JP2009041758A - Boring method to bore hole in main pipe embedded in ground and guide device used for the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To turn the rotation center of a core cutter for boring a hole in a main pipe embedded in the ground toward the axis line of the main pipe. <P>SOLUTION: This boring method to bore a hole in the main pipe embedded in the ground includes: preparing a guide device including a guide member having a through hole in the center and an arcuate cross section; drilling a branch pipe hole in the ground; arranging a sheath pipe inside the branch pipe hole; inserting the guide device to the sheath pipe until the inner face of the guide member comes into close contact with the outer face of the main pipe; confirming the close contact state of inner face of the guide member with the outer face of the main pipe; inserting the core cutter to bore the hole in the main pipe to the sheath pipe until the core cutter reaches the outer face of the main pipe via the through hole; and boring the hole in the main pipe by the core cutter. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a drilling method for drilling a hole in the main pipe in order to connect a branch pipe to the main pipe embedded in the ground, and a guide device used therefor.

In order to connect a branch pipe to a main pipe, such as a water supply or a sewer, buried in the ground, a hole is made in the main pipe. Conventionally, when the hole is drilled in the main pipe, first, a branch pipe hole is excavated in the ground from the surface to the main pipe, and then in the branch pipe hole, the sheath is coaxial with the branch pipe hole. A pipe is placed, and then a core cutter for making the hole in the main pipe is inserted into the sheath pipe until the core cutter reaches the outer surface of the main pipe, and the hole is made in the main pipe by the core cutter ( Patent Document 1).
Japanese Patent Laid-Open No. 1-275983

  By the way, because there is an error between the actual position of the main pipe and the design position, or because of a construction error when excavating the branch pipe hole, the pipe is disposed in the branch pipe hole. In addition, the axis of the sheath tube may not face the axis of the main tube. For this reason, when the hole is formed in the main pipe, the center of rotation of the core cutter cannot be directed to the axis of the main pipe. When the center of rotation of the core cutter is oriented toward the axis of the main pipe, the shape of the hole is circular, whereas when the center of rotation of the core cutter is not oriented toward the axis of the main pipe, The shape becomes non-circular. When the shape of the hole is non-circular, it is difficult to process the end portion of the branch pipe fixed to the hole into a shape that matches the shape of the hole, compared to the case where the shape of the hole is circular. Become. For this reason, the processing of the end of the branch pipe requires a lot of labor and time, and the branch pipe cannot be efficiently connected to the main pipe. Further, since the end portion of the branch pipe cannot be processed with high accuracy, there is a problem that a gap is formed between the branch pipe and the main pipe, and groundwater flows into the main pipe through the gap.

  An object of the present invention is to enable the center of rotation of a core cutter for making a hole in a main pipe embedded in the ground to be directed to the axis of the main pipe.

  In the present invention, the inner surface of the guide member having a through hole in the central portion and having an arc-shaped cross section is brought into close contact with the outer surface of the main pipe, and after confirming the close contact, the hole is formed in the main pipe. By making the core cutter reach the main pipe through the through hole, the center of rotation of the core cutter can be directed to the axis of the main pipe.

  The drilling method according to the present invention is a drilling method for drilling a hole in the main pipe in order to connect a branch pipe to the main pipe having a circular cross-sectional shape embedded in the ground. The drilling method includes a first step of providing a guide device including a guide member having a through hole in a central portion and having an arc-shaped cross-sectional shape in which a curvature of an inner surface is substantially equal to a curvature of an outer surface of the main pipe; A second step of excavating a branch pipe hole from the ground surface toward the main pipe on the ground; a third step of arranging a sheath pipe coaxially with the branch pipe hole in the branch pipe hole; A fourth step of inserting into the sheath tube until the inner surface of the guide member is in close contact with the outer surface of the main tube, a fifth step of confirming the close contact of the inner surface of the guide member with the outer surface of the main tube, and the guide member When the close contact of the inner surface of the main pipe with the outer surface of the main pipe is confirmed, a core cutter for drilling the hole in the main pipe is inserted into the sheath pipe until the core cutter reaches the outer surface of the main pipe through the through hole. 6th step, and the core cutter Ri and a seventh step of drilling the hole in the main pipe.

  The inner surface of the guide member having the through hole in the central portion and having an arcuate cross-sectional shape is brought into close contact with the outer surface of the main pipe. The hole axis is directed to the main axis. For this reason, after confirming the close contact of the inner surface of the guide member with the outer surface of the main pipe, the core cutter is caused to reach the outer surface of the main pipe through the through hole, so that the center of rotation of the core cutter is adjusted to the main pipe. Can be directed to the axis.

  The guide device has one end portion and the other end portion so that when the inner surface of the guide member is in close contact with the outer surface of the main pipe, the guide member has a linear shape intersecting the axis line when viewed in a plane parallel to the main axis line. Each of the guide members has a display body that is fixed to one and the other of the two opposing areas, and exhibits a non-linear shape when not in close contact, and the fifth step confirms that the display body is linear To do. By confirming that the display body is linear, it is possible to easily confirm the close contact of the inner surface of the guide member with the outer surface of the main pipe.

  Prior to the fifth step, a CCD camera for photographing the display body and a monitor connected to the CCD camera for displaying an image of the display body are prepared, and the CCD camera is connected to the sheath. The fifth step includes photographing the display body with the CCD camera and displaying an image of the display body on the monitor.

  The guide device includes a cylindrical member attached to the guide member in alignment with the through hole, and the sixth step includes the core cutter through which the core cutter passes through the cylindrical member and the through hole. Inserting into the sheath tube until it reaches the outer surface of the tube. The cylindrical member guides the core cutter to the through hole. For this reason, the core cutter can be easily inserted into the sheath tube.

  When the inner surface of the guide member is not confirmed to be in close contact with the outer surface of the main pipe in the fifth step, the inner surface of the guide member is separated from the outer surface of the main pipe prior to the sixth step; Check that the inner surface of the guide member is in close contact with the outer surface of the main tube, and that the inner surface of the guide member is in close contact with the outer surface of the main tube, that the inner surface of the guide member is in close contact with the outer surface of the main tube. Including repeating until.

  The guide device according to the present invention is used in a drilling method for drilling a hole in the main pipe in order to connect a branch pipe to the main pipe having a circular cross-sectional shape embedded in the ground. The guide device includes a guide member having a through-hole in a central portion and an arc-shaped cross-sectional shape in which the curvature of the inner surface is substantially equal to the curvature of the outer surface of the main tube, and the outer surface of the main tube on the inner surface of the guide member One end and the other end are fixed to one and the other of the two opposing areas of the guide member, respectively, so as to present a straight line intersecting the axis when viewed in a plane parallel to the main axis. And a display body that exhibits a non-linear shape when not in close contact.

  The guide device includes a cylindrical member attached to the guide member in alignment with the through hole.

  The said display body is linear or strip | belt shape. The display body can be made of a non-stretchable material, and can be made of a stretchable material. The non-stretchable material is a synthetic resin or cloth. The stretchable material is rubber.

  According to the present invention, the inner surface of the guide member having a through hole in the central portion and having an arcuate cross-sectional shape is brought into close contact with the outer surface of the main tube. Sometimes the axis of the through hole is directed to the axis of the main. For this reason, after confirming the close contact of the inner surface of the guide member to the outer surface of the main pipe, the core cutter for drilling a hole in the main pipe is made to reach the outer surface of the main pipe through the through hole. The center of rotation of the core cutter can be directed to the axis of the main pipe.

  As shown in FIG. 1, a main pipe 10 such as a water supply or a sewer is buried in the ground 12. The main pipe 10 is made of concrete, plastic or the like and has a circular cross-sectional shape. In order to connect a branch pipe (not shown) made of plastic such as vinyl chloride to the main pipe 10, a hole 14 is formed in the main pipe 10 (FIG. 13).

  As shown in FIGS. 3 and 4, a guide device 16 is used to make a hole 14 in the main pipe 10. The guide device 16 includes a guide member 18 having an arcuate cross-sectional shape, a linear shape in which one end portion 20 and the other end portion 22 are fixed to one and the other of the two regions 24 and 26 facing each other. A band-shaped display 28.

  The guide member 18 is made of metal, plastic, etc., and the curvature of the inner surface 30 is substantially equal to the curvature of the outer surface 32 of the main pipe 10 and has a through hole 34 in the center. The through hole 34 has a circular planar shape. Since the curvature of the inner surface 30 of the guide member 18 is substantially equal to the curvature of the outer surface 32 of the main pipe 10, the inner surface 30 of the guide member 18 can be in close contact with the outer surface 32 of the main pipe 10. Since the guide member 18 has a through-hole 34 in the center, the center of the through-hole 34 is the center when viewed from a plane parallel to the axis of the main pipe 10 when the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main pipe 10. Located on the axis of the tube 10. For this reason, the core cutter 60 for piercing the hole 14 in the main pipe 10 (FIG. 11) reaches the outer surface 32 of the main pipe 10 through the through hole 34, thereby guiding the core cutter 60 on the axis of the main pipe 10. The center of the hole 14 does not deviate from the axis of the main pipe 10.

  In the illustrated example, the guide member 18 has an octagonal planar shape, and the region of the guide member 18 is two opposing portions 24 and 26 of the guide member 18. The planar shape of the guide member 18 may be a circle, a square, a rectangle, or the like instead of the illustrated example of an octagon. When the planar shape of the guide member 18 is circular, the region of the guide member 18 is two opposing portions at the peripheral edge of the guide member 18. When the planar shape of the guide member 18 is a square, the region of the guide member 18 is two opposite side portions of the guide member 18. When the planar shape of the guide member 18 is a rectangle elongated in a direction perpendicular to the axis of the main pipe 10, the regions of the guide member 18 are two opposite ends of the guide member 18.

  The one end 20 and the other end 22 of the display body 28 are parallel to the axis of the main tube 10 when the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main tube 10 as shown in FIG. The guide member 18 is fixed to one region 24 and the other region 26 so as to form a straight line intersecting the axis when viewed in a plane. In the example shown in the figure, the fixing is such that the display body 28 has a linear shape perpendicular to the axis of the main pipe 10, but instead the display body 28 is inclined with respect to the axis of the main pipe 10. You may be made to show a linear form.

  As shown in FIG. 17, in the display body 28, one end 20 and the other end 22 are arranged in close contact with one region 24 and the other region 26 of the guide member 18, respectively, and the end portions 20 and 22 are fixed. It is fixed by means 36. The fixing means 36 includes a plate member 38 disposed in close contact with the display body 28 on the side opposite to the guide member 18, and two screws 40 that respectively penetrate the plate member and are screwed with the guide member 18. Become.

  In order for the display body 28 to exhibit a straight line intersecting the axis of the main pipe 10 when the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main pipe 10, the length of the display body 28 is It is almost equal to the length along the circumferential direction, and is set by the equation L = (π × D × θ) / 360 + 2X. Here, L is the length of the display body 28, D is the outer diameter of the main pipe 10, and θ is the central angle of the arc defined by the inner surface 30 of the guide member 18 in the cross section of the guide member 18 ( 18), X denotes one end 20 and the other end of the display body 28 in order to fix the one end 20 and the other end 22 of the display body 28 to one region 24 or the other region 26 of the guide member 18, respectively. This is the length required for each of 22.

  The display body 28 has a non-linear shape when the inner surface 30 of the guide member 18 is not in close contact with the outer surface 32 of the main pipe 10. Since the display body 28 exhibits a straight line shape that intersects the axis of the main pipe 10 when the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main pipe 10, and exhibits a non-linear shape when not in close contact, the inner surface of the guide member 18. It is confirmed that the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main pipe 10 by confirming that the display body 28 is linear when the 30 is in close contact with the outer surface 32 of the main pipe 10. can do.

  The display body 28 can be made of a non-stretchable material such as synthetic resin or cloth, and can be made of a packing band made of synthetic resin, for example. Further, the display body 28 can be made of a stretchable material such as rubber. When the display body 28 is made of a stretchable material, the length of the display body 28 satisfies the above-mentioned formula because the display body 28 slightly extends when the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main pipe 10. The length may be shorter than the length obtained by the above-described formula to the extent that it becomes the length.

  As illustrated in FIG. 17, the guide device 16 includes a cylindrical member 42 that is aligned with the through hole 34 and attached to the guide member 18. The cylindrical member 42 is made of metal, plastic, or the like. The cylindrical member 42 has an inner diameter substantially equal to the outer diameter of the core cutter 60, and guides the core cutter 60 to the through hole 34 of the guide member 18 (FIGS. 11 and 12). The cylindrical member 42 has two flanges 44 at the lower end portion spaced in the radial direction of the cylindrical member. Each flange 44 is in contact with the guide member 18, and is fixed to the guide member 18 by a bolt that penetrates the flange 44 and the guide member 18 and a nut (not shown) screwed into the bolt.

  The guide device 16 is further disposed between the introduction walls 46 and a plurality of introduction walls 46 that are symmetrically attached to the upper end portion of the cylindrical member 42 with respect to the axis of the cylindrical member. And two rod-shaped members 48 attached at intervals in the radial direction of the cylindrical member. Each introduction wall 46 has a wall surface 50 inclined with respect to the inner surface of the cylindrical member 42, and the wall surface 50 of one introduction wall 46 and the wall surfaces of the other introduction walls 46 when viewed in a cross section including the axis of the cylindrical member 42. The space between the first member 50 and the second member 50 gradually increases upward from the cylindrical member 42. The introduction wall 46 introduces the core cutter 60 into the cylindrical member 42. Each rod-shaped member 48 extends upward from the tubular member 42. The rod-shaped member 48 is used to insert the guide device 16 into the sheath tube 56.

  When the hole 14 is bored in the main pipe 10, first, the guide device 16 is prepared. Next, as shown in FIG. 1, a branch pipe hole 54 is excavated in the ground 12 from the ground surface 52 toward the main pipe 10. The excavation of the branch pipe hole 54 is performed using an excavator having a rotary bit such as an auger. In the illustrated example, the branch pipe hole 54 is perpendicular to the ground surface 52, but may instead be inclined to the ground surface 52.

  Next, a sheath pipe 56 is disposed coaxially with the branch pipe hole in the branch pipe hole 54 (FIGS. 1 and 2). The sheath tube 56 is made of metal, for example. The arrangement of the sheath pipe 56 may be by inserting the sheath pipe 56 into the branch pipe hole 54 after excavating the branch pipe hole 54, or inserting the sheath pipe 56 into the branch pipe hole 54 while excavating the branch pipe hole 54. It may be by doing.

  Thereafter, as shown in FIGS. 3 to 6, the guide device 16 is inserted into the sheath tube 56 until the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main tube 10. Since the guide member 18 has a through hole 34 at the center, when the inner surface 30 of the guide member 18 is brought into close contact with the outer surface 32 of the main pipe 10, the center of the through hole 34 is viewed in a plane parallel to the axis of the main pipe 10. Is located on the axis of the main pipe 10. That is, the axis of the through hole 34 faces the axis of the main pipe 10.

  When the guide device 16 is inserted into the sheath pipe 56, the guide member 18 is pressed against the main pipe 10 using the rod-like member 48 in order to bring the inner surface 30 of the guide member 18 into close contact with the outer surface 32 of the main pipe 10. When the center of the through hole 34 of the guide member 18 is slightly shifted from the axis of the main pipe 10, that is, when there is a gap between the inner surface 30 of the guide member 18 and the outer surface 32 of the main pipe 10, the guide member 18 is By pressing against the main pipe 10, the inner surface 30 of the guide member 18 can be forcibly brought into close contact with the outer surface 32 of the main pipe 10. Thereby, the guide device 16 can be guided to a position where the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main pipe 10.

  As shown in FIGS. 3 and 4, until the inner surface 30 of the guide member 18 comes into close contact with the outer surface 32 of the main pipe 10, the display body 28 is slack and has a non-linear shape. As shown in FIG. 6, when the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main tube 10, the display body 28 is in close contact with the outer surface 32 of the main tube 10 and is a plane parallel to the axis of the main tube 10. As shown in FIG. 2, it forms a straight line intersecting the axis.

  Thereafter, it is confirmed that the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main pipe 10 by confirming that the display body 28 is linear. When the display body 28 is linear, the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main pipe 10, and when the display body 28 is not linear, the inner surface 30 of the guide member 18 is main pipe. 10 is not in close contact with the outer surface 32. In order to confirm the close contact of the inner surface 30 of the guide member 18 to the outer surface 32 of the main pipe 10 by checking whether or not the display body 28 is linear, the close contact of the inner surface 30 of the guide member 18 to the outer surface 32 of the main pipe 10 is determined. Confirmation is easy. Confirmation that the display body 28 is linear may be made by visual observation or using a CCD camera 58 as shown in FIGS.

  When the CCD camera 58 is used to confirm the close contact between the inner surface 30 of the guide member 18 and the outer surface 32 of the main pipe 10, the CCD camera 58 for photographing the display body 28 and the CCD camera are connected in advance. A monitor (not shown) for displaying an image of the display body 28 is prepared. Next, as shown in FIGS. 7 and 8, the CCD camera 58 is inserted into the sheath tube 56. Thereafter, the display body 28 is photographed by the CCD camera 58, and an image of the display body is displayed on the monitor, thereby confirming that the display body 28 is linear.

  When the close contact between the inner surface 30 of the guide member 18 and the outer surface 32 of the main pipe 10 is confirmed, as shown in FIGS. 9 to 14, the core cutter 60 has a cylindrical member 42 for the core cutter 60 for making the hole 14 in the main pipe 10. Then, the tube is inserted into the sheath tube 56 until it reaches the outer surface 32 of the main pipe 10 through the through hole 34, and the hole 14 is made in the main pipe 10 by the core cutter 60. At this time, the core cutter 60 is introduced into the cylindrical member 42 by the introduction wall 46 and is guided to the through hole 34 by the cylindrical member.

  As shown in FIGS. 15 and 16, when the display body 28 is not linear, the inner surface 30 of the guide member 18 is not in close contact with the outer surface 32 of the main pipe 10. In this case, that is, when the close contact between the inner surface 30 of the guide member 18 and the outer surface 32 of the main pipe 10 is not confirmed, the inner surface 30 of the guide member 18 is separated from the outer surface 32 of the main pipe 10 and the inner surface 30 of the guide member 18 is moved. The outer surface 32 of the main pipe 10 is brought into close contact with the inner surface 30 of the guide member 18 again to confirm the close contact with the outer surface 32 of the main pipe 10. The inner surface 30 of the guide member 18 is separated from the outer surface 32 of the main tube 10, the inner surface 30 of the guide member 18 is closely attached to the outer surface 32 of the main tube 10, and the inner surface 30 of the guide member 18 is contacted with the outer surface 32 of the main tube 10. The confirmation of the adhesion is repeated until the adhesion of the inner surface 30 of the guide member 18 to the outer surface 32 of the main pipe 10 is confirmed. After confirming that the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main pipe 10, the core cutter 60 reaches the outer surface 32 of the main pipe 10 through the cylindrical member 42 and the through hole 34 as described above. Until then, the tube is inserted into the sheath tube 56, and the hole 14 is made in the main tube 10 by the core cutter 60.

  When the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main pipe 10, the axis of the through hole 34 faces the axis of the main pipe 10, so that the inner surface 30 of the guide member 18 is in close contact with the outer surface 32 of the main pipe 10. After confirming the above, the core cutter 60 reaches the outer surface 32 of the main pipe 10 through the through-hole 34, so that the center of rotation of the core cutter 60 can be directed to the axis of the main pipe. A hole 14 can be drilled towards.

Sectional drawing of the main pipe | tube after arrange | positioning a sheath pipe in the hole for branch pipes. The perspective view of the main pipe | tube after arrange | positioning a sheath pipe in the hole for branch pipes. Sectional drawing of a main pipe | tube when inserting the guide apparatus in a sheath pipe. The perspective view of the main pipe | tube when inserting the guide apparatus in a sheath pipe. Sectional drawing of the main pipe | tube after inserting a guide apparatus in a sheath pipe. The perspective view of the main pipe | tube after inserting a guide apparatus in a sheath pipe. Sectional drawing of the main pipe | tube when confirming contact | adherence to the outer surface of the main pipe | tube of the inner surface of a guide member. The perspective view of the main when the close_contact | adherence to the outer surface of the main pipe | tube of the inner surface of a guide member is confirmed. Sectional drawing of the main pipe | tube when the core cutter is inserted in the sheath pipe. The perspective view of the main pipe | tube when inserting the core cutter into a sheath pipe. Sectional drawing of a main pipe | tube when making a hole in a main pipe | tube with a core cutter. The perspective view of a main when a hole is made in a main with a core cutter. Sectional drawing of a main pipe after making a hole in the main pipe. The perspective view of the main pipe after making a hole in the main pipe. Sectional drawing of the main pipe | tube of the state in which the inner surface of a guide member is not closely_contact | adhered to the outer surface of the main pipe. The perspective view of the main body in the state where the inner surface of the guide member is not in close contact with the outer surface of the main body. Explanatory drawing regarding the attachment method to the guide member of a display body. Explanatory drawing regarding the setting method of the length of a display body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Main pipe 12 Ground 14 Hole 16 Guide apparatus 18 Guide member 20 One end part 22 Other end part 24, 26 Area 28 Display body 30 Inner surface 32 Outer surface 34 Through-hole 42 Cylindrical member 54 Branch pipe hole 56 Sheath pipe 58 CCD camera 60 Core cutter

Claims (12)

A drilling method for drilling a hole in the main pipe to connect a branch pipe to a main pipe having a circular cross-sectional shape embedded in the ground,
A first step of providing a guide device including a guide member having a through hole in the central portion and having an arc-shaped cross-sectional shape in which the curvature of the inner surface is substantially equal to the curvature of the outer surface of the main pipe;
A second step of excavating a branch pipe hole from the ground surface to the main pipe in the ground;
A third step of arranging a sheath pipe coaxially with the branch pipe hole in the branch pipe hole;
A fourth step of inserting the guide device into the sheath tube until the inner surface of the guide member is in close contact with the outer surface of the main pipe;
A fifth step of confirming adhesion of the inner surface of the guide member to the outer surface of the main pipe;
When the tightness of the inner surface of the guide member to the outer surface of the main pipe is confirmed, the core cutter for punching the hole in the main pipe is inserted into the sheath until the core cutter reaches the outer surface of the main pipe through the through hole. A sixth step of inserting into the tube;
And a seventh step of drilling the hole in the main pipe with the core cutter.   The guide device has one end portion and the other end portion so that when the inner surface of the guide member is in close contact with the outer surface of the main pipe, the guide member has a linear shape intersecting the axis line when viewed in a plane parallel to the main axis line. Each of the guide members has a display body that is fixed to one and the other of the two opposing areas, and exhibits a non-linear shape when not in close contact, and the fifth step confirms that the display body is linear The perforation method according to claim 1.   Prior to the fifth step, a CCD camera for photographing the display body and a monitor connected to the CCD camera for displaying an image of the display body are prepared, and the CCD camera is connected to the sheath. 3. The drilling method according to claim 2, comprising inserting into a tube, wherein the fifth step includes photographing the display body with the CCD camera and displaying an image of the display body on the monitor.   The guide device includes a cylindrical member attached to the guide member in alignment with the through hole, and the sixth step includes the core cutter through which the core cutter passes through the cylindrical member and the through hole. The drilling method according to claim 1, comprising inserting into the sheath tube until reaching the outer surface of the tube.   When the inner surface of the guide member is not confirmed to be in close contact with the outer surface of the main pipe in the fifth step, the inner surface of the guide member is separated from the outer surface of the main pipe prior to the sixth step; Check that the inner surface of the guide member is in close contact with the outer surface of the main tube, and that the inner surface of the guide member is in close contact with the outer surface of the main tube, that the inner surface of the guide member is in close contact with the outer surface of the main tube. The drilling method according to claim 1, comprising repeating the process until it is performed.   A guide device used in a drilling method for drilling a hole in the main pipe in order to connect a branch pipe to a main pipe having a circular cross-sectional shape embedded in the ground, and having a through hole in the center portion, A guide member having an arc-shaped cross-sectional shape in which the curvature of the inner surface is substantially equal to the curvature of the outer surface of the main pipe, and a plane parallel to the axis of the main pipe when the inner surface of the guide member is in close contact with the outer surface of the main pipe One end and the other end are fixed to one and the other of the two opposing areas of the guide member so as to exhibit a straight line crossing the axis as viewed, and a display body that exhibits a non-linear shape when not in close contact Including a guide device.   The guide device according to claim 6, comprising a cylindrical member attached to the guide member in alignment with the through hole.   The guide device according to claim 6, wherein the display body is linear or strip-shaped.   The guide device according to claim 6, wherein the display body is made of a non-stretchable material.   The guide device according to claim 9, wherein the non-stretchable material is a synthetic resin or a cloth.   The guide device according to claim 6, wherein the display body is made of a stretchable material.   The guide device according to claim 11, wherein the stretchable material is rubber.

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