Ring joint structure, segment structure, and segment ring structure

Abstract

The present invention provides a segment ring structure that can maintain the structural performance of the tunnel while suppressing the falling of concrete blocks due to segment damage. [Solution] The first inter-ring joint 20A, which is closest to the segment joint surface 13a in the tunnel circumferential direction X1 among the inter-ring joints 20, is provided so as to be movable on both sides in the tunnel circumferential direction X1 relative to another second inter-ring joint 20B that connects to the first inter-ring joint 20A, in the state immediately after the segment 10 is assembled to the adjacent segment 10, and at least one of the first inter-ring joint 10A and the second inter-ring joint 20B has an elongated hole 22 that guides the other in the tunnel circumferential direction X1.

Description

Technical Field

[0001] The present invention relates to a ring joint structure, a segment structure, and a segment ring structure.

Background Art

[0002] Conventionally, the shield method is a method of constructing a tunnel by excavating with a shield machine and then assembling segments that will form the tunnel wall surface behind it. In this method, since the segments are prefabricated in a factory and assembled on site, it is excellent in terms of workability and quality. Generally, an arc-shaped segment includes a segment joint that connects segments in the circumferential direction of the tunnel and a ring joint that connects them in the axial direction of the tunnel. Then, the segments are assembled into a cylindrical shape by connecting the segment joints to form a segment ring. Further, the segments are arranged such that the circumferential joint surfaces (segment joint surfaces) of adjacent segment rings are staggered in a checkerboard pattern, and an adjacent bending moment is transmitted between adjacent segment rings via the ring joint. That is, the bending moment generated during tunnel deformation is transmitted through the segment joint or dispersed to adjacent segment rings via the ring joint.

[0003] By the way, earthquakes of a scale exceeding conventional assumptions have occurred, and there is a need for technology to suppress human casualties in the tunnel even when unexpected earthquakes and accompanying ground deformation occur. For example, there are cases where disasters such as the concrete of the tunnel lining falling occur, and reducing the risk of damage to the tunnel lining also leads to the suppression of human casualties. In shield tunnels, especially when RC segments or composite segments are used, there are concerns about damage to the segments and the accompanying fall of concrete blocks.

[0004] Furthermore, in recent years, with the increasing severity of natural disasters, the construction of underground river tunnels is progressing to temporarily store rainwater by constructing underground tunnels directly beneath main roads and other locations to cope with flooding damage in urban areas. Conventionally, in underground tunnel linings, axial compressive force is predominantly acted in the circumferential direction of the segment rings due to soil and water pressure from the surrounding tunnel. Therefore, in order to effectively counteract this axial compressive force, it was common to use concrete materials that are resistant to compression, according to their stress characteristics, for the tunnel lining structure, and to use joint structures at the segment joints where the joint surfaces abut each other to transmit compressive force. However, in underground tunnels filled to capacity with rainwater, internal water pressure acts from the inside to the outside of the tunnel, resulting in axial tensile force acting in the circumferential direction of the segment rings. As a result, there is a concern that the segment joint surfaces will separate and open up, and that the joint structure, which is unsuitable for counteracting axial tensile force, may be damaged. Therefore, it was necessary to solve the problem of reducing the risk of joint damage by suppressing the opening of the segment joint surfaces. Therefore, segments are known that improve the connecting force between segment joints by providing irregularities on the joint surface between rings in the direction of the segment ring axis (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 10-299396 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the conventional segments described above, as shown in Patent Document 1, are characterized by increasing the restraining force in the circumferential direction of the tunnel and suppressing the opening between segment joints. However, this displacement due to the opening is concentrated near the segment joints where the displacement is particularly large and transmitted to adjacent segments in the segment ring axis direction, resulting in a problem where cracks in the segment concrete are concentrated near the segment joints. Furthermore, even if gaps occur in the segment joint surface or if fractures occur in the segment joint, if the fastening force of the inter-ring joint is large, a tensile force equivalent to the gap will be generated in the adjacent segment in the tunnel axial direction, which can cause damage to the concrete of the adjacent segment in particular, potentially leading to the fall of concrete fragments. Therefore, there was room for improvement in this respect. For the above reasons, it is necessary to reduce the risk of joint damage and ensure the structural performance of the tunnel lining by suppressing gaps in the segment joint surface, while simultaneously reducing the risk of concrete cracking that occurs concentrated around the segment joints.

[0007] This invention has been made in view of the above-mentioned problems, and aims to provide a ring joint structure, a segment structure, and a segment ring structure that can suppress the falling of concrete blocks due to segment damage while maintaining the structural performance of the tunnel. [Means for solving the problem]

[0008] (1) Embodiment 1 of the inter-ring joint structure according to the present invention is an inter-ring joint structure that connects arc-shaped segments that are connected in a plurality in the circumferential direction to form a segment ring, in the segment ring axis direction, wherein the segment has a pair of segment joint surfaces arranged opposite to each other in the circumferential direction, a pair of inter-ring joint surfaces arranged opposite to each other in the segment ring axis direction, and a pair of arc surfaces arranged along the circumferential direction, the segment joint surfaces are provided with segment joints that connect the segments in the circumferential direction, and the inter-ring joint surfaces are provided with adjacent segment joints adjacent to each other in the segment ring axis direction The segment is provided with inter-ring joints that connect to the segments, the segment joint surfaces are arranged alternately in the circumferential direction with other segment joint surfaces of the adjacent segments, the first inter-ring joint that is closest to the segment joint surface in the circumferential direction is connected to the first inter-ring joint when the segment is assembled to the adjacent segment, and is provided so as to be movable on both sides in the circumferential direction with respect to a second inter-ring joint arranged on the adjacent segment, and at least one of the first inter-ring joint and the second inter-ring joint has a guide portion that guides the other in the circumferential direction.

[0009] In this invention, when adjacent segments are assembled in the axial direction of the segment ring, the inter-ring joints are provided to be movable on both sides in the circumferential direction along a guide portion provided on at least one of the first inter-ring joint near the segment joint that is most affected by the opening of the segment joint surface, and another second inter-ring joint connected to the first inter-ring joint. This allows the inter-ring joints to slide only in the circumferential direction, thereby reducing the circumferential resistance while maintaining the radial resistance that affects the splice bending moment at adjacent inter-ring joint surfaces. Therefore, even if an opening occurs between segment joint surfaces connected in the circumferential direction, the inter-ring joints allow the segments to slide in the circumferential direction, suppressing the concentration and transmission of tensile force to adjacent segments near the segment joints, and thereby suppressing damage to the segments due to concrete cracking. Furthermore, in this invention, immediately after adjacent segments in the segment ring axial direction are assembled, the first inter-ring joint and the second inter-ring joint are relatively movable on both sides in the circumferential direction, and the structure allows for displacement on both sides in the circumferential direction. Therefore, the above effect can be achieved regardless of which direction the segments slide in the circumferential direction. At the same time, in a segment joint to which the present invention is applied, resistance in the circumferential direction is exerted against the inter-ring joints, excluding the inter-ring joint closest to the segment joint surface. This has the effect of suppressing the opening of the segment joint surface, thereby reducing the risk of joint fracture. In other words, in the case of an underground river tunnel, a combined behavior occurs in the segment joint: when soil and water pressure loads act from the outer circumference of the tunnel, the inner sides of the segment joint surfaces open in the circumferential direction and the outer sides remain tightly closed; and when internal water pressure loads act from the inner circumference of the tunnel, both the inner and outer sides of the segment joint surfaces open in the circumferential direction. In the segment joint of the present invention, resistance in the circumferential direction is exerted against the displacement caused by the opening of the segment joint and propagated in the circumferential direction, immediately after the segment rings are assembled, with respect to the inter-ring joints, excluding the inter-ring joint closest to the segment joint surface. This has the effect of suppressing the movement of the inner and outer sides of the segment joint surfaces opening in the circumferential direction. Therefore, the gap between segment joint surfaces can be suppressed, reducing the risk of joint damage and ensuring the structural performance of the tunnel lining. Conventionally, in order to suppress the gap between segment joints, the approach has been to directly restrain the movement of the joint in the direction of separation between the segment joints, or to restrain it near the joint. However, as a result of analyzing the relationship between external forces acting on the tunnel and the gap between segment joints, it was found that by restraining the movement of the joint at a point away from the segment joint surface where the circumferential displacement is relatively small, the gap between segment joints is dispersed and suppressed in the circumferential direction. Thus, the present invention makes it possible to suppress the falling of concrete blocks due to segment damage while maintaining the structural performance of the tunnel.

[0010] (2) Aspect 2 of the present invention is a ring joint structure of aspect 1, characterized in that the ring joint has a third ring joint between the first and second ring joints that are adjacent in the circumferential direction, the third ring joint being constrained to move on both sides in the circumferential direction.

[0011] In this case, the third inter-ring joint, which restricts circumferential movement while allowing circumferential displacement of the inter-ring joint near the segment joint and preventing damage to the segment, can suppress excessive opening behavior of the segment joint surface.

[0012] (3) Embodiment 3 of the present invention is characterized in that, in the inter-ring joint structure of Embodiment 1, the joint is provided along the circumferential direction within a range of distance from the segment joint surface to twice the radial height of the segment.

[0013] We found that the circumferential displacement due to the opening of the segment joint surface depends on the opening angle and the segment height, and that the propagation of this displacement is concentrated in an area approximately twice the segment height from the segment joint surface. Therefore, by making the inter-ring joints, which are positioned in an area twice the segment height circumferentially from the segment joint surface, movable in the circumferential direction, the propagation of tensile force to adjacent segments by the inter-ring joints can be efficiently suppressed, thereby reducing segment damage due to concrete cracking.

[0014] (4) Aspect 4 of the present invention is a ring joint structure in any one of aspects 1 to 3, wherein the ring joint is a joint structure in which a male part is inserted into a female part, and the female part having a through hole or a recessed hole that does not penetrate into which the male part can be inserted is provided on the ring joint plate of at least one of the first ring joint and the second ring joint, the female part is the guide part and is composed of an elongated hole in which the diameter of the hole in the circumferential direction is larger than the diameter of the hole in the radial direction, and the male part is characterized in that the circumferential loose fit when inserted into the female part is larger than the radial loose fit.

[0015] In this case, even with discretely arranged inter-ring joints, a configuration that allows the segments to slide circumferentially can be easily achieved by making the through-hole or recessed hole in the female part a long, elongated hole in the circumferential direction. Furthermore, by providing a circumferential clearance in the loose fitting between the male and female parts, the effect of sliding circumferentially can be achieved while preventing radial displacement. In addition, a cushioning material including a rubber-like filler may be inserted in the loose fitting between the male and female parts.

[0016] (5) Aspect 5 of the present invention is a ring joint structure of aspect 4, wherein the ring joint plate is provided in both the first ring joint and the second ring joint, and the male portion is preferably passed through the through holes of the ring joint plates of the first ring joint and the second ring joint simultaneously.

[0017] In the present invention, even if the male part is a ring joint such as a fastening bolt, by making the through holes in the ring joint plates of the first and second ring joints elongated in the circumferential direction, it is possible to easily realize a configuration in which the segment slides in the circumferential direction while increasing the amount of movement in the circumferential direction.

[0018] (6) Embodiment 6 of the present invention may be characterized in that, in the ring joint structure of Embodiment 4 or Embodiment 5, the through hole or recessed hole has a circumferential hole diameter ≥ radial hole diameter + 2 mm × 2.

[0019] In this case, by setting the circumferential diameter of the through hole or recessed hole to the radial diameter + 2 mm × 2, it is possible to reliably tolerate circumferential displacement due to the opening of the segment joint surface in a low-cost configuration.

[0020] (7) Embodiment 7 of the present invention is characterized in that, in any one of embodiments 4 to 6, the through hole or recessed hole has a positioning locking portion that is radially recessed at the position into which the male portion is inserted during segment assembly.

[0021] In this case, the male part can be locked to the positioning locking part that is recessed in the radial direction provided in the through hole or the recessed hole, and can be positioned in a circumferentially restrained state. Therefore, it is possible to suppress the segments adjacent to each other in the segment ring axial direction from being assembled in a state where they are shifted to either side in the circumferential direction in the long hole immediately after being assembled, and it is possible to reliably secure a movable play area for the male part in the long hole.

[0022] (8)Aspect 8 of the present invention may be characterized in that, in the ring joint structure of Aspect 1, the guide part is a circumferential guide part that extends along the curvature of the ring joint surface in the circumferential direction.

[0023] In this case, since the circumferential guide part extends with a curvature equivalent to the curvature of the ring joint surface in the circumferential direction, the processing of the ring joint surface of the segment becomes easy, and it is possible to reduce the manufacturing cost. Further, in the present invention, it is possible to easily realize a configuration for sliding the segment in the circumferential direction, and it is possible to increase the relative movement length in the circumferential direction between segments adjacent to each other in the segment ring axial direction.

[0024] (9)Aspect 9 of the present invention may be characterized in that, in the ring joint structure of Aspect 7, the circumferential guide part continuously extends over the entire circumferential direction of the ring joint surface.

[0025] In this case, since the circumferential guide part is continuous in the circumferential direction, it is possible to easily perform fitting and fine adjustment of the segment during assembly of the segment. Therefore, it is possible to improve workability. In addition, a structure may be provided to make it slippery by applying silicon or oil between adjacent ring joint surfaces to reduce friction in the circumferential direction.

[0026] (10)Aspect 10 of the present invention is preferably such that, in the ring joint structure of Aspect 8, the circumferential guide part is provided, and a device for restraining movement in the circumferential direction is arranged on the ring joint surface.

[0027] In this case, the circumferential guide allows for circumferential displacement of the inter-ring joint surface near the segment joint, effectively preventing damage to the segments, while the circumferential restraining device suppresses excessive opening of the segment joint surface. The circumferential restraining device may be mechanical or bolted, and it is desirable that multiple devices be placed on the inter-ring joint surface.

[0028] (11) Embodiment 11 of the present invention is characterized in that, in the inter-ring joint structure of Embodiment 10, the device is positioned along the circumferential direction at a distance of more than 1x the radial height of the segment from the segment joint surface.

[0029] The circumferential displacement due to the opening of the segment joint surface depends on the opening angle and the segment height. However, in the case of a continuous circumferential guide section, the effect of circumferential displacement is high, and the structure is such that the effect of opening easily propagates. Therefore, it is preferable to place a jig that restrains circumferential displacement at a distance of more than 1x the segment height from the segment joint surface.

[0030] (12) Embodiment 12 of the segment structure according to the present invention is characterized by comprising one of the ring joint structures from Embodiments 1 to 11.

[0031] Generally, the joints between rings are integrated with the segments. By adopting segments with the features of the present invention, tunnels exhibiting the above effects can be constructed without modifying conventional shield machines, thereby improving productivity.

[0032] (13) Embodiment 13 of the segment ring structure according to the present invention is characterized by comprising one of the inter-ring joint structures from Embodiment 1 to Embodiment 11.

[0033] By employing the inter-ring joint structure of the present invention in the segment ring, it can be effective against various ground deformations. The inter-ring joint structure of the present invention may be applied to all or only a portion of the segment ring. [Effects of the Invention]

[0034] According to the ring joint structure, segment structure, and segment ring structure of the present invention, it is possible to suppress the falling of concrete blocks due to segment damage while maintaining the structural performance of the tunnel. [Brief explanation of the drawing]

[0035] [Figure 1] This is a partially broken perspective view showing the main part of the segment ring structure of a shield tunnel according to the first embodiment of the present invention. [Figure 2] Figure 1 is a perspective view showing the segments. [Figure 3] This is a perspective view showing the inter-ring joints of a segment ring structure, where (a) is a diagram showing an example of an inter-ring joint, and (b) is a diagram showing another example of an inter-ring joint. [Figure 4] (a) is a plan view of the ring joint, and (b) is a plan view of the ring joint with a positioning locking section. [Figure 5] This is a perspective view showing the arrangement of inter-ring joints in a shield tunnel. [Figure 6] This is a plan view showing the arrangement of the ring joints between segments. [Figure 7] This is a perspective view showing the arrangement of sealing material provided on the segment joint surface. [Figure 8] This is a side view showing the segment with the sealing material in place in an open state. [Figure 9] This is a perspective view showing a segment according to the second embodiment. [Figure 10] Figure 9 is a cross-sectional view showing the state before adjacent segments in the tunnel axis direction are connected. [Figure 11]This is a perspective view showing a segment according to the third embodiment. [Figure 12] This is a side view showing a segment according to the fourth embodiment. [Figure 13] (a) and (b) are diagrams showing beam-spring models according to the examples. [Figure 14] (a) and (b) are axial force diagrams showing the analysis results of the embodiment. [Figure 15] This figure shows the analysis results comparing the axial force in the example and comparative example. [Figure 16] This figure shows the analysis results comparing the bending moments of the examples and comparative examples. [Modes for carrying out the invention]

[0036] The following describes, with reference to the drawings, the inter-ring joint structure, segment structure, and segment ring structure according to embodiments of the present invention.

[0037] (First Embodiment) As shown in Figures 1 and 2, the shield tunnel 100 (shield tunnel ring structure) according to this embodiment includes an inter-ring joint structure 1 that connects segment rings R, each consisting of arc-shaped segments 10 connected in the circumferential direction (tunnel circumferential direction X1), in the segment ring axis direction X2.

[0038] Segment 10 constitutes a segment ring R, which is a structural member of the circular cross-section tunnel lining constructed on the inner wall of the hole excavated by the shield tunneling method. In this embodiment, segment 10 will be described as a composite segment filled with concrete as an example. Segment 10 may also be an RC segment, which is a combination of reinforcing steel and concrete.

[0039] Here, in segment 10, the arc direction is called the tunnel circumferential direction X1 (circumferential direction), the short side direction perpendicular to the arc direction is called the segment ring axis direction X2, and the height direction of segment 10 is called the tunnel radial direction X3. Also, in the tunnel radial direction X3, the outer side is called the ground side (tunnel ground side), and the inner side is called the interior side (tunnel interior side).

[0040] In the shield tunneling method, multiple segments 10 are connected along the inner wall of the excavated hole of the tunnel, which is excavated in the natural ground, in the circumferential direction X1 of the tunnel and in the axial direction X2 of the segment ring, to construct a cylindrical wall. Segment 10 is formed in the shape of an arc with a curvature approximately equal to the curvature of the inner surface of the excavated hole of the tunnel. That is, segment 10 has a hexahedral shape that is curved in an arc on the outer surface of the tunnel.

[0041] Segment 10 includes an inter-ring joint 20 and a segment joint 15. Segment 10 has a pair of inter-ring joint surfaces 11a arranged opposite to each other in the segment ring axis direction X2, a pair of segment joint surfaces 13a arranged opposite to each other in the tunnel circumferential direction X1, and a pair of arcuate surfaces arranged along the tunnel circumferential direction X1.

[0042] The ring joint structure 1 of this embodiment is a structure in which segment rings, each consisting of arc-shaped segments 10 constituting a shield tunnel 100 connected in the tunnel circumferential direction X1 by a segment joint surface 13, are connected to each other in the segment ring axial direction X2 by a ring joint 20.

[0043] Segment 10 is assembled in a staggered arrangement in which the connection positions of adjacent segment rings R in the tunnel circumferential direction X1 are shifted in the tunnel circumferential direction X1 along the tunnel axis X2. That is, one A-ring and the other B-ring of adjacent segment rings are arranged alternately along the segment ring axis X2. Alternatively, the segment rings may be arranged in a staggered arrangement with 3 rings forming one set.

[0044] Within the concrete of segment 10 (the infill concrete 14 described later), multiple main reinforcing bars are arranged in an arc shape in the tunnel circumferential direction X1 on both the interior and ground sides, and reinforcing ribs are placed as needed. The size of segment 10 can be changed as appropriate depending on transportability, assembly, etc. The curvature of the arc of segment 10 is appropriately determined by the cross-section of the tunnel to be excavated.

[0045] Segment 10 comprises a pair of main girders 11, 11 (ring joint plates) facing each other in the tunnel axis direction X2, a skin plate 12 positioned on the tunnel ground side, and a pair of joint plates 13, 13 provided at the ends of the pair of main girders 11, 11 and the skin plate 12 in the tunnel circumferential direction X1. Segment 10 is constructed in a substantially arc-shaped plate form by filling the area enclosed by the pair of steel main girders 11, 11, the pair of steel joint plates 13, 13 and the skin plate 12 with concrete 14.

[0046] As mentioned above, the skin plate 12 is installed on the ground side of the segment 10. The skin plate 12 is made of steel plate and is positioned to close the ground-side openings between the pair of main girders 11, 11 and the pair of joint plates 13, 13, which are assembled in a frame-like shape. The skin plate 12 is fixed to the ground-side periphery of the main girders 11 and joint plates 13 by welding. The skin plate 12 prevents the infill concrete 14 from flowing out to the outside and also prevents water and soil from the ground from penetrating into the steel shell. It can also be used as formwork when pouring the infill concrete 14.

[0047] As shown in Figure 2, the infill concrete 14 is filled into the steel shell so as to be flush with the inner end face. The infill concrete 14 is appropriately selected from ordinary concrete, high-strength concrete, high-flow concrete, fiber-reinforced concrete, etc., depending on the stress acting on the tunnel lining and the cross-sectional shape of the tunnel.

[0048] The joint plate 13 is provided at both ends in the tunnel circumferential direction X1 and includes segment joints 15 that correspond to inter-piece joints, bringing the segment joint surfaces 13a of the joint plate 13 of other segments 10 adjacent to it in the tunnel circumferential direction X1 into contact with each other. In other words, multiple (two in this case) segment joints 15 are arranged on the segment joint surface 13a, connecting the segments 10 in the tunnel circumferential direction X1. The segment joint surfaces 13a are arranged alternately in the tunnel circumferential direction X1 with other segment joint surfaces 13a of adjacent segment rings adjacent in the tunnel axial direction X2.

[0049] The segment joint 15 is positioned approximately in the center of the joint plate 13 in the height direction X3. The segment joint 15 has, for example, a male joint provided on one joint plate 13 in the tunnel circumferential direction X1, and a female joint on the other joint plate, and is configured to connect to the female joint and male joint in other segments 10 adjacent to the tunnel circumferential direction X1, respectively. As such a segment joint 15, well-known types such as bolt joints, pin joints, or mechanical joints can be used.

[0050] A pair of main girders 11, 11 are arranged parallel to each other with a gap in the segment ring axis direction X2, and the ends of each main girder 11, 11 in the tunnel circumferential direction X1 are connected by joint plates 13. Skin plates 12 are welded to the ground-side periphery of each of the pair of main girders 11, 11 and the pair of joint plates 13, 13. In other words, segment 10 forms a steel shell section framed by the pair of main girders 11, 11, the pair of joint plates 13, 13, and the skin plates 12. The inside of this steel shell section is filled with infill concrete 14.

[0051] The main girder 11 is provided with inter-ring joints 20 for connecting with other segments 10 adjacent to it in the tunnel axis direction X2. Multiple inter-ring joints 20 (four in this case) are provided on the surface of the main girder 11 facing the segment ring axis direction X2 (inter-ring joint surface 11a). The arrangement of the inter-ring joints may be at equal or unequal intervals. The inter-ring joints 20 connect the segments 10 in the segment ring axis direction X2. Here, the arrangement of inter-ring joints on the inter-ring joint surface 11a being at equal intervals means that the inter-ring joint surface 11a extending along the tunnel circumferential direction X1 is arranged at a constant interval in the tunnel circumferential direction X1.

[0052] The inter-ring joint 20 is positioned approximately in the center of the inter-ring joint surface 11a in the height direction X3. The inter-ring joint 20 is configured such that, for example, a male joint is provided on one main girder 11 in the segment ring axis direction X2, and a female joint is provided on the other main girder 11, and these are connected to the female joint and male joint on the adjacent other segment 10. As such an inter-ring joint 20, well-known types such as bolted joints, pin joints, interlocking joints, or mechanical joints can be used.

[0053] As shown in Figures 3 and 4(a), of the four inter-ring joints 20 provided on one side of the inter-ring joint surface 11a, the first inter-ring joint 20A, which is closest to the segment joint surface 13a in the tunnel circumferential direction X1, is provided so as to be movable on both sides in the tunnel circumferential direction X1 relative to another second inter-ring joint 20B that connects to the first inter-ring joint 20A, immediately after the segment 10 has been assembled with the adjacent segment 10 in the tunnel axial direction X2.

[0054] As shown in Figure 3(a), the first ring joint 20A has a fastening bolt 21 (male part). The second ring joint 20B has an elongated hole 22 (guide part, through hole) that guides the other (fastening bolt 21) in the tunnel circumferential direction X1. As shown in Figure 4(a), the elongated hole 22 is the female part, and is an elongated hole in which the hole diameter d1 in the tunnel circumferential direction X1 is larger than the hole diameter d2 in the tunnel radial direction X3. The hole diameter d1 of the elongated hole 22 in the tunnel circumferential direction X1 is expressed by formula (1). With the fastening bolt 21 positioned at the center of the elongated hole 22 in the tunnel circumferential direction X1, the length from the shaft portion 21a of the fastening bolt 21 to the longitudinal end portion 22a of the elongated hole 22 (indicated by d3 in Figure 4(a)) is set to 2 mm. d1 ≥ d2 + 2mm × 2 ···(1)

[0055] The reason for setting the length from the shaft portion 21a of the fastening bolt 21 to the longitudinal end portion 22a of the elongated hole 22 to 2 mm is based on the "Design of Segments" (Tunnel Library No. 23) of the Japan Society of Civil Engineers, which sets the circumferential displacement of the tunnel due to the opening of the segment joint to 2 mm or more.

[0056] The inter-ring joint 20 connects adjacent segments 10 in the segment-ring direction X2 by inserting fastening bolts 21 into elongated holes 22 and tightening nuts (not shown) onto the tips of the fastening bolts 21 that have passed through the elongated holes 22.

[0057] In the modified example shown in Figure 3(b), the first ring joint 20A and the second ring joint 20B each have an elongated hole 22 (guide portion, through hole) that guides the other in the tunnel circumferential direction X1. The first ring joint 20A has a fastening bolt 21 (male portion) and a first elongated hole 22A. The second ring joint 20B has a second elongated hole 22B (female portion). As shown in Figure 4(a), the elongated holes 22A and 22B are elongated holes in which the hole diameter d1 in the tunnel circumferential direction X1 is larger than the hole diameter d2 in the tunnel radial direction X3. The hole diameter d1 in the tunnel circumferential direction X1 of the elongated holes 22A and 22B is expressed by the formula (1) described above.

[0058] The ring joint 20 connects adjacent segments 10 in the segment ring direction X2 by simultaneously inserting fastening bolts 21 into the first elongated hole 22A and the second elongated hole 22B, and tightening a nut (not shown) onto the tip of the fastening bolt 21 that has passed through the second elongated hole 22B.

[0059] As shown in Figure 4(b), the elongated hole 22 has a positioning locking portion 22b that is recessed in the tunnel radial direction X3 at the position where the fastening bolt 21 is inserted during segment assembly. By providing the positioning locking portion 22b, the fastening bolt 21 can be easily positioned relative to the longitudinal center of the elongated hole 22 when it is passed through the elongated hole 22.

[0060] Figure 5 is a perspective view showing the arrangement of the inter-ring joint structure 1 in the shield tunnel 100. Figure 6 is a plan view showing the arrangement of the inter-ring joint structure 1. As shown in Figures 5 and 6, the first inter-ring joint 20A is positioned at a distance from the segment joint surface 11a that is within twice (2H) the radial height H of the segment 10 (see Figure 2). More preferably, it is within one time of the radial height H of the segment 10.

[0061] As shown in Figures 7 and 8, seal grooves are dug in a pair of main girders 11, 11 and a pair of joint plates 13, 13, and sealant 16 is installed therein to prevent water and soil from the ground from flowing into the interior space between a segment 10 and an adjacent segment 10. In Figure 8, the sealant 16 provided on the main girder 11 is omitted. The sealant 16 is arranged along the tunnel circumferential direction X1 in the main girder 11 and along the tunnel axial direction X2 in the joint plate 13. The sealant 16 is arranged on the inner circumferential side (inner circumferential sealant 16A) and outer circumferential side (outer circumferential sealant 16B) of the pair of main girders 11, 11 and the pair of joint plates 13, 13. The sealant 16 is water-swellable rubber or a gasket, and the shape of the seal groove and the type of sealant are appropriately determined according to the condition of the surrounding ground.

[0062] As shown in Figure 8, for example, when an external force such as soil and water pressure acts on the tunnel from above to below, even if the inner circumference (lower side) of the segment joint surfaces 13a, 13a of the upper segment of the tunnel opens up, the outer circumference (upper side) sealing material 16B remains in close contact with each other. Therefore, watertightness can be maintained.

[0063] According to the ring joint structure 1 described above, when adjacent segments 10 in the tunnel axis direction X2 are assembled, the ring joints 20 are provided so as to be movable on both sides in the tunnel circumferential direction X1 along an elongated hole 22 provided in at least one of the first ring joint 20A, which is near the segment joint that is most affected by the opening of the segment joint surface 13a, and another second ring joint 20B connected to the first ring joint 20A. As a result, the inter-ring joint 20 is allowed to slide only in the tunnel circumferential direction X1, which reduces the resistance force in the tunnel circumferential direction X1 while maintaining the radial resistance force that affects the splice bending moment at adjacent inter-ring joint surfaces 11a, and at the same time suppresses the opening of the segment joints. Therefore, even if an opening occurs between the segment joint surfaces 11a connected in the tunnel circumferential direction X1, the amount of opening is minimized, and the inter-ring joint 20 allows the segment 10 to slide in the tunnel circumferential direction X1, which suppresses the concentration and transmission of tensile force to adjacent segments 10, and suppresses damage to the segment 10 due to concrete cracking.

[0064] Furthermore, in this embodiment, immediately after the assembly of adjacent segments 10 in the tunnel axis direction X2, the first ring joint 20A and the second ring joint 20B are relatively movable on both sides in the tunnel circumferential direction X1. This structure allows for displacement on both sides in the tunnel circumferential direction X1, so the above effect can be achieved regardless of which direction the segment 10 slides in the tunnel circumferential direction X1. Thus, in this embodiment, it is possible to suppress the falling of concrete blocks due to damage to the segment 10 while maintaining the structural performance of the tunnel.

[0065] Furthermore, in this embodiment, as shown in Figure 6, it is provided along the tunnel circumferential direction X1, within a distance from the segment joint surface 13a to twice the radial height H (see Figure 2) of the segment 10. With this configuration, it was found that the displacement in the tunnel circumferential direction X1 due to the opening of the segment joint surface 13a depends on the opening angle and the segment height H, and that the propagation of this displacement is concentrated in an area from the segment joint surface 13a to about twice the segment height H. Therefore, by making the inter-ring joint 20, which is located in an area from the segment joint surface 13a to the tunnel circumferential direction X1 to be movable in the tunnel circumferential direction X1, the propagation of tensile force to adjacent segments by the inter-ring joint 20 can be efficiently suppressed, and damage to the segment 10 due to concrete cracking can be suppressed.

[0066] Furthermore, in this embodiment, the main girder 11 has a joint structure in which fastening bolts 21 are inserted into female mold parts (elongated holes 22). The main girder 11 is provided with female mold parts having through holes or recessed holes that do not penetrate, into which fastening bolts 21 can be inserted, in at least one of the first inter-ring joint 20A and the second inter-ring joint 20B. The through holes of the main girder 11 are guide parts and consist of elongated holes 22 in which the hole diameter in the tunnel circumferential direction X1 is larger than the hole diameter in the tunnel radial direction X3. When the male mold part is inserted into the female mold part, the loose fit in the tunnel circumferential direction X1 is larger than the loose fit in the radial direction. With this configuration, even if the inter-ring joints 20 are discretely arranged, by making the through-hole or recessed hole of the female part an elongated hole 22 that is long in the tunnel circumferential direction X1, it is easy to realize a configuration that allows the segment 10 to slide in the tunnel circumferential direction X1. In addition, by providing a clearance in the tunnel circumferential direction X1 for the loose fitting between the male and female parts, it is possible to prevent radial displacement while still providing the effect of sliding in the tunnel circumferential direction X1. Note that a cushioning material including a rubber-like packing may be inserted in the loose fitting between the male and female parts.

[0067] Furthermore, in this embodiment, the main girder 11 is provided in both the first ring joint 20A and the second ring joint 20B. The fastening bolts 21 are simultaneously passed through the respective through holes in the main girder 11 of the first ring joint 20A and the second ring joint 20B. With this configuration, even if the fastening bolts 21 are inter-ring joints, by making the through-holes in the main girder 11 of the first inter-ring joint 20A and the second inter-ring joint 20B both elongated holes 22 in the tunnel circumferential direction X1, it is possible to easily realize a configuration in which the segment 10 slides in the tunnel circumferential direction X1 while increasing the amount of movement in the tunnel circumferential direction X1.

[0068] Furthermore, in this embodiment, by setting the elongated hole 22 to have a hole diameter in the tunnel circumferential direction X1 ≥ the hole diameter in the tunnel radial direction X3 + 2 mm × 2, it is possible to reliably tolerate the displacement in the tunnel circumferential direction X1 due to the opening of the segment joint surface 13a with a low-cost configuration.

[0069] Furthermore, if the elongated hole 22 has a positioning locking portion 22b that is recessed in the tunnel radial direction X3 at the position where the fastening bolt 21 is inserted during segment assembly, the fastening bolt 21 can be locked into the positioning locking portion 22b provided in the elongated hole 22 and positioned while being constrained in the tunnel circumferential direction X1. Therefore, it is possible to prevent adjacent segments 10 in the tunnel axial direction X2 from being assembled in a state that is shifted to either side of the tunnel circumferential direction X1 in the elongated hole 22 immediately after assembly, and to reliably secure a movable play area for the fastening bolt 21 within the elongated hole 22.

[0070] Furthermore, the segment structure according to this embodiment includes the ring joint structure described above and has a steel shell that constitutes the outer shell of the segment 10. With this configuration, since segment 10 has a steel shell, the elongated holes 22 installed on the inter-ring joint surface 11a are also easy to process as steel material, and the above effects can be achieved at a low cost.

[0071] Furthermore, in this embodiment, the segment ring structure 1 described above is provided, and among the segments 10 constituting the segment ring, the inter-ring joint structure is provided on the inter-ring joint surface 11a of the segment 10 that is in a position where it is likely to open up in the tunnel circumferential direction X1. With this configuration, the aforementioned inter-ring joint structure is provided only near the locations in the tunnel circumferential direction X1 where gaps are likely to occur in the segment joint surface 13a of the segment ring. This configuration allows for cost reduction compared to providing the inter-ring joint structure near all segment joint surfaces 13a.

[0072] As described above, the ring joint structure 1, segment structure, and segment ring structure according to this embodiment can suppress the falling of concrete blocks due to segment damage while maintaining the structural performance of the tunnel.

[0073] (Second Embodiment) As shown in Figures 9 and 10, the inter-ring joint structure 1A according to the second embodiment is configured to have a circumferential guide portion 23 (guide portion) that extends along the curvature of the tunnel circumferential direction X1 on the inter-ring joint surface 11a. The circumferential guide portion 23 extends continuously over the entire length of the inter-ring joint surface 11a in the tunnel circumferential direction X1.

[0074] The circumferential guide portion 23 includes a convex guide 23A provided on one inter-ring joint surface 11a in the tunnel axis direction X2, and a concave guide 23B provided on the other inter-ring joint surface 11a. The convex guide 23A is positioned on the outer and inner sides of the inter-ring joint surface 11a. The concave guide 23B is positioned on the outer and inner sides of the inter-ring joint surface 11a so as to engage with the convex guides 23A on the outer and inner sides, respectively. The convex guide 23A of one segment 10 and the concave guide 23B of the segment 10 adjacent to it in the tunnel axis direction X2 are relatively movable in the tunnel circumferential direction X1 when engaged with each other.

[0075] Furthermore, the circumferential guide portion 23 is not limited to being arranged around the entire circumference of the inter-ring joint surface 11a, but may be provided partially in the tunnel circumferential direction X1. For example, the length of the concave guide 23B in the tunnel circumferential direction X1 can be longer than the length of the convex guide 23A in the tunnel circumferential direction X1 that is partially provided in the tunnel circumferential direction X1. In short, any circumferential guide that can guide one segment 10 and the other segment 10 adjacent to each other in the tunnel axial direction X2 to move relative to each other in the tunnel circumferential direction X1 is sufficient.

[0076] In the inter-ring joint structure 1A of this second embodiment, the circumferential guide portion 23 extends with a curvature equivalent to the curvature of the inter-ring joint surface in the tunnel circumferential direction X1. This facilitates the processing of the inter-ring joint surface 11a of the segment 10, thereby reducing manufacturing costs. Furthermore, in this second embodiment, a configuration in which the segments slide in the tunnel circumferential direction X1 can be easily realized, and the relative movement length of adjacent segments 10 in the tunnel circumferential direction X1 can be made large.

[0077] Furthermore, in this second embodiment, since the circumferential guide portion 23 is continuous in the tunnel circumferential direction X1, the fitting and fine adjustment of the segments 10 can be easily performed during assembly. Therefore, the workability can be improved.

[0078] (Third embodiment) The inter-ring segment structure 1B according to the third embodiment shown in Figure 11 includes a third inter-ring joint 20C in the inter-ring joint 20, which is constrained to move to both sides in the tunnel circumferential direction X1, between the first inter-ring joint 20A and the second inter-ring joint 20B that are adjacent in the tunnel circumferential direction X1. The third inter-ring joint 20C has a male joint 24A, which is made of, for example, a bolt or pin member, and a female joint 24B, which is a circular hole through which the male joint 24A is inserted. The diameter of the circular hole in the female joint 24B is approximately the same as the outer diameter of the male joint 24A.

[0079] In the third embodiment, the third inter-ring joint 20C, which allows displacement of the inter-ring joint 20 in the tunnel circumferential direction X1 near the segment joint 15 and effectively prevents damage to the segment 10, while constraining movement in the tunnel circumferential direction X1, can suppress excessive opening behavior of the segment joint surface 13a.

[0080] (Fourth Embodiment) The inter-ring segment structure 1C according to the fourth embodiment shown in Figure 12 is equipped with a circumferential guide portion 23 and has a configuration in which a plurality of devices 25 that restrain movement in the tunnel circumferential direction X1 are arranged at intervals in the tunnel circumferential direction X1 on the inter-ring joint surface 11a. The devices 25 are positioned along the tunnel circumferential direction X1, at a distance of more than 1 times the radial height H of the segment 10 from the segment joint surface 13a. The devices 25 are positioned at approximately 1 / 2 of the height H in the radial direction of the segment 10.

[0081] In this case, the circumferential guide portion 23 allows for displacement of the inter-ring joint surface 11a in the tunnel circumferential direction X1 near the segment joint, effectively preventing damage to the segment 10, while the device that restrains it in the tunnel circumferential direction X1 can suppress excessive opening behavior of the segment joint surface 13a. The device 25 that restrains it in the tunnel circumferential direction X1 may be mechanical or bolted, and it is desirable that multiple devices be placed on the inter-ring joint surface 11a. Furthermore, the displacement in the tunnel circumferential direction X1 due to the opening of the segment joint surface 13a depends on the opening angle and the segment height H. However, in the case of a continuous circumferential guide section 23, the effect of displacement in the tunnel circumferential direction X1 is high, and the structure is such that the effect of opening easily propagates. Therefore, it is preferable to place the jig 25 that restrains the displacement in the tunnel circumferential direction X1 at a distance from the segment joint surface 13a that is less than 1x the height H of the segment 10.

[0082] Next, examples of actions taken to support the effects of the ring joint structure, segment structure, and segment ring structure according to the embodiments described above will be explained below.

[0083] (Examples) In the example, a simplified beam-spring model was applied to investigate the effect of the circumferential restraining force of the inter-ring joint on the axial force generated in the segment ring. Specifically, as shown in Figures 13(a) and (b), in order to investigate the characteristics of the segment ring alone, a simulation was conducted using a beam-spring model of two rings with segment joints arranged in a staggered pattern under the condition of no ground springs. The segment rings were pulled vertically, and the ring shape of the segment rings was flattened. In Figures 13(a) and (b), the symbol F represents tensile force, the symbol S represents a segment joint, and the symbols R1 and R2 represent inter-ring joints. Symbol R1 corresponds to the first inter-ring joint 20A in the embodiment described above, and symbol R2 corresponds to the second inter-ring joint 20B in the embodiment described above. For inter-ring joints R1 and R2, in the comparative example with circumferential constraint, the radial shear stiffness and circumferential shear stiffness were set to 200 MN / m each, while in the example without circumferential constraint, only the radial shear stiffness was set to 200 MN / m. Here, the shear stiffness of the ring joint was set to 200 MN / m based on "Design of Segment No. 23 in the Tunnel Library" (Japan Society of Civil Engineers).

[0084] Table 1 shows the conditions for the analysis model. As shown in Table 1, all other material parameters were kept the same, the tunnel outer diameter was set to 12.75 m, and the maximum bending strength ratio between the segment joint and the segment body was set to 25%.

[0085] [Table 1]

[0086] Figures 14(a) and (b) show the analysis results using the beam spring model of the embodiment, representing the axial force generated in the segment ring. Figure 14(a) shows the analysis results for a comparative example with circumferential constraint. Figure 14(b) shows the analysis results for an embodiment without circumferential constraint. In Figures 14(a) and (b), the force shown inside the circle (corresponding to the segment ring) is the tensile axial force, and the force shown outside the circle (corresponding to the segment ring) is the compressive axial force.

[0087] Figure 15 shows the analysis results comparing the axial force of the example and the comparative example. In Figure 15, the vertical axis represents the axial force (kN). Figure 16 shows the analysis results comparing the bending moment of the example and the comparative example. In Figure 16, the vertical axis represents the bending moment (kNm). Comparing the tensile axial forces in the regions labeled T1 and T2 (horizontal positions passing through the tunnel center) near segment joints in the segment rings shown in Figures 14(a) and (b), it was found that while the tensile axial force generated in the segment body is concentrated near the segment joint when constrained in the circumferential direction, it was reduced by up to 25% when the circumferential direction is removed, confirming that the risk of concrete damage can be reduced.

[0088] Furthermore, as shown in Figure 16, when comparing the bending moments of the examples and comparative examples, they were equivalent regardless of the presence or absence of circumferential constraint. Therefore, it was confirmed that the splice effect can be achieved even without circumferential constraint, and that the structural performance of the tunnel can be achieved in the same way.

[0089] Although embodiments of the ring joint structure, segment structure, and segment ring structure according to the present invention have been described above, the present invention is not limited to the embodiments described above and can be modified as appropriate without departing from the spirit of the invention.

[0090] For example, the application of the segment ring structure 1 described above is not limited to shield tunnels 100. For instance, it may be applied to ring-shaped structures composed of arc-shaped segments, including the foundation structure for floating offshore wind turbines.

[0091] Furthermore, although this embodiment targets a composite segment as segment 10, it can also be applied to concrete segments.

[0092] Furthermore, the segment ring structure 1 may be arranged in a portion of the tunnel circumferential direction X1 of the segment ring R. In this case, if, for example, the ground strength differs between one cross-sectional area and another in the tunnel cross-section, the segments 10 of the segment ring structure 1 described above can be arranged according to the ground strength of each cross-sectional area within the tunnel circumferential direction X1 of the segment ring R, thereby achieving high load-bearing capacity in the appropriate locations and efficiently demonstrating the above effects.

[0093] Furthermore, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, without departing from the spirit of the present invention. [Explanation of Symbols]

[0094] 1, 1A, 1B, 1C Inter-ring joint structure 10 segments 11. Main girder (ring joint plate) 11a Inter-ring joint surface 13 Joint Plate 13a Segment joint surface 14 Concrete 15-segment joint 20 Ring joints 20A First ring joint 20B Second ring joint 20C Third Ring Joint 21 Fastening bolt (male part) 22 Slotted holes (guide section, through holes) 22a end 22b Positioning locking part 23 Circumferential guide section 25 devices 100 Shield tunnel (shield tunnel ring structure) R Segment Ring X1 Tunnel circumferential direction (circumferential direction) X2 Tunnel axis direction (Segment ring axis direction) X3 Tunnel Radius Direction

Claims

1. A ring joint structure that connects arc-shaped segments, which are linked together in the circumferential direction to form a segment ring, in the axial direction of the segment ring, The aforementioned segment is The pair of segment joint surfaces arranged opposite each other in the circumferential direction, A pair of inter-ring joint surfaces arranged opposite each other in the axial direction of the segment ring, It has a pair of arcuate surfaces arranged along the circumferential direction, The segment joint surface is provided with a segment joint that connects the segments in the circumferential direction. The ring joint surface is provided with ring joints that connect to adjacent segments adjacent in the segment ring axial direction. The segment joint surfaces are arranged alternately in the circumferential direction with other segment joint surfaces of the adjacent segments. Of the ring joints, the first ring joint closest to the segment joint surface in the circumferential direction is connected to the first ring joint in the state immediately after the segment is assembled to the adjacent segment, and is provided so as to be movable on both sides in the circumferential direction relative to the second ring joint arranged on the adjacent segment. A ring joint structure characterized in that at least one of the first ring joint and the second ring joint has a guide portion that guides the other in the circumferential direction.

2. The ring joint has, on the ring joint surface, a third ring joint between the first and second ring joints that are adjacent in the circumferential direction, whose movement in both circumferential directions is constrained. The inter-ring joint structure according to claim 1.

3. The first ring joint is provided along the circumferential direction, within a distance from the segment joint surface to twice the radial height of the segment. The inter-ring joint structure according to claim 1.

4. The aforementioned ring joint has a joint structure in which the male part is inserted into the female part. The ring joint plate is provided with a female part having a through hole or recess into which the male part can be inserted, in at least one of the first ring joint and the second ring joint. The female mold portion is the guide portion, and is composed of an elongated hole in which the circumferential hole diameter is larger than the radial hole diameter. The male part, when inserted into the female part, has a greater circumferential loose fit than the radial loose fit. The inter-ring joint structure according to claim 1.

5. The ring joint plate is provided in both the first ring joint and the second ring joint. The male part is simultaneously penetrated through the through holes in the ring joint plates of the first ring joint and the second ring joint. The inter-ring joint structure according to claim 4.

6. The through hole or recessed hole has a circumferential diameter greater than or equal to the radial diameter + 2 mm × 2. The inter-ring joint structure according to claim 4.

7. The through hole or recessed hole has a positioning locking portion that is radially recessed at the position where the male part is inserted during segment assembly. The inter-ring joint structure according to claim 4.

8. The guide portion is a circumferential guide portion that extends along the circumferential curvature of the inter-ring joint surface. The inter-ring joint structure according to claim 1.

9. The circumferential guide portion extends continuously over the entire circumferential direction of the inter-ring joint surface. The ring joint structure according to claim 8.

10. The circumferential guide portion is provided, A device for restraining movement in the circumferential direction is arranged on the joint surface between the rings. The ring joint structure according to claim 8.

11. The aforementioned device is Along the circumferential direction, the following are positioned at a distance greater than 1 times the radial height of the segment from the segment joint surface: The inter-ring joint structure according to claim 10.

12. A segment structure characterized by comprising the ring joint structure described in any one of claims 1 to 11.

13. A segment ring structure characterized by comprising the inter-ring joint structure described in any one of claims 1 to 11.

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