Method for replacing tail seal of shield tunneling machine and tunnel under construction

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 as a reaction receiver and a new segment ring is sequentially installed forward to construct a tunnel. A tail seal, which is disposed on a rear part of a skin plate of the excavator body and seals between an outer peripheral surface of the skin plate and an inner peripheral surface of the segment ring, is replaced during construction of the tunnel. A water sealing agent is injected from a plurality of inlets 43a disposed so as to be separated away in a circumferential direction on pieces 43 constituting a segment ring 33 behind the most backward tail seal, then, a piece 41 constituting a segment ring 31 is fixed to a spreader of a rod 15a of the shield jack 15. The piece 41 is pulled out forward by contracting the rod 15a and the tail seal is replaced through a space generated thereby.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for replacing a tail seal of a shield tunneling machine and a tunnel under construction.

Background Art

[0002] To construct a tunnel, a shield tunneling machine is used that repeats, for each ring, excavating the ground at the front end of the tunneling machine body and assembling a segment ring at the rear of the tunneling machine body. In a shield tunneling machine, a tail seal such as a tail brush is provided to prevent water leakage from the gap between the inner peripheral surface of the rear part of the body of the tunneling machine and the outer peripheral surface of the segment ring.

[0003] When constructing a long tunnel, the tail seal may deteriorate or be damaged, which may cause problems such as segment ring defects and abnormal jack thrust. Therefore, it has been necessary to replace the tail seal during tunnel excavation.

[0004] Therefore, Patent Document 1 discloses a technique in which, with a new tail seal ring fixed to the front end of the original tail seal ring, the rod of the shield jack is extended to move these tail seal rings backward, and then the rod is shortened to remove the original tail seal ring.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the technology described in Patent Document 1 above, the stroke of the rod of the shield jack must be longer than the length of the tail seal ring. However, in this case, there is a problem that a tunnel with a small bending radius cannot be constructed.

[0007] In view of the above points, an object of the present invention is to provide a method for replacing a tail seal of a shield tunneling machine and a tunnel under construction that can construct a tunnel with a small bending radius.

Means for Solving the Problems

[0008] The method for replacing the tail seal of a shield tunneling machine according to the present invention is to propel the tunneling machine 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 install new segment rings on the face side of the existing segment ring to construct a tunnel. During this process, a tail seal provided at the rear of the body of the tunneling machine body and sealing between the inner peripheral surface of the body and the outer peripheral surface of the existing segment ring is replaced. The method is characterized in that a water stop agent is injected from at least one injection port provided in each of the pieces constituting the segment ring located closer to the shaft side than the tail seal closest to the shaft side, and then the piece constituting the segment ring located inside the tail seal to be replaced is fixed to the spreader of the rod of at least one of the plurality of propulsion jacks, and the rod is contracted to pull out the piece toward the face side, and the tail seal to be replaced is replaced through the space generated by the pulling out of the piece.

[0009] According to the method for replacing the tail seal of the shield tunneling machine of the present invention, a piece located inside the tail seal to be replaced is pulled out toward the face by contracting the rod of the propulsion jack, and the tail seal is replaced through the space generated by this pulling. As a result, the amount of rod contraction required for replacing the tail seal only needs to be such that a space where the tail seal can be replaced can be formed. Compared with the technology described in Patent Document 1 above, it is possible to suppress the stroke of the rod, and a tunnel with a small bending radius can be constructed.

[0010] And, since the water stop agent is injected from at least one injection port provided in each piece constituting the segment ring located on the shaft side closer to the shaft than the tail seal on the shaft side, it is possible to prevent leakage from the shaft side that may occur due to pulling out the piece in order to replace the tail seal over the entire circumference.

[0011] In the method for replacing the tail seal of the shield tunneling machine of the present invention, while advancing the tunneling machine body, a low-strength filler is injected from the injection port instead of the backfill agent, and after stopping the tunneling machine body, the water stop agent is injected to replace the injected filler with the water stop agent, which is preferable.

[0012] In this case, while pulling out the piece on the face side, it is possible to stop the water on the shaft side closer to the shaft than the tail seal on the shaft side and suppress leakage.

[0013] Also, in the method for replacing the tail seal of the shield tunneling machine of the present invention, it is preferable that the piece to be pulled out toward the face side is preliminarily coated with a lubricant on the surface that contacts the piece adjacent in the circumferential direction.

[0014] In this case, it is possible to reduce the damage that occurs when pulling out the piece.

[0015] The tunnel under construction according to the present invention propels the tunneling machine 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 a new segment ring is sequentially installed on the face side of the existing segment ring. In the tunnel under construction, each piece constituting the segment ring located on the shaft side rather than the segment ring located inside the tail seal to be replaced is characterized by having at least one injection port.

[0016] According to the tunnel under construction of the present invention, since it is possible to inject a waterstop agent from at least one injection port provided in each piece constituting the segment ring located on the shaft side rather than the segment ring located inside the tail seal to be replaced, it is possible to prevent water leakage from the shaft side that may occur due to pulling out the piece in order to replace the tail seal over the entire circumference.

[0017] In the tunnel under construction of the present invention, each piece constituting the segment ring located on the shaft side rather than the segment located inside the tail seal to be replaced preferably has at least one injection port spaced apart in the circumferential direction.

[0018] In this case, even if water leakage occurs from the face side due to pulling out the piece in order to replace the tail seal, it is possible to urgently inject a waterstop agent from the injection port of the piece to suppress the water leakage.

[0019] Further, in the tunnel under construction of the present invention, each piece constituting the segment ring located inside the tail seal to be replaced preferably has a plurality of injection ports spaced apart in the circumferential direction.

[0020] In this case, by injecting a waterstop agent from the plurality of injection ports of the piece, it is possible to prevent water leakage from the location where the pulled-out piece originally existed, which may occur due to pulling out the piece in order to replace the tail seal.

[0021] Also, in the tunnel under construction of the present invention, it is preferable that lubricant is preliminarily applied to the surfaces of the segments located inside the tail seal to be exchanged and the segments of the segment ring located on the face side of the cutting face, which are in contact with the pieces adjacent in the circumferential direction.

[0022] In this case, it becomes possible to reduce the damage that occurs when the piece is pulled out.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0024] A shield tunneling machine 100 used when implementing a method for replacing a tail seal of a shield tunneling machine according to an embodiment of the present invention will be described with reference to the drawings.

[0025] As shown in FIG. 1, the shield tunneling machine 100 includes a skin plate (shield cylinder) 10 and an excavation 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 excavation unit 20 correspond to the excavation machine body of the present invention, and the skin plate 10 corresponds to the body of the present invention.

[0026] 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, and the front skin plate 11 can be bent in an arbitrary direction with respect to the rear skin plate 12. A plurality of middle folding jacks 14 that connect the front skin plate 11 and the rear skin plate 12 are provided at intervals in the circumferential direction, and the direction of the front skin plate 12, that is, the tunneling direction of the shield tunneling machine 100 can be adjusted by these middle folding jacks 14.

[0027] 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 intervals in the circumferential direction.

[0028] 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 to the inner wall surface of the excavated tunnel with pieces 41 or the like is arranged.

[0029] Using the existing segment ring 30 as a reaction force receiver, the main body of the tunneling machine is advanced by a propulsion jack, 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 rings 31, etc. are a plurality of, here six steel pieces 41, etc. connected in the circumferential direction, and are short and substantially circular tubular.

[0030] The pieces 41, etc. are carried into the shield tunneling machine 100, and the pieces 41, etc. are assembled into a ring shape using the erector 50 arranged in the shield tunneling machine 100. Since the pieces 41, etc. are heavy objects, the assembling work is carried out inside the shield tunneling machine 100 using the erector 50 equipped with a piece assembling attachment 51 capable of assembling the pieces 41, etc.

[0031] Although not shown in detail, each piece 41, etc. has a held portion such as a recess or a through hole in order 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, etc. 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.

[0032] The excavation unit 20 has a partition wall 21 and a cutter head 22 that excavates the face in front (face side) of the front end of the skin plate 10. The cutter head 22 is supported by the partition wall 21.

[0033] 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., and the cutter head 22 is rotationally driven at high torque via the drive shaft 24 by the driving force of the drive unit 23.

[0034] The space between the bulkhead 21 and the cutter head 22 forms a compartment 25. The compartment 25 is for filling the excavated earth and sand together with the muddy water to counteract the earth pressure from the face. On the rear side of the bulkhead 21, an earth and sand discharging device 26 communicating with the compartment 25 is provided. The earth and sand discharging device 26 consisting of a mud feeding pipe 26a and a mud discharging pipe 26b reaches the rear launching shaft.

[0035] 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 also include brush - shaped tail brushes.

[0036] 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. The tail seals 61 - 63 are provided in a plurality of stages, here three stages, spaced apart in the front - rear direction with the face side being the front and the shaft side being the rear. 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 or the like, and each tail plate 12a is fixed to the rear skin plate 12 by welding, bolts, or the like. Thus, each of the tail seals 61 - 63 is replaceable with respect to the tail plate.

[0037] When replacing the tail seals 61, 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 a predetermined position with respect to the tail seals 61, 62 to be replaced. In other words, in the tunnel under construction where the predetermined pieces 41, etc. are arranged in a predetermined position, the tail seals 61, 62 at the predetermined position 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.

[0038] Here, the case of replacing the tail seal 61 of the stage located closest to the face is described. When constructing a curve or the like, 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 out, 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.

[0039] Each piece 41 constituting 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 be formed with the injection port 41a.

[0040] Each piece 43, 44 constituting 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 at intervals in the circumferential direction. Here, each piece 43 constituting 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 consolidation lubricant and injection ports 43b for injecting waterstop agent, which are spaced apart in the circumferential direction.

[0041] This segment ring 33 is located on the shaft side of the tail seal 63 located closest to the shaft side. Note that each piece 44 constituting the segment ring 34, which is one stage on the shaft side from this segment ring 33, that is, here, the segment ring 34 located three stages on the shaft side from the segment ring on the shaft side of the segment ring 31 located inside the tail seal 61 to be replaced, is also provided with a plurality of injection ports 44a for injecting waterstop agent, which are spaced apart in the circumferential direction.

[0042] Each injection port 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.

[0043] Although not shown, all the pieces are provided with at least one injection port for injecting the backfill agent into the gap between the natural ground and the segment ring 30. On the other hand, in the above-described pieces 41 to 44, not only the backfill agent is injected, but it is also necessary to stop the water in the gap between the segment rings 32 to 34 and the natural ground on the shaft side from 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 at intervals 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.

[0044] The number of injection ports 43a provided in each piece 43 constituting the segment ring 33 located two shaft sides from the segment ring 31 located inside the tail seal 61 to be replaced is preferably larger than or the same as the number of injection ports 41a, 44a provided in the other pieces 41, 44. Thereby, it becomes possible to surely stop the water between the segment ring 33, which requires the most water stop and where no tail seals 61 to 63 exist on the shaft side from this, and the natural ground.

[0045] Hereinafter, a method for replacing the tail seal of the shield tunneling machine according to the embodiment of the present invention will be described using the above-described shield tunneling machine 100.

[0046] 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 above-described predetermined one. 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.

[0047] Then, from each injection port 43a of the piece 43 that constitutes the segment ring 33 located on the shaft side from the tail seal 63 located closest to the shaft side, a consolidation lubricant is injected, and then, a water stop 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 after the water stop agent is injected, the collapse of the ground is once prevented with the consolidation lubricant, which is a low-strength filler, and then the water stop agent is injected to replace the consolidation lubricant. Finally, the backfill agent is injected.

[0048] 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 it are first pulled out will be described.

[0049] It is preferable to apply a lubricant in advance to both circumferential side surfaces of these pieces 41-1 and 41-2 that come into contact with the adjacent pieces. Further, it is preferable to embed a sealing material in both of these side surfaces. By these measures, it becomes possible to reduce the damage that occurs during pulling out between the pieces 41-1 and 41-2.

[0050] 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 6 located in the middle part and the lower part, it is preferably configured to be slidable along the guide member 52a.

[0051] 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 it. The piece 41-1 located at the top has both side surfaces inclined so as to widen 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.

[0052] 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 it. 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 it. 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 vice.

[0053] 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.

[0054] 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 slightly longer distance 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.

[0055] In addition, after replacing the tail seal 61, when the sealed portion of the tail seal 61 passes through the segment ring 31 and 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 or the like, water leakage can be emergently prevented by injecting a waterstop agent from each injection port 41a of the piece 41.

[0056] 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.

[0057] 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.

[0058] 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 of installing both water stop plates 71 and 72 will be described.

[0059] On both side walls of each of the pieces 41-3 and 41-6, through holes through which bolts for connecting adjacent pieces are inserted are formed, although not shown. 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.

[0060] The second water stop plate 72 has a divided annular flat plate shape that divides the front surfaces of the pieces 42-1 to 42-6 into six parts so as to cover the front surfaces of the exposed pieces 42-1, 42-2, and 42-6 over substantially the entire surface.

[0061] Note that each through hole formed in these water stop plates 71 and 72 is an oblong 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.

[0062] 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.

[0063] After that, the operator removes the stop plate assembly attachment 53 after removing the scaffold etc. as necessary, and instead, as shown in FIG. 6, attaches the spacer arrangement attachment 54 to the erector 50.

[0064] 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.

[0065] The spacer arrangement attachment 54 includes a holding member 54a for detachably holding the spacers 81 and 82. The upper end wall of the holding member 54a can be fixed to a seat fixed by welding on the inner side of the spacers 81, 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 inside the space S.

[0066] 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.

[0067] 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 pieces may be pulled out one by one or two at a time.

[0068] In addition, 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 be the same 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.

[0069] 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 replaced, 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 temporarily removed and installed on the exposed side walls of the remaining pieces 41-4 and 41-5.

[0070] Next, as shown in FIG. 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. 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 pieces may be pulled out one by one or two at a time.

[0071] 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.

[0072] Then, by utilizing 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 furthermore, 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.

[0073] 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 jacks 15 to remove the spacers 81 to 86, and then extending the rods 15a of the propulsion jacks 15 to return each piece 41-1 to 41-6 to its original position. This process may be carried out 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 together, by pushing these in, it becomes possible to surely return the segment ring 31 to its original shape.

[0074] 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.

[0075] 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 carried out in the same manner as usual.

[0076] 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.

[0077] In addition, in the segment ring 31 composed of six pieces 41, the case where the pieces 41 are pulled out two by two in three times 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

[0078] 10... Skin plate (body, tunneling machine body), 11... Front skin plate, 12... Rear skin plate, 12a... Tail plate, 15(15-1~15-6)... Propulsion jack, 15a(15a-1~15a-6)... Rod, 20... Excavation unit (tunneling machine body), 21... Partition wall, 22... Cutter head, 23... Driving unit, 30... Existing segment ring, 31~36... Segment ring, 41(41-1~41-6), 42~45... Piece, 41a, 43a, 43b, 44a... Injection port, 50... Erector (assembly device), 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, 61~63... Tail seal, 70... Water stop plate, 71... First water stop plate, 72... Second water stop plate, 81~86... Spacer, 100... Shield tunneling machine, S... Space.

Claims

1. A method for replacing a tail seal that seals between the inner peripheral surface of the body of an excavation machine and the outer peripheral surface of an existing segment ring, which is fixedly provided to be replaceable at the rear part of the body of the excavation machine, during the construction of a tunnel by advancing the excavation machine body toward the face side by extending the rods of a plurality of propulsion jacks using the existing segment ring 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, comprising: injecting a water stop agent from at least one injection port provided in each of the pieces constituting the segment ring located on the shaft side of the tail seal closest to the shaft, to stop the water in the gap between the segment ring and the ground on the shaft side of the tail seal; then, fixing the piece constituting the segment ring located inside the tail seal to be replaced to the spreader of the rod of at least one of the plurality of propulsion jacks, and pulling out the piece toward the face side by contracting the rod; replacing the tail seal to be replaced, which is fixed to the rear part of the body of the excavation machine exposed in the space through the space generated by pulling out the piece. A method for replacing a tail seal of a shield excavation machine, characterized by the above.

2. The method for replacing a tail seal of a shield excavation machine according to claim 1, characterized in that while advancing the excavation machine body, a low-strength filler is injected from the injection port instead of the backfill agent, and after stopping the excavation machine body, the water stop agent is injected to replace the injected filler with the water stop agent.

3. The method for replacing a tail seal of a shield excavation machine according to claim 1 or 2, characterized in that a lubricant is previously applied to the surface of the piece to be pulled out toward the face side, which contacts the piece adjacent in the circumferential direction.

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