Tunnel support and support connecting method

Abstract

To provide a technique related to tunnel timbering which is more improved than before.SOLUTION: A tunnel support including first and second steel supports, top end portions of the first and second steel supports being connected to each other in a state in which the first and second steel supports are gripped by a pair of hands of an erector device, the first steel support having a first top end joint plate provided at a top end portion thereof and a female connection portion recessed at a single location thereof, the second steel support having a second top end joint plate provided at a top end portion thereof and a male connection portion recessed at a single location thereof and locked by being inserted into the female connection portion, the female connection portion is eccentrically arranged at a position close to the side edge with reference to the center position in the width direction of the first top end joint plate so as not to interfere with the web of the first steel support, and the male connection portion is eccentrically arranged at a position close to the side edge with reference to the center position in the width direction of the second top end joint plate so as not to interfere with the web of the second steel support.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a tunnel support and a support connection method. [Background technology]

[0002] The NATM (New Austrian Tunneling Method) is a well-known construction method for building tunnels. The NATM method is based on the idea of ​​maintaining the stability of the tunnel by effectively utilizing the support capacity and strength of the natural ground, and is a construction method that uses shotcrete, rock bolts, and steel supports appropriately to construct a tunnel structure that is integrated with the natural ground.

[0003] When constructing a tunnel using the NATM method, installing arch-shaped steel supports is usually done using the following procedure. First, a sprayer is set up near the tunnel face, and the first spray of concrete is applied to the face. Once this is complete, the sprayer is withdrawn. Next, a work vehicle equipped with an erector that sets up the supports is positioned near the face, and the erector is used to erect the arch-shaped steel supports into the tunnel wall near the face. Once this is complete, the work vehicle is withdrawn. Next, the sprayer is placed back at the face, the erected tunnel supports are embedded, and the second spray of concrete is applied, and the sprayer is withdrawn.

[0004] When erecting steel shoring, a common method is to use a hand attached to the end of the boom of heavy equipment such as an erector or a drill jumbo to grasp a pair of left and right divided shoring sections, which are divided into arc-shaped sections, and then erect them in an arch shape by butting together the joint plates attached to the top ends of the left and right divided shoring sections and bolting them together.However, in reality, this bolting is done manually.In other words, in a connection structure of divided shoring using bolt connections, it was necessary to abut the joint plates attached to the left and right divided shoring sections, and then position personnel on a work platform set up near the tunnel face or on a mancage attached to the boom of the heavy equipment, move the personnel to near the top of the tunnel, insert bolts between the joint plates of the divided shoring sections located near the top, and manually connect the bolts by fastening them with nuts.

[0005] In response to this, in recent years, a steel support connection structure has been proposed in which a male connector is provided on the joint plate of one of the left and right steel supports, and a female connector is provided on the joint plate of the other steel support, and the hand of a heavy machine (erector device) that grips the steel supports is moved relative to the other to engage the male connector with the female connector, thereby enabling a pair of steel supports to be connected in an arch shape (see, for example, Patent Document 1). This method of connecting a pair of steel supports by operating the hand of an erector device eliminates the need for conventional connecting work, such as placing personnel on work scaffolding set up near the tunnel wall or on a man cage of the erector device, and moving the personnel to the vicinity of the tunnel top to bolt the joint plates of the steel supports together, thereby improving workability while ensuring safety.

[0006] Furthermore, Patent Document 1 discloses a connection structure for steel shoring that employs a single-piece connection structure that connects a single female connector arranged on a joint plate of one steel shoring with a single male connector arranged on a joint plate of the other steel shoring. With this technology, a pair of split shoring can be connected together even if the pair of steel shoring is twisted relative to one another simply by aligning the central axis of the male connector with the central axis of the male locking member. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-163663 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the connection structure of steel shoring described in Patent Document 1, the female and male connectors are located at the center of the joint plates of the steel shoring. Therefore, it is necessary to provide a notch in the web of the steel shoring where the female connector is located to prevent interference with the female connector. This reduces the strength of the steel shoring and requires reinforcement to prevent this reduction in strength, leaving room for improvement in the conventional single-piece connection structure of steel shoring.

[0009] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a technique relating to tunnel support that is improved over conventional techniques. [Means for solving the problem]

[0010] The present invention employs the following means to solve the above problems: That is, the present invention is a tunnel support that is applied to the NATM construction method and includes first and second steel supports divided into arcs and erected along a tunnel wall formed by tunnel excavation, and whose top ends are interconnected while being held by a pair of hands of an erector device, wherein the first steel support has a first top joint plate provided at its top end and a female connector recessed at a single location of the first top joint plate, and the second steel support has a first top joint plate provided at its top end and a female connector recessed at a single location of the first top joint plate. and a male connecting portion recessed at a single location on the second top joint plate and engaged by being inserted into the female connecting portion, wherein the female connecting portion is eccentrically positioned near the side edge with respect to the center position of the width of the first top joint plate so as not to interfere with the web of the first steel support, and the male connecting portion is eccentrically positioned near the side edge with respect to the center position of the width of the second top joint plate so as not to interfere with the web of the second steel support.

[0011] Here, the female connecting portion may be eccentrically positioned at a position closer to the side edge on the mine mouth side based on the widthwise center position of the first top end joint plate, and the male connecting portion may be eccentrically positioned at a position closer to the side edge on the mine mouth side based on the widthwise center position of the second top end joint plate.

[0012] In addition, a wire mesh is fixed along the ground side flanges of the first and second top joint plates so as to protrude laterally from the face side edge and the tunnel mouth side edge of the ground side flange, and a guide member is provided on the face side edge of either the first or second top joint plate to assist in the insertion of the male connecting part into the female connecting part by guiding the face side edge of the other of the first or second top joint plate when connecting the support, and the guide member may be provided only on the face side edge of either the first or second top joint plate.

[0013] The present invention can also be specified as any of the tunnel support connection methods described above. That is, the support connection method of the present invention comprises operating a pair of hands of an erector device while holding the first and second steel supports with the pair of hands, and inserting the male connector into the female connector, thereby interconnecting the first and second steel supports. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a technology relating to tunnel support that is improved over conventional technology. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a side view of a tunnel support according to the first embodiment. [Figure 2] FIG. 2 is a diagram illustrating the tunnel support structure according to the first embodiment. [Figure 3] FIG. 3 is a top view of the work vehicle according to the first embodiment. [Figure 4] FIG. 4 is a side view of the work vehicle according to the first embodiment. [Figure 5] FIG. 5 is a front view of the first top end joint plate according to the first embodiment. [Figure 6] FIG. 6 is a rear view of the first top end joint plate according to the first embodiment. [Figure 7] FIG. 7 is a front view of the second top end joint plate according to the first embodiment. [Figure 8] FIG. 8 is a rear view of the second top end joint plate according to the first embodiment. [Figure 9] FIG. 9 is a schematic diagram showing a connection structure of the left-side steel support and the right-side steel support according to the first embodiment. [Figure 10] FIG. 10 is a diagram showing a state in which the female coupling portion and the male coupling portion according to the first embodiment are coupled together. [Figure 11] FIG. 11 is a side view of the vicinity of the top end of the left-side steel support and the right-side steel support according to the second embodiment. [Figure 12]FIG. 12 is a diagram illustrating wire meshes fixed to the left-side steel support and the right-side steel support according to the second embodiment. [Figure 13] FIG. 13 is a view of the guide member as viewed from the direction of arrow A in FIG. [Figure 14] FIG. 14 is a diagram illustrating a modified example of the guide member according to the second embodiment. [Figure 15] FIG. 15 is a diagram illustrating a modified example of the guide member according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] <Embodiment 1> FIG. 1 is a side view of a tunnel support 10 according to the first embodiment. The tunnel support 10 is applied to, for example, the NATM (New Austrian Tunneling Method) method, and is used for tunnel excavation. The tunnel shoring 10 is an arch-shaped steel shoring erected along the tunnel wall immediately after excavation to prevent the collapse of exposed ground. It is installed at regular intervals along the tunnel axis. In this embodiment, the tunnel shoring 10 includes a pair of arc-shaped steel shorings 10L, 10R. The pair of steel shorings 10L, 10R are formed from H-shaped steel beams with H-shaped cross sections. The steel shorings 10L, 10R are held by a pair of hands in an erector device, and their top ends are interconnected to form the arch-shaped tunnel shoring 10. Hereinafter, the steel shoring 10L will be referred to as the "left-side steel shoring" and the steel shoring 10R will be referred to as the "right-side steel shoring." In this embodiment, the left-side steel shoring 10L corresponds to the first steel shoring, and the right-side steel shoring 10R corresponds to the second steel shoring.

[0018] The left-side steel support 10L has a first main body 111, a first top joint plate 121, and a first bottom plate 131. The first main body 111 is an H-shaped steel beam consisting of a web 111a, a pair of ground-side flanges 111b and an inner space-side flange 111c that are perpendicular to the web 111a. The first top joint plate 121 is welded to one end of the first main body 111, and the first bottom plate 131 is welded to the other end. The first top joint plate 121 and the first bottom plate 131 are rectangular flat steel plates that extend perpendicular to the H-shaped cross section of the first main body 111. The ground-side flange 111b is the flange that is positioned facing the ground when the supports are connected (when the left-side steel support 10L and the right-side steel support 10R are connected). On the other hand, the inner space side flange 111c is the flange that is arranged facing the inner space side of the tunnel when the supports are connected.

[0019] Similarly, the right-side steel support 10R has a second main body 112, a second top joint plate 122, and a second bottom plate 132. The second main body 112 is an H-shaped support consisting of a web 112a, a pair of ground-side flanges 112b and an inner space-side flange 112c that are perpendicular to the web 112a. The second main body 112 is made of steel. A second top joint plate 122 is welded to one end of the second main body 112, and a second bottom plate 132 is welded to the other end. The second top joint plate 122 and the second bottom plate 132 are rectangular flat steel plates that extend perpendicular to the H-shaped cross section of the second main body 112. The ground-side flange 112b is the flange that faces the ground side when the shoring is connected. On the other hand, the interior space-side flange 112c is the flange that faces the tunnel interior space when the shoring is connected.

[0020] In this embodiment, the first top joint plate 121 and the second top joint plate 122 have a congruent square plane. As shown in Figure 1, the left-side steel support 10L and the right-side steel support 10R are connected with the first top joint plate 121 and the second top joint plate 122 butted against each other.

[0021] FIG. 2 is a diagram illustrating a tunnel support structure 1 according to the first embodiment. Reference numeral 3 in FIG. 2 denotes a primary shotcrete layer. Reference numeral 6 denotes a secondary shotcrete layer. FIG. 2 also illustrates a right-side steel support 10R of the tunnel support 10. In the tunnel construction method of this embodiment, after the natural ground 7 is exposed on the side of the tunnel T by excavating the tunnel face 8, primary concrete is sprayed onto this natural ground 7 to form the primary shotcrete layer 3. The arch-shaped tunnel support 10 described above is then erected along the tunnel wall surface on the inner side of the primary shotcrete layer 3. The tunnel support 10 is adjacent to the tunnel face 8 side of the existing tunnel support 10 located on the entrance side of the tunnel T, and is arranged at a predetermined interval (e.g., approximately 1.0 m to 1.5 m) in the axial direction of the tunnel T. The tunnel support 10 is erected using an erector device equipped with hands attached to the tips of a pair of booms.

[0022] FIG. 3 is a top view of the work vehicle 200 according to the first embodiment. FIG. 4 is a side view of the work vehicle 200 according to the first embodiment. The work vehicle 200 is a self-propelled heavy machine equipped with an erector device 100 and a spraying device 600 that erect the tunnel shoring 10. The erector device 100 is equipped with a pair of identically configured booms 17L, 17R. The pair of booms 17L, 17R can freely extend, retract, tilt, swing, and rotate by the operation of a drive mechanism attached to them. In addition, a pair of identically configured hands 18L, 18R are connected to the tip of each boom 17L, 17R. The pair of hands 18L, 18R can freely rotate and swing by the operation of a drive mechanism attached to them, and can detachably clamp and grip (hold) the left steel shoring 10L and the right steel shoring 10R, respectively. The erector device 100 holds the left-side steel support 10L and the right-side steel support 10R in a pair of hands 18L, 18R, and by driving each hand 18L, 18R, the left-side steel support 10L and the right-side steel support 10R can be connected and erected at the specified erection position.

[0023] Hereinafter, the boom designated by reference symbol 17L will be referred to as the "left boom," and the boom designated by reference symbol 17R will be referred to as the "right boom." Furthermore, the hand designated by reference symbol 18L will be referred to as the "left hand," and the hand designated by reference symbol 18R will be referred to as the "right hand." The erector device 100 can detachably hold the left steel support 10L with the left hand 18L, and detachably hold the right steel support 10R with the right hand 18R. In this embodiment, the left steel support 10L and the right steel support 10R are a pair of supports formed by dividing the arch-shaped tunnel support 10 into two halves. After being guided near the tunnel face 8, these are assembled at the tunnel face 8 to form the arch-shaped tunnel support 10.

[0024] The spraying device 600 is disposed between the left boom 17L and the right boom 17R, and includes an arm 601, a spraying robot 602 supported by the arm 601, and a spraying nozzle 603 provided at the tip of the spraying robot 602. The arm 601 is extendable and retractable. The spraying robot 602 is capable of tilting and rotating the spraying nozzle 603. The spraying device 600 also includes a concrete pump, an accelerator supply device, a compressor, a high-pressure water pump, etc. The spraying robot 602 can spray the shotcrete supplied from the concrete pump onto the working face 8 by discharging it from the spraying nozzle 603.

[0025] Tunnel T is constructed, for example, by repeating the following cycle: (1) Excavating the tunnel face 8 by blasting or machine → (2) Removing the debris → (3) Spraying the first shotcrete → (4) Erecting the tunnel supports → (5) Spraying the second shotcrete → (6) Casting rock bolts. This cycle is repeated to extend the tunnel T in the axial direction. (2) After the removal of the debris process is completed, the work vehicle 200 equipped with the erector device 100 is positioned near the tunnel face 8. At this time, the work vehicle 200 is self-propelled with the hands 18L, 18R of the erector device 100 holding the left steel support 10L and the right steel support 10R, respectively, along the tunnel axis (tunnel extension direction), and is positioned near the tunnel face 8. Then, in (3) spraying the primary shotcrete, the primary shotcrete is sprayed using a spraying device 600 onto the ground 7 (tunnel wall surface) where the left-side steel support 10L and the right-side steel support 10R will be erected, thereby forming the primary shotcrete layer 3. Next, in (4) erecting the tunnel support, the left-side steel support 10L and the right-side steel support 10R are held by the respective hands 18L, 18R, and the respective hands 18L, 18R are driven to connect the left-side steel support 10L and the right-side steel support 10R to each other at their top ends, and the arch-shaped tunnel support 10 is erected in the correct erection position.

[0026] The connection structure of the tunnel support 10 (left steel support 10L and right steel support 10R) will be described below.

[0027] Figure 5 is a front view of the first top joint plate 121 according to the first embodiment. Figure 6 is a rear view of the first top joint plate 121 according to the first embodiment. Here, reference numeral 121a denotes the outer surface of the first top joint plate 121, and reference numeral 121b denotes the inner surface of the first top joint plate 121. Reference numeral 121c denotes the upper edge of the first top joint plate 121, reference numeral 121d denotes the lower edge of the first top joint plate 121, reference numeral 121e denotes the tunnel entrance side edge of the first top joint plate 121, and reference numeral 121f denotes the face side edge of the first top joint plate 121. Here, the lower edge 121d of the first top joint plate 121 faces the interior of the tunnel T when the left-side steel support 10L and the right-side steel support 10R are connected, and the upper edge 121c faces the opposite side, i.e., the natural ground 7 side. In addition, the face side edge 121f of the first top joint plate 121 is positioned facing the face 8 side of the tunnel T when the left-side steel support 10L and the right-side steel support 10R are connected, and the mouth side edge 121e is positioned on the opposite side, i.e., facing the mouth side (the erector device 100 side).

[0028] In Figure 6, the end shape (H-shape) of the first main body portion 111 connected to the first top joint plate 121 is shown by a dashed line. Also, Figures 5 and 6 show the up-down direction (height direction) and width direction of the first top joint plate 121. The up-down direction of the first top joint plate 121 is parallel to the extension direction of the mouth-side side edge 121e and the face-side side edge 121f, and is also parallel to the extension direction of the web 111a at the position where the first main body portion 111 connects to the first top joint plate 121. Also, the width direction of the first top joint plate 121 is parallel to the extension direction of the upper edge 121c and the lower edge 121d, and is also parallel to the extension direction of the ground-side flange 111b and the interior-side flange 111c at the position where the first main body portion 111 connects to the first top joint plate 121. 5, the symbol X1 denotes the center line of the first top end joint plate 121 in the width direction. The symbol Y1 denotes the center line of the first top end joint plate 121 in the height direction.

[0029] Fig. 7 is a front view of the second top joint plate 122 according to embodiment 1. Fig. 8 is a rear view of the second top joint plate 122 according to embodiment 1. Here, reference numeral 122a denotes the second top joint plate 122. Reference symbol 122b denotes the inner surface of the second top joint plate 122. Reference symbol 122c denotes the upper edge of the second top joint plate 122, reference symbol 122d denotes the lower edge of the second top joint plate 122, reference symbol 122e denotes the tunnel mouth side edge of the second top joint plate 122, and reference symbol 122f denotes the face side edge of the second top joint plate 122. Here, the lower edge 122d of the second top joint plate 122 faces the interior of the tunnel T when the left-side steel support 10L and the right-side steel support 10R are connected, and the upper edge 122c faces the opposite side, i.e., the natural ground 7 side. In addition, the face side edge 122f of the second top joint plate 122 is positioned facing the face 8 side of the tunnel T when the left-side steel support 10L and the right-side steel support 10R are connected, and the mouth side edge 122e is positioned on the opposite side, i.e., facing the mouth side (the erector device 100 side).

[0030] In Figure 8, the end shape of the second main body portion 112 connected to the second top end joint plate 122 is shown by a dashed line. Figures 7 and 8 also illustrate the vertical and width directions of the second top end joint plate 122. Symbol X2 in Figure 7 is the center line of the second top end joint plate 122 in the width direction. Symbol Y2 is the center line of the second top end joint plate 122 in the height direction.

[0031] The first top joint plate 121 and the second top joint plate 122 shown in Figures 5 to 8 have a substantially square planar shape. The vertical dimensions of the first top joint plate 121 and the second top joint plate 122 are equal to each other, and the horizontal width dimensions of the first top joint plate 121 and the second top joint plate 122 are also equal to each other. In other words, the first top joint plate 121 and the second top joint plate 122 have congruent square planar shapes, and the dimensions of the upper edges 121c, 122c, the lower edges 121d, 122d, the mouth-side edges 121e, 122e, and the face-side edges 121f, 122f are equal to each other. However, the first top joint plate 121 and the second top joint plate 122 may also have a rectangular planar shape.

[0032] As shown in Figures 5 and 6, a single female coupling portion 40 is recessed into the first top joint plate 121. The female coupling portion 40 is eccentrically positioned closer to the side edge relative to the widthwise center of the first top joint plate 121 so as not to interfere with the web 111a of the left-side steel support 10L. More specifically, the female coupling portion 40 is eccentrically positioned closer to the mineshaft-side side edge 121e relative to the widthwise center of the first top joint plate 121. The female coupling portion 40 is also positioned at the vertical center of the first top joint plate 121. Reference character C1 in Figure 5 indicates the center of the female coupling portion 40. Reference character E1 in Figure 5 indicates the eccentricity from the center line X1 of the first top joint plate 121 in the width direction to the center C1 of the female coupling portion 40.

[0033] In addition, a single male connector 50 is protruding from the second top joint plate 122. The male connector 50 is eccentrically positioned closer to the side edge relative to the center position in the width direction of the second top joint plate 122 so as not to interfere with the web 112a of the right-side steel support 10R. More specifically, the male connector 50 is eccentrically positioned closer to the mineshaft-side side edge 122e relative to the center position in the width direction of the second top joint plate 122. The male connector 50 is also positioned at the center position in the height direction of the second top joint plate 122. Reference symbol C2 in Figure 7 indicates the center of the male connector 50. Reference symbol E2 in Figure 7 indicates the amount of eccentricity from the center line X2 in the width direction of the second top joint plate 122 to the center C2 of the male connector 50. In this embodiment, the eccentricity E2 of the male coupling part 50 in the width direction is set to a dimension equal to the eccentricity E1 of the female coupling part 40 in the width direction.

[0034] Figure 9 is a schematic diagram showing a connecting structure 30 that connects the left-side steel support 10L and the right-side steel support 10R according to embodiment 1. The connecting structure 30 is configured to include a single female connecting portion 40 provided on the first top joint plate 121 and a single male connecting portion 50 provided on the second top joint plate 122. Figure 9 shows the state before the left-side steel support 10L and the right-side steel support 10R are connected via the connecting structure 30, that is, the state in which the outer surface 121a of the first top joint plate 121 and the outer surface 122a of the second top joint plate 122 are opposed to each other but spaced apart. In FIG. 9, the first main body portion 111 connected to the first top end joint plate 121 and the second main body portion 112 connected to the second top end joint plate 122 are omitted for convenience.

[0035] First, we will explain the male coupling part 50 that is protruded from the second top joint plate 122. An opening 1222, which is a through-hole, is drilled in the second top joint plate 122 at the position where the male coupling part 50 is to be provided. The male coupling part 50 also has a rod-shaped male locking member 51. The male locking member 51 is a shaft member with a diameter slightly smaller than the opening 1222 of the second top joint plate 122, and has a male thread 51a engraved on its base end. A male thread 51c is formed over a predetermined range on the outer periphery of the male locking member 51. The male thread 51c of the male locking member 51 is a circumferential male locking groove that is arranged in multiple rows on the outer periphery of the male locking member 51. A tapered surface 51e that decreases in diameter toward the tip is formed on the tip 51d of the male locking member 51.

[0036] Here, a nut 52 is fixed to the inner surface 122b of the second top joint plate 122 by welding or the like at the drilling position of the opening hole 1222 in the second top joint plate 122. The male locking member 51 can be attached to the second top joint plate 122 in a state protruding from the outer surface 122a as shown in FIG. 9 by inserting its base end into the opening hole 1222 from the outer surface 122a side of the second top joint plate 122 and screwing a male screw 51a into the nut 52. As a result, the male connecting part 50 is protruding from the second top joint plate 122. Note that, as shown in FIGS. 7 and 8, the male connecting part 50 is positioned eccentrically to the side with respect to the center position in the width direction of the second top joint plate 122, so that the nut 52 for screwing the male locking member 51 does not interfere with the web 112a.

[0037] Next, the female coupling portion 40 recessed in the first top joint plate 121 will be described. An opening 1212, which is a through-hole, is drilled in the first top joint plate 121 at the position where the female coupling portion 40 is to be provided. A cylindrical metal casing 41 is fixed to the inner surface 121b of the first top joint plate 121 by welding or the like at the drilling position of the opening 1212 in the first top joint plate 121. The female coupling portion 40 is eccentrically positioned laterally relative to the center position in the width direction of the first top joint plate 121, thereby preventing the casing 41 from interfering with the web 111a. As shown in FIG. 9, a tapered surface 1215 is formed at the edge of the opening 1212 formed in the first top joint plate 121, gradually increasing in diameter from the inner surface 121b toward the outer surface 121a in the thickness direction of the first top joint plate 121.

[0038] The casing 41 has its axis positioned approximately in the center of the opening hole 1212. A storage chamber 42 is formed within the casing 41. A tapered hole 43 is formed at the front end (front portion) of the storage chamber 42, with the inner circumferential surface having a tapered surface 43a whose inner diameter gradually decreases from the rear end side to the front end side. A spring storage section 42a is formed in the middle portion of the storage chamber 42, and a female thread 45 is formed on the inner periphery of the rear portion of the storage chamber 42. An insertion opening 48 is formed at the front end of the tapered hole 43. The insertion opening 48 located at the front end of the casing 41 has approximately the same diameter as the opening hole 1212 formed in the first top end joint plate 121 and is connected to the opening hole 1212. When the casing 41 is fixed to the first top end joint plate 121, the insertion opening 48 is positioned so as to overlap the opening hole 1212.

[0039] Furthermore, within the tapered hole 43, a wedge-shaped female locking member 46 divided into three pieces in the circumferential direction is arranged so as to be slidable in the axial direction. The outer surface of the female locking member 46 is formed as a tapered surface 46a which is slidable along the tapered surface 43a in the tapered hole 43. The tapered surface 46a of the female locking member 46 has an outer diameter which gradually increases from the tip side to the rear. Furthermore, a female thread 46b is formed on the inner surface of each female locking member 46. The female threads 46b are multiple circumferential female locking grooves arranged side by side on the inner surface of each female locking member 46. The female threads 46b are carved in the shape of an arc centered on the axis of the casing 41 and in the direction along the axis. As described above, A female screw hole is formed by the plurality of female locking members 46, and the diameter of the female screw hole is enlarged when the tapered surface 46a of each female locking member 46 moves back along the tapered surface 43a of the tapered hole 43, and the diameter of the female screw hole is reduced when the female locking member 46 moves forward (toward the front). The female screw 46b formed on the inner surface of each female locking member 46 can be engaged with the male screw 51c formed on the outer periphery of the tip side of the male locking member 51.

[0040] Furthermore, in the spring storage section 42a of the storage chamber 42, pressure springs 44, which are pressure members that press (elastically bias) the female locking members 46 forward (forward), are stored in a compressed state between a spring receiver 47 provided at the rear end of each female locking member 46 and a cover plate 49, and the pressure of the pressure springs 44 constantly presses each female locking member 46 forward. The cover plate 49 can be held in a compressed state by being screwed onto a female screw 45 engraved on the inner circumferential side of the rear part of the storage chamber 42. A hexagonal hole 49a is provided on the outer surface of the cover plate 49, allowing the cover plate 49 to be freely attached and detached to the casing 41 with a hexagonal wrench.

[0041] Next, the procedure for connecting the left-side steel support 10L and the right-side steel support 10R will be described. When connecting the left-side steel support 10L and the right-side steel support 10R, the erector device 100 first grasps the left-side steel support 10L with the left hand 18L and grasps the right-side steel support 10R with the right hand 18R. Next, the erector device 100 appropriately extends and tilts the left-side boom 17L and the right-side boom 17R, and rotates the left-side hand 18L and the right-side hand 18R, thereby moving the left-side steel support 10L and the right-side steel support 10R so that they are perpendicular to the tunnel axis.

[0042] Then, as shown in Figure 9, from a state in which the first top end joint plate 121 on the left-side steel support 10L and the second top end joint plate 122 on the right-side steel support 10R are close to and facing each other, the distance between the first top end joint plate 121 and the second top end joint plate 122 is gradually narrowed so that the male locking member 51 of the male connecting portion 50 is inserted into the opening hole 1212 of the first top end joint plate 121.

[0043] Here, the outer diameter of the male locking member 51 is slightly smaller than the opening 1212 of the first top joint plate 121 and the insertion opening 48 of the female coupling part 40 (casing 41), and is set to be slightly larger than the diameter of the female screw hole formed by each female locking member 46 when each female locking member 46 is positioned in the most forward position of the tapered hole 43 (tapered surface 43a). When the male locking member 51 protruding from the second top joint plate 122 enters the insertion opening 48 of the female coupling part 40 through the opening 1212 of the first top joint plate 121, the tip end 51d of the male locking member 51 abuts against the front end surface 46c of each female locking member 46, which is positioned at the most forward position of the tapered hole 43 (tapered surface 43a) at its front end by the pressing force of the pressing spring 44. Then, the male locking member 51 moves each female locking member 46 backward along the tapered surface 43a toward the axial rear of the female connecting portion 40 (casing 41) against the pressing force of the pressure spring 44, thereby inserting the male locking member 51 into the storage chamber 42 while expanding the diameter of the female screw hole formed by the female screw 46b of the tapered surface 46a of each female locking member 46.

[0044] Then, the outer surface 121a of the first top joint plate 121 and the outer surface 122a of the second top joint plate 122 come into surface contact by abutting against each other, and when the insertion of the male locking members 51 into the storage chambers 42 in the female coupling portion 40 is completed and further insertion of the male locking members 51 into the storage chambers 42 is stopped, each female locking member 46 is pushed back forward (toward the front) by the pressing force of the compression spring 44, and the female screw holes formed by the tapered surfaces 46a of each female locking member 46 are reduced in diameter. As a result, as shown in Figure 10, the female threads 46b (female locking grooves) of each female locking member 46 in the female coupling portion 40 and the male threads 51c (male locking grooves) of the male locking members 51 in the male coupling portion 50 mesh with each other. As a result, as shown in FIG. 10, the outer surface 121a of the first top end joint plate 121 and the outer surface 122a of the second top end joint plate 122 are in surface contact with each other. The left steel support 10L and the right steel support 10R are connected together.

[0045] 10, when the female thread 46b of the female coupling portion 40 and the male thread 51c of the male coupling portion 50 (male locking member 51) are engaged, if an external force acts in a direction separating the first top joint plate 121 and the second top joint plate 122, a pull-out force acts in a direction pulling the male locking member 51 out of the storage chamber 42 in the female coupling portion 40. This pull-out force is transmitted to each female locking member 46 via the interlocking male thread 51c and female thread 46b. The tapered surface 46a of each female locking member 46 has an outer diameter that gradually decreases from the rear side to the front side. Therefore, even if the pull-out force acts on each female locking member 46, displacement of each female locking member 46 toward the front of the tapered hole 43 is limited. That is, with the connecting structure 30 according to this embodiment, even if an external force acts in a direction that pulls the male locking member 51 out of the storage chamber 42 of the female connecting portion 40, the connected state can be maintained against the external force. Note that when the male locking member 51 of the male connecting portion 50 is locked to the female connecting portion 40, that is, when the female threads 46b of the female locking members 46 of the female connecting portion 40 and the male threads 51c of the male locking member 51 are engaged with each other, pulling out of the male locking member 51 from the casing 41 of the female connecting portion 40 is restricted as described above, but rotation of the male locking member 51 about the central axis of the male locking member 51 relative to the casing 41 is permitted.

[0046] According to the steel shoring connection structure 30 of this embodiment, simply by inserting the male coupling portion 50 (male locking member 51) axially through the insertion port 48 of the female coupling portion 40, the male coupling portion 50 is connected to the female coupling portion 40 with one touch, thereby fastening the left steel shoring 10L and the right steel shoring 10R together. By adopting this one-touch connection structure, it is no longer necessary to perform the conventional connection work, such as placing personnel on a work platform set up near the tunnel wall or a man cage of an erector device, moving the personnel to the vicinity of the tunnel crown, and bolting the joint plates located at the top of the pair of steel shoring. Therefore, according to the steel shoring connection structure 30 of this embodiment, the left steel shoring 10L and the right steel shoring 10R can be connected more quickly and easily than conventional work. Furthermore, according to the steel support connection structure 30 in this embodiment, the left-side steel support 10L and the right-side steel support 10R can be connected by operating the hands 18L, 18R attached to the ends of a pair of booms 17L, 17R on the erector device 100, thereby avoiding manual work at the tunnel face and further improving safety and workability compared to conventional methods.

[0047] Furthermore, in the steel support connection structure 30 of this embodiment, a single-piece connection structure is adopted that connects a female connection part 40 that is solely arranged on the first top joint plate 121 and a male connection part 50 that is solely arranged on the second top joint plate 122.Therefore, by simply aligning the female connection part 40 and the male connection part 50 (male locking member 51), even if the first top joint plate 121 and the second top joint plate 122 are in a twisted state in a plane (the outer edges of the first top joint plate 121 and the second top joint plate 122 are not overlapping but are misaligned), the left-side steel support 10L and the right-side steel support 10R can be connected even more easily by inserting the male locking member 51 into the casing 41 (storage chamber 42).

[0048] Furthermore, according to the steel support connection structure 30 of this embodiment, as described above, even after the left-side steel support 10L and the right-side steel support 10R are connected, rotational movement of the male locking member 51 about the central axis CL2 relative to the casing 41 is permitted, so that after the above connection, the first top joint plate 121 and the second top joint plate 122 can be adjusted in position so that they are in full surface contact. As a result, when the female connecting portion 40 of the first top joint plate 121 and the male locking member 51 of the second top joint plate 122 are connected, the upper edge 121c, lower edge 121d, mouth-side edge 121e, and face-side edge 121f of the first top joint plate 121 overlap the upper edge 122c, lower edge 122d, mouth-side edge 122e, and face-side edge 122f of the second top joint plate 122, respectively. Therefore, alignment can be easily performed.

[0049] Furthermore, in this embodiment, the female connector 40 and the male connector 50 are eccentrically positioned near the side edges of the first and second top joint plates 121 and 122 relative to the widthwise center of the first and second top joint plates 121 and 122. This prevents the female connector 40 and the male connector 50 from interfering with the webs 111a and 112a of the left-side steel support 10L and the right-side steel support 10R, respectively. Therefore, unlike the connection structure disclosed in Patent Document 1, it is not necessary to form notches in the webs 111a and 112a of the left-side steel support 10L and the right-side steel support 10R. This eliminates the need to reinforce the webs 111a and 112a of the left-side steel support 10L and the right-side steel support 10R, thereby preventing the webs 111a and 112a from becoming weak points.

[0050] In particular, in this embodiment, the female coupling portion 40 is eccentrically positioned from the widthwise center position of the first top joint plate 121 toward the wellhead-side edge 121e, and the male coupling portion 50 is eccentrically positioned from the widthwise center position of the second top joint plate 122 toward the wellhead-side edge 122e. The wellhead-side edges 121e, 122e of each top joint plate 121, 122 can be said to be the side edges facing the erector apparatus 100 when connecting the shoring. Therefore, according to the above embodiment, the visibility of the female coupling portion 40 and the male coupling portion 50 is excellent when connecting the shoring. In other words, when connecting the shoring, for example, the operator of the erector apparatus 100 can easily see the female coupling portion 40 and the male coupling portion 50 from the cockpit, and the left steel shoring 10L and the right steel shoring 10R can be connected smoothly and easily. Furthermore, by eccentrically positioning the female connector 40 and the male connector 50 on the tunnel entrance side as described above, there is a further advantage as follows: For example, after erecting the tunnel support 10 formed in an arch shape by connecting the left-side steel support 10L and the right-side steel support 10R as described above, when a load from the tunnel face 8 acts on the tunnel support 10 due to the pushing out of the tunnel face 8, etc., the load tends to act in a direction that opens up the tunnel entrance side edges 121e, 122e at the connection between the first crown joint plate 121 and the second crown joint plate 122. In contrast, by adopting a connection structure in which the female connector 40 is eccentrically positioned from the widthwise center of the first top joint plate 121 toward the mouth-side edge 121e, and the male connector 50 is eccentrically positioned from the widthwise center of the second top joint plate 122 toward the mouth-side edge 122e, the female connector 40 and the male connector 50 function more effectively as resistance elements against the pushing force from the working face 8 (compared to when the female connector 40 and the male connector 50 are eccentrically positioned toward the working face 8, for example), and the opening at the mouth-side edges 121e, 122e of the first top joint plate 121 and the second top joint plate 122 can be suitably suppressed. In other words, the connection structure in which the female connector 40 and the male connector 50 are eccentrically positioned toward the mouth not only improves workability as described above, but also provides excellent resistance to pushing from the working face 8.

[0051] In the example shown in Figures 5 and 6, the eccentricity E1 of the female coupling part 40 is approximately 1 / 4 of the width dimension of the first top joint plate 121. That is, in the width direction of the first top joint plate 121, the female coupling part 40 is positioned at approximately the center position between the center position and the wellhead side edge 121e. However, the position of the female coupling part 40 in the width direction of the first top joint plate 121 is not limited to the above-mentioned embodiment, and the eccentricity E1 of the female coupling part 40 can be freely set. Also, in the example shown in Figures 5 and 6, the female coupling part 40 is positioned at approximately the center position in the up-down direction of the first top joint plate 121, but this is not limited thereto. The female coupling part 40 may be positioned eccentrically toward the upper edge 121c or the lower edge 121d in the height direction of the first top joint plate 121. Similarly, in the example shown in Figures 7 to 8, the eccentricity E2 of the male connector 50 is approximately 1 / 4 of the width dimension of the second top joint plate 122. In other words, in the width direction of the second top joint plate 122, the male connector 50 is positioned at approximately the center position between the center position and the wellhead side edge 122e. However, the position of the male connector 50 in the width direction of the second top joint plate 122 is not limited to the above-mentioned embodiment, and the eccentricity E2 of the male connector 50 can be set freely. Also, in the example shown in Figures 7 to 8, the male connector 50 is positioned at approximately the center position in the vertical direction of the second top joint plate 122. The male coupling portion 50 may be eccentrically disposed on the upper edge 122c side or the lower edge 122d side in the height direction of the second top end joint plate 122.

[0052] However, if the female connecting portion 40 and the male connecting portion 50 are positioned eccentrically near the side edges of each top end joint plate 121, 122 with respect to the widthwise center position of the first top end joint plate 121 and the second top end joint plate 122, interference between them and the webs 111a, 112a can be avoided, and to that extent the positions of the female connecting portion 40 and the male connecting portion 50 on each top end joint plate 121, 122 are not particularly limited.

[0053] In other words, for example, the female connecting portion 40 can be positioned eccentrically toward the face side edge 121f based on the widthwise central position of the first top end joint plate 121, and the male connecting portion 50 can be positioned eccentrically toward the face side edge 121f based on the widthwise central position of the second top end joint plate 122, thereby avoiding interference between the female connecting portion 40 and the male connecting portion 50 and the webs 111a, 112a.

[0054] When connecting the left-side steel support 10L and the right-side steel support 10R and erecting the arch-shaped tunnel support 10 in the specified erection position, prisms or the like attached to the left-side steel support 10L and the right-side steel support 10R may be automatically tracked by a surveying instrument such as a total station, and the hands 18L, 18R of the erector device 100 may be operated while acquiring their three-dimensional coordinates. Since such technology is well known, detailed explanations are omitted. However, for example, the tunnel support erection system disclosed in Patent Document 1 can be applied. Furthermore, the construction procedures disclosed in Patent Document 1 can also be applied to the erection procedure of the tunnel support 10 and the procedure for spraying the secondary shotcrete.

[0055] <Embodiment 2> Next, a second embodiment of the present invention will be described. Fig. 11 is a side view of the vicinity of the top ends of the left-side steel support 10L and the right-side steel support 10R according to the second embodiment. Fig. 12 is a diagram illustrating a wire mesh 15 fixed along the ground-side flange 111b of the left-side steel support 10L and the ground-side flange 112b of the right-side steel support 10R according to the second embodiment. This embodiment is the same as the first embodiment except that a guide member 14 is provided on the first top joint plate 121 of the left-side steel support 10L and that the wire mesh 15 is fixed to the ground-side flanges 111b, 112b of the left-side steel support 10L and the right-side steel support 10R. That is, in this embodiment, the configuration of the female coupling portion 40 in the first top joint plate 121 and the configuration of the male coupling portion 50 in the second top joint plate 122 are the same as those in the first embodiment. 11, the female coupling portion 40 and the male coupling portion 50 are shown schematically. In the following, the same components as those in the first embodiment are denoted by the same reference numerals and detailed explanations are omitted, and the explanation will focus on the differences from the first embodiment.

[0056] In this embodiment, a guide member 14 is provided on the face-side edge 121f of the first crown joint plate 121. The guide member 14 is a member that assists the insertion of the male coupling portion 50 into the female coupling portion 40 by guiding the face-side edge 122f of the second crown joint plate 122 during support connection. FIG. 13 is a view of the guide member 14 as viewed from the direction of arrow A in FIG. 11. The guide member 14 is made of, for example, a metal plate material. In the example shown in FIGS. 11 and 13, the guide member 14 is made to include a straight portion 141 formed on the base end side and an inclined portion 142 formed on the tip end side by, for example, bending the metal plate material midway. The straight portion 141 of the guide member 14 is joined by welding or the like to the face-side edge 121f of the first crown joint plate 121 so as to stand perpendicular to the outer surface 121a of the first crown joint plate 121. The inclined portion 142 of the guide member 14 is connected to the straight portion 141 at an incline. The inner surface position of 41 corresponds to the position of the face-side edge 121f of the first crown joint plate 121, and is inclined toward the outside of the first crown joint plate 121 (i.e., toward the face 8 side of the tunnel T when connecting the support) with the inclined portion 142 as the boundary. Note that the wire mesh 15 is not shown in Figure 13.

[0057] 11, the width dimension of the guide member 14 is smaller than the side length at the face-side edge 121f of the first top joint plate 121, and in the illustrated example, the guide member 14 is erected near the center of the face-side edge 121f. Therefore, as shown in FIG. 11, a step is formed between the upper end of the guide member 14 and the upper edge 121c of the first top joint plate 121. Furthermore, the protruding dimension of the straight portion 141 from the outer surface 121a of the first top joint plate 121 is set to a dimension equal to or greater than the protruding length of the male locking member 51 from the outer surface 122a of the second top joint plate 122.

[0058] Next, with reference to Figures 11 and 12, the wire mesh 15 of the left-side steel support 10L and the right-side steel support 10R will be described. The wire mesh 15 is a member for suppressing cracks in the secondary shotcrete layer 6, and is covered by the secondary concrete when the secondary concrete is sprayed onto the tunnel interior surface. The wire mesh 15 is fixed in advance by welding or the like to the upper surfaces of the ground-side flange 111b of the left-side steel support 10L and the ground-side flange 112b of the right-side steel support 10R. As an example, the wire mesh 15 has a lattice shape, and one mesh (one square) of the wire mesh 15 may be, for example, approximately 150 mm square. For example, the wire mesh 15 is arranged over the entire longitudinal length of the ground-side flanges 111b, 112b.

[0059] Of the wire mesh 15, the portion designated by reference numeral 15A is the portion that protrudes laterally from the face-side edges 1113, 1123 of the ground-side flanges 111b, 112b (hereinafter referred to as the "face-side protrusion"). On the other hand, the portion designated by reference numeral 15B is the portion that protrudes laterally from the wellhead-side edges 1114, 1124 of the ground-side flanges 111b, 112b (hereinafter referred to as the "wellhead-side protrusion"). The face-side edges 1113, 1123 of the ground-side flanges 111b, 112b are the side edges that face the face 8 when connecting the steel supports 10L, 10R. On the other hand, the wellhead side edges 1114, 1124 of the ground side flanges 111b, 112b are side edges located opposite the face side edges 1113, 1123, and face the wellhead side (i.e., the erector device 100 side) when the support is connected.

[0060] As shown in Fig. 12, the wire mesh 15 has a second protrusion length, by which the wellhead-side protrusion 15B protrudes laterally from the wellhead-side edges 1114, 1124, which is longer than a first protrusion length, by which the face-side protrusion 15A protrudes laterally from the face-side edges 1113, 1123. In the example shown in Fig. 12, the first protrusion length of the face-side protrusion 15A of the wire mesh 15 corresponds to a dimension of one mesh, and the second protrusion length of the wellhead-side protrusion 15B corresponds to a dimension of five meshes. In order to prevent the wellhead-side protrusion 15B of the wire mesh 15 fixed to the ground-side flanges 111b, 112b in this manner by welding or the like from bending downward (sagging) due to its own weight, support members 16 that support the wellhead-side protrusion 15B from below are provided on the left-side steel support 10L and the right-side steel support 10R. The support member 16 is not particularly limited as long as it is configured to support the wellhead-side protruding portion 15B, but can be configured to include a support anchor 161 and a spacer 162.

[0061] In the example shown in Fig. 12, the support anchor 161 is a rod-shaped anchor member protruding vertically from the webs 111a, 112a of the left-side steel support 10L and the right-side steel support 10R. For example, the base end of the support anchor 161 is welded to the portal-side web surfaces 1111, 1121 of the webs 111a, 112a. The portal-side web surfaces 1111, 1121 are the surfaces that face the portal on the opposite side from the face 8 when erecting the tunnel support 10. Also, reference numeral 163 shown in Fig. 12 denotes a bolt 164 of the support anchor 161 to ensure the perpendicularity of the support anchor 161 to the webs 111a, 112a (portal-side web surfaces 1111, 1121). The fixing device 163 is a fixing device for fixing the middle portion to the back surface of the ground-side flanges 111 b, 112 b. The fixing device 163 may be, for example, a nut welded to the back surface of the ground-side flanges 111 b, 112 b, and the middle portion of the support anchor 161 is fixed to the back surface of the ground-side flanges 111 b, 112 b by passing the support anchor 161 through the nut.

[0062] The spacer 162 is a member installed to maintain an appropriate distance between the wellhead-side protrusion 15B of the wire mesh 15 and the support anchor 161. The spacer 162 may be welded to the support anchor 161 and the wellhead-side protrusion 15B. Alternatively, the spacer 162 may be fixed to the wellhead-side protrusion 15B of the wire mesh 15 using a binding wire or the like. The support member 16 as described above prevents the wellhead-side protrusion 15B of the wire mesh 15 from bending due to its own weight and maintains the wellhead-side protrusion 15B in a position aligned with the ground-side flanges 111b and 112b. As shown in FIG. 12, the support anchor 161 is fixed to the upper side of the webs 111a and 112a, i.e., near the ground-side flanges 111b and 112b. This allows the distance between the wellhead-side protrusion 15B of the wire mesh 15 and the support anchor 161 to be reduced, thereby allowing the use of spacers 162 with a smaller height. The spacers 162 are arranged at appropriate intervals in the longitudinal direction of the support anchor 161.

[0063] Here, the symbol M1 shown in Figure 12 indicates the end mesh located at the tip end when the direction in which the mouth-side protrusion 15B of the wire mesh 15 protrudes laterally from the ground-side flanges 111b, 112b is used as a reference. The end mesh M1 of the mouth-side protrusion 15B corresponds to the overlapping space that is overlapped with the face-side protrusion 15A of the wire mesh 15 in the existing section closest to the tunnel face 8 in the axial direction of the tunnel T (the existing section in which the tunnel support 10 was erected immediately before). The end mesh M1 of the mouth-side protrusion 15B of the wire mesh 15, while overlapping with the face-side protrusion 15A in the existing section, may be appropriately tied together with a tie wire or a wire, or may be integrated by welding or the like, before the secondary concrete is sprayed onto the tunnel interior surface. In addition, the support anchors 161 are set to a length that will not interfere with the adjacent tunnel supports 10 on the existing side when erecting the tunnel supports 10 in the new section, thereby ensuring good workability.

[0064] The support anchors 161 are provided at predetermined intervals in the longitudinal direction of the first main body portion 111 and the second main body portion 112, thereby enabling the planar wire mesh 15 (the tunnel entrance-side protrusion 15B) to be appropriately supported from below. Similarly to the wire mesh 15, the support anchors 161 are embedded in the secondary concrete when the secondary concrete is sprayed onto the tunnel interior surface. Therefore, the support anchors 161 also function as crack prevention members for the secondary shotcrete layer 6. Because the support anchors 161 are embedded in the secondary shotcrete layer 6, they are anchored to the secondary shotcrete layer 6. Therefore, the support anchors 161 also function as anchoring members that anchor the tunnel support 10 to the secondary shotcrete layer 6. The support anchors 161 may be headed anchors with an enlarged head provided at their tip end, and such a configuration can further enhance the anchoring force to the secondary shotcrete layer 6.

[0065] Next, returning to FIG. 11, the details of the wire mesh 15 at the upper end side of the left-side steel support 10L (first main body portion 111) and the right-side steel support 10R (second main body portion 112) will be described. The symbol M2 shown in FIG. 11 is the end mesh of the wire mesh 15 provided on the left-side steel support 10L that is located at the tip end side in the longitudinal direction of the left-side steel support 10L (first main body portion 111). The symbol M3 is the end mesh of the wire mesh 15 provided on the right-side steel support 10R that is located at the tip end side in the longitudinal direction of the right-side steel support 10R (second main body portion 112). In the example shown in FIG. 11, the end mesh M2 of the wire mesh 15 provided on the left-side steel support 10L extends beyond the first top joint plate 121. The end mesh M2 of the wire mesh 15 is When the left-side steel support 10L and the right-side steel support 10R are connected, the meshes M2 and M3 overlap with the end mesh M3 of the wire mesh 15 provided on the right-side steel support 10R. The end meshes M2 and M3 may be integrated as appropriate using binding wires, wires, welding, etc. before the secondary concrete is sprayed onto the interior surface of the tunnel.

[0066] Tunnel support 10, consisting of left-side steel support 10L and right-side steel support 10R configured as described above, is equipped with guide member 14, which allows left-side steel support 10L and right-side steel support 10R to be easily connected. That is, when connecting left-side steel support 10L and right-side steel support 10R, in the process of bringing first top joint plate 121 and second top joint plate 122 closer together, inclined portion 142 of guide member 14 guides face-side side edge 122f of second top joint plate 122, making it possible to align the relative positions of female coupling part 40 and male coupling part 50 (male locking member 51) in the tunnel axis direction. Furthermore, since the protruding dimension of the straight portion 141 relative to the first top end joint plate 121 is equal to or greater than the protruding length of the male locking member 51 relative to the second top end joint plate 122, the alignment of the female connecting portion 40 and the male locking member 51 in the tunnel axial direction can be completed before the male locking member 51 collides with the outer surface 121a of the first top end joint plate 121.

[0067] Here, when the operator of the erector device 100 visually operates each hand 18L, 18R, it is difficult to visually confirm the positional deviation of the female coupling portion 40 and the male coupling portion 50 (male locking member 51) in the tunnel axis direction. In contrast, the guide member 14 of this embodiment makes it easy to align the female coupling portion 40 and the male coupling portion 50 (male locking member 51) in the tunnel axis direction, thereby enabling smooth shoring connection.

[0068] 11 and 13, the guide member 14 is provided only on the face-side edge 121f of the first top joint plate 121, and no guide member is provided on any of the other side edges of the first top joint plate 121, i.e., the upper edge 121c, the lower edge 121d, and the mineshaft-side edge 121e. By not providing a guide member on the upper edge 121c of the first top joint plate 121, it is possible to avoid the guide member colliding with the wire mesh 15 (particularly, the end mesh M3) on the right-side steel support 10R side when connecting the support, and to suitably suppress deformation and damage to the wire mesh 15 (particularly, the end mesh M3). In addition, by not installing guide members on the lower edge 121d and the tunnel entrance side edge 121e of the first top end joint plate 121, it becomes easier for the operator of the erector device 100 to visually check the relative positions of the female connecting portion 40 and the male connecting portion 50 when connecting the support, making it possible to connect the support smoothly.

[0069] 11 and 13, the guide member 14 includes the straight portion 141 and the inclined portion 142. However, the guide member 14 is not limited to this. For example, as in the modified example shown in FIG. 14, the guide member 14 may be formed of only the straight portion 141. Furthermore, the guide member 14 in this embodiment may be formed of a member other than a metal plate. For example, as in the modified example shown in FIG. 15, the guide member 14 may be formed of a rod-shaped member. The rod-shaped member forming the guide member 14 may be a reinforcing bar. In this case, the straight portion 141 and the inclined portion 142 can be easily formed by bending the reinforcing bar from the middle.

[0070] 11, the wire mesh 15 provided on the left-hand steel support 10L is bent slightly diagonally upward from the base of the end mesh M2, so that the end mesh M2 is inclined diagonally upward. This makes it less likely that the end mesh M2 of the wire mesh 15 on the left-hand steel support 10L side will collide head-on with the end mesh M3 of the wire mesh 15 on the right-hand steel support 10R side when the supports are connected, thereby making it possible to effectively suppress deformation and damage to the wire mesh 15 that would otherwise result and to smoothly connect the supports.

[0071] In this embodiment, the guide member 14 may be provided on the face-side edge of either the first top joint plate 121 or the second top joint plate 122, thereby guiding the face-side edge of the other of the first top joint plate 121 or the second top joint plate 122 during support connection, and assisting the insertion of the male coupling part 50 into the female coupling part 40. Therefore, although FIGS. 11 to 13 show an example in which the guide member 14 is provided on the face-side edge 121f of the first top joint plate 121, the guide member 14 may instead be provided on the face-side edge 122f of the second top joint plate 122. In that case, it is preferable to provide the guide member 14 only on the face-side edge 122f of the second top joint plate 122.

[0072] Although the embodiments of the present invention have been described above, the aspects disclosed in the respective embodiments can be combined as much as possible. [Explanation of symbols]

[0073] 10. Tunnel support 10L...Left side steel shoring 10R...Steel shoring on the right side 14 Guide member 15. Wire mesh 40...Female connection part 50...Male connection part 51...Male locking member 121···First top joint plate 122···Second top joint plate

Claims

1. A tunnel support that is applied to the NATM method and includes first and second steel supports divided into arcs and erected along the tunnel wall formed by tunnel excavation, and whose top ends are interconnected while being held by a pair of hands of an erector device, The first steel support has a first top end joint plate provided at the top end and a female coupling portion recessed in the first top end joint plate, The second steel support has a second top joint plate provided at the top end, and a male connecting portion recessed in the second top joint plate and inserted into the female connecting portion to be engaged, A wire mesh is fixed along the ground side flange of the first top joint plate and the second top joint plate so as to protrude laterally from the face side edge and the tunnel mouth side edge of the ground side flange, a support member that supports the wire mesh from below, the support member being fixed to the ground-side flange; Tunnel support.

2. The tunnel support according to claim 1 , wherein the support member is fixed to the ground-side flange via a fastener provided on a back surface of the ground-side flange.

3. 3. The tunnel support according to claim 2, wherein the fixing device is a nut welded to the back surface of the ground-side flange, and the support member has a rod-shaped member that is passed through the nut.

4. a second protruding length of a wellhead-side protruding portion of the ground-side flange protruding laterally from the wellhead-side edge portion of the ground-side flange is longer than a first protruding length of a face-side protruding portion of the ground-side flange protruding laterally from the face-side edge portion of the ground-side flange; The support member is a member that supports the portal-side protrusion from below, and extends along the bottom of the portal-side protrusion from only the portal-side edge of the ground-side flange and the face-side edge.

5. A guide member is provided on the face-side edge of either the first top joint plate or the second top joint plate to assist the insertion of the male coupling portion into the female coupling portion by guiding the face-side edge of the other of the first top joint plate or the second top joint plate when connecting the support, 2. The tunnel support according to claim 1, wherein the guide member is provided only on the face-side edge of one of the first top joint plate and the second top joint plate.

6. A tunnel support connection method according to any one of claims 1 to 5, The first and second steel supports are held by a pair of hands of an erector device, and the pair of hands is operated while the first and second steel supports are held by the pair of hands, and the first and second steel supports are interconnected by inserting the male connector into the female connector. Shoring connection method.

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