JP5142808B2 - Heterogeneous tunnel junction structure and method - Google Patents

Description

The present invention relates to a heterogeneous tunnel junction structure and method in which a wide segment ring having a wide tunnel width and a narrow segment ring having a narrow tunnel width are joined in the tunnel axis direction.

  When constructing a shield tunnel, when using a special construction method to reduce the amount of construction work at the junction or junction where there is an emergency parking zone on the way, in places where a structure is planned to be built later It is necessary to change the cross-sectional shape of the shield tunnel. As a shield construction method that changes the tunnel cross section without the need for a shaft construction or an auxiliary construction method from the ground, a construction method for partially expanding or reducing the tunnel cross section, a construction method for constructing a temporary partition inside the tunnel, and construction equipment have been proposed. ing.

  In particular, conventionally, for example, as shown in Patent Document 1, a tunnel cross-section changing direction that can reduce the cross-section of a shield mine to an arbitrary shape using an existing shield machine has been proposed.

In this construction method, first, as shown in FIG. 14A, the normal cross-section portion in the tunnel 95 is constructed using the shield machine 61. Then, after the construction of the normal section segment 91-n is finished, the excavation is stopped once. Next, as shown in FIG. 14B, the special segment 87 is installed in the normal cross-section segment 91- (n-1), and the reaction force receiver 85 is installed inside the normal cross-section segment 91-n. The reaction force receiver 85 and the special segment 87 have a shape and a configuration that can be transmitted to the normal cross-sectional segment 91. From the state shown in FIG. 14B, the shield jack 65 and the extension shield jack 73 are pressed against the normal cross-section segment 91-n and the reaction force receiver 85, respectively, and extended, while the natural ground 62 is excavated. The shield machine 61 is advanced. Next, as shown in FIG. 14 (c), the additional shield jack 73 is pressed against the new section segment 85-1, excavating the natural ground 62, and the shield machine 61 is sequentially advanced. As a result, it is possible to change a tunnel cross section in which a wide segment ring having a wide tunnel width and a narrow segment ring having a narrow tunnel width are joined in the tunnel axis direction.
JP 2004-169396 A

  By the way, in such a tunnel cross-section changing structure disclosed in Patent Document 1, as shown in FIG. 15, when pressed by the additional shield jack 73, a force flows in the direction indicated by the arrow in the figure. However, the shape of the special segment 87 is an isosceles triangle having a substantially right angle as shown in FIG. For this reason, the force from the additional shield jack 73 is bent sharply by about 45 ° in the special segment 87, and as a result, stress is concentrated on the special segment 87. As a result, the reaction force receiver 85 and the special segment 87 become unstable due to the pressing force of the extension shield jack 73, and greatly deformed as shown by the dotted line in the figure.

  Further, since the special segment 87 has a triangular cross section, there is a problem that the rigidity against the pressing force from the additional shield jack 73, that is, the deformation suppressing effect is small.

  Furthermore, in the technique disclosed in Patent Document 1, it takes a long time to construct the reaction force receiver 85 and the special segment 87, and it is difficult to shorten the construction period. Further, when the reaction force receiver 85 and the special segment 87 are installed, a separate heavy machine is required, which causes a problem that the construction cost increases and the construction period is further prolonged.

Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is to concentrate stress generated at the junction of the heterogeneous tunnel from the shield jack when joining the heterogeneous tunnel. Another object of the present invention is to provide a heterogeneous tunnel junction structure and method that can alleviate the above, secure rigidity (deformation suppressing effect) against jack thrust at the relevant location, and further simplify the construction process and shorten the construction period.

  In order to solve the above-described problems, the heterogeneous tunnel junction structure to which the present invention is applied has a wide segment ring having a wide tunnel width and a narrow segment ring having a narrow tunnel width, each having an overlapping portion in the tunnel axis direction. In the heterogeneous tunnel junction structure joined in the tunnel axis direction, one part of the wide segment ring is located inside the wide segment ring at a position corresponding to a non-overlapping part other than the overlapping part in the narrow segment ring. A composite segment ring structure in which a reinforcing segment ring in which segments are connected to each other is further formed is formed, and a tunnel cross section non-overlapping region of the cross section of the narrow segment ring and the wide segment ring at the tunnel junction is formed. The partition plate having a shape corresponding to the region is the reinforcing segment. It is interposed between the ring and the narrow segment ring, and is characterized in that is provided so as to close the region.

  The heterogeneous tunnel junction method to which the present invention is applied is based on a shield method, in which a wide segment ring having a wide tunnel width and a narrow segment ring having a narrow tunnel width are overlapped with each other in the tunnel axis direction. In the dissimilar tunnel junction method for joining, the wide segment ring is constructed on the end side of the wide tunnel when the tunnel width is shifted from the wide to the narrow, and the narrow segment ring inside the wide segment ring is Forming a composite segment ring structure in which a reinforcing segment ring is formed by connecting segments from one part of the wide segment ring to another part at a position corresponding to a non-overlapping part other than the overlapping part, and the wide segment Between the ring and the narrow segment ring to be joined The non-overlapping region of the tunnel cross section while bringing the surface of the partition plate having a shape corresponding to the non-overlapping region of the tunnel cross section between the reinforcing segment ring and the wide segment ring into contact with at least the end surface of the reinforcing segment ring Further, the narrow segment ring is sequentially constructed from the partition plate toward the tunnel axis direction.

  The heterogeneous tunnel junction method to which the present invention is applied is based on a shield method, in which a wide segment ring having a wide tunnel width and a narrow segment ring having a narrow tunnel width are overlapped with each other in the tunnel axis direction. In the heterogeneous tunnel junction method, the cross section of the narrow segment ring to be joined to the narrow segment ring when the narrow segment ring is sequentially constructed and the tunnel width is shifted from narrow to wide. A partition plate having a shape corresponding to a non-overlapping region of the tunnel cross section is provided on the narrow segment ring, the wide segment ring is constructed from the partition plate in the tunnel axis direction, and the narrow segment ring is disposed inside the wide segment ring. In the position corresponding to the non-overlapping part other than the above overlapping part in the width segment ring, A reinforcing segment ring in which segments are connected from one part of the segment ring to another part is formed into a composite segment ring structure constructed so that the partition plate is interposed between the narrow segment ring, Further, the wide segment ring is constructed sequentially.

  The double segment ring structure to which the present invention is applied has a wide segment ring having a wide tunnel width and an overlapping portion in the tunnel axis direction by connecting the segments from one part of the wide segment ring to another part. The reinforcing segment ring is constructed at a position corresponding to a portion other than the overlapping portion in the narrow-width segment ring to be connected.

  The heterogeneous tunnel junction method to which the present invention is applied has a composite segment ring structure. That is, a reinforcing segment ring made of segments is constructed inside the wide tunnel, particularly in the vicinity of the tunnel junction. For this reason, when constructing a wide tunnel or narrow tunnel, if a pressing force is applied to a segment using a shield jack, the stress flow can be made smooth and stress concentration can be reduced. It becomes possible.

  In addition, by constructing a reinforcing segment ring for a composite segment ring structure, especially over a plurality of rings, and then shifting the shield jack installation member, the jacking position is changed by changing the jack pressing position. As a result, it is possible to improve itself, and as a result, it is possible to improve the deformation suppressing effect.

  In particular, the heterogeneous tunnel junction method to which the present invention is applied has a composite segment ring structure constituted by reinforcing segment rings, and therefore can be constructed only with a shield machine without using a special heavy machine. For this reason, it is possible to shorten the construction period, and it is possible to reduce the construction cost.

  Hereinafter, as the best mode for carrying out the present invention, a heterogeneous tunnel junction structure in which a wide segment ring having a wide tunnel width and a narrow segment ring having a narrow tunnel width are joined in the tunnel axial direction will be described with reference to the drawings. This will be described in detail.

  For example, as shown in FIG. 1, a heterogeneous tunnel junction structure 1 to which the present invention is applied includes a wide tunnel 20 formed by joining wide segment rings 2 having a wide tunnel width in the axial direction, and a narrow width having a narrow tunnel width. It consists of a narrow tunnel 30 formed by joining segment rings 3 in the axial direction. The wide tunnel 20 and the narrow tunnel 30 are joined to each other at the tunnel junction 9.

  2 is a plan view of the heterogeneous tunnel junction structure 1 to which the present invention is applied. FIG. 3A is a cross-sectional view taken along line AA ′ in FIG. 2B is a cross-sectional view taken along the line BB ′ in FIG. 2 relating to the tunnel junction 9 between the wide tunnel 20 and the narrow tunnel 30, and FIG. 3C is a cross-sectional view taken along the line CC ′ in FIG. 3D is a cross-sectional view taken along the line DD ′ in FIG.

  Incidentally, the heterogeneous tunnel junction structure 1 to which the present invention is applied is applied to a case where the tunnel cross-section width must be changed, for example, when an emergency parking zone is provided in a road underground tunnel.

  The narrow-width tunnel 30 is a tunnel that constitutes a general traveling section, and the narrow-width segment ring 3 constituting the narrow-width tunnel 30 includes a plurality of segments 31 that are connected in the tunnel circumferential direction based on a shield method. The segments 31 are connected by bolts or the like via a joint (not shown) or the like as necessary in the tunnel circumferential direction or the tunnel axial direction. As shown in FIG. 3A, the narrow segment ring 3 is continuously connected from the segment 31_1 in the circumferential direction of the tunnel to the segment 31_7. The segment 31_1 is located between the segment 31_1 and the segment 31_7. 31_8 to 31_10 are connected so as to be bent inward. At this time, the segment 31_10 is bolted on the inner surface side to the segment 31_1, and the segment 31_7 is bolted on the inner surface side to the segment 31_8.

  In the present embodiment, the case where the segment ring 3 is composed of ten segments 31 will be described as an example, but the number of segments 31 is not limited to this. In addition, the segments 31_8 to 31_10 are not limited to the shape bent inward, and may have any cross-sectional shape.

  The wide tunnel 20 is a tunnel provided in parallel with an emergency parking zone together with a general traveling part, and the wide segment ring 2 constituting this is composed of a plurality of segments 21 connected in the circumferential direction of the tunnel based on a shield method. . This segment 21 is connected by a bolt or the like via a joint or the like (not shown) toward the tunnel circumferential direction or the tunnel axial direction. For example, when the wide segment ring 2 is configured by connecting ten segments 21 in the tunnel circumferential direction, as shown in FIG. 3C, the wide segment ring 2 is continuously connected in the tunnel circumferential direction as shown in FIG. Thus, the segment 21_10 is reached. Unlike the narrow segment ring 3, the wide segment ring 2 has a substantially circular cross section. The segments 21_1 to 21_7 in the wide segment ring 2 correspond to the segments 31_1 to 31_7 in the narrow segment ring 3, and are configured to have the same shape, size, and curvature. The segments 21_1 to 21_7 in the wide segment ring 2 and the segments 31_1 to 31_7 in the narrow segment ring 3 overlap each other in the tunnel axis direction. A portion that overlaps in the tunnel axis direction between the wide segment ring 2 and the narrow segment ring 3 is hereinafter referred to as an overlapping portion. On the other hand, in the narrow segment ring 3, portions (segments 31_8 to 31_10) other than the overlapping portions (segments 31_1 to 31_7) are referred to as non-overlapping portions.

  Therefore, the wide segment ring 2 is widened by the segments 21_8 to 21_10 as compared with the narrow segment ring 3 having the segments 31_8 to 31_10 bent inward.

  Further, the wide tunnel 20 is further provided with a reinforcing segment ring 35 ′ on the inner side. The reinforcing segment ring 35 ′ is configured by connecting segments from one part 37 to another part 38 inside the wide segment ring 2. In the example of FIG. 3C, the reinforcing segment ring 35 'is connected from the one portion 37 in the segment 21_1 to the other portion 38 in the segment 21_7. The reinforcing segment ring 35 ′ is composed of segments 35 </ b> _ <b> 1 to 35 </ b> _ <b> 3, and each corresponds to the segments 31 </ b> _ <b> 8 to 31 </ b> _ <b> 10 in the narrow-width segment ring 3. That is, the reinforcing segment ring 35 '(segments 35_1 to 35_3) is disposed at a position corresponding to a non-overlapping portion (segments 31_8 to 31_10) of the narrow-width segment ring 3.

  At this time, the segment 21_1 is bolted to the segment 31_1. The segment 21_7 is bolted to the segment 31_7.

  The reinforcing segment ring 35 ′ formed inside the wide tunnel 20 only needs to be configured with at least one ring toward the tunnel axial direction G. Incidentally, the reinforcing segment ring 35 'may be removed afterwards as will be described later, but the present invention assumes a structure before the reinforcing segment ring 35' is removed.

  3D is a cross-sectional view taken along the line D-D ′ of the wide tunnel 20, and is a cross-sectional view on the axial direction G side from the end portion 51 of the composite segment structure 39 shown in FIG. 2. In FIG. 3D, the reinforcing segment ring 35 ′ in FIG. 3C is omitted, and the segment 35_1 to 35_3 is not formed, and only the wide segment ring 2 is formed. 21_10 is continuously connected in the tunnel circumferential direction.

  These segments 21, 31 and 35 may be arranged in a staggered manner in some cases, but in such a case, the segment rings adjacent to each other in the axial direction are shifted by half a segment.

  As described above, when the wide segment ring 2 and the narrow segment ring 3 having different cross-sectional shapes are joined, the narrow segment ring 3 bent inward as shown in FIG. The segments 31_8 to 31_10 and the segments 21_8 to 21_10 in the wide segment ring 2 become the tunnel cross-section non-overlapping regions 41 that do not overlap each other. In the heterogeneous tunnel junction structure 1 to which the present invention is applied, a wall-like partition plate 42 is provided so as to block the tunnel cross-section non-overlapping region 41.

  The partition plate 42 is in contact with the segments 31_8 to 31_10 in the narrow segment ring 3 on one surface. Further, the segments 21_8 to 21_10 in the wide segment ring 2 are brought into contact with each other on the other surface. That is, the partition plate 42 has a flat surface where the segments 21 and 31 come into contact with both front and back surfaces. The partition plate 42 is made of steel or steel / concrete. The partition plate 42 may be configured as an integral type, or may be provided in combination with those divided in advance.

  As shown in FIG. 3B, such a partition plate 42 is attached so as to block the tunnel cross-section non-overlapping region 41, thereby opening the tunnel inside and outside the tunnel cross-section non-overlapping region 41. Can be closed.

  The water stop box 24 is disposed outside the narrow segment ring 3 so as to be in contact with the partition plate 42. The water stop box 24 has a box structure in which an outer wall with a tail brush 15 attached to a region in contact with the outer peripheral surface of the narrow segment ring 3 is formed of a steel plate, and the tail brush 15 contacts the segment 31 as shown in FIG. By arranging in this way, it becomes possible to prevent underground moisture from entering the tunnel via the partition plate 42.

  The backfill material 25 is used for the purpose of suppressing the collapse of the ground excavation region, and is made of, for example, a cement-based material, and corresponds to the tunnel cross-section non-overlapping region 41 outside the narrow segment ring 3. Filled in area.

  Next, a heterogeneous tunnel junction method to which the present invention is applied will be described in detail with reference to the drawings.

  This dissimilar tunnel joining method joins a tunnel 30 with a narrow tunnel width to a wide tunnel 20 with a wide tunnel width when excavating a tunnel based on a shield method. As shown in FIG. 4A, the shield machine 44 used for tunnel excavation is fixed to a cylindrical skin plate 45, a shield jack installation member 46, a shield jack 47, and an end surface of the skin plate 45. The face plate 48 is provided. The shield jack 47 has an end attached to the shield jack installation member 46, and is configured to be extendable and contractible in the tunnel axial direction.

  First, the wide tunnel 20 having a wide tunnel width is constructed based on the shield method. At this time, the shield machine 44 is used to excavate the natural ground 49 and repeat the operation of installing the segment 21 along the inner circumference of the excavated mine.

  Next, as shown in FIG. 4B, the construction of the composite segment ring structure 39 is started inside the wide tunnel 20. The segments 21 constituting the outer periphery are similarly joined using the shield machine 44. In addition to this, the segments 35 constituting the composite segment ring structure 39 are similarly constructed. The segments 35 constituting the composite segment ring structure 39 need to be connected to at least one ring toward the axial direction G, but are preferably connected over a plurality of rings.

  Next, after the construction of the composite segment ring structure 39 is completed, a wall-like partition plate 42 is formed as shown in FIG. 4C, and a tunnel cross-section non-overlapping region 41 formed between the segments 35 and 21 is formed. Arrange to close. Similarly, when the partition plate 42 is disposed, the pressing force by the shield jack 47 is applied.

  Next, the process proceeds to the construction of a narrow tunnel 30 having a narrow tunnel width. At this time, as shown in FIG. 5A, the shield jack installation member 46 is shifted toward the inside of the tunnel, and a pressing force is applied to the segment 31 using the shield jack 47. One end of the segment 31 is attached to the partition plate 42. The water stop box 24 may be attached to the shield jack installation member 46 so as to be in contact with the segment 31 from the viewpoint of preventing underground moisture from entering the tunnel.

Next, as shown in FIG. 5 (b), the joining of the segment 31 in the axial direction G is repeatedly performed using the shield machine 44 . At this time, the backfilling material 25 is filled in an area outside the narrow tunnel 30 and surrounded by the partition plate 42 and the water stop box 24. Incidentally, at this stage, the segment 35 in the composite segment ring structure 39 is left as it is. Further, the tail brush 15 can be firmly prevented from entering soil water into the tunnel by contacting the segment 31 or the segment 21.

  Finally, after the construction of the tunnel is finished, the segment 35 in the composite segment ring structure 39 is removed as shown in FIG. Thereby, the junction in the axial direction of the narrow tunnel 30 with respect to the wide tunnel 20 having a wide tunnel width is completed.

  Such a heterogeneous tunnel junction method exhibits an advantageous effect particularly at the stage shown in FIGS. 5 (a) and 5 (b). When a pressing force is applied to the segment 31 using the shield jack 47, a force is transmitted in the direction of the arrow shown in FIG. That is, the pressing force transmitted to the segment 31 travels straight through the segment 35 as it is. However, the load flowing in the segment 35 is gradually transmitted to the segment 21 side through the connecting portion with the wide segment ring 21 as indicated by a dotted arrow. As a result, the pressing force from the shield jack 47 is not suddenly bent on the segment 21 side, and it is possible to prevent stress from being concentrated on the segments 31 and 35. As a result, the segments 31 and 35 do not become unstable. In FIG. 6, the segment indicated by the dotted line indicates a modified form of the segments 31 and 35 due to the pressing force from the shield jack 47 being applied. It can be seen that the amount of deformation can be suppressed to a very small degree because it can be transmitted to the segment 21 side by little without causing stress concentration at the predetermined locations of the segments 31 and 35.

  Next, another embodiment of the heterogeneous tunnel junction method to which the present invention is applied will be described in detail with reference to the drawings.

This dissimilar tunnel joining method joins a wide tunnel 20 having a wide tunnel width to a narrow tunnel 30 having a narrow tunnel width when excavating a tunnel based on a shield method. First, as shown in FIG. 7A, a narrow tunnel 30 is constructed based on a shield method. At this time, the shield machine 44 is used to excavate the natural ground 49 and repeat the operation of installing the segment 31 along the inner periphery of the excavated mine. At this time, the joining of the segment 31 in the axial direction G is repeatedly performed using the shield machine 44 . At this time, the backfill material 25 is filled in a region outside the narrow tunnel 30 and surrounded by the water stop box 24. The region filled with the backfill material 25 is a region corresponding to the tunnel cross-section non-overlapping region 41.

  Next, as shown in FIG. 7 (b), after the construction of the narrow tunnel 30 is finished, the wall-like partition plate 42 is attached to the segment 31. At this time, the water stop box 24 is separated from the shield machine 44 and attached outside the segment ring 3 and in contact with the partition plate 42. Next, the segments 35 and 21 are attached to the partition plate 42, respectively. At this time, the process is similarly performed by applying a pressing force by the shield jack 47 in the shield machine 44.

  Next, as shown in FIG. 7C, the segment 35 and the segment 21 are continuously connected in the axial direction. In this way, the composite segment ring structure 39 is constructed.

  Next, as shown in FIG. 8A, after the construction of the composite segment ring structure 39 is finished, the axial connection of the segments 21 is continuously executed. At this stage, since the joining of the segment 35 is completed, the pressing force is applied to the shield jack 47 to the segment 21 with the shield jack installation member 46 shifted to the skin plate 45 side. By doing so, it will join.

  Next, as shown in FIG. 8B, the wide tunnel 20 is continuously constructed by repeatedly performing the joining of the segments 21 in the axial direction G.

  Finally, after the construction of the tunnel is finished, the segment 35 in the composite segment ring structure 39 is removed as shown in FIG. As a result, the joining of the wide tunnel 20 to the narrow tunnel 30 in the axial direction G is completed.

  Such a heterogeneous tunnel junction method exhibits an advantageous effect particularly at the stage shown in FIGS. 8 (a) and 8 (b). When a pressing force is applied to the segment 21 using the shield jack 47, a force is transmitted in the direction of the arrow shown in FIG. That is, the pressing force transmitted to the segment 21 travels straight through the segment 21 as it is. However, the load flowing in the segment 21 is gradually transmitted to the segment 35 side through the connecting portion with the wide segment ring 21 as indicated by the dotted arrow. As a result, the pressing force from the shield jack 47 is not suddenly bent on the segment 21 side, and it is possible to prevent stress from being concentrated. As a result, the segment 21 does not become unstable. In FIG. 9, a segment indicated by a dotted line indicates a modified form of the segment 21 due to the pressing force from the shield jack 47 being applied. It can be understood that the amount of deformation can be suppressed to a very small degree because the stress can be dispersed and transmitted to the segment 35 little by little without causing stress concentration at a predetermined location of the segment 21.

  Thus, the heterogeneous tunnel junction method to which the present invention is applied has the composite segment ring structure 39. That is, the reinforcing segment ring 35 ′ composed of the segments 35 is constructed inside the wide tunnel 20, particularly in the vicinity of the tunnel junction 9. For this reason, when constructing the wide tunnel 20 or the narrow tunnel 30, when a pressing force is applied to the segment 21 or the segment 31 using the shield jack 47, the flow of stress can be made smooth. It is possible to reduce stress concentration.

  In addition, by constructing a reinforcing segment ring 35 ′ for the composite segment ring structure 39, particularly over a plurality of rings, and then shifting the shield jack installation member 46, the construction method for changing the jack pressing position, The rigidity against the jack thrust can be improved, and as a result, the deformation suppressing effect can be improved.

In particular, in the heterogeneous tunnel junction method to which the present invention is applied, since the composite segment ring structure 39 is constituted by the reinforcing segment ring 35 ', the construction can be completed only with the shield machine 44 without using a special heavy machine. it can. For this reason, it is possible to shorten the construction period, and it is possible to reduce the construction cost.

  In the above-described dissimilar tunnel junction method, the case where the reinforcing segment ring 35 ′ constituting the composite segment ring structure 39 is disposed over a plurality of rings has been described as an example, but the present invention is not limited to this. There may be at least one ring. However, in order to effectively distribute the stress and relieve the stress concentration on the segment 21 or the like, the reinforcing segment ring 35 ′ is arranged over a plurality of rings, and the stress is dispersed step by step. It is desirable.

  Further, the present invention is not limited to the above-described embodiment. For example, as shown in FIG. 10A, reinforcing vertical ribs 54 may be formed inside the steel shell of the segment 31 in the narrow segment ring 3 constituting the narrow tunnel 30. At this time, the reinforcing vertical ribs 54 are arranged so as to protrude from the natural mountain side of the segment 31 toward the inner sky surface side. Incidentally, the longitudinal ribs 54 are oriented in the axial direction in the longitudinal direction, and are arranged in a plurality of rows at predetermined intervals in the segment circumferential direction. FIG. 10B shows a perspective view of the segment 31 in which the reinforcing vertical ribs 54 are disposed. The longitudinal ribs 54 are arranged at predetermined intervals in the circumferential direction so that the longitudinal direction is the axial direction G. The reinforcing vertical rib 54 is formed with a flat plate-like flange 56 at the upper end as compared with a normal vertical rib, and the cross-sectional performance is set by setting the vertical rib cross-sectional height to be large and further increasing the plate thickness. Is configured high. Incidentally, a ring bolt hole 17 and a piece bolt hole 18 are formed in the steel shell constituting the segment 31, respectively.

  Such reinforcing vertical ribs 54 may also be formed in the segment 21 of the wide segment ring 2 in the same manner.

  In the narrow segment ring 3 in which such reinforcing vertical ribs 54 are formed, an effect of improving the member proof stress in the tunnel axial direction G (perpendicular to the plane of the paper in FIG. 10) is obtained, and is eccentric from the tunnel cross section. It becomes possible to suppress the lateral deformation of the tunnel cross section caused by the eccentric moment due to the pressing force of the jack. This side-to-side deformation of the tunnel cross section generates a large stress in the tunnel segment, making it difficult to ensure rigidity against jack thrust. Incidentally, the pressing position 55 in the drawing is a position where a pressing force is applied by the shield jack 47.

  The reinforcing vertical ribs 54 may be provided in all the segments 31 constituting the narrow segment ring 3 as described above, but may be provided only in a part of the segments 31 or one. Alternatively, it may be selectively provided only in a part of the segment 31.

  FIG. 11 shows a case where the reinforcing vertical ribs 54 are selectively formed, taking the C-C ′ cross section in FIG. 2 as an example. In this example, reinforcing vertical ribs 54 as tunnel axial direction reinforcing members are formed only in regions sandwiched by line segments P and Q passing through the tunnel center formed on both sides of the narrow-width segment ring 3, Outside the region, normal vertical ribs are provided (not shown). That is, it means that the reinforcing vertical rib 54 is provided in the tunnel cross-section non-overlapping region and / or the tunnel cross-section non-overlapping region. By selectively providing the reinforcing vertical ribs 54 in such a region, it is possible to effectively and economically resist the eccentric moment generated in the above-described tunnel cross section.

  FIG. 12 shows a case where the reinforcing vertical ribs 54 are formed over the entire circumference, taking the C-C ′ cross section in FIG. 2 as an example. By forming the reinforcing vertical ribs 54 over the entire circumference, it becomes possible to increase the member proof strength against stresses applied not only in the horizontal direction but also in all directions, so that the lateral deformation of the tunnel cross section can be prevented. The suppression effect is even greater.

  By providing the reinforcing member in the tunnel axial direction as described above, it is possible to effectively cope with the eccentric moment generated in the tunnel cross section, but this reinforcing member is limited to the above-described reinforcing vertical rib 54. Rather, the same effect can be achieved with reinforcing materials such as reinforcing bars.

  FIGS. 13A and 13B show an example in which a reinforcing member 59 is provided at a connection point between the reinforcing segment ring 35 ′ and the wide tunnel 20. That is, the reinforcing member 59 is provided at the axial end of the composite segment ring structure 39. The reinforcing member 59 is provided inside the wide segment ring 2 constituting the wide tunnel 20 and at one part 37 and / or another part 38 outside the steel shell constituting the wide segment ring 2. Become. The reinforcing member 59 may be made of steel or steel / concrete.

Such location providing the reinforcing member 59, when the pressing force by the shield jack 47 is loaded as shown in FIG. 13 (a), in particular with the reinforcing segment ring 35 ', the connection point between the wide tunnel 20 When thus stress is concentrated at, in the connection point, by providing the reinforcing member 59, it is possible to enhance the durability against the stress concentration.

It is a perspective view of a heterogeneous tunnel junction structure to which the present invention is applied. It is a top view of the heterogeneous tunnel junction structure to which this invention is applied. It is sectional drawing of the heterogeneous tunnel junction structure to which this invention is applied. It is the first half figure for demonstrating taking the case where a narrow tunnel is joined to a wide tunnel as an example about the heterogeneous tunnel junction method to which this invention is applied. It is the latter half figure for demonstrating the case where the narrow tunnel is joined to the wide tunnel as an example about the heterogeneous tunnel junction method to which this invention is applied. It is a figure for demonstrating the behavior at the time of giving pressing force with respect to a segment using a shield jack in the case of FIG. It is the first half figure for demonstrating the case where a wide tunnel is joined to a narrow tunnel about the heterogeneous tunnel junction method to which this invention is applied. It is the latter half figure for demonstrating the case where the wide tunnel is joined to the narrow tunnel about the heterogeneous tunnel junction method to which this invention is applied. It is a figure for demonstrating the behavior at the time of giving pressing force with respect to a segment using a shield jack in the case of FIG. It is a figure which shows the example which forms a vertical rib inside the steel shell of the segment in a segment ring. It is a figure which shows the example which selectively forms a vertical rib inside the steel shell of the segment in a segment ring. It is a figure which shows the example which forms a vertical rib over the perimeter inside the steel shell of the segment in a segment ring. It is a figure which shows the example which provided the reinforcement member in the connection point of a narrow segment ring and a wide tunnel. It is a figure for demonstrating a prior art. It is a figure for demonstrating the problem of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heterogeneous tunnel junction structure 2 Wide segment ring 3 Narrow segment ring 9 Tunnel junction 15 Tail brush 20 Wide tunnel 21, 31, 35 Segment 24 Water stop box 25 Backfill material 30 Narrow tunnel 35 'Segment ring 37 for reinforcement, 38 Site 39 Composite segment ring structure 41 Tunnel cross-section non-overlapping area 42 Bulkhead plate 44 Shield machine 45 Skin plate 46 Shield jack installation member 47 Shield jack 48 Face plate 49 Ground 54 Reinforcement vertical rib 55 Press position 56 Flange 59 Reinforcement member

Claims (11)

In a heterogeneous tunnel junction structure in which a wide segment ring with a wide tunnel width and a narrow segment ring with a narrow tunnel width have an overlapping portion in the tunnel axis direction and are joined in the tunnel axis direction,
A reinforcing segment ring in which a segment is connected from one part of the wide segment ring to another part at a position corresponding to a non-overlapping part other than the overlapping part in the narrow segment ring inside the wide segment ring. Furthermore, the constructed composite segment ring structure is formed,
In the tunnel cross-section non-overlapping region of the cross section of the narrow segment ring and the wide segment ring at the tunnel junction, a partition plate having a shape corresponding to the region includes the reinforcing segment ring and the narrow segment ring. interposed between and heterologous tunnel junction structure, characterized in that is provided so as to close the region. The heterogeneous tunnel junction structure according to claim 1, wherein the composite segment ring structure is formed across a plurality of rings toward the tunnel axis direction. The heterogeneous tunnel junction structure according to claim 1, wherein a tunnel axial direction reinforcing member is provided inside a segment of the wide segment ring and / or the narrow segment ring. The heterogeneous tunnel junction structure according to claim 3, wherein the tunnel axial direction reinforcing member is provided in the tunnel cross-section non-overlapping region and / or the tunnel cross-section non-overlapping region. Reinforcing members are provided at the one part and / or the other part inside the wide segment ring and outside the steel shell constituting the wide segment ring at the tunnel axial direction end in the composite segment ring structure. The heterogeneous tunnel junction structure according to any one of claims 1 to 4, wherein the heterogeneous tunnel junction structure is provided. In a heterogeneous tunnel junction method in which a wide segment ring with a wide tunnel width and a narrow segment ring with a narrow tunnel width are joined to each other in the tunnel axis direction with overlapping portions in the tunnel axis direction based on the shield method,
The wide segment ring is constructed on the end side of the wide tunnel when the tunnel width is changed from wide to narrow , and the non-overlapping part other than the overlapping part in the narrow segment ring inside the wide segment ring in a position corresponding, to form a further composite segment ring structure constructed reinforcing segment ring linked segments from one site over the other parts of the wide segment ring,
Between the wide segment ring and the narrow segment ring to be joined , at least a surface of the partition plate having a shape corresponding to a tunnel cross-section non-overlapping region of the cross section of the reinforcing segment ring and the wide segment ring , Provided to close the tunnel cross-section non-overlapping region while contacting the end face of the reinforcing segment ring ,
The heterogeneous tunnel junction method further comprising sequentially constructing the narrow segment ring from the partition plate toward the tunnel axis direction. The heterogeneous tunnel junction method according to claim 6, wherein the composite segment ring structure is formed across a plurality of rings in the tunnel axis direction. In constructing the reinforcing segment ring, the composite segment ring structure is formed by connecting segments from one part to the other part inside the wide segment ring, and further from the partition plate in the tunnel axial direction. The heterogeneous tunnel junction method according to claim 6 or 7, wherein the reinforcing segment ring is removed after the narrow-width segment rings are sequentially constructed toward the surface. In a heterogeneous tunnel junction method in which a wide segment ring with a wide tunnel width and a narrow segment ring with a narrow tunnel width are bonded to each other in the tunnel axis direction based on the shield method,
When constructing the above narrow segment rings sequentially and shifting the tunnel width from narrow to wide,
A partition plate having a shape corresponding to a tunnel cross-section non-overlapping region of a cross section with the wide segment ring to be bonded to the narrow segment ring is provided in the narrow segment ring,
The wide segment ring is constructed from the partition plate in the tunnel axis direction, and the wide segment ring is positioned inside the wide segment ring at a position corresponding to a non-overlapping portion other than the overlapping portion in the narrow segment ring. A reinforcing segment ring in which segments are connected from one part to another part forms a composite segment ring structure constructed so that the partition plate is interposed between the narrow segment ring ,
Furthermore, the heterogeneous tunnel junction method characterized by sequentially constructing the wide segment ring. The heterogeneous tunnel junction method according to claim 9, wherein the composite segment ring structure is formed across a plurality of rings in a tunnel axis direction. After sequentially build the wide segment ring further toward the tunnel axis from the composite segment ring structure, heterologous tunnel bonding method according to claim 9 or 10, characterized in that removing the above-mentioned reinforcement segment ring.

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