Method for replacing tail seal of shield excavator and shield excavator

Abstract

To provide a method to replace a tail seal of a shield excavator, which enables a tunnel with a small bending radius to be constructed.SOLUTION: An excavator body is promoted forward by elongation of a plurality of shield jacks 15 using an existing segment ring 30 as a reaction receiver and a new segment ring is sequentially installed forward to construct a tunnel. A tail seal 61, which is disposed on a rear part of a skin plate 10 of the excavator body and seals between an outer peripheral surface of the skin plate and an inner peripheral surface of the segment ring 30, is replaced during construction of the tunnel. On an elector 50, an attachment is replaced to a piece guide attachment capable of guiding pieces of a segment, then, pieces constituting a segment ring 31 are fixed to a spreader of a rod 15a of the shield jack 15 while guiding a plurality of pieces by a piece support attachment. The pieces are moved forward by contracting the rod 15a and the tail seal 61 is replaced through a space generated thereby.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for replacing a tail seal of a shield excavator and to a shield excavator. [Background technology]

[0002] To construct tunnels, shield tunneling machines are used, which excavate the ground with the front end of the machine body and assemble the segment rings at the rear of the machine body, repeating this process ring by ring.Shield tunneling machines are equipped with tail seals such as tail brushes to seal the gap between the inner surface of the rear part of the machine body and the outer surfaces of the segment rings.

[0003] When constructing long-distance tunnels, there was a risk that the tail seal would deteriorate or be damaged, leading to problems such as malfunctions of the segment rings and abnormalities in jack thrust, making it necessary to replace the tail seal while the tunnel was being excavated.

[0004] Therefore, Patent Document 1 discloses a technology in which a new tail seal ring is fixed to the front end of the original tail seal ring, and the rod of a shield jack is extended to move the tail seal ring rearward, and then the rod is shortened to remove the original tail seal ring. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-184489 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the technology described in Patent Document 1, the stroke of the shield jack rod must be longer than the length of the tail seal ring, which causes a problem in that tunnels with small bending radii cannot be constructed.

[0007] In view of the above, an object of the present invention is to provide a method for replacing a tail seal of a shield tunneling machine and a shield tunneling machine that are capable of constructing tunnels with small bending radii. [Means for solving the problem]

[0008] The method for replacing tail seals of a shield excavator of the present invention involves propelling the excavator toward the tunnel face by extending the rods of a plurality of propulsion jacks, with existing segment rings consisting of pieces divided circumferentially as reaction forces, and sequentially installing new segment rings on the tunnel face side of the existing segment rings. This method replaces tail seals that are provided at the rear of the trunk of the excavator body and seal the gap between the inner surface of the trunk and the outer surface of the existing segment rings during tunnel construction. The method is characterized in that the pieces are held and the segment rings are assembled using an assembly device having a piece assembly section that can detachably hold the pieces, the piece assembly section of the assembly device is replaced with a piece guide section that can guide the pieces, and then, while the pieces are guided by the piece guide section, the pieces that make up the segment ring located inside the tail seal to be replaced are fixed to spreaders on the rods of the propulsion jacks, and the rods are contracted to move the pieces toward the tunnel face. The tail seal to be replaced is replaced through the space created by the movement of the pieces.

[0009] According to the method for replacing a tail seal for a shield tunneling machine of the present invention, the piece located inside the tail seal to be replaced is moved toward the tunnel face by contracting the rod of the propulsion jack, and the tail seal is replaced through the space created by this movement. As a result, the amount of rod contraction required to replace the tail seal is sufficient as long as it is possible to create a space in which the tail seal can be replaced, and compared to the technology described in Patent Document 1, it is possible to reduce the rod stroke and construct a tunnel with a small bending radius.

[0010] Then, while the pieces are guided by the piece guide section, the segment ring located inside the tail seal to be replaced is moved toward the face. Note that when guiding the upper piece, the piece is preferably supported by the piece guide section, and when guiding the middle and lower pieces, the piece is preferably configured to be able to slide along the piece guide section. This allows the pieces to be moved smoothly using existing assembly equipment and prevents the remaining pieces from falling off.

[0011] In the method for replacing the tail seal of a shield excavator of the present invention, it is preferable to replace the piece guide portion of the assembly device with a waterstop assembly portion capable of guiding a first waterstop that covers the axially exposed surface of the piece exposed by the movement and the space between the outer surface of the segment ring and the inner surface of the skin plate of the excavator body, and a second waterstop that covers the space between the circumferentially exposed surface of the piece exposed by the movement and the outer surface of the segment ring, and then guide the first waterstop and the second waterstop using the waterstop assembly portion to assemble the first waterstop and the second waterstop.

[0012] In this case, the waterstop can be easily assembled using an existing assembly device.

[0013] Furthermore, in the method for replacing the tail seal of a shield excavator of the present invention, it is preferable to replace the piece guide portion or the waterstop assembly portion of the assembly device with a spacer placement portion that detachably holds a spacer to be interposed between the moved piece and the piece located on the shaft side of the piece, and then hold the spacer by the spacer placement portion and install the spacer between the moved piece and the piece located on the shaft side of the piece.

[0014] In this case, the spacer can be easily assembled using an existing assembly device.

[0015] The shield tunneling machine of the present invention is a shield tunneling machine that propels the excavation machine body toward the tunnel face by extending the rods of multiple propulsion jacks, which use existing segment rings consisting of pieces divided circumferentially as a reaction force, and constructs a tunnel by sequentially installing the segment rings toward the tunnel face, and is characterized in that it is equipped with a tail seal that is provided at the rear of the body of the excavation machine body and seals the space between the inner surface of the body and the outer surface of the existing segment ring, and an assembly device that is provided inside the excavation machine body and has a piece assembly part that can hold the pieces detachably, and the piece assembly part of the assembly device is replaceable with a piece guide part that can guide the pieces.

[0016] With the shield tunneling machine of the present invention, it is possible to move the segment ring located inside the tail seal to be replaced toward the tunnel face while guiding the pieces with the piece guide section. This makes it possible to move the pieces smoothly using existing assembly equipment and prevent the remaining pieces from falling off.

[0017] In the shield tunneling machine of the present invention, it is preferable that the piece assembly portion of the assembly device can be replaced with a waterstop assembly portion capable of guiding a waterstop that covers the exposed surface of the piece and the inner surface of the skin plate.

[0018] In this case, the waterstop can be easily assembled using an existing assembly device.

[0019] In addition, in the shield tunneling machine of the present invention, it is preferable that the piece assembly portion of the assembly device can be replaced with a spacer arrangement portion that can detachably hold spacers to be interposed between the pieces spaced apart in the direction from the face side toward the shaft side.

[0020] In this case, the spacer can be easily assembled using an existing assembly device. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic longitudinal cross-sectional view of a shield excavator used in a method for replacing a tail seal of a shield excavator according to an embodiment of the present invention. [Figure 2] This is a schematic exploded view seen from the central axis side of the shield tunneling machine, showing the arrangement of the pieces that make up the segment ring when replacing the tail seal. [Figure 3] This is a schematic exploded view of the shield tunneling machine as seen from the central axis side, showing the first two pieces pulled out. [Figure 4] Schematic longitudinal cross-sectional view of an erector with a piece guide attachment. [Figure 5] Schematic longitudinal cross-sectional view of an erector equipped with a waterstop assembly attachment. [Figure 6] FIG. 1 is a schematic longitudinal cross-sectional view of an erector equipped with a spacer arrangement attachment. [Figure 7] This is a schematic development view of the shield tunneling machine as seen from the central axis side, showing the state in which a spacer has been placed in the space created by the first two pieces that were pulled out. [Figure 8] This is a schematic exploded view of the shield tunneling machine as seen from the central axis side, showing the state in which the following two pieces have been pulled out. [Figure 9] This is a schematic exploded view of the shield tunneling machine as seen from the central axis side, showing the last two pieces pulled out. DETAILED DESCRIPTION OF THE INVENTION

[0022] A shield excavator 100 used when carrying out a method for replacing a tail seal of a shield excavator according to an embodiment of the present invention will be described with reference to the drawings.

[0023] As shown in Figure 1, the shield tunneling machine 100 comprises a skin plate (shield tube) 10 and a drilling unit 20 assembled to the skin plate 10. The skin plate 10 is composed of a front skin plate (front body) 11 and a rear skin plate (rear body) 12. The skin plate 10 and the drilling unit 20 correspond to the tunneling machine body of the present invention, and the skin plate 10 corresponds to the body of the present invention.

[0024] A spherical joint portion 13 that fits into the rear end portion of the front skin plate 11 is provided at the front end of the rear skin plate 12, allowing the front skin plate 11 to bend freely in any direction relative to the rear skin plate 12. A plurality of articulating jacks 14 that connect the front skin plate 11 and the rear skin plate 12 are provided at intervals in the circumferential direction, and these articulating jacks 14 can be used to adjust the direction of the front skin plate 12, i.e., the excavation direction of the shield tunneling machine 100.

[0025] A plurality of propulsion jacks (shield jacks) 15 are attached to the rear skin plate 12 at intervals in the circumferential direction, and these propel the shield excavator 100 forward by using the existing segment ring 30 as a reaction force receiver.

[0026] 2, an erector 50 is disposed inside the rear skin plate 12, which assembles ring-shaped segment rings 31 and the like using pieces 41 and the like onto the inner wall surface of the excavated tunnel. The erector 50 corresponds to the assembly device of the present invention.

[0027] The excavator body is advanced by the propulsion jack, using the existing segment ring 30 as a reaction force receiver, and a new segment ring is installed between the rear (shaft side) of the propulsion jack 15 and the tip of the existing segment ring 30. The segment ring 31, etc., is made up of multiple, in this case six, steel pieces 41, etc., connected circumferentially, and is in the shape of a short, approximately circular tube.

[0028] The pieces 41, etc. are carried into the shield tunneling machine 100, and the pieces 41, etc. are assembled into a ring shape using an erector 50 arranged in the shield tunneling machine 100. Since the pieces 41, etc. are heavy objects, assembly work is carried out inside the shield tunneling machine 100 using an erector 50 equipped with a piece assembly attachment 51 that can assemble the pieces 41, etc.

[0029] Although not shown in detail, each piece 41 etc. has a held portion such as a recess or a through-hole formed therein so that it can be held by a protruding body such as a pin provided on a sled-shaped support member 51a of the piece assembling attachment 51. Each piece 41 etc. is held by the piece assembling attachment 51 by being placed on the support member 51a with its held portion held by the protruding body. The piece assembling attachment 51 corresponds to the piece assembling portion of the present invention.

[0030] The excavation unit 20 has a partition wall 21 and a cutter head 22 that excavates the face forward (on the face side) of the front end of the skin plate 10. The cutter head 22 is supported by the partition wall 21.

[0031] A drive unit 23 that rotates and drives the cutter head 22 is provided on the back surface of the partition wall 21. The drive unit 23 is composed of a drive motor, a reducer, gears, etc., and the drive force of the drive unit 23 drives and rotates the cutter head 22 with high torque via a drive shaft 24.

[0032] The space between the partition wall 21 and the cutter head 22 forms a compartment 25. The compartment 25 is filled with excavated soil and mud water to counteract the earth pressure from the working face. A soil transport device 26 communicating with the compartment 25 is provided on the rear side of the partition wall 21. The soil transport device 26, consisting of a mud transport pipe 26a and a mud discharge pipe 26b, reaches the departure shaft at the rear.

[0033] Tail seals 61 to 63 are attached to the rear of the rear skin plate 12 to seal the gap between it and the outer circumferential surface of the existing segment ring 30. The tail seals 61 to 63 also include brush-shaped tail brushes.

[0034] Each tail seal 61-63 is annular as a whole, and is provided so that its inner periphery contacts the outer periphery of the segment ring 30. When the face side is the front and the shaft side is the rear, the tail seals 61-63 are provided in multiple stages (three stages in this case) spaced apart in the front-to-rear direction. Although not shown in detail, each tail seal 61-63 is fixed, for example, by bolts to a tail plate 12a that is divided circumferentially for each stage, and each tail plate 12a is fixed to the rear skin plate 12 by welding, bolts, or the like. In this way, each tail seal 61-63 is replaceable with respect to the tail plate.

[0035] When replacing tail seals 61, 62 during tunnel construction, pieces 41, etc. that make up segment rings 31, etc. are positioned so that they are in the predetermined positions relative to the tail seals 61, 62 to be replaced, as shown in Figure 2. In other words, it is possible to replace tail seals 61, 62 in the predetermined positions in a tunnel under construction in which predetermined pieces 41, etc. are positioned in the predetermined positions. Figures 2 and 3 are schematic developments viewed from the central axis side of the shield tunneling machine 100.

[0036] Here, we will explain the case where the tail seal 61 of the step located closest to the face side is replaced. When constructing a curve, the clearance between the inner surface of the rear skin plate 12 and the segment ring 31 becomes narrow, so this tail seal 61 rubs against the segment ring 31 and is prone to wear, so it is the seal that needs to be replaced most frequently. Tail seal 62 may be replaced at the same time as tail seal 61. Note that when tail seal 63 is replaced, the shaft side will need to be sealed off separately.

[0037] Each piece 41 constituting the segment ring 31 located inside the tail seal 61 to be replaced (towards the central axis of the shield excavator 100) is a steel piece, and is formed with one injection port 41a for injecting a waterproofing agent. However, it is not necessary for these pieces 41 to be formed with an injection port 41a.

[0038] Each of the pieces 43, 44 constituting the segment rings 33, 34 located a predetermined number of stages closer to the shaft than the segment ring 31 located inward of the tail seal 61 to be replaced is also a steel piece, and is formed with a plurality of injection ports 43a, 43b, 44a spaced apart in the circumferential direction. Here, each of the pieces 43 constituting the segment ring 33 located two rows closer to the shaft than the segment ring 31 is provided with a plurality of injection ports 43a for injecting a consolidating lubricant and a plurality of injection ports 43b for injecting a waterproofing agent, spaced apart in the circumferential direction.

[0039] This segment ring 33 is located closer to the shaft than the tail seal 63, which is located closest to the shaft. Note that each piece 44 constituting the segment ring 34 that is one shaft closer to this segment ring 33, i.e., the segment ring that is located three shafts closer to the shaft than the segment ring located inward of the tail seal 61 to be replaced, also has a plurality of injection ports 44a for injecting waterproofing agent that are spaced apart in the circumferential direction.

[0040] Each of the injection ports 41a, 43a, 43b, and 44a is equipped with a check valve (not shown in detail) and is normally sealed with a plug. When injecting the caking lubricant or waterproofing agent, the plug is removed, and after injection, the injection ports 41a, 43a, 43b, and 44a are sealed with the plug.

[0041] Although not shown, all pieces are provided with at least one injection port for injecting a backfilling agent into the gap between the natural ground and the segment ring 30. Meanwhile, in the above-mentioned pieces 41 to 44, not only is the backfilling agent injected, but it is also necessary to waterproof the gap between the segment rings 32 to 34 and the natural ground on the shaft side of the tail seal 63. This waterproofing must be performed reliably around the entire circumference, so multiple injection ports 43a, 43b, and 44a are provided spaced apart circumferentially. Note that injection port 41a is provided for injecting a waterproofing agent in an emergency, and therefore only one is provided on each piece 41.

[0042] The number of injection ports 43a provided in each piece 43 constituting the segment ring 33 located two shaft sides closer to the segment ring 31 located inward of the tail seal 61 to be replaced is preferably greater than or equal to the number of injection ports 41a, 44a provided in the other pieces 41, 44. This makes it possible to reliably seal water between the segment ring 33, which is most in need of watertightness and the natural ground, and which does not have any tail seals 61-63 on the shaft side.

[0043] Hereinafter, a method for replacing a tail seal of a shield tunneling machine according to an embodiment of the present invention will be described using the above-described shield tunneling machine 100.

[0044] First, as shown in Figure 2, the positional relationship of the segment rings 31 to 34 with respect to the tail seal 61 to be replaced is set to the predetermined relationship described above. In this way, when it is time to replace the tail seal 61, a tunnel is constructed in advance using the predetermined segment rings 31 to 34.

[0045] Then, a consolidating lubricant is injected from each injection port 43a of the pieces 43 constituting the segment ring 33 located closer to the shaft than the tail seal 63 located closest to the shaft, and then a water-stopping agent is injected from injection port 43b. This makes it possible to stop the flow of groundwater from the shaft side of the tail seal 63. Since the water-stopping agent cannot be injected if a backfilling agent is injected, a consolidating lubricant, which is a low-strength filler, is used to prevent the ground from collapsing, and then the water-stopping agent is injected to replace the consolidating lubricant. Finally, a backfilling agent is injected.

[0046] Next, as shown in Figure 3, some of the pieces 41 that make up the segment ring 31 located inside the tail seal 61 to be replaced are pulled out toward the face. Here, we will explain the case where piece 41-1 located at the top of the segment ring 31 and the adjacent piece 41-2 are pulled out first.

[0047] It is preferable to apply a lubricant to both circumferential surfaces of the pieces 41-1 and 41-2 that come into contact with the adjacent pieces in advance, and to embed a sealant in both surfaces. This makes it possible to reduce damage that occurs between the pieces 41-1 and 41-2 when they are pulled out.

[0048] At this time, the worker removes the piece assembly attachment 51 and instead attaches a piece guide attachment 52 to the erector 50, as shown in FIG. 4. The worker then operates the erector 50 to pull out the pieces 41-1 and 41-2 to secure a space S. This space S includes the space where the pieces 41-1 and 41-2 originally existed. The piece guide attachment 52 is equipped with a sled-shaped guide member 52a that guides the pieces 41-1 and 41-2 on a guide surface. The pieces 41-1 and 41-2 are guided by being pressed against the upper surface of the guide member 52a, thereby preventing the remaining pieces 42-1, 42-2, 42-6, etc. from falling off. Preferably, the guide member 52a supports the upper pieces 41-1 and 41-2 when guiding them, and allows the pieces 41-3 to 41-6 located in the middle and lower portions to slide along the guide member 52a when guiding them. The piece guide attachment 52 corresponds to the piece guide portion of the present invention.

[0049] While holding down the remaining pieces 41-3 to 41-6 with thrust jacks 15-3 to 15-6 to prevent them from falling off, the top piece 41-1 and the adjacent piece 41-2 on one side are pulled out first. The top piece 41-1 has both sides inclined so that it tapers toward the face. The adjacent piece 41-2 has one side inclined to correspond to the side that contacts piece 41-1.

[0050] To pull out the jack, first, the top piece 41-1 is fixed to the spreader attached to the rear end of the rod 15a-1 of the corresponding propulsion jack 15-1. Then, the piece 41-2 adjacent to the top piece 41-1 is fixed to the spreader attached to the end of the rod 15a-2 of the corresponding propulsion jack 15-2. The spreaders attached to the ends of the rods 15a-1, etc., can be fixed to the pieces 41-1, etc. using known detachable fixing means such as a clamp or a vice.

[0051] Thereafter, the rod 15a-1 of the propulsion jack 15-1 is retracted, thereby pulling out the top piece 41-1. Then, at the same time as or after this, the rod 15a-2 of the propulsion jack 15-2 is retracted, thereby pulling out the piece 41-2.

[0052] The retraction stroke of the rods 15a-1 and 15a-2 when they are pulled out is set to a distance longer than the length of the spacers 81 and 82, which will be described later. However, the retraction stroke when the top piece 41-1 is pulled out is set to a distance slightly longer than the retraction stroke when the piece 41-2 is pulled out, so that a gap is created between the top piece 41-1 and the piece 41-2 when pulled out.

[0053] Furthermore, after replacing the tail seal 61, if water leaks out from the joints between the pieces 41 that make up the segment ring 31 due to damage to the tail seal 61 when the sealing portion of the tail seal 61 passes through the segment ring 31, water leakage can be prevented in an emergency by injecting a water-stopping agent through each injection port 41a of the piece 41.

[0054] Next, the worker removes the piece guide attachment 52 and instead attaches the waterstop plate assembling attachment 53 to the erector 50, as shown in Figure 5. The worker then operates the erector 50 to install the waterstop plate 70, as described below.

[0055] The waterstop plate assembling attachment 53 is equipped with a gripping member 53a that can grip the waterstop plate 70. By gripping the waterstop plate 70 with this gripping member 53a, the waterstop plate 70, which is a heavy object, can be easily assembled using the erector 50. Here, the waterstop plate assembling attachment 53 is configured by adding the gripping member 53a to the piece guide attachment 52, but is not limited to this configuration and may also be configured to hold the waterstop plate 70 in a detachable manner. The waterstop plate assembling attachment 53 corresponds to the waterstop plate assembling portion of the present invention.

[0056] 3 and 5, waterstop plates 70 are installed as needed on the exposed surfaces of pieces 41-3, 41-6, 42-1, 42-2, and 42-6 exposed in space S. Waterstop plates 70 are made up of a first waterstop plate 71 that covers one exposed side surface of pieces 41-3 and 41-6 and extends in the front-to-rear direction (the direction of the central axis of the shield tunneling machine 100), and a second waterstop plate 72 that has a surface shaped like a divided ring and covers the exposed front surfaces of pieces 42-1, 42-2, and 42-6 and the area between the outer peripheral surfaces of pieces 41-3 and 41-6 and the inner peripheral surface of rear skin plate 12. Either or both of these two types of waterstop plates 71 and 72 may be installed depending on the waterstop conditions using a waterstopping agent or the like, but here we will explain the case where both waterstop plates 71 and 72 are installed.

[0057] Although not shown, through holes are formed in both side walls of each piece 41-3, 41-6, through which bolts connecting adjacent pieces are inserted. The first waterproof plate 71 is made of a rectangular steel flat plate that abuts against the exposed side walls of the remaining pieces 41-3, 41-6 over substantially the entire surface. The first waterproof plate 71 is fixed to the side walls 41-3, 41-6 of the remaining pieces by bolts that pass through through holes formed in the flat plate and through holes formed in the side walls. The first waterproof plate 71 also has notches formed to avoid the tail seals 61, 62.

[0058] The second water blocking plate 72 is in the form of a divided annular flat plate having a size equivalent to dividing the front surface of each of the pieces 42-1 to 42-6 into six portions so as to cover substantially the entire front surfaces of the exposed pieces 42-1, 42-2, 42-6.

[0059] Each through hole formed in the water stop plates 71, 72 is an elongated hole with its major axis extending in the radial direction of the shield, in order to ensure a large range for adjusting the position of the bolt.

[0060] Next, the worker sets up scaffolding (not shown) inside the shield tunneling machine 100 as needed, and uses this scaffolding to replace the tail seal 61. Specifically, the tail seal 61 to be replaced is cleaned and then removed. Then, after shaping the tail plate and skin plate as needed, a new tail seal 61 is installed.

[0061] Thereafter, the worker removes scaffolding or the like as necessary, removes the waterstop plate assembly attachment 53, and instead attaches the spacer placement attachment 54 to the erector 50 as shown in FIG.

[0062] Then, by operating this erector 50, spacers 81 and 82 are placed in the gaps between the pulled-out pieces 41-1 and 41-2 and the remaining pieces 42-1, 42-2, and 43-6 in the front-to-rear direction, as shown in Figures 6 and 7, to prevent buckling. The spacers 81 and 82 are made of steel and have a predetermined length. Here, the length of the spacer 81 placed in the space S after the top piece 41-1 has been pulled out is slightly longer than or the same as the length of the spacer 82 placed in the space S after the adjacent piece 41-2 has been pulled out.

[0063] The spacer arrangement attachment 54 is equipped with a holding member 54a that detachably holds the spacers 81, 82. The upper end wall of the holding member 54a can be fixed with bolts to seats that are fixed by welding to the inner sides of the spacers 81, 82. By holding the spacers 81, 82 with this holding member 54a, it becomes possible to position the spacers 81, 82, which are heavy objects, within the space S. The spacer arrangement attachment 54 corresponds to the spacer arrangement section of this invention.

[0064] Thereafter, by slightly extending the rods 15a-1 and 15a-2 of the propulsion jacks 15-1 and 15-2, the spacer 81 is sandwiched between the pieces 41-1 and 42-1 positioned in the fore-and-aft direction thereof, and the spacer 82 is sandwiched between the pieces 41-2 and 42-2 positioned in the fore-and-aft direction thereof, and the pieces 41-1 and 41-2 are maintained in the pulled-out state by the spacers 81 and 82.

[0065] Next, as shown in Figure 8, pieces 41-3 and 41-6, which are arranged adjacent to pieces 41-1 and 41-2 that are maintained in the pulled-out state, are pulled out. Piece 41-6, which is adjacent to the other side of top piece 41-1, has one side that is inclined to correspond to the side that contacts top piece 41-1. On the other hand, both sides of piece 41-3 are not inclined. These two pieces 41-3 and 41-6 are pulled out in the same way as the already explained pulling of pieces 41-1 and 41-2. It is possible to pull out one piece at a time or two at the same time.

[0066] The retraction stroke of rod 15a-6 when pulling out piece 41-6 adjacent to top piece 41-1 may be set to a rod length equal to or shorter than the length of rod 15a-1 corresponding to piece 41-1 in the pulled-out state. Also, the retraction stroke of rod 15a-3 when pulling out another piece 41-3 may be the same as, or slightly longer or shorter than, that of rod 15a-6.

[0067] Then, using the space S created by pulling out these two pieces 41-3 and 41-6, the tail seals 61-3 and 61-6 are replaced in the same manner as above, and spacers 83 and 86 are installed. The length of the spacers 83 and 86 may be set to correspond to the contraction stroke of the rods 15a-3 and 15a-6. The first watertight plate 71 is temporarily removed and installed on the exposed side walls of the remaining pieces 41-4 and 41-5.

[0068] Next, as shown in Figure 9, the remaining pieces 41-4 and 41-5 that make up the segment ring 31 located inside the tail seal 61 to be replaced are pulled out. Neither side surface of these pieces is inclined. The pulling out of these two pieces 41-4 and 41-5 is carried out in the same manner as the pulling out already explained. Note that they may be pulled out one by one or both at the same time.

[0069] The retraction stroke of the rods 15a-4 and 15a-5 when pulling out the remaining pieces 41-4 and 41-5 may be the same as the retraction stroke of the rod 15a-3 when pulling out the already pulled out piece 41-3 whose both side surfaces are not inclined.

[0070] Then, using the space S created by pulling out these two pieces 41-4, 41-5, the tail seals 61-4, 61-5 are replaced in the same manner as above, and spacers 84, 85 are installed. The first waterstop plate 71 is removed. Adjacent second waterstop plates 72 are connected at their ends.

[0071] Then, after applying a silicone seal or tail grease to the tail seal 61, the segment ring 31 is restored. This is done by slightly contracting the rods 15a of the propulsion jack 15 to remove the spacers 81 to 86, and then extending the rods 15a of the propulsion jack 15 to return the pieces 41-1 to 41-6 to their original positions. This process can be performed in the reverse order of the order in which they were pulled out, and finally the top piece 41-1 is returned to its original position. As described above, the both side surfaces of the piece 41-1 are inclined so that they taper forward, so by pushing them in, it is possible to reliably return the segment ring 31 to its original shape.

[0072] When returning pieces 41-1 to 41-6, it is preferable to apply a lubricant to both sides of the pieces. It is also preferable to embed new sealing material in both sides. This makes it possible to reduce damage to pieces 41-1 to 41-6 when returning them.

[0073] This completes the replacement of the tail seal 61, but backfilling agent is then injected through an injection port (not shown) to replace the waterproofing agent. After that, the process of constructing the segment ring can be carried out as usual.

[0074] The present invention is not limited to the above-described method for replacing the tail seal of a shield excavator, and can be modified as appropriate. For example, the present invention is not limited to the use of the above-described shield excavator 100, and various known shield excavators can be used.

[0075] In addition, in the segment ring 31 consisting of six pieces 41, the case where the pieces 41 are pulled out in three separate steps of two pieces 41 has been described. However, this is not limited to this, and the pieces 41 may be pulled out in six separate steps of one piece 41, or in two separate steps of three pieces 41. [Explanation of symbols]

[0076] 10...Skin plate (fuselage, excavator body), 11...Front skin plate, 12...Rear skin plate, 12a...Tail plate, 15 (15-1 to 15-6)...Propulsion jack, 15a (15a-1 to 15a-6)...Rod, 20...Excavation unit (excavator body), 21...Bulkhead, 22...Cutter head, 23...Drive unit, 30...Existing segment ring, 31 to 36...Segment ring, 41 (41-1 to 41-6), 42 to 45...Piece, 41a, 43a, 43b, 44a...Inlet, 50...Erector (assembly device), 51...Piece assembly attachment (piece assembly part), 51a...Support member, 52...Piece guide attachment (piece guide part), 52a...Guide member, 53...Waterstop plate assembly attachment (waterstop plate assembly portion), 53a...Gripping member, 54...Spacer placement attachment (spacer placement portion), 54a...Holding member, 61-63...Tail seal, 70...Waterstop plate, 71...First waterstop plate, 72...Second waterstop plate, 81-86...Spacer, 100...Shield tunneling machine, S...Space.

Claims

1. A method for replacing a tail seal that is provided at the rear of the trunk of the excavator body and seals between the inner peripheral surface of the trunk and the outer peripheral surface of the existing segment ring, in the course of constructing a tunnel by propelling the excavator body toward the tunnel face by extending the rods of multiple propulsion jacks, with existing segment rings consisting of pieces divided in the circumferential direction as reaction forces, and sequentially installing new segment rings on the tunnel face side of the existing segment rings, comprising: an assembly device having a piece assembly portion capable of detachably holding the pieces, and assembling the segment ring by holding the pieces; replacing the piece assembling section of the assembling device with a piece guide section capable of guiding the pieces; Then, while guiding the piece by the piece guide portion, the piece constituting the segment ring located inside the tail seal to be replaced is fixed to a spreader of the rod of the propulsion jack, and the rod is contracted to move the piece toward the face; A method for replacing a tail seal of a shield tunneling machine, characterized in that the tail seal to be replaced is replaced through the space created by the movement of the piece.

2. the piece guide portion of the assembly device is replaced with a waterstop assembly portion capable of guiding a first waterstop that covers the axially exposed surface of the piece exposed by the movement and the space between the outer peripheral surface of the segment ring and the inner peripheral surface of the skin plate of the excavator body, and a second waterstop that covers the space between the circumferentially exposed surface of the piece exposed by the movement and the outer peripheral surface of the segment ring, A method for replacing a tail seal of a shield excavator as described in claim 1, characterized in that the first waterstop and the second waterstop are then guided by a waterstop assembly section to assemble the first waterstop and the second waterstop.

3. The piece guide portion or the waterstop assembly portion of the assembly device is replaced with a spacer arrangement portion that detachably holds a spacer to be interposed between the moved piece and a piece located on the shaft side of the moved piece, A method for replacing the tail seal of a shield excavator as described in claim 2, characterized in that the spacer is then held by the spacer placement section and the spacer is installed between the moved piece and the piece located on the shaft side of the moved piece.

4. A shield excavator used in the method for replacing a tail seal according to any one of claims 1 to 3, In a shield tunneling machine, the excavator body is propelled toward the tunnel face by extending the rods of a plurality of propulsion jacks, which use existing segment rings consisting of pieces divided in the circumferential direction as reaction force receivers, and the segment rings are sequentially installed toward the tunnel face, thereby constructing a tunnel. a tail seal provided at the rear of a body of the excavator body and sealing between an inner circumferential surface of the body and an outer circumferential surface of the existing segment ring; an assembly device provided inside the excavator body and having a piece assembly part capable of detachably holding the pieces, A shield tunneling machine characterized in that the assembly device is capable of replacing the piece assembly section with a piece guide section capable of guiding the movement of the piece constituting the segment ring located inside the tail seal to be replaced toward the face side.

5. The shield tunneling machine described in claim 4, characterized in that the assembly device is capable of replacing the piece assembly section with a waterstop assembly section capable of guiding a waterstop covering the exposed surface of the piece and the inner surface of the skin plate.

6. A shield tunneling machine as described in claim 4 or 5, characterized in that the assembly device is capable of replacing the piece assembly section with a spacer arrangement section that can detachably hold spacers to be interposed between the pieces spaced apart in the direction from the face side toward the shaft side.

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