Method for replacing tail seal of shield excavator and water stop plate

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: A tail seal 61, which is disposed on a rear part of a skin plate 10 of an excavator body and seals between an outer peripheral surface of the skin plate 10 and an inner peripheral surface of an existing segment, is replaced during construction of the tunnel. Pieces constituting a segment ring 31 located in the inside of the tail seal 61 to be replaced are fixed to a spreader of a rod of a shield jack and moved forward by contracting the rod. Exposed surfaces in an axial direction of the pieces exposed by the movement and a gap between an outer peripheral surface of the segment ring 31 and an inner peripheral surface of a rear skin plate, and a gap between an exposed surface in circumferential direction of the piece and the outer peripheral surface of the segment ring 31 are covered by a water sealing plate 70 and the tail seal 61 is replaced through a space generated by the movement.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] To construct tunnels, a shield tunneling machine is used, which excavates the ground with the front end of the tunneling machine body and assembles the segment rings at the rear of the tunneling machine body, repeating this process for each ring.The shield tunneling machine is equipped with a tail seal such as a tail brush to seal the gap between the inner peripheral surface at the rear of the tunneling machine body and the outer peripheral surface of the segment ring.

[0003] When constructing long-distance tunnels, there was a risk that the tail seal would deteriorate or become damaged, leading to problems such as malfunctions of the segment rings and abnormalities in the jack thrust. As a result, it became 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] JP 2003-184489 A 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 rod of the shield jack must be longer than the length of the tail seal ring. In this case, however, a problem occurs in that a tunnel with a small bending radius 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 waterstop that enable the construction of a tunnel with a small bending radius. [Means for solving the problem]

[0008] The method for replacing a tail seal of a shield excavator of the present invention is a method for replacing a tail seal that is provided at the rear of the body of the excavator body and seals between the inner surface of the body and the outer surface of the existing segment ring, in the course of constructing a tunnel by propelling the excavator body toward the face side by extending the rods of a plurality of propulsion jacks, with existing segment rings consisting of pieces divided circumferentially as reaction force receivers, and sequentially installing new segment rings on the face side of the existing segment rings. The method is characterized in that the piece that constitutes the segment ring located inside the tail seal to be replaced is fixed to a spreader of the rod of the propulsion jack, and moved toward the face side by contracting the rod, and the axial exposed surface of the piece exposed by the movement, the gap between the outer surface of the segment ring and the inner surface of the skin plate of the excavator body, and the circumferential exposed surface of the piece exposed by the movement, and the gap between the outer surface of the segment ring and the inner surface of the skin plate of the excavator body are covered with a water stop, and the tail seal is replaced through the space created by the movement.

[0009] According to the method for replacing a tail seal of a shield machine of the present invention, the piece located inside the tail seal to be replaced is moved toward the 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 contraction of the rod required for replacing the tail seal is sufficient as long as it is possible to form a space in which the tail seal can be replaced, and compared to the technology described in Patent Document 1 above, it is possible to suppress the stroke of the rod and construct a tunnel with a small bending radius.

[0010] Furthermore, the axially exposed surfaces of the pieces exposed due to the movement, the area between the outer peripheral surface of the segment ring and the inner peripheral surface of the skin plate, and the area between the circumferentially exposed surfaces of the pieces exposed due to the movement and the outer peripheral surface of the segment ring are covered with a waterstop, making it possible to prevent water leakage from these areas.

[0011] The waterstop of the present invention is a shield excavator that constructs a tunnel by propelling the excavator body toward the tunnel face by extending the rods of multiple thrust jacks, which use existing segment rings consisting of pieces divided circumferentially as a reaction force receiver, and sequentially installing the segment rings at the tunnel face, and is a waterstop used when replacing the tail seal of a shield excavator that is provided at the rear of the body of the excavator body and has a tail seal that seals the space between the inner surface of the body and the outer surface of the existing segment ring, and is characterized in that it covers the axial exposed surface of the piece that is exposed when the piece constituting the segment ring located inside the tail seal to be replaced is moved toward the tunnel face, and the area between the outer surface of the segment ring and the inner surface of the skin plate of the excavator body, as well as the circumferential exposed surface of the piece that is exposed by the movement, and the area between the outer surface of the segment ring and the inner surface of the skin plate of the excavator body.

[0012] The waterstop of the present invention makes it possible to prevent water leakage from the axially exposed surface of the piece exposed due to movement and between the outer surface of the segment ring and the inner surface of the skin plate, as well as from the circumferentially exposed surface of the piece exposed due to movement and between the outer surface of the segment ring and the inner surface of the skin plate of the excavator body.

[0013] In the waterstop of the present invention, it is preferable that the waterstop includes a first waterstop that covers the area between the circumferentially exposed surface of the piece exposed by the movement and the outer peripheral surface of the segment ring.

[0014] In this case, it is possible to suppress water leakage from the portion covered by the first waterstop.

[0015] In addition, in the waterstop of the present invention, it is preferable that the waterstop includes a second waterstop covering the axially exposed surface of the piece and the area between the outer peripheral surface of the segment ring and the inner peripheral surface of the skin plate.

[0016] In this case, it is possible to prevent water leakage from the portion covered by the second waterstop. [Brief description of the drawings]

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

[0018] 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.

[0019] As shown in Fig. 1, the shield drilling 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 drilling machine body of the present invention, and the skin plate 10 corresponds to the body of the present invention.

[0020] 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 bending 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 bending jacks 14 can be used to adjust the direction of the front skin plate 12, i.e., the excavation direction of the shield machine 100.

[0021] A plurality of propulsion jacks (shield jacks) 15 for advancing the shield tunneling machine 100 with the existing segment ring 30 as a reaction force receiver are attached to the rear skin plate 12 at circumferential intervals.

[0022] Inside the rear skin plate 12, referring also to FIG. 2, an erector 50 for assembling a ring-shaped segment ring 31 or the like with pieces 41 or the like on the inner wall surface of the excavated tunnel is arranged.

[0023] The main body of the tunneling machine is advanced by a 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. A plurality of segment rings 31 or the like are, here, those in which six steel pieces 41 or the like are connected in the circumferential direction and are short substantially circular tubular shapes.

[0024] Pieces 41 or the like are carried into the shield tunneling machine 100, and the pieces 41 or the like are assembled into a ring shape using the erector 50 arranged in the shield tunneling machine 100. Since the pieces 41 or the like are heavy objects, the assembling work is performed in the shield tunneling machine 100 using the erector 50 provided with a piece assembling attachment 51 capable of assembling the pieces 41 or the like.

[0025] Although not shown in detail, each piece 41 or the like is formed with a held portion such as a recess or a through hole so as to be held by a protruding body such as a pin provided on the curved support member 51a of the piece assembling attachment 51. Each piece 41 or the like is held by the piece assembling attachment 51 by being placed on the support member 51a in a state where the held portion is held by the protruding body.

[0026] The excavation unit 20 has a partition wall 21 and a cutter head 22 that excavates the face in front of (the face side) the front end of the skin plate 10. The cutter head 22 is supported by the partition wall 21.

[0027] On the back surface of the partition wall 21, a drive unit 23 for rotationally driving the cutter head 22 is provided. The drive unit 23 is composed of a drive motor, a speed reducer, gears, etc. Due to the driving force of the drive unit 23, the cutter head 22 is rotationally driven at high torque via the drive shaft 24.

[0028] The space between the partition wall 21 and the cutter head 22 forms a compartment 25. The compartment 25 is for filling the excavated soil and mud together to counteract the earth pressure from the face. On the rear side of the partition wall 21, a soil and sand discharging device 26 communicating with the compartment 25 is provided. The soil and sand discharging device 26 composed of a mud supply pipe 26a and a mud discharge pipe 26b reaches the rear starting shaft.

[0029] At the rear part of the rear skin plate 12, tail seals 61 - 63 for sealing the gap between the outer peripheral surface of the existing segment ring 30 are attached. Note that the tail seals 61 - 63 include brush - shaped tail brushes.

[0030] Each of the tail seals 61 - 63 is annular as a whole and is provided so that its inner circumference contacts the outer peripheral surface of the segment ring 30. When the face side is taken as the front and the shaft side is taken as the rear, the tail seals 61 - 63 are provided in a plurality of stages, here three stages, spaced apart in the front - rear direction. Although not shown in detail, each of the tail seals 61 - 63 is fixed, for example, to a tail plate 12a divided in the circumferential direction for each stage by bolts, etc., and each tail plate 12a is fixed to the rear skin plate 12 by welding, bolts, etc. Thus, each of the tail seals 61 - 63 is replaceable with respect to the tail plate.

[0031] When replacing the tail seals 61 and 62 during tunnel construction, as shown in Fig. 2, the pieces 41 etc. that make up the segment ring 31 etc. are arranged so as to be in predetermined positions with respect to the tail seals 61 and 62 to be replaced. In other words, in a tunnel under construction where predetermined pieces 41 etc. are arranged in predetermined positions, the tail seals 61 and 62 at the predetermined positions can be replaced. Note that Figs. 2 and 3 are schematic development views seen from the central axis side of the shield tunneling machine 100.

[0032] Here, the case of replacing the tail seal 61 of the most face-side stage will be described. When constructing a curve etc., the clearance between the inner peripheral surface of the rear skin plate 12 and the segment ring 31 becomes narrow, so this tail seal 61 is likely to rub against the segment ring 31 and wear, and has the highest replacement frequency. The tail seal 62 may be replaced simultaneously with the tail seal 61. When replacing the tail seal 63, the shaft side needs to be separately sealed.

[0033] Each piece 41 that makes up the segment ring 31 located inside (on the central axis side of the shield tunneling machine 100) of the tail seal 61 to be replaced is a steel piece, and one injection port 41a for injecting a waterstop agent is formed. However, it is not always necessary for these pieces 41 to have the injection port 41a formed therein.

[0034] And each piece 43, 44 that makes up the segment rings 33, 34 located on the shaft side by a predetermined number of stages more than the segment ring 31 located inside the tail seal 61 to be replaced is also a steel piece, and a plurality of injection ports 43a, 43b, 44a are formed spaced apart in the circumferential direction. Here, each piece 43 that makes up the segment ring 33 located two stages on the shaft side from the segment ring 31 is provided with a plurality of injection ports 43a for injecting a consolidation lubricant and injection ports 43b for injecting a waterstop agent, respectively, spaced apart in the circumferential direction.

[0035] This segment ring 33 is located on the shaft side of the tail seal 63 which is located closest to the shaft side. Note that each piece 44 that constitutes the segment ring 34 which is one segment ring on the shaft side of this segment ring 33, that is, which is located three segment rings on the shaft side from the shaft side of the segment ring where the tail seal 61 to be replaced is located, is also provided with a plurality of injection ports 44a for water stop agents spaced apart in the circumferential direction.

[0036] Each of the injection ports 41a, 43a, 43b, 44a is provided with a check valve (not shown in detail) and is normally sealed with a plug. When injecting the consolidation lubricant or the water stop agent, the plug is removed, and after injection, the injection ports 41a, 43a, 43b, 44a are sealed with the plug.

[0037] Although not shown, all pieces are provided with at least one injection port for injecting a backfill agent into the gap between the ground and the segment ring 30. On the other hand, in the pieces 41 to 44 described above, not only is the backfill agent injected, but it is also necessary to stop the water in the gap between the segment rings 32 to 34 and the ground on the shaft side of the tail seal 63. Since this water stop needs to be performed reliably over the entire circumference, a plurality of injection ports 43a, 43b, 44a are provided spaced apart in the circumferential direction. Note that since the injection port 41a is provided for injecting the water stop agent in an emergency, only one injection port 41a is provided for each piece 41.

[0038] The number of injection ports 43a provided in each piece 43 that constitutes the segment ring 33 which is two segment rings on the shaft side of the segment ring 31 located inside the tail seal 61 to be replaced is preferably more or the same as the number of injection ports 41a, 44a provided in the other pieces 41, 44. Thereby, it becomes possible to reliably stop the water between the segment ring 33, which requires the most water stop and where there are no tail seals 61 to 63 on the shaft side thereof, and the ground.

[0039] Hereinafter, a method for replacing the 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.

[0040] First, as shown in FIG. 2, the positional relationship between the segment rings 31 to 34 with respect to the tail seal 61 to be replaced is set to the predetermined one 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.

[0041] Then, a consolidation lubricant is injected from each injection port 43a of the piece 43 that constitutes the segment ring 33 located on the shaft side of the tail seal 63 located closest to the shaft side, and then a waterstop agent is injected from the injection port 43b. Thereby, the flow of groundwater from the shaft side of the tail seal 63 can be stopped. Since the backfill agent cannot be injected when the waterstop agent is injected, the collapse of the ground is once prevented with the consolidation lubricant which is a low-strength filler, and then the waterstop agent is injected and replaced with the consolidation lubricant. Finally, the backfill agent is injected.

[0042] Next, as shown in FIG. 3, a part of the piece 41 that constitutes the segment ring 31 located inside the tail seal 61 to be replaced is pulled out toward the face side. Here, the case where the piece 41-1 located at the top of the segment ring 31 and the piece 41-2 adjacent to this are first pulled out will be described.

[0043] Note that it is preferable to apply a lubricant in advance to both circumferential side surfaces of these pieces 41-1 and 41-2 that are in contact with the adjacent pieces. Further, it is preferable to embed a sealing material in both of these side surfaces. By these, it becomes possible to reduce the damage that occurs during pulling out between the pieces 41-1 and 41-2.

[0044] At this time, the operator removes the piece assembly attachment 51 and instead attaches the piece guide attachment 52 to the erector 50 as shown in FIG. 4. Then, the operator operates this erector 50 to pull out the pieces 41-1 and 41-2 to secure the space S. This space S is a space that contains the space where the pieces 41-1 and 41-2 originally existed. The piece guide attachment 52 includes a trough-shaped guide member 52a that guides these pieces 41-1 and 41-2 on the guide surface. Since these pieces 41-1 and 41-2 are guided so as to be pressed against the upper surface of this guide member 52a, it is possible to prevent the remaining pieces 42-1, 42-2, 42-6, etc. from falling off. When guiding the pieces 41-1 and 41-2 located at the upper part, it is supported by the guide member 52a, and when guiding the pieces 41-3 to 41-6 located in the middle part and the lower part, it is preferably configured to be slidable along the guide member 52a.

[0045] While suppressing the remaining pieces 41-3 to 41-6 from falling off with the propulsion jacks 15-3 to 15-6, first pull out the piece 41-1 located at the top and the piece 41-2 on one side adjacent to this. The piece 41-1 located at the top has both side surfaces inclined so as to spread in a tapered shape toward the face side. And the piece 41-2 adjacent to these has one side surface inclined corresponding to the side surface in contact with the piece 41-1.

[0046] For the pulling out, first, fix the piece 41-1 at the top and the spreader provided at the end of the rear end of the rod 15a-1 of the propulsion jack 15-1 corresponding to this. Also, fix the piece 41-2 adjacent to the piece 41-1 at the top and the spreader provided at the end of the rod 15a-2 of the propulsion jack 15-2 corresponding to this. The fixing of the piece 41-1, etc. and the spreader provided at the end of the rod 15a-1, etc. may be fixed by known detachable fixing means such as a clamp or a vise.

[0047] After that, the rod 15a-1 of the propulsion jack 15-1 is contracted. As a result, the top piece 41-1 is pulled out. And simultaneously with or after this, the rod 15a-2 of the propulsion jack 15-2 is contracted. As a result, the piece 41-2 is pulled out.

[0048] The contraction strokes of the rods 15a-1 and 15a-2 in these extractions shall be a distance longer than the lengths of the spacers 81 and 82 described later. However, the contraction stroke when pulling out the top piece 41-1 shall be a distance slightly longer than the contraction stroke when pulling out the piece 41-2 so that a gap is created between the piece 41-2 when pulled out.

[0049] In addition, after replacing the tail seal 61, when the seal portion of the tail seal 61 passes through the segment ring 31 and water leaks out from the joints between the pieces 41 constituting the segment ring 31 due to damage to the tail seal 61 or the like, water leakage can be emergently prevented by injecting a waterstop agent from each injection port 41a of the piece 41.

[0050] Next, the operator removes the piece guide attachment 52 and instead attaches the waterstop plate assembly attachment 53 to the erector 50 as shown in FIG. 5. Then, the operator operates this erector 50 to install the waterstop plate 70 as described below.

[0051] The waterstop plate assembly attachment 53 is provided with a gripping member 53a capable of gripping the waterstop plate 70. By gripping the waterstop plate 70 with this gripping member 53a, the heavy waterstop plate 70 can be easily assembled by the erector 50. Here, the waterstop plate assembly attachment 53 has a configuration in which the gripping member 53a is added to the piece guide attachment 52, but it is not limited to such a configuration and may be something that detachably holds the waterstop plate 70.

[0052] Then, as shown in FIGS. 3 and 5, a water stop plate 70 is installed on the exposed surfaces of the pieces 41-3, 41-6, 42-1, 42-2, and 42-6 exposed in the space S as required. The water stop plate 70 includes a first water stop plate 71 that covers one exposed side surface of the pieces 41-3 and 41-6 and extends in the front-rear direction (the central axis direction of the shield tunneling machine 100), and a second water stop plate 72 that covers the exposed front surfaces of the pieces 42-1, 42-2, and 42-6 and has a shape in which an annular shape is divided to cover the space between the outer peripheral surface of the pieces 41-3 and 41-6 and the inner peripheral surface of the rear skin plate 12. These two types of water stop plates 71 and 72 may be installed either singly or both, depending on the water stop situation using a water stop agent or the like. Here, the case where both water stop plates 71 and 72 are installed will be described.

[0053] Through holes through which bolts for connecting adjacent pieces are inserted are formed in both side walls of each of the pieces 41-3 and 41-6, although not shown in the drawings. The first water stop plate 71 is composed of a rectangular steel flat plate that abuts against the exposed side walls of the remaining pieces 41-3 and 41-6 over substantially the entire surface. Then, it is fixed to the side walls 41-3 and 41-6 of the remaining pieces by bolts inserted through the through holes formed in this flat plate and the through holes formed in the side walls. Further, notches are formed in the first water stop plate 71 so as to replace the tail seals 61 and 62.

[0054] The second water stop plate 72 has a divided annular flat plate shape that is divided into six parts on the front surfaces of the pieces 42-1 to 42-6 so as to cover the front surfaces of the exposed pieces 42-1, 42-2, and 42-6 over substantially the entire surface.

[0055] In addition, each through hole formed in these water stop plates 71 and 72 is an elongated hole having the radial direction of the shield as the major axis in order to ensure a large adjustment width for the position of the bolts.

[0056] Next, the operator installs a scaffold (not shown) etc. inside the shield tunneling machine 100 as necessary, and uses this scaffold etc. to replace the tail seal 61. Specifically, after cleaning the tail seal 61 to be replaced, it is removed. Then, after shaping the tail plate and skin plate as necessary, a new tail seal 61 is attached.

[0057] After that, the operator removes the water stop plate assembly attachment 53 after removing the scaffold etc. as necessary, and instead, as shown in FIG. 6, attaches a spacer arrangement attachment 54 to the erector 50.

[0058] Then, by operating this erector 50, as shown in FIGS. 6 and 7, spacers 81 and 82 are respectively arranged in the front - rear gaps of the pulled - out pieces 41 - 1, 41 - 2 and the remaining pieces 42 - 1, 42 - 2, 43 - 6 to prevent back buckling. The spacers 81 and 82 are made of steel and have a predetermined length. Here, the length of the spacer 81 arranged in the space S where the top piece 41 - 1 is pulled out is slightly longer or the same as the length of the spacer 82 arranged in the space S where the adjacent piece 41 - 2 is pulled out.

[0059] The spacer arrangement attachment 54 includes a holding member 54a that detachably holds the spacers 81 and 82. The upper end wall of the holding member 54a can be fixed to a seat fixed by welding to the inner sides of the spacers 81 and 82 with bolts. By holding the spacers 81 and 82 with this holding member 54a, it becomes possible to position the heavy spacers 81 and 82 within the space S.

[0060] After that, by slightly extending the rods 15a - 1, 15a - 2 of the propulsion jacks 15 - 1, 15 - 2, the spacer 81 is clamped by the pieces 41 - 1, 42 - 1 located in its front - rear direction, and the spacer 82 is clamped by the pieces 41 - 2, 42 - 2 located in its front - rear direction, and the state where the pieces 41 - 1, 41 - 2 are pulled out is maintained by the spacers 81 and 82.

[0061] Next, as shown in FIG. 8, the pieces 41-3 and 41-6 arranged adjacent to the pieces 41-1 and 41-2 maintained in the pulled-out state are pulled out. The piece 41-6 adjacent to the other side of the top piece 41-1 has one side inclined corresponding to the side surface in contact with the top piece 41-1. On the other hand, both side surfaces of the piece 41-3 are not inclined. The pulling out of these two pieces 41-3 and 41-6 is performed in the same manner as the pulling out of the pieces 41-1 and 41-2 already described. Note that the pulling out may be performed one by one or two at the same time.

[0062] Note that the contraction stroke of the rod 15a-6 when pulling out the piece 41-6 adjacent to the top piece 41-1 may be set to the same length as or less than the length of the rod 15a-1 corresponding to the piece 41-1 in the pulled-out state. Also, the contraction stroke of the rod 15a-3 when pulling out the other piece 41-3 may be the same as, slightly larger than, or slightly smaller than this rod 15a-6.

[0063] Then, using the space S generated by pulling out these two pieces 41-3 and 41-6, in the same manner as above, the tail seals 61-3 and 61-6 are exchanged, and further, the spacers 83 and 86 are installed. The lengths of the spacers 83 and 86 may be set to lengths corresponding to the contraction strokes of the rods 15a-3 and 15a-6. Note that the first water stop plate 71 is removed once and installed on the exposed side walls of the remaining pieces 41-4 and 41-5.

[0064] Next, as shown in FIG. 9, the remaining pieces 41-4 and 41-5 constituting the segment ring 31 located inside the tail seal 61 to be exchanged are pulled out. Both side surfaces of these are not inclined. The pulling out of these two pieces 41-4 and 41-5 is performed in the same manner as the pulling out already described. Note that the pulling out may be performed one by one or two at the same time.

[0065] When pulling out the remaining pieces 41-4 and 41-5, the contraction stroke of the rods 15a-4 and 15a-5 may be the same as the contraction stroke of the rod 15a-3 when pulling out the piece 41-3 whose both side surfaces that have already been pulled out are not inclined.

[0066] Then, using the space S generated by pulling out these two pieces 41-4 and 41-5, the tail seals 61-4 and 61-5 are exchanged in the same manner as above, and further, spacers 84 and 85 are installed. Note that the first water stop plate 71 is removed. Also, both ends of adjacent second water stop plates 72 are connected to each other.

[0067] Then, after applying silicon seal or tail grease etc. 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 each piece 41-1 to 41-6 to its original position. This process may be performed in the reverse order of the pulling-out order, and finally the top piece 41-1 is returned to its original position. As described above, since the both side surfaces of the piece 41-1 are inclined so as to spread in a tapered shape toward the front in combination, by pushing these in, it becomes possible to surely return the segment ring 31 to its original shape.

[0068] Note that when returning the pieces 41-1 to 41-6, it is preferable to apply a lubricant to both side surfaces thereof. Also, it is preferable to embed a new sealing material in both side surfaces. By these means, it becomes possible to reduce the damage caused to the pieces 41-1 to 41-6 when returning them.

[0069] Thereby, the replacement work of the tail seal 61 is completed, but a backfill agent is injected from an injection port (not shown) and replaced with a water stop agent. After that, the process of constructing the segment ring may be performed in the same manner as usual.

[0070] The present invention is not limited to the method for replacing the tail seal of the shield tunneling machine described above, and can be appropriately changed. For example, it is not limited to using the shield tunneling machine 100 described above, and various known shield tunneling machines can be used.

[0071] In addition, in the segment ring 31 composed of six pieces 41, the case where the pieces 41 are pulled out in three times, two at a time, has been described. However, it is not limited to this. For example, the pieces 41 may be pulled out one by one in six times, or three by three in two times.

Explanation of reference numerals

[0072] 10... Skin plate (body, tunneling machine 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 (tunneling machine body), 21... Partition wall, 22... Cutter head, 23... Driving unit, 30... Existing segment ring, 31 to 36... Segment ring, 41(41-1 to 41-6), 42 to 45... Piece, 41a, 43a, 43b, 44a... Injection port, 50... Erector, 51... Piece assembly attachment, 51a... Support member, 52... Piece guide attachment, 52a... Guide member, 53... Water stop plate assembly attachment, 53a... Gripping member, 54... Spacer arrangement attachment, 54a... Holding member, 61 to 63... Tail seal, 70... Water stop plate, 71... First water stop plate, 72... Second water stop plate, 81 to 86... Spacer, 100... Shield tunneling machine, S... Space.

Claims

1. A method for replacing a tail seal provided at the rear of the body of an excavator main body and sealing between the inner peripheral surface of the body and the outer peripheral surface of an existing segment ring, while constructing a tunnel by advancing the excavator main body toward the face side by extending the rods of a plurality of propulsion jacks using the existing segment ring composed of pieces divided in the circumferential direction as a reaction force receiver, and sequentially installing new segment rings on the face side of the existing segment ring, the method comprising: fixing the pieces constituting the segment ring located inside the tail seal to be replaced to a spreader of the rod of the propulsion jack, and moving the rod toward the face side by contracting the rod; covering 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 main body, and the circumferentially 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 main body with a water stop plate; replacing the tail seal through the space generated by the movement. A method for replacing a tail seal of a shield excavator, characterized by the above.

2. A water stop plate used when replacing the tail seal of a shield excavator that constructs a tunnel by advancing the excavator main body toward the face side by extending the rods of a plurality of propulsion jacks using an existing segment ring composed of pieces divided in the circumferential direction as a reaction force receiver, and sequentially installing segment rings on the face side, the shield excavator being provided with a tail seal that seals between the inner peripheral surface of the body of the excavator main body and the outer peripheral surface of the existing segment ring, the water stop plate comprising: covering the axially exposed surface of the piece exposed when the piece constituting the segment ring located inside the tail seal to be replaced is moved toward the face side, and the space between the outer peripheral surface of the segment ring and the inner peripheral surface of the skin plate of the excavator main body, and the circumferentially 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 main body. A water stop plate characterized by the above.

3. The water stop plate according to claim 2, characterized in that it includes a first water stop plate that covers the circumferential 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 boring machine body.

4. The water stop plate according to claim 2 or 3, characterized in that it includes a second water stop plate that covers the axial 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 boring machine body.

Images