JP2018193796A - Starting mechanism in shield method and pipeline construction method in shield method - Google Patents

Abstract

To eliminate a bearing wall in a shield method using both starting shafts.SOLUTION: A starting mechanism has: a first well head ring HR1 provided integrally with well-forming concrete forming a first well head H1; a second well head ring HR2 provided integrally with well-forming concrete forming a second well head H2; a seal ring SR selectively coupled with the first well head ring HR1 and the second well head ring HR2; and a reaction force member 4 connected to the well head rings HR1, HR2, with which the seal ring SR is not coupled, via a connecting piece 6 and for receiving a reaction force when a shield machine 2 is propelled. A first pipe line is constructed by coupling the seal ring SR with the first well head ring HR1 and connecting the reaction force member 4 to the second well head ring HR2, and a second pipe line is constructed by coupling the seal ring SR with the second well head ring HR2 and connecting the reaction force member 4 to the first well head ring HR1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a start mechanism in a shield method and a pipe construction method in the shield method, and more particularly to a technique effective when applied to the start of a shield machine in the shield method of both start shafts.

  The shield construction method has a start shaft and a reach shaft at both ends of the planned pipeline line, while excavating the front ground with a shield machine from the entrance of the start shaft, sequentially adding segments to the rear end of the shield machine, This is a method of constructing a pipe line by pushing the rear end of the segment row with a propulsion jack installed in the starting shaft, thereby causing the shield machine to reach the reaching shaft.

  Here, in the shield construction method, two wellheads, the first wellhead and the second wellhead, are formed in the start shaft (both start shafts), and the two pipes are excavated from each well using a shield machine. May build.

  And when constructing a pipe line by starting a shield machine from the first wellhead at both start pits, a concrete bearing wall is installed using the second wellhead. Received the reaction force of shield machine. Next, when constructing a pipeline from the second wellhead, the bearing wall of the first wellhead installed is removed, and this time the concrete bearing wall is made using the first wellhead. It is installed. And if the pipe line from the 2nd wellhead is constructed, the bearing wall of the 2nd wellhead will be removed.

  For example, Patent Document 1 discloses a technique for constructing two pipelines from both starting vertical shafts using a shield machine.

Japanese Patent Laid-Open No. 2005-240443

  As described above, in the conventional shield method using both starting shafts, a concrete bearing wall is installed at each of the first and second wellheads to construct a pipeline, and after the construction, the bearing wall is constructed. Has been removed. Therefore, a construction period (for example, (2 days for installation + 1 day for removal) x 2 locations = 6 days) and costs (material costs for concrete, etc. + construction costs + disposal costs) are incurred. Will do.

  The present invention has been made from the above technical background, and provides a technique that can eliminate the need for a bearing wall for receiving the reaction force of the shield machine in the shield method using both start shafts. With the goal.

  In order to solve the above problems, the starting mechanism in the shield method of the present invention according to claim 1 excavates the ground by starting a shield machine from the first and second wellheads formed in the starting shaft. A starting mechanism in a shield construction method in which a propulsion pipe is buried and a first pipe line and a second pipe line are constructed, and is a first mechanism provided integrally with a wellhead concrete that forms the first wellhead. A wellhead ring, a second wellhead ring provided integrally with the wellhead concrete forming the second wellhead, and selectively connected to the first wellhead ring and the second wellhead ring; And a reaction force when propelled by the shield machine when connected to the first wellhead ring or the second wellhead ring to which the seal ring is not connected via a connecting member Receiving the reaction force member, connecting the seal ring to the first wellhead ring, connecting the reaction force member to the second wellhead ring to construct the first pipe line, The seal ring is connected to the second wellhead ring, and the reaction member is connected to the first wellhead ring so that the second pipe line can be constructed.

  The starting mechanism in the shield method of the present invention according to claim 2 is the invention according to claim 1, wherein the first wellhead ring and the second wellhead ring have attachment pieces to which the connection member is attached, It is provided to protrude outward from the ring main body.

  The starting mechanism in the shield method of the present invention described in claim 3 is the invention according to claim 2, wherein the attachment piece is provided with a plurality of cap nuts formed with female threads, and the connecting member is The bolt which penetrated the bolt hole formed in the connection member is screwed with the cap nut, and is attached to the attachment piece.

  The starting mechanism in the shield method of the present invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the reaction force member is formed of a shape steel and faces along the starting direction. It has a pair of arrange | positioned frame part and a connection part which is formed with a shape steel and connects a pair of said frame part mutually.

  According to a fifth aspect of the present invention, there is provided a starting mechanism in the shield method according to the fourth aspect, wherein a plurality of the connecting members are provided to support a corner portion of one of the frame portions formed in a rectangular shape. It is characterized by that.

  The starting mechanism in the shield method of the present invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the first wellhead ring when the reaction force member is attached and The second wellhead ring is provided with a reinforcing material that prevents inward deformation.

  According to a seventh aspect of the present invention, there is provided a starting mechanism in the shield method according to the sixth aspect, wherein the reinforcing member is disposed at a position including a position where the connecting member is attached. To do.

  The start mechanism in the shield construction method of the present invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the first wellhead ring and the second wellhead ring are internally threaded. A plurality of cap nuts are formed, and the seal ring includes a bolt that penetrates a bolt hole formed in the seal ring and is screwed into the cap nut to form the first wellhead ring or the second cap ring. It is connected to a wellhead ring.

  In order to solve the above-mentioned problem, the pipe construction method in the shield method according to the present invention described in claim 9 is that the ground is formed by starting the shield machine from the first and second wellheads formed in the start shaft. A pipe construction method in a shield construction method in which a propulsion pipe is buried while excavating to construct a first pipe and a second pipe, and is provided integrally with a wellhead concrete forming the first wellhead. A first step of connecting a seal ring to the first wellhead ring and connecting a reaction force member to a second wellhead ring provided integrally with the wellhead concrete forming the second wellhead; A second step of constructing the first pipeline by starting the shield machine from the first wellhead while taking a reaction force with a force member, and connecting the seal ring to the second wellhead ring Together with the above A third step of connecting the reaction force member to the wellhead ring, and constructing the second pipeline by starting the shield machine from the second wellhead while taking the reaction force with the reaction force member And a fourth step.

  According to a tenth aspect of the present invention, the pipe construction method in the shield method of the present invention is the invention according to the ninth aspect, wherein in the first step and the third step, the reaction force member is placed via a connecting member. It connects with a 2nd wellhead ring or the said 1st wellhead ring, It is characterized by the above-mentioned.

  According to the present invention, in the shield method using both starting shafts, the first wellhead ring is provided at the first wellhead, the second wellhead ring is provided at the second wellhead, and the seal ring and the reaction member are alternately provided. Since the first pipe line and the second pipe line are constructed by attaching to the pipe, a bearing wall for receiving the reaction force of the shield machine is not required.

  This eliminates the need for work periods and costs for installing and removing the bearing walls at the first and second well openings, thereby reducing the work period and reducing costs.

It is a top view which illustrates the mode of the pipe line construction from the 1st wellhead of a starting vertical shaft about the starting mechanism in the shield construction method which is one embodiment of this invention. It is a side view which shows the mode of the pipeline construction from the 1st wellhead of a starting vertical shaft about the starting mechanism in the shield construction method which is one embodiment of this invention. It is a top view which illustrates the mode of the pipe line construction from the 2nd wellhead of a starting vertical shaft about the starting mechanism in the shield construction method which is one embodiment of this invention. It is a side view which illustrates the mode of the pipe line construction from the 2nd wellhead of a starting vertical shaft about the starting mechanism in the shield construction method which is one embodiment of the present invention. It is a side view which shows the wellhead ring and seal ring in the starting mechanism in the shield construction method which is one embodiment of this invention. FIG. 6 is a plan view of FIG. 5. It is a side view which expands and shows the principal part of FIG. It is the front view seen from the II line | wire of FIG. It is the front view seen from the II-II line of FIG. It is the front view seen from the III-III line of FIG. It is a front view which shows the reaction force member connected to the wellhead ring in the starting mechanism in the shield method which is one embodiment of this invention. It is a side view of FIG. It is a front view which shows the connection piece for connecting a reaction force member to a wellhead ring. It is a front view which shows the positional relationship of a reaction force member and a temporary segment.

  Hereinafter, an embodiment as an example of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  FIG. 1 is a plan view illustratively showing the state of the construction of a pipeline from the first wellhead of a start shaft for the start mechanism in the shield method according to an embodiment of the present invention, FIG. 2 is a side view of FIG. 3 is a plan view illustratively showing the construction of the pipeline from the second wellhead of the start shaft for the start mechanism in the shield method according to one embodiment of the present invention, and FIG. 4 is a side view of FIG.

  As shown in FIGS. 1 to 4, in this embodiment, the shield machine 2 is installed from two wellheads (first wellhead H1 and second wellhead H2) formed in the start shaft 1 dug in the ground. This is a starting mechanism in a shield method in which a propulsion pipe is buried while starting and excavating the ground to construct two pipe lines (first pipe line and second pipe line).

  Both the first wellhead H1 and the second wellhead H2 are made of concrete (wellhead concrete). And as shown in Drawing 1 and Drawing 2, when constructing the 1st pipe line from the 1st wellhead H1, seal ring SR for stopping a wellhead is attached to the 1st wellhead H1, A reaction force member 4 that receives a reaction force when the shield machine 2 propels is connected to the second wellhead H2. As shown in FIGS. 3 and 4, when the second pipe is constructed from the second wellhead H2, the seal ring SR is attached to the second wellhead H2, and the reaction force member 4 is the first member. To the wellhead H1.

  A propulsion base 3 is installed at the bottom of the start shaft 1 dug in the ground. And the shield machine 2 installed on this propulsion stand 3 excavates the ground from the first wellhead H1 or the second wellhead H2 while taking the reaction force by the reaction force member 4.

  1 and 2 show a shield machine 2 that excavates the ground from the first wellhead H1. 3 and 4, the shield machine 2 enters the second pipeline from the second wellhead H <b> 2, and a temporary segment 5 is installed in the start shaft 1.

  The shield machine 2 according to the present embodiment is configured so that the pressure of the muddy water pumped into the muddy water chamber 2b provided behind the cutter head 2a is set to a pressure corresponding to the earth pressure of the face and the groundwater pressure, while stabilizing the face. This is a muddy water shield machine that excavates a natural ground with a bit in front of the cutter head 2a to form an excavation pit by rotating the head 2a against the face. On the inner periphery of the excavation mine formed behind the shield machine 2, a pipeline in which propulsion pipes (not shown), which are fume pipes made of, for example, reinforced concrete, are connected in cascade.

  The shield machine 2 includes a front body plate 2c-1 including the above-described cutter head 2a and a rear body plate 2c-2 behind the front body plate 2c-1. In the machine constituted by the front trunk plate 2c-1 and the rear trunk plate 2c-2, a cutter driving body 2d, a bent jack 2e, a shield jack 2f, a mud pipe 2g, a mud pipe 2h, and the like are installed. ing.

  The cutter driver 2d is a drive source that rotates the cutter head 2a. The middle-folded jack 2e is a device that connects the front trunk plate 2c-1 and the rear trunk plate 2c-2 and corrects the propulsion direction of the shield machine 2. The shield jack 2f is a device that generates a propulsive force for advancing the shield machine 2 by applying a reaction force to the propulsion pipe laid on the inner periphery of the excavation mine. The mud pipe 2g is a pipe for supplying mud water into the mud chamber 2b. And the mud drain pipe 2h is piping which discharges the mud containing the excavation earth and sand in the mud chamber 2b out of the excavation pit.

  The wellhead concrete that forms the first wellhead H1 and the wellhead concrete that forms the second wellhead H2 are integrally provided with a first wellhead ring HR1 and a second wellhead ring HR2, respectively. The seal ring SR is selectively connected to the first wellhead ring HR1 and the second wellhead ring HR2.

  Here, the wellhead rings HR1 and HR2 and the seal ring SR connected to the wellhead rings HR1 and HR2 will be described with reference to FIGS. 5 is a side view showing the wellhead ring and the seal ring, FIG. 6 is a plan view of FIG. 5, FIG. 7 is a side view showing an enlarged main part of FIG. 5, and FIG. FIG. 9 is a front view seen from the line II-II in FIG. 5, and FIG. 10 is a front view seen from the line III-III in FIG.

  As shown in these drawings, the wellhead rings HR1 and HR2 project outward from four locations of the ring main body portion HR-10, the base portion HR-20 that supports the ring main body portion HR-10, and the ring main body portion. And an attachment piece HR-30 provided. The attachment piece HR-30 is for attaching a connection piece 6 (connection member) to be described later for connecting the reaction force member 4 to the wellhead rings HR1 and HR2.

  The ring main body portion HR-10 includes an annular cylindrical portion HR-11, an annular front flange HR-12 bent outward from the front portion of the cylindrical portion HR-11, and a cylindrical portion HR-11. And an annular rear flange HR-13 bent inward from the rear portion. In addition, a plurality of steel reinforcing materials HR-14 for preventing inward deformation are provided in the hollow interior, spanning in the radial direction. Further, a plurality of reinforcing ribs HR-15 extending in the axial direction are provided on the outer side of the cylindrical portion HR-11 in the circumferential direction, and the axial direction for sealing the wellhead is provided in the front flange HR-12. A plurality of bendable flapper gates G are attached in the circumferential direction.

  The reinforcing material HR-14 is disposed when the reaction force member 4 is attached to the wellhead rings HR1 and HR2. When the reaction force member 4 is not attached, that is, the shield machine 2 enters. Sometimes it cannot be installed.

  On the other hand, the seal ring SR includes an annular cylindrical part SR-11, an annular front flange SR-12 bent inward from the front part of the cylindrical part SR-11, and a rear part of the cylindrical part SR-11. And an annular rear flange SR-13 bent outward. Further, a plurality of reinforcing ribs SR-15 extending in the axial direction are provided inside the cylindrical body portion SR-11 in the circumferential direction, and the front flange SR-12 has an axial direction for sealing the wellhead. A plurality of bendable flapper gates G are attached in the circumferential direction.

  Here, the wellhead rings HR1 and HR2 (specifically, the front flanges HR-12 of the wellhead rings HR1 and HR2) are provided with a plurality of cap nuts N formed with female threads over the entire circumference. Further, a bolt hole is formed at a position corresponding to the cap nut N in the seal ring SR (specifically, the rear flange SR-13 of the seal ring SR). Then, when the bolt B penetrating the bolt hole of the seal ring SR is screwed with the cap nut N of the wellhead rings HR1 and HR2, the seal ring SR is connected to the first wellhead ring HR1 or the second wellhead ring HR2. Has been.

  As shown in detail in FIGS. 7 and 9, the inner periphery of the installation position of the cap nut N is the attachment position of the flapper gate G in the annular front flange HR-12 of the wellhead rings HR1 and HR2. Yes. A cylindrical portion SR-11 of the seal ring SR is attached between the installation position of the cap nut N and the attachment position of the flapper gate G.

  Thus, by using the structure using the cap nut N for the wellhead rings HR1 and HR2, the seal ring SR can be easily attached to and detached from the wellhead rings HR1 and HR2 provided integrally with the wellhead concrete. Become.

  Next, the reaction force member 4 connected to the first wellhead ring HR1 and the second wellhead ring HR2 will be described with reference to FIGS. 9 and 11 to 14. 11 is a front view showing a reaction force member connected to the wellhead ring, FIG. 12 is a side view of FIG. 11, FIG. 13 is a front view showing a connection piece for connecting the reaction force member to the wellhead ring, and FIG. It is a front view which shows the positional relationship of a reaction force member and a temporary segment.

  As described above, the reaction force member 4 is connected to the first wellhead ring HR1 or the second wellhead ring HR2 to which the seal ring SR is not coupled via the connection piece 6 that is a connecting member.

  As shown in these drawings, the reaction member 4 is formed of a combination of section steel such as H-section steel cut to a predetermined length, and is formed in a rectangular shape and is opposed to each other along the starting direction. It is comprised by frame part 4a, 4a and the connection part 4b which connects these pair of frame parts 4a, 4a mutually. In the present embodiment, the frame portions 4a and 4a are rectangular for ease of assembly, but may have a shape other than a rectangle (for example, a triangle or a hexagon).

  Further, a plurality (four) of the connection pieces 6 are provided so as to support the corners of the one frame body portion 4a formed in a rectangular shape in this way. The connection piece 6 is also formed of a combination of section steel such as H-section steel cut to a predetermined length, and has a substantially L shape when viewed from the front as shown in FIG. In addition, you may form the connection piece 6 and the above-mentioned reaction force member 4 with shape steels other than H-section steel, such as I-section steel and T-section steel.

  As described above, the four connection pieces 6 are respectively attached to the four attachment pieces HR-30 provided so as to protrude outward from the four portions of the ring body portions of the wellhead rings HR1 and HR2. By bolting the corners of the frame body portion 4 a constituting the reaction force member 4 to the connection piece 6, the reaction force member 4 is connected to the wellhead rings HR <b> 1 and HR <b> 2 via the connection piece 6.

  In addition, when the reaction force member 4 can be directly connected to the wellhead rings HR1 and HR2, the connection piece 6 can be omitted.

  In the present embodiment, the mounting piece HR-30 is provided with a plurality of cap nuts N formed with female threads. Further, the connection piece 6 is formed with a bolt hole at a position corresponding to the cap nut N. And the connection piece 6 is couple | bonded with the attachment piece HR-30 by the volt | bolt which penetrated the said bolt hole of the connection piece 6 screwed with the cap nut N of the attachment piece HR-30. And with such a structure, it becomes possible to attach or detach the connection piece 6 easily with respect to the attachment piece HR-30.

  As shown in the figure, the connection piece 6 supports a corner portion of one frame body portion 4a formed in a rectangular shape. More specifically, the two outer sides forming the right angle of the connection piece 6 form the two outer sides forming the right angle of the attachment piece HR-30 and the right angle of the corner in the frame portion 4a of the reaction member 4. Are connected in a positional relationship that matches the two outer sides. As a result, when the reaction force at the start of the shield machine 2 is applied to the reaction force member 4 via the temporary segment 5 in the start shaft 1, as shown in FIG. It is designed to be evenly distributed to the mounting pieces HR-30 at the locations.

  In FIG. 14, the auxiliary frame 4c for supporting the temporary segment 5 at a location that cannot be supported by the frame body portion 4a is provided at four locations inside the frame body portion 4a with respect to the frame body portion 4a. It is provided diagonally. However, although the auxiliary frame 4c can be omitted, it is desirable to provide the auxiliary frame 4c when the frame body portion 4a cannot support the entire circumference of the temporary segment 5.

  Here, as shown in FIG. 9, a part of the reinforcing material HR-14 described above that prevents the inward deformation of the wellhead rings HR1 and HR2 is the position where the attachment piece HR-30 is provided, that is, the connection piece 6 It is arranged at the attached position. As described above, since the reaction force is applied to the four attachment pieces HR-30 via the connection piece 6, the deformation of the wellhead rings HR1 and HR2 is further improved by reinforcing this position with the reinforcing material HR-14. It is surely prevented.

  However, the arrangement of the reinforcing material HR-14 is not limited to this, and if there is no risk of deformation of the wellhead rings HR1 and HR2 without the reinforcing material HR-14, the reinforcing material HR-14 is used. It may be omitted.

  Next, a method of constructing a pipeline (first pipeline / second pipeline) in the starting mechanism configured as described above will be described.

  First, the seal ring SR is connected to the first wellhead ring HR1 of the first wellhead H1 formed in the start shaft 1, and the attachment piece HR- provided to the second wellhead ring HR2 of the second wellhead H2 The connection piece 6 is attached to 30 and the reaction force member 4 is connected (first step).

  And while taking the reaction force with the reaction force member 4, the shield machine 2 is started from the 1st wellhead H1, and a 1st pipe line is constructed | assembled (2nd process).

  After the construction of the first pipe line is finished, the seal ring SR connected to the first wellhead ring HR1 is then removed and connected to the second wellhead ring HR2 of the second wellhead H2, The connecting piece 6 attached to the second wellhead ring HR2 is removed and attached to the attachment piece HR-30 provided on the first wellhead ring HR1 of the first wellhead H1, and the reaction member 4 is attached to the first wellhead ring. Connect to HR1 (third step).

  Then, the direction of the shield machine 2 is reversed and lowered to the start shaft 1, and the shield machine 2 is started from the second wellhead H2 while taking the reaction force with the reaction member 4 to construct the second pipe line. (Fourth step).

  In addition, in the 1st process and the 3rd process, although the reaction force member 4 is connected to 2nd wellhead ring HR2 or 1st wellhead ring HR1 via the connection piece 6, the connection piece 6 can be abbreviate | omitted. In this case, the reaction force member 4 is directly connected to the wellhead rings HR1 and HR2.

  Thus, according to the present embodiment, in the shield construction method using both starting shafts, the first wellhead ring HR1 is provided at the first wellhead H1, and the second wellhead ring HR2 is provided at the second wellhead H2. Since the first ring and the second pipe are constructed by alternately attaching the seal ring SR and the reaction member 4, the bearing wall for receiving the reaction force of the shield machine 2 Is no longer necessary.

  This eliminates the need for a process and cost for installing and removing the bearing walls at the first and second wellheads H1 and H2, respectively, thus enabling shortening of the construction period and cost reduction. Become.

  Although the invention made by the present inventor has been specifically described based on the embodiment, the embodiment disclosed in this specification is an example in all respects and is limited to the disclosed technology. is not. That is, the technical scope of the present invention should not be construed restrictively based on the description in the above-described embodiment, but should be construed according to the description of the scope of claims. All modifications are included without departing from the technical scope equivalent to the described technique and the gist of the claims.

  In the above description, the case where the present invention is applied to a muddy water type shield machine has been described. However, the present invention is not limited to this. For example, the drilling earth and sand and the additive are kneaded in the chamber behind the cutter head. Mud pressure type shield excavator, etc. that excavates in a state filled with mud generated by mixing and generates mud pressure and opposes the mud pressure against the earth pressure of the face. It can also be applied to shield machines.

DESCRIPTION OF SYMBOLS 1 Start shaft 2 Shield machine 2a Cutter head 3 Propulsion stand 4 Reaction force member 4a Frame part 4b Connection part 4c Auxiliary frame 6 Temporary segment 6 Connection piece B Bolt G Flapper gate H1 1st wellhead H2 2nd wellhead HR1 1st 1 wellhead ring HR2 2nd wellhead ring HR-10 ring main body part HR-11 cylindrical body part HR-12 front flange HR-13 rear flange HR-14 reinforcement HR-15 rib HR-20 pedestal part HR-30 Mounting piece N Cap nut SR Seal ring SR-11 Cylindrical part SR-12 Front flange SR-13 Rear flange SR-15 Rib

Claims (10)

A shield that constructs a first pipe line and a second pipe line by burying a propulsion pipe while excavating the ground by starting a shield machine from the first and second wellheads formed in the start shaft A starting mechanism in the construction method,
A first wellhead ring provided integrally with the wellhead concrete forming the first wellhead;
A second wellhead ring provided integrally with the wellhead concrete forming the second wellhead;
A seal ring selectively connected to the first wellhead ring and the second wellhead ring to stop the wellhead;
A reaction force member connected to the first wellhead ring or the second wellhead ring to which the seal ring is not connected via a connection member and receiving a reaction force when the shield machine is propelled. ,
The seal ring is connected to the first wellhead ring, the reaction member is connected to the second wellhead ring to construct the first pipeline, and then the second wellhead ring is connected to the second wellhead ring. A seal ring is connected, and the reaction member is connected to the first wellhead ring so that the second pipe line can be constructed.
The starting mechanism in the shield construction method. In the first wellhead ring and the second wellhead ring,
An attachment piece to which the connection member is attached is provided so as to protrude outward from the ring body.
The starting mechanism in the shield method according to claim 1. The mounting piece is provided with a plurality of cap nuts formed with female threads,
The connecting member is attached to the attachment piece by screwing a bolt penetrating a bolt hole formed in the connecting member with the cap nut.
The start mechanism in the shield method according to claim 2. The reaction force member is
A pair of frame parts formed of shape steel and arranged to face each other along the starting direction;
A connecting portion that is formed of a shape steel and connects the pair of frame bodies to each other;
Having
The starting mechanism in the shield method according to any one of claims 1 to 3, wherein The connecting member is
A plurality of corner portions of the one frame body portion formed in a rectangle are supported and provided.
The starting mechanism in the shield method according to claim 4. The first wellhead ring and the second wellhead ring when the reaction force member is attached are provided with a reinforcing material that prevents inward deformation,
The starting mechanism in the shield method according to any one of claims 1 to 5, wherein The reinforcing material is disposed at a position including a position where the connection member is attached.
The starting mechanism in the shield method according to claim 6. The first wellhead ring and the second wellhead ring are provided with a plurality of cap nuts formed with female threads,
In the seal ring, a bolt penetrating a bolt hole formed in the seal ring is screwed with the cap nut and connected to the first wellhead ring or the second wellhead ring.
The starting mechanism in the shield method according to any one of claims 1 to 7, A shield that constructs a first pipe line and a second pipe line by burying a propulsion pipe while excavating the ground by starting a shield machine from the first and second wellheads formed in the start shaft It is a pipe construction method in the construction method,
A seal ring is connected to a first wellhead ring provided integrally with the wellhead concrete forming the first wellhead, and a second wellhead ring provided integrally with the wellhead concrete forming the second wellhead A first step of connecting a reaction force member to
A second step of constructing the first pipeline by starting the shield machine from the first wellhead while taking a reaction force with the reaction member;
A third step of connecting the seal ring to the second wellhead ring and connecting the reaction member to the first wellhead ring;
A fourth step of constructing the second pipeline by starting the shield machine from the second wellhead while taking a reaction force with the reaction member;
A conduit construction method in a shield method characterized by comprising: In the first step and the third step,
Connecting the reaction force member to the second wellhead ring or the first wellhead ring via a connecting member;
The conduit construction method in the shield method according to claim 9.

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