JP4599531B2 - Segment ring shape holding method and shape holding device - Google Patents

Description

  The present invention relates to a shape retaining method and a shape retaining device for a segment ring, and more particularly to a technique for retaining the shape of a segment ring formed by assembling segments into a ring shape in a tunnel excavated by a shield machine.

In the shield method that uses a shield machine to construct a tunnel in the ground, a plurality of segments are assembled in a ring shape in the tunnel behind the shield machine, and segment rings are constructed and connected in sequence, and the connected segment rings Is pushed by the extension of the shield jack to advance the shield machine.
However, when assembling the segment, deformation is likely to occur in the already constructed segment ring due to external earth pressure, its own weight, or pressing with a shield jack. There is a problem that it cannot be constructed properly.

  Thus, recently, various shape holding devices for holding the shape of the segment ring have been used. For example, an appropriate interval in the circumferential direction is provided at the position on the inner surface side and the rear side of the skin plate of the shield machine. A shape holding device having a configuration in which a plurality of shape holding members made of an expansion mat that can be moved back and forth or inflated / retracted toward the tunnel center side has been developed (see Patent Document 1).

According to the shape holding device, it is possible to satisfactorily hold the shape of the segment ring while ensuring a sufficient space in the shield machine.
JP 2003-83000 A

  By the way, in the shape holding device disclosed in Patent Document 1, the expansion mat is fixed to the inner surface of the skin plate of the shield machine, and when the rod of the shield jack extends to press the segment ring, the shape holding member A certain expansion mat moves forward with the skin plate and thus the shield machine while expanding, and moves while rubbing the outer peripheral surface of the segment.

  Thus, when the expansion mat moves while rubbing the outer peripheral surface of the segment, there is a problem that the expansion mat is easily worn and deteriorated due to friction or pulling. There is also a problem that when the rod of the shield jack is extended, the rod end of the shield jack hits the expansion mat and the expansion mat is easily damaged. These problems are particularly noticeable when the expansion mat is made of a soft elastic material such as a rubber member.

Therefore, as disclosed in part in Patent Document 1, it has been considered to protect the expansion mat from abrasion by covering the outer surface of the expansion mat with another member. It has been considered that a metal plate having high wear resistance is attached to a portion in contact with the segment.
In addition, it is considered that the expansion mat is contracted before the rod end of the extending shield jack contacts the expansion mat to avoid the contact between the rod end of the shield jack and the expansion mat in advance.

However, even if a metal plate is affixed to the outer surface of the expansion mat, the expansion mat is strongly pulled backward together with the metal plate due to friction generated between the metal plate and the segments, and the metal plate may be reversed and the expansion mat may be damaged. is there.
In addition, if the expansion mat is contracted before the shield jack contacts the segment, the shape of the segment ring is released and the shape of the segment ring is not retained. In this state, the segment ring is pressed with the rod of the shield jack. Then, there is a problem in that a component force in a radial direction other than the original axial direction acts on the segment ring, which may damage the segment itself or the connecting portion of the segment ring.

  The present invention has been made to solve such problems, and the purpose of the present invention is to prevent the shape-retaining member from being deteriorated or damaged and to reliably retain the shape of the segment ring. The object is to provide a holding method and a shape holding device.

  In order to achieve the above-mentioned object, the shape retaining method of the segment ring according to claim 1 is a segment ring for retaining the shape of the segment ring constructed by assembling a plurality of segments in a ring shape in the tunnel behind the shield machine. The shape holding method of the method of the present invention is to extend the shield jack rod, press the edge of the segment ring and advance the shield machine by receiving the reaction force of the segment ring. A first step of holding the shape of the segment ring by pressing the segment ring from the outer peripheral side under the reaction force of the skin plate by means of shape holding means slidably connected to a cylindrical skin plate extending from the frame When the rod of the shield jack is returned to the original position, the shape holding means Characterized in that comprising a second step of releasing the pressure from the outer peripheral side of the serial segment ring.

  The shape retaining method for a segment ring according to claim 2 is characterized in that, in claim 1, the shape retaining means comprises an inflatable body that can be expanded and contracted, and further includes expansion / contraction means for expanding and contracting the expansion body. In the step, the expansion body of the shape holding means is expanded by the expansion / contraction means, and in the second step, the expansion body of the shape holding means is not expanded by the expansion / contraction means.

In the shape retaining method of the segment ring according to claim 3, in claim 2, a plurality of inflating bodies of the shape retaining means are provided along the skin plate, and in the first step, the expansion / contraction means is the segment. The plurality of inflating bodies of the shape holding means are individually inflated according to the shape holding state of the ring.
In the shape retaining method of the segment ring according to claim 4, in the first step according to claim 1, the auxiliary shape retaining means further presses the segment ring from the outer peripheral side in response to the reaction force of the skin plate. The shape of the segment ring is maintained.

  In the shape retaining method of the segment ring according to claim 5, in claim 4, the shape retaining means and the auxiliary shape retaining means are formed of an inflatable / expandable expansion body, and expansion / contraction means for performing expansion / contraction of the expansion body. In the first step, the expansion body of the shape holding means is expanded by the expansion / contraction means, while the expansion body of the auxiliary shape holding means is not expanded, and in the second step, the expansion body is expanded by the expansion / contraction means. The expansion body of the shape holding means is not expanded while the expansion body of the auxiliary shape holding means is expanded.

  The shape retaining method for a segment ring according to claim 6 is the method of claim 5, wherein a plurality of inflatable bodies of the shape retaining means and the inflatable bodies of the auxiliary shape retaining means are provided along the skin plate. In the step, the expansion / contraction means individually expands the plurality of expansion bodies of the shape holding means according to the shape holding state of the segment ring, and in the second step, the expansion / contraction means expands the shape of the segment ring. The plurality of expansion bodies of the auxiliary shape holding means are individually inflated according to the holding state.

  The shape retaining device for a segment ring according to claim 7, wherein the shape retaining device for a segment ring that retains the shape of a segment ring constructed by assembling a plurality of segments in a ring shape in a tunnel behind a shield machine, A cylindrical skin plate extending toward the rear of the shield machine on the shield frame of the shield machine, and provided along the skin plate, is constructed on the inner peripheral side of the skin plate by extending the rod A shield jack that advances the shield machine by receiving a reaction force of the segment ring by pressing an edge of the segment ring, and is slidably connected to the skin plate at the rod tip of the shield jack And when pressing the edge of the segment ring with the shield jack, A shape holding means that is located between the kin plate and the segment ring and that receives the reaction force of the skin plate and presses the segment ring from the outer peripheral side to hold the shape of the segment ring. To do.

  The shape retaining device for a segment ring according to claim 8, wherein the shape retaining means comprises an inflatable body that can be expanded and contracted, and further includes expansion / contraction means for expanding and contracting the expansion body. The means expands the expansion body of the shape holding means when pressing the edge of the segment ring with the shield jack, and expands the expansion body of the shape holding means when the rod of the shield jack is returned to the original position. It is characterized by not letting it.

The shape retaining device for a segment ring according to claim 9, wherein a plurality of inflating bodies of the shape retaining means are provided along the skin plate, and the inflating / contracting means is in a shape retaining state of the segment ring. The plurality of inflating bodies of the shape holding means are individually inflated according to the above.
The shape retaining device for a segment ring according to claim 10, in claim 7, further, when the edge of the segment ring is pressed by the shield jack, the segment ring is not pressed and the rod of the shield jack is returned. In addition, there is provided auxiliary shape holding means for receiving the reaction force of the skin plate and pressing the segment ring from the outer peripheral side to hold the shape of the segment ring.

The shape retaining device for a segment ring according to claim 11, wherein the auxiliary shape retaining means is disposed at a position not interfering with the shape retaining means on the inner peripheral surface of the skin plate. And
In the shape retaining device for a segment ring according to claim 12, in claim 10, the shape retaining means is slidably connected to the rod end of the shield jack independently of the rod with respect to the skin plate, The auxiliary shape holding means shares the shape holding means.

  The shape retaining device for a segment ring according to claim 13 is the segment retaining device according to any one of claims 10 to 12, wherein the shape retaining means and the auxiliary shape retaining means are made of an inflatable and inflatable expanding body, and the expanding and contracting of the expanding body is performed. Expansion / contraction means for performing expansion, and the expansion / contraction means expands the expansion body of the shape holding means and presses the segment ring from the outer peripheral side when pressing the edge of the segment ring with the shield jack. The expansion body of the auxiliary shape holding means is not expanded, and when the rod of the shield jack is returned, the expansion body of the shape holding means is not expanded, while the expansion body of the auxiliary shape holding means is expanded and the segment ring is It is characterized by pressing from the side.

  The shape retaining device for a segment ring according to claim 14, wherein a plurality of inflatable bodies of the shape retaining means and an inflatable body of the auxiliary shape retaining means are provided along the skin plate. The means is configured to individually inflate each of the plurality of expansion bodies of the shape holding means according to the shape holding state of the segment ring, and to individually expand the plurality of expansion bodies of the auxiliary shape holding means. To do.

  In the segment ring shape holding device according to claim 15, in any one of claims 7 to 14, the shape holding means is slidably locked to a slide guide provided on the skin plate. Features.

  According to the shape retaining method of the segment ring of claim 1, when the segment ring is pressed with the shield jack and the shield machine is advanced, the shape is slidably connected to the skin plate at the rod tip of the shield jack. The segment ring is pressed from the outer peripheral side by the holding means to hold the shape of the segment ring (first step), and when returning the rod of the shield jack to the original position, the shape holding means presses from the outer peripheral side of the segment ring (Second step), the shape retaining means slides only on the skin plate having a relatively smooth surface without sliding on the segment ring whose surface tends to be relatively rough. In addition, while the segment ring is pressed with the shield jack, the segment by the shape retaining means is always used. When pressing from the outer periphery of the ring is maintained, a segment ring is constructed in the tunnel behind the shield machine and the segment ring is pressed with a shield jack to advance the shield machine. The shape of the segment ring can be reliably held while preventing the holding means from deteriorating. Thereby, it is possible to form a high-quality segment structure without any damage.

  According to the shape retaining method of the segment ring of claim 2, while the segment ring is being pressed by the shield jack, the expansion body of the shape retaining means is expanded by the expansion / contraction means (first step), and the rod of the shield jack is When returning to the original position, the expansion body of the shape holding means is not expanded by the expansion / contraction means (second step). Therefore, when the shape holding means is composed of a relatively soft expansion body, the expansion body The shape of the segment ring can be easily and reliably held by expanding and contracting the expansion body while preventing deterioration and breakage.

  According to the shape retaining method of the segment ring of claim 3, since the plurality of inflating bodies of the shape retaining means are individually expanded according to the shape retaining state of the segment ring (first step), particularly the segment ring. The shape of the segment ring can be easily pressed to strongly hold or restore the shape of the segment ring.

  According to the shape retaining method of the segment ring of claim 4, when the rod of the shield jack is returned to the original position, the segment ring is pressed from the outer peripheral side by the reaction force of the skin plate by the auxiliary shape retaining means. Since the shape of the segment ring is maintained (second step), not only while the segment ring is pressed with the shield jack but also when the segment ring is not pressed with the shield jack, for example, a new segment ring is constructed In this case, the pressure from the outer periphery side of the segment ring will be maintained, and the segment ring is built in the skin plate behind the shield machine and the segment ring is pressed with a shield jack to Segment ring while preventing the shape retaining means from deteriorating when moving forward It is possible to maintain the shape more reliably. Thereby, it is possible to form a higher-quality segment structure that is not damaged.

  According to the shape retaining method of the segment ring of claim 5, while the segment ring is pressed by the shield jack, the expansion body of the shape retaining means is expanded by the expansion / contraction means, while the expansion body of the auxiliary shape retaining means is expanded. When the rod of the shield jack is returned to the original position, the expansion body of the shape holding means is not expanded by the expansion / contraction means, while the expansion body of the auxiliary shape holding means is expanded (second process). As a result, when the shape holding means and the auxiliary shape holding means are constituted by a relatively soft expanding body, the shape of the segment ring can be easily formed by expanding and contracting the expanding body while preventing deterioration of the expanding body. Thus, it can be held more reliably.

  According to the shape retaining method of the segment ring of claim 6, the plurality of inflating bodies of the shape retaining means are individually inflated according to the shape retaining state of the segment ring (first step), and the shape retaining state of the segment ring is achieved. Accordingly, the plurality of expansion bodies of the auxiliary shape holding means are individually inflated (second step), so the shape of the part where the shape of the segment ring is difficult to hold or the part that is not sufficiently held is maintained. It can be strongly pressed not only by the means but also by the auxiliary shape holding means, so that the shape of the segment ring can be easily held and restored normally.

  According to the shape retaining device for the segment ring of claim 7, when the shape retaining means is connected to the rod end of the shield jack so as to be slidable with respect to the skin plate, and the segment ring is pressed by the shield jack, the shape retaining means Since the segment ring is pressed from the outer periphery side by the reaction force of the skin plate to hold the shape of the segment ring, the shape holding means slides against the segment ring whose surface tends to be relatively rough The surface slides only against the skin plate with a relatively smooth surface, and the pressing from the outer peripheral side of the segment ring is always maintained while the segment ring is pressed by the shield jack. , Construct a segment ring in the tunnel behind the shield machine and use the shield jack When you press the mentoring advancing the shield machine can reliably maintain the shape of the segment ring while preventing deterioration of the shape-retaining means. Thereby, it is possible to form a high-quality segment structure without any damage.

  According to the shape retaining device for the segment ring of claim 8, when the expansion body of the shape retaining means is expanded by the expansion / contraction means while the segment ring is being pressed by the shield jack, the rod of the shield jack is returned to the original position. Since the expansion body of the shape holding means is not expanded by the expansion / contraction means, when the shape holding means is configured by a relatively soft expansion body, the expansion body is prevented while preventing the expansion body from deteriorating. By expanding and contracting, the shape of the segment ring can be easily and reliably held.

  According to the shape retaining device for the segment ring of claim 9, since the plurality of inflating bodies of the shape retaining means are individually expanded according to the shape retaining state of the segment ring, the shape of the segment ring is particularly sufficient. The part that is difficult to be held or the part that is not sufficiently held can be strongly pressed to facilitate the shape of the segment ring so that it can be normally held or restored.

  According to the shape retaining device for the segment ring of claim 10, when returning the rod of the shield jack to the original position, the segment ring is pressed from the outer peripheral side by the reaction force of the skin plate by the auxiliary shape retaining means. Since the shape of the segment ring is maintained, the segment is not only pressed while the segment ring is pressed with the shield jack but also when the segment ring is not pressed with the shield jack, for example, when constructing a new segment ring. In the case where the pressure from the outer peripheral side of the ring is to be maintained, when the segment ring is constructed in the skin plate behind the shield machine and the segment ring is pressed with the shield jack to advance the shield machine, Change the shape of the segment ring while preventing the shape retaining means from deteriorating. It can be more reliably held. Thereby, it is possible to form a higher-quality segment structure that is not damaged.

  According to the shape retaining device for the segment ring of claim 11, when the rod of the shield jack is returned to the original position, the auxiliary shape retaining means provided at a position that does not interfere with the shape retaining means on the inner peripheral surface of the skin plate. Since the segment ring is pressed from the outer periphery side in response to the reaction force of the skin plate, the shape of the segment ring is maintained, so the segment ring is not only pressed while the segment ring is pressed with the shield jack, but also with the shield jack. While not being pressed, for example, when constructing a new segment ring, it is possible to maintain the pressure from the outer periphery side of the segment ring with a simple configuration, and press the segment ring with a shield jack to When moving forward, segment ring Can hold Jo more reliably.

  According to the shape retaining device for the segment ring of claim 12, the shape retaining means is slidably connected to the skin plate at the tip of the rod of the shield jack, and the auxiliary shape retaining means is the shape retaining member. Since the means is shared, the auxiliary shape holding means is used not only when the segment ring is pressed with the shield jack but also when the segment ring is not pressed with the shield jack, for example, when constructing a new segment ring. The shape holding means can be used as it is without being separately provided, and the pressure from the outer periphery side of the segment ring can be maintained, and when the segment ring is pressed with a shield jack and the shield machine is advanced, the shape holding means is deteriorated. While maintaining the shape of the segment ring efficiently and more reliably. Can.

Even if the shape holding means slides in conjunction with the rod of the shield jack, the segment ring can be pressed by the shield jack, so that the shape of the segment ring can be reliably held.
According to the shape retaining device for the segment ring of claim 13, while the segment ring is pressed by the shield jack, the expansion body of the shape retention means is expanded by the expansion / contraction means, while the expansion body of the auxiliary shape retention means is expanded. First, when returning the rod of the shield jack to the original position, the expansion body of the shape holding means is not expanded by the expansion / contraction means, while the expansion body of the auxiliary shape holding means is expanded. When the shape holding means is constituted by a relatively soft expanding body, the shape of the segment ring can be easily and more securely held by expanding and contracting the expanding body while preventing deterioration of the expanding body. it can.

  According to the shape retaining device for the segment ring of claim 14, according to the shape retaining state of the segment ring, the plurality of inflating bodies of the shape retaining means are individually inflated, and the plurality of inflating bodies of the auxiliary shape retaining means are respectively inflated. Since it is individually inflated, particularly the part where the shape of the segment ring is not sufficiently held or the part that is not sufficiently held can be strongly pressed not only by the shape holding means but also by the auxiliary shape holding means. It can be easily held and restored normally.

  According to the shape retaining device for a segment ring of claim 15, since the shape retaining means is slidably engaged with a sliding guide provided on the skin plate, the shape retaining means is a segment ring by the shape retaining means. Even when not pressed, it is well supported by the skin plate to prevent unnecessary deformation such as sagging, and when the segment ring is pressed by the shape holding means, it slides smoothly along the sliding guide with respect to the skin plate. Therefore, it is possible to more reliably prevent the shape holding means from deteriorating.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
First, the first embodiment will be described.
FIG. 1 is a rear longitudinal sectional view of a shield machine to which a shape retaining device for a segment ring according to a first embodiment of the present invention is applied (shaded lines indicating member cross sections are omitted, the same applies hereinafter), and FIG. 3 is a rear cross-sectional view of the shield machine along the line AA of FIG. 3, FIG. 3 is an enlarged view of the shape retaining device for the segment ring in the portion B of FIG. 1, and FIG. 4 is the shape retaining device for the segment ring in the portion C of FIG. The enlarged view of is shown.

The shield machine is, for example, a center shaft support type shield machine, and a description thereof is omitted here, but the front part of the shield machine, that is, the cutter unit, generally includes a cutter head, a center shaft, A motor, a screw conveyor, a bent jack, and the like are disposed.
The rear part of the shield machine connected to the cutter unit via a folding jack, that is, the tail unit 10 has a cylindrical skin plate 12 as the outer shell from the tail unit main body 11 at the rear of the shield machine (hereinafter simply referred to as the rear). And so on).

The tail unit 10 is provided with an erector device 20 for installing the segment 50 on the inner peripheral surface of the tunnel excavated by the shield machine so as to be included in the skin plate 12.
In the erector apparatus 20, a segment gripping device 22 that grips a segment 50 is supported by a suspension beam 24 so as to be movable in the radial direction, the suspension beam 24 is supported by a rotating body 26, and the rotating body 26 is connected to a tail unit via a roller 28. The main body 11 is configured to be rotatably supported in the circumferential direction.

Thus, as shown in FIG. 2, the erector apparatus 20 can assemble the arc-shaped segments 50 inside the skin plate 12 into a ring shape, and construct a segment ring 55 that is an element of the segment structure.
The segment rings 55 are connected to each other by using fasteners (bolts or the like), thereby forming a cylindrical segment structure.

Further, on the tail unit body 11 of the tail unit 10, a plurality of shield jacks 30 are arranged in the circumferential direction along the skin plate 12 according to the number of the segments 50 in the circumferential direction (here, for example, 6). It is installed.
The shield jack 30 is a hydraulic cylinder configured such that the rod 32 can be expanded and contracted by hydraulic pressure, and the end of the segment ring 55 constructed by the above-described erector device 20 is pressed by extending the rod 32, so that the segment ring 55 It is possible to advance the shield machine by receiving the reaction force.

An expander (shape holding means) 40 is connected to the tip of the rod 32 of each shield jack 30 together with the spreader shoe 33.
Specifically, the expansion body 40 is configured by bonding an expansion member 44 to one surface of the sliding plate 42, and an end portion of the sliding plate 42 is bonded to the spreader shoe 33 of the rod 32. Thereby, the expansion body 40 can slide along the skin plate 12 with the expansion and contraction operation of the rod 32.

5 shows a cross-sectional view of the expansion body 40, and FIG. 6 shows a vertical cross-sectional view of the expansion body 40. The expansion member 44 includes a tube member (for example, rubber tube) 44a and a cover member (for example, a rubber sheet). In detail, the tube member 44a is covered with a cover member 44b whose peripheral edge is fixed to the sliding plate 42 with a pin 45.
The tube member 44a has a fluid chamber inside, and the fluid chamber communicates with a fluid pressure supply unit (not shown) (expansion / contraction means) via a nozzle 46, and the fluid pressure supply unit communicates with the fluid chamber. It is configured to be freely expandable / contractable according to the supplied fluid pressure. Here, the fluid is, for example, air or oil. As a result, the entire expansion member 44 expands as shown by a two-dot chain line in FIGS.

On the other hand, as shown in FIGS. 3 and 4, on the inner peripheral surface of the skin plate 12, there are a plurality of guide grooves 13 that extend in the front-rear direction of the shield machine, that is, in the expansion / contraction direction of the rod 32 and accommodate the respective expansion bodies 40. A guide plate 14 is formed on both sides of the guide groove 13 so as to overhang the guide groove 13 (sliding guide).
Specifically, the guide plate 14 is fixed to the skin plate 12 using fasteners (embedded bolts or the like) so as to be flush with the inner peripheral surface of the skin plate 12, and the overhanged portion is on the side of each inflatable body 40. Engaging with the edge, each expansion body 40 is configured to be slidably locked in the guide groove 13 in the extending and contracting direction of the rod 32.

The depth of the guide groove 13 and the thickness of the guide plate 14 are determined so that the expansion body 40 is completely accommodated in the guide groove 13 and protrudes from the inner peripheral surface of the skin plate 12 when the expansion member 44 is contracted without being expanded. It is best to set it so that it does not.
Thereby, the expansion body 40 is guided by the guide groove 13 and the guide plate 14 and can be slid along the skin plate 12 within the expansion / contraction range of the rod 32, and the expansion of the expansion member 44 is contracted. It can be moved to a position.

  That is, the expansion body 40 moves to the position of the segment ring 55 constructed last when the rod 32 of the shield jack 30 is extended to press the end edge of the segment ring 55, and in this state, the expansion member 44 is the tube member. The fluid chamber 44a is supplied with fluid pressure from the fluid pressure supply unit, expands and contacts the segment ring 55, and receives the reaction force of the skin plate 12 to press the segment ring 55 from the outer peripheral side. .

At this time, the fluid pressure is evenly supplied to the expansion members 44 of all the expansion bodies 40, so that the segment rings 55 can be pressed by the expansion bodies 40 with an equal force over the entire circumference. It is possible to keep the shape in a perfect circle.
In addition, about the expansion | swelling body 40, you may make it arrange | position in the zigzag form mutually shifted in the front-back direction of a shield machine.

Hereinafter, the operation of the shape retaining device for the segment ring according to the first embodiment of the present invention configured as described above and the shape retaining method will be described.
FIG. 7 is a diagram showing the shape retaining procedure of the segment ring according to the first embodiment in time series, and will be described with reference to FIG. In the figure, only a part of the shape retaining device for the segment ring corresponding to the B part is shown, but the same applies to other parts not shown.

  As shown in the figure, when the assembly of the segment 50 is finished, the rod 32 of the shield jack 30 is extended for each piece of the segment 50, and the expanded body 40 in the contracted state is moved to the position of the segment 50. However, the spreader shoe 33 is brought into contact with the edge of the segment 50. This is performed over the entire circumference to construct the segment ring 55 (a).

  In this state, the inflating members 44 of all the inflating bodies 40 are inflated by supplying the fluid pressure evenly, and the inflating body 40 receives the reaction force of the skin plate 12 so that the segment ring 55 is evenly distributed from the outer peripheral side. Press with a strong force (b). Thus, by pressing the segment ring 55 constructed last with equal force from the outer peripheral side, the shape of the segment ring 55 constructed last is held in a perfect circle.

When the segment ring 55 is pressed from the outer peripheral side by the expansion body 40, the end of the segment ring 55 is pressed by the shield jack 30 while maintaining the shape of the segment ring 55 constructed last (c). Thereby, a shield machine advances and starts excavation (1st process).
At this time, since the segment ring 55 constructed last is held in a perfect circle by the expansion body 40, even if the segment ring 55 is pressed by the rod 32 of the shield jack 30, the segment ring 55 is not in the original axial direction. Thus, it is possible to prevent the segment 50 itself and the segment ring 55 from being damaged.

  When the shield machine starts digging, the skin plate 12 moves forward relative to the segment ring 55. At this time, since the expansion body 40 is connected to the tip of the rod 32 as described above, it does not slide at all with respect to the segment ring 55 even if the shield machine advances, and the skin plate 12 It slides only with respect to (d).

That is, when the shield machine presses the end of the segment ring 55 with the rod 32 of the shield jack 30, the expanded body maintains the shape of the segment ring 55 constructed last by the pressing force of the expanded body 40 in a perfect circle. It advances while sliding the skin plate 12 with respect to the 40 sliding plates 42.
In this way, when the expansion body 40 does not slide at all with respect to the segment ring 55 but only slides with respect to the skin plate 12, the surface of the segment ring 55 is relatively rough, so The sliding surface of the skin plate 12 is relatively easy to be worn and deteriorated, and the surface of the skin plate 12 is relatively smooth. The shape of the segment ring 55 can be easily and reliably held by the expansion body 40 during excavation while preventing the expansion body 40 from deteriorating.

  In particular, here, the expansion body 40 is provided with the sliding plate 42 and the guide groove 13 and the guide plate 14 for guiding the sliding plate 42, and the sliding plate 42 is skinned along the guide groove 13 and the guide plate 14. Since it is made to slide with the plate 12, the expansion body 40 can be slid sufficiently smoothly with respect to the skin plate 12, and the expansion | swelling which expanded without removing the unnecessary force which acts on the expansion body 40 is possible. The posture of the body 40 can be maintained well, and the expansion body 40 can be reliably prevented from deteriorating.

When the rod 32 of the shield jack 30 is extended to the limit position and the pressing of the segment ring 55 by the shield jack 30 is finished, the fluid pressure is released from the expansion member 44 and the expansion body 40 is contracted without being expanded (e).
When the expansion body 40 is contracted, the expansion body 40 is returned to the original position together with the rod 32 of the shield jack 30 (f) (second step).

  At this time, since the expansion body 40 is contracted, there is no friction between the expansion body 40 and the segment ring 55, and the deterioration of the expansion body 40 is also prevented. Further, since the expansion body 40 is guided by the guide groove 13 and the guide plate 14 and returns while being supported by the guide plate 14, the expansion body 40 does not hang down, and unnecessary expansion of the expansion body 40 is performed. Is prevented.

Then, in a state where the expansion body 40 is contracted, the assembly of the segment 50 is newly started, and the new segment 50 is connected to the previously constructed segment ring 55 using a fastener (bolt or the like) (g) ).
Thereafter, the procedures (a) to (g) are repeated. Thereby, the shape of the segment ring 55 can be reliably held at the time of excavation while preventing the expansion body 40 from being deteriorated, and a high-quality segment structure without damage or the like can be formed.

Next, a second embodiment will be described.
In the second embodiment, instead of the expansion body 40 of the first embodiment, two expansion bodies, a parent expansion body (shape holding means) 60 and a child expansion body (auxiliary shape holding means) 70, are used. Description of parts common to the first embodiment will be omitted, and only parts different from the first embodiment will be described.

FIG. 8 is a view corresponding to FIG. 3 showing an enlarged view of the shape retaining device for a segment ring according to the second embodiment of the present invention, and FIG. 9 is a view seen from the direction of arrow D in FIG. The following description is based on these drawings.
In the second embodiment, each spreader shoe 33 is connected to a parent inflating body 60 including a sliding plate 62 and an inflating member 64, similarly to the inflating body 40. The parent expansion body 60 is set to be shorter than the expansion body 40 when viewed in the direction of expansion and contraction of the rod 32 because the child expansion body 70 is provided behind.

Also in the second embodiment, the guide groove 13 and the guide plate 14 are provided on the inner peripheral surface of the skin plate 12 corresponding to each parent expansion body 60 as described above. The skin plate 12 can be slid along the guide groove 13 and the guide plate 14 in accordance with the expansion and contraction operation of the rod 32.
In the second embodiment, a child expansion body 70 is provided behind the parent expansion body 60 in the guide groove 13 so as not to interfere with the parent expansion body 60.

The child expansion body 70 includes a fixed plate 72 and an expansion member 74, and is configured to be freely expandable and contractable like the parent expansion body 60. However, unlike the parent expansion body 60, the child expansion body 70 is fastened to the skin plate 12 with a fastener (bolt or the like). It is fixed by.
Specifically, the child expansion body 70 is fixed to the skin plate 12 so as to face the rear end portion of the segment ring 55 constructed last when the rod 32 of the shield jack 30 is extended to the limit position. ing.

In the second embodiment as well, the parent inflatable body 60 may be alternately arranged adjacent to each other in the front-rear direction of the shield machine in a staggered manner.
Hereinafter, the operation of the shape retaining device for a segment ring according to the second embodiment of the present invention configured as described above and the shape retaining method will be described.
FIG. 10 is a diagram showing the shape retaining procedure of the segment ring according to the second embodiment in time series, and will be described with reference to FIG. In the same figure, only a part of the shape retaining device for the segment ring is shown as above, but the same applies to other parts not shown.

In the second embodiment, as shown in the figure, while the segment 50 is assembled and a new segment ring 55 is constructed, all the child expansion bodies 70 are expanded, and the child expansion body 70 moves forward one by one. The constructed segment ring 55 is pressed with an equal force from the outer peripheral side under the reaction force of the skin plate 12.
In this way, while the new segment ring 55 is being constructed, the previous segment ring 55 is held in a perfect circle, and the newly constructed segment ring 55 is also attached to the child expansion body 70. And can be constructed to be a perfect circle easily.

  Then, when the assembly of the new segment 50 is completed, the rod 32 of the shield jack 30 is extended for each piece of the segment 50, and the parent expansion body 60 in the contracted state is moved to the position of the segment 50. The spreader shoe 33 is brought into contact with the edge of the segment 50. This is performed over the entire circumference to construct a new segment ring 55 (a).

  In this state, the expansion members 64 of all the parent expansion bodies 60 are expanded by supplying fluid pressure evenly, and the segment rings 55 are subjected to the reaction force of the skin plate 12 by the parent expansion body 60 and the outer peripheral side. The child expansion body 70 is contracted without being expanded (b). Thus, by pressing the segment ring 55 constructed last with equal force from the outer peripheral side, the shape of the segment ring 55 constructed last is held in a perfect circle.

When the segment ring 55 is pressed from the outer peripheral side by the parent expansion body 60, pressing of the edge of the segment ring 55 by the rod 32 of the shield jack 30 is started in a state where the shape of the segment ring 55 constructed last is maintained (c) ). Thereby, a shield machine advances and starts excavation (1st process).
At this time, since the shape of the last constructed segment ring 55 is maintained by the parent inflating body 60, it is possible to reliably prevent the segment 50 itself and the connecting portion of the segment ring 55 from being damaged.

  When the shield machine starts digging, the skin plate 12 moves forward relative to the segment ring 55. At this time, since the parent expansion body 60 is connected to the tip of the rod 32 as described above, even if the shield machine advances, it does not slide at all with respect to the segment ring 55, and the skin plate 12 (D).

In other words, when the shield machine presses the edge of the segment ring 55 with the rod 32 of the shield jack 30, the shape of the segment ring 55 constructed last by the pressing force of the parent expansion body 60 is maintained in a perfect circle. On the other hand, the skin plate 12 moves forward with respect to the sliding plate 62 of the parent expansion body 60.
Thus, as described above, the shape of the segment ring 55 can be easily and reliably held by the parent expander 60 during digging while preventing the parent expander 60 from being deteriorated.

Particularly, since the sliding plate 62 is provided in the parent expansion body 60 and the guide groove 13 and the guide plate 14 for guiding the sliding plate 62 are provided, the deterioration of the parent expansion body 60 is reliably prevented as described above. can do.
Note that while the rod 32 of the shield jack 30 presses the edge of the segment ring 55 and the shield machine advances, the child expansion body 70 is in a contracted state. On the other hand, even if it moves relatively forward, there is no friction between the child expansion body 70 and the segment ring 55, and deterioration of the child expansion body 70 can also be prevented.

When the rod 32 of the shield jack 30 is extended to the limit position and the pressing of the segment ring 55 by the shield jack 30 is finished, the fluid pressure is released from the expansion member 64 and the parent expansion body 60 is contracted without expanding, while the child expansion is performed. The body 70 is expanded (e).
When the child expansion body 70 is expanded while the parent expansion body 60 is contracted, the parent expansion body 60 is returned to the original position together with the rod 32 of the shield jack 30 (f) (second step).

  At this time, since the parent expansion body 60 is contracted, friction does not occur between the parent expansion body 60 and the segment ring 55, and the deterioration of the parent expansion body 60 is also prevented. Further, since the parent expansion body 60 is guided by the guide groove 13 and the guide plate 14 and returns while being supported by the guide plate 14, the parent expansion body 60 does not hang down and the Unnecessary deformation is prevented.

Then, in a state where the parent expansion body 60 is contracted and the child expansion body 70 is expanded, the assembly of the segment 50 is newly started, and a new segment ring 55 is constructed (g). As a result, as described above, the newly constructed segment ring 55 can be constructed to be a perfect circle.
Thereafter, the procedures (a) to (g) are repeated. As a result, the shape of the segment ring 55 can be held more reliably during digging while preventing not only the deterioration of the parent expansion body 60 but also the child expansion body 70, and even higher quality without damage etc. A segment structure can be formed.

Next, a modification of the second embodiment will be described.
11 is a view corresponding to FIG. 4 showing an enlarged view of the shape retaining device for segment rings according to a modification of the second embodiment of the present invention, and FIG. 12 is a view seen from the direction of arrow E in FIG. Therefore, the description of the common parts with the first and second embodiments will be omitted, and only the parts different from the first and second embodiments will be described.

In the modification of the second embodiment, a child expansion body (auxiliary shape holding means) 80 is provided so as to be positioned between the expansion body (hereinafter referred to as parent expansion body) 40 and the adjacent parent expansion body 40. Yes.
Similar to the child expansion body 70, the child expansion body 80 includes a fixed plate 82 and an expansion member 84, and is accommodated in a groove 15 formed separately from the guide groove 13. 12 is fixed using a fastener (bolt or the like).

Specifically, the child expansion body 80 is placed on the skin plate 12 so as to be in parallel with the parent expansion body 40 when the rod 32 of the shield jack 30 presses the edge of the segment ring 55 and extends to the limit position. It is fixed.
In the modification of the second embodiment, the parent inflating body 40 may be alternately arranged adjacent to each other in the front-rear direction of the shield machine in a staggered manner.

As described above, even when the parent expansion body 40 and the child expansion body 80 are provided in parallel, the operation and the shape holding method are basically the same as those in the second embodiment. Here, the detailed description is omitted.
However, when the parent expansion body 40 and the child expansion body 80 are arranged in parallel as described above, as is apparent from a comparison between FIG. 9 and FIG. The segment ring 55 to be newly constructed can be pressed even better using the child expansion body 80.

Thus, the shape of the segment ring 55 can be held more reliably during excavation while preventing not only the deterioration of the parent expansion body 40 but also the child expansion body 80.
Next, a third embodiment will be described.
FIG. 13 is a view corresponding to FIG. 3 showing an enlarged view of the shape retaining device for a segment ring according to the third embodiment of the present invention, and FIG. 14 is a view seen from the direction of arrow F in FIG. Hereinafter, the description of the common parts with the first embodiment will be omitted, and only the parts different from the first embodiment will be described.

  In the third embodiment, each end of a pair of fluid cylinders 90, 90 extending along the rod 132 is connected to and supported by the spreader shoe 133 provided at the tip of the rod 132 of each shield jack 130. The fluid cylinder 90 includes a rod 92, and the rod 92 can be expanded and contracted by fluid pressure. Here, the fluid is, for example, air or oil. Although the fluid cylinder 90 is held by the spreader shoe 133 here, it may be held by a ring garter.

The end of the expansion body (shape holding means, auxiliary shape holding means) 140 on the shield jack 130 side is connected to the tip end portion 94 of the rod 92 of the fluid cylinder 90. In addition, although the expansion body 140 consists of the sliding plate 142 and the expansion member 144, the structure is the same as that of the said expansion body 40, and abbreviate | omits description here.
In other words, in the segment ring shape maintaining device according to the third embodiment, the rod 92 of the fluid cylinder 90 is expanded and contracted, so that the expansion body 140 is guided to the guide groove 13 and the guide independently of the operation of the rod 132 of the shield jack 130. It can be actuated along the plate 14.

Hereinafter, an operation of the shape retaining device for a segment ring according to the third embodiment of the present invention configured as described above and a shape retaining method will be described.
FIG. 15 is a diagram showing the shape retaining procedure of the segment ring according to the third embodiment in time series, and will be described with reference to FIG. In the same figure, only a part of the shape retaining device for the segment ring is shown as above, but the same applies to other parts not shown. Here, the description of the parts common to the first embodiment is omitted as appropriate.

  In the third embodiment, as will be described later, in the state where the assembly of the segment 50 is completed and the segment ring 55 has been constructed, the rod 132 of the shield jack 130 is moved in the state where the rod 92 of the fluid cylinder 90 is returned. The shoe 133 is brought into contact with the end edge of the segment 50, and the expansion body 140 is not expanded but is contracted while being moved to the position of the segment 50 (a).

In this state, the inflating members 144 of all of the inflating bodies 140 are inflated by supplying the fluid pressure evenly, and the inflating bodies 140 receive the reaction force of the skin plate 12 to cause the segment rings 55 to have an equal force from the outer peripheral side. (B), and starts pressing the edge of the segment ring 55 by the shield jack 130 (c) (first step).
When the rod 132 of the shield jack 130 is extended to the limit position and the pressing of the segment ring 55 by the shield jack 130 is finished (d), the rod 132 is returned to the original position while feeding the rod 92 of the fluid cylinder 90 (e) ( Second step).

That is, the expansion member 144 is expanded so that only the rod 132 of the shield jack 130 is returned while the segment ring 55 is pressed from the outer peripheral side by the expansion body 140.
Then, in this state, the assembly of the segment 50 is newly started, and the new segment 50 is connected to the segment ring 55 constructed immediately before by using a fastener (bolt or the like) (f).

When the assembly of the new segment 50 is completed, for each piece of the segment 50, the rod 132 of the corresponding shield jack 130 is extended while the rod 92 of the fluid cylinder 90 is accommodated, and the spreader shoe 133 is attached to the edge of the segment 50. The contact state is assumed. This is performed over the entire circumference to construct the segment ring 55 (g).
In this way, while the new segment ring 55 is being constructed, the previous segment ring 55 is held in a perfect circle by the pressure of the expansion body 140, and as described above, the child expansion body The segment ring 55 newly constructed by using the inflatable body 140 as it is without using 70 and 80 can also be constructed to be a perfect circle.

When the construction of the new segment ring 55 is completed, the fluid pressure is released from the expansion member 144 to contract the expansion body 140 so that the rod 92 of the fluid cylinder 90 is returned (h).
Thereafter, the procedures (a) to (h) are repeated. As a result, the shape of the segment ring 55 can be efficiently and more reliably held during excavation while preventing the expansion body 140 from deteriorating, and a higher quality segment structure without damage or the like can be formed. .

Although the description of the embodiment according to the present invention is finished above, the embodiment is not limited to the above, and various modifications can be made without departing from the spirit of the invention.
For example, in the above embodiment, the sliding plates 42, 62, 142 of the expansion bodies 40, 60, 140 are directly slid with the skin plate 12. However, for example, as shown in FIG. Alternatively, a plurality of rollers 45 may be embedded in the sliding plates 42, 62, 142, and the sliding plates 42, 62, 142 may be slid with the skin plate 12 via the rollers 45.

If the roller 45 is interposed in this way, the expansion body 40 can be slid more smoothly with respect to the skin plate 12, and the deterioration of the expansion body 40 can be further reliably prevented. .
Moreover, in the said embodiment, although it is made to supply a fluid pressure equally to the expansion members 44, 64, 144 of all the expansion bodies 40, 62, 140, all the expansion members 44, 64, 144 are not necessarily equal. However, the fluid pressure may be arbitrarily varied for each of the expansion members 44, 64, and 144 in accordance with the shape holding state of the segment ring 55 and the like. Thereby, it is possible to hold or restore the perfect circle normally by strongly pressing a portion where the shape of the segment ring 55 is not easily held in the perfect circle or a portion not held in the perfect circle.

In the above embodiment, the shape of the segment ring 55 is held in a perfect circle so as to form a cylindrical segment structure. However, the shape of the segment ring to be held is not limited to a perfect circle, Various settings may be made according to the shape of the tunnel.
Moreover, in the said embodiment, although the sliding plates 42, 62, and 140 were provided in the expansion bodies 40, 60, and 140, these do not need to provide in particular, and even if it does in this way, the effect of this invention is enough. Can get to.

In the above embodiment, the guide groove 13 and the guide plate 14 are provided. However, the guide groove 13 and the guide plate 14 are not necessarily provided, and even in this case, the effects of the present invention can be sufficiently obtained. Can do.
In the third embodiment, the fluid cylinder 90 is provided, and the rod 92 of the fluid cylinder 90 is expanded and contracted to operate the expansion body 140 independently of the operation of the rod 132 of the shield jack 130. However, it is not limited to the use of the fluid cylinder 90 as long as the expansion body 140 can be operated independently of the operation of the rod 132. For example, the spreader shoe 133 is used. And the expansion body 140 may be connected by a wire so that the wire is fed out and wound up. Alternatively, the spreader shoe 133 and the expansion body 140 are connected by a spring, and the expansion body 140 is contracted when the expansion body 140 contracts. May be automatically returned by the force of the spring.

It is a rear longitudinal cross-sectional view of the shield machine which the shape retention apparatus of the segment ring which concerns on 1st Example of this invention is applied. It is a rear cross-sectional view of the shield machine along the line AA in FIG. It is an enlarged view of the shape retaining apparatus of the segment ring in the B section of FIG. FIG. 3 is an enlarged view of a segment ring shape holding device in a portion C of FIG. 2. It is a cross-sectional view of an expansion body. It is a longitudinal cross-sectional view of an expansion body. It is a figure which shows the shape maintenance procedure of the segment ring which concerns on 1st Example in time series. It is a figure which shows the enlarged view of the shape retention apparatus of the segment ring which concerns on 2nd Example of this invention. It is the figure seen from the arrow D direction of FIG. It is a figure which shows the shape maintenance procedure of the segment ring which concerns on 2nd Example in time series. It is a figure which shows the enlarged view of the shape retention apparatus of the segment ring which concerns on the modification of 2nd Example of this invention. It is the figure seen from the arrow E direction of FIG. It is a figure which shows the enlarged view of the shape holding | maintenance apparatus of the segment ring which concerns on 3rd Example of this invention. It is the figure seen from the arrow F direction of FIG. It is a figure which shows the shape maintenance procedure of the segment ring which concerns on 3rd Example in time series. It is a figure which shows the state which embedded the some roller in the sliding plate.

Explanation of symbols

10 Tail unit 12 Skin plate 13 Guide groove (sliding guide)
14 Guide plate (sliding guide)
30, 130 Shield jack 32, 132 Rod 33, 133 Spreader shoe 40 Expansion body (shape holding means)
42, 62, 142 Sliding plate 44, 64, 144 Expansion member 45 Roller 50 Segment 55 Segment ring 60 Parent expansion body (shape holding means)
70, 80 child expansion body (auxiliary shape holding means)
90 Fluid cylinder 140 Expansion body (shape holding means, auxiliary shape holding means)

Claims (15)

A segment ring shape retaining method for retaining the shape of a segment ring constructed by assembling a plurality of segments into a ring shape in a tunnel behind a shield machine,
A cylindrical skin plate that extends from a shield frame to the rod tip of the shield jack when the shield jack rod is extended to push the edge of the segment ring and receive the reaction force of the segment ring to advance the shield machine A first step of holding the shape of the segment ring by pressing the segment ring from the outer peripheral side under the reaction force of the skin plate by means of shape holding means slidably connected to
When returning the rod of the shield jack to the original position, the second step of releasing the pressure from the outer peripheral side of the segment ring by the shape holding means;
A method for maintaining the shape of a segment ring, comprising: The shape holding means is made of an inflatable / expandable inflatable body, and further includes inflating / contracting means for inflating / contracting the inflatable body,
In the first step, the expansion body of the shape holding means is expanded by the expansion / contraction means,
2. The segment ring shape retaining method according to claim 1, wherein, in the second step, the expansion body of the shape retaining means is not expanded by the expansion / contraction means. A plurality of inflatable bodies of the shape retaining means are provided along the skin plate;
3. The segment ring according to claim 2, wherein in the first step, the expansion / contraction means individually inflates the plurality of expansion bodies of the shape holding means according to a shape holding state of the segment ring. Shape retention method.   In the second step, the shape of the segment ring is further retained by pressing the segment ring from the outer peripheral side under the reaction force of the skin plate by an auxiliary shape retaining means. Method for retaining the shape of segment rings. The shape holding means and the auxiliary shape holding means are made of an inflatable / expandable expansion body, and further include expansion / contraction means for expanding / contracting the expansion body,
In the first step, the expansion body of the shape holding means is expanded by the expansion / contraction means, while the expansion body of the auxiliary shape holding means is not expanded,
5. The shape retaining method for a segment ring according to claim 4, wherein, in the second step, the expansion body of the auxiliary shape holding means is expanded while the expansion body of the shape holding means is not expanded by the expansion / contraction means. . A plurality of inflatable bodies of the shape retaining means and the inflatable bodies of the auxiliary shape retaining means are provided along the skin plate, respectively.
In the first step, the expansion / contraction means individually expands the plurality of expansion bodies of the shape holding means according to the shape holding state of the segment ring,
6. The segment ring according to claim 5, wherein in the second step, the expansion / contraction means individually expands the plurality of expansion bodies of the auxiliary shape holding means according to the shape holding state of the segment ring. Shape retention method. A segment ring shape holding device for holding the shape of a segment ring constructed by assembling a plurality of segments into a ring shape in a tunnel behind a shield machine,
A cylindrical skin plate extending toward the rear of the shield machine on the shield frame of the shield machine;
Advancing the shield machine by receiving the reaction force of the segment ring by pressing the edge of the segment ring that is provided along the skin plate and extends the rod to press the edge of the skin plate With a shield jack
The rod end of the shield jack is slidably coupled to the skin plate, and when the edge of the segment ring is pressed by the shield jack, it is located between the skin plate and the segment ring, Shape holding means for receiving the reaction force of the skin plate and pressing the segment ring from the outer peripheral side to hold the shape of the segment ring;
A shape retaining device for a segment ring, comprising: The shape holding means is made of an inflatable / expandable inflatable body, and further includes inflating / contracting means for inflating / contracting the inflatable body,
The expansion / contraction means expands the expansion body of the shape holding means when the edge of the segment ring is pressed by the shield jack, and expands the shape holding means when the rod of the shield jack is returned to the original position. The shape retaining device for a segment ring according to claim 7, wherein the body is not expanded. A plurality of inflatable bodies of the shape retaining means are provided along the skin plate;
9. The segment ring shape holding device according to claim 8, wherein the expansion / contraction means individually expands the plurality of expansion bodies of the shape holding means according to the shape holding state of the segment ring.   Further, when the edge of the segment ring is pressed by the shield jack, the segment ring is not pressed, and when the rod of the shield jack is returned, it receives the reaction force of the skin plate and moves the segment ring to the outer peripheral side. The shape retaining device for a segment ring according to claim 7, further comprising auxiliary shape retaining means that presses the shape of the segment ring to retain the shape of the segment ring.   11. The segment ring shape holding device according to claim 10, wherein the auxiliary shape holding means is disposed at a position not interfering with the shape holding means on the inner peripheral surface of the skin plate. The shape holding means is slidably connected to the rod end of the shield jack independently of the rod with respect to the skin plate,
11. The segment ring shape holding device according to claim 10, wherein the auxiliary shape holding means shares the shape holding means. The shape holding means and the auxiliary shape holding means are made of an inflatable / expandable expansion body, and further include expansion / contraction means for expanding / contracting the expansion body,
The expansion / contraction means expands the expansion body of the shape holding means and presses the segment ring from the outer peripheral side when pressing the edge of the segment ring with the shield jack, while the expansion body of the auxiliary shape holding means When the rod of the shield jack is returned, the expansion body of the shape holding means is not expanded while the expansion body of the auxiliary shape holding means is expanded to press the segment ring from the outer peripheral side. The shape retaining device for a segment ring according to any one of claims 10 to 12. A plurality of inflatable bodies of the shape retaining means and the inflatable bodies of the auxiliary shape retaining means are provided along the skin plate, respectively.
The expansion / contraction means expands the plurality of expansion bodies of the shape holding means individually and expands the plurality of expansion bodies of the auxiliary shape holding means individually according to the shape holding state of the segment ring. The shape retaining device for a segment ring according to claim 13.   The shape retaining device for a segment ring according to any one of claims 7 to 14, wherein the shape retaining means is slidably engaged with a sliding guide provided on the skin plate.

Images