JP2019203362A - Steel pipe for excision and tunnel excavation method using the same - Google Patents

Abstract

To provide a steel pipe for excision for a long pipe that can be easily separated and a tunnel excavation method using the same.SOLUTION: This present invention is a steel pipe for excision included in a long pipe that is inserted into a drilled hole, as the hole is drilled by a drilling bit provided on the tip side. The steel pipe includes: a cylindrical steel pipe main body; at least one annular groove formed at a predetermined interval in the axial direction on the outer peripheral surface of the steel pipe main body; at least one slit formed over the entire axial length of at least one of a region between the adjacent annular grooves and a region between the annular groove and a rear end portion in the axial direction of the steel pipe main body is formed over the entire axial length of each region; and at least one through hole formed so as to pass through a part of each annular groove or to be continuous with each annular groove, and also the slits formed in the adjacent regions are formed at positions shifted from each other in the circumferential direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steel pipe for excision included in a long pipe that enters into a drilling hole with drilling by a drilling bit provided on the tip side.

  In recent years, various construction methods for reinforcing natural ground have been proposed in tunnel construction. For example, in the long tip receiving method, a long tube is placed obliquely forward around the face and a consolidated material is injected through the long tube. Thus, the solidified material is reinforced and improved by allowing the consolidated material to penetrate into the natural ground and hardening it. In this case, the long pipe that has been laid is left in the ground, and the tunnel is excavated after reinforcing the periphery of the tunnel formation region. And the unnecessary part which protruded from the natural ground among the cast long pipes is cut | disconnected.

By the way, in Patent Document 1, a plurality of slits extending in the axial direction are formed in a region between adjacent annular grooves, in which annular grooves are formed at predetermined intervals in a steel pipe constituting a long pipe placed in a natural ground. Is disclosed. Thereby, for example, as shown in FIG. 12, when the bucket 500 of the excavator is swung down from above and the steel pipe 300 is pressed, the steel pipe 300 whose strength is reduced by the slit and the annular groove is bent and further separated. Can do. Therefore, it is disclosed that the steel pipe 300 can be easily separated and collected.
JP 2007-146498 A

  However, a high level of skill is required for the operator of the excavator in actual work, and it is difficult to fold when the blade hits or swings down. If the steel pipe 300 is not broken, the blade is swung down many times. Then, as shown in FIG. 13, every time the steel pipe 300 is pressed, an upward force is applied to the steel pipe remaining in the ground in front of the face, and the natural ground 200 may be loosened. Cause.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a cutting steel pipe for a long pipe that can be easily separated and a tunnel excavation method using the same.

  The present invention relates to a cutting steel pipe included in a long pipe that enters into a drilling hole by drilling with a drilling bit provided on the tip side, and includes a cylindrical steel pipe body and an outer periphery of the steel pipe body And at least one annular groove formed in the surface at a predetermined interval in an axial direction, a region between the adjacent annular grooves, and between the annular groove and an axial rear end of the steel pipe body. In at least one of the regions, at least one slit formed over the entire axial length of each region and a part of each annular groove or whether it is continuous with each annular groove The formed slits including at least one through hole and formed in the adjacent regions are formed at positions shifted from each other in the circumferential direction.

  According to this configuration, the following effects can be obtained when the cutting steel pipe is removed from the natural ground after the long pipe attached with the cutting steel pipe according to the present invention is placed on the natural ground. That is, annular grooves are formed in the cutting steel pipe at predetermined intervals, and slits are formed in regions partitioned by these annular grooves. Furthermore, at least one through hole is formed in each annular groove. Therefore, the slit can be easily pushed open by applying a force to the slit behind the annular groove in which the through hole is formed with an excavator or the like. That is, since each annular groove is formed with a through hole, the strength of the thin annular groove is further reduced, whereby the cutting steel pipe can be easily bent and further separated along the annular groove.

  In particular, since the strength of the annular groove is reduced, even if the excavator is pushed almost straight along the direction in which the slit extends, the slit can be expanded and the radial force acts on the steel pipe for cutting. It becomes difficult. As a result, it is possible to prevent a force that pushes the natural ground in the radial direction from the outer peripheral surface of the cutting steel pipe, thereby preventing the natural ground from loosening.

  In the cutting steel pipe, the through hole can be formed so as to be located at an equal distance from the front ends of the plurality of slits formed behind the through hole.

  According to this configuration, when the plurality of slits are spread with an excavator or the like, since the through holes in front of the slits are equidistant from the front end of each slit, the plurality of parts divided by the slits are evenly distributed. It can be bent with great force. Therefore, the force pressed with an excavator etc. can be made to act along an axial direction more. As a result, it is possible to further prevent the force that pushes the natural ground in the radial direction from the outer peripheral surface of the cutting steel pipe.

  In the steel pipe for cutting, the through hole is formed at the rear end portion of each slit, and each through hole can be formed so as to extend at least to the front end side from the annular groove.

  According to this configuration, each through hole is formed at the rear end of the slit and extends forward from the annular groove. A notch is formed at the rear end of the slit. Therefore, after separating the area behind the annular groove and further separating the area ahead of the annular groove, the excavator can be easily pushed in using this notch a.

  In the steel pipe for cutting, the through hole is formed in the annular groove, and an inner diameter of each through hole can be larger than a width of the annular groove.

  According to this configuration, the strength of the annular groove can be further reduced, and each region can be more easily bent using the annular groove as a fulcrum.

  In the first tunnel excavation method according to the present invention, at least one steel pipe having at least one opening formed on the outer peripheral surface is connected in the axial direction, and the rear end portion of the steel pipe at the end is connected to any one of the above-mentioned A step of placing a long pipe constructed by connecting steel pipes for excision around the face of a natural ground, and injecting a caking material into the long pipe, opening of each steel pipe or for excising A step of infiltrating the injection material into the natural ground through the slit of the steel pipe, and the excavation steel pipe is exposed while excavating the natural ground, and a force is applied so as to push it forward from the rear in the axial direction of the steel pipe for excision. In addition, the cutting steel pipe is bent and cut in the annular groove, and is divided by the slit, and at least a part of the cutting steel pipe together with the solidified material is removed from the ground, With That.

  The second tunnel excavation method according to the present invention includes a step of driving a long pipe formed by connecting any of the plurality of cutting steel pipes described above in the axial direction on a mirror surface of a natural face. A step of injecting a caking material into the long pipe, and infiltrating the injection material into a natural ground through the opening of each steel pipe or the slit of the steel pipe for excision, and the steel pipe for excision while excavating the natural ground The cutting steel pipe is bent and cut in the annular groove by applying a force to push the cutting steel pipe from the rear to the front in the axial direction. Removing at least a part of the steel pipe for excision from the natural ground together with the consolidated material.

  According to the steel pipe for cutting concerning the present invention, separation can be performed easily.

It is a side view showing one embodiment of a long tube concerning the present invention. It is the partial perspective view which looked at the terminal tube from the rear end side. It is a partial cross section figure of a terminal pipe. It is sectional drawing which looked at the tunnel from the side. It is sectional drawing which looked at the tunnel from the excavation direction. It is a partial cross-sectional view of a leading pipe to which a drill bit or the like is attached. It is a side view explaining the placement of the leading pipe. It is a side view explaining cutting of a terminal pipe. It is an expanded sectional view explaining cutting of a terminal pipe. It is a perspective view explaining the cutting | disconnection of the terminal tube in which the caking material was inject | poured. It is a side view which shows the other example of a terminal tube. It is a figure explaining the cutting of the conventional steel pipe for cutting. It is a figure explaining the cutting of the conventional steel pipe for cutting. It is a side view which shows the example of the elongate pipe | tube set | placed on a mirror surface. It is a side view which shows the example of the 2nd intermediate tube used for the elongate tube of FIG.

  Hereinafter, an embodiment of a long pipe including a cutting steel pipe according to the present invention as a terminal pipe will be described with reference to the drawings. As will be described later, this long pipe is applied to a tunnel long tip receiving method (so-called AGF method). In the following description, the hole forming direction is referred to as the front or front end side, and the opposite side is referred to as the rear or rear end side.

<1. Outline of long tube>
First, the long tube will be described with reference to FIG. FIG. 1 is a side view of a long tube according to this embodiment. As shown in the figure, the long pipe 100 according to the present embodiment is configured by connecting four steel pipes formed in a cylindrical shape in the axial direction. Hereinafter, these steel pipes are referred to as a leading pipe 1, a first intermediate pipe 2, a second intermediate pipe 3, and a terminal pipe (cutting steel pipe) 4 from the front end side. As will be described later, a drilling bit is attached to the tip of the leading pipe 1, and a striking force, thrust, and rotational force are applied to the drilling bit from a drilling rod inserted into the long pipe 100, and the cutting is performed. A hole is made (see FIG. 6). Then, the long tube 100 enters the hole along with the drilling by the drill bit.

  A plurality of openings 10 are formed in the axial direction and the circumferential direction in the leading pipe 1, the first intermediate pipe 2, and the second intermediate pipe 3, and these openings 10 communicate with the internal spaces of the steel pipes 1 to 3. doing. Moreover, the internal thread of the edge part of each steel pipe 1-3 is formed with the internal thread, and the edge parts of the steel pipes 1-3 are connected by the screw type coupler (illustration omitted) etc. However, the method of connecting steel pipes is not limited to this. For example, while forming a female screw at the tip of each steel pipe 1-3, forming a male screw at the rear end, these male screw and female screw A plurality of steel pipes can be connected by screwing together. Alternatively, the outer peripheral surfaces of adjacent steel pipes can be connected by a coupler.

  Next, the terminal tube 4 will be described with reference to FIGS. 2 is a partial perspective view of the terminal tube as seen from the rear end side, and FIG. 3 is a partial cross-sectional view of the terminal tube. As shown in FIG. 1, the terminal pipe 4 has three annular grooves 41 to 43 arranged at predetermined intervals in the axial direction. Here, for convenience of explanation, these three annular grooves are referred to as a first annular groove 41, a second annular groove 42, and a third annular groove 43 from the front end side. These annular grooves 41 to 43 are formed in a thin shape having a bottom portion at a predetermined depth from the outer peripheral surface of the terminal tube 4 (see FIG. 6 described later).

  The first annular groove 41 is formed in the vicinity of the tip of the terminal tube 4, and an internal thread is formed on the inner wall surface between the first annular groove 41 and the tip edge of the terminal tube 4. The second intermediate pipe 3 is connected to the second intermediate pipe 3. Hereinafter, a region between the first annular groove 41 and the tip of the terminal tube 4 is referred to as a tip region 400. Further, between the first annular groove 41 and the second annular groove 42, between the second annular groove 42 and the third annular groove 43, and between the third annular groove 43 and the rear end edge of the terminal pipe 4, It has the area | region where the length of an axial direction is substantially the same. Hereinafter, for convenience of explanation, these regions are referred to as a first region 401, a second region 402, and a third region 403. In addition, two slits are formed in each of these regions 401 to 403. Hereinafter, for convenience of explanation, the slits formed in the first region 401, the second region 402, and the third region 403 are referred to as a first slit 61, a second slit 62, and a third slit 63, respectively. And

  The slits 61 to 63 formed in each of the regions 401 to 403 are disposed on the opposite side in the radial direction across the axis of the terminal tube 4. Further, the slits 61 to 63 in the adjacent regions 401 to 403 are arranged so that the positions in the circumferential direction are shifted so that the phases are different by 90 degrees.

  Further, these slits 61 to 63 are formed so as to penetrate the terminal tube 4 and are formed over the entire axial length of each of the regions 401 to 403. For example, the first slit 61 is formed so as to connect the first annular groove 41 and the second annular groove 42, and the second slit 62 connects the second annular groove 42 and the third annular groove 43. It is formed to do. Further, the third slit 63 is formed so as to connect the third annular groove 43 and the rear end edge of the terminal pipe 4. Therefore, the third slit 63 is formed to be opened to the outside at the rear end edge of the terminal tube 4.

  Each annular groove 41 to 43 is formed with a pair of circular through holes 71 to 73 that penetrate the terminal tube 4. The through holes 71 to 73 are formed at positions facing each other across the axis of the terminal tube 4. That is, it is formed at a position shifted by 180 degrees. Here, the through holes formed in the first, second, and third annular grooves 41 to 43 are referred to as first, second, and third through holes 71 to 73, respectively. The positions where the respective through holes 71 to 73 are formed are positions shifted by 90 degrees from the rear slit. That is, when there is a slit in front of each of the through holes 71 to 73, the through hole is formed in a connecting portion between the front slit and the annular groove.

  For example, as shown in FIGS. 2 and 3, the third through hole 73 is formed at a position shifted by 90 degrees from the third slit 63, but the second slit 62 and the third annular groove 43 are connected to each other. It is formed in the part. Similarly, the second through hole 72 is formed at a position shifted by 90 degrees from the second slit 62, but is formed at a connection portion between the first slit 61 and the second annular groove 42. On the other hand, as shown in FIG. 1, since no slit is formed in front of the first through hole 71, the first through hole 71 is not connected to any slit.

  Each through-hole 71-73 has an internal diameter larger than the width | variety of each annular groove 41-43, and the width | variety of each slit 61-63, and has a connection part with each annular groove 41-43 or each slit 61-63. It is formed to include. Therefore, each through-hole 71 is extended so that a semicircular through-hole may be formed in the area | region of the front side and back side rather than it, respectively, via the annular grooves 41-43.

  Further, a semicircular cutout 74 is formed at the rear end of the third slit 63, that is, the rear end edge of the terminal tube 4. The notch 74 has an inner diameter that is larger than the width of the third slit 63.

<2. Tunnel excavation method>
First, a general tunnel long-ahead receiving method will be described. As shown in FIG. 4 and FIG. 5, in a general long tip receiving method, first, the specular spray concrete 82 is applied to the mirror surface 81 of the tunnel face 8 to temporarily press the mirror surface 81. When the mirror surface 81 is further reinforced, a known long tube 83 different from the long tube 100 described above is placed on the mirror surface 81. Similarly, the plurality of long tubes 100 described above are driven along the outer edge of the face 8. The plurality of long tubes 100 are driven in an arch shape along the outer edge of the face 8 so as to form a predetermined elevation angle θ with the tunnel axis direction X.

  When the long tube 100 is driven into a natural ground, a drill bit or the like is attached to the tip of the top tube 1. Hereinafter, this point will be described in detail with reference to FIG. FIG. 6 is a partial cross-sectional view of the leading tube to which a drill bit or the like is attached. As shown in FIG. 6, a cylindrical casing shoe 91 is attached to the tip of the leading pipe 1 by screwing or welding, and a bit adapter 92 is inserted into the casing shoe 91 by a shaft due to drilling vibration. The movement in the direction is accommodated in an allowed form. A drill bit 93 for excavating natural ground is attached to the tip of the bit adapter 92 and protrudes from the casing shoe 91. A plurality of blade bodies 931 are provided at the tip of the hole drilling bit 93, and the blade body 931 makes holes in the natural ground. A rope screw-shaped female screw is formed at the rear part of the bit adapter 92, and a drilling rod 94 is screwed into the female screw. The drilling rod 94 passes through the long tube 100 and is connected to a drilling machine 57 such as a drifter disposed behind the long tube 100 (see FIG. 7).

  More specifically, a drilling rod 94 is attached to the drilling machine 57 via a shank rod (not shown), and the tip of the drilling rod 94 is connected to the drilling bit 93 via a bit adapter 92. . A spline shaft is attached to the rear end of the shank rod, and this spline shaft is connected to the drive shaft of the drilling machine 57. That is, the drilling bit 93 is splined to the drive shaft of the drilling machine 57 through the drilling rod 94 inserted into the long tube 100 and the bit adapter 92, and rotational force, striking force, and thrust are transmitted. .

  Further, the drilling bit 93 and the bit adapter 92 are engaged with a dead end fitting key groove, and when the drilling rod 94 is driven to rotate forward together with the bit adapter 92 by the drilling machine 57, the engaged state is maintained. When reversed, the bit adapter 92 is detached from the keyway.

  Then, as shown in FIG. 7, the tip of the drill bit 93 is brought into contact with the ground surface, and the drilling machine 57 is driven to excavate the ground. However, instead of driving the long pipe 100 connecting the four steel pipes 1 to 4 to the natural ground, first, only the top pipe 1 is driven. At this time, the leading pipe 1 is driven so as to form a predetermined elevation angle θ with the tunnel axis direction X as described above. Thus, the drilling holes are formed, but since the drilling bit 93 is connected to the leading pipe 1, the leading pipe 1 also enters the ground together with the drilling bit 93. At this time, since the outer diameter of the drilling bit 93 and the outer diameter of the leading pipe 1 are substantially the same, the leading pipe 1 advances while contacting the inner wall surface of the drilling hole. Thus, when the first pipe 1 is moved into the ground, the first intermediate pipe 2 is connected to the first pipe 1 by a coupler or the like, and the second drilling rod 94 is connected in the same manner to perform drilling and placing work. Continue. Thus, as shown in FIG. 1, when the rear end of the long tube 100 having a predetermined length reaches the vicinity of the surface of the natural ground, the hole drilling machine 57 is stopped. Subsequently, the hole drilling machine 57 is reversed, the bit adapter 92 is removed from the hole drilling bit 93, and the bit adapter 92 and the hole drilling rod 94 are pulled out from the long tube 100. That is, the drill bit 93 and the long tube 100 are left in the natural ground.

  Subsequently, the consolidated material is injected into the long tube 100. At this time, as the consolidated material, various consolidated materials such as a cement-based consolidated material, a urethane-based consolidated material, and a water glass-based consolidated material can be used. First, a case where a cement-based consolidated material is used will be described. In this case, for example, the rear end portion of the long tube 100 is sealed with a mouth valve (not shown), and a plurality of injection tubes (not shown) penetrating the mouth valve are inserted into the long tube 100. . The plurality of injection tubes have different lengths, and the tip openings of the injection tubes are arranged at different positions in the axial direction of the long tube 100. Then, when the consolidation material is injected into each injection tube, the long tube 100 is filled with the consolidation material. At this time, since the distal end openings of the plurality of injection tubes are arranged at different positions in the axial direction, the inside of the long tube 100 is filled with the consolidation material at a plurality of locations. However, the water glass-based consolidated material can also be used in the same manner as the cement-based consolidated material.

  On the other hand, when using a urethane-based consolidated material, for example, a plurality of packers (not shown) are arranged inside the long tube. Each packer is arrange | positioned in the multiple places of the axial direction of the long tube 100, and closely_contact | adheres to the inner wall face of a long tube. Thereby, the internal space of the long tube is partitioned into a plurality of regions along the axial direction. Then, a plurality of injection pipes are inserted from the mouth valve, and the tip opening of each injection pipe is arranged in each partitioned region, and then the caking material is injected. Thereby, the consolidated material is uniformly filled in each region. However, the cement-based or water glass-based binder described above can also be used with the packer.

  As described above, the long tube 100 is filled with the caking material regardless of which method is used. However, when the caking material is further injected, the caking material becomes the leading tube 1, the first intermediate tube 2, and It flows out of the long tube 100 from the opening 10 formed in the second intermediate tube 3. As shown in FIG. 5, the solidified material S that has flowed out penetrates into the natural ground around the long tube 100, and the natural ground is reinforced.

  Next, as shown in FIG. 8, the unnecessary part which protrudes from the natural ground among the long tubes 100 is removed. First, as shown in FIG. 8A, a bucket 500 of an excavator such as a backhoe is engaged with a notch 74 of the terminal pipe 4, and in this state, the axial direction of the terminal pipe 4 from the rear in the axial direction to the front. The bucket 500 is pushed in by applying a force so as to push it. As a result, as shown in FIG. 8B, the third slit 63 is expanded and the third region 403 of the terminal tube 4 is separated into two parts 403 a and 403 b sandwiching the third slit 63. At this time, as shown in FIGS. 8C and 9, the two portions 403 a and 403 b swing around the thin third annular groove 43 as a fulcrum and are separated (cut off) from the third annular groove 43. ) Thereafter, the separated two parts 403a and 403b are recovered. In the example of FIG. 8, only the third region 403 is separated, but the second and first regions 402 and 401 that may be unnecessary portions can be separated in the same manner after the separation of the third region 403. it can.

  When the consolidated material is injected, as shown in FIG. 10, after the two regions 403a and 403b of the third region 403 are opened, the solidified consolidated material 600 together with the injection tube 601 described above is added. After removing from the third region 403, the two parts 403a and 403b are further pushed open to separate the 403a and 403b from the third annular groove 43. Thus, the separated consolidated material 600 and the respective regions 401 to 403 can be collected and reused as resources.

  And after removing the unnecessary part of the elongate pipe 100 which protrudes from a natural ground, as shown in FIG.5 and FIG.6, the support work 85 is built in the inner wall surface of a tunnel, and shotcrete 86 is laid. Thereafter, excavation of the tunnel is advanced while repeating the long tube 100 placement and the excavation of the mirror surface 81 and the long tube 83 that has been placed.

<3. Features>
As described above, according to the present embodiment, the following effects can be obtained. The annular grooves 41 to 43 are formed in the end tube 4 of the long tube 100 at predetermined intervals, and the slits 61 to 63 are formed in regions 401 to 403 partitioned by the annular grooves 41 to 43. Further, through holes 71 to 73 are formed at portions that intersect the annular grooves 41 to 43 at the rear ends of the slits 61 to 63. Therefore, the slits 61 to 63 can be easily pushed open by applying force to the slits 61 to 63 behind the annular grooves 41 to 43 in which the through holes 71 to 73 are formed with an excavator. That is, since the through holes 71 to 73 are formed in each of the annular grooves 41 to 43, the strength of the thin annular grooves 41 to 43 is further reduced, and thereby the end pipe 4 is extended along the annular grooves 41 to 43. Can be easily folded and further separated.

  In particular, since the strength of the annular grooves 41 to 43 is reduced, even if the excavator is pushed straight along the direction in which the slits 61 to 63 extend, the slits 61 to 63 can be pushed and widened. The radial force is less likely to act on the. As a result, it is possible to prevent a force that pushes the natural ground in the radial direction from the outer peripheral surface of the terminal pipe 4, and thus it is possible to prevent the natural ground from loosening.

  Regarding this point, in addition, in the present embodiment, since the through holes 71 to 73 are disposed at positions shifted by 90 degrees from the slits 61 to 63 behind the annular grooves 41 to 43, both the slits 61 to 63 are disposed. Through holes 71 to 73 are formed at the centers of the annular grooves 41 to 43 connecting the two. For example, as shown in FIG. 2, a third through hole 73 is formed in the third annular groove 43 at a position that is equidistant from the pair of third slits 63. Therefore, as shown in FIG. 8, when the third region 403 is expanded, the first portion 403a and the second portion 403b can be expanded with substantially the same force. Therefore, when the bucket 500 is pressed with a force so as to push it from the rear to the front, both the parts 403a and 403b can be evenly spread out. Can act. As a result, it is possible to further prevent the force that pushes the ground from the outer peripheral surface of the terminal pipe 4 in the radial direction.

  Moreover, since each through-hole 71-73 is larger than the width | variety of the slits 61-63 and is formed so that it may extend ahead rather than the annular grooves 41-43, after isolate | separating the area | region behind it, it is the last. A notch is formed at the rear end of the tail slit. For example, as shown in FIGS. 8C and 9, after the third region 403 is separated, the second region 402 including the second slit 62 is positioned at the tail end of the terminal tube 4. However, a notch 73 a which is a part of the third through hole 73 is formed at the rear end of the second slit 62. Therefore, when the second region 402 is further separated, the bucket 500 of the excavator can be easily pushed in using the notch 73a.

<4. Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Note that the following modifications can be combined as appropriate.

<4-1>
The position and number of through holes are not particularly limited. In the above embodiment, the through hole is arranged at a position shifted by 90 degrees from the slit behind the annular groove. However, any position may be used to weaken the strength of the annular groove. However, in order to obtain the above-described effect, it is preferable to provide at the position of the above embodiment. Further, in order to use the through hole as a notch, it is preferable to form the through hole so as to be connected to the front slit.

  Further, the shape of the through hole is not particularly limited, and can be various shapes as shown in FIG. For example, a rectangular through hole 73 is formed in FIG. In FIG. 11B, a semicircular through hole is formed and arranged in a region on the front side of the annular groove. At this time, the through-hole may be included in a part of the annular groove, or the through-hole may be formed in the annular groove so as to be continuous with the annular groove. As a similar form, it may be formed in a triangular shape in front of the annular groove as shown in FIGS. The difference between FIG. 11C and FIG. 11B is the axial length of the annular groove.

<4-2>
The number and position of the slits are not particularly limited, and three or more slits may be provided in each region. Similarly, the number and position of the annular grooves are not particularly limited.

<4-3>
In the said embodiment, although the long pipe is comprised by connecting four steel pipes, the number of the steel pipes which comprise the long pipe 100 is not specifically limited. For example, by increasing or decreasing the number of intermediate tubes, the total length of the long tube 100 can be increased or decreased.

<4-4>
In the said embodiment, although the elongate pipe which concerns on this invention is applied to the elongate tip receiving construction method, it can also be applied to the elongate pipe placed on the mirror surface 81. Since all the long tubes placed on the mirror surface 81 are removed, not only the terminal tube 4 but also all other steel tubes 1 to 3 have the same configuration as the terminal tube 4, that is, an annular groove, a slit, and a through hole. It is necessary to form holes. This point will be described with reference to FIGS. 14 and 15.

  In the long pipe shown in FIG. 14, the annular grooves 41 to 44, the slits 61 to 63, and the through holes 71 to 73 and 75 are formed in all the steel pipes 1 to 4 in the same manner as the terminal pipe 4. However, unlike the terminal pipe 4, the leading pipe 1, the first and second intermediate pipes 2 and 3 are formed as shown in FIG. Since the configurations of the leading pipe 1, the first and second intermediate pipes 2 and 3 are substantially the same, the second intermediate pipe 3 will be described as an example here.

  As shown in FIG. 15, the second intermediate pipe 3 has the same configuration as that of the terminal pipe 4, and includes first to third annular grooves 41 to 43, first to third slits 61 to 63, and first to third. Although it has the through-holes 71-73, it has the 4th annular groove 44 connected with the rear end of the 3rd slit 63 in addition to this. The fourth annular groove 44 has substantially the same shape as the first to third annular grooves 41 to 43, but is separated from the rear end of the second intermediate pipe 3 by a predetermined length. A rear end region 304 is provided between the second intermediate pipe 3 and the rear end. A female screw is formed on the inner wall surface of the rear end region 304, and a coupler for connecting to the terminal tube 4 is screwed into the female screw. In addition, a fourth through hole 75 having substantially the same shape as the first to third through holes 71 to 73 is formed at a connecting portion between the rear end of the third slit 63 and the fourth annular groove 44. Thus, the leading pipe 1, the first and second intermediate pipes 2 and 3 are different from the terminal pipe 4 mainly in that they have a connecting portion at the rear end.

  When a long tube as shown in FIG. 14 is placed on the mirror surface, the first to third regions 401 to 403 of the terminal tube 4 are separated as shown in the above embodiment. Thereafter, in order to excavate the mirror surface, it is also necessary to separate the leading region 400 of the terminal pipe 4 and the rear end region 304 of the second intermediate pipe 3 which are connected portions. However, since these regions 400 and 304 are formed with female threads, even if no slit is formed, if an impact is applied with a bucket when the region 400 or 300 is exposed to the tunnel space, the second intermediate tube Since the third fourth annular groove 44 is cut together with the consolidated material consolidated in the pipe, it can be easily separated.

  When the leading region 400 of the terminal pipe 4 and the rear end region 304 of the second intermediate tube 3 are separated, the fourth annular groove 44 of the second intermediate tube 2 becomes the rear end. At this time, since the semicircular cutout is formed at the rear end of the third slit 63 by the fourth through hole 75, thereafter, as shown in the above embodiment, each region of the steel pipe may be separated. .

  The top tube 1 and the first and second intermediate tubes 2 and 3 described here are examples, and the numbers and positions of the annular grooves, slits, and through holes can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1 Top pipe 2 1st intermediate pipe 3 2nd intermediate pipe 4 Terminal pipe 41-43 Annular groove 61-63 Slit 71-73 Through-hole 74 Notch

Claims (6)

A steel pipe for excision included in a long pipe entering into the drilling hole, with the drilling by the drilling bit provided on the tip side,
A cylindrical steel pipe body;
On the outer peripheral surface of the steel pipe main body, at least one annular groove formed at a predetermined interval in the axial direction;
A plurality of regions formed over the entire axial length of each region in at least one of the region between adjacent annular grooves and the region between the annular groove and the axial rear end of the steel pipe body. And slits
At least one through-hole formed so as to pass through a part of each annular groove or to be continuous with each annular groove;
With
The slitting steel pipe formed in the position which mutually shifted in the circumferential direction the slit formed in the said adjacent area | region.   The steel pipe for excision according to claim 1, wherein the through hole is formed so as to be located at an equal distance from a front end of the plurality of slits formed behind the through hole. The through hole is formed at the rear end of each slit,
3. The cutting steel pipe according to claim 1, wherein each of the through holes is formed so as to extend at least toward the tip side of the annular groove. The through hole is formed in the annular groove,
The steel pipe for excision according to any one of claims 1 to 3, wherein an inner diameter of each through hole is larger than a width of the annular groove. 5. At least one steel pipe having at least one opening formed on the outer peripheral surface is connected in the axial direction, and the cutting steel pipe according to any one of claims 1 to 4 is connected to a rear end portion of the rearmost steel pipe. A step of placing a long tube composed of
Injecting a consolidated material into the long pipe, and infiltrating the injected material into a natural ground through the opening of each steel pipe or the slit of the cutting steel pipe;
The excavation steel pipe is exposed while excavating a natural ground, and the excision steel pipe is bent and cut in the annular groove by applying a force to push the excavation steel pipe from the rear to the front in the axial direction. And dividing by the slit, and removing at least a part of the cutting steel pipe together with the solidified material from the ground,
Tunnel excavation method equipped with. A step of driving a long pipe constituted by connecting a plurality of cutting steel pipes according to any one of claims 1 to 4 in an axial direction on a mirror surface of a face of a natural ground;
Injecting a consolidated material into the long pipe, and infiltrating the injected material into a natural ground through the opening of each steel pipe or the slit of the cutting steel pipe;
The excavation steel pipe is exposed while excavating a natural ground, and the excision steel pipe is bent and cut in the annular groove by applying a force to push the excavation steel pipe from the rear to the front in the axial direction. And dividing by the slit, and removing at least a part of the cutting steel pipe together with the solidified material from the ground,
Tunnel excavation method equipped with.