Segment joint structure

Abstract

To provide segment joint structure capable of enhancing the segment joint strength without complicating the structure.SOLUTION: Since a recess 11a and a protrusion 11b that fit together when main girders 11 of adjacent segments 10 are butted together are provided on a tunnel axial direction end face of the segment 10, the joint strength of the segment 10 in a tunnel radial direction can be enhanced through the fitting of the recess 11a and the protrusion 11b. In this case, since the recess 11a and the protrusion 11b are integrally formed on the main girder 11, there is no need to add separate members, and this has the advantage of not complicating the structure. Furthermore, compared to structure requiring welding of separate members, it has the advantage of higher fatigue strength. Moreover, since the recess 11a and the protrusion 11b are formed to extend continuously in a tunnel circumferential direction, loads applied to the segment 10 in the tunnel radial direction can be distributed in the tunnel circumferential direction, thereby suppressing stress concentration.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a segment joint structure for joining segments for, for example, shield tunnel lining in the tunnel axis direction. [Background technology]

[0002] A conventional shield tunnel construction method is known in which multiple segments formed in an arc shape along the tunnel circumferential direction are joined together in a ring shape along the tunnel circumferential direction, and the joined ring-shaped segments are then joined together in the tunnel axial direction to form a lining. A known segment used in this construction method includes a pair of main girders arranged on both end faces of the segment in the tunnel axial direction, an arc-shaped skin plate arranged on the outer periphery of the segment, and a pair of joint plates arranged on both end faces of the segment in the tunnel circumferential direction, with reinforcing bars and rib steel arranged inside a steel shell made of these steel materials, and the steel shell and filled concrete are integrated (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-210771 Summary of the Invention [Problem to be solved by the invention]

[0004] In shield tunnels, segments may be subjected to high internal pressures and loads in the radial direction of the tunnel, making it necessary to increase the joint strength between segments in the axial direction of the tunnel. However, in conventional segment joint structures, segments are joined only by inter-ring joints installed on the main girders, which means that shear forces between the segments are concentrated at the joints, potentially resulting in insufficient joint strength between segments in the radial direction of the tunnel against high loads. Furthermore, adding additional components to increase joint strength increases the number of components, complicating the structure and increasing costs.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a segment joining structure that can increase the joining strength of the segments without complicating the structure. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a segment joining structure that joins segments formed in an arc shape along the tunnel circumferential direction in the tunnel axis direction, in which plate-like members arranged on the end faces of the segments in the tunnel axis direction are each provided with recesses and protrusions that fit together when the plate-like members of adjacent segments are butted together, and the recesses and protrusions are formed integrally with the plate-like members so as to extend continuously in the tunnel circumferential direction of the segments.

[0007] As a result, the fitting of the recessed and protruding portions increases the joint strength of the segments in the tunnel radial direction. In this case, the recessed and protruding portions are formed integrally with the main girder, so there is no need to add separate components. Furthermore, because the recessed and protruding portions are formed to extend continuously in the tunnel circumferential direction, the load applied to the segments in the tunnel radial direction is dispersed in the tunnel circumferential direction, suppressing stress concentration. [Effects of the Invention]

[0008] According to the present invention, the joining strength of the segments in the tunnel radial direction can be increased, thereby ensuring sufficient joining strength even when subjected to high internal pressure or high load. In this case, there is no need to add additional members, which has the advantage of not complicating the structure and providing higher fatigue strength than a structure in which separate members are welded. Furthermore, the load applied to the segments in the tunnel radial direction can be distributed in the tunnel circumferential direction, suppressing stress concentration, thereby further increasing the joining strength in the tunnel radial direction. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a front view of a segment showing a first embodiment of the present invention; [Figure 2] Bottom view of the segment [Figure 3] Side view of the segment [Figure 4] Front cross section of segment [Figure 5] Enlarged cross-sectional side view of the main part showing the segment joining process [Figure 6] Enlarged cross-sectional side view of the main part showing the joining state of the segments [Figure 7] Enlarged side cross-sectional view of the recessed and protruding portions [Figure 8] 10 is an enlarged side cross-sectional view of a recess and a protrusion, illustrating a second embodiment of the present invention. [Figure 9] An enlarged cross-sectional side view of the recess and protrusion showing the mated state [Figure 10] 10 is an enlarged side cross-sectional view of a recess and a protrusion, illustrating a third embodiment of the present invention. [Figure 11] An enlarged cross-sectional side view of the recess and protrusion showing the mated state [Figure 12] An enlarged cross-sectional side view of the recessed and protruding portions showing the opening state DETAILED DESCRIPTION OF THE INVENTION

[0010] 1 to 7 show a first embodiment of the present invention, which shows a segment joint structure for joining shield tunnel lining segments together in the tunnel axis direction.

[0011] The segment 10 of this embodiment comprises a pair of main girders 11 as plate-like members arranged on both end faces in the axial direction of the tunnel, an arc-shaped skin plate 12 arranged on the outer peripheral surface of the segment 10, and a pair of joint plates 13 arranged on both end faces in the circumferential direction of the tunnel of the segment 10, and is formed by arranging multiple vertical ribs 14 and reinforcing bars (not shown) within the steel shell formed by each main girder 11, skin plate 12 and each joint plate 13, and integrating this steel shell with filled concrete 15.

[0012] Each main girder 11 is made of plate-like steel material spaced apart from one another in the tunnel axis direction and formed in an arc shape along the tunnel circumferential direction. A recess 11a and a protrusion 11b are provided on both end faces of the segment 10 in the tunnel axis direction, and fit together when the main girders 11 of adjacent segments 10 are butted against each other. The recess 11a and the protrusion 11b are formed integrally with the main girder 11 so as to extend continuously in the tunnel circumferential direction of the segment 10 from one longitudinal end to the other.

[0013] The recesses 11a are provided at two locations spaced apart in the radial direction of the tunnel on the outer surface of one of the main girders 11, and are formed so that their cross sections, as viewed from the circumferential direction of the tunnel, are trapezoidal. The protrusions 11b are provided at two locations spaced apart in the radial direction of the tunnel on the outer surface of the other of the main girders 11, and are formed so that their cross sections, as viewed from the circumferential direction of the tunnel, are trapezoidal and can fit into the recesses 11a. In this case, as shown in Figure 7, when the recesses 11a and the protrusions 11b are fitted together, a minute gap S1 (for example, 1 mm) is formed between the bottom surface of the recess 11a and the top surface of the protrusion 11b, and a minute gap S2 (for example, 1.5 mm) is formed between each side surface of the recess 11a and each side surface of the protrusion 11b.

[0014] 5 and 6, a pair of watertight rubber members 16 are provided between the main girders 11 of adjacent segments 10, extending continuously in the circumferential direction of the tunnel. In this case, one watertight rubber member 16 is disposed between one end of the main girder 11 in the tunnel radial direction and the recessed portion 11a and the protruding portion 11b, and the other watertight rubber member 16 is disposed between the other end of the main girder 11 in the tunnel radial direction and the recessed portion 11a and the protruding portion 11b. In addition, grooves 11c into which the watertight rubber members 16 engage are provided on the outer surface of each main girder 11.

[0015] The skin plate 12 is made of a thin steel plate, and both ends in the width direction (tunnel axis direction) are welded to the outer peripheral ends of each main girder 11.

[0016] Each joint plate 13 is made of a long, flat steel plate, and both ends of its longitudinal direction (tunnel axis direction) are welded to the ends of each main girder 11, and one end of its transverse direction (tunnel diameter direction) is welded to the end of the skin plate 12.

[0017] Each vertical rib 14 is made of a horizontally long, flat steel plate, and is formed so that its dimension in the short side (tunnel diameter direction) is smaller than the dimension in the short side direction of the joint plate 13. Each vertical rib 14 is arranged at intervals around the tunnel so that its thickness direction is the tunnel circumferential direction, and both ends of its length are welded to the inside surface of each main girder 11.

[0018] The fill concrete 15 is poured in a factory or the like into the steel shell formed by the main girders 11, skin plates 12, and joint plates 13, and its inner surface is formed in an arc shape along the circumferential direction of the tunnel. In this case, the inner side of the fill concrete 15 is formed so that it protrudes slightly inward in the radial direction of the tunnel beyond the inner circumferential ends of the main girders 11.

[0019] In addition, the segments 10 are equipped with joints for joining the segments 10 together in the tunnel circumferential direction, including male joint portions 17 provided at one end or the other end of each joint plate 13 in the width direction, and female joint portions 18 provided at the other end or the other end of the joint plate 13 in the width direction, and the male joint portions 17 and female joint portions 18 are arranged on opposite sides of the joint plates 13 in the width direction, in the joint plates 13 at one end of the segments 10 in the tunnel axis direction and the joint plates 13 at the other end.

[0020] The male joint 17 consists of a plate-shaped engaging member 17a whose one end protrudes from the joint plate 13 in the tunnel circumferential direction, and a protrusion 17b provided at the tip of the engaging member 17a so as to protrude in the tunnel radial direction. The protrusion 17b is formed by welding a steel rod to both sides of the engaging member 17a in the thickness direction. The engaging member 17a penetrates the joint plate 13 vertically so that its thickness direction is in the tunnel radial direction, and is joined to an anchor reinforcing bar (not shown) embedded in the filled concrete 15.

[0021] The female joint 18 comprises an engagement hole 18a that engages with the engagement member 17a of the male joint 17 and a dam plate 18b provided on the inner surface of the joint plate 13 to surround the engagement hole 18a, with the dam plate 18b forming a space for inserting the engagement member 17a of the male joint 17. The engagement hole 18a is formed as an elongated hole extending in the tunnel axis direction, with one longitudinal end opening at the end of the joint plate 13 and the opening edge of the engagement hole 18a being tapered. The dam plate 18b has a U-shaped cross section and is joined to an anchor reinforcing bar (not shown) embedded in the filled concrete 15. The end of the main girder 11 is provided with a notch 11d for inserting the engagement member 17a of the male joint 17 into the dam plate 18b.

[0022] Furthermore, the segments 10 are provided with joints for joining the segments 10 together in the tunnel axis direction, namely, a male joint 19 attached to one main girder 11 and a female joint 20 attached to the other main girder 11, and the male joint 19 and female joint 20 are provided at intervals at multiple locations in the tunnel axis direction.

[0023] The male joint 19 consists of a pin bolt with sawtooth (not shown) formed on its outer surface, and is arranged to pass through one of the main girders 11 and extend outward.

[0024] The female joint 20 consists of a cylindrical member into which the male joint 19 is inserted, and is fixed to the inner surface of the other main girder 11. As shown in Figures 5 and 6, when the male joint 19 is inserted through an insertion hole 11e provided in the other main girder 11, a wedge (not shown) provided inside the female joint 20 is pushed apart by the male joint 19, and the wedge bites into the sawtooth of the male joint 19 to maintain pull-out strength against the pull-out force. In this case, the tensile force acting on the male joint 19 and female joint 20 is transmitted to the main girder 11 and the longitudinal rib 14.

[0025] When joining segments 10 configured as described above in the circumferential direction of the tunnel, one of the segments 10 to be joined in the circumferential direction of the tunnel is moved in the axial direction of the tunnel relative to the other segment 10 while engaging the male joint 17 and female joint 18 of the joint plate 13. At this time, the engaging member 17a of the male joint 17 is inserted into the engaging hole 18a from the axial direction of the tunnel, and the protrusion 17b located inside the dam plate 18b engages with the inner surface of the joint plate 13, connecting the segments 10 to each other by the male joint 17 and the female joint 18. As a result, a plurality of segments 10 are joined in a ring shape, although this is not shown.

[0026] Furthermore, when joining segments 10 joined in a ring shape in the tunnel axis direction, the segments 10 are butted together in the tunnel axis direction to join the male joints 19 and female joints 20 of the main girders 11. At this time, as shown in Figures 5 and 4, the recesses 11a and protrusions 11b of the opposing main girders 11 fit together, and the watertight rubbers 16 are placed between the main girders 11 while engaging with the grooves 11c, and the watertight rubbers 16 seal the space between the butted main girders 11.

[0027] In segments 10 joined in the tunnel axis direction, if a shear force occurs between the main girders 11 of each segment 10 due to a load in the tunnel radial direction, the recesses 11a and protrusions 11b of the main girders 11 fit together, so the shear force is not applied to the male joints 19 and female joints 20 of the main girders 11, and the strong fit between the main girders 11 by the recesses 11a and protrusions 11b ensures sufficient joint strength of the segments against high loads. In this case, because the recesses 11a and protrusions 11b are formed so as to extend continuously in the tunnel circumferential direction, the load in the tunnel radial direction applied to the segments 10 is dispersed in the tunnel circumferential direction, and stress due to the load does not concentrate in one place.

[0028] Thus, according to this embodiment, recesses 11a and protrusions 11b are provided on the tunnel axis direction end faces of the segments 10, which fit together by butting the main girders 11 of adjacent segments 10 together.Therefore, the fitting of the recesses 11a and protrusions 11b can increase the joint strength of the segments 10 in the tunnel radial direction, and sufficient joint strength can be obtained even when subjected to high internal pressure or high load.

[0029] In this case, the recessed portions 11a and the protruding portions 11b are formed integrally with the main girder 11, which has the advantage of eliminating the need to add separate members and thus preventing the structure from becoming more complex. Another advantage is that fatigue strength is higher than in a structure in which separate members are welded. Furthermore, because the recessed portions 11a and the protruding portions 11b are formed to extend continuously in the tunnel circumferential direction, the load applied to the segment 10 in the tunnel radial direction can be dispersed in the tunnel circumferential direction, suppressing stress concentration and further increasing the joint strength in the tunnel radial direction.

[0030] Furthermore, since the recessed portion 11a and the protruding portion 11b are formed to have a trapezoidal cross section, the recessed portion 11a and the protruding portion 11b can be guided by the tapered side surfaces and easily fitted together, thereby improving workability during installation.

[0031] Furthermore, a pair of water-stopping rubbers 16 are provided at intervals in the tunnel radial direction between the main girders 11 of adjacent segments 10, extending continuously in the tunnel circumferential direction along the recessed portions 11a and protruding portions 11b, and the recessed portions 11a and protruding portions 11b are arranged between each of the water-stopping rubbers 16, so that the intrusion of external water into the recessed portions 11a and protruding portions 11b from the tunnel radial direction can be prevented by each of the water-stopping rubbers 16. This makes it possible to suppress deterioration of the recessed portions 11a and protruding portions 11b over time and improve the long-term durability of the shield tunnel.

[0032] In the above embodiment, male joint portions 17 and female joint portions 18 are used as joints that join segments 10 together in the tunnel circumferential direction, and male joints 19 and female joints 20 are used as joints that join segments 10 together in the tunnel axial direction, but other types of joints may also be used.

[0033] 8 and 9 show a second embodiment of the present invention, in which the same components as those in the first embodiment are denoted by the same reference numerals.

[0034] In this embodiment, each of the main girders 11 that abut against each other is provided with one recess 11e and one protrusion 11f, and similarly to the previous embodiment, the recess 11e and the protrusion 11f are formed integrally with the main girders 11 so as to extend continuously from one longitudinal end to the other end of the main girders 11 in the circumferential direction of the tunnel of the segment 10. In addition, the recess 11e of one main girder 11 is formed to fit into the protrusion 11f of the other main girder 11, and the protrusion 11f of one main girder 11 is formed to fit into the recess 11e of the other main girder 11.

[0035] The recess 11e and the protrusion 11f are each formed so that their cross sections, as viewed from the tunnel circumferential direction, are trapezoidal, and are formed so that they are continuous with each other in the tunnel radial direction. In this case, the recess 11e is formed so as to be concave by a predetermined depth A1 with respect to the outer surface 11g of the main girder 11, and the protrusion 11f is formed so as to be convex by a predetermined height A2 with respect to the outer surface 11g of the main girder 11. Furthermore, when the recess 11e and the protrusion 11f are fitted together, a minute gap S1 (e.g., 1 mm) is formed between the bottom surface of the recess 11e and the top surface of the protrusion 11f, and a minute gap S2 (e.g., 1.5 mm) is formed between each side surface of the recess 11e and each side surface of the protrusion 11f.

[0036] As a result, when the main girders 11 are butted together as shown in Figure 9, the recesses 11e and protrusions 11f of each main girder 11 fit together, and even if shear force occurs between the main girders 11 of each segment 10 due to a load in the tunnel radial direction, the fitting recesses 11e and protrusions 11f abut in the tunnel radial direction, and the strong fit between the main girders 11 ensures sufficient joint strength of the segments against high loads.

[0037] In this case, the recess 11e is formed to be concave relative to the outer surface 11g of the main girder 11, and the protrusion 11f is formed to be convex relative to the outer surface 11g of the main girder 11, so that the fitting height B of the recess 11e and the protrusion 11f on the continuous surface 11h that continues from the recess 11e to the protrusion 11f (the length in the tunnel axis direction of the abutment surface (part C in the figure) of the recess 11e and the protrusion 11f) can be made twice the height A2 of the protrusion 11f. As a result, even in cases where it is difficult to integrally form recesses and protrusions with large depths or heights, as in rolling, for example, the fitting height B of the recess 11e and the protrusion 11f can be sufficiently ensured in this embodiment, which is extremely advantageous in terms of manufacturing.

[0038] 10 to 12 show a third embodiment of the present invention, in which the same components as those in the first and second embodiments are denoted by the same reference numerals.

[0039] In this embodiment, each main girder 11 is provided with a recess 11e and a protrusion 11f equivalent to those in the second embodiment, and continuous surfaces 11h extending from the recess 11e to the protrusion 11f are formed on one side of the tunnel radial direction and the other side. That is, a protrusion 11f is provided on each side of the recess 11e in the width direction (tunnel radial direction) of one main girder 11 (left side in the figure), and a recess 11e is provided on each side of the protrusion 11f in the width direction (tunnel radial direction) of the other main girder 11 (right side in the figure). Also, as in the second embodiment, the recess 11e is formed to be recessed by a predetermined depth A1 relative to the outer surface 11g of the main girder 11, and the protrusion 11f is formed to be protruded by a predetermined height A2 relative to the outer surface 11g of the main girder 11. Furthermore, when the recess 11e and the protrusion 11f are fitted together, a minute gap S1 (e.g., 1 mm) is formed between the bottom surface of the recess 11e and the top surface of the protrusion 11f, and a minute gap S2 (e.g., 1.5 mm) is formed between each side surface of the recess 11e and each side surface of the protrusion 11f.

[0040] As a result, when the main girders 11 are butted together as shown in Figure 11, the recesses 11e and protrusions 11f of each main girder 11 fit together, and even if shear force is generated between the main girders 11 of each segment 10 due to a load in the tunnel radial direction, the fitting recesses 11e and protrusions 11f abut in the tunnel radial direction, and the strong fit between the main girders 11 ensures sufficient joint strength of the segments against high loads.

[0041] In this case, even if gaps occur between each main girder 11 as shown in Figure 12, at the abutment surface of the continuous surface 11h where the recesses 11e and protrusions 11f are continuous (part D in the figure), a sufficient fitting height B can be secured in either direction along the tunnel diameter, compared to the abutment surface where the recesses 11e and protrusions 11f are not continuous (part E in the figure), and the fitting strength against shear forces between each main girder 11 can be further increased.

[0042] It should be noted that the above-described embodiments are examples of the present invention, and the present invention is not limited to those described in these embodiments. [Explanation of symbols]

[0043] 10...segment, 11...main girder, 11a...recess, 11b...convex portion, 11e...recess, 11f...convex portion, 11g...outer surface, 11h...continuous surface, 12...skin plate, 13...joint plate, 14...longitudinal rib, 15...filled concrete, 16...water-stop rubber, 17...male side joint, 18...female side joint, 19...male side joint, 20...female side joint.

Claims

1. In a segment joint structure in which segments formed in an arc shape along the tunnel circumferential direction are joined in the tunnel axial direction, a recess and a protrusion that are provided on each of the plate-like members arranged on the end faces of the segments in the tunnel axis direction and that fit together when the plate-like members of adjacent segments are butted against each other; The recessed and protruding portions are formed integrally with the plate-like member so as to extend continuously in the tunnel circumferential direction of the segment. A segment joint structure characterized by the above.

2. The recessed and protruding portions are formed so that the cross section viewed from the circumferential direction of the tunnel is trapezoidal.

2. The segment joint structure according to claim 1.

3. At least one recess and one protrusion are provided on the plate-like member, and the recess and the protrusion are formed so as to be continuous in the tunnel radial direction.

2. The segment joint structure according to claim 1.

4. The recessed portion is formed to a predetermined depth relative to the outer surface of the plate-like member, and the protruding portion is formed to a predetermined height relative to the outer surface of the plate-like member.

4. The segment joint structure according to claim 3.

5. The recessed portion and the protruding portion are formed so that there is at least one continuous surface extending from the recessed portion to the protruding portion on one side and the other side of the tunnel radial direction.

5. The segment joint structure according to claim 4.

6. a pair of sealing materials are provided between the plate-like members of adjacent segments at intervals in the tunnel radial direction, the sealing materials extending continuously in the tunnel circumferential direction along the recessed and protruding portions; The recessed and protruding portions are disposed between the sealing materials.

2. The segment joint structure according to claim 1.

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