JP4920623B2 - Concrete filled steel segment - Google Patents

Description

  The present invention relates to a concrete-filled steel segment in which concrete is packed inside a steel shell, and particularly, when a reaction force for propulsion during shield machine excavation is applied to the segment, cracking of the concrete near the main girder is generated. For preventable concrete filled steel segments.

  A type of segment that forms cylindrical structures such as shield tunnels is known as a concrete-filled steel segment in which concrete is packed inside a steel shell with a main girder, skin plate, joint plate, and vertical ribs. Yes. Such a concrete-filled steel segment is resistant to concrete against the compressive load due to jack thrust during propulsion of the shield machine, and to the steel shell and concrete against load such as earth water pressure when completed. High strength and high rigidity can be obtained.

  FIG. 17 shows a configuration example of the concrete-filled steel segment 7. The steel segment 7 is connected with a plurality of vertical ribs 72 arranged between the main girders 71 at predetermined intervals, and the end portions of the main girders 71 are joined with a joint plate 73. A steel shell 70 is formed by connecting a skin plate 74 to the outside of the plate 73. Inside the steel shell 70 is filled concrete 75.

  By the way, when actually manufacturing such a concrete-filled steel segment 7, the main girder 71, the longitudinal rib 72, the joint plate 73, and the skin plate 74 are fixed to each other by welding to each other. The shell 70 will be formed. At this time, the steel shell 70 is actually deformed by thermal distortion due to welding. 18A is a side sectional view of the crossing position (B portion) between the main beam 71 and the vertical rib 72 shown in FIG. 17, and FIG. 18B is a view of the vertical rib 72b adjacent to the vertical rib 72a. The side sectional view in the contact part (I part) of the main girder 71 of the intermediate part and concrete is shown, and the contact state with the segment of the adjacent ring at the time of segment assembly is shown.

  When actually forming the steel shell 70, for example, when the longitudinal rib 72 and the main beam 71 are welded, thermal distortion due to thermal contraction occurs. However, in the portion B, as shown in FIG. The deformation is constrained by the skin plate 74 and the vertical rib 72 welded thereto. On the other hand, in the portion I, since the outer peripheral surface side is welded to the skin plate 74 as shown by the dotted line in FIG. 18 (b), deformation due to thermal strain is restrained, but the inner air surface side is the skin plate. Since 74 does not exist, deformation occurs such that the inner surface of the main beam 71 is recessed as shown by a two-dot chain line in FIG.

  FIG. 19 schematically shows a planar form when connecting a plurality of concrete-filled steel segments 7 in the tunnel axial direction C, and the segments 7 (7a, 7b, 7c) joined and assembled in a staggered manner. ) As viewed from the inside of the tunnel. The main girder 71 is configured to be connected to the vertical rib 72, the joint plate 73, and the skin plate 74 by welding. In FIG. 19, a state in which the deformation of the main girder 71 on the inner surface side of the tunnel due to thermal strain caused by welding of the longitudinal rib 72 and the joint plate 73 and the main girder 71 is a wavy curve is shown. Due to the thermal strain of welding, the inner girder 71 of the main girder 71 is deformed so as to be recessed, particularly in the I portion. Therefore, the main girders 71a, 71b, 71c of the segments 7a, 7b, 7c arranged adjacent to each other in the tunnel axis direction C. They are arranged so that they are in contact with each other.

  For this reason, as shown in FIG. 18, when the concrete filled steel segments 7 in the state where the main girder 71 is deformed are connected to each other in the axial direction C, the deformation of the main girder 71 causes the surfaces to face each other. The adjacent main girders 71 that should be brought into contact are in line contact with each other through the B portion. Further, there may be point contact depending on the processing accuracy. And when jack force is loaded when connecting between the steel segments 7 in the axial direction C, the concrete 75 and the main girder 71 in the vicinity of the inner space side end face of the main girder 71 of the B cross section which is point-contacted or line-contacted Stress concentration D is generated at the contact portion, and as a result, cracks 76 and chips are generated in the filled concrete 75. Further, if the steel segment 7 is connected in the axial direction C under such a state where the stress concentration D occurs, the stress distribution in the tunnel becomes non-uniform and the proof stress of the entire tunnel is reduced. Problems can arise.

  Although not illustrated, when the main girder 71 cut out from the steel plate is bent, the inner girder 71 is deformed so that the inner circumferential side of the tunnel is thicker than the outer circumferential side of the tunnel of the main girder 71. In this case, the effect of the vicinity of the end face on the sky side of the main girder 71 in the tunnel may be promoted.

  20 and 21, when the main girder 8 is composed of the web 81, the inner air surface side flange 82a, and the outer peripheral surface side flange 82b, the main girder 8 and the vertical rib 83 are joined. The deformation of the main beam 8 is restrained by the longitudinal rib 83 and the skin plate 84 welded to the main beam 8 via the welding region 88 at the region (B ′ portion). On the other hand, the flange 82b on the outer peripheral surface side is restrained by the skin plate 84 at the contact surface H ′ portion of the main girder 8 and the concrete 85 in the middle between the B ′ portion and the cross section B ′ portion. As shown in the two-dot chain line in (b), the flange 82a on the inner air surface side is deformed, and when the jack thrust during the shield machine excavation is applied, it is in the vicinity thereof as shown in FIG. 21 (a). Stress concentration D occurs in the filling concrete 85. As a result, a crack 86 or the like is generated from the location where the stress concentration D occurs. It should be noted that the above-described problem is that there is no flange 82b on the outer peripheral surface side, and welding is performed even when the flange 82a on the inner peripheral surface side, the web 81, the skin plate 84, and the vertical rib 83 are joined by welding via the welding portion 88. The welding to the part 88 causes deformation due to thermal strain, and the same problem occurs.

  Further, when the flange 82a is provided on the inner air surface side, even if the deformation due to the thermal distortion of the welded portion 88 is corrected regardless of the presence or absence of the flange 82b on the outer peripheral surface side, the deformation can be prevented. When stress due to compressive force in the tunnel axial direction C due to jack thrust at the time of excavation of the shield machine is applied, stress concentration occurs in the concrete in contact with the end surface 82c of the inner peripheral surface side flange 82a, particularly at the corner of the end surface 82c. Therefore, cracks may occur.

  In order to prevent the occurrence of cracks in such a concrete segment, for example, a technique disclosed in Patent Document 1 has been proposed.

  That is, as shown in FIG. 22, the disclosed technique in Patent Document 1 includes a connection surface 95a formed at both ends in the axial direction and a connection surface 95b formed at both ends in the circumferential direction. A stress distribution plate 91 made of a material having higher ductility than concrete such as concrete is provided on the outer peripheral side of the connecting surface 95 a in the axial direction of the segment body 95. The stress distribution plate 91 has a radial width that is about half of the radial width of the segment body 95. The stress distribution plate 91 is substantially the same as the curvature of the segment body 95 and is formed to be curved.

In the disclosed technique of Patent Document 1, even when a concentrated force acts on the end surface of the segment body, the stress dispersion plate 91 itself is deformed to disperse the stress, thereby preventing the segment body from being cracked or chipped. It is shown that it will be possible.
JP 2004-353393 A

  However, since the disclosed technology disclosed in Patent Document 1 has a configuration in which the stress distribution plate 91 such as a steel plate is pasted to the outer surface of the segment, the stress distribution plate 91 may drop off or have wrinkles during handling. In some cases. In such a case, there is a problem in that the original function of the stress distribution plate 91 cannot be exhibited, and cracking of the segments cannot be prevented. In addition, since the stress distribution plate resists the impact load during handling, etc., a material harder than concrete, such as a steel plate, is used, so the above stress is applied to the compressive force in the tunnel axial direction when jack thrust is applied. There is a problem that cracks are easily generated in the concrete due to the stress concentration generated in the concrete near the corner of the dispersion plate.

  In addition, the segments that are less likely to crack due to external loads due to contact during handling than the concrete segment include skin plates (often formed only on the outer surface of the tunnel), main girders, joint plates and segments. A concrete-filled steel segment, etc., in which concrete is filled in a steel shell assembled by welding longitudinal ribs therein, has already been used.

  In the above concrete-filled steel segment, the concrete placement height is to ensure the corrosion resistance of the steel material on the inner surface of the segment tunnel, that is, the steel material such as main girders, joint plate vertical ribs, and skin plates, and the inner surface of the tunnel when completed. In order to ensure smoothness, etc., it is driven to a position higher than the main girder, joint plate, and vertical rib.

  However, in such a configuration, although there is an effect of preventing cracks during handling such as segment transportation and assembly, the corners of the main girder steel plate due to the compressive force in the tunnel axial direction when the jack thrust acts during shield machine excavation The main girder's flange steel plate corner, especially the main girder, is deformed due to thermal distortion caused by welding, causing stress concentration in the concrete near the inner circumferential surface of the main girder tunnel at the welded part of the main girder and joint plate. There was a problem that concrete was peeled off due to cracks in the nearby concrete and cracks.

  That is, in the concrete segment and the concrete-filled steel segment, the stress distribution plate having higher ductility than the steel material or concrete is in contact with the concrete, and the compressive force in the tunnel axial direction during jack thrust action causes the steel material and the stress distribution plate to It has a configuration in which cracks are generated in the concrete due to stress concentration generated in the concrete in the vicinity of the corner, and a configuration to solve this has been desired conventionally.

  Therefore, the present invention has been devised in view of the above-described problems, and is a concrete filling that can firmly prevent the occurrence of cracks in the concrete near the inner surface of the main girder due to the thrust of the jack when propelling the shield machine. The aim is to provide a steel segment.

  In order to solve the above-described problem, the present inventor, when filling concrete inside the steel shell, sets the height of the concrete to be equal to or less than the height of the outer main girder at least on the contact surface to the outer main girder. It was found that by adjusting to, cracks in the concrete near the main girder can be prevented more firmly.

That is, the concrete-filled steel segment according to claim 1 includes an outer main girder that forms both side surfaces, a skin plate that covers at least an outer peripheral surface side between the outer main girders, and an end portion of the outer main girder. In a concrete-filled steel segment in which concrete is packed inside a steel shell having a joint plate that connects between them and a vertical rib that connects between the outer main girders, the outer main girder includes a web and the web The steel shell has a middle main girder arranged in parallel with the outer main girder between the outer main girders, and the height of the concrete is , At least the contact surface to the outer main girder is lower than the inner lower surface of the steel shell of the flange formed on the inner air surface side, and the contact surface to the middle main girder is not more than the height of the middle main girder, The longitudinal rib and / or the joint plate; The outer main girder and / or the middle main girder are below the height of the outer main girder and / or the middle main girder and are in contact with the outer main girder and / or the middle main girder. Other than the above, the outer main girder and / or the middle main girder are filled over the height .

The concrete-filled steel segment according to claim 2 is the invention according to claim 1, wherein the height of the concrete is at least the outer main girder and / or the contact surface to the middle main girder. And / or 1-5 mm lower than the height of the middle main beam .

  In the present invention configured as described above, the concrete is not in contact with the inner surface of the main girder, that is, the inner surface of the tunnel. Therefore, even when wavy deformation occurs on the tunnel inner surface side of the main girder, the concrete is not in contact with the steel plate corner on the tunnel inner surface side, or the steel plate corner on the tunnel inner surface side is in contact with the concrete. Since an elastic material having a lower elastic modulus than concrete is interposed in the vicinity including the surface, stress concentration on the concrete is eliminated. As a result, it is possible to prevent stress concentration from occurring on the concrete that contacts the inner surface of the tunnel of the main girder as in the prior art, thereby preventing cracks and chips from occurring in the concrete. Is possible.

  In the present invention, since the segments can be connected in the axial direction E in a state where there is no stress concentration at the contact surface between the concrete and the main girder, the stress distribution in the tunnel becomes uniform and the proof stress of the entire tunnel Can be improved.

   Further, in the present invention, there is no risk of dropping or the like during handling and stress concentration of the concrete near the corners of the stress dispersion plate, which has occurred when a stress dispersion plate such as a steel plate is provided.

  Hereinafter, as a best mode for carrying out the present invention, a concrete filled steel segment in which concrete is packed inside a steel shell will be described in detail with reference to the drawings.

  The concrete-filled steel segment that is the subject of the present invention is a steel segment in which steel-filled concrete is filled in a steel shell assembled by manufacturing steel plates, and a synthetic segment in which concrete is filled in the steel shell. is there.

  Hereinafter, as a best mode for carrying out the present invention, a segment connecting structure for connecting a plurality of segments in a staggered manner will be described in detail with reference to the drawings.

  FIG. 1 shows an example of a shield tunnel 3 to which a concrete-filled steel segment according to the present invention is applied. As shown in FIG. 1, the shield tunnel 3 is constructed by assembling a lining body in which a plurality of arc-shaped segments 4 are connected in a ring shape at a segment joint portion 65 on the inner surface of the tunnel. In this shield tunnel, in order to improve the structural strength and rigidity of the shield tunnel 3 as a whole, the segments 4 are connected in a staggered manner between the adjacent segment rings, and the segment rings are connected in the axial direction E. , Making this connection more robust. In order to actually form the shield tunnel 3, concrete may be cast at the bottom to form a flat floor f.

  As shown in FIG. 2, the segment 4 includes two outer main girds 11 that form both side surfaces, a skin plate 12 that covers at least the outer peripheral surface between the outer main girds 11, and the end of the outer main girder 11. And a steel plate 10 having vertical ribs 14 provided between the outer main beams 11. A bolt hole 98 for connecting segments adjacent in the circumferential direction and the axial direction is provided around the steel shell. The steel shell 10 is filled with concrete as will be described later.

  The outer main girder 11 is formed in a shape divided in the circumferential direction of the segment ring 2, and has a shape curved with a predetermined curvature. This outer main girder 11 is obtained by processing a steel plate. The outer main girder 11 may be formed with bolt insertion holes and joints (not shown) for connecting with other segments 4 adjacent in the axial direction at a predetermined pitch.

  The joint plate 13 extends in a substantially vertical direction with respect to the two outer main girders 11, is processed in advance to a length that allows connection between the ends of the outer main girds 11, and is fixed by welding. The joint plate 13 is provided with a bolt insertion hole 21 for constituting a segment ring by connecting with another segment 4 adjacent in the circumferential direction.

  The skin plate 12 is fixed to the outer main girder 11, the joint plate 13, and the vertical rib 14 by welding. This skin plate 12 forms the outer peripheral side steel plate of the segment ring, and is configured in a shape curved into a cylindrical peripheral surface shape.

  The vertical ribs 14 are arranged with a predetermined interval between the outer main beams 11. The vertical ribs 14 are arranged in a direction substantially parallel to the joint plate 13. The vertical ribs 14 are fixed to the outer main beam 11 and the skin plate 12 by welding. In the example shown in FIG. 2, the height of the vertical rib 14 is set to be lower than the outer main girder 11 and the joint plate 13, but is not limited to this, and is substantially the same. You may make it comprise so that it may become height.

  FIG. 3 shows a state in which concrete 23 is packed in the steel shell 10 having the above-described configuration. FIG. 4 shows a cross section taken along line FF ′ in FIG. Incidentally, this FF ′ cross section shows the configuration of the cross section along the position where the vertical rib 14 is provided, but if this FF ′ cross section is at a position separated from the vertical rib 14, In FIG. 4, the configuration of the vertical ribs 14 is omitted.

  The concrete 23 is poured from the inner surface of the steel shell 10 and is solidified to be filled in the steel shell 10. In addition, bolt boxes 99 are formed for bolting with other segments adjacent in the tunnel axial direction and the circumferential direction. At this time, as shown in FIG. 4, the height of the concrete 23 to be filled from the skin plate 12 is h1, and the height of the concrete 23 at the contact surface 11a with the outer main girder 11 is h2. The height of the outer main girder 11 is h3. At this time, it is assumed that at least the height h2 of the concrete 23 is configured to be equal to or less than the height h3 of the outer main beam 11. That is, the tunnel inner surface side of the contact surface 11a of the outer main girder 11 in the concrete 23 is in a so-called chamfered state. Incidentally, as a form of this chamfering, as shown in FIG. 4, it may be configured to be inclined obliquely with respect to the substantially vertical direction in which the outer main girder 11 is erected. Further, as a form of this chamfering, for example, as shown in FIG. 5, a horizontal plane 23a extending from the contact surface 11a of the outer main girder 11 toward the inside of the segment in the horizontal direction and inclined upward from the horizontal plane 23a. The concrete 23 may be filled so that the inclined surface 23b is formed. As a result, it is possible to create a state in which the concrete 23 is not in contact with the tunnel inner surface side corner portion 11 b of the outer main girder 11.

  The present invention having such a configuration has the following effects. When assembling the segment having the above-described configuration, the outer main girder 11 can be welded to the vertical rib 14, the joint plate 13, and the skin plate 12 and fixed to each other to be a constituent element of the steel shell 10. At this time, the steel shell 10 is actually deformed by thermal distortion due to welding. This state will be described with reference to FIGS. 6A and 6C are cross-sectional views taken along line FF ′ in FIG. 2 in which concrete is filled, that is, the cross-sectional view taken along line FF ′ in FIG. The girder 11 and the skin plate 12 are welded. On the other hand, FIGS. 6B and 6D show a state in which the G-G ′ section in the state in which the concrete is filled in FIG. 2, that is, the G-G ′ section in FIG. 3 is deformed. 6 (a) and 6 (b) correspond to the chamfered form shown in FIG. 4, and FIGS. 6 (c) and 6 (d) correspond to the chamfered form shown in FIG. is there.

  In the FF ′ cross section shown in FIGS. 6A and 6C, the outer main girder 11 tends to be deformed by thermal strain caused by welding to the welded portion 108, but the deformation is restricted by the skin plate 12 and the vertical rib 14. Therefore, the deformation of the outer main beam 11 is very small.

  On the other hand, in the GG ′ cross section shown in FIGS. 6B and 6D, the inner surface of the outer main girder 11 is welded to the outer main girder 11 and the vertical rib 14 in the FF ′ cross section. The outer main girder 11 undergoes out-of-plane deformation inside the segment due to the thermal strain caused by. Incidentally, in FIGS. 6B and 6D, the state before welding of the outer main girder 11 is indicated by a dotted line, and the state after welding is indicated by a solid line. On the other hand, since the skin plate 12 is coupled to the outer peripheral surface side of the tunnel, deformation based on thermal strain is restricted. Accordingly, as shown in FIGS. 6B and 6D, only the tunnel inner surface side of the outer main beam 11 is deformed to the inside of the segment.

  However, in the present invention, the concrete 23 is not in contact with the tunnel inner surface side corner portion 11b of the outer main beam 11 on the tunnel inner surface side. For this reason, even when the outer main girder 11 is deformed out of the plane, since the concrete 23 is not in contact with the tunnel inner surface side corner portion 11b on the inner surface side of the tunnel, jack thrust at the time of excavation of the shield machine is applied. In this case, in the vicinity of the FF ′ cross section, the outer main girder 11 and the vertical rib 14 are in surface contact with the concrete 23. At this time, the tunnel inner side corner 11b of the outer main girder 11 does not contact with concrete. As a result, it is possible to prevent stress concentration from occurring on the concrete 23 that is in contact with the inner surface of the tunnel of the outer main girder as in the prior art. It becomes possible to prevent.

  In the present invention, the segment 4 can be connected in the axial direction E in a state where there is no stress concentration on the contact surface 11a between the concrete 23 and the outer main girder 11, so that the stress distribution in the tunnel becomes uniform. The proof stress of the whole tunnel can be improved.

  Furthermore, in the present invention, it is not necessary to provide a special configuration such as a stress dispersion plate or the like for dispersing the stress, so that the manufacturing labor can be reduced and the manufacturing cost can be reduced. In addition, there is no risk of falling off during handling or stress concentration of the concrete near the corners of the stress distribution plate, which occurs when a stress distribution plate such as a steel plate is provided.

  In addition, when a jack thrust is applied as the shield tunnel is dug, the load based on the jack thrust that is a source of stress concentration at the contact surface 11a between the concrete 23 and the outer main girder 11 generated in the prior art is so large. It is not a thing. For this reason, even if the concrete 23 is not in contact with the corner portion 11b on the tunnel inner surface side of the outer main girder 11 as in the present invention, and the structure cannot bear the load at the location, the load based on the jack thrust described above. Since it is not so large in itself, no particular inconvenience actually occurs.

  In the present invention, it is required that the height h2 of the concrete is configured to be equal to or less than the height h3 of the outer main girder 11. However, in order to surely achieve the above-described effect, h2 Is preferably about 1 to 5 mm lower than h3. Thereby, even when a wavy deformation occurs in the main girder 11 due to thermal strain, stress concentration occurs on the concrete 23 in which the height h2 is set to be lower by about 1 to 5 mm than the corner portion 11b on the tunnel inner surface side. Without generating, it is possible to more effectively reduce the occurrence of cracks and the like.

  FIG. 7 shows a form in which a middle main girder 18 extended in the circumferential direction at the center of the steel shell 10 is provided. In FIG. 7, the same components and members as those in FIG. 2 described above are denoted by the same reference numerals, and the following description is omitted. The middle main girder 18 is arranged in parallel with the outer main girder 11 between the outer main girder 11. Like the outer main beam 11, the middle main beam 18 is formed in a shape divided in the circumferential direction of the segment ring 2, and has a shape curved with a predetermined curvature.

  FIG. 8 shows a state in which the steel shell 10 provided with the middle main girder 18 is filled with concrete 23. The height of the concrete 23 to be filled from the skin plate 12 is h1, and the height at the contact surface 18a with the middle main girder 18 of the concrete 23 is h4. The height of the middle main girder 18 is h5. At this time, it is assumed that the height h4 of the concrete 23 is configured to be at least the height h5 of the middle main girder 18 or less. That is, the upper end of the contact surface 18a of the middle main girder 18 in the concrete 23 is also chamfered. Incidentally, as a form of this chamfering, as shown in FIG. 8, it may be configured to be inclined obliquely with respect to the substantially vertical direction in which the middle main beam 18 is erected. As a form of this chamfering, for example, as shown in FIG. 9, a horizontal plane 23a extending inward in the horizontal direction from the contact surface 18a in the middle main girder 18 and inclined upward from the horizontal plane 23a. You may make it fill the concrete 23 so that the inclined surface 23b may be formed. As a result, it is possible to create a state in which the concrete 23 is not in contact with the tunnel inner surface side corner portion 18 b of the middle main beam 18.

  Since the middle main girder 18 is designed so as to be welded symmetrically with the joint plate 13 and the vertical rib 14, the heat input due to the processing procedure and welding accuracy is actually slightly different between the right and left of the middle main girder 18. Even then, the thermal strain due to welding is smaller than the outer main girder. In this way, the deformation of the middle main girder 18 due to thermal strain is small, but when the middle main girder 18 is in contact with the concrete 23 in the vicinity of the tunnel inner side corner 18b, the concrete 23 and the vertical ribs 14 and the joint plate 13 Because of the difference in rigidity, stress concentration due to jack thrust acts on the concrete 23, and cracks are also likely to occur in the concrete 23. On the other hand, in the present invention, since the middle main girder 18 is not in contact with the concrete 23 in the vicinity of the tunnel inner side corner 18b, the stress concentration on the concrete 23 is also greatly reduced. It is possible to prevent the occurrence of cracks and the like.

  FIG. 10 shows an example in which the groove portions 31 in which the concrete 23 is lowered are formed at predetermined intervals. The groove 31 is formed at least around the welded portion between the vertical rib 14 and the outer main beam 11. The outward deformation of the outer main girder 11 occurs at a predetermined interval at the connecting portion of the vertical ribs 14 in the outer main girder 11. In addition, bolt boxes 99 for bolting with other segments adjacent in the tunnel axis direction are formed. For this reason, the groove part 31 is provided about the said part focusing on only the connection part periphery of this outer main girder 11 and the vertical rib 14. FIG. At this time, it is a condition that the contact position of the main girder 11 in the groove 31 is not more than the height of the main girder 11. Thereby, the height of the concrete 23 can be set to be equal to or less than the height of the outer main beam 11 at least around the welded portion of the vertical rib 14. Even in such a configuration, it is possible to prevent cracks and the like from occurring in the concrete 23 even if deformation based on the thermal strain generated in the outer main beam 11 occurs. Note that the width of the groove 31 may be about 20 to 50 mm from the vertical rib 14.

  The present invention can also be applied to the case where the outer main girder 40 includes the web 41, the inner air surface side flange 42a, and the outer peripheral surface side flange 42b as shown in FIG. The steel shell 39 includes a skin plate 12 that covers the outer peripheral surface side of the outer main girder 40 and a joint plate (not shown) that connects between the ends of the outer main girder 40. Is filled. Incidentally, FIG. 11A shows a cross-sectional configuration along the position where the vertical rib 14 is provided, and FIG. 11B shows a cross-section at a position separated from the vertical rib 14. In this outer main girder 40 shown in FIG. 11 (b), the state before welding is indicated by a dotted line, and the state after welding is indicated by a solid line. Since the outer main girder 40 has a flange 42a on the inner peripheral surface side of the tunnel, the amount of deformation is small compared to the outer main girder 11 without such a flange 42a, but at a position apart from the vertical rib 14, Deforms almost the same way.

  Here, the height from the skin plate 12 at the portion of the concrete 23 in contact with the main girder 40 is h7, and the height from the skin plate 12 on the steel shell inner lower surface 46 constituting the lower surface of the flange 42a on the inner air surface side. Is h8, the height h7 of the concrete 23 is equal to or less than the height h8 of the steel shell inner lower surface 46.

  Incidentally, the concrete 23 is configured to be horizontally extended in a direction away from the flange 42a and then inclined upward, but is not limited thereto. FIG. 12 shows another example of the form of the filling concrete 23 that contacts the outer main beam 40 described above. In FIG. 12A, the concrete 23 is inclined directly upward from a corner 42d inside and below the steel shell of the flange 42a. In the example of FIG. The concrete 23 is extended horizontally from the side 46 as it is.

  As shown in FIGS. 12A and 12B, the outer main girder 40 having the web 41 and the flange 42 includes the corner portions 42c and 42d on the concrete side of the inner surface side flange 42a and the concrete 23. In the section between the vertical ribs 14 and the adjacent vertical ribs 14 as shown in FIG. 11 (b), the inner surface flanges 42a and the webs 41 are heated. Since the outer main girder 40 is deformed due to distortion, the outer main girder 40 is also deformed in a wave shape. However, in the present invention, the concrete 23 is not filled to a height exceeding the inner surface 46 of the steel shell 46 in the flange 42a, so that the occurrence of cracks in the concrete 23 due to the deformation of the flange 42a and the web 41 can be suppressed. It becomes possible.

  From the viewpoint of safety factor, it is desirable that the height h7 of the concrete 23 is set to be about 1 to 2 mm lower than the height h8 of the steel shell inner lower surface 46.

  In the present invention, as an alternative to the configuration described above, an elastic body may be interposed between the outer main beam 11 and the concrete 23.

  FIG. 13 is a perspective view of the segment 5 in which such an elastic material is interposed, and FIG. 14A shows the HH ′ cross section of FIG. In this segment 5, the same components and members as those of the segment 4 described above are denoted by the same reference numerals, and the description thereof will be omitted.

  The elastic body 32 is interposed between the tunnel inner side corner 11 b on the inner air surface side of the outer main girder 11 and the concrete 23. In other words, the elastic body 32 needs to be interposed between the corners 11 b on the inner surface side of the outer main girder 11 so as not to be in direct contact with the concrete 23.

  The elastic body 32 is assumed to be composed of any one of an epoxy resin, a urethane elastomer, a urethane foam, and polyethylene that exhibits an anticorrosive effect, but is not limited thereto, and is an elastic material having a small elastic coefficient. Any material may be applied. Incidentally, since the concrete 23 is alkaline, it is desirable that the elastic body 32 be anti-alkaline to cope with this. Moreover, as this elastic body 32, you may make it apply organic resin sheets, such as an elastomer and foam, for example. Incidentally, the cross-sectional shape of the elastic body is rectangular in this embodiment, but it is needless to say that the cross-sectional shape is not limited to this and may be embodied in any shape.

  14A, the elastic body 32 is embedded in the concrete 23. However, the elastic body 32 and the concrete 23 share the same surface without being limited thereto. It may be in the form.

  When the elastic body 32 is actually disposed, the elastic body 32 may be attached to the outer main beam 11 in advance before the concrete 23 is filled.

  FIG. 14B shows an arrangement example of the elastic body 32 with respect to the steel shell 10 having the middle main girder 18. Similarly, with respect to the middle main girder 18, the elastic body 32 is interposed between the tunnel inner side corner 18 b of the middle main girder 18 and the concrete 23.

  The segment 5 to which the present invention having such a configuration is applied has the following effects. That is, in the segment 5, an elastic body 32 having a lower elastic modulus than concrete is interposed between the tunnel inner side corner 11 b of the outer main girder 11 and the concrete 23. Therefore, the concrete 23 is not in direct contact with the tunnel inner surface side corner portion 11 b of the outer main girder 11. For this reason, the elastic body 32 interposed between the tunnel inner side corner portion 11b of the outer main girder 11 and the concrete 23 is elastically deformed to absorb the deformation. For this reason, the stress concentration due to the wavy deformation of the main girder 11 with respect to the concrete 23 is greatly reduced. As a result, it is possible to prevent stress concentration from occurring on the concrete contacting the tunnel inner side corner 11b of the outer main girder as in the prior art, and as a result, the concrete 23 is cracked or chipped. Can be prevented. The same applies to the case where the middle main girder 18 is provided, and the elastic body 32 provided around the inner corner 18b of the tunnel can absorb this, so that the stress is concentrated on the concrete 23. It is possible to prevent the occurrence.

  Moreover, in this segment 5, you may make it suppress the material cost which contributes to the elastic body 32 by providing the elastic body 32 locally, as shown to Fig.15 (a). In this example, the elastic body 32 is formed at least around the welded portion between the vertical rib 14 and the outer main beam 11. The outward deformation of the outer main girder 11 occurs at a predetermined interval at the connecting portion of the vertical ribs 14 in the outer main girder 11. For this reason, the elastic body 32 is provided in the said part focusing on only the connection part periphery of this outer main girder 11 and the vertical rib 14. FIG. In the example of FIG. 15A, it is assumed that the surface of the elastic body 32 and the inner surface of the concrete 23 form the same surface.

  FIG. 15B shows an enlarged perspective view of the elastic body 32 at the formation position. The elastic body 32 is provided on the tunnel inner surface side of the vertical rib 14 and in contact with the tunnel inner surface side corner portion 11 b of the outer main girder 11. For this reason, the tunnel inner surface side of the vertical rib 14 is completely covered with the elastic body 32, and the concrete 23 near the tunnel inner surface side corner portion 11 b of the main girder 11 where the vertical rib 14 and the outer main beam 11 intersect. , The stress acting by the jack thrust is dispersed, and the stress concentration is greatly reduced. Even in this configuration, the desired effect of the present invention described above can be obtained. Incidentally, it is desirable that the distance between the outer main girder 11 and the concrete 23 with the elastic body 32 interposed therebetween is configured to be about 1 to 10 mm. This is because, in order to sufficiently distribute the stress, it is sufficient that the distance between the outer main girder 11 and the concrete 23 with the elastic body 32 interposed therebetween is about 1 to 10 mm.

  The segment 5 provided with the elastic body 32 is similarly applied to the case where it has an outer main girder 40 composed of a web 41, an inner air surface side flange 42a, and an outer peripheral surface side flange 42b as shown in FIG. Is possible.

  In such a case, the elastic body 32 is interposed between the side end portion 47 of the flange 42 a on the inner air surface side and the concrete 23. At this time, the elastic body 32 should just be coat | covered in the part which the corner | angular part 42c and the lower end corner | angular part 42d of the side edge part 47 of the flange 42a are buried in concrete. That is, in the example of FIG. 16, it is only necessary to cover at least the lower end corner portion 42d.

  In the outer main girder 40 having the web 41 and the flange 42, the web 41 and the inner air surface side flange 42a are deformed by thermal strain, and are deformed in a wave shape in the segment width direction. Since at least the side end portion 47 is covered with the elastic body 32 and the elastic body 32 is interposed between the side end portion 47 and the concrete 23, the deformation of the side end portion 47 is prevented. Is absorbed through the elastic body 32. Thereby, it becomes possible to suppress the occurrence of cracks in the concrete 23 due to the deformation of the flange 42a.

It is a figure which shows the example of the shield tunnel to which the segment made from the concrete filling steel which concerns on this invention is applied. It is a figure for demonstrating the structure of the steel shell which comprises the segment made from a concrete filling steel which concerns on invention. It is a figure which shows the state which filled the concrete with respect to the steel shell which consists of the above structures. It is FF 'sectional drawing in FIG. It is a figure for demonstrating the other form of chamfering. It is a figure which shows the state which the heat distortion generate | occur | produced in the outer main girder. It is a figure which shows the form which provided the middle main girder extended in the circumferential direction in the center of steel shell. It is sectional drawing which shows the state which filled the concrete with respect to the steel shell which provided the middle main girder. It is another sectional drawing which shows the state with which concrete was filled with respect to the steel shell which provided the middle main girder. It is a figure which shows the example which formed the groove part which made concrete low at the predetermined space | interval. It is a figure shown about the example which applied this invention to the NM segment. It is a figure which shows the other example of the form of the filling concrete which contacts the outer main girder mentioned above. It is a perspective view of the segment which interposes an elastic material. It is GG 'sectional drawing of FIG. It is a figure for demonstrating the structure which provided the elastic body locally. It is a figure for demonstrating the structure which provides an elastic body when applying this invention to an NM segment. It is a figure shown about the structural example of the segment made from concrete filling steel. It is a sectional side view in the crossing position of a main girder and a vertical rib. It is a figure which shows the planar form at the time of connecting the segment made from concrete filling steel in the axial direction C. FIG. It is a figure for demonstrating the problem of the prior art in the case of the main girder which has a flange each in an inner-space surface side and an outer peripheral surface side. It is a figure shown about the example which the crack 76 etc. produced from the location where the stress concentration D in the NM segment produced. It is a figure which shows the example which provided the stress distribution board in the outer peripheral side of the segment main body.

Explanation of symbols

2 Segment ring 3 Shield tunnel 4, 5 Segment 7 Concrete filled steel segment 8 Main girder 10 Steel shell 11, 40 Outer main girder 11a Contact surface 11b of outer main girder with concrete Corner 12 on inner side of tunnel of outer main girder Skin plate 13 Joint plate 14 Vertical rib 18 Middle main girder 18a Contact surface 18b of middle main girder with concrete 18b Corner inner surface side corner 21 of middle main girder 21 Bolt insertion hole 23 Concrete 31 Groove 32 Elastic body 41, 81 Web 42 Flange 42a Tunnel inner side flange 42b Tunnel outer side flange 42c Upper corner 42d inside the steel shell of the tunnel inner side flange 46d Lower corner 46 inside the steel shell of the tunnel inner side flange 46 Steel shell inner lower surface 47 Side end 65 Segment joint part 70 Steel shell 71 Main girder 72 Vertical rib 73 Joint plate 74 Skin plate 75 Concrete 82a Flange 82b on the inner air surface side Flange 88 on the outer peripheral surface side Welding part 83 Vertical rib 84 Skin plate 88 Welding part 91 Stress distribution plate 95a, 95b Connection surface 98 Bolt hole 99 Bolt box 108 Welding part

Claims (2)

The outer main girder that forms both side surfaces, the skin plate that covers at least the outer peripheral surface side between the outer main girders, the joint plate that joins between the ends of the outer main girder, and the outer main girder are joined. In a concrete-filled steel segment in which concrete is packed inside a steel shell having vertical ribs,
The outer main girder has a web and a flange formed on at least the inner surface of the web,
The steel shell has a middle main beam arranged in parallel with the outer main beam between the outer main beams,
The height of the concrete is not more than the lower inner surface of the steel shell of the flange formed on the inner air surface side at least in the contact surface to the outer main girder, and the height of the middle main girder is in the contact surface to the middle main girder. Less than the height, and less than the height of the outer main girder and / or the middle main girder around the welded portion between the vertical rib and / or the joint plate and the outer main girder and / or the middle main girder The concrete-filled steel segment is filled over the outer main girder and / or the middle main girder at a height higher than that of the outer main girder and / or the middle main girder. . The height of the concrete, according to claim 1, wherein the 1~5mm lower than at least the outer main beam and / or the outer main beam and / or main beam in the height at the contact surface to said in the main girder Concrete filled steel segment as described.

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