

Another object of the present invention is to provide a buried pipe replacement method that can prevent damage to other underground facilities located near the old pipe to be removed during excavation.

Another object of the present invention is to provide a buried pipe replacement method that can be installed at the same time while removing the old pipe buried to penetrate a river or above-ground building without a separate prior process.

The buried pipe replacement method according to an embodiment of the present invention for achieving the above objects is excavated to be spaced apart by a predetermined interval so as to expose the old pipe buried in the underground in the old pipe replacement section to form a work tool, and the said of the old pipe Cutting a portion exposed by the work tool; forming a leaking portion in each of the separated old pipes, and forming a leaking portion connecting the inner space of the old pipe and the ground; and a suspension state in the ground through the leaking portion. A first friction force reduction step of reducing friction between the surface of the old pipe and soil soil in the old pipe by leaking a friction reducing agent; and repeatedly drawing the tip to the work tool by cutting the old pipe in the longitudinal direction Removing the old pipe.

The discharging step may include forming a work tool for exposing a predetermined portion of the old pipe on one side in the section to be replaced with the old pipe, cutting a portion exposed by the work tool of the old pipe, and the old pipe. It includes the process of checking the ground condition such as the use of a bend pipe or branch pipe in the underground buried part, and the process of cutting and separating the other side in the section to be replaced of the old pipe, but the separated old pipe to form a straight line, the work The sphere is formed so that the bottom surface is deeper than the bottom of the old tube.

In the above-mentioned leakage part is formed by a plurality of perforations or the upper part of the old pipe is formed by totally cutting in the longitudinal direction.

The first frictional force reducing step is performed by putting the friction reducing agent in the suspension state into the old pipe while pressing the cut portion, and using bentonite as the friction reducing agent.

The method may further include transmitting vibration to the old pipe using an air hammer or a vibration generating device in the first frictional force reducing step.

And a second friction force reduction step of applying pressure to the exposed tip of the old pipe after the first friction force reduction step to move the tip embedded in the pit of the underground to protrude into a previous work tool to further reduce the friction force. The exposed ends of the old pipes are to be pressurized with jacks operated by hydraulic or air.

The process of filling the remaining space in the underground gang by burying the fuse with a smaller diameter than the old pipe and grouting method by removing the old pipe by connecting the same or smaller fuse to the end of the old pipe. It includes more.

After removing the old pipe in the above further comprises the step of expanding the diameter of the gang in the underground to the expander and embedding a fuse having a diameter larger than the old pipe.

The buried pipe replacement method according to another embodiment of the present invention for achieving the above object is the excavation step to form a work tool by excavating a predetermined interval so that exposed old pipe buried in the ground in the old pipe replacement section, and the old pipe Cutting and separating a portion exposed by the work tool; and digging a hole in an outer upper portion of the separated old pipe and injecting a friction reducing agent to reduce friction between the surface of the old pipe and soil in the ground. And a step of removing the old pipe by repeating a plurality of steps of reducing the friction force and moving the old pipe in the longitudinal direction to draw and cut the tip to the work tool.

And a second friction force reduction step of applying a pressure to the exposed tip of the old pipe after the first friction force reduction step to move the tip embedded in the pit of the underground to protrude into a previous work tool to further reduce the friction force.

In the above, by connecting a fuse having the same diameter or smaller diameter to the end of the old pipe to remove the old pipe and at the same time buried the fuse.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic cross-sectional view showing a trench for replacing a buried old pipe according to an embodiment of the present invention, and FIG. 2 is a perspective view showing that perforations are formed in the old pipe shown in FIG. 1.

As shown in Figure 1 to replace the old pipes 13, such as water and sewage pipes, oil pipes, gas pipes and telecommunications buried in the pit of the underground 11 to replace the old pipes according to an embodiment of the present invention The first to Nth working tools 15-1, 15-2 to 15-(N-1) and 15 -N are excavated to be spaced apart by the interval L 12 in the section L 11, respectively, where N is a natural number of 2 or more. Is formed. The old pipe 13 may be made of metal pipes, such as cast iron pipes or stainless steel pipes, or synthetic resin pipes such as polyester pipes or PVC (Poly Vinyl Chloride).

In the above, the first to Nth working tools 15-1, 15-2 to 15-(N-1) and 15 -N are replaced with the old pipe 13 embedded in the pit of the ground 11. When the sections L11 are long distances of several hundred m to several km or more, the intervals L12 may be about 100 to 200 m, respectively. The old pipe 13 should be pulled out of the pit of the ground 11 to have a straight line to facilitate removal. In addition, the 1st to Nth working tools 15-1, 15-2 ... 15- (N-1), 15-N are spaced in the case where a curved pipe is used for the old pipe 13 or there is a branch pipe. Even if (L12) does not become about 100-200m, it is preferable to form in that part. Even if a river or a ground building penetrates in the section L11 to be replaced in the old pipe 13 in the above, the water net can be removed without a separate preliminary process such as construction.

In addition, the first to Nth working tools 15-1, 15-2 to 15-(N-1) and 15 -N have bottom surfaces of the old pipe 13, that is, the pit of the ground 11. Depth D11, for example, about 0.3 to 1.5 m is deeper than the lower part of i), and this bottom surface is about the length L13, for example about 3 to 10 m, in the longitudinal direction of the old pipe 13, and The width W11 (not shown) may be, for example, about 0.5 to 2.0 m perpendicular to the longitudinal direction. Further, the first to Nth working tools 15-1, 15-2 ... 15- (N-1), 15-N have a surface corresponding to the surface from which the old pipe 13 is extracted to enlarge the working space. It is preferable to incline.

In addition, the old pipe 13 of the section L11 to be replaced is cut at the first to Nth working tools 15-1, 15-2... It is buried in a gang. In the state in which the old pipe 13 to be removed is embedded in the pit of the ground 11, as shown in FIG.

In the above-mentioned perforations 17 are positioned at least in the upper, lower, left and right on the concentric circle in the old pipe 13, and a plurality of holes are formed at regular intervals in the longitudinal direction, so that the inner space and the ground of the old pipe 13 are formed. (11) to spatially connect the soil of the gang (13) when the friction reducing agent, for example bentonite suspension is injected into the interior space of the old pipe (13) is leaked to the ground (11) through the perforation (17) . The leaked bentonite suspension reduces friction between the exterior of the aging pipe 13 and the soil that forms the pit of the ground 11.

Although the hole 17 is formed in the old pipe 13 as a leaking part, the present invention also cuts the upper part of the old pipe 13 in the state where the entire length of the old pipe 13 is embedded in the gang instead of the hole 17 as the leaking part. It may be formed.

3 is a schematic cross-sectional view showing a state in which the old pipe 13 embedded in the pit of the ground 11 according to the embodiment of the present invention is replaced with a fuse 19.

Buried pipe replacement method according to an embodiment of the present invention to form the first to N-th working tool (15-1, 15-2 ... 15- (N-1), 15-N) as shown in FIG. After the trenching process is completed and the perforations 17 are formed in the old pipe 13, the frictional force between the outside of the old pipe 13 and the earth and sand of the ground 11 is reduced with bentonite suspension. The old pipe 13 embedded in the gang is removed and a fuse 19 is installed in the gang. The fuse 19 may be formed of a metal tube such as cast iron tube or stainless steel tube, or a synthetic resin tube such as polyester tube or polyvinyl chloride (PVC).

Directional indentation of the old pipe 13 embedded in the pit of the ground 11 cut by the first to Nth working tools 15-1, 15-2... 15- (N-1), 15-N. It is moved in the longitudinal direction by the device or the jack, and is drawn out to the second to Nth working tools 15-2... 15- (N-1), 15-N and cut. At this time, when the fuse 19 to be buried at the end of the old pipe 13 is connected by welding or the like, the fuse of the old pipe 13 is pulled out from the pit of the ground 11. ) Is inserted into the gang and buried.

Any of the sections between the first to Nth working tools 15-1, 15-2 ... 15- (N-1), 15-N, for example, the first and the second, by going through the above-described processes in large numbers. The old pipe 13 embedded in the pit of the ground 11 between the work tools 15-1 and 15-2 is removed, and a fuse 19 is buried in the gang at the same time. When the old pipe 13 drawn out from the pit of the ground 11 is cut in the second work tool 15-2, the new pipe 19 to be embedded in the first work tool 15-1 is welded or the like. To connect. Even if a river or ground building penetrates within the section L11 to replace the old pipe 13 embedded in the pit of the underground 11, the water net can be demolished and buried without a separate prior process such as construction.

Figure 4 is a flow chart illustrating a method for dismantling the old pipe according to an embodiment of the present invention.

Referring to step 1 (S11), a predetermined portion in the section L11 to be replaced, preferably, one end of the old pipe 13, such as water and sewage pipe, oil pipe, gas pipe, and telecommunication pipe embedded in the pit of the underground 11 The ground 11 is excavated to form a first work tool 15-1 exposing the old pipe 13. The old pipe 13 may be made of a metal pipe such as cast iron pipe or stainless steel pipe, or a synthetic resin pipe such as polyester pipe or polyvinyl chloride (PVC).

In the above-described first work tool 15-1, the old pipe 13 is exposed by an excavator or a manpower, and the lower part of the old pipe 13, that is, the depth D11 between the bottom of the gang and the bottom surface is 0.3 to 1.5. It becomes about m, and is formed so that length L13 of this bottom surface may be about 3-10m, and width W11 may be about 0.5-2.0m. It is preferable to form one side surface of the first work tool 15-1 to be inclined.

The part exposed by the 1st work tool 15-1 of the old pipe 13 is cut | disconnected and removed. Then, the end of the old tube (13) to replace the section (L11) or by examining the image taken by the camera to determine the underground conditions, such as the use of the curvature or branch and absence. In the above, the endoscope or the camera can be moved and examined while being mounted on a mobile device (not shown).

When the section L11 to be replaced of the old pipe 13 is a long distance of several hundred m to several km or more, the second to Nth working tools 15-2... (N-1) and 15-N are formed in the same manner and size as the first work tool 15-1.

The first to Nth working tools 15-1 to 15- (N-1) and 15-N are 100 to 200 m without exposing all of the old pipes 13 to be demolished embedded in the pit of the ground 11 above. By forming the gap to a minimum by minimizing the excavation area can not only reduce the construction cost and construction time, but also can reduce the post-construction recovery cost. In particular, when the old pipe 13 is buried along the road or through, it is possible to minimize the road occupancy and control to reduce the cause of traffic jams and traffic accidents. In addition, even when other underground facilities are located near the old pipe 13 to be removed, the excavation area is minimized, thereby preventing damage during excavation.

Referring to step 2 (S12), the exposed portions of the old pipe 13 are cut off by the second to Nth working tools 15-2... 15- (N-1) and 15-N. At this time, the old pipe 13 is located between the previous work tool, that is, the first to N-1 work tools 15-1, 15-2 ... 15- (N-1), the second to Nth. The tool is cut to protrude a predetermined length, for example, about 1 to 4 m, to the work tool 15-2... 15- (N-1) and 15-N. In other words, the old pipe 13 is cut so that the tip is protruded about 1 to 4 m later in the work tool.

In the above, the portion remaining in the pit of the ground 11 without being removed from the old pipe 13 should have a straight line to facilitate removal. Therefore, the space | interval L12 is provided between 2nd thru | or Nth work tools 15-2 ... 15- (N-1), 15-N, or a part with a curved pipe or a branch pipe is used. It is preferable to form in.

Referring to step 3 (S13), the soil pipe 13 remaining in the ground (11) is connected to the earth and the internal space and the ground (11) gangs spatially to form a plurality of perforations (17) used as leaks. . The perforations 17 may be formed using a perforator that can form at least four holes at equal intervals by hydraulic pressure or air pressure while moving inside the old pipe 13. Therefore, the perforations 17 can be formed on the concentric circles of the old pipe 13 at least on the upper, lower, left and right sides, respectively, and have a predetermined distance in the longitudinal direction.

In addition, the leaking part may be formed by cutting the entire upper part in the longitudinal direction in the state where the old pipe 13 is embedded in the pit of the ground 11 instead of the perforation 17.

In addition, if none of the second to N-th working tools 15-2... 15- (N-1) and 15-N is formed in the portion where the branch pipe is connected to the old pipe 13, the old pipe ( 13) and the branch pipe should be cut and separated.

Referring to step 4 (S14), the first friction force reduction step for reducing the friction force between the outside of the old pipe 13 and the soil constituting the pit of the ground (11). The first step of reducing friction is a friction reducing agent, for example bentonite, in which both ends are blocked in the old pipe 13 to be removed between the first work tool 15-1 and the second work tool 15-2. bentonite suspension is injected and pressure is applied. At this time, the bentonite suspension used as a friction reducing agent leaks into the ground 11 through a plurality of perforations 17 or cut portions, and the outside and the ground 11 of the old pipe 13 embedded in the pit of the ground 11. It flows to the interface between the soils forming the gang of), and the pressure spreads rapidly between the wider interfaces.

Bentonite suspension has a concentration of about 3% to 7% and penetrates into the ground 11 which forms an interface with the outside of the old pipe 13. As a result, the fine particles of bentonite fill the voids between the soils forming the gangs, thereby reducing the contact area between the outside of the old pipe 13 and the soils of the ground 11 to reduce friction at the interface.

In addition, when a friction reducing agent, for example, bentonite suspension, leaks through a plurality of perforations 17 or cut portions, an old hammer 13 embedded in a pit of the ground 11 is used. Vibration generators can be used to generate and transmit vibrations. As a result, the surfactant leaked through the perforations 17 or the cut portion spreads evenly around the aging pipe 13 and the frictional force between the old pipe 13 embedded in the pit of the ground 11 and the soil of the ground 11. The reduction efficiency is increased.

When the perforation 17 is not formed in the old pipe 13 in the above, the first frictional force reducing step is to excavate a small hole in the outer upper part of the old pipe 13, that is, the top of the pit of the ground 11 and reduce the friction. It may also be carried out by injecting a bentonite suspension, for example.

Then, the friction reducing agent remaining without leaking inside the old pipe 13 is removed.

Referring to step 5 (S15), in the pit of the ground 11 to be removed between the first work tool 15-1 and the second work tool 15-2 in which the first frictional force reducing step S14 has been performed. The buried old pipe 13 is moved by a predetermined distance, for example, about 1 to 4 m, to perform the second frictional force reduction in which the frictional force is reduced at the interface with the earth and sand forming the pit of the ground 11. In the above, the second frictional force is reduced by applying a pressure of about 100 to 200 tons by a jack operated by hydraulic pressure or air to the tip of the old pipe 13, that is, the protruding portion of the second work tool 15-2. It is performed by moving so that it protrudes to the working tool 15-1.

As a result, the old pipe 13 on which the first frictional force reduction step is performed is moved in the second frictional force reduction step, thereby reducing the frictional force between the soils forming the pit of the ground 11. Therefore, in the old pipe 13 embedded in the pit of the ground 11, the frictional force between the soils forming the pit of the ground 11 is reduced more than after the first frictional force reducing step is performed.

Referring to step 6 (S16), the old pipe buried in the pit of the ground 11 between the first work tool 15-1 and the second work tool 15-2 in which the first and second frictional force reducing steps have been performed. A fuse 17 having a predetermined length, for example, about 3 to 10 m in length, is connected to the end of the first work tool 15-1 by welding or the like. The fuse 19 may be formed of a metal tube such as cast iron tube or stainless steel tube, or a synthetic resin tube such as polyester tube or polyvinyl chloride (PVC).

Then, the old pipe 13 between the first work tool 15-1 and the second work tool 15-2 is a predetermined length, e.g., in the longitudinal direction, with a tensile force of 100 to 200 tons using a directional indentation device or a jack. For example, it draws out and cut | disconnects to the 2nd work tool 15-2 by about 3-10 m in length. When the old pipe 13 embedded in the pit of the ground 11 is withdrawn to the second work tool 15-2, the fuse 19 connected to the first work tool 15-1 is connected to the ground 11 of the underground 11. It is pulled into the gang and buried.

In addition, many of the above-described processes, namely, connecting the fuse 19 from the first work tool 15-1 and drawing the old pipe 13 to the second work tool 15-2, are cut in the same manner. The fuse 19 is embedded while the old pipe 13 embedded in the pit of the ground 11 is completely removed between the first work tool 15-1 and the second work tool 15-2. Even if a river or a ground building penetrates within the section L11 to replace the old pipe 13 buried in the pit of the underground 11, the new pipe 19 can be buried while being demolished without a separate preliminary process such as a water barrier construction. .

In addition, the old pipe 13 embedded between the second work tool 15-2 and the Nth work tool 15-N is also located between the first work tool 15-1 and the second work tool 15-2. The old pipe 13 can be replaced by removing and embedding it sequentially in the same manner as the new pipe 19 is replaced.

Although the present invention has been described as having an old pipe and a fuse having the same diameter, in another embodiment of the present invention, the old pipe and the fuse have different diameters, that is, even when the diameter is larger or smaller than that of the old pipe to be removed. can do.

In the case of installing a fuse having a smaller diameter than the old pipe removed from the above, one side has the same diameter as the old pipe and the other side uses a connecting pipe having the same diameter as the old pipe, while the old pipe is removed, and the grouting method is embedded. Fill in the remaining space within the gang. In addition, when installing a fuse having a larger diameter than the old pipe to be removed, it is possible to bury the fuse while removing the old pipe while expanding the diameter of the gang by expanding.

As described above, the present invention forms the first to N-th working tools for cutting and separating the old pipes in the section L11 to be replaced, spaced apart by the distance L12, respectively, and forming a perforation in each of the separated pipes, Through this drilling, a friction reducing agent such as bentonite suspension is leaked to the outside of the old pipe, and then the pressure pipe is moved under pressure to reduce the friction force between the old pipe and the soil which forms the underground gang. Then, the fuse is connected to the rear end of the old pipe to be removed, and the process of drawing and cutting the tip of the old pipe from the underground gang to the work tool is repeatedly performed. As a result, the old pipe can be removed from the underground gang and the new fuse can be embedded.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

Therefore, the present invention forms only a plurality of work zones without digging the entire replacement section, thereby minimizing the excavation area to reduce construction costs and construction time, as well as minimizing road occupation and control, resulting in traffic jams and traffic accidents. There are advantages to reducing the cause. In addition, it is possible to simultaneously remove old pipes and fuses between units, and to prevent damage to other underground facilities located nearby when removing old pipes and laying new pipes at the same time. Even if there is a ground building, there is an advantage that can be carried out without a separate prior process.

Claims (15)

An excavation step to form a work tool by digging at a predetermined interval so that the old pipe embedded in the ground in the old pipe replacement section is exposed; Cutting a portion exposed by the work tool of the old pipe; A leaking part forming step of forming a leaking part in each of the separated old pipes and connecting the internal space of the old pipe and the ground; A first frictional force reducing step of leaking a friction reducing agent in suspension state into the ground through the leaking portion to reduce frictional force between the surface of the old pipe and soil in the ground; The method of replacing the buried pipe, comprising the step of removing the old pipe by repeating the process of drawing and cutting the front end to the work tool by moving the old pipe in the longitudinal direction. The method according to claim 1, wherein the step of digging, Forming a work tool for exposing a predetermined portion of the old pipe on one side in the section to be replaced; Cutting a portion exposed by the work tool of the old pipe; Checking the underground condition such as the use of a curved pipe or the presence of branch pipes in the buried portion of the old pipe; Buried pipe replacement method comprising the step of cutting the other side in the section to be replaced of the old pipe to the separated old pipe to form a straight line. The method of claim 2, wherein the working tool is formed so that the bottom surface is deeper than the lower portion of the old pipe. The method of claim 1, wherein the leaking part is formed by a plurality of perforations or the upper part of the old pipe is formed by totally cutting in the longitudinal direction. The method of claim 1, wherein the reducing of the first frictional force is performed by putting a friction reducing agent in the suspension state into the old pipe while pressing the cut portion. The method of claim 5, wherein bentonite is used as the friction reducing agent. The method of claim 1, further comprising transmitting vibration to the old pipe by using an air hammer or a vibration generator during the first frictional force reducing step. The second frictional force reduction step of claim 1, further comprising: applying a pressure to the exposed end of the old pipe after the first frictional force reduction step to move the end embedded in the underground gang to protrude into a previous work tool, further reducing the frictional force. How to replace buried pipe. The method of claim 8, wherein the buried pipe replacement method for applying pressure to the exposed tip of the old pipe by hydraulic or air operated jack. 2. The method of claim 1, wherein a fuse having the same diameter or smaller diameter is connected to the end of the decommissioning pipe to remove the decommissioning pipe, and embed the fuse at the same time. The method of claim 10, further comprising the step of embedding a fuse having a diameter smaller than the old pipe and filling the remaining space in the underground gang by a grouting method. The method of claim 1, further comprising expanding the diameter of the gang in the underground to the air after removing the old pipe and embedding a fuse having a diameter larger than that of the old pipe. An excavation step to form a work tool by digging at a predetermined interval so that the old pipe embedded in the ground in the old pipe replacement section is exposed; Cutting and separating a portion exposed by the work tool of the old pipe; A first friction force reducing step of digging a hole in the outer upper portion of the separated old pipe and injecting a friction reducing agent to reduce the frictional force between the surface of the old pipe and the soil in the ground; The method of replacing the buried pipe, comprising the step of removing the old pipe by repeating the process of drawing and cutting the front end to the work tool by moving the old pipe in the longitudinal direction. 15. The method of claim 13, further comprising a second friction force reduction step of applying pressure to the exposed tip of the old pipe after the first friction force reduction step to move the tip embedded in the underground gang to protrude into a previous work tool to further reduce the friction force. How to replace buried pipe. The method of replacing a buried pipe according to claim 13, wherein a fuse having the same diameter or smaller diameter is connected to the end of the old pipe to remove the old pipe and at the same time bury the fuse.

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